SU1097631A1 - Process for preparing s-methyldichlorothiophosphate - Google Patents

Abstract

METHOD FOR OBTAINING 8-METSH1DIH1URPHIOPHPATATE by isomerization of 0-methyldichlorothiofs sphate when heated in the presence of an amine catalyst, which, in order to simplify the process and increase the yield of the target product, is used as an amine catalyst, composition copolymer, wt.%: 2 -methyl-5-vincpiridine 85-90, divinyl-benzene 10-15, and heating lead to a temperature of 75-80 C.

Description

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The invention relates to the chemistry of organophosphorus compounds, in particular to an improved method for the preparation of S-methyldichlorothiophosphate, which can be used as a starting material for the synthesis of various physiologically active compounds.

A known method for producing S-alkyl dichlorothiophosphate by isomerization of alkyl dichlorothionophosphate at 120 sec. H1.1

However, when using high temperature, the process becomes difficult to control due to its exothermicity.

The closest to the proposed technical essence and the achieved result is the method of obtaining 8-methy. 11 dichlorothiophosphate, which is that 0-methyldichlorothiophosphate is subjected to isomerization at 90-100 0 in the presence of a tertiary amine as catalyst. 21

The disadvantages of this method are the use of a toxic tertiary amine, the difficulties associated with the separation of the target product from the catalyst, and the low yield of the target product.

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

The goal is achieved according to the method of producing S-methyldichlorophosphate, which consists in that O-methydichlorothiophosphate is subjected to isomerization by heating to a temperature of 75-80 ° C in the presence of a catalyst of the copolymer composition, wt.%: 2-methyl-5-vinylpyridine 85- 90, divinylbenzene 10-15.

The kinetic studies of the isomerization process of 0-methyldichlorophosphate showed that it is autocatalytic in nature. In order to safely conduct this process under industrial conditions, it is impractical to increase the temperature above 80 ° C. It should also be noted that at temperatures below 75 s, a long process is observed.

In experiments on the isomerization of C-metidiportic phosphate, an industrial copolymer of the AN-251 grade (TU 6-08-24-785-72-) with a constant composition is used.

The catalyst may be used more than once, however, with each subsequent use of the rate, the isomerization process decreases slightly. Thus, after the separation of the target product, a new portion of 0-methyldichlorothiophosphate is added to the catalyst and the process is carried out under the same conditions.

Isomerization of an individual 0-metsvdikhlortiofosfat proceeds similarly to the industrial O-methyldichlorothiophosphate.

Approximately 1. Isomerization is subjected to an industrial product with a content of 85% 0-methyldichlorothiophosphate, 6% 0,0-dimesh1khlortiofosfat and 3% S-methyldichlorothiophosphate, the rest is volatile impurities (phosphorus thiochloroxy, methyl chloride, etc.),

  1.5180, df 1.4776, t. Kip.

37-38 ° C (10 mm Hg).

A mixture of 42.3 g of 0-methyl chlorostiphosphate and 4.2 g of a copolymer of 2-methyl-5-vinylpyridine with divinylbenzene is heated to and maintained at this temperature until the end of the reaction. The process was monitored by gas chromatography, for which samples were taken from the reaction mixture at regular intervals, diluted with dry chloroform and chromatographed.

Chromatography conditions: LHM-8MD chromatograph with flame ionization detector, solid carrier — N-AW-flMCS crimaton, stationary phase — 5% SE — 30. Column length 1.5 m, inner diameter 3 mm, evaporator temperature 125 ° С, column 100 ° C. Gas consumption: carrier (nitrogen) 20-24, air 240-280, hydrogen 20-24 ml / min.

After reaching a temperature of 80 ° C, the degree of conversion is after 10 minutes 0.55, 20 minutes 0.78, 30 minutes 0.89, 40 minutes 0.95.

The 0,0-dimethylchlorothiophosphate present in the starting product does not change during the reaction.

After re-use of the catalyst, a conversion degree of 0.95 is reached after 50, three times 80, four-folds, a full 160 minutes.

The desired product after separation of the catalyst by filtration contains

Claims (1)

METHOD FOR PRODUCING S-METHYLDHLORTHIOPHOSPHATE by isomerization of O-methyldichlorothiophosphate when heated in the presence of an amine catalyst, which is based on the fact that, in order to simplify the process and increase the yield of the target product, a composition copolymer is used as amine catalyst, wt.%: 2-methyl-5-vinylpyridine 85-90, divinyl benzene 10-15, and heating is carried out to a temperature of 75-80 ° C. 1 1097631 *