SU1049469A1 - Process for preparing capric acid - Google Patents

Abstract

A method for producing caproic acid by oxidizing cyclohexanone with hydrogen peroxide at room temperature in - ci-oxyhydroperoxide of cyclohexanone followed by its decomposition with an aqueous solution of ferrous sulphate of iron, characterized in that, in order to increase the yield of the target product, the process is carried out in the presence of a metal oxide program. groups comprising magnesium oxide or alkoxy oxide at a molar ratio of -oxy-cyclohexanone: 1: 4-8 metal oxide. § (L

Description

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CD CO. The isobregnation relates to a process for the production of caproic acid, which finds application in the manufacture of plasticizers, lubricating oils and soaps, and the changing of our compositions. Methods are known for the preparation of aliphatic carboxylic acids, including caproic acid, by the oxidation of alcohols, aldehydes and opefins, as well as by carboxylic acid and the carbonylation of olefins G1. However, these methods do not allow to obtain pure acids without impurities of aldehydes, dialkketones, unsaturated compounds, and isostructural compounds, and the conduct of the processes is associated with the use of high pressure, temperature, and catalysts. You get a mixture of carboxylic acids, the content of caproic acid which does not exceed 15 2%. There is also known a method of producing capronic acid with a yield of up to 90% by catalytic hydrogenation of fb-lactone hydroxycaproic acid under pressure in the presence of a catalyst — nickel Rehen 2 J. However, / 5 -lactone hydroxycaproic acid is difficult to access, because it is produced by the condensation of ketene with butaroaldehyde in the presence of a catalyst is associated with great technological difficulties. The closest in technical terms to the present invention is a method of producing caproic acid by oxidizing cyclohexanone with hydrogen peroxide at room temperature in o-oxyhydroperoxide of cyclohexanone with the subsequent decomposition of the aqueous methanol solution of ot-oxyhydroperoxide of cyclohexanone in the presence of ferrous sulfate. The process is carried out simultaneously by mixing 30% hydrogen peroxide, cyclohexanone, methanol and an aqueous solution of ferrous sulphate of iron C3. However, in this process a mixture of products is formed, the content of caproic acid in which does not exceed 30%. The aim of the invention is to increase the yield of the target product. This goal is achieved in that according to the method of producing caproic acid by oxidizing cyclohexanone with hydrogen peroxide at room temperature in ci-oxyhydroperoxide of cyclohexanone, followed by its decomposition with aqueous ferrous sulfate. The process is carried out in the presence of a metal oxide selected from the group comprising magnesium oxide or alqui nium oxide, with a molar ratio of oi-oxyhydroperoxide of cyclohexanone, the metal oxide being 1: 4-8. The method allows to increase the yield of the target product up to 76-99%. Example 1. K16, Og of magnesium oxide 0.2 mol of cyclohexanone (19.6 g), 0.1 mol of hydrogen peroxide (11.0 ml of D03% } -1, p) and 1O ml of methanol with constant stirring. After 1 h to the obtained reaction mass, with a molar ratio of oi. oxyhydroperoxide cyclohexanone: magnesium oxide 1: 4, add a solution of 0.1 ml of FeSO-7H20 (27.8 g), in 1OO ml of water, maintain the temperature of the ISIS C and stir for 2 hours, and then the reaction products are acidified, 0 , 2 N HjSO solution to pH = 2. The organic reaction products are extracted with ether, and the caproic acid is separated by treating the ether extract with an aqueous solution of NOI 2 CO-J. The resulting aqueous solution of the sodium salt of caproic acid is acidified with a 0.2 N solution of N250 and the caproic acid is separated. . 13 yield 5.6 g (98% per reacted cyclohexanone). The ether solution is distilled and cyclohexanone (, 9 g) is recovered which does not react. Example 2. K 2 O, magnesium oxide Og added 0.2 grams of cyclohexanone (19.6 g), 0.1 mop hydrogen peroxide (11.0 ml of 30%) and 10 ml of methanol with constant stirring. After 1 h To the resulting reaction mass, with a molar ratio of o (.- hydroxy-peroxide of cyclohexanone; magnesium oxide 1: 5, add a solution of O, 1 mAb FeSO (27.8 g) in 100 ml of water, maintaining a temperature of 15-18 ° C, and stir further 2 h, and then the reaction products are acidified with a 0.2 N solution of Nl 50. to a pH of 2. The organic reaction products are extracted with c) and the caproic acid is recovered by treatment with ether With the aqueous solution of Noi2CO. The resulting aqueous solution, the sodium salt of caproic acid, was acidified with a 0.2 solution, caproic acid was isolated. The yield was 5.8 g (99% to reacted cyclohexanone). The ether solution was distilled with cyclohexanone (13.8 g ), but “stepping into the reaction.

