Method of producing high-purity methacrylic acid

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing pure methacrylic acid, which involves: a) gas-phase oxidation of a C4 compound to obtain a methacrylic acid-containing gas phase, b) condensing the methacrylic acid-containing gas phase to obtain an aqueous methacrylic acid solution, c) separating at least a portion of the methacrylic acid from the aqueous methacrylic acid solution to obtain at least one methacrylic acid-containing raw product, d) separating at least a portion of methacrylic acid from the at least one methacrylic acid-containing raw product by thermal separation to obtain pure methacrylic acid, wherein at step (d), methacrylic acid is separated from at least a portion of at least one methacrylic acid-containing raw product by fractionation, and wherein the pure methacrylic acid is collected through a side outlet used for the fractionation column, and the amount of pure methacrylic acid collected over a certain time interval ranges from 40% to 80% of the amount of the methacrylic acid-containing raw product fed into the fractionation column over the same time interval. The invention also relates to an apparatus for producing methacrylic acid using said method, the apparatus comprising: a1) a gas-phase oxidation unit, b1) an absorption unit, c1) a separation unit, and d1) a purification unit, wherein the purification unit has at least one distillation column, wherein the at least one distillation column has at least one side outlet for pure methacrylic acid. The invention also relates to a method of producing methacrylic esters, polymethacrylate, polymethacrylic esters, which includes a step for said production of pure methacrylic acid.

EFFECT: obtaining an end product with fewer by-products while simplifying the process.

32 cl, 3 tbl, 4 dwg, 6 ex

 

The present invention relates to a method of obtaining pure methacrylic acid, high purity methacrylic acid obtained in this way, the device for producing methacrylic acid by the method of producing esters of methacrylic acid, esters of methacrylic acid obtained in this way, the method of production of polymethacrylates, to obtain by this way the polymethacrylates, to a method for producing esters of poly (methacrylic acid, esters of polymethacrylic acid, obtained by this method, to the use of pure methacrylic acid obtained corresponding to the invention method, and esters of methacrylic acid, obtained relevant to the invention method, and are also produced from these fibers, films, lacquers, coatings, materials for producing molded bodies, molded bodies, additives for paper production, additives to the skin, flocculants and additives for drilling fluids.

Methacrylic acid (MAC), and such esters of methacrylic acid as the methyl methacrylate (MMA) and butylmethacrylate and including polymeric materials have many applications. Typical end products include products made of acrylic plastic and sheet material, a resin for injection molding, modifiers for PVC, additives used in the processing, acrylic lacquers, p is oductio to care for floor coverings, insulating materials and sealants, fluids for automobile transmissions, additives to oils for engine crankcase, cover for cars, ion-exchange resins, adhesives for electronics, coatings for metals and acrylic fibers. In particular, methacrylic acid and esters of methacrylic acid are highly appreciated in these and other applications, because they increase the hardness of the products in which they are used. In the case of use in a specific product they increase chemical resistance, resistance to irradiation of visible light and UV radiation. In this regard, methacrylic acid and esters of methacrylic acid is often used in the fields of practical applications that require resins with very good transparency, strength and durability when using them outdoors.

Other applications submitted by the receipt of such copolymers as methyl methacrylate-butadiene-styrene copolymer, which is used as a modifier for PVC, paints and varnishes, water-based coatings, for example, latex paints for indoor applications, adhesive compositions, and more recently in the light-diffusing plates for uniform illumination in liquid crystal displays for computers and televisions, for the example, in flat screens, as well as in contact lenses. The methyl methacrylate is also used to obtain non-corroding cast prostheses such anatomical structures as a coronary artery of the heart.

Special derivatives, methacrylate esters, for example, with alkylamine and akrilovye alcohols, hydroxyaspartate, glycols, Quaternary ammonium derivatives and aminoalcohols, along with other areas of application are, for example, contact lenses, coatings, means for increasing the bioavailability of drugs in the media with controlled release of active substances, adhesives, lubricants, tools to improve the fluidity, the means to improve compatibility in polymer blends, the connecting means, they are used for food packaging, in varnishes and free from PVC means for processing the bottom of the car body.

In many applications of methacrylic acid and/or its derivatives serious attention is paid to appearance, in particular, color products, when in the preferred case, the products must be colorless.

Commercial production of methacrylic acid is carried out, among other ways, by gas-phase oxidation by heterogeneous catalyst of isobutylene, tert-butanol, METAR leina or samalanga aldehyde. The resulting gazoobraznoi reaction phase is transformed into an aqueous solution of methacrylic acid with cooling, and or, if necessary, it is separated from such low-boiling substances, such as acetaldehyde, acetone, acetic acid, acrolein and methacrolein, and then sent to the column solvent extraction in order to extract and separate methacrylic acid using a suitable means for extraction, such as short-chain hydrocarbons. Then for obtaining pure methacrylic acid selected methacrylic acid cleaned, for example, by distillation, to separate her from such high-boiling impurities, such as, for example, benzoic acid, maleic acid and terephthalic acid. Such a known method described, for example, in the application for European patent No. 0710643 A1. Along with this, the so-called4-process for production of methacrylic acid can also be used so-called acetone-legitimacy process (ASN-process), according to which as a source of compounds used hydrocyanic acid and acetone. Acetone-cyanhydrin is formed by the reaction of acetone with hydrocyanic acid and is converted into methacrylic acid in the presence of water and sulfuric acid. This method is described, for example, in the application for the European patent No. 0999200 A1.

In particular, formed as by-products upon receipt of methacrylic acid in the C4-the process of aldehydes, which absorb in the ultraviolet region, lead, even at very low concentrations, to undesirable staining of methacrylic acid in yellow color, which also leads to undesirable staining derived from a methacrylic acid final products. The intensity of staining of methacrylic acid quantitatively characterize the so-called "indicator ARNA", which is usually determined in accordance with ASTM D 1209. Known earlier ways of weakening such staining methacrylic acid by adding reagents that interact with such aldehydes. In this regard, it is known, for example, the addition of amines such as, for example, hydrazine, Ethylenediamine, aniline or polyamine, and adding p-phenylendiamine, as described in the application for European patent No. 0312191 A2.

Yet the disadvantage of the previous methods of obtaining pure methacrylic acid with implementation4process is that in addition to the extraction process, you need to use at least two additional stages of distillation in order to separate low-boiling and high-boiling impurities. Because of thermal effects is the influence of methacrylic acid has a tendency to the formation of the dimer of methacrylic acid, of methacrylic acid oligomers and polymers of methacrylic acid, such additional stage distillation result in reduction of the yield of methacrylic acid by the formation of dimers, oligomers or polymers.

In accordance with the foregoing, the main object of the present invention consisted in overcoming or at least mitigating the negative factors previously known methods.

In accordance with the present invention is to develop a simpler, more effective, implemented in a shorter time and with lower cost way to increase the purity of methacrylic acid, in particular, in order to make it more suitable for use in the production of other products of its transformation, in particular, where as complete as possible to minimize staining products.

Contribution to the solution of at least one of the above problems make the main provisions of the main points of the claims. In referring to the main points of the claims subparagraphs describe the preferred implementations of the invention.

The solution to the above problems is provided a method of obtaining pure methacrylic acid, including at least a stage of the method:

a) oxidation in the gas phase With4connection with the purpose of obtaining gas the phase which includes methacrylic acid,

b) condensation containing methacrylic acid in the gas phase to obtain an aqueous solution of methacrylic acid,

C) allocating at least part of the methacrylic acid from the aqueous methacrylic acid with the aim of obtaining at least one containing methacrylic acid crude product,

d) allocating at least part of methacrylic acid of not less than one containing methacrylic acid crude product with the use of the method of thermal separation to obtain pure methacrylic acid.

Directed by oxidation in the gas phase C4connection at the stage a) corresponding to the invention of the method in the preferred case represents a C4-compound selected from isobutylene, tert-butyl alcohol and methacrolein or from a mixture of two or more of these compounds.

In the preferred case, the oxidation in the gas phase at the stage a) corresponding to the invention the method proceeds in the presence of at least one oxidation catalyst. In the case when C4connection is an isobutylene or tert-butyl alcohol, oxidation in the gas phase in order to obtain the gas phase, which includes methacrylic acid, can be carried out in one stage, given the th context of the single-stage process is seen as flowing primarily in one reaction volume in the presence of at least one primary catalyst oxidation of methacrolein and following this oxidation to methacrylic acid. In the alternative case, the oxidation in the gas phase at the stage a) can be carried out at more than one stage, in the preferred case in two stages, in the preferred case in two or more reaction volumes, which are separated from one another, in the preferred case of using two or more catalysts, each catalyst in the preferred case is contained in a separate reaction volumes, separately from the other catalysts. At the two-stage oxidation in the gas phase the first stage in the preferred case is an at least partial oxidation of C4connection to methacrolein, followed by at least partial oxidation of methacrolein to methacrylic acid, In accordance with this, for example, in the first stage of the reaction, preferably the presence of at least one catalyst suitable for the oxidation of at least one C4connection to methacrolein, and the second stage of the reaction is not less than one catalyst suitable for the oxidation of methacrolein to methacrylic acid.

Suitable reaction conditions for the catalytic oxidation in the gas phase are, for example, temperatures from about 250°C to about 450°C, in the preferred case from about 250°C to primer is 390°C, and the pressure from about 1 ATM to about 5 ATM. Space velocity may vary from about 100 to about 6000 h-1(NTP), and in the preferred case from about 500 to about 3000 h-1. Oxidation, for example, oxidation in the gas phase, this initial C4connection, as isobutylene to methacrolein and/or to methacrylic acid and used for this purpose, the catalysts are widely presented in the literature, they are known, for example, U.S. patents№5248819, №5231226, №5276178, №6596901 B1, №4652673, №6498270, №5198579, №5583084.

In particular, the preferred catalysts and methods suitable for the oxidation of isobutylene or tert-butanol to methacrolein and/or to methacrylic acid as described in the application for the European patent No. 0267556 A2, in particular, the preferred catalysts for the oxidation of methacrolein to methacrylic acid as described in the application for the European patent No. 0376117 A1. These documents are included in these materials as reference and form part of the description of the present invention.

Oxidation in the gas phase of methacrolein to methacrylic acid of the invention the method in the preferred case takes place at temperatures from about 250°C to about 350°C and lower at a pressure from about 1 ATM to about 3 ATM and at a space velocity from about 800 to about 1800 normal if the ditch per liter per hour (nl/l/h).

As oxidant in the General case, apply oxygen, for example, in the air or as pure oxygen or as oxygen, diluted to such at least one inert under the conditions of the reaction gas, at least one of the enumerated next: nitrogen, carbon monoxide and carbon dioxide, while the preferred oxidant is air, and nitrogen and/or carbon dioxide are the preferred gases for diluting. If the diluent used carbon dioxide, in the preferred case, this carbon dioxide back into the process after combustion, in the preferred case, after catalytic or thermal incineration, which is carried out on completion of at least one of the steps C), d) and e) corresponding to the invention method. The gas supplied into the gas phase oxidation stage (a) corresponding to the invention of the method, in the preferred case also contains water, which in General present in the form of water vapor. Oxygen, inert gas or gases and water can be fed into the reaction phase together with4connection before carrying out the reaction in the gas phase or during the reaction or the same as before the reaction and during the reaction in the gas phase.

