the Salts of Triethylbenzylplwsplwnium. 35 



The decomposition which the sulphate undergoes when 

 heated is therefore probably as follows : — 



/C 7 H 7 

 (C 2 H 5 ) 3 P(^ : 



H 

 !>S0 2 = 2(C 2 H 5 ) 3 PO + C 14 H u +S0 2 ; 



M 



(c 2 h 5 ) 3 p<;, i 



x ;c 7 h 7 



and differs from the action of heat on the sulphate of tetrethyl- 

 phosphonium, as no sulphide of a tertiary phosphine is formed. 

 The toluene and stilbene noticed are no doubt produced by 

 the decomposition of the dibenzyl, 



2C 14 H 14 = C 14 H 12 + 2C 7 H 8 . 



This decomposition has already been noticed, when the chloride 

 of tetrabenzylphosphonium is decomposed by heat*. 



Acetate of Trietliylbenzylphosphonium. 



In order to prepare this salt, barium acetate was added 

 carefully to a solution of the sulphate in water. During the 

 concentration of the aqueous solution over the water-bath, a 

 smell of diethylbenzylphosphine was noticed. The acetate 

 is extremely deliquescent and difficult to obtain in the crys- 

 talline state. When it was heated, no change occurred till 

 the salt had reached a temperature of 200° C. ; decomposition 

 then began rapidly, and liquid distilled, but no gases were 

 evolved, and towards the end of the experiment the contents 

 of the flask had to be heated to a temperature above 300° 0. 

 On washing out the distillate from the condenser with a little 

 water, it separated into two layers, the upper one being 

 insoluble in water. The aqueous solution was acid in its 

 reaction with litmus-paper, and gave with caustic soda a 

 trace of free triethylphosphine ; on distillation it seemed to 

 be almost completely composed of water and oxide of triethyl- 

 phosphine ; there was mixed with it, however, a small quantity 

 of some substance which possessed a very high boiling-point, 

 and yielded some triethylphosphine when again distilled. 



The liquid, insoluble in the water, contained no free 

 phosphine, and, on being subjected to fractional distillation, 

 yielded first a little toluene, but consisted almost entirely of 



* Letts and Collie, loc. cit. p. 213. 



D2 



