BENZYL PHOSPHINES AND THEIR DERIVATIVES. 547 



Analysis of No. 1 Salt. 



0-9037 gave 02839 ZnO = 02278 Zn = 25-20 per cent, 



na M o f 01914 H,0 = 0-02126 H= 3-52 „ 



06028 gave j ^^ ^ = ^^ Q = 33 . 66 ^ 



Obtained. Calculated for C 7 H 7 P0 3 Zn,H,0 

 Zinc, .... 2520 25"70 



Carbon, . . . 3366 3320 



Hydrogen, . . . 3"52 3-55 



Analysis of No. 2 Salt. 



I. 05145 gave 01133 ZnO = 00901 Zn = 17-66 per cent. 

 II. 08757 „ 01946 „ =015616 „ =17-83 „ 



n , 97Q f 02021 H,0 = 0022455 H= 425 „ 



5,173 gave ^^ C 5 2 = -229554 C = 4353 „ 



Obtained. 



, » , Calculated for (C 7 H 7 HPO,).,Zn 



I. II. 



Zinc, . . 1766 17 85 17-33 



Carbon, 4353 44-80 



Hydrogen, 425 4-26 



The experiments described above prove conclusively that when monobenzyl phosphine 

 oxidises spontaneously it gives rise to three different products, namely, phosphoric acid, 

 benzyl phosphinous acid (C 7 H 7 )HoP0 2 , and benzyl phosphinic acid (C 7 H 7 )H 2 P0 3 . With 

 regard to the relative quantities of the three substances, the phosphinous acid is produced 

 in by far the largest proportion, and phosphoric acid in the smallest ; the phosphinous 

 acid is, in fact, the main product of the reaction. It is probable that phosphinous acids 

 are always formed when primary phosphines are spontaneously oxidised. 



H. Kohler and Michaelis* state that phenyl phosphine oxidises almost quantitatively 

 in this manner, para-tolyl phosphine also gives rise to the corresponding phosphinous 

 acid,t and Moslinger J states that octyl phosphine is probably converted into a 

 phosphinous acid by spontaneous oxidation. But, so far as we are aware, no other 

 experiments have been made on this subject, which is one of some interest. 



Action of Bromine on the Product of the Oxidation of the Primary Phosphine. — 

 In some of our earlier experiments, before the nature of the products of the oxidation of 

 the primary phosphine had been ascertained, one of us and W. Wheeler submitted these 

 products to the action of bromine. We found that when bromine was added it was 

 rapidly decolorised and the mixture grew hot, while hydrobromic acid was evolved, 

 and the pungent odour of bromide of benzyl became manifest. Excess of bromine 

 was added, and the mixture allowed to remain undisturbed for some time. A crop of 

 crystals then separated, which dissolved both in water and ether, and were obtained 

 colourless by recrystallisation. These crystals on analysis gave the following results : — 



* Kohler and Michaelis, Berichte, x. (1877) p. 810. 



t Michaelis and Panek, Annalen, 212, p. 234. J Moslinger, Berichte, ix. (1876) p. 1008. 



