Method of separating multi-atom alcohols, neopentylglycol and sodium formiate

FIELD: chemistry.

SUBSTANCE: method of separating multi-atom alcohols, for instance, neopentylglycol and sodium formiate, includes evaporation and cooling of reaction mixture, addition of organic solvent, crystallisation of sodium formiate, separation of sodium formiate from saturated solution of multi-atom alcohol, for instance, by filtration, and crystallisation of multi-atom alcohol. Reaction mixture is evaporated until two liquid layers are formed, which are separated into light phase - water-multi-atom alcohol and heavy phase -water-salt, separated water-salt fraction of solution is cooled until sodium formiate contained in it in form of cryslallohydrate is crystallised, sodium formiate crystals are separated, and remaining mother-solution is returned to process head, to evaporation stage, then separated light phase - water-multi-atom alcohol is additionally evaporated until 70% of contained in it sodium formiate is crystallised, then cooled to 25-30°C and subjected to processing with organic solvent from line of single-atom saturated alcohols, for instance, methane, for removal of remaining admixtures, with further crystallisation of multi-atom alcohol from remaining mother-solution.

EFFECT: reduction of amount of used organic solvent, elimination of high-temperature stage of extraction, preservation of yield of pure target products.

2 cl, 2 dwg, 1 ex

 

The invention relates to the field of chemistry, in particular to a method of separation of polyols, such as neopentyl glycol, and sodium formate.

Polyhydric alcohols: 1,1,1-trimethylated (Merial), 1,1,1-trimethylolpropane (atrial), 2,2-DIMETHYLPROPANE (neopentylglycol) and others - find wide industrial application in the production of high quality synthetic oils, alkyd and epoxy resins, varnishes, plastics, plasticizers, surfactants and other valuable products.

Synthesis of neopentyl glycol flows through the aldol condensation samalanga aldehyde with formaldehyde. The process is quite fast and does not require complex technological design. The main problem in the synthesis is the selection of neopentyl glycol from the reaction mixture. In industry there are several ways of extracting neopentyl glycol products from synthesis: remove sodium formate ion-exchange resins; sublimation neopentyl glycol; azeotropic distillation of the water of aliphatic, cycloaliphatic or aromatic hydrocarbons with subsequent extraction of neopentyl glycol water from anhydrous syrup; extraction of neopentyl glycol solvent countercurrent column. Each method has its advantages and disadvantages (see Rudkovskaya D.M., Keziah MM, Appel F.A. Mnogovato the haunted spirits. L.: Chemistry, 1972, s-138).

The known method of separation of polyols, such as neopentyl glycol or atrial, and sodium formate or calcium, comprising adding to the mixture of the partial organic solvent, in which the polyhydric alcohol is dissolved, the crystallization of sodium formate or calcium, Department of formate sodium or calcium from the solution of a polyhydric alcohol in an organic solvent, for example, by filtration, recycling of organic solvent, cooling the solution and crystallization of a polyhydric alcohol, and as the organic solvent used solvent aromatic series such as toluene, in this case after adding to the mixture of the partial substances organic solvent, the resulting mixture is heated to boiling point and produce at this temperature at the same time: dehydration of the mixture by distillation with water recirculation separated from water, organic solvent, crystallization dissolved in an organic solvent, sodium formate or calcium and dissolution in an organic solvent, a polyhydric alcohol. The method allows to increase the output well of purified target product (see U.S. Pat. Of the Russian Federation No. 2230729, publ. 20.06.2004, IPC SS 31/20). This method is used as a prototype for the proposed technical solutions.

The disadvantages of the method protot the PA is a multi-stage process, the use of a large amount of solvent and heating it to high temperatures.

The objective of the invention is to develop a method of separation of polyols, such as neopentyl glycol, and sodium formate in one cycle, reducing the amount of organic solvent, the exclusion of high-temperature phase extraction while maintaining the yield of pure target product.

The technical result is to simplify the process, holding it in softer terms.

The problem is solved using the characteristics listed in the 1st paragraph of the claims, in common with the prototype, such as the method of separation of polyols, such as neopentyl glycol, and sodium formate using an organic solvent, crystallization of substances and separating them from the solution, and distinctive, essential features, such as, the reaction mixture is evaporated to the formation of two liquid layers, which are separated into a light phase is water-polyhydric alcohol and a heavy phase - salt-water, the separated water-salt part of the solution is cooled until crystallization contained sodium formate in the form of crystalline, separated crystals of sodium formiate, and the remaining solution of the mother liquor returned to the head of process at the stage of evaporation, and then the separated light phase water-polyhydric the Peart additionally evaporated until crystallization 70% of the contained sodium formate, then cooled to 25-30°and treated with an organic solvent from a number of monatomic limit alcohols, such as methanol, to remove the remaining impurities deposited precipitate was separated from the solution, for example by filtration, and the remaining mother liquor is crystallized polyhydric alcohol.

