RU982317C - Method of producing aliphatic dicarboxylic actids - Google Patents

Abstract

METHOD FOR PRODUCING ALIPHATIC DICARBOXYLIC ACIDS based on the corresponding diester using water when heated, followed by isolation and crystallization. cijeic acid. characterized in that, in order to increase the yield of the target product and simplify the process, the treatment with diester-ledutaliphatic monocarboxylic acid containing from 1 to 3 carbon atoms in the presence of water and mineral acid with a ratio of diester: monocarboxylic acid: water: mineral acid 11-27 ; 28-216: 0.6-306: 1 at a temperature of 90-110% with simultaneous withdrawal of the resulting monoester from the reaction sphere.

Description

The invention relates to the field of chemical technology, and in particular to a method for producing aliphatic dicarboxylic acids, which are a valuable raw material for the production of dyes, agricultural growth stimulants, as well as plasticizers.

The aim of the invention is to increase the yield of the target product and to simplify the process.

The goal is achieved by the proposed method for producing aliphatic dicarboxylic acids containing from 4 to 10 carbon atoms, which consists in treating the corresponding diester with an excess of aliphatic monocarboxylic acid containing from 1 to 3 carbon atoms in the presence of water and mineral acid. at a ratio of diester: monocarbam6va acid: water: mineral acid 11 27: 28-216: 0.6-306: 1 at a temperature of 100 110 ° C with simultaneous withdrawal of the resulting monoester and subsequent crystallization of the target product. The acid yield is 77-97%.

Hallmarks of the process

O 00 is the treatment of disphyr with an excess of aliphatic monocarboxylic acid containing from 1 to 3 carbon atoms of the genus, in the presence of water and mineral

C) acids at a ratio of diester: monocarboxylic acid: water: mineral acid VI 11-27: 28-216: 0.6-306: 1, at a temperature of 100-110 ° C with simultaneous withdrawal of the resulting ether, which allows to increase the yield target product and simplify the process.

The method is based on the transesterification reaction of dicarboxylic acid diacyl esters with monocarboxylic acids in the presence of insignificant (from 0.1 to 2 wt.%) Amounts of mineral

acids used as catalysts. In this case, monocarboxylic acid serves as a reagent and a reaction medium. Using this technique makes the proposed method more rational in comparison with hydrolysis. The amount of monocarboxylic acid used in the proposed process is 2-8-fold excess versus stoichiometric.

Adding water to the reaction mixture speeds up the process.

In the table. Figure 1 shows data characterizing the effect of water on the rate of transesterification of dimethylsebacinate with acetic acid in the presence of HNOa.

From the table. 1 it can be seen that the maximum reaction rate is observed in the range of water concentration from the weight of monocarboxylic acid on May 28-70. %, and the speed at the maximum point exceeds the reaction rate in a practically anhydrous medium, ceteris paribus, almost 570 times.

The reaction can be carried out at atmospheric pressure at a temperature of 30-80 ° C higher than the boiling point of the resulting ester of the monocarboxylic acid ester.

After completion of the reaction, the reaction mixture is a solution of substantially pure dicarboxylic acid with water containing unchanged mineral acid, used as a catalyst.

In the case of the preparation of acids having a low solubility in water (e.g., sebacic), the use of monocarboxylic acids as a solvent can significantly improve the process for the isolation of these acids from the reaction mixture. The resulting dicarboxylic acids are recrystallized in a known manner from MONOCARBOPIC ACID,

the isolated crystals (suspension) are neutralized with alkaline solutions, mainly ammonia water, in a ratio of 1: 1 (by weight), which allows a 5-7-fold reduction in the amount of washing water (demineralized water). After neutralization, a single washing of the crystals with demineralized water and drying is sufficient, and a high-quality product is obtained. Thus, when comparing the quality indicators (Table 2) of sebacic acid obtained by hydrolysis followed by treatment with 10-47% nitric acid when heated to 90-100 ° C and crystallization (4) and acid / obtained by the proposed method by acidolysis, followed by crystallization from a mixture of water-vinegar

acid, obviously their significant improvement. The proposed method allows to significantly improve one of the most important quality indicators - color number (color

melt). The presence of coloring impurities in the sample obtained after acidolysis. characterized by a value of 1 iodine scale while the sample after hydrolysis has 4 times staining impurities

0 more. Also improved indicators of acid number and permanganate samples.

