Carboxylic acid synthesis method

FIELD: chemistry.

SUBSTANCE: invention relates to a carboxylic acid synthesis method. The invention specifically relates to a method for synthesis of carboxylic acids through oxidation of a hydrocarbon with oxygen or an oxygen-containing gas, and more specifically to oxidation of cyclohexane to adipinic acid. According to the invention, the method involves a step for oxidising the hydrocarbon and at least one step for extracting the formed dicarboxylic acids from the reaction medium and, in known cases, return unconverted hydrocarbon and oxidation by-products such as ketones and alcohols which may be formed to the reaction. The disclosed method also includes a step for conversion, separation or extraction of α,ω-hydroxycarboxylic compounds formed during oxidation. This step for conversion, separation or extraction of α,ω-hydroxycarboxylic compounds involves oxidation of medium containing the said compounds in order to convert them to dibasic acids.

EFFECT: design of an efficient method of obtaining carboxylic acids.

16 cl, 10 ex

 

Description

The present invention relates to a method of producing carboxylic acids.

More specifically, it concerns a method of producing carboxylic acids by oxidation of a hydrocarbon with oxygen or gas containing oxygen, and, more specifically, the oxidation of cyclohexane to adipic acid.

Adipic acid is an important chemical compound used in many areas. So, adipic acid can be used as an additive in many products, both in food and in the field of concrete. However, one of the most important applications is its use as a monomer in obtaining polymers, including polyurethanes and polyamides.

Have been proposed several methods for producing adipic acid. One of the most important used in large industrial scale, is oxidation, in one stage or in two stages, of cyclohexane to a mixture of cyclohexanol/cyclohexanone gas containing oxygen, or oxygen. After extraction and purification of a mixture of cyclohexanol/cyclohexanone these compounds are oxidized, in particular, adipic acid and nitric acid.

However, this method has a great disadvantage associated with the formation of a pair containing the oxides of nitrogen.

Numerous studies have been conducted for th is would be to develop a method of oxidation of hydrocarbons with oxygen or a gas, containing oxygen, which allows to directly obtain carboxylic acids, especially adipic acid.

The above methods are described in particular in patents FR 2761984, FR 2791667, FR 2765930, US 5294739.

Usually the reaction is carried out in the environment of the solvent, while the solvent is a monocarboxylic acid such as acetic acid. Were offered other solvents, such as carboxylic acid having a lipophilic character, described in the patent FR 2806079.

Numerous patents describe the conditions for this reaction, as well as various extraction stages formed acids, cleaning them and, equally, recirculation of oxygenated hydrocarbons, as well as a catalyst.

However, this oxidation reaction produces by-products that can be more or less obvious way to reduce the output of the process. Among the above-mentioned by-products, some, such as alcohols, react with the formed acids to form esters, which must be removed from the reaction medium in order to avoid their accumulation or formation of impurities, undesirable and difficult to separate from acids formed.

Other intermediate oxidation products, such as α,ω-hydroxycarbazole compounds are undesirable if they are not removed from the reaction mixture or not transformer who are. In fact, these compounds are often difficult separable from dibasic acids, making it difficult to obtain pure dibasic acid, in particular with the degree of purity required for use as a monomer in obtaining polyamides.

For the economy of the process and, equally, to obtain a dibasic acid of high purity, it is important to reduce the concentration of by-products in the reaction medium and, in particular, allocated dibasic acids.

One of the purposes of the present invention is to provide a method of obtaining a dibasic acids, allowing to delete, remove or transform the by-products formed in the oxidation reaction.

To this end, the invention proposes a method of obtaining a dibasic carboxylic acids by oxidation of cycloaliphatic hydrocarbon with molecular oxygen or a gas containing molecular oxygen, in the presence of a solvent.

According to the invention the method includes a stage of oxidation of the hydrocarbon and at least one stage of extraction of the resulting dicarboxylic acids from the reaction medium and, if necessary, recycling nontransgenic hydrocarbon and by-products of oxidation, such as alcohols and ketones, which may be formed.

The method is according to the invention also contains a stage of transformation, removal or extraction of α,ω-hydroxycarbazole compounds formed during the oxidation steps.

Mentioned phase transformation, removal or extraction of α,ω-hydroxycarbazole compounds is that the media containing the indicated compounds, is subjected to oxidation in order to turn them into a dibasic acid. The oxidation reaction is carried out, in certain cases, in the presence of a catalyst containing a catalytically active metal element or compound of the metal selected from the group consisting of Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Sc, In, Tl, Y, Ga, Ti, Zr, Hf, Ge, Sn, Pb, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, lanthanides, such as Ce, and combinations of these elements, preferably, precious metals such as platinum, gold, silver, ruthenium, rhenium, palladium, or mixtures thereof. Favorably, this catalytically active metal or a catalytically active compound of the metal is deposited, impregnated or grafted on porous media, such as the gas carbon black, alumina, zeolites, silicon dioxide, graphite and in a more General view of the media used in the field of catalysis.

The preferred catalyst according to the invention is, in particular, the catalyst, the platinum containing compound deposited on the gas soot.

The oxidation reaction of α,ω-hydroxycarbonate the compounds is carried out, preferably, at a temperature in the range from 50 to 150°C.

The oxidant suitable for this stage is molecular oxygen or gas containing molecular oxygen. Similarly, it is possible to use other oxidizing agents such as hydrogen peroxide, ozone, nitric acid.