In the preferred embodiment, to meet the future invention of the method to the step (a) serves a mixture, include at least one4connection, air or oxygen and is returned to recycling the effluent from the reactor gas, in the preferred case coming out of the reactor gas, which before returning for recycling was subjected to burning. Preferably, when coming out of the digester gas contains at least one unreacted4connection, at least one oxide of carbon, nitrogen and oxygen, and water depending on the conditions of separation and possible participation in the process stage of combustion and efficiency.

In accordance with the invention when the two-stage oxidation in the gas phase the preferred volumetric ratio With4connection: oxygen: water: inert gas in the first stage is in General 1:0.5 to 5:1 to 20:3-30, in the preferred case 1:1-3:2-10:7-20. The volumetric ratio of methacrolein: oxygen: water: inert gas in the second stage is 1:1-5:2-20:3-30, in the preferred case 1:1-4:3-10:7-18.

At the stage b) corresponding to the invention, a method condense the gas phase containing methacrylic acid, and receive the condensate in the form of an aqueous solution comprising methacrylic acid. Condensation can be performed in any well-known specialist in a suitable way, for example, by cooling the containing methacrylic acid in the gas phase to a temperature below the point the dew no less than one component, in particular, at least one of the component represented by the water and methacrylic acid. Suitable cooling methods known to the expert, including, for example, cooling at least one heat exchanger or rapid cooling, for example, by spraying the gas phase with a liquid, for example water, aqueous composition or organic solvent such as, for example, aromatic or aliphatic hydrocarbons or a mixture of at least two of them, in the preferred case, the organic solvents have a relatively low vapor pressure under conditions of rapid cooling, it may be heptane, toluene or xylene, in accordance with the invention, preference is given to water, and in even more preferred is the use of at least a portion of the condensate formed during rapid cooling. Suitable methods of rapid cooling is known to the expert, for example, according to the materials of the Federal Republic of Germany patent No. 2136396, a European patent application No. 297788 A2, No. 297445 A2, Japan patent No. 01193240, No. 01242547, No. 01006233, applications for U.S. patent No. 2001/0007043 A1, No. 6596901 B1, U.S. patent 4956493, application for U.S. patent 4618709 B1, U.S. patent 5248819, the main provisions which related to rapid cooling of acrylic and methacrylic acids, are included in these materials and form part of the description of the present invented who I am. In accordance with the invention, preferably, when the gas phase is cooled to a temperature of from 40 to 80°C and washed with water and/or condensate from the stage of rapid cooling in order to obtain containing methacrylic acid aqueous solution, which may also include variable amounts of such impurities as acetic acid, maleic acid, fumaric acid, Tarakanova acid, acrylic acid and formic acid, as well as such aldehydes as formaldehyde, acetaldehyde, propionic aldehyde, acrolein, methacrolein, ketones and unreacted4connection or connections. These impurities and water, should be separated as much as possible in order to obtain a methacrylic acid higher degree of purity.

In the preferred embodiment corresponding to the invention of the method stage of the process includes the following process steps:

1α) extraction of methacrylic acid from the aqueous methacrylic acid with an organic extractant to obtain the aqueous phase and organic phase,

1β) separating at least part of the organic solvent from the organic phase using at least one thermal separation process to obtain at least one containing methacrylic acid cubic product, p is establisheda containing a methacrylic acid crude product.

Extraction of methacrylic acid containing from methacrylic acid aqueous solution at the stage of selection in accordance with the operation 1α) is carried out using an organic extractant, for example at least one organic solvent, which is generally not miscible with water, and hold it so that could be formed in the aqueous phase and organic phase. Preferred organic solvents that can be applied at the stage in the respective inventions ways, have different boiling point, however, in the preferred case, the boiling point is not higher than the boiling point of methacrylic acid. Preferably, when the invention method, the organic extractant used in the process in operation 1α), has a boiling point of less than 161°C, in particular at atmospheric pressure. The organic extractant may then be in principle separated from methacrylic acid, for example, via distillation, in the preferred case, at least partially, in the preferred case is distilled off its main part on technological operations 1β) corresponding to the invention, a method, in accordance with which it may be at least partially selected as a more low-boiling compared to the pure methacrylic acid fracc is at a higher level device for distillation. The separated organic extractant may be again returned to the manufacturing operation 1α), if necessary after at least one operation cooling and/or after cleaning. Preferred organic solvents for this step selects, in particular, of the alkanes and aromatic compounds, in the preferred case, it alkylaromatic compounds, hydrocarbons, and in the particularly preferred case, at least one organic solvent selected from heptane, toluene and xylene, and the most preferred solvent is heptane, preferably n-heptane. The extraction can be performed by any known method, which is evaluated by a specialist as appropriate for this, for example, it may be a wash column, a separator for phase separation or other devices suitable for separating the organic phase from the aqueous phase. The organic phase shifts at least part of methacrylic acid, in the preferred case, not less than about 50 wt.%, in a more preferred case, not less than about 70 wt.%, in a more preferred case, not less than about 80 wt.%, in the most preferred case, not less than about 90 wt.% contained in an aqueous solution of methacrylic acid.

Operations 1β) this option sootvetstvujushej the invention of the method of organic extractant is at least partially separated from the organic phase by using the process of thermal separation. Appropriate processes thermal separation known to the expert, in accordance with the invention, preference is given to distillation, rectification and similar processes. In accordance with the invention can be one or more separation processes. During the distillation separates a component with a boiling point below the boiling point of methacrylic acid, in the preferred case they are selected at the head of the distillation column or at the appropriate level column for fractionation or distillation column, and in the cubic phase is enriched methacrylic acid. Low-boiling components, which in the preferred case, along with the organic extractant is separated at the head of the column, can be represented above by-products and unreacted C4connection or With4connection. You can also at least partially to isolate unreacted4connection or With4connection by flushing the outgoing gas from the column with water at low temperature or blowing air or inert gases. Selected unreacted4connection or With4connection can be then directed to the oxidation in the gas phase in order to obtain the Maxim is correctly possible degree of transformation.

In yet another preferred embodiment corresponding to the invention of the method stage of the process includes the following process steps:

2α) crystallizing at least part of the methacrylic acid from the aqueous methacrylic acid,

2β), if necessary, rinsing crystallized methacrylic acid,

2γ) melting at least part of the crystalline methacrylic acid to obtain molten crystalline methacrylic acid as at least one product containing crude methacrylic acid.

Crystallization on technological operations 2α) can be well-known specialist methods such continuous or intermittent crystallization as dynamic or static crystallization, or a combination thereof, for example, crystallization from the melt, crystallization by cooling with scrapers, fractionated crystallization, layer-by-layer crystallization, the suspension crystallization, crystallization in a falling film and the like, or any combination of two or more of such ways, with the preferred crystallization from the melt. When crystallization from the melt is carried out in the framework of the relevant invention of the method, it is preferable that the crystallization was carried out in no man is e than one cycle of melting and crystallization. In a preferred embodiment, the crystallization from the melt in accordance with the invention, at least part of the melt crystallized methacrylic acid used for washing at least part of the crystalline methacrylic acid. Suitable methods are presented, for example, in WO No. 02/055469 A1, No. 99/14181, No. 01/77056 A1, U.S. patent No. 5504247, the main provisions which related to crystallization, are included in these materials as reference and form part of the description of the present invention.

At stage g) corresponding to the invention of the method containing methacrylic acid crude product obtained in stage C), is subjected to additional thermal separation to obtain pure methacrylic acid. The concept of pure methacrylic acid refers to methacrylic acid in the composition which contains less than 1 wt.%, in the preferred case, less than 0.8 wt.%, in a more preferred case, less than 0.5 wt.%, in a particularly preferred case, less than 0.3 wt.% impurities based on the total weight of methacrylic acid and impurities. Thermal separation in a preferred case is represented by distillation, when impurities are higher compared to the methacrylic acid boiling point remain in Cuba, and pure methacrylic acid in the preferred case, the selected level, R is palojenom above the level of the cube column. You can also select phase with methacrylic acid in the upper and/or lower part of the column. The impurities in the respective phases of methacrylic acid determine the possibility of assigning it to the corresponding invention of pure methacrylic acid. In the preferred embodiment corresponding to the invention of the method according to at least one containing methacrylic acid crude product is directed to the step g)includes the maximum of 95 wt.%, in a more preferred case, the maximum of 90 wt.% and in even more preferred case, the maximum of 85 wt.% methacrylic acid. For example, if the concentration of methacrylic acid in the organic phase obtained in accordance with the invention for operation 1α), does not meet this aspect of the invention, before the implementation of the method of thermal separation operations 1β) corresponding to the invention of a way you can bring the concentration to the desired value, for example, by adding or deleting, in the preferred case of removal, the component phases. This can be accomplished, for example, by adding intermediate operations division, for example, distillation to separate low-boiling or high-boiling components, filtering to remove solid impurities, crystallization, and similar operations. In another preferred embodiment, with the relevant invention of the method directed to the stage of method d) at least one containing methacrylic acid crude product was obtained by distillation or crystallization of the composition, containing at least 5 wt.%, in the preferred case, at least 10 wt.% and in even more preferred case, at least 15 wt.% hydrocarbons with carbon atoms from four to eight. Hydrocarbons with carbon atoms from four to eight in accordance with the invention can include any of these compounds as acetic acid, maleic acid, fumaric acid, Tarakanova acid, acrylic acid and formic acid, as well as aldehydes, ketones and unreacted4connection or With4connection.

In yet another preferred embodiment corresponding to the invention of the method directed to the stage of method d) at least one containing methacrylic acid crude product has a score of ARNA (American Public Health Association) in accordance with DIN ISO 6271 not less than 100, in the preferred case, at least 250, and even more preferred not less than 500. Figure ARNA, also called platinumblack indicator color or hue in Hazen, is a standard color detection solution or liquid in comparison with standard color is painted platinumblack solutions; typically it is used to determine the yellowness of the material with the higher value of the index ARNA corresponds to more intense yellow staining is aniu. A more detailed description of indicator ARNA presented in "The Measurement of Appearance, 2nd Ed., Richard S. Hunter and Richard W. Harold, Wiley, 1987, str and 214, as well as in the application for U.S. patent No. 7002035 B2, the main provisions of these works are included in this description by reference and constitute a part of the object of the present invention.

In yet another preferred embodiment corresponding to the invention of the method directed to the stage of method d) at least one containing methacrylic acid, the crude product includes methacrylic acid number in the range from 97 wt.% up to 99.7 wt.%, in the preferred case, the amount in the range of 97.5 wt.% up to 99.7 wt.%, in a more preferred case, the amount in the range from 98 wt.% up to 99.6 wt.% and in even more preferred case, the amount in the range of 98.5 wt.% up to 99.5 wt.%.

In a preferred embodiment for implementing the invention method on the process stage g) of methacrylic acid is separated from at least part of at least one containing methacrylic acid crude product by distillation, the pure methacrylic acid are selected from used for rectification column through the side conclusion. Containing methacrylic acid fraction can also be selected from the head and from the bottom of the distillation column.