The source of dialkyl ethers for the proposed process on an industrial scale can be waste from a number of industries: production of caprolactam, adipic acid, oxidation of paraffin hydrocarbons, processing of shale, ozonation of sperm whale fat, etc. As waste in these industries, mixtures of lower dicarboxylic acids (oxalic, glutaric, succinic, adipic).

At present, mixtures of acids which are wastes from the above industries are destroyed (incinerated).

However, these acids (in the form of a mixture) by a known method (etherification with methanol) can be converted into the corresponding

0 dimethyl ethers and distillation a mixture of zfirs divided into individual products.

Data on the molar ratio of reagents. The yield of the desired product and melting point are given in table. 3.

Examples of the reaction flask, as described in example 3, was placed 11.5 g of dimethylacetate ester of sebacic acid, 11.6 g of 98% acetic acid (parts), 18.0 g

0 water and 0.3 g of 98% nitric acid. The mixture is kept for 2 hours at a temperature of 100-102 C. After a reflux condenser in which the water temperature is maintained at 58 ° C, 7.4 g of methyl acetate are condensed.

5 (bp. 57.1 ° C). The resulting reaction mass of sebacic acid contains 29.5%. Esters of sebacic acid are absent. The reaction solution for the isolation of sebacic acid from it slowly

0 cooled to 30 ° C. Crystallized sebacic acid is lecrystallized from 60% acetic acid. After neutralization with ammonia water, washing the precipitated crystals with demineralized water and drying, the product has an acid number of 551 mg KOH / g (theoretical 554.5 mg KO I / g) the color of the melt in units of the iron-cobalt scale 1.

PRI me R 2. In a reaction flask, as described in example 3, is placed t7.4 g of adipic acid dimethyl ether, 9.22 g of formic acid (rga, 99.7% of the basic substance), 4.8 g of water and 0.8 g of 58% nitric acid. The mixture is kept for 2 hours at a temperature of 100-101 ° C. After a reverse cooler, the water temperature of which is maintained at 33 ° C, 12.0 g of methyl formate are condensed. A solution is obtained as a result of the reaction, which quickly hardens upon cooling and contains May 10, 72. % adipic acid. Adipic esters are absent. The acid is isolated analogously to Example 1 and recrystallized from water.

PRI me R 3. In |: a suction flask 15 equipped with a reflux condenser cooled by thermostated water, the temperature of which is chosen so as to ensure condensation of all reagents, with the exception of 20 monocarboxylic acid esters formed during the reaction, placed 14 6 g of dimethyl. succinic acid ester, 9.22 g of formic acid (rga, 99.7% of the basic substance), 8.4 g of water and 0.8 g of 58% nitric acid. 25 The mixture is incubated for 2 hours at a temperature of 100-105 ° C. After the reflux condenser, in which the water temperature is maintained, 12 g of methyl formate (i.e., boiling point) are condensed. The resulting solution contains 30 56 wt.% Succinic acid. The succinic acid esters in the solution are absent. The acid was isolated analogously to Example 1 and crystallized from water.

Example 4. In a reaction flask for carrying out the reaction, Jacques described in Example 1, was placed 23.0 g of sebacic acid dimethyl ester, 48.0 g of 98% acetic acid, 32 g of water and 0 6 g of concentrated II (, 6%) sulfuric acid. A mixture of 40 incubated for 3 hours at a temperature of 90-95 ° C. After the reflux condenser, at which the water temperature was maintained, 14.8 g of methyl acetate were condensed. The resulting reaction mass contains 45 22.5% of sebacic acid. Esters of sebacic acid are absent.

