the Salts of Triethylbenzylplwsphonium. 33 



No ketone could be detected, and the gas evolved was com- 

 pletely absorbed by caustic soda. 



Many other experiments were made with carbonate pre- 

 pared by the other methods mentioned, but always with the 

 same results. 



Acid Carbonate of Triethylbenzylphosphonium. 



This salt can be easily prepared by saturating a solution of 

 the hydrate with carbon-dioxide gas ; the solution is faintly 

 alkaline to litmus-paper, and can be evaporated over the 

 water-bath without decomposition ; but to be obtained in the 

 crystalline state it must be allowed to remain in vacuo with 

 sulphuric acid for a considerable time. 



0-312 grm. of salt gave 0*705 C0 2 and 0*249 H 2 0. 



Calculated for ^ -, 



(C 2 H 5 ) 3 (0 7 H 7 )PHC0 3 . ■ bound - 



C 62-22 61-62 



H 8-51 8S6 



This salt decomposes completely, when heated to 130° C, 

 into toluene, carbon dioxide, and oxide of triethylphosphine. 

 10 grams of the dry salt gave 800 cubic centim. of carbon- 

 dioxide gas, which was completely absorbed by caustic soda. 

 The theoretical amount required by the following equation 

 is 827 cubic centim. 



(C 2 H 5 ) 3 P^ i , = (C 2 H 5 ) 3 PO + C 7 H 8 + C0 2 ; 



\H-co 2 ;h 



thus showing that the decomposition was complete. 



The extreme ease with which this acid carbonate decom- 

 poses, and the apparent non-existence of the normal salt, 

 show a very marked diminution in the alkalinity of the 

 hydrate of triethylbenzylphosphonium as compared with the 

 hydrate of tetrethylphosphonium. The normal carbonate of 

 the latter is a stable substance, but the introduction of the 

 benzyl group into the molecule in the place of an ethyl group 

 seems sufficient to make a considerable difference ; while, if 

 all the ethyl groups be replaced by benzyl groups, as in the 

 hydrate of tetrabenzylphosphoninm, the alkalinity of the 

 hydrate becomes so feeble that it is no longer capable of 

 fixing carbon dioxide at all. 



Sulphate of Triethylbenzylphosphonium. 



This salt was prepared by the action of sulphate of silver 

 on the chloride ; the small quantity of dissolved sulphate of 

 Phil. Mag. S. 5. Vol. 24. No. 146. July 1887. D 