Preferably, when p is and implement this option, corresponding to the invention of the method such rectification stage d) is carried out at a pressure in the cube in the range from 0.1 to 100 mbar, in the preferred case in the range from 0.5 to 90 mbar, in the preferred case in the range from 1 to 80 mbar and even more preferred in the range from 5 to 70 mbar, in the preferred case in the range from 10 to 50 mbar. These limits pressure below atmospheric pressure, allow distillation at lower temperatures, creating a milder process conditions and due to this, reduce the degree of oligomerization and polymerization of methacrylic acid, which can lead to increased output and saving energy and reducing consumption used in this polymerization inhibitor and/or stabilizer.

Preferably also, when you implement this option, corresponding to the invention of the method such rectification stage d) is carried out at a temperature in Cuba in the range from 40 to 200°C, in the preferred case in the range from 40 to 180°C, more preferred in the range from 40 to 160°C, more preferred in the range from 50 to 140°C, more preferred in the range from 50 to 130°C, more preferred in the range from 50 to 120°C, even more preferred is the case in the range from 50 to 110°C and in the most preferred case in the range from 50 to 100°C. In a particularly preferred aspect, the variant according to stuudio the invention, a method of rectification on the process stage d) is carried out at a temperature in the cube less than 90°C.

Preferably also, when in this embodiment corresponding to the invention of the method of the distillation column is from 0 to 10 theoretical plates per meter, in the preferred case from 0.5 to 8 theoretical plates per meter, in the preferred case from 1 to 7 theoretical plates per meter, in the more preferred case from 1.5 to 6 theoretical plates per meter. Theoretical plate in the distillation process is a hypothetical zone or area where the liquid and vapor phase shepherd substance are in equilibrium with respect to each other. The greater the number of theoretical plates, the better the efficiency of the separation process. The concept and methodology of calculation of theoretical plates are well known to the specialist. Because the actual physical plates, partitions or shelves or similar structural elements as layers nozzles, for example, consisting of Raschig rings or other structured packings, rarely correspond to the state 100%efficient equilibrium, the number of actual plates is usually greater than the number of required theoretical plates.

Preferably, when the part corresponding to the invention method, the load factor of the liquid to the distillation column is in the range from 0.5 to 10 m3/m2h, in the main the entrusted case in the range from 1 to 5 m 3/m2h, in the preferred case in the range from 1.5 to 3 m3/m2h, even more preferred in the range from 1.7 to 2.5 m3/m2including In particular, above the lateral output of the rectifying column, this value remains almost unchanged, since the column is mainly concentrated methacrylic acid. The load fluid is determined by the properties of the product and the selected range of values of pressure and temperature, in this case, for example, a higher load requires a higher pressure, and therefore a higher temperature in the cube.

In particular, preferably, when in accordance with the invention at a stage d) selection of pure methacrylic acid is carried out at the height between the bottom quarter top quarter of the distillation column, in the preferred case, this use side output. This provides improved separation from impurities with higher and lower boiling points compared with methacrylic acid. Other factions of methacrylic acid can also be obtained at different levels in height, and from the head of the column and/or from a cube. Such other fraction of methacrylic acid, even when they contain a lot of impurities that cannot be considered relevant to the invention of pure methacrylic to what slotow, you can find the application on the following operations in chemical processing where there is no need to use very pure methacrylic acid, or where separation from impurities can without difficulty carry on later stages, for example, when we get further final or intermediate target product processing is significantly different in melting point or boiling point or solubility present in it from impurities. Examples of such obtained is further processed products are esters of methacrylic acid.

In one embodiment corresponding to the invention, a method may be preferable that the inflow to the step d) at least one containing methacrylic acid crude product was met hydrodynamic resistance when entering the rectifying column or thereafter. In accordance with the invention coming on stage g) containing methacrylic acid crude product can be submitted to the cube of the distillation column, in its head part, or to any other point between the cube and the head part of the distillation column. In accordance with the invention, preferably, when arriving in a distillation column containing methacrylic acid crude product does not arrive in a convoy across the side input or inputs for pure methacrylic acid directly. In particular, preferably, when containing methacrylic acid CBM product passes through one or more side inlets. In this case, for example, this may occur due to physical splashing through hydrodynamic resistance, which coming into the string stream containing methacrylic acid crude product in the preferred case meets the obstacle, fractions in the direction of the main stream entering the column containing methacrylic acid crude product in the preferred case, at an angle ranging from 60° to 120°, more preferred case, at an angle in the range from 70° to 110°, more preferred case, at an angle ranging from 80° to 100°, in the preferred case at an angle in the range from 85° to 95°, in the most preferred case, the flow resistance is as closely as possible to the perpendicular direction. In accordance with this, the angle at which the stream containing methacrylic acid crude product meets an obstacle for creating hydrodynamic resistance, in the preferred case represents the angle formed by the main direction of the flow entering the column containing methacrylic acid crude product, with a deviation from the main direction of flow OK the lo ±30°. This can be achieved by using the additional inputs in the form of pipes, outlets and nozzles, including well-known specialist in fixed and/or rotary inputs. If the containing methacrylic acid CBM product passes through the side input in the form of a spray nozzle, it is desirable that the hole of the spray nozzle formed an angle in the range from about 60° to about 120°, in the preferred case in the range from about 70° to about 110°, more preferred in the range from about 80° to about 100°, more preferred in the range from about 85° to about 95°. Hydrodynamic flow resistance can be formed, for example, dividing wall, serving to separate the side input side output. In the preferred embodiment corresponding to the invention of the method of the distillation column is a column with hydrodynamic resistance created by the so-called dividing wall that separates at least one side input for containing methacrylic acid cubic product from at least one side of the output corresponding to the invention of pure methacrylic acid. The dividing wall of its kind in the preferred case is within at least three theoretical tar the lock, located above at least one of the at least one lateral input and at least one side of the conclusion, in the preferred case, the top of them, and within at least three theoretical plates below at least one of the at least one lateral input and at least one side of the conclusion, in the preferred case, the bottom of them.

You can also prevent the mixing of the incoming product with pure methacrylic acid by the arrangement of the lateral input is not at the level where the nozzle output, or by combining this arrangement with a device for creating hydrodynamic resistance. If at least one containing methacrylic acid CBM product obtained in process stage b)is introduced into distillation column in the field from the first to the fifth theoretical plates below the side of the conclusion, in appropriate cases, the dividing wall can be a design element of the distillation column. Accordingly, in another preferred embodiment corresponding to the invention of the method according to at least one containing methacrylic acid crude product obtained in process stage b)can be fed into distillation column between the first and fifth theoretical plates below Boko is on output. In yet another preferred embodiment corresponding to the invention of the method according to at least one containing methacrylic acid crude product obtained in process stage b), submit to the cube of the distillation column.

In accordance with the invention method, preferably, when taken through the side output of the rectifying column, the number of pure methacrylic acid at a specific time interval ranges from 40 to 80 wt.%, in the preferred case from 50 to 80 wt.%, in the preferred case from 60 to 80 wt.% from the number obtained in process stage b) containing methacrylic acid crude product received in the distillation column within the same time frame. The rest of methacrylic acid that is incorporated into an appropriate number containing methacrylic acid crude product obtained in process stage b) and submitted to distillation column in the same corresponding time interval, in the preferred case is withdrawn from the head part and/or from the rectifying column bottom. Within the invention method can also perform thermal separation stage of the process g) in the presence of decolorizing active substances. Formulated active substance in General, when enaut to improve the color of the product resulting from at least partial removal and/or degradation of physical and/or chemical means, at least one colored impurities and/or at least one source product for the formation of colored impurities. Impurities that may be present during the implementation of the method of the invention include aldehydes and organic acids, for example, formaldehyde, acetaldehyde, acrolein, methacrolein, propionic aldehyde, n-Butyraldehyde, benzaldehyde, furfural, CROTONALDEHYDE, acetic acid, formic acid, propionic acid. However, in accordance with the invention can find application in any well-known specialist and seem suitable decolorizing active substances. Formulated active substances can be, for example, substances that can adsorb or which adsorb colored compound and/or starting materials for the formation of colored compounds. Examples of such materials are activated carbon, ion exchange resins, zeolites, silicates, aluminates, molecular sieves and the like; they can be in any suitable form, for example, in the form of powders, granules or balls. It may also include other well-known in this field of active decolorizing agents, for example, it can be compounds that bind impurities, in particular, aldehyde impurities, for example, such amino compounds as bonds alkylamines, arylamines, arylalkylamine, alkanolamine, hydrazines and proizvodi the e hydrazines. Formulated active substance in the preferred case, take in the amount ranging from 0 to 5 wt.%, in the preferred case in the range from 0.0001 to 3 wt.%, in the preferred case in the range from 0.0005 to 3 wt.%, in a more preferred case, in the range 0.005 to 2 wt.% and in even more preferred in the range from 0.001 to 1 wt.%, in the most preferred case, in the amount of from 0.001 to 0.5 wt.%.

If in accordance with the invention is active decolorizing substance, it is preferable that the active decolorizing substance was a derivative of hydrazine, in the preferred case, this salt aminoguanidine. In particular, in the preferred embodiment corresponding to the invention of a way salt aminoguanidine represents the bicarbonate aminoguanidine, also called acid carbonate aminoguanidine. If in accordance with the invention is active decolorizing substance, it is preferable that the active decolorizing substance was added

A) to not less than one containing methacrylic acid crude product obtained in process stage a) before thermal separation stage of the process g), or

B) during thermal separation stage of the process g).

If active decolorizing emesto added in accordance with A) to not less than one containing methacrylic acid crude product, obtained at the stage of the process), before thermal separation at the stage corresponding to the invention of the process g), in the preferred case, it is added after removal of the cubic product from the apparatus, which held the stage), before feeding into the machine which hosts the stage d). Such addition may also be carried out simultaneously with the filing not less than one containing methacrylic acid crude product obtained in process stage b), the stage of the process of thermal separation g), for example, by adding decolorizing of the active substance at the point of submission of at least one containing methacrylic acid crude product obtained in process stage b), the stage of the process of thermal separation g). If the formulated active substance is added in accordance with B) in the course of thermal separation stage of the process d), it can be added at any seem specialist suitable point, for example, by filing in the head part or the cube distillation column or a distillation column or side entry, in a preferred case, the column at this time is in working condition.

