Method of methyl methacrylate purification

FIELD: chemistry.

SUBSTANCE: invention relates to a method of methyl methacrylate (MMA) purification, which includes realisation of contact of a liquid MMA, containing admixtures, with a sulphonic acid resin in the presence of formaldehyde or an acceptable source of methylene or ethylene of formula I, as is determined below, where R5 and R6 are independently selected from C1-C12 hydrocarbons or H; X represents O; n is an integer number from 1 to 100; and m has a value of 1 or 2, and in which the sulphonic acid resin is optionally, at least, partially, deactivated.

EFFECT: method makes it possible to remove admixtures of an aldehyde type, dienes, trienes with high efficiency.

18 cl, 20 tbl, 1 dwg, 8 ex

 

The present invention relates to a method of treatment, in particular to a method of purification of methyl methacrylate (MMA).

MMA is a well - known chemical compound, which has wide application, but mainly it is used as a monomer in the production of polymethyl methacrylate (PMMA). PMMA is often given in the form of thin sheets from which it is possible to mould a variety of items required for a specific application.

To obtain PMMA is important to use MMA highest degree of purity, because even a low content of impurities can lead to the product of PMMA having a cloudy, opaque or faded appearance. In addition, the low content to primesti in MMA can lead to changes in the structural properties of products made of PMMA, which can have undesirable effects. Thus, it is important to have the possibility of obtaining MMA, PMMA monomer, the highest degree of purity, to try to prevent these problems.

MMA can be obtained in many ways, for example by reaction of acetonecyanohydrin, methanol and concentrated sulfuric acid; the oxidation of tertiary butyl alcohol in methacrolein, and then methacrylic acid followed by esterification with methanol; alternatively, catalyzed reactions, as described in patent EP 1073517. Such reactions, and many others, known in the literature is the ur, give the thread MMA, which typically contains impurities that can create the problems discussed above, when MMA is polymerized with the formation of PMMA. Generally, trying to clear the stream MMA before polymerization. Known separation of impurities, which are significantly different from MMA at the boiling point by distillation. However, this method of separation is difficult to implement, if impurities and MMA have similar boiling point.

Japanese patent 58-183641 describes the use of acidic catalyst for the treatment of impurities in the crude methyl methacrylate.

Japanese patent application 63-127952 proposes to use compounds containing sulfonylurea group for processing high purity methyl methacrylate.

U.S. patent 4625059 (patent Mitsubishi Petrochemical) describes the use of acidic ion-exchange resin in a fixed bed for separating impurities from crude MMA.

Thus, crude MMA obtained in various ways, contains quite a variety of impurities, which are difficult to separate by distillation. MMA obtained by condensation of formaldehyde with methylpropionate, additionally contains other is not yet certain impurities, such as color-forming compounds which are not described in the previously known methods of obtaining MMA.

The aim of the aspects of the present invention is to offer the solutions of the problem of separating data or other impurities when cleaning MMA.

According to the first aspect of the present invention, it is proposed a method of purification of methyl methacrylate (MMA), consisting in contact containing liquid impurities MMA sulfoxylates resin in the presence of formaldehyde or a suitable source of methylene or ethylene of the formula I, as defined below:

where R5and R6independently selected from a hydrocarbon, C1-C12preferably the alkyl, alkenyl or aryl (C1-C12as defined in the present invention, or H, preferably the alkyl (C1-C10or H, most preferably alkyl, C1-C6or H, especially methyl or H;

X represents O or S, preferably O;

n is an integer from 1 to 100, preferably from 1 to 10, preferably from 1 to 5, especially 1-3;

and m has a value of 1 or 2, preferably 1.

In the most preferred embodiment, the connection I get from formaldehyde in the presence of methanol and/or water. In this case, the compound I can be identified as suitable source of formaldehyde. For the avoidance of doubt suitable source of formaldehyde means any equilibrium composition, which can serve as a source of formaldehyde. Its examples include, without limitation, matilal (1,1 - dimethoxymethane), polyoxymethylenes -(CH2-O)i-where i=1-100, Faure, the'alene (formaldehyde, methanol, water) and other equilibrium compositions, for example a mixture of formaldehyde, methanol and methylpropionate.

Typically, the polyoxymethylenes - highest formal formaldehyde and methanol CH3-O-(CH2-O)i-CH3("formal-i), where i=1-100, preferably 1 to 5, especially 1 to 3, or other polyoxymethylenes containing at least one Demetriou end group. Thus, the source of formaldehyde can also serve as Polyoxymethylene R1-O-(CH2O)iR2where R1and R2may be the same or different groups, and at least one selected from alkyl groups of C2-C10for example, R1=isobutyl and R2=methyl.

Preferably, the formaldehyde or the amount of formaldehyde that can be distinguished from a suitable source of formaldehyde is present in a concentration of 0.01-0.1% by weight of liquid MMA.

Preferably, a suitable source of formaldehyde selected from 1,1-dimethoxymethane, the highest formula formaldehyde and methanol, for example CH3-O-(CH2-O)i-CH3where i=2 or more, as indicated above, formalin or mixtures containing formaldehyde, methanol and methylpropionate.

Preferably, the term "formaldehyde" means a mixture of formaldehyde, methanol and water in the ratio of 25-65:0,01-25:25-70 wt.%. Preferably, the term "formaldehyde" means CME is ü formaldehyde, methanol and water in the ratio of 30-60:0,03-20:35-60 wt.%.

Most preferably, the term "formaldehyde" means a mixture of formaldehyde, methanol and water in the ratio of 35-55:0,05-18:42-53% wt.

Preferably, a mixture of formaldehyde, methanol and methylpropionate contains less than 5 wt.%. water.

Preferably, the mixture of formaldehyde, methanol and methylpropionate contains less than 1% wt. water. Most preferably, a mixture of formaldehyde, methanol and methylpropionate contains 0.1 to 0.5% wt. water.

Preferably, a suitable source of formaldehyde has a boiling point in the range from 69 to 73°C at an absolute pressure of 0.75 bar.

Preferably, formaldehyde or its source is mixed with the contaminated liquid MMA before contact with sulfoxylates resin. Typically, in a continuous or semi-continuous process, the flow of contaminated liquid MMA is mixed with a stream containing formaldehyde or its source, with the formation of the combined liquid stream prior to contact with sulfoxylates resin. Formaldehyde, thus, is present in the combined liquid stream at a concentration of 0.01-0.1 wt.%.

As an alternative or Supplement, the source of formaldehyde may be present as an impurity in MMA, preferably as an admixture with close boiling points, before contact with sulfoxylates resin. In such cases, the transmission of Zagreb is being emitted by contaminated MMA through the layer of ion exchange resin will remove or reduce the concentration of the source of formaldehyde and/or changes in the composition of the heavy or light component, which can be easily separated from MMA by distillation.

Preferably, the admixture with close boiling temperature, which is present in MMA, is pointless-2 (CH3-O-(CH2-O)2-CH3).

Preferably a lightweight component with respect to the separation from MMA is dimethoxymethane. Preferably dimethoxymethane separated from MMA by distillation.