According to paragraph 2 of the claims crystallization of a polyhydric alcohol, such as neopentyl glycol, produced by the process of evaporation (removing) the remaining aqueous solution monatomic limit alcohol, for example methanol.

The above set of features of both known and new ones can carry out the process of separating substances described in paragraphs 1-2 of the claims, to obtain the shared substance sufficiently high degree of purity in one cycle, to reduce the use of organic solvent, to exclude high-temperature phase extraction while maintaining the yield of pure target product.

The above distinguishing features of each separately and all together aimed at solving the problem and are significant. The use of the proposed combination of essential distinctive features in the prior art was not found, therefore the proposed solution meets the criterion of patents is osobnosti "novelty".

One set of new essential features of a General known provides a solution to the problem is not obvious to a person skilled in the art and demonstrates compliance of the claimed technical solution (for the method) the patentability criterion of "inventive step".

To determine the temperature and concentration conditions of the process of fractional crystallization of neopentyl glycol and sodium formate was studied solubility in multicomponent aqueous-organic systems containing neopentylglycol, sodium formate, methanol and water (1, 2).

Below is an example embodiment of the invention.

Example.

Carry out the synthesis of a polyhydric alcohol is neopentyl glycol in a known manner, by reacting samalanga aldehyde with formaldehyde in the presence of sodium hydroxide, followed by neutralization of the reaction mixture with formic acid. Received sintasath evaporated by two-thirds of the volume to split the solution into two layers and is divided into two parts: a light phase and water-glycol and heavy phase - water-salt and processed further separately for each part.

Processing water-glycol part. Water-glycol part one stripped off of Sintashta containing 79,4% neopentyl glycol, 5.4% of sodium formate, 3,0% impurities (C12...) and 12.2% of water, after the separation layer is optionally evaporated until crystallization 70% of the contained sodium formate (1, 2). Next, for every 100 mass parts one stripped off and cooled to 30°With water-glycol side take to 1.7 mass parts of methanol, separating crystalline sodium formate from a solution of neopentyl glycol in an aqueous solution of methanol, for example, by filtration at a temperature of about 30°C.

From the aqueous-methanolic solution of neopentyl glycol to produce crystallization of neopentyl glycol by evaporation (removing) the remaining aqueous solution of methanol.

The result for each 100 wt. parts of the mixture obtained by the process of evaporation of Sintashta, 63,2 wt. parts of neopentyl glycol containing not more than 0.3% of sodium, the product yield 69.3% 4,39 wt. part of the sodium formate content of the basic substance is not less than 99.2%.

Processing of water-salt part. Water-salt part one stripped off of Sintashta after separation of the layers cooled to 0°to crystallization of hydrated sodium formate and separate the salt crystals, for example, by filtration. The remaining solution of the mother liquor returned to the head of process at the stage of parki.

The result for each 100 mass parts of the taken solution 63,64 parts of sodium formate or calcium content of the basic substance 99,0, output operations 77,59%. Formed during exhaust solution of methanol used again in the process operation of water-glycol part one stripped off the synth is the ZAT (see above).

From the description and practical application of the present invention to specialists will be obvious and other private forms of its implementation. The description and examples are considered to illustrate the invention, the essence of which and the scope of patent claims is defined in the following claims, a set of essential features and their equivalents.

1. The method of separation of polyols, such as neopentyl glycol, and sodium formiate, including evaporation and cooling of the reaction mixture, adding an organic solvent, crystallization of sodium formiate, the separation of sodium formiate from a saturated solution of a polyhydric alcohol, for example, by filtration and crystallization of a polyhydric alcohol, wherein the reaction mixture is evaporated to the formation of two liquid layers, which are separated into a light phase is water - polyhydric alcohol and a heavy phase - salt-water, the separated water-salt part of the solution is cooled until crystallization contained sodium formate in the form of crystalline, separated crystals of sodium formiate, and the remaining a solution of the mother liquor returned to the head of process at the stage of evaporation, and then the separated light phase - water - polyhydric alcohol additionally evaporated until crystallization 70% contained formate intothree is, then cooled to 25-30°and treated with an organic solvent from a number of monatomic limit alcohols, such as methanol, to remove the remaining impurities deposited precipitate was separated from the solution, e.g. by filtration, and the remaining mother liquor is crystallized polyhydric alcohol.

2. The method according to claim 1, characterized in that the crystallization of a polyhydric alcohol, such as neopentyl glycol, produced by the process of evaporation (removing) the remaining aqueous solution monatomic limit alcohol, for example methanol.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: preparation of liquid flow I, containing formic acid, and liquid flow II, containing alkali metal formate, is carried out; liquid flows I and II are supplied to rectification column in such way that for liquid flow II place for feeding into rectifying column is chosen higher than place of feeding liquid flow I, or the same place as for liquid flow I, liquid flows I and II are mixed in rectification column, removing water from upper part of rectification column, and lower flow, containing formic acid formate is removed from rectification column, lower flow being separated in form of melt, which contains less than 0.5 wt % of water.