According to the first method embodiment of the invention stage of transformation, delete or extract hydroxycarbonate compounds is carried out in the environment, leaving the oxidation reactor, before separating the resulting dibasic acids and unreacted hydrocarbon, i.e. in the presence of the organic phase.

According to the second method embodiment of the invention stage of transformation hydroxycarbonate compounds is carried out in a medium containing the resulting dibasic acid, after removing dibasic acids from the reaction medium oxidation, or after crystallization dibasic acids, the mother solution crystallization, i.e. on the medium formed by the aqueous phase.

Thus, in the first mode for carrying out the invention a homogeneous or heterogeneous oxidation catalyst added to the reaction medium either in the oxidation reactor after completion of the oxidation reaction of the hydrocarbon, or in one or more different oxidation reactors, which serves the reactions is nnow environment. In this way the implementation of the used catalyst is, preferably, a homogeneous metal catalyst or a mixture of homogeneous catalysts. Temperature is defined and, for example, is in the range from 50 to 150°C.

The oxidant preferably is oxygen or a gas containing oxygen, as air, for example. In this case, the oxygen partial pressure is preferably from 0.1 to 30 bar.

In the second mode for carrying out the invention, the oxidation of α,ω-hydroxycarbazole compounds is carried out in aqueous medium or in the absence of catalyst or in the presence of a catalyst, such as defined below. Preferably, the catalyst is a heterogeneous catalyst and oxidising agent is, for example, oxygen gas containing oxygen, nitric acid, hydrogen peroxide, ozone.

The method according to the invention applies, in particular, the oxidation of cyclohexane to adipic acid production. Similarly, it can be used in the oxidation of other hydrocarbons, such as cyclododecane.

The oxidation reaction of a hydrocarbon, such as cyclohexane, is usually carried out in the presence of a solvent. This solvent can be of different nature in so far as he is neocaledonica under reaction conditions. In h is particularly it can be selected among proton polar solvents and polar aprotic solvents. As proton polar solvents include, for example, carboxylic acids, containing only primary or secondary hydrogen atoms, in particular aliphatic acid containing from 2 to 9 carbon atoms, such as acetic acid, performancebuy acid, such as triperoxonane acid, alcohols, such astert-butanol, halogenated hydrocarbons such as dichloromethane, ketones, such as acetone. As polar aprotic solvents include, for example, complex lower alkalemia esters (= alkyl radical containing from 1 to 4 carbon atoms) carboxylic acids, in particular aliphatic carboxylic acids containing from 2 to 9 carbon atoms, or performancebuy acids, tetramethylarsonium (or sulfolan), acetonitrile or benzonitrile.

Similarly, the solvent can be selected from among carboxylic acids with lipophilic character.

Under the lipophilic compound of acidic character, suitable for the invention involve aromatic, aliphatic, arylaliphatic or alkylaromatic compound of acidic character containing at least 6 carbon atoms, which may contain several functional GRU is p acidic in nature and have low solubility in water, that is, the solubility is less than 10 wt.% at room temperature (10°C - 30°C).

As lipophilic organic compounds include, for example, nylon, heptane, octane, 2-ethylcaproic, pelargonium, capric, undecanoyl, lauric, stearic (octadecanoic) acids and their permitieron derivatives (complete substitution of the hydrogen atoms of methylene groups, methyl group), 2-octadecylamino, 3,5-distritbution, 4-tertbutylbenzene, 4-octylbenzoic acid, hydrogenated tertbutylether, naphthenic or anthracene acid, substituted alkyl groups, preferably of the type tertiary butyl, substituted derivatives of phthalic acid, dibasic fatty acids, such as dimer fatty acids. Similarly, you can call acid belonging to the previous collections and bearing various electron-donating substituents (groups with heteroatoms type O or N) or electron-withdrawing substituents (halogen, sulfonamide, nitro-, sulfonate or similar groups). Preferred are a substituted aromatic acid.

Typically, the solvent is chosen in such a way as to obtain, preferably, a homogeneous phase under conditions of temperature and pressure at which the oxidation reaction. This is beneficial to the solubility of the solvent in the carbohydrate of the kind or in the reaction medium would be, at least 2 wt.% and so was formed of at least one homogeneous liquid phase containing at least a portion of the oxidizable hydrocarbons and part of the solvent.

Preferably, the solvent is chosen among those solvents that are soluble in water, i.e. which have a solubility in water less than 10 wt.% at room temperature (10°C - 30°C).

Nevertheless, without going beyond the scope of the invention, it is possible to use a solvent having a solubility in water greater solubility indicated before, if the distribution coefficient of the connection between the organic phase or the organic phase of the reaction medium formed essentially of oxidized hydrocarbon, intermediate oxidation products and the inorganic phase containing water formed during the oxidation reaction, allows the concentration of solvent in the above-mentioned aqueous phase is less than 10 wt.%.

Typically the oxidation is carried out in the presence of a catalyst. This catalyst contains, preferably, a metal element selected from the group containing Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Sc, In, Tl, Y, Ga, Ti, Zr, Hf, Ge, Sn, Pb, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, lanthanides, such as Ce, and the combination of these elements.

These catalytic elements are used either in the form of compounds, predpochtitelno, at least partially soluble in the liquid medium oxidation conditions of the oxidation reaction, or applied, absorbed, or related to, inert carrier such as, for example, silicon dioxide, aluminum oxide.

Preferably, the catalyst is, in particular, the conditions of the oxidation reaction:

any soluble oxidizable hydrocarbon,

any soluble in the solvent,

any soluble in the mixture of the hydrocarbon/solvent forming conditions of the reaction homogeneous liquid phase.

