CS219687B1 - A method for preparing diphenyl esters of o-phthalic acid - Google Patents

Abstract

The invention provides a method for preparing diphenyl esters of phthalic acid from phthalic anhydride and diphenyl esters or di-o-tolyl ester of sulfurous acid in their molar ratio of 1:1.0 to 1.1. The reaction takes place in an inert solvent environment in the presence of 0.0025 to 0.1 mol of organic nitrogenous base at a temperature of 100 to 120 °C for 6 to 12 hours. Diphenyl esters of phthalic acid can be used as auxiliaries, especially as plasticizers for plastics.

Description

3

The invention relates to a process for the preparation of diphenyl ester ether-phthalic acid.

Diaryl esters of o-phthalic acid cannot be prepared by conventional means from phthalic anhydride and phenol in the presence of either basic or acidic catalysts. In this way, only monoaryl esters of phthalic acid and phenol can be prepared at relatively low temperatures. In attempts to prepare the phthalic acid diaryl ester at a higher temperature from the phthalic acid monoaryl ester and the other phenol molecule, the isolated phenol and the cyrophthalic anhydride were back-dried. Of these, the diaryl esters have so far been reliably prepared by reacting phthalic dichloride and two molecules of the corresponding phenol or an alkaline salt thereof (Schrader, Ber. 7,705; Pawlewski, Ber. 28, 108; Mayer, Ber., 26,209; Blicke, Weinkavf, J. Am. Chem., Soc., 54, 330 (1932), and the attention of the monoaryl ester of phthalic acid and phenol in the presence of a chlorinating agent such as phosphoropenta chloride both in the presence of a solvent and a solvent (Bischoff, Hedenstrom) U.S. Patent No. 3,076,837) as well as a process for the preparation of diaryl esters of carboxylic acids from the corresponding acid and diaryl carbonates in the presence of alkaline earth metal oxides or in the presence of hydroxides, alcoholates or tertiary organic amines; is under reduced pressure and in a temperature range of 80 to 30 ° C (DAS No. 1 115 252).

The drawbacks of the above mentioned methods are substantially eliminated in the process of the preparation of diphenyl esters of phthalic acid according to the invention by the fact that phthalic anhydride is reacted with diphenyl ester or di-o-tolylester of sulfuric acid in a molar ratio of 1: 1.0 to 1.1 in for Centrifuge the inert solvent and in the presence of 0.0025 to 0.1 mol of the organic nitrogen base with a temperature of 100 to 120 ° C for 6 to 12 hours. Proceed in such a way that the organic nitrogen base is used as the solvent in the inert solvent. in which the described reaction is carried out under the same conditions as mentioned above. According to the process of the invention, diaryl esters of phthalic acid are prepared which can be used as such. excipients, in particular as plasticizers for plastics. It is an advantage of the process of the invention that the desired diphenyl ester or substituted diphenyl ester of phthalic acid is formed in high yield and relatively high purity. The re-action can be carried out in a conventional device and at a low temperature. After completion of the reaction, the solvent is distilled off and the crude phthalic acid diethyl ester thus obtained can be used for technical practice, or the product can be purified, preferably by recrystallization from n-heptane, to obtain a high purity high purity product.

The subject matter of the invention is described in the examples of the invention, without being limited thereto. tions. Example 219687.

2.96 g (0.02 mole) of phthalic anhydride and 5.15 g (0.022 mole) of sulphurous acid difenyl ester were added to a 1000 ml Erlenmeyer flask and 10 ml of pyridine was added. The reaction mixture was stirred and heated under reflux for 10 hours at 115 ° C. After! pyridine was distilled off under reduced pressure. The remainder is the crystalline product - thiophenyl phthalic ester, obtained in practice in quantitative yield. The crystallization of n-heptane gave 5.8 g (91.2% yield), and after the mother liquor was worked up, 0.4 g (6.3% yield) of a colorless crystalline product of melting point 71 was obtained. ° C. The total yield is 97.48%. Example 2

Proceeding as in Example 1, except that the ratio of reacting components was changed to 2.96 g (0.02 mole) of phthalic anhydride, 4.68 g (0.02 mole) of sulphurous sulfonyl ester was used and the reaction time was extended to 12 hours . After crystallization from n-heptane, 5.0 g (78.6%) of phthalic acid difenyl ester was obtained and after processing of the mother liquor, 0.6 g (9.43%) was obtained, which together represented 5.6 g, i.e. 88.05% yield. Example 3 ·.

The procedure was as in Example 2, but the reaction time was reduced to 6 hours. A total of 4.8 g (75.4% yield) of the phthalic acid phenylene ester was obtained. ; Example 4

The procedure was as in Example 1 except that pyridine was distilled under reduced pressure after completion of the reaction. 6.31 g (99.2% yield) of phthalic acid phenylene ester were obtained. The product thus obtained can be used directly, as a technical product, without prior purification. Example 5

The procedure was as in Example 1 except that toluene was used as the solvent in 10 ml (8.7 g) and 0.2 g (0.0025 mol) of pyridine was used as catalyst. The reaction temperature was 111 ° C and the reaction duration was increased to 13 hours. The yield of phthalic acid difenyl ester is 4.2 g (66.4% yield). Example 6

The procedure was as in Example 5 except that 7.9 g (0.1 mol) of pyridine was used as the catalyst. The yield of phthalic acid difenyl ester was 5.4 g (84.9% yield). Example 7

The procedure was as in Example 5 except that instead of pyridine it was used as the catalyst

Claims (1)

4 3-methylpyridine. 5.8 g (91.2% yield) of diphenyl ester of phthalic acid were obtained in the usual manner. Example 8 2.96 g of phthalic anhydride and 5.8 g of 219687 (0.022 mol) of o-tolylester of sulfuric acid were weighed into a 100 ml Erlenmeyer flask and 10 ml of pyridine was added. The method of preparation was the same as in Example 1, the reaction time was 10 hours. Crystallization from n-heptane and after mother liquor treatment yielded 6.81 g (98.2% yield) of product. OBJECT OF THE PREPARATION A method of preparing o-phthalic acid diphenyl esters, characterized in that phthalic anhydride is reacted with diphenyl ester or di-o-tolylester sulphurous acid in a molar ratio of 1: 1.0 to 1.1 of the invention in an inert solvent and in the presence of 0.0025 to 0.25%. 0.1 mole of organic nitrogen base was heated to 100-120 ° C for 6-12 hours. Printed by Moravian Printing Works, Price: 2,40 Kčs operation 12, Leninova 21, Olomouc