EFFECT: improved method of production of formic acid formates.

10 cl, 4 ex

FIELD: chemical industry; methods of production of the manganese salts with the organic acids.

SUBSTANCE: the invention is pertaining to production of the manganese salts with the organic acids in particular, to the salt of the divalent manganese and formic acid. The method is exercised by interaction of manganese, its oxides in the state of the highest valence with the formic acid solution in the organic solvent in the presence of iodine as the stimulating additive. The production process is conducted in the bead grinder of the vertical type having the revertive cooler-condenser, the high-speed paddle stirrer and the glass beads of in the capacity of the grinding agent loaded in the mass ratio to the loading of the liquid phase as (1÷2): 1. The liquid phase consists of the formic acid solution in the organic solvent. The concentration of the acid is taken within the range of 3.5÷10.8 mole/kg. In the loaded liquid phase they dissolve the stimulating additive of iodine in the amount of 0.025-0.100 mole/kg of the liquid phase. The ratio of the masses of the liquid phase and the total of the metallic manganese and the manganese oxide are as(4.9÷11):1. The molar ratio of the metal and the oxide in the loading is as (1.8÷2.,2):1. The metal and the oxide are loaded the last. It is preferable in the capacity of the dissolvent to use the butyl alcohol, ethyl acetate, ethylene glycol, 1.4-dioxane, dimethyl formamide. The production process is started and conducted at the indoor temperature up to practically complete(consumption of the whole loaded manganese oxide. Then the stirring is stopped, the suspension of the salt is separated from the beads and the nonreacted manganese and after that conduct filtration. The filtrate and the nonreacted manganese are returned into the repeated production process, and the filtered out settling of the manganese salt is exposed to purification by recrystallization. The technical result of the invention is - simplification of the method at usage of accessible reactants.

EFFECT: the invention ensures simplification of the method at usage of accessible reactants.

16 ex, 2 tbl

FIELD: concentration of pentaerythrite formate mother liquors in the multi-case evaporation plant with vertical heat exchange tubes for production of high-quality lacquers, additives for oils and other products.

SUBSTANCE: proposed method includes concentration of pentaerythrite formate mother liquors at the first stage by evaporation to saturation state by pentaerythrite and crystallization of pentaerythrite from saturated solution; concentration at the first stage is performed at film flow solution; crystallization is carried out at two stages at forced circulation of suspension thus formed. Secondary vapor is divided into two flows after first stage of evaporation: one flow is delivered to the first stage of crystallization and second flow is delivered to the second stage of crystallization. At the second stage of crystallization boiling point of suspension is maintained at temperature of 45-53°C which is below that at the first stage by 7-20°C. Evaporation plant for processing the pentaerythrite formate mother liquors has two stages of evaporators connected in succession in way of flow of vapor and solution and provided with vertical tubes. Second stage of evaporation plant is just crystallizer provided with circulating loop with pump and vapor separator connected with final condenser by means of vapor pipe line. First stage consists of film liquid flow evaporator; second stage is provided with additional crystallizer with circulating loop and pump and additional condenser connected with vapor separator of additional crystallizer; it is also provided with non-condensable gas discharge unit. Last evaporator of the first stage is provided with additional pipe line for discharge of secondary vapor which is communicated with heating chamber of additional crystallizer. Solution volume of additional crystallizer exceeds that of the first one by 1.5- 2.5 times.

EFFECT: improved quality of crystalline products; increased degree of extraction of pentaerythrite from solution; increased rate of processing the solutions.

6 cl, 1 dwg, 1 tbl

FIELD: inorganic synthesis.

SUBSTANCE: invention relates to preparation of salts of transition metals with organic acids, in particular to formic acid ferric salt. Method is accomplished via oxidation of ferrous formate with hydrogen peroxide in presence of formic acid and in absence of any dorm of iron as reducer in order to prevent reduction of ferric salt into original ferrous salt. As reducer, ferrous formate is used preliminarily recrystallized and dried or filtered off from reaction mixture suspension. Process is carried out in upright bead mill in two steps. In the first step, ferrous formate powder or precipitate is combined, stepwise or in one go, with 85% formic acid or mixture of filtrate with wash water formed during isolation of desired product to form pasty slurry ensuring stable functioning of bead mill. Second-step operation is effected in bead mill functioning mode involving forced cooling through side surfaces of reactor and continuous introduction of 12.5-25% hydrogen peroxide solution at a rate of 3.25-4.24 g H2O2 per 1 kg starting charge until degree of Fe(II) salt conversion achieves 85-90%. Supply velocity is then lowered until complete conversion is reached. Resulting product slurry is separated from beads and filtered. Filter cake is washed with 85% formic acid and recrystallized in saturated ferric formate solution containing 20-30% of formic acid. Wash liquid is combined with filtrate and used in the first step as described above.

