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



phosphorus trichloride, and aluminum chloride react spontaneously, the reaction 

 proceeding according to the equation — 



2(CH 3 ) 2 CO + PC1 3 = 2HC1 + (CH 3 - CO - CH 2 ) 2 PC1 . 



By means of these different reactions Michaelis and his pupils have obtained a 

 considerable number of substituted phosphorus-chlorides, among which are — 



Phenyl * phosphorus-chloride by methods 1, 2, and 3. 

 Tolylf „ „ 3 



XylyU 



Ethyl § 

 Propyl § 

 Naphthyl || 

 Ace tony 1 1T 



The substituted chlorides resemble trichloride of phosphorus itself, not only in 



composition, but also in properties. As a rule they are fuming liquids, combining readily 



with chlorine to give solid compounds analogous to pentachloride of phosphorus ; treated 



with water they yield phosphinous acids. Thus phenyl phosphorus chloride gives phenyl 



phosphinous acid — 



(C 6 H 5 )PC1 2 +2H 2 0=(C 6 H 5 )PH 2 2 + 2HC1. 



While the products of addition which they form with chlorine react with water to 



give phosphinic acids — 



(C 6 H 5 )PC1 4 + 3H 2 0=(C 6 H 5 )PH 2 3 +4HC1. 



Having obtained the substituted chlorides, Michaelis sought for some method for con- 

 verting them into the corresponding primary phosphines, but the reduction proved to be 

 more difficult than he anticipated. In his first experiments (with phenyl phosphorus 

 chloride) he endeavoured to accomplish it by means of nascent hydrogen (evolved by the 

 action of hydrochloric acid on zinc dust, and also by that of glacial acetic acid on zinc or 

 on sodium amalgam). In these experiments only a trifling reduction occurred, mere 

 traces of the primary phosphine being formed. 



He next studied the action of hydriodic acid on the chloride, and found that when 

 the gaseous hydracid was passed into the chloride, chlorine was gradually replaced by 

 iodine and the resulting iodide combined with hydriodic acid, thus — 



C 6 H 5 PC1 2 + 3HI = C 6 H 5 PI 2 HI + 2HC1 . 



From this iodide Michaelis obtained phenyl phosphine by a similar reaction to that 

 which gives rise to phosphuretted hydrogen from iodide of phosphorus, only instead of 

 employing water for its decomposition alcohol was used. He gives the following equation 

 as representing the reaction which occurs — 



3C 6 H 5 PI 2 ,HI + 9C 2 H 6 = C 6 H 5 PH 2 + 2C 6 H 5 P0 3 H 2 + 3H 2 + 9C 2 H 5 I . 



In later experiments he abandoned this method and employed a much simpler one, 



* Berichte, vi. (1873) 601 ; viii. (1875) 922 ; xii. (1879) 1009. t Berichte, xiii. (1880) 653. 



X Annalen, 212, pp. 203 and 209. § Ibid., xiii. (1880) 2174. 



|| Berichte, ix. (1876) 1051. H Ibid., xvii. (1884) 1273. 