Preferably, the cleaning method of the present invention is carried out at a temperature of 25-100°C. Preferably, this method is carried out at a temperature of 40-90°C. More preferably, this method is carried out at a temperature of 50-80°C. Most preferably, this method is carried out at a temperature of 50-70°C.

Preferably sulfonylurea resin is compacted layer. Preferably, sulfonylurea resin contains strongly acidic macroporous resin-based polymer. Most preferably, sulfonylurea resin is a cross-linking polystyrene resin in the form of spherical beads in size from 0.4 to 1.64 mm, which contains 0.5 to 3.0 mEq/l sulfoxylate groups (preferably 0.7 to 2.5 mEq/l) and has a porous structure with an average pore diameter of from 15 to 90 nm (preferably 20-70 nm), the specific surface area of from 15 to 100 m2/g (preferably 20-80 m2/g) and specific pore volume, measured by the extent the Yeni water retention wet resin, from 30 to 80%, preferably 40-70%). Preferably, the acidic ion-exchange resin is macrostate resin.

Preferably, in this method of cleaning is also present at least one ester of carboxylic acid. Preferably, the ester of carboxylic acid is chosen from methyl, ethyl, or propyl ether any carboxylic acid C2-C6with a linear or branched chain. Preferably, the ester, at least one carboxylic acid selected from methyl or ethyl ester of any carboxylic acid C2-C4with a linear or branched chain. Examples of suitable esters of carboxylic acids include, without limitation, methylpropionate, ethylpropane, propylphosphonate, methylbutanoate, methylisobutyl, ethylbutanal, propylmalonate, butylborane. In the preferred embodiment, this cleaning method also includes methylpropionate or methylisobutyl.

Typically, in a continuous or semi-continuous process, at least one ester of carboxylic acid is already present in the stream of contaminated liquid MMA before contact with sulfoxylates resin. Therefore, in such scenarios, the implementation, as a rule, at least one ester of carboxylic acid is part of the war of the liquid stream.

Typically, the impurities have a boiling point which makes inefficient separation by distillation. Typically, the temperature difference between the boiling impurities and MMA does not exceed 15°C. Often the temperature difference between the boiling impurities and MMA does not exceed 10°C. In most cases, the temperature difference between the boiling impurities and MMA does not exceed 5°C. Typically, the boiling point impurities and MMA are roughly the same, i.e. vary within 1-2°C. Impurities boiling point which in pure form is different from the boiling point of MMA is more than 15° and which exhibit non-ideal behavior by distillation mixed with MMA and other impurities, it is difficult to separate from MMA distillation due to physical effects. Examples of such physical effects include the formation of azeotropic mixtures with a high or a low boiling point.

It is shown that the present invention is particularly useful for separating some of the impurities from the contaminated liquid MMA. It is shown that these impurities may contain Isobutyraldehyde or connection, which allocates Isobutyraldehyde when exposed sulfoxylates ion-exchange resin. Examples of such compounds include mono - or diacetate of Isobutyraldehyde and branched or linear alcohol C1-C6in particular 2,2-dimethoxypropane and metallolomnogo alcohol.

The Department is giving Isobutyraldehyde using a combination of formaldehyde and resin profitable despite the fact that Isobutyraldehyde separated from MMA as an impurity with a lower boiling point.

Department of Isobutyraldehyde in the column for low-boiling impurities causes the risk of initiating polymerization of a mixture of Isobutyraldehyde and oxygen in the upper shoulder straps columns for low-boiling impurities, which contain mainly MMA and should be oxygenated for the effectiveness of the stabilizers of polymerization.

In addition, recirculation of Isobutyraldehyde causes its slow conversion to Isobutanol over the catalyst. Isobutyl alcohol gets into the net product of MMA and reduces its quality, but also creates problems in thin sheets, because it reacts with the initiators of polymerization, thereby increasing the consumption data of initiators necessarily turn unreacted and reacted with isobutyl alcohol) forms. This problem occurs when the production of polymer (Plexiglas) aquarium quality and in some other cases, which requires a very low content of initiators.

Other successfully separated impurities are randomly substituted diene C4-C20. It is shown that the present invention is particularly useful for the separation of such dienes. Useful substituted dianam that can be separated include diene C4-C20containing from about the nogo up to four alkyl substituents C 1-C6for example mono - or dialkylamide. Examples of dienes include, without limitation, any of the following: 2,5-dimethyl-2,4-hexadiene; 2,5-dimethyl-1,5-hexadiene, 2-methyl-1,5-hexadiene; TRANS-2-methyl-2,4-hexadien; CIS-2-methyl-2,4-hexadiene; 2-methyl-3,5-hexadiene; 2-methyl-1,3-hexadiene; 2,5-dimethyl-1,3-hexadiene and 1,6-heptadiene.

In addition, impurities may also contain arbitrarily substituted triene C6-C20. Examples of trienol include, without limitation, any of the following: heptatriene and cycloheptatrien.

It is shown that the present invention is particularly effective for the separation of dienes C4-C20or trienol C6-C20with internal analnyj carbon atoms with one or more substituents, preferably alkyl, preferably with alkyl substituents C1-C6or end analnyj carbon atoms with two substituents, preferably alkyl, preferably with alkyl substituents C1-C6because aniline carbon atoms can form tertiary carbocations. It is most preferable to use the present invention to separate arbitrarily substituted dienes C4-C20as defined above. In particular, it is preferable to separate dianam of the present invention include: TRANS-2-methyl-2,4-hexa the yen; CIS-2-methyl-2,4-hexadiene; 2-methyl-3,5-hexadiene; 2-methyl-1,3-hexadiene; 2,5-dimethyl-1,3-hexadiene and 1,6-heptadiene, in particular, TRANS-2-methyl-2,4-hexadien and CIS-2-methyl-2,4-hexadien.

Other impurities that can be removed by the method according to the present invention will also typically contain arbitrarily substituted unsaturated aldehydes and ketones. Examples of such aldehydes or ketones are compounds R C=OR", where R' may be hydrogen atom, optionally substituted alkyl, alkenyl or aryl, preferably alkyl, C1-C6alkenyl C1-C6or aryl, and R" may be arbitrarily substituted alkyl, alkenyl or aryl, preferably alkyl, C1-C6alkenyl C1-C6or phenyl.

In addition, 2-methylene-3-butenyl may also be present and removed by the method according to the present invention. This admixture otherwise may be mainly coupler in MMA.

Other suitable additives include: Divinington, ethylvanillin, diethylketone, ethylisopropylamine, 3-methylene-1-HEXEN-4-one, methacrolein, Isobutanol, toluene and pentenal, for example 3-pentenal. Other preferred impurities that can be removed by the method according to the present invention include ethylvanillin and Divinington.

Accordingly, the present invention is particularly useful for the Otdelenia TRANS-2-methyl-2,4-hexadiene, CIS-2-methyl-2,4-hexadiene, ethylvanillin and diphenylmethane.

Suitable method of preparation of MMA before cleaning in contact with formaldehyde or a source of methylene or ethylene is in contact methylpropionate with a suitable source of methylene of formula I, as defined below:

where R5and R6independently selected from a hydrocarbon, C1-C12preferably the alkyl, alkenyl or aryl (C1-C12as defined in the present invention, or H, preferably the alkyl (C1-C10or H, most preferably alkyl, C1-C6or H, especially methyl or H;

X represents O or S, preferably O;

n is an integer from 1 to 100, preferably from 1 to 10, preferably from 1 to 5, especially 1-3;

and m=1;

in the presence of a suitable catalyst and optionally in the presence of alcohol.