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Example 3 To 1G, 0 g of magnesium oxide was added 0.2 mol of cyclohexanone (19.6 g), 0.1 mol of hydrogen peroxide (11, O ml) and 10 ml of ethanol with nocTOHHHcevi stirring. After 1 h, a solution of O, 1 mol of FeSOx (27.8 g) in 100 ml of water, maintained at a temperature of 15-IS C, was added to the obtained reaction mass, with a molar ratio of ° C -oxyhydro-cyclohexanone: magnesium oxide: 1: 4 stirred for another 2 hours, and the reaction products were acidified with a 0.2N N250 solution to a pH of 1 2. Organic products of the reaction were extracted with ether, and the caproic acid was separated by treating the ether extract with an aqueous solution. The resulting aqueous solution of capric acid sodium was 0, acidified 2M N2 50 solution and caproic acid was isolated. The output of 5.5 g (97% on reacted cycloxenone). The ether solution is distilled and cyclohexanone (, 9 g) is recovered and unreacted.

Example 1. K 10 2 d oxide al Yu. mini, 0.2 mol of cycloxanone (19.6 g), 0.1 mol of peroxide: - E. hydrogen (11.0 ml of 30% N202) and 10 ml of methanol are added with constant stirring, | after 1 H, a solution of 0.1 mol O (27.8 g) in 10 O ml is added to the resulting reaction mass, with a molar ratio of d.-oxyhydroperoxide of cyclohexanone: aluminum oxide 1: 4.

water, maintaining the temperature at 15-18 ° C and stirring for another 2 hours, and then the reaction products are acidified with a 0.2 M H2O solution to pI 2, the organic reaction products are extracted with ether, and the caproic acid is separated by treating the ether extract with an aqueous No (2CO.j. The resulting wave solution of the sodium salt of caproic acid is acidified with a 0.2 N solution

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  Caproic acid is isolated. The output of 5.2 g (76% on unreacted cyclohexanone). The ether solution is distilled and cyclohexanone (, 8) is recovered, unreacted.

Example 5. To 32, O g M 0, add 0.2 mol of cyclohexanone (19.0 g), mol of hydrogen peroxide (11.0 ml of 30% Hj 0) and 1 (, 0 ml of methanol during reshaping. After 1 h to of the reaction mass (molar ratio of OC-OC and hydroperoxide cycl of hexanone: metal oxide.; &) Add a solution of O, 1 mol of FeSOx. 7H O in 100 ml of water, maintaining the temperature at 15-1 bs and stirring for another 2 hours, and then the reaction products are acidified with a 0.2N H2O solution to pH 2. The organic reaction products are extracted with ether and the caproic acid is isolated by treating the ether extract with an aqueous solution. projectile loader sodium salt solution is acidified O, 2M N2504 and isolated caproic acid Yield 5.70 g (on unreacted cyclohexanone) The ether solution was distilled -... are isolated and unreacted cyclohexanone r (l-13.9 g).

The proposed method for the production of caproic acid is easy to implement, simple in hardware design and safe due to the introduction of significant amounts of an inert carrier of metal oxides. It is based on Tier-available source reagents - 30% hydrogen peroxide and cyclohexanone, in common from other methods that require hard-to-reach reagents, for example

0-olefins or fb-lactone hydroxycaproic acid. The desired product is obtained in high yield up to 99%. Isolation of products is achieved in a simple and affordable way - by distillation, and unreacted cyclohexanone can be recycled again.

Claims (1)

METHOD FOR PRODUCING CAPRIC ACID by oxidizing cyclohexanone with hydrogen peroxide at room temperature in - pt — oxyhydride — cyclohexanone peroxide followed by its decomposition with an aqueous solution of ferrous sulfate, characterized in that, in order to increase the yield of the target product, the process is carried out in the presence of metal oxide, selected from the group comprising magnesium oxide or alumina, with a molar ratio of d-o-and-cyclohexanone hydroperoxide: metal oxide equal to 1: 4-8, "and co • and With