BENZYL PHOSPHINES AND THEIR DERIVATIVES. 627 



Zinc Iodide Compound. — Obtained by mixing alcoholic solutions of the two bodies, 

 and separated from the fairly concentrated solution in tufts of colourless plates of char- 

 acteristic form. Formula : 2(C 7 H 7 ) 3 P0 5 ZnI 2 (Letts and Collie). 



Acetyl Chloride Compound (Collie). — Obtained by slowly evaporating a solution of 

 the oxide in glacial acetic acid and chloride of acetyl, as a crystalline compound. 

 Formula: (C 7 H 7 ) 3 PO.(CH 3 .COCl). It is unstable, and is decomposed into its consti- 

 tuents by heat : when treated with boiling water and when mixed with an alkali. 



Sulphur Compound (Letts and Collie). — When the oxide is fused with sulphur a 

 reaction occurs, which apparently varies with the temperature, and with the quantity of 

 sulphur employed. If much sulphur is taken and the mixture heated to a high 

 temperature, sulphuretted hydrogen is evolved, the mass becomes dark coloured and 

 resinous products are formed. But if the proportion of sulphur is low (one molecule of 

 the oxide to two atoms of sulphur), and the temperature kept at 240° C, the sulphur 

 dissolves, no gas is evolved, and the product dissolves completely in a large quantity of 

 boiling alcohol. The solution deposits on cooling long silky needles of a light buff colour 

 of the composition, 5(C 7 H 7 ) 3 PO,S. The melting point was found to be 211°-212° C. 

 (uncorrected). 



Nitro Compound. — Obtained by Collie by dissolving the oxide in cold sulphuric 

 acid, adding excess of nitric acid, and pouring the mixture into water. Prepared by us 

 by dissolving the oxide in cold fuming nitric acid and pouring the solution into water.* 

 White amorphous mass soluble in glacial acetic acid, melting at 100° C, and deflagrating 

 at a higher temperature. Formula : (C 7 H 6 (N0 2 )} 3 PO. It is unchanged when boiled 

 with chromic acid, but is oxidised to para-nitro benzoic acid (and presumably phosphoric 

 acid) when warmed with an akaline solution of permanganate of potash (Collie). 

 Attempts by Dr Collie and ourselves to obtain the corresponding amido body were 

 unsuccessful. 



Sulphonic Acid (Collie). — The oxide, when dissolved in strong sulphuric acid, does 

 not react unless the temperature is raised above 100° C. ; between 150° C. and 170° C, 

 the whole of the oxide is readily converted into a sulphonic acid, (C 7 H 6 S0 3 H) 3 PO. This 

 acid is soluble in water, and can be obtained pure from its barium salt. It is semi- 

 crystalline, and dries to a syrup over sulphuric acid. Monoacid Barium Salt, 

 { (C 7 H 6 S0 3 ) 2 Ba (C 7 H 6 )S0 3 H}PO. — Obtained by neutralising the acid with caustic baryta. 

 Is uncrystallisable. Silver Salt. — White flocculent precipitate. Copper Salt. — Green, 

 and soluble in water. Lead Salt. — Soluble. 



The acid behaves with oxidising agents like the nitro body. 



Action of Fused Caustic Potash on the Oxide. — When the oxide is heated with caustic 



* The discovery of the nitro compound was made independently by Dr Collie and ourselves. 

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