This method can be carried out in the presence of at least one suitable stabilizer. Preferably, at least one stabilizer can be selected from hydroquinone, p-methoxyphenol, topanol-(2-tert-butyl-4,6-dimethylphenol) or fenotiazina.

The term "alkyl" when used in the present invention means, unless otherwise specified, alkyl (C1-C10for example, methyl, ethyl, through butil the th, pentelow, hexoloy or heptylene group. Unless otherwise indicated, the alkyl groups may, when there is a sufficient number of carbon atoms, be linear or branched (especially preferred branched groups are tert-bucilina and ISO-propyl), saturated, cyclic, acyclic or part cyclic/acyclic, unsubstituted, substituted or terminated by one or more substituents, which include a halogen atom, cyano, a nitro-group or or19, OC(O)R20C(O)R21C(O)OR22, NR23R24C(O)NR25R26, SR29C(O)SR30C(S)NR27R28, unsubstituted or substituted aryl, or unsubstituted or substituted heterocycle, where each of the groups R19-R30independently represents a hydrogen atom, halogen atom, unsubstituted or substituted aryl or unsubstituted or substituted alkyl, or, in the case of R21, a halogen atom, a nitro-group, a cyano or amino group, and/or a carbon chain interrupted by one or more (preferably less than 4) atoms of oxygen, sulfur, silicon or silane or diallylmalonate group or combinations thereof.

The term "Ar" or "aryl" when used in the present invention means containing from five to ten members, preferably five to eight members Carbo is ilycheskie aromatic or psevdogeometricheskie group, for example, phenyl, cyclopentadienyls and intenally anions and naphthyl, whereby these groups can be unsubstituted or contain one or more substituents, including unsubstituted or substituted aryl, alkyl (itself this group can be unsubstituted or substituted, or limit, as defined in this invention), heterocycle (this group may be unsubstituted or substituted, or limit, as defined in the present invention), a halogen atom, a cyano, a nitro-group or or19, OC(O)R20C(O)R21C(O)OR22, NR23R24C(O)NR25R26, SR29C(O)SR30C(S)NR27R28where each of the groups R19-R30independently represents a hydrogen atom, unsubstituted or substituted aryl or alkyl (itself this group can be unsubstituted or substituted, or limit, as defined in this invention), or, in the case of R21, a halogen atom, a nitro-group, a cyano or amino group.

The term "alkenyl" when used in the present invention means alkenyl C2-C10and includes atenilol, propenyloxy, butenyloxy, pantanillo and hexenyl group. Unless otherwise stated, alkeline groups may, when there is a sufficient number of carbon atoms, be linear or branched, cyclic, acyclic ilization cyclic/acyclic, unsubstituted, substituted or terminated by one or more substituents, which include a halogen atom, cyano, a nitro-group or or19, OC(O)R20C(O)R21C(O)OR22, NR23R24C(O)NR25R26, SR29C(O)SR30C(S)NR27R28, unsubstituted or substituted aryl, or unsubstituted or substituted heterocycle, where each of the groups R19-R30independently represents a hydrogen atom, halogen atom, unsubstituted or substituted aryl or unsubstituted or substituted alkyl, or, in the case of R21, a halogen atom, a nitro-group, a cyano or amino group, and/or a carbon chain interrupted by one or more (preferably less than 4) atoms of oxygen, sulfur, silicon or silane or diallylmalonate group, or combinations thereof.

The atoms of halogen, which are the above groups may be substituted or completed include fluorine, chlorine, bromine and iodine.

The term "heterocycle", when used in the present invention, means containing from four to twelve members, preferably four to ten members of a cyclic system, the cycles which contain one or more heteroatoms, including the nitrogen atoms, oxygen, sulfur and combinations thereof, and these cycles may not contain or may contain one or more double bonds or may b the th non-aromatic, partially aromatic or fully aromatic in nature. Data cyclic system may be monocyclic, bicyclic or paired. Each heterocyclic group, as defined in the present invention may be unsubstituted or contain one or more substituents including a halogen atom, a cyano, a nitro-group, oxoprop, alkyl (itself this group can be unsubstituted or substituted, or limit, as defined in this invention), -OR19, -OC(O)R20, -C(O)R21, -C(O)OR22, -NR23R24, -C(O)NR25R26, -SR29, -C(O)SR30, -C(S)NR27R28, unsubstituted or substituted aryl, or unsubstituted or substituted heterocycle, where each of the groups R19-R30independently represents a hydrogen atom, halogen atom, unsubstituted or substituted aryl or unsubstituted or substituted alkyl, or, in the case of R21, a halogen atom, a nitro-group, amino group or cyano. Thus, the term "heterocycle" means groups such as arbitrarily substituted azetidines, pyrrolidines, imidazolyl, indolyl, furanyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, thiadiazolyl, triazolyl, oxadiazolyl, tetrazolyl, pyridazinyl, morpholinyl, pyrimidinyl, pyrazinyl, chinoline, ethenolysis, piperidinyl, pyrazolyl and Pieper is sinil. The substitution of the heterocycle can occur when the carbon atom of this heterocycle or, to the extent possible, in one or more heteroatoms.

"Heterocyclic" groups may also be in the form of N-oxide.

The term "heteroatom" as used in the present invention means the atoms of nitrogen, oxygen, sulfur or combinations thereof.

In a continuous process, after a period of, say, a few months, the effectiveness sulfoxylates resin can be reduced by approximately 20% compared with the efficiency of fresh resin. Such a resin is often referred to as "deactivated". But then it was unexpectedly discovered that the presence of a suitable source of formaldehyde according to the present invention makes "deactivated" resin to separate impurities with a speed close to the speed of the fresh resin.

Thus, according to the second aspect of the present invention, it is proposed a method of purification of methyl methacrylate (MMA), consisting in contact containing liquid impurities MMA sulfoxylates resin in the presence of formaldehyde or a suitable source of methylene or ethylene of the formula I, as defined below:

where R5and R6independently selected from a hydrocarbon, C1-C12preferably from alkyl, alkenyl or aryl (C1-C12how suitable is but in the present invention, or H, preferably from alkyl (C1-C10or H, most preferably from alkyl (C1-C6or H, especially methyl or H;

X represents O or S, preferably O;

n is an integer from 1 to 100, preferably from 1 to 10, preferably from 1 to 5, especially 1-3;

and m has a value of 1 or 2, preferably 1, and sulfonylurea resin at least partially deactivated.

In a particularly preferred embodiment, the connection I get from formaldehyde in the presence of methanol and/or water. In this case, the compound I can be identified as suitable source of formaldehyde. The expression "sulfonylurea resin at least partially deactivated" means that the effectiveness sulfoxylates resin decreased (compared with fresh resin) as a result of previous exposure to the resin pollutants, including those present in the original cleared the stream, such as a contaminated liquid stream MMA. Preferably, at least partially deactivated sulfonylurea resin has an efficiency of less than 99.9% in comparison with the efficiency of fresh resin. Preferably, at least partially deactivated sulfonylurea resin has an efficiency less than 99% compared to the efficiency of the fresh resin; as a rule, the effectiveness is m is it 95%, more than 75%, in particular less than 50%.

