BENZYL PHOSPHINES AND THEIR DERIVATIVES. 597 



phosplionium iodide. Thus, for the above quantities of phosphorus and iodine 24 parts 

 of water are required, and the equivalent quantity of benzyl alcohol (H 2 : C 7 H 8 0) is 

 144 parts. 



Experiment 1. — 30 grms. of the phosphorus mixture were placed in a flask fitted 

 with an upright condenser, and 33 grms. of benzyl alcohol were added. 



The mixture became warm on shaking, but no very energetic reaction occurred until 

 the flask containing it was heated in a paraffin-bath ; then, however, an action began and 

 increased so rapidly as to become explosive, — the mixture being shot out of the con- 

 denser, while dense white vapours were evolved, evidently of iodide of benzyl, from their 

 intolerably irritating effect on the eyes. 



A second experiment, conducted in the same way and with the same quantities, led to 

 precisely similar results. 



What was left of the product from these two experiments consisted of a brownish 

 resinous mass. It was first extracted with ether, which, however, did not dissolve very 

 much, then the residue was boiled with alcohol and a solution obtained which deposited 

 abundance of crystals (A) on cooling. These were filtered off and the mother-liquors 

 concentrated, when a second crystalline product (B) was obtained. 



(A) was recrystallised from spirit. It contained iodine, and when dried became very 

 brown. A determination of iodine gave the following result : — 



0-4863 gave 00488 Agl = 00263 1 = 54 per cent. 



It was evidently an impure product, so it was again dissolved in hot spirit. As the 

 solution cooled, two distinct sets of crystals separated. One had the colour of bichromate 

 of potash, while the other was colourless. 



Eventually it was found that the red crystals were much less soluble in spirit than 

 the colourless ones, and by repeated recrystallisation the latter were separated and 

 obtained of the constant melting point 192° C. (corr.), while (B), when purified, had the 

 same melting point. 



The appearance and melting point led us to believe that the colourless crystals from 

 (A) and (B) were both dibenzyl phosphinic acid, and this belief was strengthened by the 

 fact that they dissolved readily in a solution of caustic baryta. The solution thus 

 obtained was treated with carbonic anhydride (to remove excess of baryta), filtered and 

 evaporated to small bulk. As the solution cooled, colourless plates separated out, which 

 on analysis gave numbers showing that they were by no means pure. 



Analysis. 



0-4156 gave 0-106 BaS0 4 = -06256 Ba = 15'05 per cent. 

 0-3930 lost at 110° C. 00893 H,0 = 2270 „ 



Barium, ..... 

 Water, 



All the impure solid products were united and boiled with solution of caustic baryta 



Obtained. 



Calculated for {(C r H r ) 2 P0 2 } 2 Ba,8H 2 



1505 



17-75 



22-70 



1867 