To prevent oligomerization and/or polymerization and other reactions of methacrylic acid during such thermal operations, as PR is dostavlennya above, you can add at least one inhibitor and/or stabilizer in the course corresponding to the invention process. Addition of an inhibitor and/or stabilizer can be performed at any stage of the process, but in the preferred case, the addition is conducted before implementation or during the implementation of at least one of the stages 2α) or g), or the same way or at the same time as the above addition of decolorizing active substances. In the known methods, in accordance with which the product output in the form of vapors from the head of the column, the product falls again to completely stabilize the addition of the stabilizer and/or inhibitor after exiting the column, that is, the stabilizer should be added to the column and distilled product. In accordance with the invention method, the addition of an inhibitor and/or stabilizer can be carried out in a column, for example, flamerobin at the head of the column when implementing operations 1β) or stage d), in the preferred case in stage g), or through the bottom entry in the column, and the lower input may be located above, below or on the same level as side conclusion for pure methacrylic acid. A particular advantage of the relevant invention of the method is that the amount of stabilizer and/or inhibitor in pure m is acrylaway acid, taken through the side outlet, in particular, through the side outlet for the liquid phase, for example, for selection of methacrylic acid in liquid form, can be adjusted by addition of a stabilizer and/or inhibitor in the head of the column, and therefore no need for the addition of the stabilizer and/or inhibitor to obtain pure methacrylic acid. This is due to the fact that the column is almost evenly loaded with liquid on its height, in particular, in stage d) corresponding to the invention of the method, at the same time across the column prevails a high concentration of methacrylic acid. Therefore, in the framework of the relevant invention of the method may be unnecessary add stabilizer/inhibitor to receive the column of product. In accordance with this preferred aspect relevant to the invention of this method is the addition of the stabilizer and/or inhibitor in the head of the column, in the preferred case through the phlegm in the head of the column. In accordance with the invention can also be addition or the addition of additional quantities of the stabilizer and/or inhibitor to methacrylic acid withdrawn from the column at stage d) corresponding to the invention method. Suitable stabilizers and inhibitors known for the specialist, these include, for example, hydroquinone, onomatology ether of hydroquinone, para-nitrosophenol, para-methoxy-phenol or phenothiazines.

Preferably, when the invention method, the stage of the process g) of not less than one obtained in process stage b) containing methacrylic acid crude product precipitates less than 5 wt.%, in the preferred case, less than 1.5 wt.% impurities, in a particularly preferred case does not precipitate impurities other than methacrylic acid. Precipitation of such impurities as polymeric and/or oligomeric methacrylates, among other reasons, cause breaks in the reactor, for example, mandatory treatment and/or unlocking of the reactor, so that the impurities should be minimized. It takes place in the implementation process as a continuous circuit, as well as on intermittent, but most of all it relates to continuous processes.

In the preferred embodiment corresponding to the invention, a method for the continuous scheme works at least stage of the process g). In accordance with the invention does not exclude work on intermittent, for example, with the introduction of process batches of raw materials, but preference will be given to work on the continuous scheme. Work on the continuous scheme is a process, in accordance with to the that at least obtained at the stage of the process) containing methacrylic acid crude product is continuously fed into process stage d), and pure methacrylic acid and other phases of methacrylic acid, if they are continuously sampled with the process stage g).

The invention relates also to a device for producing methacrylic acid, which comprises at least listed further components that are in the current contact between them:

A1) module oxidation in the gas phase,

B1) absorption module

B1) the separation module and

G1) the cleaning module;

when the cleaning module includes at least one distillation column, the distillation column has at least one lateral outlet for pure methacrylic acid.

The concept of "current contact" in this context means that the working modules are interconnected so that the working phase, which can be a liquid, vapor, gas, supercritical fluid, or any other mobile phase, was able to move from one module in at least one other module. This can be achieved, for example, when the forward movement of the tubing or piping is made of, for example, from such resistant to the reagents and the conditions of the process materials, such as stainless steel or glass or other well-known specialist of suitable materials, however, can be used and an intermediate tank in the form of qi is the turn on wheels or vaults or tanks, located between the modules. When is gas and it should remain in a gaseous state, preferably to be applied, keeping the temperature below the dew point for that gas. If there is fluid in the preferred case, the flow of this fluid is carried out at such a temperature that exceeds the temperature of crystallization and/or the temperature of deposition of the liquid and/or present in the liquid component. This can be achieved by insulation and/or heating a corresponding feed gas or the respective fluid communications. All reactors, columns and other components of the device in the preferred case is made from a material which is resistant to the action of the Regents and to such process conditions, such as temperature and pressure to which they are exposed.

Module oxidation in the gas phase in the preferred case includes at least one reactor suitable for carrying out reactions in the gas phase, in particular, it represents the reactor to work under pressure, in the preferred case, it is a reactor with lots of tubes, for example, is a shell-and-tube reactor, it may be also at least one plate of the reactor and/or at least one reactor with a fluidized bed, the ri preferable reactor with multiple tubes. Particular preference is given to at least one reactor with many pipes, in which the oxidation catalyst is at least one tube in the preferred case the tube is filled or coated with catalyst, in the preferred case, they are filled with oxidation catalyst. Oxidation catalysts, which in accordance with the invention are preferred, were presented above in connection with the corresponding description of the invention method. The materials of the reactor should be sustainable and in the preferred case, inert to the reagents and the conditions inside the reactor. Suitable reactors can be supplied, for example, by MAN DWE GmbH, Deggendorfer Werft, Germany, or IHI Corporation, Japan, and their selection refers to the overall competence of the specialist in this field.

At the two-stage oxidation in the gas phase module oxidation in the gas phase may comprise at least two reaction zones, each of which contains an oxidation catalyst. These at least two reaction zones may represent at least two reaction zones in a single reactor or in at least two reactors. The oxidation catalyst in the first reaction zone in the preferred case is a catalyst for the oxidation of at least one4connection, in the preferred case, isobut the Lena and/or tert-butanol, to methacrolein, and the oxidation catalyst in the second reaction zone in the preferred case is intended for oxidation methacrolein to methacrylic acid. Suitable catalysts were presented above in connection with the corresponding description of the invention process.

In a preferred aspect relevant to the present invention, the hardware module for carrying out the oxidation in the gas phase is suitable at least one supply line for at least one source of an oxidant, in the preferred case of oxygen, in the preferred case of air, and at least one feed line for water and/or steam. If the module for oxidation in the gas phase includes at least a first oxidation zone, the apparatus may include at least one supply line for at least one source of an oxidant and at least one supply line for water and/or steam for each oxidation zone. The apparatus may also include a supply line for diluent such as nitrogen, argon and/or carbon dioxide, in the preferred case is nitrogen or carbon dioxide, for example containing carbon dioxide recirculating gas from the catalytic combustion module or from the module thermal incineration. The corresponding supply line must be made of a material, the cat is who is resistant to the reagents and the conditions of their work, for example, stainless steel or glass. In a preferred constructional variant oxygen, diluent and water is fed into the material flow With4connection before entering it into the appropriate reactor so that the reactor has already been reported the mixture.

In the preferred embodiment corresponding to the invention perform hardware absorption module is a module rapid cooling (quenching module). Preferably, when methacrylic acid is contained in the output of the catalytic reaction zone, condensed in the absorption module in the form of a solution, in the preferred case in the form of an aqueous solution containing methacrylic acid as the main product of oxidation. Unreacted methacrolein can also be separated in the absorption module and, if necessary, is directed back into the zone of oxidation in the gas phase for further transformation. Absorption devices suitable for use in the relevant invention apparatus, known to specialists in this field. Stage b) of the invention method in a preferred case is carried out in absorption module.

In a preferred embodiment corresponding to the invention of the device separation module includes

VA) extraction module and

VA) at the very the least one primary distillation column, in fact, at least one primary distillation column equipped with at least one placed at the bottom of the pipe for withdrawal of fluid between at least one distillation column.

In this embodiment corresponding to the invention of the device for the absorption module extraction module. Containing methacrylic acid aqueous solution formed in the absorber module is sent to the extraction module, which is fed into an organic solvent in which the solvent extracts in the preferred case, the main part of methacrylic acid. Preferably, when the organic solvent is almost completely immiscible with water and then formed at least partially from methacrylic acid aqueous phase containing methacrylic acid in the organic phase. Details relating to organic solvents, which are preferred above during the description stage of the process 1α).

Not less than one first distillation column corresponding to the invention the separation module in a preferred case is designed so that it meets the operation 1β) corresponding to the invention process. The first distillation column separation module and at least one distillation the th column of the cleaning module can be directly connected to each other so that to containing methacrylic acid CBM product from the first distillation column module separation was directly transferred to a distillation column module cleanup. Before these two columns, between, or after them can also be fitted with an additional apparatus. Such additional components may be selected from among well-known expert in this field, if he thinks fit; this unit may be at least one absorber, a mold, an extractor, a filter device for heating, cooling and/or rinsing. In the preferred embodiment corresponding to the invention the device cube first distillation column separation module is connected to the corresponding line with tube feeding at least one distillation column of the cleaning module. Enter in at least one distillation column of the cleaning module can be accessed through the side pipe, through the input device in the head part, for example, in the phlegm of the product in the head part after condensation, or through the supply line in the cubic part.

In another preferred embodiment corresponding to the invention of the device

the separation module includes

VB) node crystallization and

VV) if necessary, wash the site

In accordance with this variant soo is relevant to the invention the device for absorption of the module followed by the module crystallization and, if necessary, wash the node module crystallization obtained in the absorption module aqueous solution of methacrylic acids in General is cooled so that was at least partial crystallization of methacrylic acid. The resulting slurry can then be pumped to the washing site, for example, in a wash column, where the solid crystals at least partially separated and washed, in order to at least partially remove impurities. At least a portion of the crystals, which if necessary could be washed, melted and at least a portion of the molten portion or sent to the following element of the device, or it is used as a drilling fluid or apply on these two assignments. You can also submit at least part of the crystal in the module crystallization as a seed for crystallization. Structural element for receiving the melt can also be included in the separation module. Device for melting can be embedded in not less than one unit of crystallization or in the module or it may be a separate structural element. Module crystallization can be any well-known specialist module crystallization, if he valued them as suitable for crystallization of methacrylic acid containing from crude methacrylic acid aqueous solution. Suitable modules crystallization pic is alauda Sulzer Chemtech AG, Switzerland, or Niro Process Technology B.V., the Netherlands. Examples of suitable modules crystallization, washing modules and structural components to obtain the melt are given in cited in connection with the description of the stages of the process 2α) literature.

Corresponding to the invention the device may also include additional components between the absorption module and module extraction or module crystallization, such as distillation columns, in the preferred case in the form of distillation columns, intended for at least partial separation of low-boiling components, in the form of a filter for separating insoluble impurities and/or by-products included in the product emerging from the absorption module and/or of the cooling module, and/or of the heating module. In the preferred structural embodiment, the distillation column for low-boiling components and filter, if necessary, establish in the course of the stream for rapid cooling module and before extraction module.

In a particularly preferred embodiment corresponding to the invention the device is not less than one distillation column cleaning unit has a lateral outlet for the output of pure methacrylic acid. This side bend is located at a height so that he was between the top and bottom Colo the us, with its location on the height selected depending on the length of the column and the desired purity and the desired composition of pure methacrylic acid, and the amount and kind of impurities included in the supply convoy of the mixture. The closer the side branch to the top of the column, the more low-boiling impurities may be contained in the pure methacrylic acid. The closer lateral drainage to the cube of the column, the more high-boiling impurities may be contained in the pure methacrylic acid. In accordance with the invention, pure methacrylic acid may contain small amounts of impurities, as described above in connection with the corresponding description of the invention method. At least one distillation column of the cleaning module may also include an output line in the head of the column and/or lateral drain in the bottom part of column to output the respective phases of methacrylic acid. These phases of methacrylic acid are considered relevant to the invention of pure methacrylic acid in the case when they contain the above small amounts of impurities. These phases of methacrylic acid, in particular when they contain significant amounts of impurities than clean in accordance with the invention, methacrylic acid, can find application in the processing for other p is the FL. In particular, they can be used to obtain esters of methacrylic acid.

