410 
DE. A. AV. HOIAIAXX OX THE PHOSPHOEUS-BASES. 
Preparation of Triethylphosphine. 
The whole of the material used in my experiments was prepared by the process 
formerly described in detail by Cahoues and myself The only alteration, which has 
been found advisable, relates to the separation of the triethylphosphine from the chloride- 
of-zinc-compound, which is produced by the action of trichloride of phosphorus on zinc- 
ethyl. It was formerly our practice to throw solid hydrate of potassium into the viscid 
mass of this salt, and then to dissolve the potassa by gradually dropping water into the 
retort, the heat resulting from the reaction being sufficient to cany over the base nearlv 
anhydrous. It is better, however, to mix the double salt at once with water, and then 
decompose it in a retort filled with hydrogen, by allowing strong potassa-solution slowly 
to fiow into it. On subsequently distilling the mixture on a sand-bath in a continuous 
but very slow stream of hydrogen, the triethylphosphine passes over with the aqueous 
vapour and floats on the top of the condensed water in the receiver. By adopting this 
mode of proceeding, the reaction is more under the command of the operator, and as 
the phosphorus-base is not sensibly soluble in water, the quantity of the product is not 
thereby diminished. 
By exact adherence to the prescribed conditions, it is by no means difficult to prepare 
considerable quantities of pure triethylphosphine ; nevertheless the amount obtamed is 
always less than it should be in proportion to the weight of the materials used. This 
loss is mainly due to the formation of secondary products, which cannot be wholly 
avoided even when the zinc-ethyl is carefully prepared, and to partial decomposition 
of the latter substance during distillation: for it is scarcely possible to imagine a 
more elegant reaction than that which takes place between trichloride of phosphorus 
and ready-formed zinc-ethyl. Under these circumstances, many attempts were natuinlly 
made to obtain the phosphorus-base in other ways ; I have always, however, retui’ned to 
our original process. 
Totally unsuccessful was the attempt to obtain triethylphosphine, without prerious 
preparation of zinc-ethyl, by exposing a mixture of I equiv. of trichloride of phosphorus 
and 3 equivs. of iodide of ethyl with excess of zinc in sealed tubes to a temperature of 
150° C. The bodies react under these circumstances ; but as only traces of triethvlphos- 
phine are produced, I have not thought it worth while to piu-sue this reaction further. 
A more favourable result was obtained by heating a mixture of zinc and phosphorus 
with anhydrous iodide of ethyl to between 150° and 160°. After several hours’ digestion, 
the tubes were found to be coated with white crystals, and a considerable portion of the 
phosphorus had passed into the red modification. Powerful escape of gas always took 
place on opening the tubes, and in several instances they were shattered, even when their 
points were softened in the lamp-flame to diminish the violence of the concussion. 
Besides zinc-ethyl, the presence of which is indicated by the abundant evolution of 
hydride of ethyl which is observed on treating the contents of the tube with water, the 
chief products of this reaction are three phosphorus-compounds, which are formed in 
proportions varying according to the temperature and the duration of the action. 