EFFECT: increased yield of target product and simplified its isolation step.

1 tbl, 8 ex

FIELD: inorganic synthesis.

SUBSTANCE: invention relates to preparation of salts of transition metals with organic acids, in particular to formic acid ferric salt. Method is accomplished in bead mill provided with mechanical blade-type stirrer in aqueous formic acid solution (5-10 mole/kg). Iron is used in the form of steel sidewall across the height of reactor and also as particles of reduced iron stirred with stirrer together with glass beads, and/or as broken steel cuttings, and/or yet as split cast iron in any weight proportions. Method is accomplished by continuously introducing 10-20% hydrogen peroxide solution at a rate of 0.015-0,030 mole peroxide/min per 1 kg liquid phase (salt slurry) in presence of stimulating additive, in particular iodine, bromine, alkali metal or ferrous iodides or bromides in amounts (on conversion to halogens) 0.1-0.15 vole per 1 kg reaction mixture. When 1,2-1,5 mole/kg of ferrous salt is accumulated in reaction mixture, stirring and addition of hydrogen peroxide solution are stopped, product slurry is separated from unreacted iron and/or its alloys as well as from glass beads and filtered. Filtrate is recycled into process and precipitate is recrystallized from saturated iron formate solution of aqueous formic acid solution (1-2 mole/kg).

EFFECT: simplified finished product isolation stage, reduced total process time, and reduced power consumption.

1 tbl, 11 ex

FIELD: chemical industry; methods of production of the salts of iron and the organic acids.

SUBSTANCE: the invention is pertaining to the field of chemical industry, in particular, to the method of production of the salts of iron and the organic acids, in particular, to production of the salt of the ferrous iron and the formic acid. The method is realized by the direct interaction of the acid with the iron, its alloys and the ferric oxides. The crumber with the beads and the backflow condenser is loaded with the organic solvent, the formic acid and the water in the mass ratio of 100:(85÷100): (15÷0). As the organic solvent they use ethylcellosolve, butyl acetate, butyl and amyl alcohols, ethylene glycol. The mass ratio of the beads and the liquid phase is 1:1. Ferric oxideFe2O3 orFe3O4 and the iodine are loaded in the amount of 0.40-0.56 or 0/21-0.42 and 0.03-0.1 mole/kg of the liquid phase accordingly. The iron is introduced in the form of the steel shell along the whole height of the reactor and additionally in form of the reduced iron, the fractions of the broken cast iron with dimensions of up to 5 mm and the steel chips in any ratio among themselves at total amount of 20 % from the mass of the liquid phase. The process is conducted at the temperature of 35-55°С practically till the complete consumption of the ferric oxide. The gained suspension is separated from the beads and the metal particles of the greater dimensions and subjected to centrifuging or sedimentation. The clarified liquid phase is returned to the repeated process, and the solid phase is dissolved at stirring action and warming up to 85-95°С in the water solution of the formic acid saturated by the ferric formiate (II) up to 1-2 mole/kg. The present solid impurities are removed at the hot filtration process and the filtrate is cooled and the salt crystals are separated. The technical result of the invention is simplification of the technology of the production process with utilization of the accessible raw.

EFFECT: the invention ensures simplification of the technology of the production process with utilization of the accessible raw.

3 cl, 17 ex

FIELD: chemical industry; methods of production of the salts of iron and the organic acids.

SUBSTANCE: the invention is pertaining to the field of chemical industry, in particular, to the method of production of the salts of the metals of the organic acids, in particular, to production of the salt of the ferrous iron and the formic acid. The method is realized by the direct interaction of the formic acid water solution with the iron and/or its alloys and the ferric oxidesFe2O3 and Fe3O4 in the bead crumber of the vertical type along the whole its height with the steel shell, with the heat supply and equipped with the mechanical stirrer and the backflow condenser-refrigerator. The apparatus is loaded with 23-46 % water solution of the formic acid as the liquid phase in the mass ratio with the glass beads as 1:1.25 and then introduce the oxide - Fe3O4 orFe2O3 in amount of 0.27-0.49 or 0.48-0.64 mole/kg of the liquid phase accordingly, and besides in amount of 18 % from the mass of the liquid phase they add the powder of the reduced iron and-or the crushed cast iron, and-or the crushed steel chips in any mass ratios. Switch on the mechanical stirring and heating and keep the temperature in the reaction zone within the limits of 55-75°С. The process is terminated, when practically the whole loaded oxide is completely consumed. The suspension of the salt is separated from the non-reacted iron, its alloy and the beads and dilute with the water up to the contents of the formic acid within the limits of 1-2 mole/kg. The gained mass at stirring action is slowly heated up to temperature of 85-95°С, controlling transformation of the solid phase into the solution. The gained solution is subjected to the hot filtration, evaporation, cooling and separation of the salt crystals. The filtrate and the earlier the gained distillate are sent back to the repeated process. The technical result of the invention is simplification of the technology of the production process with utilization of the accessible raw.