Unreacted methacrolein can be allocated in any of the absorption module, an extraction module, at least one primary distillation column module separation, crystallization module, the cleaning module or any other above mentioned element of the device and, if necessary, it can be re-directed to the module oxidation in the gas phase for subsequent transformation.

In the preferred embodiment corresponding to the invention the device is not less than one distillation column in the cleaning module is a distillation column. Preferably, when distillation columns include from 0 to 10 theoretical plates per meter, in the preferred case from 0.5 to 8 theoretical plates per meter, in the preferred case from 1 to 7 theoretical plates per meter and in the more preferred case from 1.5 to 6 theoretical plates per meter. Because the actual physical plates, partitions or shelves, for example, bubble cap plates, or similar structural elements as LUT nozzles, for example, consisting of Raschig rings or other structured packings, rarely correspond to the state 100%efficient equilibrium, the actual colaterales is usually greater than the number of required theoretical plates. The number of real plates, depending on the type of plates, can be calculated by a specialist or it can be determined by conducting simple experiments, for example, by using the comparison engine chlorobenzene-ethylbenzene in accordance with Chemie-Ingenieur-Technik, Vol 59, Issue 8, str-653.

Containing methacrylic acid crude product coming from the separation module, can be directed in at least one distillation column cleaning unit through the pipe at the head of the column, in the bottom part or in the middle part of the column. In the preferred embodiment corresponding to the invention the device of the distillation column includes at least one entry in the middle part for not less than one containing methacrylic acid crude product. This side input can have any structural features that correspond to the flow in the column containing methacrylic acid crude product, it can be one or more pipes, tubes, outlets and nozzles that can be fixed and/or rotary. The height on which side is the input, you can choose depending on many factors, for example, from the height of the side output for pure methacrylic acid, as well as on temperature and/or composition containing methacryloylamido raw product input to a distillation column module cleanup.

In yet another preferred embodiment corresponding to the invention the device of the distillation column is a column in which to create the hydrodynamic resistance, in the preferred case, this is the so-called separation wall (the divisor). In particular, this option is preferred in the case when containing methacrylic acid crude product is fed into the distillation column using one or more side inlets, in the preferred case, this design feature serves to distinguish this side input or these lateral inputs from one or more side outlets and to prevent mixing with the incoming column of the product with pure methacrylic acid selected from the column. In accordance with the invention, it is preferable that the effect of hydrodynamic resistance arose in the result of a blow to the separation wall coming into the column containing methacrylic acid crude product, in the preferred case, the direction of the hydraulic shock corresponds to the direction of the main stream entering the column containing methacrylic acid crude product, in the preferred case, this occurs at an angle ranging from 60° to 120°, more preferred CL the tea at an angle in the range from 70° to 110°, in a more preferred case, at an angle ranging from 80° to 100°, and even more preferred case, at an angle in the range from 85° to 95°, in the most preferred case, the flow resistance is as closely as possible to the perpendicular direction. If a touch input is a spray nozzle, it is desirable that the hole spray nozzle formed an angle in the range from about 60° to about 120°, in the preferred case in the range from about 70° to about 110°, more preferred in the range from about 80° to about 100°, more preferred in the range from about 85° to about 95°. The concept of the column with a dividing wall refers to the column that includes fixed in the longitudinal direction with respect to the column wall or plate that at least partially, but not completely, divide the column into two sections along its longitudinal axis. The dividing wall can reach the walls of the column and is attached thereto, to the top and/or bottom of the column, while in the preferred case, the dividing wall is not attached to the column along its entire length. Columns with dividing walls, also called divided by columns, well-known specialist in this field and can be purchased commercially. The length of the section is long wall in the preferred case is within at least three theoretical plates, located above at least one of the side inputs (feed nozzle for feeding to the column containing methacrylic acid crude product and the side output for pure methacrylic acid. In particular, preferably, when the separating wall is held within not less than three theoretical plates above at least one side of the input and at least one side of the conclusion, in the preferred case, the top of them, and in the preferred case, within at least three theoretical plates below at least one of the at least one lateral input and at least one side of the conclusion, in the preferred case, the bottom of them. If at least one containing methacrylic acid crude product is fed into the distillation column in the range from one to five or more theoretical plates below the lateral output, using a distillation column with a dividing wall is not always appropriate.

The invention relates also to a corresponding method, according to which the process proceeds in accordance with the invention device.

The invention relates also to the pure methacrylic acid obtained corresponding to the invention method.

At that time, as stage d) of the corresponding image is meniu method and features of the hardware design, concerning the final stage of purification of components of g corresponding to the invention the device includes the above description of the methacrylic acid obtained by the catalytic oxidation in the gas phase source With4connection, this stage and the corresponding component is also suitable for purification of methacrylic acid obtained in such other ways as acetonecyanohydrin process, as well as for purification of acrylic acid, in particular for the purification of acrylic acid obtained by the oxidation in the gas phase such C3connection as propylene and/or acrolein.

The invention relates also to a method for producing esters of methacrylic acid, including stage of the process:

A) obtaining pure methacrylic acid corresponding to the invention by a method and

B) esterification of pure methacrylic acid.

Corresponding to the invention the esters of methacrylic acid in the preferred case, correspond to the formula [CH2=C(CH3)C(=O)O]n-R; they can be obtained by the esterification of methacrylic acid with an alcohol of the formula R(OH)mwhere

n and m denote an integer from 1 to 10, in the preferred case from 1 to 6, more preferred from 1 to 5, more preferred from 1 to 4 and in the more preferred case from 1 to 3 and

R is chosen from the group on the expectation of a linear or branched, saturated or unsaturated, aliphatic or aromatic, ring or having an open chain hydrocarbons and linear or branched, saturated or unsaturated, aliphatic or aromatic, ring or having an open chain hydrocarbons, whose members are heteroatoms, for example, alkyl, hydroxyalkyl, aminoalkyl, other containing nitrogen atoms and/or oxygen balances, glycols, diols, triola, bisphenola, residues of fatty acids, with R in the preferred case, means methyl, ethyl, sawn, ISO-propyl, boutelou, in particular, n-boutelou, isobutylene, hydroxyethylene, the preferred case 2-hydroxy-ethyl, and hydroxypropyl, in the preferred case of 2-hydroxy-sawn or 3-hydroxypropyl group, 2-ethylhexyloxy, isodecanol, tikokino, isobornylic, benzyl, 3,3,5-trimethylcyclohexanol, saariluu group, dimethylaminoethanol, dimethylaminopropanol, 2-tert-butylaminoethyl-ing group, ethyldiglycol, tetrahydrofurfuryl, butyldiglycol group, the rest of methoxypolyethyleneglycol-350, methoxypolyethyleneglycol-500, methoxypolyethyleneglycol-750, methoxypolyethyleneglycol-1000, methoxypoly-glycol-2000, methoxypolyethyleneglycol-5000, allyl residue, etilenglikolevye, diethylenglycol, trie the ilerlemeyi residue, the rest of polyethylene glycol 200, polyethylene glycol 400, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, glycerin, Durmanov the remainder, the remainder of ethoxylated bisphenol a, the remainder ethoxylated ten ethylenoxide structural units of bisphenol a; the remainder of trimethylolpropane, the remains of such ethoxylated fatty alcohols with a number of carbon atoms from sixteen to eighteen, as, for example, ethoxylated twenty-five ethylenoxide structural units; 2-trimethylaminoethyl group.

Esters of methacrylic acid can also be derived from methyl methacrylate and other well-known specialist of ways, for example, in the interesterification. Another possible way to obtain derivatives of esters with hydroxyl groups represented by the interaction corresponding to the invention of methacrylic acid in the reaction to the disclosure of the cycle, flowing with the corresponding cycle involving oxygen atom, for example, epoxide, in particular with ethylene oxide or with propylene oxide.

The invention relates to esters of methacrylic acid, obtained relevant to the invention method. In the preferred case, the esters of methacrylic acid correspond to the formula [CH2=C(CH3)C(=O)O]n-R, where R and n have the above significance. The preferred methacry innymi esters include alkyl methacrylates, in particular, methyl-, ethyl-, propyl-, isopropyl-, butyl-methacrylates, in particular, n-butyl-, isobutyl-, sec-butylmethacrylate, in particular, n-butyl methacrylate, isobutylacetate, hydroxy methacrylate esters, for example, hydroxyethylmethacrylate, in the preferred case of 2-hydroxyethyl-methacrylate, and hydroxypropylmethacrylate, in the preferred case of 2-hydroxy-propylbetaine or 3-hydroxypropylmethacrylate, as well as special methacrylate esters, ethyl methacrylate, 2-ethylhexylacrylate, isabellemadelinet, cyclohexylmethyl, isobornylacrylat, bezelmaterial, 3,3,5-trimethyltin-hexyllithium, sterilisability, dimethylaminoethylmethacrylate, diethylaminoethylmethacrylate, 2-tert-butyl-aminoacylation, methacrylate of ethyldiglycol, tetrahydrofurfurylamine, methacrylate of butyldiglycol, methacrylate methoxy-polyethylene glycol-350, methacrylate of methoxypolyethyleneglycol-500, methacrylate IU-Toxicological-750, methacrylate of methoxypolyethyleneglycol-1000, methacrylate of methoxypolyethyleneglycol-2000, methacrylate of methoxypolyethyleneglycol-5000, allyl-methacrylate, methacrylic acid and ethoxylated (e.g., with a degree of amoxilonline 25) fatty alcohol with the number of carbon atoms from sixteen to eighteen, chloride trimethylammoniumchloride, dimetil is tons of ethylene glycol, the diethylene glycol dimethacrylate, dimethacrylate of polyethylene glycol 200 dimethacrylate of polyethylene glycol 400, dimethacrylate 1,3-butanediol, dimethacrylate of 1,4-butane-diol dimethacrylate 1,6-hexanediol, glycerol dimethacrylate, diabetesdetailed, dimethacrylate of ethoxylated bisphenol a dimethacrylate of ethoxylated bisphenol a (e.g., with a degree of amoxilonline 10), trimethacrylate of trimethylolpropane, with particular preference given to methyl methacrylate, butylmethacrylate and hydroxy esters of methacrylic acid.

The invention relates also to a method for polymethacrylates, including stage of the process

i) obtaining pure methacrylic acid corresponding to the invention by a method and

ii) radical polymerization of pure methacrylic acid, if necessary in the presence of monomers which copolymerized methacrylic acid.

The polymerization is no particular restriction; it can be performed in any well-known specialist and assessed as suitable manner, for example, as described in U.S. patents№5292797, №4562234, №5773505, №5612417, №4952455, №4948668, №4239671. The preferred methods of polymerization represented by the radical polymerization initiated by initiators which decompose into radicals under the conditions of polymerization, while the floor is Marisela in the preferred case is a polymerization in solution or emulsion polymerization, in the preferred case, the polymerization in aqueous solution.

Examples of comonomers that can copolymerizate methacrylic acid, are acrylamide and methacrylamide, such esters of acrylic acid and other esters of methacrylic acid as methyl acrylate, acrylate, propylacetate or butyl acrylate, ethyl methacrylate, papermaterial or butylmethacrylate, and acetates such as vinyl acetate, styrene, butadiene and Acrylonitrile. Most preferably, when we are talking about only one monomer selected from the group consisting of styrene, butadiene, Acrylonitrile, butyl acrylate, vinyl acetate, methyl acrylate.

