BENZYL PHOSPHTNES AND THEIR DERIVATIVES. 599 



liquors and warmed with baryta solution, when most of it dissolved. The solution was 

 mixed with the baryta extracts of the insoluble product (from which B was eventually 

 obtained), and after removing the excess of baryta by a current of carbonic anhydride, 

 the filtered solution was evaporated down, once more filtered from a white insoluble 

 substance which had separated, and then allowed to cool, when a crop of crystals was 

 deposited, consisting of thin plates. These were rapidly washed and dried, first in air 

 and then at 110° C. 



Analysis. 



(1) 21655 gave 07852 BaS0 4 = 046168 Ba = 21-31 per cent. 



(2) 1-6808 „ 06116 „ =035961 „ =2139 



As the salt dissolved in hot alcohol and readily separated as the solution cooled, a 

 quantity was thus recrystallised, the crystals dried as before, and a barium determination 



made — 



(3) 1-6086 gave 05918 BaS0 4 = 0-34796 Ba = 2163 per cent. 



The numbers obtained show that the salt was dibenzyl phosphinate of barium. 



Obta ined. Calculated for {(C 7 H 7 ) 2 P0 2 } 2 Ba 



I. II. III. 



Barium, . . 2131 2139 2163 2184 



On adding hydrochloric acid to its solution dibenzyl phosphinic acid was precipitated 

 in the characteristic form. 



Examination of Product B. — This product consisted of colourless needles. They 

 were thoroughly drained in a filter, washed well with spirit, and a melting-point 

 determination made, which agreed fairly well with that of tribenzyl phosphine oxide. 

 Unfortunately the pure product was accidentally lost, so that no combustion of it was 

 made. For that purpose a product obtained from the mother-liquors was used, which 

 was once recrystallised. 



Analysis. 



MW(! f 10329 C0 2 = 02817 C =799 per cent. 



3526 grms. gave < „ * r 



s 5 I 0-2262 H,0 = 0025133 H= 7-12 „ 



Obtained. 



Calculated for (C 7 H 7 ) 3 PO 



79-90 



78-75 



712 



656 



Carbon, .... 

 Hydrogen, .... 



Although both the carbon and hydrogen were too high, there could be no question 

 regarding the identity of the substance, for it gave all the reactions of tribenzyl 

 phosphine oxide, especially the very characteristic yellow crystalline compound with 

 bromine. Moreover, in other experiments a number of these compounds was obtained 

 and analysed. 



Examination of Product C. — The crystals were colourless, and consisted of tufts of 

 radiating needles. They were readily soluble in water and in alcohol. Their aqueous 

 solution reacted as follows : — With, 



(l) Acetate of lead, an immediate white precipitate. 



VOL. XXXV. PART II. (NO. 15). 5 D 



