BENZYL PHOSPHLNES AND THEIR DERIVATIVES. 541 



mixture at a temperature of 120° C. Experiments tried at 100° to 110° C. showed that 

 but little of the primary phosphine is formed. 



With the quantities Hofmann recommends and a digestion for six hours at 120°, the 

 tubes when cold contain a viscous semitransparent mass, sometimes of a brown colour 

 sometimes red and opaque from the separation of free phosphorus. Above this a small 

 quantity of a liquid usually floats, which at times is mobile, but at others thick and 

 slightly fluorescent. A few crystals of undecomposed iodide of phosphonium are also 

 frequently present. If pure chloride of benzyl is used there is usually no liquid floating 

 on the surface of the product. 



After opening the tubes, their contents were transferred to a flask, and submitted 

 to the action of steam and water by means of the apparatus shown in figure 1 of the 

 Plate. 



A is a wide-mouthed flask provided with a large cork, with a large and somewhat 

 conical hole, through which the inverted tube B passes. 



C is a bent tube, which can be raised or lowered at will according to the length of B, 

 so that its upper extremity may be near the closed end (of B). Through this tube steam 

 from D, or carbonic acid from E, can be passed. 



Two other tubes, F and G, pass through the same cork — one for blowing steam 

 through the product, the other for carrying volatilised substances into the condenser H. 



The apparatus was employed as follows: — After opening the tubes containing the 

 product of the reaction, their tops were cut off with a file, and they were then placed in 

 front of a strong fire to liquefy their contents and to drive off as much hydrochloric and 

 hydriodic acids as possible. They were then allowed to cool in a nearly horizontal 

 position, so that their contents solidified on one side of the tube, leaving a clear passage 

 along their whole length. Next a stream of carbonic anhydride was passed through F 

 into A until it was quite full of the gas. Steam was then passed through C, and one of 

 the tubes B inverted over its open end, and rapidly pushed into the cork. Its contents 

 almost immediately liquefied and dropped into A without coming in contact with the air. 

 When the tube was completely washed out, it was removed and another one substituted. 

 The contents of twelve tubes were usually worked up at one operation (each containing 

 4 grms. oxide of zinc, 16 grms. phosphonium iodide, and 12 grms. chloride of benzyl) — 

 the last tube being left in the position shown in the figure. The tubes F and C were 

 then interchanged, so that steam passed through F, while a gentle current of carbonic 

 anhydride was passed through C. 



By this means the product was submitted to the prolonged action of steam and water 

 in a current of carbonic anhydride. The primary phosphine thus set free passed over 

 along with the steam, and was condensed in H, and then flowed into the separating funnel 

 I, which contained common salt to give greater density to the water, and thus cause the 

 phosphine to rise to its surface, as its specific gravity is almost the same as that of water. 



Without the above apparatus, we found it is almost impossible to separate the 

 phosphine without considerable loss through oxidation. 