The polymerization can also be carried out in the presence of one or more funds for the education of a mesh structure. In accordance with the invention, the preferred means for the formation of the mesh structure are compounds with at least two unsaturated ethylene groups in one molecule, compounds with at least two functional groups that can react with functional groups of the monomers in the reaction scheme for the condensation reaction of accession or reactions to the disclosure of the cycle, and connection, which is composed of at least one ethylene unsaturated group and at least one functional group which can reah is encoded with functional groups of the monomers in the reaction scheme condensation, the reactions of addition or reaction to the disclosure of the cycle, or the cations of polyvalent metals.

The invention relates also to the polymethacrylates received relevant to the invention method.

The invention relates also to a method for producing esters of polymethacrylic acid, including stage of the process

i) obtaining esters of methacrylic acid corresponding to the invention by a method and

ii) radical polymerization of esters of methacrylic acid, if necessary in the presence of monomers which can copolymerisate with esters of methacrylic acid.

The above details relating to the polymerization of methacrylic acid, retain their value and for polymerization corresponding to the invention esters of methacrylic acid.

The invention relates to esters of methacrylic acid, obtained relevant to the invention method.

The invention relates also to the use of pure methacrylic acid obtained corresponding to the invention method, or to the use of esters of methacrylic acid, obtained relevant to the invention method, composition of fibers, foils, lacquers, coatings, materials for producing molded bodies, molded bodies, additives for paper production, additives to the skin, flocculants, water-soluble polymers, for the teachings of methacrylic anhydride and additives for drilling fluids.

The invention also relates to fibers, foils, lacquers, coatings, materials for producing molded bodies, molded bodies, additives for paper production, additives to the skin, flocculants, water-soluble polymers, methacrylic anhydride and additives for drilling muds, which are based on pure methacrylic acid obtained corresponding to the invention method, or the esters of methacrylic acid, obtained relevant to the invention method.

The invention in more detail is illustrated in the following schemes and examples, which may not be used to limit the scope of the claims.

Schema

Figure 1 shows schematically the apparatus for producing methacrylic acid in the two-stage oxidation in the gas phase from the separation module, comprising the extraction module and the first distillation column, while the distillation column of the cleaning module designed as a distillation column with a dividing wall and side conclusion for pure methacrylic acid.

Figure 2 shows schematically another embodiment of the second distillation column for cleaning module, which is designed as a distillation column without a separating wall with a side entry below the lateral output for pure methacrylic acid is.

On figa and figb schematically shows the angles that contains crude methacrylic acid phase hits in a dividing wall distillation column with a dividing wall.

In accordance with figure 1 is4connection as isobutylene and/or tert.-butanol, together with air and steam is injected in the form of material flow 1 in the first reaction tube 2 with a diameter of 25 mm and a length of 2 m, a heated salt bath 4. In the reaction tube 2 this stream passes first through the inert zone 24. Then through the first oxidation catalyst 25 is in at least partial oxidation to methacrolein with the formation of the first phase oxidation, and then passes through another inert zone 26. After this first phase oxidation is directed to the second reaction tube 3 of the same construction, and the reaction tube 2, here it passes through the inert zone 27, and then through the second oxidation catalyst 28, where methacrolein at least partially oxidized to methacrylic acid, and then passes through another inert zone 29 and forms containing methacrylic acid second phase oxidation 5. The gas phase 5 crude methacrylic acid then passes through the tower for rapid cooling 6 where it is condensed with the formation of an aqueous solution of crude methacrylic acid 7. Neko is that low-boiling compounds, includes in the preferred case, methacrolein and/or unreacted4connection can be withdrawn through the side outlet 8 at the head of the column. Used for rapid cooling substance may be returned to the process for reuse in the column for rapid cooling line 30. Phase 7 aqueous methacrylic acid then make a column for distillation of low-boiling products 9, where such low-boiling 10, such as acetone and methacrolein, separated at the head of the column. The resulting aqueous solution of methacrylic acid 11 is withdrawn from the cube columns 9 and extracted with methacrylic acid and its transfer into the organic phase in the extraction module 12. The resulting organic phase 13 methacrylic acid is then sent to a distillation column 14 (it is similar to the first distillation column corresponding to the invention the separation module 39, at the same time, despite the fact that the feed to the column 14 shows a lateral input of organic phase 13 may also be supplied in the head part or in cubic part of the column 14), where the separation of low-boiling compounds 15. After that containing methacrylic acid crude product 16 is sent to the column 17, in which he enters through the input 18. The input 18 is shown as a lateral entry, but the product can do and cubic h is here. Column 17 includes an effective separating plates (not shown) and has a dividing wall 31, which is located along the longitudinal axis of the column 17. In working condition jet methacrylic acid 14 enters the side of the column 17 so that at least part of the stream of methacrylic acid 14 was aimed at the separation wall 31. The addition of inhibitor and/or stabilizer can be at the top of column 17 through the supply line regulator 19. Phase pure methacrylic acid 20 taken through the side output 24. The input 18 and the output 24 is represented schematically to illustrate how the separation column at different zones. The dividing wall 31 normally have to pass through no less than three theoretical plates on each side (above and below) not less than one input 18 and output 24. Other phases of methacrylic acid 21, 22 are selected respectively from the head and from the bottom of column 17. These other faction methacrylic acid 21 and 22 can be used for other reactions with the purpose of their processing, for example, esterification with the formation of methyl methacrylate (diagram not shown). Distillation column 9, 14 and 17 in the preferred case are at the head of the reflux condensers 36 for return to the appropriate column of the low-boiling products. Although the separator module 3 shown in the form of extraction of the node 12 and the distillation column 14, the separator module 39 may also be provided in the form of node crystallization 40 and, if necessary, wash the column 41, and, if necessary, in the form of a melt 42, if used remote to melt.

In an alternative embodiment, the distillation column for the corresponding the invention, a cleaning module presents the column 32, shown in figure 2; it has no dividing wall. In the rest of the description column 17 in figure 1 applied to the column 32 in figure 2. Enter 33 for containing methacrylic acid crude product 16 shown in the form of a side-entry, but not excluded and enter in the cubic part. In this embodiment, without a separating wall input 33 is at least one theoretical plate below output 34 for pure methacrylic acid 20, typically an input carry from one to five theoretical plates below or by typing in the cubic part.

On figa shown the preferred angles that stream containing methacrylic acid crude product strikes the dividing wall 31 of the column. Coming to the column containing methacrylic acid crude product is sprayed upon impact of the separation wall 31 at an angle α. The angle α in the preferred case a main direction D of the stream entering the column containing methacrylic acid sirokopolosnie against the separation wall 31, in the preferred case, this angle is in the range from 60° to 120°, more preferred from 70° to 110°, more preferred case, the angle is in the range from 80° to 100°, more preferred case, the angle is in the range from 85° to 95° and in the preferred case, the stream is almost perpendicular to the dividing wall. The angle at which containing methacrylic acid crude product is found to break up into droplets with a dividing wall 31 in this image represents the angle formed by the main flow direction D relative to the dividing wall 31 with a possible deviation β of about ±30° from the main flow direction D. If a touch input 18 is a spray nozzle, as is schematically shown in figb, the angle of opening of the spray nozzle in the preferred case is in the range from about 60° to about 120°, more preferred in the range from about 70° to about 110°, even more preferred in the range from about 80° to about 100°, and even more preferred in the range from about 85° to about 95°.

Examples

Test methods

Platinumblonde number ARNA determined photometrically as described in application for U.S. patent No. 7002035 B2 method.

oxidation Catalysts

The oxidation catalyst 1 (the first oxidation catalyst) are obtained in accordance with example 1 of the application for European patent No. 0267556 A2. The oxidation catalyst II (the second oxidation catalyst) are obtained in accordance with example 1 of the application for European patent No. 0376117 A1.

Example 1

The process is carried out in the device corresponding to Fig 1, but differing from it in the fact that as distillation columns of the cleaning module instead of a column 17 use the column corresponding to figure 2 (column 32). Temperature salt baths of the first and second reaction pipes respectively 360°C for the first reactor and 300°C for the second reactor. Isobutylene (5 vol. %) are oxidized in two stages air (85 vol. %) with water (10 vol. %) with the formation of gaseous reaction product containing methacrylic acid. This reaction product is condensed in the column for rapid cooling and receive an aqueous solution of methacrylic acid, and then it is separated from low-boiling component in the first distillation column. Receive an aqueous solution of methacrylic acid, containing different from methacrylic acid components, are presented in table 1 (the total mass of these substances, including methacrylic acid, in amounts to 100 wt.%). Methacrylic acid is extracted from an aqueous solution of methacrylic acid n-heptane is, as described in the application for European patent No. 0710643 A1. The resulting solution of methacrylic acid in n-heptane contains different from methacrylic acid components, are shown in table 1 (the total mass of these substances, including methacrylic acid, in amounts to 100 wt.%). Then this solution is directed to distillation to remove low-boiling components with receipt containing methacrylic acid cubic product (crude methacrylic acid)containing different from methacrylic acid components, are presented in table 1 as crude methacrylic acid (the total mass of these substances, including methacrylic acid, in amounts to 100 wt.%). This contains methacrylic acid raw CBM product then served in a continuous mode to a distillation column with effective built-in dividers (4 plates per meter). This column operates at a temperature in the cube 78°C when the pressure in the head end of the column 24 mbar. To prevent undesired polymerization in the column formed in the phlegm add based on hydroquinone polymerization inhibitor. From the head and from the bottom of column select streams with a high content of methacrylic acid, which can be used for the esterification contained methacrylic acid with alcohols. Clean Makrelov acid composition of impurities, shown in table 1 (the amount of methacrylic acid, comprising the total weight given methacrylic acid is 100 wt.%), taken through the side of the output.

Table 1
ComponentsThe aqueous methacrylic acidExtract n-heptaneCrude methacrylic acidPure methacrylic acid
Water53 wt.%1500 ppm170 ppm80 ppm
n-Heptane-79 wt.%--
Propionic acid0.1 mass %0.08 wt.%120 ppm35 ppm
Acrylic acid0.5 wt.%0.3 wt.%420 ppm105 ppm
The furfural10 ppm 30 ppm70 ppm<5 ppm
Benzaldehyde1800 ppm800 ppm1300 ppm<5 ppm
Carbonyl compounds in the amount of1.2 wt.%1000 ppm1600 ppm<10 ppm
Storable5 wt.%0.15 wt.%0.4 wt.%<10 ppm
Non-volatile components1 wt.%800 ppm0.1 wt.%-
ARNA (Pt-Co)>1000>800>5004
ppm - millionths

An example of comparison of 1A

This example implementation is identical to example 1 except that methacrylic acid are shown in table 2 composition selected from the head of the rectifying column with effective separation is arch-shaped elements.

Example 2

The process is carried out in presented in figure 1 the device side input crude methacrylic acid and side output of pure methacrylic acid at the same level along the column height. Methacrylic acid are shown in table 2 composition taken in continuous mode through the side outlet for pure methacrylic acid.