According to a preferred method of carrying out the invention is used, the catalyst is soluble in one of these environments at room temperature or at a temperature of recyclization listed environments in new oxidation.

The term “soluble” means that the catalyst is at least partially soluble in the environment.

In the case of a heterogeneous catalyst catalytically active metal elements deposited or embedded in micro - or mesoporous inorganic matrix or a polymer matrix, or are in the form of an ORGANOMETALLIC complex compounds grafted on organic or mineral media. The term “embedded” means that the metal is an element wear is El, or work with complex compounds, sterically trapped in porous structures under oxidizing conditions.

In a preferred method of carrying out the invention a homogeneous or heterogeneous catalyst composed of salts or complex compounds of metals of the IVb (Ti group), Vb (group V), VIb (Cr group), VIIb (group Mn), VIII (Fe, or Co, or Ni), Ib (group Cu) groups and cerium, taken individually or in a mixture. The preferred elements are, in particular, Mn and/or Co in combination with one or more other metal elements, such as Zr, Hf, Ce, Fe.

The concentration of the metal in a liquid medium oxidation range from 0.00001 to 5% (wt.%), preferably, from 0.001% to 2%.

On the other hand, the concentration of solvent in the reaction medium is defined, it is preferable, therefore, to have a molar ratio between the number of solvent molecules and the number of atoms of the catalytic metal in the range from 0.5 to 100,000, preferably from 1 to 5000.

Concentration of the solvent in a liquid medium oxidation may vary within wide limits. So, it can be in the range from 1 to 99 wt.% in relation to the total weight of liquid medium, more preferably, it may be in the range of from 2 to 50 wt.% from the liquid environment.

Similarly, you can, without leaving the scope of the invention, to use the solvent in combination with another compound, adding which may, in particular, have the consequence of improving productivity and/or selectivity of the oxidation reaction in adipic acid and, in particular, the dissolution of oxygen.

As examples of the above compounds include, in particular, NITRILES, hydroxyamine compounds, halogenated compounds, more preferably, fluorine-containing compounds. As more particularly suitable compounds can be called NITRILES, such as acetonitrile, benzonitrile, imides, belonging to the family described in the patent application EP 0824962, and more specifically, N-hydroxysuccinimide (N-HS) (NHS) or N-hydroxyphthalimide (N-GFI) (NHPI), halogenated derivatives, as dichloromethane, fluorine-containing compounds, such as:

- aliphatic hydrocarbons, fluorinated or perfluorinated cyclic or acyclic;

- fluorine-containing aromatic hydrocarbons such as perpertual, performatilicious, performante, perfluorooctane, pertemanan, perpendicular, performatively, α,α,α-triptorelin, 1,3-bis(trifluoromethyl)benzene;

- perfluorinated or fluorinated esters, such as alkylphenolate, alkylphosphonate;

fluorinated or perfluorinated ketones, such as perforation;

fluorinated or perfluorinated alcohols, such as the perfluorinated hexanol, the octanol nonanol, decanol, perfluorinatedtert-butanol, perfluorinated-propanol, 1,1,1,3,3,3-geksaftorpropena-2;

fluorinated or perfluorinated NITRILES, such as perfluorinated acetonitrile;

fluorinated or perfluorinated acids such as triftorperasin acid, pentafluorobenzoic acid, perfluorinated nylon, heptane, octane, pelargonia acid, perfluorinated adipic acid;

fluorinated or perfluorinated halides, such as perfluorinated iodooctane, perfluorinated Brookton;

fluorinated or perfluorinated amines, such as perfluorinated Tripropylamine, perfluorinated tributylamine, perfluorinated triphenylamine.

More specifically, the invention is applied in the oxidation of cycloaliphatic compounds, such as cyclohexane, cyclododecane into the corresponding linear dibasic acid, adipic acid, dodecandioic.

According to a preferred method of carrying out the invention it relates to a direct oxidation of cyclohexane to adipic acid with oxygen or gas containing oxygen, in a liquid medium and in the presence of a catalyst based on manganese, or a combination of manganese/cobalt.

The oxidation reaction is carried out at a temperature in the range from 50°C to 200°C,preferably from 70°C to 180°C. the Reaction can be carried out at atmospheric pressure. However, it is usually carried out under pressure in order to maintain the components of the reaction medium in liquid form. The pressure may range from 10 kPa (0.1 bar) to 20,000 kPa (200 bar), preferably from 100 kPa (1 bar) to 10,000 kPa (100 bar).

Used oxygen may be in pure form or in mixture with an inert gas such as nitrogen or helium. Similarly, you can use the air, more or less enriched with oxygen. The amount of oxygen supplied to the medium is, preferably, from 1 to 1000 moles per mole of oxidized compounds.

The method of oxidation can be carried out continuously or periodically. Preferably, the liquid reaction medium leaving the reactor, treated according to known methods, allowing, on the one hand, to separate and extract the resulting dibasic acid and, on the other hand, to return to the reactor unoxidized or partially oxidized organic compounds, such as cyclohexane, cyclohexanol and/or cyclohexanone. Similarly, it is advantageous to use a connection that initiates the oxidation reaction, such as, for example, ketone, alcohol, aldehyde or a hydroperoxide. Clearly indicate cyclohexanone, cyclohexanol and the hydroperoxide of cyclohexyl, which are R actionresponse intermediate products in the case of oxidation of cyclohexane. Usually the initiator is from 0.01% to 20 wt.% from the mass used in the reaction mixture, without the above content was critical. The initiator always used at the beginning of the oxidation. It can be entered since the beginning of the reaction.

