SU793995A1 - Method of preparing highest aliphatic acid esters - Google Patents

Description

one

The invention relates to the field of organic chemistry, specifically, to an improved method for the preparation of esters of higher fatty acids, which are important intermediates in the synthesis of higher alcohols, plasticizers, synthetic scrubbers, their agents, surfactants.

A known industrial process for the production of fatty acid esters in a cap plate column column. The reaction is carried out according to the counterflow method: overheated methanol vapors (120-130 ° C) are fed to the bottom of the column, and fatty acids (115-120 ° C) come in from the top along with 50% sulfuric acid in the amount of 1-2%. Methanol is taken in the ratio of 5: 1 to acids. The resulting methyl esters have a residual acid number of 5-7 mg KOH / g.

The depth of esterification reaches 97-980/0.

However, the process is accompanied by a strong resinification and large losses of the starting acid, in addition, the target product requires a long and thorough purification from acid and tar products 1.

There is also known a method for the esterification of monocarboxylic acids: FFA fraction of CiQ-Ci8, oleic, azelaic and sebacic methanol in the presence of titanium dioxide, activated with sulfuric acid, at a temperature of 135 ° C, molar ratio of acid and alcohol 1: 10 for 0.2-1 Part 2. However, the process is also complicated by the additional purification of the esters obtained due to the presence of sulfuric acid in them and the resinification. The degree of conversion of acids in these conditions does not exceed 90%.

The closest in technical essence and the achieved results is a method of producing esters of higher fatty acids, for example, propyl methyl ester of myristic acid, by reacting myristic acid with propargyl alcohol, at a molar ratio of acid and alcohol of 1: 1.2, in benzene, in presence of sulfo cation exchanger

KU-2 as a catalyst, taken in an amount of 20 wt.%, At the boiling point of the reaction mass, for 9 h 3.

The yield of the target product is 95%.

The disadvantages of this method are the duration of the process, as well as the insufficiently high yield and quality of the target product. , .

The purpose of the invention is to accelerate the process and increase the yield of the target product.

The goal is achieved by the described method of obtaining esters of higher fatty acids by reacting the fatty acid Syu-GIS with the corresponding aliphatic alcohol Ci-C3, at a molar ratio of acid to alcohol 1: 1-5, in the presence of sulfonic cation exchanger - sulfopolyfenylene ketone, taken in an amount of 10- 30 wt.% In terms of acid, at a temperature of 140-180 ° C. The process takes 0.5-1 hours.

The yield of the target product is 96-99%.

As a heterogeneous catalyst in the process using heat-resistant sulfonic cation-sulfopolyphenylene ketone. Sulfonated polyphenylene ketone is a polymer with a system of conjugated bonds with the formula:

Due to the presence of a developed polyconjugated structure, the proposed catalyst inhibits such reactions leading to tarring, with the result that an uncolored, better quality target product is obtained.

Example 1. In a cylindrical reactor with a stirrer, a thermometer, an oil jacket, 6, 44 g of sulfopolyphenylene ketone, 22.8 g (0.1 M) myristic acid are loaded. Methanol and nitrogen are fed to the reactor at the reaction temperature of 160 ° C from the bottom into the reactor. The alcohol feed rate does not affect the conversion of myristic acid. Excess methanol, together with the water formed, is removed from the reactor through a cooler to a receiving flask. The total consumption of methanol 20 ml, the ratio of acid and alcohol 1; five.

The process is carried out for 30 minutes. After completion of the reaction, the reaction mass is filtered from the catalyst and subjected to vacuum distillation. 24.12 g of ether are obtained. The yield of myristic acid methyl ester is 99%. Acid number 0.06 mg KOH / g.

Example 2. Under similar conditions, the reaction was carried out at 140 ° C. The reaction is completed in 45 minutes, the consumption of methanol is 30 ml. The output and quality of the air are the same.

Example 3. Under conditions similar to those described in Example 1, 6.43 g (30 wt.%) Of the ion exchanger — sulfopolyphenylene ketone and 21.43 g (0.1 M) of the Ssu – Ci6 FFA fraction (K. Ch. 269, 7 mg KOH / G, E. Ch. 9 mg KOH / G, carbonyl number 6.1 mg KOH / g, iodine number 10.4 g Ig / lOO g). Methanol is passed through the reactor at a temperature of 180 ° C in a stream of nitrogen for 30 minutes. The reaction mass is treated in the same way as in Example 1. The yield of the mixture of esters of the fatty acid fraction is 98%, K. H. 3.1, E. H. 254, CO 4.7, neylyl 1.4, I. H. 7.5.

Example 4. The test was carried out as described in Nimer 1, except that the amount of catalyst was 4.56 g (20% by weight, calculated as acid), the reaction temperature was 180 ° C, the amount of leaked methyl alcohol was 4 ml (ratio alcohol and acid is 1: 1). The yield of myristic acid methyl ester is 96%, the acid number is 2.5 mg KOH / g.

Example 5. In the same way as described in example 1, 6.84 g of catalyst, 22.8 g of myristic acid, 11.5 ml (the ratio of alcohol and acid is 2: 1) of propargyl alcohol are loaded. The reaction is carried out at 1bO ° C for 1 h.

The yield of lopargyl ester is 97.5%. The ester is colorless, does not contain polymeric impurities, the acid number of the ester is 0.05 mg KOH / g, the ester number is 213 mg KOH / g (theoretical E. 4.-214.3 mg / g). For comparison. C. Ch. And E. Ch. Iropargyl ester of myristic acid, obtained by the method of the prototype, is 2 and 210 mg KOH / g, respectively. The ester has a dark color due to the dissolved polymer of propargyl alcohol polyoxivinylene.

Example 6. The experiment was carried out as described in Example 5, except that the amount of catalyst was 2.28 g (10% based on acid), the reaction time was 2 hours. The yield of propargyl ether was 96%.

The use of the proposed invention will significantly simplify the technology by shortening the reaction time, eliminating a large amount of non-utilizable wastewater acids, and eliminating corrosive sulfuric acid. In addition, the high purity of the target product eliminates the final stage of its purification.

Claims (2)

Invention Formula The method of producing esters of higher fatty acids by reacting the fatty acid Xyu-Ci6 with the corresponding aliphatic alcohol Ci-C3, when heated, in the presence of sulfonic cation exchanger, as a catalyst, characterized in that, in order to accelerate the process and increase the yield of the target product, As a sulfonic cation exchanger, sulfopolyphenylene ketone is used in an amount of 10-30 wt.% based on the acid and the process carried out at a temperature of 140-180 ° C and a ratio of 1: 1-5. Sources of information taken into account in the examination 1. SM Loktev et al. Higher fatty alcohols. M., “Himi, 1970, p. 94. 2.Sergeev V.F., Linchevsky F.V., Mayorov D.M. Esterification of sebacic acid with methanol in the presence of titanium dioxide activated with sulfuric acid .- “Oil refining and petrochemistry, 1977, DGD 5, p. 37. Ergashev M. S., Ilkhamdzhanov P., et al. On the kinetics of the esterification reaction of fatty acids with propargyl alcohol. Uzbek chemical journal. 1977. № 1, p. 67-68 (prototype).