574 PROF. LETTS AND MR R. F. BLAKE ON 



forming solid crystalline compounds which are decomposed by water. It forms an 

 amorphous (?) orange-coloured chloroplatinate. 



It probably oxidises in the air, and there is some reason for believing that it then 

 gives rise to an oxide C 14 H 15 PO (see p. 585). It certainly oxidises in contact with warm 

 caustic potash solution and air, the product of its oxidation being then dibenzyl 

 phosphinic acid, C 14 H 15 P0 2 . 



It is readily soluble in ether and benzol, but is sparingly soluble in alcohol. 



Tribenzyl Phosphine. — A solid crystalline substance of high boiling point. Possibly 

 volatile in vacuo without decomposition or with only partial decomposition. It combines 

 with hydracids, forming solid compounds which are decomposed by water. Its chloro- 

 platinate is amorphous and buff- coloured. 



It oxidises in the air and fumes when warmed, spontaneous oxidation occurring very 

 readily, the product being the oxide (C 7 H 7 ) 3 PO. It also combines energetically with 

 sulphur and selenium to give colourless crystalline compounds, which are insoluble or 

 very sparingly soluble in water, alcohol, ether, bisulphide of carbon, and chloroform, but 

 are soluble in boiling glacial acetic acid, from which they may be crystallised. Both 

 compounds decompose on exposure to light, and have the formulae (C 7 H 7 ) 3 S and (C 7 H 7 ) 3 Se, 

 respectively. Tribenzyl phosphine combines energetically with benzyl iodide to give 

 tetrabenzyl phosphoDium iodide. 



We may mention that attempts have been made to obtain tribenzyl phosphine by 

 several other methods, but without success. Among them were — 



(1) The action of chloride of benzyl on phosphide of sodium.* 



(2) The action of benzyl alcohol on phosphonium iodide in a sealed tube. This 

 action has also been studied by LEDERMANN.t Apparently only the phosphonium iodide 

 is produced. 



(3) The action of sodium on a mixture of chloride of phosphorus and benzyl bromide. 

 It was by a corresponding method that Michaelis| obtained triphenyl phosphine. We 

 found that no action occurred. 



(4) The action of sodium on tetrabenzyl phosphonium chloride. § 



(5) The action of heat on chloride of tetrabenzyl phosphonium. || 



Compounds of Tetrabenzyl Phosphonium. 



Salts of tetrabenzyl phosphonium have been obtained by the following methods : — 

 The chloride, (1) by the action of chloride of benzyl on phosphide of sodium (Letts 



and Collie).! The method is an excellent one, being easily carried out, and giving a 



good yield of the compound. 



(2) It is also formed by the action of chloride of benzyl on the primary phosphine 



(p. 573). 



* Letts and Collie, these Transactions, xxx. part 1. t Ledermann, Berichte, xxi. (1888) 405a. 



I Michaelis, Berichte, xv. (1882) 801a. § Letts and Collie, loc. cit. || Letts and Collie, loc. cit. 



1 Letts and Collie, loc. cit., p. 181. 