Similarly, the oxidation can be carried out in the presence of water introduced at the initial stage of the process.

As indicated above, the reaction mixture resulting from the oxidation is subjected to different allocations of some of its components, for example, in order to make it possible for them to return to the level of oxidation and extraction of the formed acid.

According to the first method embodiment of the invention the environment, leaving the oxidation reactor, directly subjected to the second stage of oxidation in the presence of a homogeneous or heterogeneous metal catalyst. Conditions of temperature and pressure may be similar or different from the conditions used at the stage of oxidation of the hydrocarbon. Used the oxidant may be oxygen, a gas containing oxygen, hydrogen peroxide, ozone, an organic hydroperoxide or a similar connection, for example. At this stage of the oxidation, the resulting α,ω-hydroxycarbonate connection, such as gidroksicarbonata acid, in the case of oxidation of cyclohexane, the pre is rasaut in the dicarboxylic acid. As stated before, this stage are carried out either in the oxidation reactor, or in one or more reactors.

The catalyst is preferably a homogeneous catalyst formed of at least one compound of a metal selected from the group containing Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Sc, In, Tl, Y, Ga, Ti, Zr, Hf, Ge, Sn, Pb, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, lanthanides, such as Ce, and combinations of these elements.

Similarly, you can use a heterogeneous catalyst containing as catalytic phase one of the metal compounds mentioned above.

The output from this stage the reaction mixture is cooled and decanted from the at least two liquid phases: one or more of the organic phase containing essentially unreacted hydrocarbon, in certain cases, the solvent and some of the intermediate oxidation products such as alcohols and ketones, and the aqueous phase containing dibasic acids formed during the oxidation of hydrocarbons and during the phase transformation of α,ω-hydroxycarbonate connections.

Preferably, the organic phase is washed several times with water or an acidic aqueous solution in order to allocate the maximum amount of dibasic carboxylic acids.

The organic phase, which contains okislennye hydrocarbon (cyclohexane), and some of the intermediate oxidation, such as cyclohexanone, cyclohexanol, return, preferably, to the stage of oxidation of the hydrocarbon.

When the acid solvent is a solvent having a lipophilic character, the solvent is present in the organic phase, as it is insoluble in water. So his return to the stage of oxidation with unoxidized cyclohexane. This return of the solvent occurs, particularly when the solvent is selected from among a substituted or unsubstituted aromatic acids, such astert-butylbenzoic acid. The resulting dibasic acids, in particular adipic acid, allocate, based on the aqueous phase, for example, by recrystallization.

Underlined acid cleaned, preferably, according to conventional methods described in numerous documents. Among the ways of purification purification by recrystallization from various solvents such as water, an aqueous solution of acetic acid, alcohols, is preferred. The cleaning methods described in particular in French patents No. 2749299 and 2749300.

Also, if the catalyst for the oxidation of hydrocarbon is not returned completely to the organic phase and partially or completely removed with the aqueous phase, preferably, it will be extracted from aqueous F. the SHL different methods, for example, such as liquid-phase extraction, electrodialysis, processing of ion-exchange resins.

In the second method of the invention, the phase oxidation of α,ω-hydroxycarbazole compounds such as 6-gidroksicarbonata acid, carried out on the aqueous phase, selected after stage cooling and decanting the reaction medium oxidation and/or aqueous phase, obtained by washing the organic phase, and the mother solution, highlighted by crystallization dicarboxylic acid.

In the above-mentioned second method of performing the oxidation of α,ω-hydroxycarbazole compounds is carried out in the presence or in the absence of a catalyst, oxygen or gas containing oxygen, as air, for example. You can also use other oxidizing agents such as nitric acid, hydrogen peroxide, ozone. The oxidation reaction is carried out at a temperature in the range from 50°C to 150°C and at pressure of oxygen in the range from 0.1 to 30 bar of oxygen partial pressure.

Preferably, the used catalyst is a heterogeneous catalyst, for example, applied catalyst containing as the catalytically active metallic substance, compound or mixture of compounds of metallic elements selected from the group comprising Au, Pt, Ru, Cr, Ti, V, M, Fe, Co, Zn, Mo, Rh, Pd, Ag, W, Re, Os, and Bi. As the catalyst, particularly suitable for the invention include catalysts based on platinum deposited on charcoal, aluminum oxide, titanium oxide, or a catalyst based on platinum and bismuth deposited on charcoal.

This operation of the oxidation can be carried out on all water phases allocated during the extraction and purification of dicarboxylic acids, in particular, on the mother solution crystallization. Similarly, it can be carried out simultaneously with the separation by decantation of the aqueous phase and organic phase.

After oxidation of selected aquatic environment handle, as before, in order to extract dibasic acids, in particular adipic acid.

Preferably, the method according to the invention may contain phase hydrolysis of esters formed at the stage of oxidation. Mentioned stage hydrolysis described in the French patent 2846651, for example.

Favorably, and preferably, this stage of the hydrolysis is carried out in the organic phase, selected after stage cooling and decant/wash.

The method according to the invention allows to obtain a dibasic acid oxidation of cyclic hydrocarbons with oxygen or gas containing oxygen, with the management of oxygenated hydrocarbon, without accumulation of various poboc who's products formed at the stage of oxidation. In addition, selected dibasic acid or dedicated dibasic acid can be easily cleaned, as they are not contaminated with some of the byproducts of the oxidation reaction of the hydrocarbon.

