BENZYL PHOSPHINES AND THEIR DERIVATIVES. 529 



Phenyl phosphine # and tolyl phosphine t both absorb a molecule of oxygen, and are 

 converted into phosphinous acids, which are monobasic, and therefore probably have the 

 constitution, 



B . 



H AP = 0. 



HCK 



These acids are readily decomposed by heat, giving the primary phosphine, and the 

 corresponding phosphinic acid, 



3BPH 2 2 = BPH 2 + 2RPH,0 3 , 



a reaction analogous to that which gives rise to phosphuretted hydrogen and phosphoric 

 acid when hypophosphorous and phosphorous acids are heated. 



Moslinger (loc. cit.) has in part investigated the products of the spontaneous oxida- 

 tion of octyl phosphine, and believes that it also is converted into a phosphinous acid. 



Submitted to the action of strong nitric acid, many of the primary phosphines (and 

 probably all) absorb three atoms of oxygen, and are converted into phosphinic acids. 

 This has been shown by Hofmann J to be the case in the methyl, ethyl, iso-prop}d, iso- 

 butyl, and iso-amyl series. The phosphinic acids are solid substances, which with the lower 

 members of the fatty series can be distilled unchanged.§ But in some other instances a 

 different reaction occurs: thus phenyl phosphinic || acid, when heated slowly to 200° C, 

 gives a pyro acid, while when rapidly heated to 250° C. it decomposes into benzol and 

 meta-phosphoric acid, 



C 6 H 5 PH 2 3 = C 6 H c +HP0 3 . 



The phosphinic acids are all dibasic, and no doubt have the structure — 



B , 



HO->PO . 

 HCK 



All the primary phosphines have distinct alkaline properties. They combine readily 

 with hydracids, forming crystalline compounds which can as a rule be volatilised (with dis- 

 sociation more or less complete), and which resemble the compounds of phosphuretted 

 hydrogen in other respects, particularly in being instantly decomposed by water with 

 liberation of the phosphine. The hydrochl orates combine with chloride of platinum to 

 give chloroplatinates. The salts of the primary bases with oxyacids have been scarcely at 

 all investigated. 



The action of halogens on mono-phosphines has not been sufficiently investigated. 

 Methyl and ethyl phosphine take fire when they come in contact with chlorine or 

 bromine,! but in other cases the action does not appear to have been studied. 



* Michaelis, Berichte, x. (1877) p. 807. + Michaelis and Panek, Annalen, 212, p. 234. 



J Hofmann, Berichte, v. (1873) p. 110. § Hofmann, Berichte, vi. (1873) p. 303. 



|| Michaelis, Berichte, vii. (1874) p. 1070. IF Hofmann, Berichte, iv. (1871) pp. 433 and 609. 



