SU950719A1 - Process for producing propylthioformiate - Google Patents

Description

The invention relates to a new process for the preparation of propylthioformate of the formula CH (0) 5C3H7, which is used in various organic syntheses, in particular, it is used as a strong acylating agent.

Processes for the preparation of thiocarboxylic acid esters are known, for example, by acylation of mercaptans C3H. The method for producing propylthioformate is the closest to the one proposed, which consists in the treatment of propanthiol with a mixture of formic acid and acetic anhydride (1: 1 molar ratio) in the presence of a mixture of acetic acid and acetic anhydride lyster, for example, pyridine or triethylamine or p-toluenesulfonic acid at 20-60 ° C for 24 hours. After aging, the reaction mass is poured into a saturated solution of barium hydroxide, the organic layer is separated and gon removed and the desired product is isolated in a yield of 75-77% 2.

However, this method is characterized by a low yield of the target product and the duration of the process.

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

The goal is achieved by the fact that according to the method of producing propylthioformate, 1,3-oxathian is isomerized in the presence of tert-butyl peroxide at a molar ratio of initial reagents equal to 4: (O, 3-0.5) in an autoclave and a temperature of 140-150 ° C .

The desired product is distilled in vacuo. The product yield is 8591%. The process time is 1.5-4.5 hours.

Example 1. A 600 ml stainless steel autoclave is charged with a volume of 600 ml of 416 g (4-mol) of 1,3-oxathian, 73 g (0.5 mol) of tert-butyl peroxide. The contents were flushed with nitrogen for 10 minutes, then the autoclave was closed and heated at 150 ° C for 90 minutes. After cooling, the reaction mass is distilled under low vacuum. Propyl thioformate is formed in the amount of 88.4 g (85% of the theoretical) per converted substrate. T. Kip. 45C / 40 mmHg, p 1.4668.

Found,%: C 46.21; And 7.71; S 30.72.

C4.Hg OS

Calculated,%: .C 46,11; H 7.76; S 30.78.

HMR spectrum 7.03 (C, 1I, HCOS); 2.75 (t, 2H, CHiS); 1.2-1.4 (m., 2H, CHj); 0.83 (t., 3N, CHj).

Example 2. The reaction was carried out similarly to example 1 with a molar ratio of reagents 1,3-oxathian1 tert-butyl peroxide 4.0: 0.5, at 4.5 h. 93.6 g (90% of the theoretical) propylthioformate was isolated.

Example 3. The reaction is carried out as in Example 1, with the primol ratio of 1,3-oxathian1 tert-butyl peroxide 4 Q, 3. Allocate

89.4g {86% of theoretical) Pro PiltiOformate ..: Example 4. The reaction is carried out

as in Example 1 at 5 h at a ratio of 1,3-oxathian: feather: cis tert-butyl 4jO, 3. Highlight.

91.5g (83% of theoretical), propylthioformate.

Example 5 The reaction is carried out similarly to Example 1 at 150 ° C90 min and at a ratio of reagents of 1,3-oxathian: tert-butyl peroxide 4.0: 0.4. 92 g (91% of the theoretical per transformed substrate) are recovered.

Example. 6. The reaction is carried out analogously to example 1 at 140 ° C for 4.5 hours with a ratio of reagents 1,3-oxathian tert-butyl peroxide 4.0-: 0.4, 91 g are recovered (90% of the theoretical per substrate converted ).

The use of the proposed method allows increasing the yield of propylthioformate from 75 to 91% and reducing the synthesis time from 24 to 1.5-4.5 hours.

Claims (2)

1. Short, Chemical Encyclopedia. V. 5, M., 1967, p. 155. 2.RZH Him, 20ZH, 1971, p. 147 (prototype).