Other advantages and details of the invention will appear more clearly when considering the examples given only as an illustration.

Example 1: comparative

Six hundred grams (600 g) of an aqueous solution obtained by separating the reaction medium obtained in the oxidation of cyclohexane with air in the presence oftert-butylbenzoic acid and catalyst based on manganese and cobalt, such as described in French patent No. 2828194 contain, in particular:

adipic acid: 30%

succinic acid: 2,35%

glutaric acid: the ceiling of 5.60%

6-gidroksicarbonata acid: 4,46%.

To obtain crystalline adipic acid, the resulting aqueous solution is cooled.

The solid is obtained by filtration, washed with water, then dissolve when heated in 300 ml of water.

The new solution is cooled to ensure the crystallization of adipic acid.

This operation is repeated once.

Hydroxypropranolol acid quantify in the resulting adipic acid after each crystallization:

1Icrystallization: 1986 ppm

2Icrystallization: 73 ppm

3Icrystallization: 22 h/million

This experiment shows that we need to do at least three successive crystallization of adipic acid in order to obtain a low concentration hydroxypropranolol acid adipic acid corresponding to the desired specifications.

Example 2: comparative

Five hundred and eighty grams (580 g) the reaction medium obtained in the oxidation of cyclohexane with air in the presence of tert-butylbenzoic acid and catalyst based on manganese and cobalt, such as described in French patent No. 2828194, washed with 250 ml of water to extract different compounds soluble in water, in particular the formed acid and 6-hydroxypropranolol acid.

The resulting aqueous phase contains, in particular 1 wt.% formic acid, 0.7 wt.% succinic acid, 3.4 wt.% glutaric acid, 7.3 wt.% adipic acid, 1.4 wt.% 6-hydroxypropranolol acid (Nocap) (Nasar). This aqueous phase, in the amount of 3.65 g, loaded into an autoclave, stirring to perform the agitation, in the presence of Pt deposited on powdered coal supplied to the sale by the company Engelhard (molar ratio Nocap/Pt = 15). The reaction proceeds at a pressure of 25 bar at 90°C for 3 days. According to chromatographic EN the Lisa experiment leads to the conversion of 6-hydroxypropranolol acid 100%, conversion of formic acid 100% and the actual yield of adipic acid 80% compared to introduced in the reaction of 6-hydroxypropranolol acid. The resulting mixture was treated with conventional methods of crystallization of adipic acid. Contents 6-hydroxypropranolol acid (Nocap) adipic acid after the first crystallization is less than 2 h/million

Example 3

Example 2 is repeated, but replacing at the stage of oxidation of 6-hydroxypropranolol acid air on H2About2and the platinum catalyst 13 mg of tungsten acid.

After heating at 20°C for 4 hours to 20.4% hydroxycitronellal acid converted into adipic acid.

Example 4

Example 2 is repeated, but replacing at the stage of oxidation of 6-hydroxypropranolol acid air in the nitric acid solution with a concentration of 60 wt.% and using as the catalyst a composition containing 6000 ppm, by weight based on copper, copper nitrate (Cu(NO3)2·NO), 300 ppm, based on vanadium, VO3NH4.

The reaction is carried out at 70°C for 3 hours. 6-gidroksicarbonata acid is completely transformed. The yield of adipic acid is 68% compared to introduced in the reaction of 6-hydroxypropranolol acid.

Example 5

Example 2 is repeated, but replacing the platinum catalyst on the coal at the palladium acetate added to conc is of 10 wt.%.

The degree of transformation of 6-hydroxypropranolol acid is 100%. The yield of adipic acid is 63% compared to introduced in the reaction of 6-hydroxypropranolol acid.

Example 6

Example 2 is repeated, but replacing the platinum catalyst at an angle on the applied catalyst formed by aluminum oxide as a carrier, and a combination of Ag/Pd, as applied catalytic phase in which the concentration of the catalytic phase, expressed in terms of the mass of metal is 10 wt.% in relation to the media on the basis of aluminum oxide.

The degree of transformation of 6-hydroxypropranolol acid is 57%, and the yield of adipic acid is 59% compared to turned 6-hydroxypropranolol acid.

Example 7

Example 2 is repeated, but replacing the platinum catalyst at an angle on the applied catalyst formed activated carbon as a carrier, and a combination of Ru/Fe, as applied catalytic phase in which the concentration of the catalytic phase, expressed in terms of the mass of metal is 10 wt.% in relation to media-based activated carbon.

The degree of transformation of 6-hydroxypropranolol acid is 86%, and the yield of adipic acid is 46% compared to turned 6-hydroxypropranolol acid.

Example 8

Example 2 repeat Aut, but replacing the platinum catalyst on the corner of the damages of the catalyst formed by the graphite, as a carrier, and a combination of Pt/Bi, as applied catalytic phase in which the concentration of the catalytic phase, expressed in terms of the mass of metal is 10 wt.% with respect to graphite media.

The degree of transformation of 6-hydroxypropranolol acid is 96%, and the yield of adipic acid is 81% compared to turned 6-hydroxypropranolol acid.

Example 9

Example 2 is repeated, but replacing the platinum catalyst at an angle on the applied catalyst formed by aluminum oxide as a carrier, and a combination of Pt/Bi, as applied catalytic phase in which the concentration of the catalytic phase, expressed in terms of the mass of metal is 10 wt.% in relation to the media on the basis of aluminum oxide.

