BENZYL PHOSPHINES AND THEIR DERIVATIVES. 579 



phine. The baryta extracts filtered off were mixed with those which had been employed in 

 extracting the resin which was insoluble in alcohol, and the mixture deposited on cooling 

 a small quantity of oxide of tribenzyl phosphine. This was filtered off, and excess of 

 baryta removed from the solution by a current of carbonic anhydride. The filtered 

 solution gave on concentration a considerable quantity of '''crystalline oil," which was 

 filtered off. To the filtrate from this, hydrochloric acid was added, when an oily liquid 

 was precipitated which rapidly solidified to a crystalline mass. The latter was recrys- 

 tallised from alcohol, and was identified by its melting point (190° corr.), appearance, and 

 by an analysis of its barium salt as dibenzyl phosphinic acid. 



Analysis of Barium Salt. 



Obtained. Calculated for {(C 7 H 7 ) 2 P0 2 } 2 Ba,8H 2 



Barium, . . . 16-99 1777 



Water, . . . 1858 1867 



The mother-liquors from which the acid had been separated by hydrochloric acid were 

 mixed with sulphuric acid, filtered from the precipitated sulphate of barium, and evaporated 

 on a water-bath until all hydrochloric and hydriodic acid had volatilised. The residue was 

 diluted, neutralised with chalk, filtered and evaporated to small bulk, when a sparingly 

 soluble calcium salt separated in crystalline crusts. These, after being washed first with 

 water and then with spirit, were dried at 110° and a determination of calcium made. 



Analysis. 



Obtained. Calculated for {(C 7 H r )HP0 2 } 2 Ca 



Calcium, .... 1108 11-42 



The properties of the acid from which the calcium salt was prepared, such as the 

 production of the primary phosphine on heating, and the characteristic reaction with a 

 copper salt, further identified it as benzyl phosphinous acid. 



D. A Crystalline Substance of low Melting Point (" Crystalline Oil "). — This 

 substance was contained in the viscous mass which remained after treating the product 

 of the sealed tube reaction with aqueous caustic potash, or, if alcoholic potash is employed, 

 it passes into solution. 



It dissolved sparingly in water, and separated out from a hot solution in oily drops, 

 which eventually solidified. 



It was produced in only small quantity — the largest amount which we have ever 

 obtained being about 9 grms. from the contents of twenty-four tubes, representing 

 288 grms. of chloride of benzyl. 



The investigation of this substance has given us a great deal of trouble, and we are 

 still uncertain as to its composition. The following analyses were made by one of us and 

 W. Wheeler : # — 



(I.) Crude substance washed with ether. 



0-2741 i °' 6922 C0 2 = 018879 C =68-88 per cent. 



gaVG (01650 H 2 = 001833 H= 6-68 



* Proceedings, 1887, p. 82. 



