RU2694905C1 - Method of producing thiophosgen - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing thiophosgene, which can be used in chemical industry. Disclosed method of producing thiophosgene from a compound containing a S-trichloromethyl group is characterized by the fact that the desired compound is obtained from trichloromethylbenzyl sulphide reacting with phosphoric anhydride at temperature of 160 °C to 180 °C.

EFFECT: novel efficient method of producing thiophosgene with high output and purity using less toxic trichloromethylbenzyl sulphide and shorter duration of the process.

1 cl, 1 ex, 2 dwg

Description

The invention relates to the field of organic chemistry, in particular to a method for producing thiophosgene.

Thiophosgene is used in the practice of organic synthesis to obtain symmetric and asymmetric thioketones, halogen derivatives of thiocarboxylic acids, thiourea, various isothiocyanates, and compounds of the 2-thiabicycloheptane series [1].

The known method [2] in which thiophosgene is obtained by the interaction of trichloromethylsulfenyl chloride with tetralin at a temperature of from 195 ° C to 200 ° C according to scheme 1:

The disadvantage of this method is obtaining the target compound from hard-to-reach toxic trichloromethylsulfenyl chloride and carrying out the reaction at a high temperature for 22 hours.

A method [3] is described in which thiophosgene is obtained by decomposing trichloromethylsulfenyl chloride in an acidic aqueous medium in the presence of iodine according to scheme 2:

The disadvantage of this method is the use of gaseous sulfur dioxide, when working with which requires the use of appropriate equipment and additional security measures.

Known methods for producing thiophosgene [4-6], in which the target compound is obtained by the interaction of trichloromethylsulfenyl chloride with hydrogen sulfide gas. The reaction proceeds according to scheme 3 at a temperature of from 120 ° C to 180 ° C in a flow tube reactor filled with silica gel or an anhydrous catalyst for which the chlorides or sulfides of metals are used.

The disadvantages of the above methods are the use of toxic hydrogen sulfide gas, a glass tube reactor with a complex system of temperature control and supply of reagents, and the need for an additional stage of preparation of the catalysts.

Also, thiophosgene is obtained [7] by reacting trichloromethylsulfenyl chloride with white phosphorus in a nitrogen atmosphere at a temperature of 130 ° C according to Scheme 4:

The main disadvantage of the above method is the use of highly toxic white phosphorus that self-ignites in air, which requires compliance with additional conditions and safety measures during the synthesis.

The known method [8] of obtaining thiophosgene by reacting trichloromethylsulfenyl chloride with symmetric or asymmetric dialkyl sulfides in an inert high boiling solvent in the presence of iodine or iron trichloride in catalytic amounts, followed by distillation purification of a technical product. The method is implemented according to scheme 5:

The disadvantages of this method is the need for distillation purification of the target compounds for which the presence of appropriate equipment.

A method [9] is described in which thiophosgene is obtained by reacting trichloromethylsulfenyl chloride with aromatic compounds in the presence of Lewis acids, presented in Scheme 6:

The disadvantage of this method is the duration of the process, which is not less than 16 hours and the need for distillation purification of the target thiophosgene.

A common disadvantage of the above methods is the preparation of thiophosgene from commercially unavailable and toxic trichloromethylsulfenyl chloride.

Closest to the claimed, is the method [10] of obtaining thiophosgene, based on the decomposition of S-trichloromethyl benzenesulfonic acid at a temperature of about 250 ° C, proceeding according to scheme 7:

Thiophosgene is prepared as follows. The starting S-trichloromethyl benzenesulfonic acid is obtained from sodium benzyl sulfinate and trichloromethyl sulfenyl chloride. And then carry out its decomposition within 2.5 hours under the influence of high temperatures.

Commercial unavailability of the original S-trichloromethyl benzenesulfonic acid and the long stage of its decomposition at a temperature of about 250 ° C are a significant drawback of the method.

The present invention is to obtain thiophosgene from the available [11], less toxic reagents with less time spent.