The degree of transformation of 6-hydroxypropranolol acid is 82%, and the yield of adipic acid is 69% compared to turned 6-hydroxypropranolol acid.

Example 10

Example 2 is repeated, but replacing the platinum catalyst at an angle on the applied catalyst formed by titanium oxide as a carrier, and platinum, as applied catalytic phase in which the concentration of the catalytic phase, expressed in the calculations of the e on the weight of the metal, is 10 wt.% in relation to the media on the basis of titanium oxide.

The degree of transformation of 6-hydroxypropranolol acid is 100%, and the yield of adipic acid is 69% compared to turned 6-hydroxypropranolol acid.

1. A method of obtaining a dibasic carboxylic acids by oxidation of cycloaliphatic hydrocarbon with oxygen or gas containing oxygen, in the presence of a solvent, which consists in effecting the oxidation of cycloaliphatic hydrocarbon, removing from the reaction medium formed dibasic acids liquid-phase extraction with water or an aqueous solution of acid as the extracting solvent, the allocation of the resulting dibasic acids by crystallization, based on the aqueous phase, the selected output liquid-phase extraction, recirculation of the organic phase, the selected output stage of oxidation, at the stage of oxidation, characterized in that it contains a phase transformation of α,ω-hydroxycarbazole compounds formed at the stage of oxidation, which consists in the oxidation of the above hydroxycarbonate compounds in dibasic acid.

2. The method according to claim 1, characterized in that it contains one or several stages of crystallization of dibasic acids in the aqueous phase.

3. The method according to claim 1 or 2, characterized in that the oxidation of hydroxycarbonic the x compounds is carried out in a reaction medium at the outlet of the oxidation reaction.

4. The method according to claim 3, characterized in that the oxidation of α,ω-hydroxycarbazole compounds is carried out by adding the catalyst in the reactor oxidation after oxidation of the hydrocarbon.

5. The method according to claim 3, characterized in that the oxidation of α,ω-hydroxycarbazole compounds is carried out in one or more additional reactors oxidation.

6. The method according to claim 3, characterized in that the catalyst is a catalyst soluble in the reaction medium.

7. The method according to claim 6, characterized in that the formed acid secrete a liquid-phase extraction.

8. The method according to claim 7, characterized in that the extracting solvent is a water.

9. The method according to claim 1 or 2, characterized in that the oxidation of α,ω-hydroxycarbazole compounds is carried out in aqueous phase or in aqueous phase, selected after stage solvent extraction dibasic acids and/or the mother solution crystallization dibasic acids.

10. The method according to claim 9, characterized in that the oxidation of α,ω-hydroxycarbazole compounds is carried out at a temperature in the range from 50°C to 150°C and a partial pressure of oxygen in the range from 0.1 to 30 bar.

11. The method according to claim 9, characterized in that the oxidation of α,ω-hydroxycarbazole compounds is carried out in the presence of a metal catalyst.

12. JV is the FDS in claim 11, characterized in that the metal catalyst selected from the group containing Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Sc, In, Tl, Y, Ga, Ti, Zr, Hf, Ge, Sn, Pb, V, Nb, TA, Cr, Mo, W, Mn, Te, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, lanthanides CE, and combinations of the listed items.

13. The method according to claim 11, characterized in that the catalyst is a deposited catalyst containing active phase formed by one or more elements belonging to the group containing Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Sc, In, Tl, Y, Ga, Ti, Zr, Hf, Ge, Sn, Pb, V, Nb, TA, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, lanthanides CE, and combinations of these elements, and a carrier selected from the group containing aluminum oxide, silicon dioxide, zeolites, charcoal.

14. The method according to item 12, characterized in that the precious metals selected from the group containing gold, platinum, palladium, ruthenium, silver.

15. The method according to claim 1, wherein the cycloaliphatic hydrocarbon selected from the group containing cyclohexane, cyclododecane.

16. The method according to claim 1, characterized in that the solvent is an acid having a lipophilic character.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention refers to the method of adipic acid production by caprolactam oxidation whereat the row materials are caproloctam-containing waste (pot residue from caproloctam production by cyclohexane hydration) with caproloctam content not less than 90% at temperature 75-100oC in liquid media. The reaction is carried out with oxidiser being the mixture of 30% hydrogen peroxide taken in amount H2O2/caproloctam (1-1.1)/1 mole/mole and concentrated sulphuric acid (96%) taken in amount 0.2-0.36 mole per 1 kg of reaction mass whereof the oxidate is acidified with concentrated sulphuric acid for adipic acid separation.

EFFECT: usage of industrial waste, yield enhancing, absence of difficult-to-separate admixtures in commercial adipic acid.

3 cl, 7 ex, 1 tbl

FIELD: chemistry.

SUBSTANCE: invention is related to combined method, which combines olefin epoxidation with preparation of cyclohexanone and cyclohexanol, which are intermediate for production of adipic acid or caprolactam - nylon precursors. Usually cyclohexanone and cyclohexanol are produced by oxidation of cyclohexane with production of cyclohexylhydroperoxide, which is then removed or decomposed. However, in this invention intermediate compound, cyclohexylhydroperoxide is used as oxidant for olefin epoxidation with valuable product making in this process. In process of epoxidation catalyst is used, which contains transition metal and amorphous porous inorganic oxide, which has disorderly interconnected mesopores. The specified mesopores account for at least around 97 volume percents from total volume of mesopores and micropores. Specified porous inorganic oxide has specific area surface from 400 to 1100 m2/g.