Preferably, at least partial deactivation is related to the ability sulfoxylate resins to react with at least one diene. For example, preferably at least partially deactivated sulfonylurea resin has an efficiency less than 50% in the reaction of at least one diene compared with the efficiency of fresh tar.

According to a third aspect of the present invention, it is proposed a methacrylate, such as liquid MMA containing one or more impurities referred to in the present invention, which has been in contact with sulfoxylates resin in the presence of formaldehyde or a suitable source of methylene or ethylene of the formula I, as defined below:

where R5and R6independently selected from a hydrocarbon, C1-C12preferably from alkyl, alkenyl or aryl (C1-C12as defined in the present invention, or H, preferably from alkyl (C1-C10or H, most preferably alkyl, C1-C6or H, especially methyl or H;

X represents O or S, preferably O;

n is an integer from 1 to 100, preferably from 1 to 10, preferably from 1 to 5, especially 1-3;

and m has a value of 1 or 2, preferably 1, when in fluid the phase.

According to the fourth aspect of the present invention, it is proposed a polymer containing methyl methacrylate residues, and the data of methyl methacrylate residues were in contact with sulfoxylates resin in the presence of formaldehyde or a suitable source of methylene or ethylene of the formula I, as defined below:

where R5and R6independently selected from a hydrocarbon, C1-C12preferably from alkyl, alkenyl or aryl (C1-C12as defined in the present invention, or H, preferably from alkyl (C1-C10or H, most preferably alkyl, C1-C6or H, especially methyl or H;

X represents O or S, preferably O;

n is an integer from 1 to 100, preferably from 1 to 10, preferably from 1 to 5, especially 1-3;

and m has a value of 1 or 2, preferably 1, when in the liquid phase monomer.

Preferably, the contaminated MMA according to the present invention is obtained by condensation of formaldehyde with methylpropionate. It is shown that the present invention is particularly useful for separating impurities from a liquid MMA obtained in this way. Typically, contaminated MMA cleaning method of the present invention is obtained by condensation of formaldehyde with methylpropionate in the presence of prigodin the th basic catalyst and, optional, methanol, to prevent the formation of acid. Suitable basic catalyst for the condensation reaction is silicon dioxide, doped with alkaline metal, for example containing cesium ions silicon dioxide (Cs+/SiO2). In such cases, suitable for use silicon dioxide is preferably a porous silica with a large specific surface, such as silica gel, precipitated silica and sintered pyrogenic silica. The preferred content of alkali metal in the catalyst on the basis of silicon dioxide is in the range from 1 to 10% wt. (in terms of metal).

All signs contained in the present invention, can be combined with any of the above aspects, in any combination.

Hereinafter the present invention will be illustrated in the following examples with reference to the drawing, in which:

Figure 1 contains a graph of the Department of diphenylmethane depending on the content of formaldehyde in the source material.

Examples

Example 1

Washed by the stream of methanol, 100 g of the water-wetted strong sulfoxylates ion-exchange resin Lewatit 2314 (supplier Lanxess) in a glass column filled with resin, with a speed of 1 layer volume per hour up until the original brown eluent didn't become colorless in appearance. Then the resin is washed clean of MMA to reduce the concentration of methanol to 100 h/million Were placed 20 g of the specified resin in a three-neck round bottom flask with magnetic stirrer, thermometer and reflux condenser with a water jacket. Into the flask were placed 50 ml sample of pure MMA with the addition of 100 ppm of 2-methyl-1,5-hexadiene. The flask was placed in a preheated oil bath and samples were taken from the flask by pipette after a certain period of time. The same batch of resin was used for each experiment. Samples were analyzed on a gas chromatograph Varian GC equipped with a capillary column CPSil 1701. 2-methyl-1,5-hexadien quickly someresource with the formation of 2-methyl-2,5-hexadiene. Then this compound slowly disappeared with the formation of 2-methyl-2,4-hexadiene. The experiment was carried out three times at 70, 50 and 30°C. the Mass percentages of all components are given in tables 1, 3 and 5.

Example 2

Example 1 was repeated, but in this case, 1000 or 7000 ppm 1,1-dimethoxymethane was added to a solution of MMA before heating. Mass percentages of all components are given in tables 2, 4 and 6.

Example 3

Example 1 was repeated, except that a mixture containing 100 ppm of 2,5-dimethyl-1,5-hexadiene and 2,5-dimethyl-2,4-hexadiene used instead of 100 h/million 2-methyl-1,5-hexadiene. Mass percentages of all components at three different temperatures are shown in tables 7, 9 and 11.

Example 4

Example 3 was repeated, C is the exception that that 1000 or 7000 ppm 1,1-dimethoxymethane was added to a solution of MMA before heating.

Mass percentages of all components at each temperature heating are shown in tables 8, 10 and 12.

In tables 7-12 shows the amount of 2,5-dimethyl-2,4-hexadiene present through different time periods and at different temperatures in the presence and in the absence of 1,1-dimethoxymethane.

Table 1
70°C, 0 ppm 1,1-dimethoxymethane
ComponentTime min
0510204060
2-methyl-1,5-hexadien0,0109%0,0000%0,0000%0,0000%0,0000%0,0000%
2-methyl-2,5-hexadien0,0000%0,0083%0,0072%0,0052%0,0031%0,0014%
TRANS-2-methyl-2,4-hexadien0,0000%0,0005%0,0019%0,0022%0,0027%0,0025%
CIS-2-methyl-2,4-hexadien0,0000%0,0000%0,0000%0,0000%0,0000%0,0000%

Table 2
70°C, 1000 ppm 1,1-dimethoxymethane
ComponentTime min
0510204060
2-methyl-1,5-hexadiento 0.0117%0,0007%to 0.0004%0,0005%0,0005%0,0006%
2-methyl-2,5-hexadien0,0000%0,0054%0,0027%0,0011% 0,0009%0,0006%
TRANS-2-methyl-2,4-hexadien0,0000%0,0000%0,0000%0,0000%0,0000%0,0000%
CIS-2-methyl-2,4-hexadien0,0000%0,0000%0,0000%0,0000%0,0000%0,0000%

0,0072%
Table 3
50°C, 0 ppm 1,1-dimethoxymethane
ComponentTime min
0510204060
2-methyl-1,5-hexadien0,0109%0,0003%to 0.0004%0,0005%0,0005%0,0000%
2-methyl-2,5-hexadien0,0000%0,0076%0,0068%0,0065%0,0049%
TRANS-2-methyl-2,4-hexadien0,0000%0,0000%0,0000%0,0001%0,0003%0,0007%
CIS-2-methyl-2,4-hexadien0,0000%0,0000%0,0000%0,0000%0,0000%0,0000%

Table 4
50°C, 1000 ppm 1,1-dimethoxymethane
ComponentTime min
0510204060
2-methyl-1,5-hexadien0,0111%0,0000%0,0000%0,0000%0,0000%0,0000%
2-methyl-2,5-hexadien 0,0000%0,0062%0,0047%0,0031%0,0014%0,0008%
TRANS-2-methyl-2,4-hexadien0,0000%0,0000%0,0000%0,0000%0,0000%0,0000%
CIS-2-methyl-2,4-hexadien0,0000%0,0000%0,0000%0,0000%0,0000%0,0000%