Example 3

The experience carried out in accordance with example 1, adding bicarbonate aminoguanidine (1000 ppm) to the phlegm of the distillation column. Methacrylic acid are shown in table 2 composition taken in continuous mode from the head of the column.

Example 4

The experience carried out in accordance with example 1, while before distillation column set the supply tank for crude methacrylic acid and in that the supply tank add bicarbonate aminoguanidine (1000 ppm), the processing which is carried out at 50°C With residence time in the supply tank 1 hour. The mixture from the feed tank, then served in the distillation column and distilled by analogy with the previous one. Methacrylic acid are shown in table 2 composition taken in continuous mode through the side of the output columns.

An example of comparison of 4A

The experience carried out in accordance with example 4, but Methacrylic acid are selected not by the side of the conclusion, and in the head h and columns.

The furfural
Table 2
Example 1Example 1AExample 2Example 3Example 4Example 4A
Methacrylic acid99.91 per wt.%efficiency of 99.78 wt.%99.95 wt.%99,93 wt.%99.95 wt.%99,88 wt.%
Water80 ppm350 ppm60 ppm290 ppm70 ppm300 ppm
Propionic acid35 ppm150 ppm30 ppm170 ppm40 ppm180 ppm
Acrylic acid105 ppm450 ppm90 ppm520 ppm100 ppm520 ppm
<5 ppm8 ppm<5 ppm<5 ppm<5 ppm<5 ppm
Benzaldehyde<5 ppm<5 ppm<5 ppm<5 ppm<5 ppm<5 ppm
Carbonyl compounds in the amount of<10 ppm<10 ppm<10 ppm<10 ppm<10 ppm<10 ppm
Storable<10 ppm<10 ppm<10 ppm<10 ppm<10 ppm<10 ppm
Non-volatile compounds------
ARNA (Pt-Co)48<3 3<34
ppm - millionths

Example 5. Getting hydroxyamino pure methacrylic acid

In accordance with methods described in U.S. patent No. 3875211, in an atmosphere of nitrogen load in the autoclave to 60 parts by mass of methacrylic acid, 0.16 parts of the mass nanometrology ether of hydroquinone and 0.24 part of the mass of salicylate chromium. Add in the gas phase 36 parts of weight of ethylene oxide. The contents of the autoclave for three hours, heated at 80°C. ethylene oxide is removed in vacuum and the reaction mixture cooled down to room temperature. Then the reaction mixture was distilled in vacuum at 60°C and receive a solution with a high content of 2-hydroxyethylmethacrylate, a typical composition of which is given in table 3. There is a clear correlation between the purity of the applied methacrylic acid and the optical properties of the hydroxyether and content diapir. It plays an important role in the further processing of the hydroxyether, for example, in the case of polymerization for obtaining such products for biomedical application as soft permeable to oxygen contact lenses.

Table 3
(M IS K - methacrylic acid)
The POPPY PrimeroPOPPY in example 1AThe POPPY example 2POPPY in example 3MACS for example 4POPPY in example 4A
2-Hydroxyethyl-methacrylate98.2 wt.%97,2 wt.%98.9 wt.%98.4 wt.%98.5 wt.%is 97.9 wt.%
Fluids (for formation of the mesh)0.6 wt.%0.8 wt.%0.3 wt.%0.4 wt.%0.5 wt.%0.6 wt.%
ARNA (Pt-Co)5123435

Digital signs

1 Material flow

2 the First reaction tube

3 Second reaction tube

4 Salt bath

5 Gaseous crude methacrylic acid

6 Module rapid cooling

7 Water crude methacrylic who Isleta

8 low-boiling compounds

9 Distillation column for low-boiling compounds

10 low-boiling compounds

11 Water crude methacrylic acid

12 Module extraction

13 Organic phase crude methacrylic acid (extract)

14 Distillation column (cleaning unit)

15 low-boiling compounds

16 Containing methacrylic acid crude product

17 Distillation column with a dividing wall

18 Enter for containing methacrylic acid crude product

19 Inhibitor/stabilizer

20 Pure methacrylic acid

21 Head fraction of methacrylic acid

22 Cube fraction of methacrylic acid

23 Side conclusion for pure methacrylic acid

24 Inert area

25 the First oxidation catalyst

26 Inert area

27 Inert area

28 the Second oxidation catalyst

29 Inert area

30 Recycling of substances used for rapid cooling

31 Dividing wall

32 Distillation column without a separating wall

33 Input for containing methacrylic acid crude product

34 Side output

35 cleaning Module

36 Reflux

37 Module oxidation in the gas phase

38 Conclusion from Cuba

39 partitioner

40 Module crystallization

41 module

42 the Melter

43 Wall rect Picatinny columns

D the Main direction of flow containing methacrylic acid crude product

1. The method of obtaining pure methacrylic acid, including at least a stage of the method:
a) oxidation in the gas phase With4connection with the receipt containing methacrylic acid in the gas phase,
b) condensation containing methacrylic acid in the gas phase to obtain an aqueous solution of methacrylic acid,
C) allocating at least part of the methacrylic acid from the aqueous methacrylic acid with obtaining at least one containing methacrylic acid crude product,
d) allocating at least part of the methacrylic acid from at least one containing methacrylic acid crude product by means of thermal separation to obtain pure methacrylic acid,
moreover, at the stage of the process g) methacrylic acid is separated from at least part of at least one containing methacrylic acid crude product by distillation, and
and pure methacrylic acid are selected through the side output used for rectification column, and
the number of pure methacrylic acid taken in a certain time interval, ranging from 40 to 80% of the number containing methacrylic acid crude product supplied in rectificatio the percent column in the same time interval.

2. The method according to claim 1, where the phase of the process includes the following stages of the process:
1α) extraction of methacrylic acid from the aqueous methacrylic acid with an organic extractant to obtain the aqueous phase and organic phase,
1β) separating at least part of the organic solvent from the organic phase using at least one process of thermal separation of obtaining at least one containing methacrylic acid cubic product as containing methacrylic acid crude product.

3. The method according to claim 2, characterized in that the organic extractant, which is used at the stage of the process 1α), has a boiling point below 161°C, in particular at atmospheric pressure.

4. The method according to claim 1, where the phase of the process includes the following stages of the process:
2α) crystallizing at least part of the methacrylic acid from the aqueous methacrylic acid,
2β), if necessary, rinsing crystallized methacrylic acid,
2γ) melting at least part of the crystalline methacrylic acid to produce at least one product containing crude methacrylic acid.

5. The method according to claim 1, characterized in that applied to process stage d) at least one containing methacrylic acid crude productproduct in the distillation or crystallization of the composition, including most 95 wt.%, preferably a maximum of 90 wt.%, even more preferably a maximum of 85 wt.% methacrylic acid.

6. The method according to claim 1, characterized in that applied to process stage d) at least one containing methacrylic acid crude product is obtained in the distillation or crystallization composition comprising at least 5 wt.%, preferably at least 10 wt.%, even more preferably at least 15 wt.% hydrocarbons with carbon atoms from four to eight.

7. The method according to claim 1, characterized in that applied to process stage d) at least one containing methacrylic acid crude product has a score of ARNA in accordance with DIN ISO 6271 equal to at least 100, preferably equal to at least 250, even more preferably equal to at least 500.

8. The method according to claim 1, characterized in that the rectification stage of the process d) is performed at a pressure in the cube in the range from 1 to 100 mbar.

9. The method according to claim 1, characterized in that the rectification stage of the process d) is carried out at a temperature in Cuba in the range from 40 to 200°C.

10. The method according to claim 1, characterized in that the rectification stage of the process d) is carried out at a temperature in the cube less than 90°C.

11. The method according to claim 1, characterized in that the distillation column is from more than 0 to 10 theorem is practical plates per meter, preferably from 0.5 to 8 theoretical plates per meter, more preferably from 1 to 7 theoretical plates per meter and even more preferably from 1.5 to 6 theoretical plates per meter.

12. The method according to claim 1, characterized in that the stage of the process g) of pure methacrylic acid are selected based on the height in the area between the bottom quarter top quarter of the distillation column.

13. The method according to claim 1, characterized in that the flow of at least one containing methacrylic acid crude product supplied to the process stage d), meets the hydrodynamic resistance at entry or after entry into the distillation column.

14. The method according to item 13, wherein the stream entering the column at least one containing methacrylic acid crude product is sprayed in the hydrodynamic resistance at an angle in the range from 60 to 120° with respect to the main direction of flow in the column and greeters hydrodynamic resistance containing methacrylic acid crude product.

15. The method according to claim 1, characterized in that the at least one obtained in process stage b) containing methacrylic acid crude product is served to the cube of the distillation column.

16. The method according to claim 1, characterized in that at least one of the received n the stage of the process) containing methacrylic acid crude product is fed into the distillation column at the level of from 1 to 5 theoretical plates below the side of the output.

17. The method according to claim 1, where thermal separation process stage d) is carried out in the presence of decolorizing reagent.

18. The method according to 17, where decolorizing reagent is a salt aminoguanidine.

19. The method according to p, where the salt aminoguanidine bicarbonate is aminoguanidine.

20. The method according to 17, where decolorizing reagent is added
(A) at least one obtained in process stage b) containing methacrylic acid in the crude product before thermal separation stage of the process g) or
B) during thermal separation stage of the process g).

21. The method according to claim 1, where the process stage g) of the at least one containing methacrylic acid crude product obtained in process stage b), precipitated less than 5 wt.%, preferably less than 1.5 wt.% impurities, particularly preferably not precipitated impurities other than methacrylic acid.

22. The method according to one of claims 1 to 21, where the continuous scheme implemented at least in process stage d).

23. Device for producing methacrylic acid by the method according to any one of claims 1 to 22, which comprises at least listed further components associated with providing flow through them fluid:
a1) module oxidation in the gas phase,
B1) absorption module,
B1) the separation module, and
G1) module clear and,
when the cleaning module includes at least one distillation column, with at least one distillation column includes at least one lateral outlet for pure methacrylic acid.

24. Installation according to item 23, where the separation module includes
VA) module extraction and
WA) at least one primary distillation column, with at least one primary distillation column equipped with at least one placed at the bottom of the output associated with at least one distillation column to provide flow through them in a fluid medium.

25. Installation according to paragraph 24, where the separation module includes
VB) module crystallization and
VV) if necessary wash module.

26. Installation according to item 23, wherein the at least one distillation column is a distillation column.

27. Installation p where distillation column includes at least one side input for at least one containing methacrylic acid crude product.

28. Installation p, characterized in that the distillation column is a column with a dividing wall.

29. Application installation on one of PP-28 to implement the method according to one of claims 1 to 22.

30. The method of producing esters of methacrylate is howling acid, including stage of the process
A) obtaining pure methacrylic acid by the method according to one of claims 1 to 22, and
B) esterification of pure methacrylic acid.

31. The method of producing polymethacrylate, including stage of the process
i) obtaining pure methacrylic acid by the method according to one of claims 1 to 22, and
ii) radical polymerization of pure methacrylic acid, if necessary in the presence of monomers capable of copolymerization with methacrylic acid.

32. The method of producing esters of polymethacrylic acid, including stage of the process
i) produce methacrylic acid by the method according to item 30, and
ii) radical polymerization of methacrylic acid, if necessary in the presence of monomers capable of copolymerization with esters of methacrylic acid.



