BENZYL PHOSPHINES AND THEIR DERIVATIVES. 539 



and phosphoric acids. In addition to the above, Michaelis * obtained a phenylated solid 

 phosphide of hydrogen, (C 6 H 5 )HP 4 , by treating phenyl phosphorous chloride with a quantity 

 of water insufficient for complete decomposition (for instance, by keeping it in a badly- 

 stoppered bottle). It is a dark yellow amorphous body, having a faint odour of phenyl 

 phosphine, soluble in hot bisulphide of carbon, but insoluble in water, alcohol, and ether. 

 Treated with chlorine, it reacts as follows : — 



(C 6 H 5 )HP 4 + 6C1 2 = 3PC1 3 + (C 6 H 5 )PC1 2 + HC1 . 



Nitric acid oxidises it to a mixture of phenyl phosphinic and phosphoric acids. 



The action of phosphonium iodide on aldehydes has been studied by GiRARD,t while 

 that of phosphuretted hydrogen and hydrochloric acid on the same bodies and on ketonic 

 acids has been investigated by Messinger and Engels. J Girard obtained products of 

 addition containing four molecules of the aldehyde (valeric, propionic, salicylic, and benzoic) 

 to one of phosphonium iodide. 



Messinger and Engels obtained similar bodies by acting upon the aldehydes with 

 hydrochloric acid and phosphuretted hydrogen. The compounds thus formed are for the 

 greater part solid, crystalline, and fairly stable. By treatment with water, they are 

 decomposed, and the aqueous solution gives the reactions of hydrochloric acid and 

 phosphuretted hydrogen. Their constitution is probably represented by the formula 

 (R-CHOH) 4 PCl. Chloride of tetra-hydroxyethylidene phosphine (C 2 H 5 0) 4 PC1, is 

 decomposed by caustic potash into the free phosphine (C 2 H 5 0) 3 PC 2 H 4 0, and the hydrate 

 (C 2 H 6 0) 4 P(OH). Benzaldehyde and its mono-nitro derivative give compounds which 

 differ from those obtained in the fatty series, in that they contain no hydracid. 



Messinger and Engels have summarised the result of their researches as follows : — 

 (1) Phosphuretted hydrogen does not act on an aldehyde alone, but is absorbed if at the 

 same time a hydracid is present. The absorption occurs more completely if the aldehyde 

 is largely diluted with ether. (2) The aldehydes of the fatty series combine with a molecule 

 of phosphuretted hydrogen and a molecule of hydracid, while those of the aromatic series 

 combine with phosphuretted hydrogen only, though in order that the compound shall be 

 formed the presence of the hydracid is necessary. (With benzoic aldehyde the compound 

 has the formula (C 6 H 5 COH) 4 PH 3 ). (3) The phosphorised derivatives of the fatty 

 series have an unpleasant smell, and are decomposed by water, while those of the 

 aromatic series have no odour, and are nearly insoluble in water. All are soluble with 

 difficulty in ether, and in some cases insoluble. 



By the substitution of a ketonic acid for an aldehyde in the above reaction, com- 

 pounds are produced in certain cases. Thus lsevulinic acid gives an oil and pyruvic acid 

 a solid compound either — 





 (CH 3 - CO - CO') 3 P or(CH 3 - (Cb = o) 3 P , 



* Michaelis, Berichte, xi. (1878) p. 885. 



t Girard, Ann. de Chim. und de Phys. [vii.], ii. p. 50. 



% Messinger and Engels, Berichte, xxi. (1888) p. 328a and p. 2919a. 



