BENZYL PHOSPHINES AND THEIR DERIVATIVES. 617 



Sodium Benzyl Phosphinate and Ammonium Benzyl Phosphinate resemble the 

 potassium compound, and were prepared in a similar manner. They were not analysed. 



Action of a Moderate Heat on Benzyl Phosphinic Acid. — When moderately heated 

 the acid loses water, the amount finally lost varying apparently with the conditions of 

 the experiment. In one experiment about five grms. of the acid* were placed in a 

 distilling flask, through which a slow current of hydrogen passed, and the flask was 

 heated in an oil-bath for some hours at a temperature ranging from 180°-195° C, then 

 to 220°-230° C. for nearly a week. During this time a trace of the acid or some product 

 of its decomposition appeared to volatilise. At the end of this time the loss amounted 

 to 4*19 per cent. The equation — 



2C 7 H 7 H 2 P0 3 = H 2 + (C 7 H 7 ) 2 H 2 P 2 5 



requiring 5 '23 per cent. The product was light brown in colour, and very crystalline. 

 On boiling with water it appeared to be quite insoluble. A little of it, mixed with a 

 solution of caustic baryta, gave at once a crystalline deposit, which seemed to be very 

 insoluble. The whole of the product was pounded in a mortar and boiled with water, 

 in which some, but not all dissolved. The solution, which was fairly dilute, was then 

 mixed with a slight excess of caustic baryta and gradually heated. Long slender 

 needles separated, which were well washed and air dried. 



Analysis. 



1-2391 lost at 240° C. 01173 = 9-46 per cent. 



1-2391 gave 0-5733 BaS0 4 = 0-337 Ba = 27-19 

 06822 „ 08146 CO 2 = 0'222163 0=32-56 

 06822 „ 0-2363 H 2 = 0-026255 H= 384 



Water, ..... 

 Barium, ..... 

 Carbon, ..... 

 Hydrogen, ..... 



In another experiment about 5 grms. of the acidt were heated at once to 230° C, 

 and kept at that temperature for a considerable time. The final loss amounted to 14 '4 4 

 per cent. The equation — 



2(C 7 H 7 )H 2 P0 3 ,H 2 = 3H 2 + (C 7 H 7 ) 2 H 2 P 2 5 



requires a loss of 14*21 per cent. 



It would appear from this result that the two specimens of acid experimented with 

 were different, the latter containing water of crystallisation, the former none. The 

 product from this second experiment was broken up, pounded fine, and boiled with water, 

 in which it ultimately dissolved. The solution was divided into three parts, A, B, and C. 



* Not absolutely pure, but recrystallised two or three times from the crude product. 



t A very pure specimen of the acid, which had been obtained from the barium salt, and was snow-white. 



Obtained. 



Calculated for (C 7 H 7 ) 2 P 2 5 Ba,3H 2 



9-46 



10-48 



2719 



26-60 



32-56 



32-62 



3-84 



3-88 