EFFECT: the invention ensures simplification of the technology of the production process with utilization of the accessible raw.

10 ex

FIELD: production of salts of organic acids, salt of ferrous iron and formic acid in particular.

SUBSTANCE: proposed method consists in loading preliminarily prepared aqueous solution of formic acid at concentration of 4.5-10 mole/kg into reactor provided with bladed mixer, back-flow condenser-cooler and air bubbler. Then, powder of reduced iron and/or broken iron and/or steel chips at any mass ratio in total amount of 20.0-30.6% of mass of liquid phase and stimulating iodine additive in the amount of 0.016-0.164 mole/kg of liquid phase are introduced. Reactor may be provided with steel or cast iron ferrule over entire height. At mechanical mixing, consumption of air for bubbling is maintained between 1.2 and 2.0 l/(min·kg of liquid phase). Working temperature range is 45-65°C which is maintained by external cooling. Process is discontinued when content of iron salts (II) in reaction mixture reaches 1.8-2.0 mole/kg. Suspension of salt in liquid phase is separated from unreacted iron particles and is filtered afterwards. Filtrate is directed for repeated process and salt sediment is re-crystallized from aqueous solution saturated with iron formate by formic acid at concentration of 1-2 mole/kg at heating to temperature of 95°C followed by natural cooling.

EFFECT: enhanced efficiency.

1 tbl, 9 ex

FIELD: chemical industry; methods of production of the ferric formiate (III).

SUBSTANCE: the invention is pertaining to the field of chemical industry, in particular, to the method of production of the ferric formiate (III). The invention is dealt with the organic salts of the transition metals, in particular to production of the salt of the ferric iron and the formic acid. The method is realized by the direct interaction of the regenerated iron powder with the formic acid at presence of the molecular iodine and oxygen of the air as the oxidizing agents. The process is running in the medium of dimethylformamide as the dissolvent for preparation of the necessary liquid phase with the concentrations of the formic acid and iodine of 4.5-10 and 0.03-0.11 mole/kg accordingly. The mass ratio of the liquid phase and the powder of the regenerated iron is 3:1. The process starts at the room temperature and is conducted in the conditions of the forced cooling at the temperature of 50-80°С at the rate of the air consumption for the bubbling of 0.6-1.2 l\minute per 1 kg of the liquid phase. The process is terminated at accumulation of the ferric formiate (III) in the suspension up to 1-1.2 mole/kg. The suspension is separated from the particles of the non-reacted iron and then filtered. The filtrate is recycled to the repeated process, and the ferric formiate (III) (salt) is dried and either is used as required, or additionally is purified by the recrystallization. The technical result of the invention is simplification of the method with improvement of the economic indicators and the increased purity of the final product.

EFFECT: the invention ensures simplification of the method with improvement of the economic indicators and the increased purity of the final product.

8 ex

FIELD: anti-conglomeration agents.

SUBSTANCE: invention relates to loose product based on potassium formate, which contains 0.1 to 1% water and 0.5-5% water-soluble conglomeration-preventing agent, such as potassium carbonate or potassium hydroxide, which possesses affinity for water and corresponds to equilibrium humidity below equilibrium 15% relative humidity (22°C) for potassium formate.

EFFECT: provided modifying and conglomeration preventing agents for potassium formate to allow it to achieve looseness under practical storage and processing conditions.

3 cl, 4 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method, by which the carboxylic acid/diol mixture, that is suitable as the initial substance for the manufacture of polyester, obtained from the decolourised solution of carboxylic acid without actually isolating the solid dry carboxylic acid. More specifically, the invention relates to the method of manufacturing a mixture of carboxylic acid/diol, where the said method includes the addition of diol to the decolourised solution of carboxylic acid, which includes carboxylic acid and water, in the zone of the reactor etherification, where diol is located at a temperature sufficient for evaporating part of the water in order to become the basic suspending liquid with the formation of the specified carboxylic acid/diol mixture; where the said carboxylic acid and diol enter into a reaction in the zone of etherification with the formation of a flow of a complex hydroxyalkyl ether. The invention also relates to the following variants of the method: the method of manufacture of the carboxylic acid/diol mixture, where the said method includes the following stages: (a) mixing of the powder of damp carboxylic acid with water in the zone for mixing with the formation of the solution of damp carboxylic acid; where the said carboxylic acid is selected from the group, which includes terephthalic acid, isophthatic acid, naphthalenedicarboxylic acid and their mixtures; (b) discolourisation of aforesaid solution of damp carboxylic acid in the zone for reaction obtaining the decolourised solution of carboxylic acid; (c) not necessarily, instantaneous evaporation of the said decolourised solution of carboxylic acid in the zone of instantaneous evaporation for the removal of part of the water from the decolourised solution of carboxylic acid; and (d) addition of diol to the decolourised solution of carboxylic acid in the zone of the reactor of the etherification, where the said diol is located at a temperature, sufficient for the evaporation of part of the water in order to become the basic suspending liquid with the formation of the carboxylic acid/diol mixture; where the aforesaid carboxylic acid and diol then enter the zone of etherification with the formation of the flow of complex hydroxyalkyl ether; and relates to the method of manufacture of carboxylic acid/diol, where the said method includes the following stages: (a) the mixing of the powder of damp carboxylic acid with water in the zone for mixing with the formation of the solution of carboxylic acid; (b) discolourisation of the said solution of damp carboxylic acid in the reactor core with the formation of the decolourised solution of carboxylic acid; (c) crystallisation of the said decolourised solution of carboxylic acid in the zone of crystallisation with the formation of an aqueous suspension; and (d) removal of part of the contaminated water in the aforesaid aqueous solution and addition of diol into the zone of the removal of liquid with the obtaining of the said carboxylic acid/diol mixture, where diol is located at a temperature sufficient for evaporating part of the contaminated water from the said aqueous suspension in order to become the basic suspending liquid.