EFFECT: porous inorganic oxide is characterised by X-ray picture, having peak from 0,5 to 3,0 degrees 2θ.

13 cl, 5 dwg, 11 ex

FIELD: industrial organic synthesis.

SUBSTANCE: invention provides improved process for production of adipic acid finding use in various fields, e.g. as various product additives, in manufacture of concrete, and as monomer in polymer production. Process consists of oxidizing cyclohexane with oxygen or oxygen-containing gas in presence of solvent based on lipophilic-type monocarboxylic acids containing 7 to 20 carbon atoms and oxidation catalyst, wherein thus formed esters' hydrolysis stage is accomplished by treating reaction medium before extraction of carboxylic acids or treating organic phase obtained from reaction medium after extraction of formed adipic acid, which treatment consists in adding strong acid to medium to be treated, said medium being maintained at temperature above 50°C.

EFFECT: weakened unfavorable effect of esters formed in the process.

16 cl, 5 ex

FIELD: industrial organic synthesis.

SUBSTANCE: invention relates to improved process for production of dicarboxylic acids useful for various applications, for example as additive to various products, in manufacture of concrete, as well as monomers in polymer production. Process consists of oxidizing cyclohexane with oxygen or oxygen-containing gas in presence of oxidation catalyst and lipophilic-type oxidation solvent. Process comprises stage of extraction of dicarboxylic acids formed in oxidation stage, which extraction stage consisting in performing liquid-phase extraction of diatomic acids with the aid of first extraction solvent, wherein at least oxidation solvent and cyclohexane are insoluble, said extraction being carried out in countercurrent liquid-liquid extraction column.

EFFECT: enhanced process efficiency due to efficient diacid extraction stage and complete oxidation solvent recycling.

15 cl, 2 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to the improved method for oxidation of cycloaliphatic hydrocarbons and/or alcohols and ketones in liquid medium with a molecular oxygen-containing oxidizer to acids or polybasic acids. The reaction is carried out in the presence of manganese-base catalyst and organic acid compound of the general formula (I): HOOC-Ar-[R]n wherein Ar means aromatic radical comprising aromatic cycle or some aromatic cycles in condensed form; n means a whole number 1, 2 or 3; R means radical of the general formula (II): wherein R1, R2 and R3 are similar or different and mean alkyl chain comprising from 1 to 4 carbon atoms, or fluorine, chlorine or bromine atom. In more detail, the invention relates to oxidation of cyclohexane and/or cyclohexanol/cyclohexanone to adipic acid with an oxidizer in the presence of aromatic organic acid and manganese-base catalyst. The yield and selectivity by adipic acid are at higher level with respect to yield and selectivity as compared with result obtaining with other solvents and catalysts.

EFFECT: improved oxidation method.

20 cl, 13 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

FIELD: industrial organic synthesis.

SUBSTANCE: invention relates to improved method for production of carboxylic acids and polyacids via liquid-phase oxidation of cyclohexane with molecular oxygen in presence of catalyst: lipophilic acidic organic compound with solubility in water below 10 wt % at 10-30°C, which forms with cyclohexane at least one homogenous liquid phase. Molar ratio of lipophilic acid to catalyst-forming metal lies within a range of 7.0 to 1300. Lipophilic acid is selected from group consisting of 2-ethylhexanoic, decanoic, undecanoic, stearic acids and permethylated derivatives thereof, alkyl(preferably tert-butyl-type)substituted 2-octadecylsuccinic, 2,5-di-tert-butylbenzoic. 4-tert-butylbenzoic, 4-octylbenzoic, tert-butylhydro-o-phthalic, naphthenic, and anthracenic acids, fatty acids, and substituted phthalic acid derivatives.

EFFECT: simplified separation and recycling of oxidation intermediates and catalyst as compared to methods wherein acetic acid is used as solvent.

8 cl, 11 tbl, 26 ex

The invention relates to an improved method for the oxidation of cyclic hydrocarbons, alcohols and/or ketones to carboxylic acids with oxygen or oxygen-containing gas

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

FIELD: industrial organic synthesis.

SUBSTANCE: invention provides improved process for production of adipic acid finding use in various fields, e.g. as various product additives, in manufacture of concrete, and as monomer in polymer production. Process consists of oxidizing cyclohexane with oxygen or oxygen-containing gas in presence of solvent based on lipophilic-type monocarboxylic acids containing 7 to 20 carbon atoms and oxidation catalyst, wherein thus formed esters' hydrolysis stage is accomplished by treating reaction medium before extraction of carboxylic acids or treating organic phase obtained from reaction medium after extraction of formed adipic acid, which treatment consists in adding strong acid to medium to be treated, said medium being maintained at temperature above 50°C.

EFFECT: weakened unfavorable effect of esters formed in the process.

16 cl, 5 ex

FIELD: industrial organic synthesis.

SUBSTANCE: invention relates to improved process for production of dicarboxylic acids useful for various applications, for example as additive to various products, in manufacture of concrete, as well as monomers in polymer production. Process consists of oxidizing cyclohexane with oxygen or oxygen-containing gas in presence of oxidation catalyst and lipophilic-type oxidation solvent. Process comprises stage of extraction of dicarboxylic acids formed in oxidation stage, which extraction stage consisting in performing liquid-phase extraction of diatomic acids with the aid of first extraction solvent, wherein at least oxidation solvent and cyclohexane are insoluble, said extraction being carried out in countercurrent liquid-liquid extraction column.