 

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EFFECT: expanded flocculation possibilities and reduced sensitivity to composition of fluids to be treated.

14 cl, 4 ex

The invention relates to new methods and materials to minimize deposition of metal oxides on the tubes of the steam generator to the secondary line pressure of steam generators in nuclear power plants (NPP) using a polymeric dispersant high purity

FIELD: chemistry.

SUBSTANCE: invention relates to synthesis of water-soluble trimetallic salts of acrylic and methacrylic acid copolymers. The method of producing water-soluble trimetallic salts of acrylic and methacrylic acid copolymers involves polymerisation of a mixture of acrylic and methacrylic acid in the presence of potassium persulphate with subsequent addition of a mixture of aqueous solutions of chlorides or sulphates of di- or trivalent metals in amount of 6.802-35.2776 moles and neutralisation of the remaining free acid with aqueous sodium hydroxide solution.

EFFECT: obtaining water-soluble salts of copolymers of different composition.

1 cl, 20 ex

FIELD: chemistry.

SUBSTANCE: content of acrylic aid or methacrylic acid in the liquid per total weight of liquid II is at least 10 wt %, where, along with methacrylic acid and/or acrylic acid, said liquid also contains acrolien and/or methacrolein, as well as acetone in total amount of not more than 5 wt % per total content of acrylic acid and/or methacrylic acid in liquid II, provided that liquid II was produced without adding acrolen or methacrolein in form of a pure substance of another liquid I containing acrylic acid and/or methacrylic acid, wherein liquid II, in which the weight ratio of acrolien to acetone contained therein is not equal to 3.5, liquid II is fed into the fractionation column provided that it contains at least 10 wt % acetone which inhibits polymerisation of acrylic and/or methacrylic acid, in terms of acrolein and methacrolein contained in liquid II.

EFFECT: less susceptibility of acrylic acid or methacrylic acid to polymerisation during fractional separation of liquid II.

8 cl, 3 tbl, 3 ex

FIELD: medicine.

SUBSTANCE: described is incomplete sodium salt of polyacrylic acid characterised by the fact that it corresponds to formula

.

Also described is method of obtaining said incomplete sodium salt of polyacrylic acid, characterised by the fact that to water solution of polyacrylic acid added is water solution of sodium acetate, reaction mixture is mixed for 10-15 minutes, obtained water solution is passed through cationite and dried in vacuum at temperature not higher than 50 degrees. Described is medication, possessing hemostatic action if applied externally, containing said salt of incomplete sodium salt of polyacrylic acid, characterised by the fact that it made in form of solution with ratio from 1- 10 g of basic substance per 100 ml of water.

EFFECT: obtaining novel chemical compounds, which can be applied in chemistry and medicine as hemostatic medication.

3 cl, 5 ex

FIELD: medicine, pharmaceutics.

SUBSTANCE: claimed invention relates to creation of novel chemical compounds, which can be used in chemistry and medicine as hemostatic medications. Described is incomplete potassium salt of polyacrylic acid, characterised by correspondence to formula . Also described is method of obtaining said incomplete potassium salt of polyacrylic acid, which is characterised by the following: water solution of potassium acetate is added to solution of polyacrylic acid, reaction mixture is mixed 10-15 more minutes, obtained water solution is dried in vacuum at temperature not higher than 50°C. Described is medication, which contains said incomplete potassium salt of polyacrylic acid, characterised by the fact that is made in form of solution with ratio 1-10 g of main substance per 100 ml of water, it possesses hemostatic action in external application.

EFFECT: obtaining novel chemical compounbds which can be used in chemistry and medicine as hemostatic medications.

3 cl, 5 ex

FIELD: medicine, pharmaceutics.

SUBSTANCE: claimed invention relates to creation of novel chemical compounds, which can be used in medicine as hemostatic medications of local action. Described is incomplete rubidium salt of polyacrylic acid, which is characterised by corresponding to formula:

. Also described is method of obtaining said above incomplete rubidium salt of polyacrylic acid, characterised by the following: to water solution of polyacrylic acid added is water solution of rubidium chloride, reaction mixture is mixed for 30-40 more minutes, obtained water solution is passed through cationite and dried in vacuum at temperature not higher than 50°C. Described is medication, containing said above incomplete rubidium salt of polyacrylic acid characterised by the following: it is made in form of solution with ratio 1-10 g of principal substance per 100 ml of water, possessing hemostatic action in external application.

EFFECT: obtaining novel chemical compounds which can be used in medicine as hemostatic medications.

3 cl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention relates to polymer materials which are sensitive to UV radiation, which can be used to make UV induced structures in laser devices. Described is a single-step method of producing transparent block polymer material which is sensitive to UV radiation owing to presence of a uniformly distributed gold compound therein. The method involves preparation of an initial reaction mixture by dissolving a radical polymerisation initiator, selected from organic peroxides, and a noble metal compound, selected from salts with anions AuCl4-, AuBr4-, AuF4-, Au(SCN)4- and cations of quaternary ammonium bases, for example, N-cetylpyridinium, in an acrylic monomer at room temperature in liquid state. Synthesis of the polymer takes place via radical polymerisation in the mass of degassed reaction mixture while heating to temperature higher than 25°C, but lower than the boiling point of the monomer and then holding the mixture at the given temperature for 3-30 hours.

EFFECT: simplified method enables to obtain block materials which are sensitive to UV radiation.

5 cl, 2 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of producing (meth)acrylates of N-hydroxy-alkylated amides, in which cyclic N-hydroxyalkylated amides (C): , where Z1 denotes unsubstituted or mono-substituted nitrogen (N-R3); R1 and R2, in each case independently denote an alkylene with 2-20 carbon atoms, cycloalkylene with 5-12 carbon atoms, arydene with 6-12 carbon atoms; R3 denotes hydrogen, alkyl with 1-18 carbon atoms, alkenyl with 2-18 carbon atoms, aryl with 6-12 carbon atoms or cycloalkyl with 5-12 carbon atoms; etherified with methacrylic acid or reesterified with at least one (meth)acrylic ester (D) in the presence of at least one heterogeneous catalyst selected from a group consisting of inorganic salts (Co), having pKb not higher than 7.0 and not lower than 1.0, and its solubility in the reaction medium at 25°C is not more than 1 g/l, and enzymes (F) selected from a group comprising esterase (E.C.3.1.-.-), lipase (E.C.3.1.1.3), glycosylase (E.C.3.2. -.-) and protease (E.C.3.4. -.-), where the heterogeneous catalyst is separated from the reaction mixture through filtration, electrofiltration, absorption, centrifuging or decantation.

EFFECT: efficient method of producing (meth)acrylates of N-hydroxyalkylated amides.

6 cl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention describes a polymer matrix for controlled release of medicinal agents for local transdermal administration, where the said matrix contains copolymers of acrylic or methacrylic acid and their esters, having Tg lower than 0°C, where free carboxyl groups form salts stoichiometric amounts of compatible organic bases. Described also is a method of preparing said matrices, which involves treatment of a copolymer having Tg lower than 0°C and free carboxyl groups suspended in an organic solvent with an aqueous solution of organic bases in stoichiometric amounts relative the carboxyl groups, and then addition of an active component and any other auxiliary substances.

EFFECT: disclosed matrices improve solubility, stability and diffusion of the agent from the matrix.

9 cl, 5 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention enables high-output production of a water-absorbing resin having an improved relationship between absorption capacity and water-soluble polymer. The polymerisation reaction is easier to control taking into account that the said properties of the water-absorbing resin are inversely related. The method of producing a water-absorbing resin through polymerisation of a composition based on acrylic acid, including acrylic acid and its salt, involves (a) a stage where radical polymerisation takes place with formation of a hydrogel of a cross-linked polymer and a stage (b) for drying the hydrogel of the cross-linked polymer while heating. Content of non-polymerised organic compound in the composition based on acrylic acid ranges from 1 to 1000 pts. wt, and the non-polymerised organic compound has solubility parametre of (1.0-2.5)×104 (J·m3)1/2. The obtained water-absorbing resin has final content of non-polymerised organic compound ranging from 0.01 to 10 pts. wt and final content of iron ranging from 0.01 to 1 pts. wt. The invention also pertains to a water-absorbing resin obtained through polymerisation of the composition based on acrylic acid, a sanitary product, a composition based on acrylic resin for producing the water-absorbing resin and a method of preparing the composition based on acrylic acid.

EFFECT: obtained resin does not have a smell, is colourless and has good absorption properties.

16 cl, 1 tbl, 35 ex

FIELD: medicine.

SUBSTANCE: there is described invert-emulsion polymer, differing that it includes: a disperse phase containing an aqueous solution of acrylic polymer; a dispersive phase consisting of fatty acid ester and water-soluble C1-C4 alcohol; oil-soluble/ water-insoluble surface-active substance; an emulsifier with low HLB within 1.5 to 7.5 and an emulsifier with high HLB within 9 to 16 where invert-emulsion polymer has the reduced specific viscosity (RSV) at least 10 dl/g. There is also described method of water treatment that involves: addition of said invert-emulsion polymer to an industrial water system and hydrolysis of oil to fatty acid within said industrial water system. There is described method for making said invert-emulsion polymer.

EFFECT: production of safe and effective invert-emulsion polymer to be applied to the water systems and liquids at high temperature and pressure.

19 cl, 1 ex

FIELD: machine building.

SUBSTANCE: invention refers to a method for obtaining an ether additive, which involves mixing of dicarboxylic acid with ether so that water, ether and excess alcohol is obtained with further separation of water and alcohol from ether by rectification; at that, as an acid there used is oxalic acid, and as alcohol - n-butanol or 2-ethylhexanol. Cyclohexane used as a solvent is supplied for mixing of oxalic acid with alcohol, and rectification is performed in two columns so that cyclohexane (solvent) is obtained in the first column, which is returned to the stage of mixing with oxalic acid and alcohol and supply of residue of the first column to the second one so that alcohol and target product (ether additive) are obtained in it.

EFFECT: method allows simplifying the process and making it more economic by excluding the use of a catalyser, processing stages of reaction mass with an agent decomposing the catalyser, and reaction mass sorption and filtration stages.

2 cl, 2 dwg, 1 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to chemical engineering and specifically to processing fusel oil, which is a large-tonnage waste in the alcohol industry. Fusel oil from production of ethyl alcohol is processed by esterification with glacial acetic acid in the presence of a sulphuric acid catalyst, and neutralisation, wherein esterification is carried out while boiling the reaction mixture and continuously separating water using a separating flask. The obtained product is separated from the catalyst under a vacuum at temperature not higher than 110°C. The obtained product and the catalyst are separately neutralised and the obtained product is additionally dried.

EFFECT: method enables to process fusel oil into a highly efficient component of mixed solvents of high quality with low cost of production and high output of the product.

4 cl

FIELD: chemistry.

SUBSTANCE: invention relates to novel dimethacrylic esters of dimerised fatty acid used as binding materials when producing various composite materials, in filling compounds and anaerobic sealants. Dimethacrylic esters of dimerised fatty acid have the structural formula: in which R=CH2CH2OCH2CH2; СН2СН2ОСН2СН2ОСН2СН2; (СН2)4; СН2СН2;

EFFECT: improved method.

2 tbl, 7 ex

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