EFFECT: obtaining mixture of carboxylic acid/diol.

29 cl, 4 dwg

FIELD: chemistry.

SUBSTANCE: invention pertains to the perfection of the method of regulating quantities of dissolved iron in liquid streams during the process of obtaining aromatic carboxylic acids or in the process of cleaning technical aromatic carboxylic acids, characterised by that, to at least, part of the liquid stream for regulating the quantity of dissolved iron in it, at least one peroxide with formula R1-O-O-R2 is added. Here R1 and R2 can be the same or different. They represent hydrogen or a hydrocarbon group, in quantities sufficient for precipitation of the dissolved iron from the liquid. The invention also relates to the perfection of the method of obtaining an aromatic carboxylic acid, through the following stages: A) contacting the crude aromatic material which can be oxidised, with molecular oxygen in the presence of an oxidising catalyst, containing at least, one metal with atomic number from 21 to 82, and a solvent in the form of C2-C5 aliphatic carboxylic acid in a liquid phase reaction mixture in a reactor under conditions of oxidation with formation of a solid product. The product contains technical aromatic carboxylic acid, liquid, containing a solvent and water, and an off-gas, containing water vapour and vapour of the solvent; B) separation of the solid product, containing technical aromatic carboxylic acid from the liquid; C) distillation of at least part of the off gas in a distillation column, equipped with reflux, for separating vapour of the solvent from water vapour. A liquid then forms, containing the solvent, and in the upper distillation cut, containing water vapour; D) returning of at least, part of the liquid from stage B into the reactor; E) dissolution of at least, part of the separated solid product, containing technical aromatic carboxylic acid, in a solvent from the cleaning stage with obtaining of a liquid solution of the cleaning stage; F) contacting the solution from the cleaning stage with hydrogen in the presence of a hydrogenation catalyst and under hydrogenation conditions, sufficient for formation of a solution, containing cleaned aromatic carboxylic acid, and liquid, containing a cleaning solvent; G) separation of the cleaned aromatic carboxylic acid from the solution, containing the cleaning solvent, which is obtained from stage E, with obtaining of solid cleaned aromatic carboxylic acid and a stock solution from the cleaning stage; H) retuning of at least, part of the stock solution from the cleaning stage, to at least, one of the stages B and E; I) addition of at least, one peroxide with formula R1-O-O-R2, where R1 and R2 can be the same or different, and represent hydrogen or a hydrocarbon group, in a liquid from at least one of the other stages, or obtained as a result from at least one of these stages, to which the peroxide is added, in a quantity sufficient for precipitation of iron from the liquid.

EFFECT: controlled reduction of the formation of suspension of iron oxide during production of technical aromatic acid.

19 cl, 1 dwg, 6 ex, 4 tbl

FIELD: chemical industry; methods of production of the purified crystalline terephthalic acid.

