

T)48 PROF. LETTS AND MR R. F. BLAKE ON 



Analysis. 



0221 gave 0166 AgBr = 07065 Br = 3L9 per cent. 



noszL f 06245 C0 o =0-18735 C =489 



U ZV* gave ( 01535 u ^ =0 . 01705 H = 8 . 9 () 



Obtained. Calculated for (C 7 H 7 ) 3 P 2 Br 2 H 3 

 Carbon, . . . 489 490 



Hydrogen, . . . 4 - 9 4'7 



Bromine, . . . 319 311 



In another experiment, conducted in a similar manner, we also obtained a solid 



crystalline substance, which, after crystallisation from water, consisted of scales with 



mother-o'-pearl lustre, and a melting point of 176° C. A bromine determination gave the 



following result : — 



02423 gave 0176 AgBr = 0849 Br = 309 per cent. 



In a third experiment completely different results were obtained. In this experiment 

 a quantity of the primary phosphine, which had been kept for some years in a loosely- 

 corked flask, was treated with bromine, when, as in previous experiments, abundance of 

 hydrobromic acid was evolved, and the mixture grew very hot. The product was heated 

 for a considerable time on a water-bath to get rid of hydrobromic acid. The residue 

 had an intolerable odour of bromide of benzyl. On treatment with water some of it 

 dissolved, but an oily liquid remained, which solidified on cooling. The aqueous solution 

 gave the reactions of benzyl phosphinic acid. The oily liquid had acid properties. It 

 was dissolved in baryta water, the solution filtered, and precipitated by hydrochloric acid. 

 The resulting crystalline precipitate was recrystallised from hot alcohol, in which it readily 

 dissolved. Its corrected melting point was now found to be 176° C. Its analysis gave 

 the following results : — 



Analysis. 



( 03920 C0 2 = 0T06909 C = 6397 per cent. 

 ■] 0-1014 H 2 6 =0011266 H= 674 

 1 00732 Mg,P 2 7 = 0-020443 P = 1223 



Obtained. Calculated for C^li^PjOj 

 Carbon, .... 63-97 6393 



Hydrogen, . . . 674 6"96 



Phosphorus, . . . 12-23 1270 



A quantity was converted into its barium salt, and the latter analysed. 



Analysis. 



0-3214 i lost at l10 ' °' 0328 = 10 " 20 P er cent - H 2° 



t gave OT072 BaSO 4 = 0063031 Ba = 19-61 per cent. Ba 



Obtained. Calculated for C 6 H 32 P 2 6 Ba,4H 2 



Barium, .... 1961 1971 



Water, .... 1020 1036 



As we found that benzyl phosphinic acid is not attacked by bromine at ordinary 

 temperatures, the substances which we obtained by the action of bromine on the oxidised 

 phosphine are probably formed from benzyl phosphinous acid. 



