Antimony monochloride trichloride

In a batch process (176), a glass-lined jacketed iron vessel is charged with either sulfur monochloride or sulfur dichloride and about 1% of antimony trichloride as a catalyst. Chlorine is introduced into the reactor near the bottom. Liquid oleum is added to the reactor at such a rate that the temperature of the reaction mass is held at ca 25°C by the use of cooling water in the jacket. 

Synthesis of sulfur tetrafluoride by fluorination of sulfur monochloride with elemental fluorine in the presence of antimony(III) chloride or phosphorus trichloride as a catalyst has also been reported 22-23 sulfur dichloride, which is formed as the byproduct, is converted back to sulfur monochloride in an absorber filled with granulated sulfur and then recycled. 

It is convenient, however, to use the commoner monochloride, with which a similar reaction readily occurs at 75° to 80° C. the sulphur produced can be reconverted continuously into monochloride by means of a current of chlorine, and the formation of the thionyl chloride can be assisted by the addition of suitable catalysts, such as antimony trichloride or mercuric chloride. 

---