Table 5
30°C, 0 ppm 1,1-dimethoxymethane
ComponentTime min
0510204060
2-methyl-1,5-hexadien0,0132%is 0.0002%is 0.0002%is 0.0002%0,002% 0,0001%
2-methyl-2,5-hexadien0,0000%0,0067%0,0070%0,0065%0,0065%0,0063%
TRANS-2-methyl-2,4-hexadien0,0000%0,0000%0,0000%0,0000%0,0000%0,0000%
CIS-2-methyl-2,4-hexadien0,0000%0,0000%0,0000%0,0000%0,0000%0,0000%

Table 6
30°C, 7000 ppm 1,1-dimethoxymethane
ComponentTime min
0510204060
2-methyl-1,5-hexadien0,0121%0,0007% is 0.0002%is 0.0002%0,0000%0,0000%
2-methyl-2,5-hexadien0,0000%0,0064%0,0052%0,0031%0,0009%0,0000%
TRANS-2-methyl-2,4-hexadien0,0000%0,0000%0,0000%0,0000%0,0000%0,0000%
CIS-2-methyl-2,4-hexadien0,0000%0,0000%0,0000%0,0000%0,0000%0,0000%

In the absence of 1,1-dimethoxymethane 2-methyl-1,5-dimethylhexane quickly isomerizes 2-methyl-2,5-hexadien and then slowly becomes partially 2-methyl-2,4-hexadien. In the presence of 1,1-dimethoxymethane for the isomerization process should prompt removal of 2-methyl-2,5-hexadiene, and the flask is not detected 2-methyl-2,4-hexadien.

Table 7
30°C, 0 ppm 1,1-dimethoxymethane
ComponentTime min
0510204060
2,5-dimethyl-1,5-hexadien0,0034%0,0000%0,0049%0,0027%0,0035%0,0034%
2,5-dimethyl-2,4-hexadien0,0000%0,0000%0,0000%0,0060%0,0054%0,0044%

Table 8
30°C, 7000 ppm 1,1-dimethoxymethane
ComponentTime min
0510204060
2,5-dimethyl-1,5-hexadien0,0069%0,0023% 0,0024%0,0027%0,0023%0,0025%
2,5-dimethyl-2,4-hexadien0,0082%0,0068%to 0.0039%0,0018%0,0000%0,0000%

Table 9
50°C, 0 ppm 1,1-dimethoxymethane
ComponentTime min
0510204060
2,5-dimethyl-1,5-hexadien0,0082%0,0006%0,0009%0,0008%0,0008%0,0011%
2,5-dimethyl-2,4-hexadien0,0088%0,0111%0,0119%0,0118%0,0120%to 0.0117%

Table 10
50°C, 1000 ppm 1,1-dimethoxymethane
ComponentTime min
0510204060
2,5-dimethyl-1,5-hexadien0,0057%0,0013%0,0016%0,0015%0,0017%0,0016%
2,5-dimethyl-2,4-hexadien0,0064%0,0090%0,0071%0,0047%0,0018%0,0013%

Table 11
70°C, 0 ppm 1,1-dimethoxymethane
ComponentTime min
0510204060
2,5-dimethyl-1,5-hexadien0,0024%0,0005%0,0006%0,0006%0,0010%0,0012%
2,5-dimethyl-2,4-hexadien0,0042%0,0133%0,0131%0,0124%0,0104%0,0096%

Table 12
50°C, 1000 ppm 1,1-dimethoxymethane
ComponentTime min
0510204060
2,5-dimethyl-1,5-hexadien0,0027%0,0013%0,0010%0,0008%0,0007%0,0003%
2,5-dimethyl-2,4-hexadien0,0049%0,0050%0,0027%0,0014% 0,0009%0,0006%

In the absence of 1,1-dimethoxymethane for rapid isomerization of 2,5-dimethyl-2,5-hexadiene 2,5-dimethyl-2,4-hexadien should be very slow decomposition of the latter. When 1,1-dimethoxymethane is present in solution, rapid decomposition of 2,5-dimethyl-2,4-hexadiene with the formation of another product.

The rate constants for first order reactions for the decomposition of 2-methyl-2,5-hexadiene and 2,5-dimethyl-2,4-hexadiene are shown in table 13 for each of the conditions.

Table 13
The reaction rate constant of the first order, with-1
Concentration
1,1-dimethoxymethane, h/million
30°C50°C70°C
The rate constants for first order reactions for the decomposition of 2-methyl-2,5-hexadiene00,00150,0070,0325
10000,0367 0,1147
70000,0581
The rate constants for first order reactions for the decomposition of 2,5-dimethyl-2,4-hexadiene00,00030,00630,0003
10000,03650,0812
70000,0878

Thus, the addition of 1,1-dimethoxymethane significantly affect the rate of decomposition as 2-methyl-2,5-hexadiene, and 2,5-dimethyl-2, 4-hexadiene.

Example 5

Used two samples of fresh resin Lewatit 2431:

A. Fresh resin

It was obtained by washing the resin with methanol containing 200 ppm of hydroquinone (GC), and then pure MMA containing 100 ppm GC.

B. Used resin

Used the sample, through which is passed a continuous stream of contaminated MMA for 12 days. Contaminated MMA received in the process of getting MMA condensation reaction of methylpropionate and formaldehyde.

The method according to example 1 examined two sample through the reaction mixture, with whom containing a series of polluted MMA and CIS - and TRANS-2-methyl-2,4-hexadien listed in table concentrations and 100 ppm GC at 50°C.

The concentrations of all substances listed in the following table 14.

Table 14
The exposure time, min
025102030
Fresh resin0 ppm 1,1-dimethoxymethaneTRANS-2-methyl-2,4-hexadien0,0035%0,0011%to 0.0004%is 0.0002%0,0000%0,0000%
CIS-2-methyl-2,4-hexadien0,0040%0,0003%0,0001%0,0001%0,0000%0,0000%
Used resin0 ppm 1,1-dimethoxymethanethe Rance-2-methyl-2,4-hexadien 0,0035%0,0022%0,0021%0,0016%0,0007%is 0.0002%
CIS-2-methyl-2,4-hexadien0,0040%0,0014%0,0008%0,0007%0,0003%0,0001%
Fresh resin+1000 ppm 1,1-dimethoxymethaneTRANS-2-methyl-2,4-hexadien0,0041%0,0008%0,0000%0,0000%0,0000%0,0000%
CIS-2-methyl-2,4-hexadien0,0015%to 0.0004%0,0000%0,0000%0,0000%0,0000%
Used resin+1000 ppm 1,1-dimethoxymethaneTRANS-2-methyl-2,4-hexadien0,0041%0,0001%0,0000% 0,0000%0,0000%0,0000%
CIS-2-methyl-2,4-hexadien0,0015%0,0000%0,0000%0,0000%0,0000%0,0000%

Changes in the concentration of 2-methylpentadiene over time is complicated by their being in equilibrium in the presence of acidic ion-exchange resin. Thus, the concentration of dienes summarized for the study of the kinetics of decomposition. It was found that their total concentration was decreased approximately exponentially with time. The rate constants of reactions of the first order received for the two resins with the addition of and in the absence of containing formaldehyde substances below in table 15.