The problem is solved due to the fact that thiophosgene is obtained from a compound containing S-trichloromethyl group according to the invention, the target compound is obtained from trichloromethylbenzyl sulfide, interacting with phosphoric anhydride at a temperature of from 160 ° C to 180 ° C.

The technical result achieved in the claimed invention is expressed in the reduction of the total duration of the process to 30 minutes and the preparation of thiophosgene from the less toxic trichloromethyl benzyl sulfide available without the use of sophisticated laboratory equipment.

The difference of the proposed method is that the target thiophosgene is obtained by decomposition of trichloromethyl benzyl sulfide with phosphoric anhydride at a temperature of from 160 ° C to 180 ° C. The process takes place within 30 minutes using standard laboratory equipment and available reagents that do not require additional conditions and safety measures when working with them.

The chemical essence of the proposed method is presented in figure 8:

The purity and structure of the obtained target compound was confirmed by gas chromatography-mass spectrometry.

The chromatogram of the sample of the synthesized compound by the total ion current and the mass spectrum of the target thiophosgene are presented in the figures (Fig. 1 and Fig. 2, respectively).

For a better understanding of the essence of this invention, the following example is provided.

Example.

9.0 g (0.037 mol) of trichloromethylbenzyl sulfide and 10.5 g (0.074 mol) of phosphoric anhydride are placed in a 50 ml flask equipped with a reflux condenser (h≈200 mm), a Wurtz nozzle with a thermometer and a direct refrigerator. The reaction mass is stirred and heated in a bath with a temperature of from 160 ° C to 180 ° C for 30 minutes, at the same time collecting the fraction boiling in the temperature range from 72 ° C to 80 ° C. Obtain 3.0 g of thiophosgene in the form of a mobile liquid of orange-red color with a yield of 70% of theoretical and purity of at least 90%.

Literature

1 Sharma S. Thiophosgene in organic synthesis // Synthesis. - 1978. - №11. - P. 803-820.

2 Verfahren zur Herstellung von Thiophosgen: Pat. 853162 Bundesrepub-lic Deutschland; declare 02/07/1952; publ. 08.21.1952. - 2 s.

thiofosgenu z perchlormethylmerkaptanu: пат. 103963

republika; заявл. 15.12.1961; опубл. 15.06.1962.-3 с.3

thiofosgenu z perchlormethylmerkaptanu: Pat. 103963

republika; declare 12/15/1961; publ. 06/15/1962.-3 p.

4 Process for the production of thiophosgene: Pat. 3,979,451 USA; declare 05.22.1974; publ. 09/07/1976. - 4 s.

5 Process for the production of thiophosgene: Pat. 3,776,954 USA; declare 06.24.1972; publ. 12/04/1973. - 4 s.

6 Process for the production of thiophosgene: Pat. 3,699161 USA; declare 04/15/1971; publ. 10/17/1972. - 4 s.

7 Manufacture of thiophosgene and alpha-halosulfides: Pat. 2,861,103 USA; declare 01/11/1957; publ. 11/18/1958. - 2 s.

8 Thiophosgene: Pat. 3150176 USA; declare 05/29/1961; publ. 09/22/1964. - 4 s.

9 Production of thiophosgene: Pat. 2668853 USA; declare 10/12/1950; publ. 02/09/1972. - 6 c.

10 Verfahren zur Herstellung von Thiocarbonyldihalogeniden: Pat. 1219455 Bundesrepublic Deutschland; declare 06/23/1966; publ. 01/12/1967. - 1 s.

11 E. Demlov, Z. Demlov. Interphase catalysis. - M .: Mir. - 1987. - 466 s.

Claims (1)

A method of producing thiophosgene from a compound containing an S-trichloromethyl group, characterized in that the target compound is obtained from trichloromethylbenzyl sulfide, which interacts with phosphoric anhydride at a temperature of from 160 ° C to 180 ° C.

Images