32 Dr. N. Collie on the Action of Heat on 



of existence : at all events it cannot be obtained by any of the 

 following processes : — 



(1) By the action of barium carbonate on the sulphate. 



(2) By the action of silver carbonate on the chloride. 



(3) By dividing a solution of the hydrate into two portions, 

 and saturating one half with carbon dioxide and then adding 

 the other half to it. 



In each of these cases a strongly alkaline solution was 

 obtained, which, on evaporation to dryness and subsequent 

 heating, invariably decomposed with the greatest ease into 

 the same substances ; viz. toluene, oxide of triethylphosphine, 

 and carbon dioxide. As these substances could not easily be 

 produced from the normal carbonate unless water had acted 

 on the salt, 



((C 2 H 6 ) s (C 7 H 7 )P) 2 C0 3 +H 2 0=2C 7 H 8 +2P(C 2 H 5 ) 3 + CO s , 



several careful experiments were performed in order to 

 ascertain whether this was the case or not. Some more car- 

 bonate was prepared by the last-named method, and the solu- 

 tion was concentrated in vacuo over sulphuric acid, and finally 

 allowed to remain with phosphoric anhydride in a vacuum 

 desiccator for two months. It had then dried up to a mass of 

 brittle white crystals, which remained constant in weight and 

 on analysis gave the following numbers : — 



0-223 grm. salt gave 0532 grm. C0 2 and 0*190 H 2 0. 



Calculated for 



((C, "FT ^ (d H YPl no (C2H 5 ) 3 (O t H 7 )PHC03 -p ■, 



C 67-78 65*32 65-07 



H 9-20 9-27 9-46 



These numbers show that the normal carbonate is not formed 

 by the foregoing process, and that the salt is probably a mix- 

 ture of the acid carbonate with the hydrate ; and this is con- 

 ceivable, as it has been already shown that no carbonate of 

 the tetrabenzylphosphonium exists*. 



The action of heat on the dry salt also points to the same 

 conclusion ; for complete decomposition occurred at a tempe- 

 rature of 130° C, and toluene, oxide of triethylphosphine, and 

 carbon dioxide were the only substances produced. 



(C 2 H 5 ) 3 (C 7 H 7 )PHC0 3 = (C 2 H 6 ) 3 PO + C 7 H 8 + CO,, 

 (C 2 H 6 > 3 (C 7 H 7 )POH = (0 2 H 5 ) 3 PO + C 7 H 8 . 



* Letta and Collie, Trans. Roy. Soc. Edin. vol. xxx. part 1, p. 199. 



