64 



Dr. John Stenhouse on the 



[Recess, 



Decomposition of Phenyl-mercaptide of Lead. 

 When dry phenyl-mercaptide of lead is heated to a temperature superior 

 to 280° C. it is decomposed, an oil distils over, and plumbic sulphide is 

 left in the retort. This oil boils constantly at 292°'5 C, and corresponds 

 in all its properties with phemjlic sulphide. By oxidation it yielded a sub- 

 stance crystallizing in oblique prisms, and which was proved to be sulpho- 

 benzolene. The action of heat on the lead mercaptide is therefore as 

 follows : — 



^H,} S = C : H ; } s + Pb2S . 



This decomposition is especially interesting, as it proves the body ob- 

 tained by the destructive distillation of the sulphobenzolates to be the true 

 phenylic sulphide. 



Bisulphide of Phenyl. 

 When the pure mereaptan was mixed with about an equal bulk of con- 

 centrated sulphuric acid, the latter acquired a dirty purple colour, and 

 after the lapse of some time, with occasional agitation, became hot and 

 gave off sulphurous anhydride. When cold the upper layer solidified to a 

 mass of crystals, which, on being separated from the acid, washed with 

 water, and crystallized several times from spirit, gave a white crystalline 

 substance. It was dried in vacuo and analyzed. 



I. *308 grm. substance gave • 745 grm. carbonic anhydride and ■ 1 33 grm. 

 water. 



Theory. I. 



C 6 =72 66-05 65*98 



H 5 = 5 .... 4-59 .... 4-80 

 S =32 .... 29-36 



109 100-00 



The analysis corresponds to the formula C G H 5 S, bisulphide of phenyl. 

 It is insoluble in water, soluble in alcohol, very soluble in ether, benzol, 

 and bisulphide of carbon, melts at 61° C. (Vogt* gives 60° C. as the melt- 

 ing-point of his bisulphide of benzyl). It is again reduced to the mereap- 

 tan by zinc and dilute sulphuric acid, or better, by digestion with hydriodic 

 acid and amorphous phosphorus. 



As but traces of phenyl-mercaptan were obtained on decomposing the 

 sulphobenzolate of sodium in a copper retort, while a considerable por- 

 tion of the distillate consisted of the mereaptan when an iron one was used, 

 I was induced to make some experinents in order to see whether it was the 

 copper which caused this difference. This I ascertained to be the case by 

 distilling sulphobenzolate of sodium mixed with copper cuttings in an iron 

 retort, when the proportion of the mereaptan to the sulphide was compara- 

 tively small, and the surface of the copper was converted into cupric sul- 

 phide. Granulated zinc produced a similar result. 



* Ann. der Chem. und Pharra. vol. cxix. p. 149. 