SUBSTANCE: the invention is pertaining to the improved method of production and separation of the crystalline terephthalic acid containing less than 150 mass ppm of the p-toluene acid in terms of the mass of the terephthalic acid. The method provides for the following stages: (1) loading of (i) para- xylene, (ii) the water reactionary acetic-acidic medium containing the resolved in it components of the oxidation catalyst, and (iii) the gas containing oxygen fed under pressure in the first zone of oxidation, in which the liquid-phase exothermal oxidization of the para-xylene takes place, in which the temperature and the pressure inside the first being under pressure reactor of the oxidization are maintained at from 150°С up to 180°С and from 3.5 up to 13 absolute bars; (2) removal from the reactor upper part of the steam containing the evaporated reactionary acetic-acidic medium and the gas depleted by the oxygen including carbon dioxide, the inertial components and less than 9 volumetric percents of oxygen in terms of the non-condensable components of the steam; (3) removal from the lower part of the first reactor of the oxidized product including (i) the solid and dissolved terephthalic acid and (ii) the products of the non-complete oxidation and (ii) the water reactionary acetic-acidic medium containing the dissolved oxidation catalyst; (4) loading of (i) the oxidized product from the stage (3) and (ii) the gas containing oxygen, into the second being under pressure zone of the oxidation in which the liquid-phase exothermal oxidization of the products of the non-complete oxidization takes place; at that the temperature and the pressure in the second being under pressure reactor of the oxidization are maintained from 185°С up to 230°С and from 4.5 up to 18.3 absolute bar; (5) removal from the upper part of the second steam reactor containing the evaporated water reactionary acetic-acidic medium and gas depleted by the oxygen, including carbon dioxide, the inertial components and less, than 5 volumetric percents of oxygen in terms of the non-condensable components of the steam; (6) removal from the lower part of the second reactor of the second oxidized product including (i) the solid and dissolved terephthalic acid and the products of the non-complete oxidation and (ii) the water reactionary acetic-acidic medium containing the dissolved oxidation catalyst; (7) separation of the terephthalic acid from (ii) the water reactionary acetic-acidic medium of the stage (6) for production the terephthalic acid containing less than 900 mass ppm of 4- carboxybenzaldehyde and the p-toluene acid; (8) dissolution of the terephthalic acid gained at the stage (7) in the water for formation of the solution containing from 10 up to 35 mass % of the dissolved terephthalic acid containing less than 900 mass ppm of the 4- carboxybenzaldehyde and the p-toluene acid in respect to the mass of the present terephthalic acid at the temperature from 260°С up to 320°С and the pressure sufficient for maintaining the solution in the liquid phase and introduction of the solution in contact with hydrogen at presence of the catalytic agent of hydrogenation with production of the solution of the hydrogenated product; (9) loading of the solution of the stage (8) into the crystallization zone including the set of the connected in series crystallizers, in which the solution is subjected to the evaporating cooling with the controlled velocity using the significant drop of the temperature and the pressure for initiation of the crystallization process of the terephthalic acid, at the pressure of the solution in the end of the zone of the crystallization is atmospheric or below; (10) conduct condensation of the dissolvent evaporated from the crystallizers and guide the condensed dissolvent back into the zone of the crystallization by feeding the part of the condensed dissolvent in the line of removal of the product of the crystallizer, from which the dissolvent is removed in the form of the vapor; and (11) conduct separation of the solid crystalline terephthalic acid containing less than 150 mass ppm of the p-toluene acid in terms of the mass of the terephthalic acid by separation of the solid material from the liquid under the atmospheric pressure. The method allows to obtain the target product in the improved crystalline form.

EFFECT: the invention ensures production of the target product in the improved crystalline form.

8 cl, 3 tbl, 2 dwg, 3 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to the improved method for isolating crystalline terephthalic acid comprising less 150 mas. p. p. per million (ppm) of p-toluic acid with respect to weight of terephthalic acid. Method involves the following steps: (1) preparing a solution containing from 10 to 35 wt.-% of dissolved terephthalic acid wherein from 150 to 1100 ppm of p-toluic acid is dissolved with respect to mass of terephthalic acid at temperature from 260°C to 320°C and under pressure providing maintaining the solution in liquid phase; (2) charge of solution from step (1) to crystallization zone comprising multitude amount of associated crystallizers wherein the solution is subjected for cooling at evaporation at the controlled rate by the moderate pressure and temperature reducing resulting to crystallization of terephthalic acid and wherein the solution pressure at the end of crystallization zone is equal to atmosphere pressure or lower; (3) condensation of solvent evaporated from crystallizers and recovering the condensed solution to the crystallization zone to place of descending flow from crystallizer wherein solvent is removed by evaporation, and (4) isolation of solid crystalline terephthalic acid comprising less 150 ppm of p-toluic acid with respect to the terephthalic acid mass by separation of the phase liquid-solid substance under atmosphere pressure. The advantage of method is preparing the end product in improved crystalline form and carrying out the process under atmosphere pressure or pressure near to atmosphere pressure.

EFFECT: improved method of crystallization.

3 cl, 1 dwg, 1 tbl, 2 ex

FIELD: crystal growing.

SUBSTANCE: invention relates to adipic acid crystals and treatment thereof to achieve minimum crystal caking. Crystals are prepared by crystallization of adipic acid from aqueous medium or between treating it with aqueous solution. Crystals are then subjected to ripening stage, that is crystals are held at temperature between 10 and 80°C until content of exchangeable water in crystals falls below 100 ppm, while using an appropriate means to maintain ambient absolute humidity at a level of 20 g/m3. Renewal of ambient medium is accomplished by flushing crystal mass with dry air flow having required absolute humidity. Means to maintain or to lower absolute humidity contains moisture-absorption device placed in a chamber. Content of exchangeable water in crystals is measured for 300 g of adipic acid crystals, which are enclosed in tightly sealed container preliminarily flushed with dry air and containing 2 g of moisture absorbing substance. In chamber, temperature between 5 and 25°C is maintained for 24 h. Content of water will be the same as amount of water absorbed by absorbing substance per 1 g crystals. Total content of water exceeds content of exchangeable water by at least 20 ppm.

