BENZYL PHOSPHINES AND THEIR DERIVATIVES. 543 



almost solid, from the separated hydriodate. The mass was thrown on to a linen filter and 

 thoroughly squeezed, then pressed between filter paper, broken up, and washed with 

 benzol, so long as the latter dissolved anything. The benzol was then removed as 

 far as possible by pressure between filter paper, and the purified hydriodate dried in 

 vacuo. 



The hydriodate prepared by both these methods was snow white, and tolerably per- 

 manent in the air ; but if not carefully prepared and thoroughly washed, it rapidly 

 became brown. About 60 grms. of the hydriodate thus prepared were placed in a sepa- 

 rate funnel, and caustic potash solution added until the funnel was nearly full ; the 

 mixture was then well shaken, when the hydriodate rapidly decomposed, and the 

 phosphine separated as an oily layer, which floated on the watery liquid containing 

 potash and potassium iodide. It was decanted, and submitted to fractional distillation in 

 a stream of hydrogen. The thermometer rose rapidly to 178°, then slowly to 190°. It was 

 fairly constant from 180°-182° when most distilled; only a little passed from 182°-190°. 

 Fraction 178°-190° was redistilled. The thermometer rose at once to 177°, and from that 

 temperature to 185° most distilled. The exact boiling point could not be fixed, but it is 

 somewhere about 180°-183°. These experiments, conducted with the greatest possible care, 

 and repeated two or three times, appear to indicate that the primary phosphine suffers a 

 slight decomposition during distillation, but it is also possible that, in spite of the precau- 

 tions adopted, the phosphine after all was not absolutely pure. 



Properties. — Monobenzyl phosphine is a colourless, highly refractive liquid, possessing 

 a very characteristic and penetrating odour. Its smell remains for days on the hands, 

 and in one case it was observed on an instrument months after the latter had 

 been handled by one of us, our fingers having been previously in contact with some 

 of it. 



Exposed to the air, it at once fumes very powerfully and grows hot. Its vapour indeed 

 often inflames spontaneously on leaving a bottle containing it open for some time. The 

 product of its oxidation is not a single substance, but contains no less than three different 

 bodies. 



Sulphur only acts upon it when the mixture is warmed. Torrents of sulphuretted 

 hydrogen are then evolved, and a liquid product is formed. 



It combines readily with hydriodic and hydrobromic acids, and also, though not so 

 energetically, with hydrochloric acid. The resulting compounds are crystalline, and are 

 very sparingly soluble in a saturated solution of the hydracid. They are volatile, with 

 decomposition more or less complete — unless in a stream of gaseous hydracid, when the 

 hydriodate and hydrobromate at all events sublime unchanged. They are immediately 

 decomposed by water and alkalies. Halogens act violently upon the phosphine, and 

 seize upon part (or all) of its hydrogen, the hydracid which is formed then combining with 

 the rest of the phosphine to produce its haloid salt. 



Bisulphide of carbon attacks it when the two are heated under pressure, sulphuretted 

 hydrogen escapes, and two sulphurised products result. 



VOL. XXXV. PART II. (NO. 15). 4 U 