EFFECT: enhanced process efficiency due to efficient diacid extraction stage and complete oxidation solvent recycling.

15 cl, 2 ex

FIELD: chemical technology of organic substances.

SUBSTANCE: copper (II) salts with dicarboxylic acids are prepared by crystallization from reaction aqueous solution obtained by mixing reagent as source of dicarboxylic acid anion and waste from radio-electronic manufacturing - spent solution in etching printed boards. Solutions containing copper (II), ammonia or mineral acid, ammonium salts and other substances are used as the spent solution in etching printed boards. Dicarboxylic acid, dicarboxylic acid anhydride, dicarboxylic acid salt with sodium, potassium, ammonium or aqueous solutions of these substances are used as reagent representing the source of dicarboxylic acid anion. Prepared copper (II) salts can be used in manufacturing high-temperature superconductors, as fungicides and copper microfertilizers in agriculture, medicinal agents in veterinary science, for antibacterial treatment of water and in other fields. Invention provides reducing cost of products, retention of their purity, utilization of waste in radio-electronic manufacturing (spent solution in etching printed boards of different composite).

EFFECT: improved method for preparing.

18 cl, 1 tbl, 8 ex

The invention relates to an improved method for the oxidation of cyclic hydrocarbons, alcohols and/or ketones to carboxylic acids with oxygen or oxygen-containing gas

The invention relates to an improved method of processing the reaction mixture formed by the reaction of direct oxidation of hydrocarbons to carboxylic acids
The invention relates to the production of decislon or mixtures of decislon from aqueous solutions resulting from the leaching oxidation products of cyclohexane

The invention relates to new derivatives of 5-phenoxyethyl-2,4-preparations of thiazolidinediones General formula I, where a is unbranched or branched C2-C16-alkylenes group, which is saturated and optionally substituted by hydroxy or phenyl; D is a mono - or decillions aromatic group which may contain one or two oxygen atom; X denotes hydrogen, C1-C6-alkyl, alkoxyalkyl group, halogen, cyano, carboxy; n is an integer from 1-3; with the proviso that if a represents a butylene,is not 4-chloraniline group; in free form or in the form of pharmacologically acceptable salts

The invention relates to a method of hydroxycarbonate lactones, more specifically different valerolactone and their isomers, by entering into interaction with carbon monoxide and water in order to obtain the corresponding decollate

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of purifying carboxylic acid from a mixture which contains one or more carboxylic acids selected from a group consisting of terephthalic acid, isophthalic acid, orthophthalic acid and their mixtures, and also contains one or more substances selected from a group consisting of carboxybenzaldehyde, toluic acid and xylene. The method involves: bringing the mixture into contact with a selective solvent for crystallisation at temperature and in a period of time sufficient for formation of a suspension of a complex salt of carboxylic acid with the selective solvent for crystallisation without complete dissolution of the complex salt of carboxylic acid; extraction of the complex salt and decomposition of the complex salt in the selective solvent for crystallisation in order to obtain free carboxylic acid. The mixture containing unpurified carboxylic acid is brought into contact with the selective solvent for crystallisation in order to form a suspension of a complex salt of carboxylic acid with the selective solvent for crystallisation. The complex salt is extracted and, if desired, processed for extraction of free carboxylic acid.

EFFECT: methods are especially suitable for purifying aromatic dibasic carboxylic acids such as terephthalic acid, and also enables reduction of the degree of contamination of phthalic acids with carboxybenzaldehyde isomers.

22 cl, 3 tbl, 1 dwg, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of preparing a dry residue of aromatic dicarboxylic acid containing 8-14 carbon atoms, suitable for use as starting material for synthesis of polyester, where the said method involves the following sequence of stages, for example: (a) oxidation of aromatic material in the oxidation zone to obtain a suspension of carboxylic acid; (b) removal of impurities from the suspension of aromatic dicarboxylic acid in the liquid-phase mass-transfer zone where at least 5% liquid is removed, with formation of a residue or suspension of aromatic dicarboxylic acid, and a stream of mother solution, where the liquid-phase mass-transfer zone includes a device for separating solid substance and liquid; (c) removal of residual impurities from the suspension or residue of aromatic dicarboxylic acid obtained at stage (b) in the zone for countercurrent washing with a solvent to obtain a residue of aromatic dicarboxylic acid with the solvent and a stream of mother solution together with the solvent, where the number of steps for countercurrent washing ranges from 1 to 8, and the countercurrent washing zone includes at least one device for separating solid substance and liquid, and the said solvent contains acetic acid, (d) removal of part of the solvent from the residue of aromatic dicarboxylic acid together with the solvent obtained at stage (c) in the zone for countercurrent washing with water to obtain a residue of aromatic dicarboxylic acid wetted with water and a stream of liquid by-products together with the solvent/water, where the number of countercurrent washing ranges from 1 to 8, and the countercurrent washing zone includes at least one device for separating solid substance and liquid, where stages (b), (c) and (d) are combined into a single liquid-phase mass-transfer zone, and directing the residue of aromatic dicarboxylic acid wetted with water directly to the next stage (e), (e) drying the said residue of aromatic dicarboxylic acid wetted with water in the drying zone to obtain the said dry residue of aromatic dicarboxylic acid suitable for synthesis of polyester, where the said residue wetted with water retains the form of residue between stages (d) and (e).

EFFECT: design of an improved version of the method of preparing dry residue of aromatic dicarboxylic acid.

21 cl, 4 dwg

Up!