Table 15
Kinetic comparisonFresh resinUsed resin
Without 1,1-dimethoxymethane0,50,09
With 1,1-dimethoxymethane0,80,9

For fresh resin found in approximately 50% increase in the speed Department when adding 1,1-dimethoxymethane. For the previously used resin, the speed of separation in the absence of 1,1-dimethoxymethane was very low and amounted to only 17% of the speed for the fresh resin. However, found a ten-fold increase in activity for the used resin in the presence of 1,1-dimethoxymethane, while its activity was as high as the activity of the fresh resin.

This experience shows that the addition of formaldehyde is especially effective in the case of a partially deactivated acidic ion-exchange resins.

Example 6

Liquid sample MMA containing CIS - and TRANS-2-methyl-2,4-hexadien and other impurities and 100 ppm GC, was passed through the fixed layer 16 g of the resin in the reactor of stainless steel with an outer diameter of 0.5 inch at atmospheric pressure and 70°C. the flow Rate was regulated to set the hold time to 31.7 minutes After the introduction of the source material, the samples were left at double the retention time, and then was collected and analyzed samples. Analysis of total concentration of CIS - and TRANS-2-methyl-2,4-dimethylhexane compared with the stream containing the raw MMA in table 16.

Table 16
Fresh resin
Start80 ppm HCHO200 ppm HCHO320 ppm HCHO
Source formalin
1,1-dimethoxymethane0,0061%0,0005%0,0005%0,0000%
37% formalin0,0061%0,0012%0,0000%0,0000%
The treated stream containing 81.5% of MeP, 10% HCHO, 6,5% methanol, 2% other substances0,0061%0,0007%0,0006%0,0000%
Used resin
Start80 ppm HCHO200 ppm HCHO320 ppm HCHO
Source formalin
1,1-dimethoxymethane0,0061%0,0018%0,0017%0,0000%
37% formalin0,0061%0,0026%to 0.0004%to 0.0004%
The treated stream containing 81.5% of MeP, 10% HCHO, 6,5% methanol, 2% other substances0,0061%0,0014%0,0015%0,0006%

This experience shows that there is no difference when adding formaldehyde in the form of 1,1-dimethoxymethane, formalin or stream of a solution of formaldehyde in anhydrous methanol.

Example 7

The layer containing 750 ml of acidic ion-exchange resin Lewatit 2431, used for handling contaminated MMA containing various impurities and 100 ppm of hydroquinone as stabilizer, at a flow rate of 600 g/h of the Flow supported within 62 days. Table 17 shows the data for the first 62-day period, the average concentration of various impurities (ppm) in the source and destination material and conversion agents for the source material containing at 17.5 ppm of formaldehyde.

Table 17
Source materialThe final materialConversion
Isobutyraldehyde96,137,461,1%
Methacrolein3,20,196,4%
Isobutanol50,727,745,3%
Pentenal8,90,297,4%
Toluene18,917,67,1%

Then, impurities were analyzed over a longer time maintain flow, as shown in table 18.

Table 18
Day 120-126Source materialThe final materialThe average conversion
Utilizare Edilkamin 2,70,0100,0%

For several branches of other components was required formaldehyde, when a resin used for an extended period of time. Figure 1 and table 19 show that for a complete separation of diphenylmethane (DCK) from the containing MMA requires more than 60 ppm of formaldehyde.

Table 19
The processing time of dayThe formaldehyde content, ppmThe share conversion diphenylmethane,
%
The processing time of dayThe formaldehyde content, ppmThe share conversion diphenylmethane,%
1153267%121204100%
1163272%121173100%
1163971%122 162100%
1174082%122143100%
1174467%123141100%
1184825%123144100%
1184859%124143100%
1195363%124153100%
119111100%125147100%
120200100%125152100%
120207100%126161100%

Example 8

Fresh ion-exchange resin (an aliquot (800 ml) was washed with methanol to separate the water at a flow rate of 0.15 g/ml/h to reduce the concentration of water is less than 0.2% wt. Then from the resin poured the excess methanol and washed her MMA at the same flow rate to reduce the methanol concentration below 0.2 wt.%. Double the amount used in the experience of contaminated MMA containing 111 h/million diethylketone and 320 ppm (formula-2 CH3-O-(CH2-O)2-CH3), (equivalent to the formaldehyde content of 180 ppm), then passed through the resin at a flow rate of 2 ml/min to displace pure MMA desirable component. The resin was transferred into a vessel and fill it with sample contaminated MMA, then through the sample was barbotirovany air through the cannula to its saturation. The vessel was sealed and then placed in an oil bath at 55°C. Periodically, samples were taken for analysis. The results of the analysis are shown in table 20.

Table 20
The processing time of the resin, hThe concentration of diethylketone, h/million
0,0/td> 111
0,7103,5
2,5102,5
the 3.895
4,891
5,8110
6,370
8,066
9,555
11,731
14,7537
15,538

Obviously, the method according to the present invention leads to a significant reduction of the content of diethylketone.

Attention is drawn to all materials and documents submitted at the same time or to the description in connection with the present application and which are open to public inspection with this description, and content of all these documents is included in the present invention by reference.

All the characteristics described in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any is shown in its method or process can be combined in any combination, except combinations where at least some of these features and/or steps are mutually exclusive.

Each feature described in this specification (including any accompanying claims, abstract and drawings), can be replaced by alternative features serving the same, equivalent or similar purpose, unless otherwise specified in a particular way. So, unless otherwise specified in a particular way, each given characteristic is only an example of the specific range of equivalent or similar features.

The present invention is not limited to the description of the above variants of its implementation. The present invention applies to any update or any new combination of traits listed in this specification (including any accompanying claims, abstract and drawings), or any update or any new combination of steps of any of these methods or processes.

1. The method of purification of methyl methacrylate (MMA), including the implementation of the contact containing liquid impurities MMA sulfoxylates resin in the presence of formaldehyde or a suitable source of methylene or ethylene of the formula I, as defined below:

where R5and R6independently selected from a hydrocarbon, C1 -C12or N;
X represents O;
n is an integer from 1 to 100; and
m has a value of 1 or 2.

2. The method of purification of methyl methacrylate (MMA) according to claim 1 in which the compound of formula I is a suitable source of formaldehyde.

3. The method of purifying methyl methacrylate according to claim 2, in which a suitable source of formaldehyde selected from 1,1-dimethoxymethane, the highest formula CH3-O-(CH2-Oh)i-CH3where i=2 or more, formalin or mixtures containing formaldehyde, methanol and methylpropionate.

4. The method of purifying methyl methacrylate according to claim 2, in which formaldehyde or its source is mixed with the contaminated liquid MMA before contact with sulfoxylates resin.

5. The method of purifying methyl methacrylate according to claim 2, in which the source of formaldehyde alternative or additionally be present as an impurity in MMA.

6. The method of purifying methyl methacrylate according to claim 3, in which formaldehyde or its source is mixed with the contaminated liquid MMA before contact with sulfoxylates resin.