The reaction mass is slowly cooled from 95 to. Precipitated crystals of sebacic acid are separated. The melting point 50 of the obtained sebacic acid 132.7-132.9 ° C, acid number 550 mgKOH / g. Sebacic acid is recrystallized from 20% acetic acid, neutralized, washed with water, 55 acid number 554 mg KOH / g, melt color in iron-cobalt scale units

. 1, mp .133.0-133.2 ° C. Example 5. 16.0 g of glutaric acid dimethyl ester, 14.8 g of propionic acid (h, basic substance content 98%), 8.8 water and 0.4 g 57% are placed in a reaction flask for the reaction as described in Example 3 nitric acid. The mixture was incubated for 2 hours at a temperature not exceeding 102 ° C. After a reflux condenser, the water temperature of which is maintained at 80 ° C, 17.6 g of methylpropionate are condensed (boiling point 79,). The resulting solution contained only glutaric acid, 58.5% by weight. Glutaric acid esters are absent. The acid is isolated as in Example 1 and crystallized from water.

PRI me R 6. In the reaction flask, to carry out the reaction, as described in example 3, was placed 23.0 g of dimethyl ester of sebacic acid, 48.0 g of glacial acetic acid 99.8%), 0.8 g concentrated (95.6%) sulfuric acid. The mixture was incubated for 4 hours at a temperature of 110 ° C. After the reflux condenser, at which the water temperature is maintained, 14.8 g of methyl acetate are condensed. To the resulting reaction mass, the content of sebacic acid was 38% by weight. Esters of sebacic acid are absent.

The reaction solution was slowly cooled from YuODOZO C. The isolated sebacic acid had a temperature of 132.7-132.9 ° C, an acid number of 550 mg KOH / g, then it was recrystallized from 80% acetic acid. After neutralization, washing the precipitated crystals with water and drying, the finished product has an acid number of 554 mgKOH / g, the color of the melt according to the iron-cobalt scale is 1, so pl. 132.8-133.0

EXAMPLE D 7. In a reaction flask as described in Example 3, 17.4 g of adipic acid dimethyl ether, 14.8 g of propionic acid (h 98% of the basic substance) were placed in a reaction flask. 0.4 g of 58% nitric acid and 4.8 g of water. The mixture is incubated for 3 hours at a temperature of 102-104 ° C. After the reflux condenser, at which the water temperature is maintained at 80 ° C, 17.6 g of methylpropionate are condensed. In the resulting solid reaction mass, 73.7 wt.% Adipic acid was found. Adipic esters are absent. The acid is recovered and recrystallized from water.

Example 8. In the reaction flask, as described in example 3, was placed 230.0 g of sebacic acid dimethyl ester, 240.0 g of acetic acid (concentration of 98 wt.%), 103,, 0 g of distilled water and 25 g of 57% nitric acid as a catalyst. The mixture was incubated for 2 hours at a temperature of 100 ° C. After the reflux condenser, the water temperature of which is maintained at 58 ° C, 143.0 g of methyl acetate are condensed (bp. 57 ° C). The weight of the obtained reaction mass A5A, 0 g. The initial dimethylsebation is absent. The content of sebacic acid 44.4 wt.%. Sebacic acid was isolated from this mass. Recrystallized from 60% acetic acid. The weight of dry acid is 192.5 g (95.3% of theory), the acid number is 554.0 mg KOH / g, the melting point is 133.5-134.0 ° C, the color of the melt is according to the iodine scale 1. The content of sebacic acid is 8 and wash water 9.5 g.

Dependence Kef. the rate of acidolysis of dimethylsebacinate from the amount of water (catalysis. torus HNO3 May 2.% temperature)

Example 9. In the reaction flask for the reaction, as described in example 3, was placed 25.8 g of dodecandicarboxylic acid dimethyl ester, 48.0 g of acetic acid (concentration of 98 wt.%), 18.0 g of distilled water and 2.5 g of 57% nitric acid as a catalyst. The mixture is incubated for 2 hours at a temperature of 97-100 ° C.

After the reflux condenser, at which the water temperature was maintained at 58 ° C, 14.3 g of methyl acetate were condensed (kiN. 57 ° C). The weight of the obtained reaction mass is 80.0 g. The starting material of dodecandicarboxylic acid dimethyl ether is absent. Dry dodecandicarboxylic acid J1.9 g (95 wt% of theory) was isolated, mp. 128.2-12V, in ° C.

Table 1

Index

hydrolysis (4)

White crystalline substance Below 134 With an HQ below 550 No more than 4

Table 2

Production method

by the proposed method

White crystalline substance

133.5-134 ° C 554

0.015

0.001 1

Acidolysis of dicarboxylic acid dimethyl esters

Table3