Tetrethylphosphonium and their Decomposition by Heat. 185 



product was made both (a) before, and (b) after recrystalliza- 

 tion. 



(a) 0*4065 grm. (dried over sulphuric acid) required 14*85 

 cubic centim. decinormal nitrate of silver solution = 0*1886 

 grm. iodine = 46*40 per cent. 



(b) 1*085 grm. (dried at 100° C.) required 39*6 cubic 

 centim. decinormal nitrate of silver solution = 0'5029 grm. of 

 iodine = 46*35 per cent. 



A third quantity of the salt made in a similar manner was 

 also analyzed. 



0*9485 grm. required 34*7 cubic centim. of decinormal 

 nitrate of silver solution = 0*44069 grm. iodine = 46*46 per 

 cent. 



These determinations show that in each case the phospho- 

 nium salt was pure. 



Obtained. 



, A v Calculated for 



1. 2. 3. 4. (C 2 H.) 4 PI. 



46*36 46*40 46*35 46*46 46*35 per cent, iodine. 



As regards the properties of this salt, we have nothing to 

 add to the description given by Hofmann and Cahours *. 



Action of Heat on the Hydrate of Tetrethylphosphonium. 



Hofmann and Cahours f had already studied the behaviour 

 of this compound when heated, and had found that it decom- 

 posed in the following manner : — 



(C 2 H 6 ) 4 POH = (C 2 H 5 ) 3 PO + C 2 H 6 ; 



but as they did not make any exact determination of the 

 quantity of phosphine oxide, nor of the ethane produced, and 

 as we were particularly anxious to ascertain whether the 

 above equation expresses the whole change which occurs, we 

 determined to repeat the experiment. 



10 grms. of pure iodide of tetrethylphosphonium were con- 

 verted into the hydrate by adding excess of oxide of silver to 

 its aqueous solution. The liquid filtered from the resulting 

 iodide of silver was transferred to a distilling flask, connected 

 with an apparatus for collecting gas, and heated. At first no 

 change occurred except simple ebullition ; but when the solu- 

 tion grew concentrated effervescence occurred, and eventually 

 from 780-800 cubic centim. of gas were collected. The 

 temperature of distillation slowly rose to 240-243° C, and 

 the distillate crystallized in the condenser. It was identified 

 as triethylphosphine oxide, both by its boiling-point, appear- 



* Hofmann and Cahours, Annalen, vol. civ. p. 15. 

 t Ibid. 