7. The method of purifying methyl methacrylate according to claim 3, in which the source of formaldehyde alternative or additionally be present as an impurity in MMA.

8. The method of purifying methyl methacrylate according to claim 3, in which the impurity in MMA is pointless-2 (CH3-O-(CH2-Oh)2-CH3).

9. The method of purification of methyl methacrylate on any ISP-8, in which the formaldehyde or the amount of formaldehyde that can be distinguished from a suitable source of formaldehyde is present in a concentration of 0.01 to 0.1 wt.% relative to the mass of liquid MMA.

10. The method of purifying methyl methacrylate according to claim 9, in which the cleaning process of the present invention is carried out at a temperature of from 25 to 100°C.

11. The method of purifying methyl methacrylate according to claim 10, in which the temperature difference between the boiling impurities and MMA does not exceed 15°C.

12. The method of purifying methyl methacrylate according to claim 11, in which the impurities are selected from Isobutyraldehyde, taken either in pure form or as compounds that produce it when exposed sulfoxylates ion-exchange resin, optionally substituted of trienol6-C20, optionally substituted unsaturated aldehydes and ketones, diphenylmethane, ethylvanillin, diethylketone, ethylisopropylamine, 3-methylene-1-HEXEN-4-it, methacrolein, Isobutanol, toluene and penttala, for example 3-pentenal.

13. The method of purification of methyl methacrylate indicated in paragraph 12, in which the method is carried out in the presence of at least one suitable stabilizer.

14. The method of purifying methyl methacrylate according to item 13, in which the cleaning process is also present at least one ester of carboxylic acid.

15. The method of purifying methyl methacrylate according to claim 4 or 6, which are subject to yunam or semi-continuous process, the flow of contaminated liquid MMA is mixed with the stream, containing formaldehyde or its source, with the formation of the mixed liquid stream prior to contact with sulfoxylates resin.

16. The method of purifying methyl methacrylate according to claim 7, in which the combined liquid stream contains formaldehyde in an amount of 0.01-0.1 wt.%.

17. The method of purification of methyl methacrylate at 14, which in a continuous or semi-continuous process, at least one ester of carboxylic acid is already present in the stream of contaminated liquid MMA before contact with sulfoxylates resin.

18. The method of purification of methyl methacrylate (MMA), including the implementation of the contact containing liquid impurities MMA sulfoxylates resin in the presence of formaldehyde or a suitable source of methylene or ethylene of the formula I, as defined below:

where R5and R6independently selected from a hydrocarbon, C1-C12or N;
X represents O;
n is an integer from 1 to 100; and
m is 1 or 2; in which sulfonylurea resin at least partially deactivated.



 

Same patents:

FIELD: chemistry.

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20 cl, 8 ex

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15 cl, 4 ex

FIELD: chemistry.

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FIELD: chemistry.

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FIELD: chemistry.

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FIELD: chemistry.

SUBSTANCE: invention relates to improved methods of producing alkyl esters of methacrylic acid as a reaction product, particularly to a method in which a) a reaction mixture which contains an amide of methacrylic acid, water, sulphuric acid and at least one alkanol undergoes esterification in one or more reaction spaces, b) the crude reaction product, in at least one fractionation column, is subjected to a separation process to obtain a reaction product which contains water, alkyl methacrylate and alkanol, c) the reaction product obtained at step b) is condensed in one or more heat-exchangers, d) the condensate is separated in at least one separation device into an organic phase and an aqueous phase, e) the organic phase is washed with water to obtain a washed organic phased and flush water and f) the separated aqueous phase, along with the flush water, is returned to at least one reaction space. The invention also relates to an apparatus for producing alkyl esters of methacrylic acid, at least having i) one or more reaction spaces in which a reaction mixture, which contains an amide of methacrylic acid, water, sulphuric acid and alkanol, undergoes esterification, ii) at least one fractionation column in which the reaction product is subjected to separation, iii) one or more heat-exchangers in which the reaction product subjected to separation is condensed, iv) at least one separation device in which the condensate is separated into an organic phase and an aqueous phase, v) at least one washing column in which the organic phase is washed with water, vi) at least one liquid-conducting connection between the separation device and at least one reaction space, through which the separated aqueous phase, optionally along with flush water, is returned to at least one reaction space.

EFFECT: high efficiency.

18 cl, 11 dwg

FIELD: chemistry.

SUBSTANCE: in the method of neutralising acidic impurities during synthesis of acrylates, the neutralising agent used is ammonia solution with concentration of not less than 0.01% in amount which ensures pH of the mixture of 5.5-6.7, said mixture being formed after mixing the neutralising agent with raw acrylate. Said method involves preparation of a neutralising agent, mixing the prepared neutralising agent and raw acrylate followed by phase separation of the mixture into a top organic layer of raw acrylate and a bottom aqueous layer of spent neutralising agent. Copper sulphate is also added to the ammonia solution in amount of 0.6-0.12 wt %. When preparing the neutralising agent, the solution is mixed through circulation thereof. Ammonia solution concentration of 1-2% if optimum for industrial engineering. The apparatus has containers connected by pipes for preparing aqueous solution for the neutralising agent, a circulation pump, an overhead tank, a pump, a mixer, a phase separator, as well as an overhead tank for raw acrylate connected with the pump. The apparatus also has a container for ammonia solution and an additional pump fitted at the inlet of the container for preparing ammonia solution, and a pH metre fitted at the outlet of the mixer, where the mixer is in form of a turbulator. The turbulator is a metal pipe into which a disc with holes is fitted perpendicular the longitudinal axis, said disc being made from fluoroplastic or steel.

EFFECT: obtaining a high-purity end product, characterised by low content of acidic impurities, achieved owing to use of structural components and process operations which enable addition of a neutralising agent according to a defined scheme.

5 cl, 2 dwg, 1 tbl, 12 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of reducing concentration of aldehyde in the crude stream of a carbonylation process, involving feeding a crude stream containing a carbonylatable agent selected from a group consisting of methanol, methyl acetate, methyl formate and dimethyl ether or mixture thereof, having primary concentration of aldehydes; and reaction thereof in gaseous phase with a deposited catalyst which contains at least one metal from group 8 to 11, in conditions which facilitate reduction of primary concentration of aldehydes to secondary concentration of aldehydes.

EFFECT: method improves degree of reduction of aldehyde.

28 cl, 3 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention refers to advanced process of diacerein production with aloe-emodin and it mono-, di - and triacetylate derivatives within 0 to 5 parts per million containing water-organic solution of weak-base diacerein salt is extracted with solvent miscible or practically immiscible with water. Method allows for product containing diacerein and up to 5 parts per million of aloe-emodin, i.e. enables product with low aloe-emodin content, and is characterised with simplicity of implementation.

EFFECT: product with low aloe-emodin content and simplicity of implementation.

10 cl, 6 ex

FIELD: industrial organic synthesis.

SUBSTANCE: method comprises contacting vapor-phase mixture at 150-205°C with alkali and/or alkali-earth metal carboxylate dispersed on activated carbon resulting in conversion of alkyl iodides into corresponding carboxylic acid esters, while iodine becomes bound in the form of inorganic iodide.

