BENZYL PHOSPHINES AND THEIR DERIVATIVES. 595 



namely, the destructive distillation of the phosphinous acid (which, as already stated, is pro- 

 duced by the action of water or alcohol on the substituted chloride # ). The phosphinous 

 acid decomposes in an analogous manner to phosphorous acid when heated, the products 

 of the reaction being the corresponding phosphinic acid and the primary phosphine — 



3C 6 H 5 P0 2 H 2 =C 6 H 5 PH 2 +2C 6 H 5 P0 3 H 2 . 



The following details illustrate the application of this method to the preparation of 

 phenyl phosphine : — 



100 grms. of the crude phenyl phosphorus chloride are gradually mixed with excess 

 of alcohol and the mixture filtered. The excess of alcohol, &c, is then distilled off in a 

 current of carbonic anhydride and the syrupy residue placed in a distilling flask (through 

 which a current of carbonic anhydride is passed), and heated over the naked flame. At 

 first a little alcohol distils, then at 250° phenyl phosphine passes over. The flame may 

 be removed when once the reaction has commenced, as it continues by itself. 14 grms. 

 of the pure phosphine, or 60 per cent, of the theoretical yield, may be thus obtained. 



From phenyl phosphorus chloride Michaelis obtained diphenyl phosphine by the 

 following reactions : — 



(1) The chloride is digested with mercury diphenyl at 200°, when diphenyl phos- 

 phorus chloride results t — 



(C 6 H 5 )PCl 2 +Hg(C 6 H 5 ) 2 = (C 6 H 5 ) 2 PCl+HgCl(C 6 H 5 ); 



or it is heated for some time at a temperature of 280° C, when the following reaction 



occurs — 



2(C 6 H 5 )PCl 2 = (C fi H 5 ) 2 PCl+PCl 3 . 



(2) Diphenyl phosphorus chloride, when heated with water or dilute soda solutioD, 

 decomposes in the following manner : J — 



2(C 6 H 5 ) 2 PCl-f2H 2 = (C 6 H 5 ) 2 PH + (C 6 H 5 ) 2 HP0 2 +2HCl. 

 He also obtained the tertiary base : at first by acting upon a mixture of phenyl phos- 

 phorus chloride and bromide of phenyl with sodium § — 



(C 6 H 5 )PC1 2 + 2(C 6 H 5 )Br + 3Na = 2NaCl + NaBr + ( C 6 H 5 ) 3 P ; 

 but later this method was modified in a remarkable manner by substituting for phenyl 

 phosphorus chloride, phosphorus chloride alone, the reaction occurring quite easily and 

 very energetically at ordinary temperatures, according to the equation — 



PCl 3 +3(C 6 H 5 )Br+6Na = 3NaCl + 3NaBr+(C 6 H 5 ) 3 P. 



* By modifying the conditions of the experiment a totally different reaction may be made to occur. The 

 phosphinous acid is obtained by adding the chloride to excess of water ; whereas by employing an insufficient quantity, 

 there are produced in addition phenyl phosphinic acid, diphenyl phosphinic acid, and a solid compound of phenyl, 

 hydrogen, and phosphorus, (C 6 H S )HP 4 (phenylated solid phosphide of hydrogen). Michaelis gives the following 

 equations : — 



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



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



(3) 5(C 6 H 5 )PO=(C 6 H 4 ) 4 P 2 3 + P 2 +C 6 H 5 P0 2 . 



(4) 5(C 6 H 5 )PO+H 2 0+3P 2 =2(C 6 H 5 )P 4 H+3C 6 H 5 P0 2 = 2(C 6 H 6 ) 2 P 6 2 H + C 6 H 5 P0 2 . 



t Berichte, viii. 1304. J Michaelis and Gleichmann, Berichte, xv. (1882) p. 801. 



§ Michaelis and Gleichmann, Ibid., p. 820. 



