Tetrethylphosphonium and their Decomposition by Heat. 205 



pose to any extent till the temperature has risen ahove 300° C; 

 it then slowly chars, yielding gases and sulphide of triethyl- 

 phosphine. 



The nitrate of tetrethylphosphonium, when evaporated in 

 vacuo over sulphuric acid, is deposited from its solution in 

 deliquescent needle-shaped crystals. These, when heated, 

 suddenly puff, yielding large quantities of gases and some 

 oxide of triethylphosphine. 



Conclusion. 



From the foregoing experiments it appears that the salts of 

 tetrethylphosphonium with organic oxyacids suffer, as a rule, 

 at least two, and occasionally three, different and distinct 

 changes under the influence of heat. 



In one of these the molecule splits up into three new groups, 

 consisting respectively of carbonic anhydride, a paraffin 

 hydrocarbon, and a tertiary phosphine. In another, two 

 hydrocarbons are formed, namely, an olefine and a paraffin, in 

 addition to carbonic anhydride and the tertiary phosphine. 

 Whilst in the third, a totally different change occurs, in which 

 only two products are formed, namely, the oxide of the tertiary 

 phosphine and a ketone. 



(1) Et 3 P<^E=Et 3 P + C0 2 + C 2 H 5 K 



(2) Et 3 P<g^|^Et 3 P + CO,-hC 2 H 4 + EH. 



(3) Et 3 P<^ R=E t 3 PO + C 2 H 5 .CO.K. 



It is possible, if not indeed probable, that the third reaction 

 occurs subsequently to the first, and that it really depends 

 upon the reducing action of the triethylphosphine upon the 

 carbonic anhydride, at the high temperature at which the de- 

 composition usually occurs, whereby carbonic oxide is liberated, 

 which combines with the hydrocarbon radicals in statu nas- 

 cendi, forming a ketone : — 



Et 3 + P + C0 2 + (Et) + (R) = Et 3 PO + EtCOR 

 (or Er 3 P + (OCO-E) + (Et) =Et 3 PO + Et CO R). 



If we merely consider the third kind of decomposition 

 alone, it appears to be, to a certain extent, analogous to the 

 decomposition which a sulphine compound suffers when 

 heated, the difference depending on the far more powerful 

 attraction which phosphorus has for oxygen, than sulphur has 

 for the same element. In both cases a hydrocarbon group is 



