SU376361A1 - METHOD OF OBTAINING TRICHLOROMETHANESULPHENYL CHLORIDE - Google Patents

Description

This invention relates to a process for the preparation of trichloromethanesulfenyl chloride, which is an intermediate in the synthesis of fungicides.

A method of producing trichloromethanesulfenyl chloride (THCMX) is known by chlorinating carbon disulfide in an aqueous medium according to the scheme:

NW, + 5С12 + 4НгО - С1зС5С1 + 6НС1 + Н, 5О4.

As the concentration of TCXMX increases in the reaction mixture, side reactions are observed leading to the formation of carbon tetrachloride and trichloromethane sulfonyl chloride.

The disadvantages of this method are the low speed of the process, insufficient completeness of the absorption of chlorine, the formation of a significant amount of by-products. In addition, a mixture of sulfuric and hydrochloric acids is difficult to utilize as waste.

In order to reduce the amount of by-products, chlorination is proposed to be carried out in the presence of dilute sulfuric acid.

In this case, the resulting hydrogen chloride is stripped from a solution of sulfuric acid, the concentration of which increases significantly as the reaction proceeds, and is adsorbed by water in the columns with adiabatic

absorption, forms commercial abgas hydrochloric acid. At the end of the reaction, sulfuric acid is practically free of hydrogen chloride.

Chlorination is carried out in a dilute solution of sulfuric acid at low temperatures in the absence of a catalyst. An organic layer consisting mainly of trichloromethane sulphenyl chloride with impurities of unreacted carbon disulfide, carbon tetrachloride and trichloromethanesulfonyl chloride is separated from the aqueous layer and fractionated.

The first fraction contains a mixture of carbon disulfide and carbon tetrachloride, the second being separated in vacuum is trichloromethisulfenyl chloride (purity less than 99.0%). VAT residue represents

a melt of trichloromethisulfenyl chloride.

Example 1. In a four-necked flask equipped with a bubbler to deliver chlorine,

a thermometer, a stirrer with a shutter and an effective reflux condenser are charged with 63 g of carbon disulfide and 600 ml of water, chlorine is fed at a rate of 0.64 g / min at 15 ° C and vigorous movement. The progress of the reaction is followed by chromatography.

The reaction time is 11 hours. After separation of the acid layer, the reaction mixture contains (wt.%):

Carbon disulfide 9.0

Carbon tetrachloride 8.0 THXXX70.0

Trichloromethane sulfonyl chloride13,0

The TCXXH was isolated from the reaction mixture by distillation and vacuum distillation.

The first fraction, so kin. 46-76 ° C, contains a mixture of unreacted carbon disulfide (54.0%) and carbon tetrachloride (46.0%). The second fraction, distilled at 62-63 ° C / 40 mm, is trichloromethanesulfenyl chloride (99.5%) with carbon tetrachloride (0.5%). 77% yield (on disulfide carbon disulfide). The bottom residue is trichloromethanesulfonyl chloride (96.4%) with an admixture of trichloromethanesulfonic chloride (2.6%) and is 13.35% of the initial weight of the reaction mixture.

Example 2. As in Example 1, 63 g of carbon disulfide and 600 g of 2% sulfuric acid are charged, chlorine is fed at a rate of 0.64 g / min. At 15 ° C, the process takes 8.0 hours. After separation of the acid layer, the reaction mixture contains (wt.%):

Carbon disulfide10,0

Carbon tetrachloride 3,0

THXMSX80.0

Trichloromethanesulfonyl chloride 7, 0

Trichloromethanesulfenyl chloride was isolated as in Example 1. The yield of the target product was 89.0% (per reacted carbon disulfide). The content of trichloromethanesulfonyl chloride is 99.6%.

Example 3. As in example 1, load 63 g of carbon disulfide and 600 g of 40% sulfuric acid, chlorine is fed at a rate of 0.64. At 15 ° C, the process takes 7.0 hours. After separation of the acid layer, the reaction mixture contains (wt.%):

Carbon disulfide

carbon THX Trichloromethanesulfonyl chloride

The isolation of trichloromethanesulfonyl chloride was carried out as in Example 1. The yield of the target product was 93.5% (per reacted carbon disulfide). The content of trichloromethanesulfonyl chloride is 99.7%.

Subject invention

The method of producing trichloromethanesulfonyl chloride by chlorination of carbon disulfide in an aqueous medium, followed by isolation of the target product by known methods, characterized in that, in order to reduce the formation of by-products, the process is carried out in the presence of dilute sulfuric acid.