SU1384575A1 - Method of producing 3-ethylthiobutanal - Google Patents

Abstract

The invention relates to mercaptans, in particular, to the preparation of 3-ethylthiobutanal (ETB), which is used in the synthesis of herbicides. In order to simplify and intensify the process, the interaction of crotonaldehyde with ethyl mercaptan in the presence of triethylamine is carried out in a molar ratio of 1: 0.9-1.1: 0.0002-0,0006, respectively, and 32-37 ° C. The method eliminates the use of toxic solvent apetonitrile. The process time is 5 hours versus 15 hours by a known method.

Description

00 00 4

cl

one

This invention relates to an improved process for the preparation of 3-ethylthiobutane.

(СН, СНСН, СНО).,. I L1;

I

S-CjH;

which is used as an intermediate product in the synthesis of herbicides.

The purpose of the invention is to simplify and intensify the process, which is achieved by carrying out the process of the interaction of crotonaldehyde with ethyl mercaptan in the presence of triethylamine at a molar ratio of 1: 0.9-1.1: 0.0002-0,0006, respectively, and 32 -37 seconds

The invention is illustrated by the following examples.

Example 1. In a round bottom flask equipped with a mechanical stirrer, a reflux condenser and a thermometer were added 1207 g (18.69 mol) of ethyl mercaptan (mass fraction 96%), 1 ml (0.007 mol) of triethylamine and with stirring and at a temperature of 33-35 ° C, 1349 g (18.69 mol) of crotonic aldehyde (mass fraction 97%) is added. The indicated temperature is maintained for the first 1.5 hours by cooling the reaction flask with cold water and heated for a further 3.5 hours. At the end of the reaction, unreacted crotonic aldehyde, ethyl mercaptan and

triethylamine is distilled at

-about

lowered

about heating to 50 C,

pressure 20-25 C and collect 114.4 g of distillate containing 21.2% of the target product (I). The distillate obtained is returned to the process of obtaining thioaldehyde. VAT residue in the amount of 2441.6 g with a mass fraction of thioaldehyde (I) 97 without further purification is used in the synthesis of the herbicide sethoxydim. The yield of thioaldehyde to crotonaldehyde taken is 96%, n = 1.4730, do 0.97.

%;

 Found 24.0.

Calculated, 4, Q.

IR spectrum:

C 54.3 | H 9.0; I: C 54.5; H 9.0;

1732

(C1H) cm; PMR spectrum: (СРС1,), if, 1.26 (t, ЗН, .СНз-СН); 1.36 (d, 3N,) 5 2.64 (m, 4H-CHi-, CH, CH) | 3.31 (m, 1H, -CH-); 9.77 (s, 1H-CHO) m, d.

Example 2. The interaction of 1300 g (18.01 mol) of crotonic aldehyde with a mass fraction of the main wave 1384575

97% g (19.81 mol) of ethyl mercaptan with a mass fraction of the main substance of 96% in the presence of 1.5 ml (0.010 mol) of triztilamine at 34-37 ° C for 5 hours under the conditions of Example 1 are obtained 2402 g (17 , 29 mol) of thioaldehyde (I) with a mass fraction of the main substance of 95%. The yield of the desired product on crotonaldehyde taken is 96%.

At me rz. From 1536 g (21.28 mol) of crotonaldehyde with a mass fraction of the main substance of 97% and 1250 g (19.3.5 mol) of ethyl mercaptan with a mass fraction of the main substance of 96% in

the presence of 0.6 ml (0,004) at 32-35

ra

C for 6 h 1 get 2528

in the conditions of example (18.19 mol)

0

five

0

five

0 5

0

five

thioaldehyde (I) with a mass fraction of the main substance of 95%. The yield of the product based on ethyl mercaptan taken is 94%.

Example 4: From 1690 g (23.418 mol) of crotonaldehyde with a mass fraction of the main substance of 97% and 1250 g (19.35 mol) of ethyl mercaptan with a mass fraction of the substance of 96% in the presence of 1.2 ml (0.008 mol) of triethylamine (mixing ratio 1 , 2: 1: 0.008) at 34-36 ° C for 7 hours, in the conditions of Example 1, 2636 g (17.77 mol) of thioaldehyde (I) are obtained with a mass fraction of the basic substance of 89%. The yield of the product based on ethyl mercaptan taken is 92%.

Example 5: Out of 1,300 g (18.01 mol) of croton. aldehyde with a mass fraction of the basic substance of 97% and 1395 g (21.61 mol) of ethyl mercaptan with a mass fraction of the basic substance of 96% in the presence of 1.2 ml (0.008 mol) of triethylamine (mixing ratio 1: 1.2: 0.008) at 34 37 ° C for H under the conditions of Example 1, 2486 g (16.39 mol) of thioaldehyde (I) are obtained with a mass fraction of the basic substance of 97%. Product yield for crotonaldehyde taken 91%.

Thus, the proposed method is simpler known, since the use of the toxic solvent acetonitrile is eliminated and the complicated procedure of the target product is simplified, and the process itself is accelerated - the time is 5 hours against 15 hours.

F o rmula of the invention

The method for the preparation of 3-ethylthiobutane by the interaction of croton aldegy 3. 13845754

yes with ethyl mercaptan in the presence of | carried out at a molar ratio

triethylamine distinguishing-initial reagents, equal to 1: 0.9 with the fact that, in order to simplify and 1.1: 0.0002-0.0006, respectively,

process intensification, last, and 32-37 s.

Claims (1)

Claim The method of producing 3-ethylthiobutanal by the interaction of crotonic aldehyde 3 and ethdlmercaptan in the presence of triethylamine / characterized in that, in order to simplify and intensify the process, the latter is carried out at a molar ratio of the starting reagents equal to 1: 0.91.1: 0.0002 -0,0006, respectively, and 32-37 ° С.