EFFECT: facilitated freeing of carboxylic acid product from organic iodine compounds.

4 cl, 2 tbl, 32 ex

The invention relates to methods for complex diesters of terephthalic acid and diodes of polyesters

FIELD: chemistry.

SUBSTANCE: invention relates to field of catalyst. Described is method of obtaining silver crystals with distribution of average size of particles from 0.15 mm to 2.5 mm and porous coating of oxide materials in which a) silver crystals contact with sol-gel solution of said materials, in solvent, which contains organic solvent and b) obtained as a result silver crystals are collected, c) released from organic solvent and d) then subjected to thermal processing at temperature between 50°C and point of silver melting. Described is application of obtained crystals as catalyst for obtaining formaldehyde.

EFFECT: increased activity of catalyst for obtaining formaldehyde.

10 cl, 3 dwg, 4 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method for direct conversion of lower C1-C4 paraffins to oxygenates such as alcohols and aldehydes, which are valuable intermediate products of organic synthesis and can be used as components of engine fuel and/or starting material for producing synthetic gasoline and other engine fuels. The method involves passing a mixture consisting of a lower paraffin or oxygen, diluted with an inert gas or air or pure oxygen, through a catalyst bed at temperature not higher than 350°C. The catalyst used is a catalyst system for heterogeneous reactions, which contains microfibre of a high-silica support and at least one active element, the active element being in form of either a MeOxHalv composite or a EwMezOxHaly composite, wherein the element Me in both composites is selected from a group which includes transition metals of groups 5-12 and periods 4 and 5, or elements of lanthanum or lanthanide groups or, preferably, ruthenium; element Hal is one of the halogens: fluorine, chlorine, bromine, iodine, but preferably chlorine; element E in the EwMezOxHaly composite is selected from a group which includes alkali, alkali-earth elements, or hydrogen, and indices w, z, x and y are weight fractions of elements in given composites and can vary in the following ranges: z - from 0.12 to 0.80, x - from 0.013 to 0.34, y - from 0.14 to 0.74, w - from 0 to 0.50.

EFFECT: method enables to achieve high degree of conversion of starting reactants and high selectivity of formation of alcohols.

4 cl, 15 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method for direct conversion of lower C1-C4 paraffins to oxygenates such as alcohols and aldehydes, which are valuable intermediate products of organic synthesis and can be used as components of engine fuel and/or starting material for producing synthetic gasoline and other engine fuels. The method involves passing a mixture consisting of a lower paraffin or oxygen, diluted with an inert gas or air or pure oxygen, through a catalyst bed at temperature not higher than 350°C. The catalyst used is a catalyst system for heterogeneous reactions, which contains microfibre of a high-silica support and at least one active element, the active element being in form of either a MeOxHalv composite or a EwMezOxHaly composite, wherein the element Me in both composites is selected from a group which includes transition metals of groups 5-12 and periods 4 and 5, or elements of lanthanum or lanthanide groups or, preferably, ruthenium; element Hal is one of the halogens: fluorine, chlorine, bromine, iodine, but preferably chlorine; element E in the EwMezOxHaly composite is selected from a group which includes alkali, alkali-earth elements, or hydrogen, and indices w, z, x and y are weight fractions of elements in given composites and can vary in the following ranges: z - from 0.12 to 0.80, x - from 0.013 to 0.34, y - from 0.14 to 0.74, w - from 0 to 0.50.

EFFECT: method enables to achieve high degree of conversion of starting reactants and high selectivity of formation of alcohols.

4 cl, 15 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing a catalyst for oxidising methanol to formaldehyde and can be used in production of formaldehyde and urea-formaldehyde resin. The method of producing a catalyst for oxidising methanol to formaldehyde involves reaction of an iron-containing component with molybdenum trioxide with subsequent moulding of granules, drying and calcination, wherein the iron-containing component used is iron oxide, and the reaction is carried out in a mill with impact-shear action and power density 10-200 W/g and weight ratio MoO3:Fe2O3=(80-40):(20-60).

EFFECT: use of the invention increases specific surface area by 51-84%, mechanical strength by 60-68%, and cuts the number of process operations twofold.

1 cl, 1 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of decomposing high-boiling by-products of production of isoprene from isobutylene and formaldehyde by mixing high-boiling by-products with superheated water vapour and contact with a catalyst in one or two deck-type reactors while heating to obtain isoprene, formaldehyde and isobutylene, characterised by that liquid high-boiling by-products are first evaporated and superheated to temperature 300-350°C together with water vapour in ratio 1:1.0-1.2 in the convection part of a vapour-superheating furnace in a system of straight pipes fitted with a self-contained collector, and then mixed in a mixer with superheated water vapour to weight ratio 1:3.0-4.0, and then fed at 400-450°C into a reactor, in the over-catalyst zone of which there is a clearing-distribution grid with common clear area of 15%, having 20 mm holes and caps with diameter of 100 mm and height of 80 mm.

EFFECT: use of the present method enables to loser specific consumption of water vapour when splitting high-boiling by-products with simultaneous increase in output of desired products.

2 cl, 3 ex, 1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to a method for homogeneous oxidation of a methane-containing gas, involving feeding into the cycle a methane-containing gas preheated to 430-450°C in at least three series-arranged oxidation reactors made from carbon steel. Each of the reactors, except the last, is separately connected to exhaust-heat boilers. Oxygen is also fed into the reactors in such an amount that a mixture forms outside the explosive range, which causes homogeneous oxidation of the methane-containing gas while simultaneously raising temperature of the gas mixture to 540-560°C. Subsequent quenching-cooling of the gas mixture is carried out in exhaust-heat boilers to temperature 440-450°C by feeding water into the exhaust-heat boilers where vapour is formed, which is fed into fractionation columns for separating end products. Further, the reaction mixture from the last reactor which is not connected to an exhaust-heat boiler enters a separator. On he way to the separator, the reaction mixture heats the gas and some of its heat is used to obtain water vapour, which is mixed with vapour from the heat-exchange boilers. From the separator, the liquid phase enters the fractionation step where methanol rectificate is obtained, as well as ethyl alcohol and formaldehyde. The gaseous phase goes absorbers for removal of SO2, CO and CO2. In the first absorber, the gaseous phase is purified from SO2 and from CO and CO2 in the second absorber, followed by extraction of said gases from the absorption solution of the second absorber in a desorber. Liquid phase outlets of the absorbers are connected to collectors to facilitate reclamation of absorbing solutions with separation and outlet of CO and CO2 fractions from the desorber. Outlets of the collectors are connected to inlets of the absorbers for feeding the formed solutions for removing SO2, CO and CO2 from the gas. While cleaning the gas phase, the circulation cycle is partially blown in order to remove inert gases, for example nitrogen and argon entering the cycle together with the methane-containing gas and oxygen. The number of blows is determined by the amount of inert gases available in the cycle. After purification and blowing, the cycle is closed by injecting the gaseous phase which consists of methane-containing gas and gas from the second absorber. The invention also relates to apparatus for homogeneous oxidation of methane-containing material.

EFFECT: high efficiency during operation and high output of the obtained product, as well as high environmental friendliness.

2 cl, 1 tbl, 1 dwg

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