EFFECT: minimized caking of crystals and improved flowability.

13 cl, 5 ex

The invention relates to an improved method of reducing the content of 4-carboxybenzene in the production of terephthalic or 3-carboxymethylthio in the production of isophthalic acid, comprising: (a) dissolving crude terephthalic acid or crude isophthalic acid in a solvent at a temperature of from 50 to 250With obtaining a solution; (b) crystallization of the purified acid from this solution by reducing the temperature and/or pressure; (C) the Department specified crystallized terephthalic acid or isophthalic acid from the solution; (d) adding an oxidant to the reactor oxidation carboxyanhydride for oxidation specified filtered solution of stage (C), leading to the transformation of 4-carboxybenzene or 3-carboxymethylthio in terephthalic acid or isophthalic acid; (e) evaporating the solvent from this solution from step (d); (f) cooling the concentrated solution from step (e) for crystallization additional quantities of purified terephthalic acid or isophthalic acid and filtering the specified slurry and recycling the most part, the mother liquor from step (f) in the devices is

The invention relates to an improved method of processing the reaction mixture obtained by direct oxidation of cyclohexane to adipic acid, in liquid phase, in a solvent and in the presence of dissolved in the reaction medium, catalyst, including decantation two liquid phases: upper non-polar phase containing mainly unreacted cyclohexane, and the lower polar phase containing mainly solvent, adipic acid and the resulting acid, the catalyst and other reaction products and unreacted hydrocarbons, distillation of the lower polar phase or, if necessary, the entire reaction mixture with obtaining, on the one hand, distillate, containing, at least a part of the most volatile compounds such as unreacted cyclohexane, the solvent, the intermediate reaction products and water, and, on the other hand, residue from distillation, containing adipic acid and the resulting carboxylic acid, the catalyst, and the method includes a step of adding to the residue after distillation of the organic solvent in which adipic acid has a solubility less than or equal to 15 wt

The invention relates to an improved method of isolation and purification of adipic acid, used for the production of polyamide-6,6 or polyurethanes, which consists in treating the reaction mixture obtained by direct oxidation of cyclohexane to adipic acid by molecular oxygen in an organic solvent and in the presence of a catalyst, removing by-products from the reaction mixture and the adipic acid by crystallization, and before adipic acid from the reaction environment carry out consistently the following operations: the decantation of the two phases of the reaction medium with the formation of the upper organic the cyclohexane phase, containing mainly cyclohexane, and the lower phase, containing mainly the solvent, the resulting dicarboxylic acid, the catalyst and other reaction products and unreacted cyclohexane; distillation bottom phase to separate, on the one hand, distillate containing at least a part of the most volatile compounds, such as organic solvent, water and unreacted cyclohexane, cyclohexanone, cyclohexanol, complex cyclohexylamine esters and possibly lactones, and, with the pin acid from residue from distillation by means of crystallization and thus obtained crude adipic acid is subjected in aqueous solution purification by hydrogenation and/or oxidation with subsequent crystallization and recrystallization of the purified adipic acid in water

The invention relates to an improved process for the preparation of terephthalic and isophthalic acids

The invention relates to an improved method for producing isophthalic acid used in copolymerization ways of producing fibers, films, plastic bottles and structures made of polyester resin, which consists in the oxidation of metaxalone in the reaction solvent to obtain a liquid dispersion

FIELD: chemistry.

SUBSTANCE: principle refers to the method of producing olefin oxide, method of application of the produced olefin oxide and the production of 1,2-diol or simple ether 1-,2-diol and catalytic composition. The mentioned catalytic composition for the production of olefin oxide contains silver and activating agent, that consists of an alkaline metal on a bearer where the activating alkaline metal contains potassium whose quantity is not less than 5 mcmol/g of metal relative to the mass of the catalytic composition and not less than 1 mcmol/g alkaline metal from the group that contains lithium, sodium and there mixtures in which the mentioned bearer contains calcium carbonate joined with silver. The relative mass of silver: calcium carbonate is 1:5 to 1:100, and the unit surface area of the bearer is from 1 m/g to 20 m/g, and the apparent porosity of the bearer is 0.05 ml/g to 2 ml/g. The explained method of producing olefin oxide, include interaction of olefin, that has 3 or more carbon atoms, with oxygen in the presence of the above mentioned catalytic system, and the method of producing 1,2-diol or simple ether 1,2-diol, in which the olefin oxide is produced from the explained method.

EFFECT: increasing of selectivity, activity and stability of catalyst.

10 cl, 5 tbl, 37 ex

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