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



Berle next attempted * to prepare the tertiary phosphine by heating sodium, phos- 

 phorus, and iodide of ethyl together in a sealed tube, but although a reaction occurred, he 

 does not appear to have obtained any very satisfactory results. 



CAHOURst in 1859 prepared iodide of tetrethyl phosphonium by the action of iodide 

 of ethyl on crystallised phosphide of zinc (obtained by heating the metal in phosphorus 

 vapour at 180° C). 



In 1882 one of us and N. Collie X investigated the action of benzyl chloride on phos- 

 phide of sodium. The latter substance was obtained with perfect ease and safety by 

 acting upon sodium with phosphorus under the surface of dry xylol. The two bodies 

 (chloride of benzyl and the metallic phosphide) react readily when they are heated 

 together, and chloride of tetrabenzyl phosphonium is produced in abundance. Experiments 

 were also commenced with the haloid derivatives of some other hydrocarbons, but were 

 not completed. The results obtained were on the whole satisfactory, and no doubt this 

 method for producing tertiary and quaternary phosphorus derivatives will find a more 

 extended application in the future. 



(2) Action of Organo-Metallic Bodies on Trichloride of Phosphorus. — The action of 

 zinc alkyls on trichloride of phosphorus was first investigated by Hofmann and 

 Cahours,§ and was further studied by Hofmann alone. || It is in a sense the 

 reverse of the action of a metallic phosphide on a haloid ether, but resembles it in 

 that the action in both cases is determined by the attraction of halogen for metal. By 

 this method tertiary phosphines are exclusively formed — 



3R 2 Zn + 2PCl 3 =2R 3 P + 3ZnCl 2 . 



It is necessary to treat the product of the reaction with caustic potash, in order to 

 decompose the compound of phosphine and chloride of zinc and to liberate the former. 

 By its means Hofmann and Cahours obtained trimethyl and triethyl phosphine, and 

 submitted them to an exhaustive examination. They showed that tertiary phosphines 

 resemble the corresponding amines in many respects, especially in the readiness with 

 which they combine with the iodides of hydrocarbon radicals to give quaternary com- 

 pounds. On the other hand, they proved that, unlike the amines, tertiary phosphines 

 readily combine with oxygen to give very stable compounds of the general formula R 3 PO. 



(3) Action of Alcohols on Phosphonium Iodide; and (4) Action of Alky I Iodides on 

 Phosphonium Iodide and Oxide of Zinc (Hofmann's methods). — In the year 1871, 

 seventeen years after his experiments with Cahours, Hofmann again took up 

 the study of the phosphines, and succeeded in discovering a simple method not only for 

 obtaining the tertiary and quaternary compounds, but also the primary and secondary 

 bases, — substances which had not been previously obtained, and whose investigation 



* Berle, Comp. Rend., xlix. 



t Cahours, Comp. Rend., xlix. p. 87 ; and Jahresbericht, 1859, p. 430. 



I Letts and Collie, these Transactions, xxx. part 1, p. 181. 



§ Hofmann and Cahours, Ann. de Chirn. et de Phys. (3), li. 



|| Hofmann, Ibid., lxii., lxiii., lxiv. 



