1872.] 



Dr. A. W. Hofmann on the Phosphorus Bases. 



223 



tertiary phospliines and the quartary phosphonium compounds previously 

 known, but which may be much more easily and plentifully obtained by 

 the new method. Phosphonium iodide has thus become a general agent for 

 the production of the alcohol derivatives of phosphoretted hydrogen. 



The formation of the several groups of phosphines by means of phos- 

 phonium iodide is represented by the following equations, in which the 

 reaction is assumed to be accomplished in the methyl series : — 

 Primary Phosphines. 

 2CH 3 1 + 2(H 3 P. Ill) + ZnO = 2[(CH 3 ) H 2 P . HI] + Znl 2 + H 2 0. 

 Secondary Phosphines. 

 2CH 3 1 + H 3 P.HI + ZnO = (CH 3 ) a H P . Ill + Zn I 2 + H 2 0. 

 Tertiary Phosphines. 

 3(CH 3 . HO) + H 3 P . HI = (CH 3 ) 3 P. HI + 3 H 2 0. 

 Quartary Phosphonium Compounds. 

 4 (CH 3 . HO) + Ii 3 P . HI = (CH 3 ) 4 PI + 4H 2 0. 



II. Primary and Secondary Methylic Derivatives of Phosphoretted 



Hydrogen. 



Owing to the superior interest attached to the monocarbon compounds, 

 I was induced, in the first place, to test the new reactions in the methyl 

 series. 



Phosphonium iodide, methylic iodide, and zinc oxide act upon one an- 

 other with remarkable facility. Two molecules of each of the iodides and 

 one molecule of zinc oxide were found to be appropriate proportions ; the 

 ordinary zinc-white of commerce may be employed. 



Since it was desirable to procure at once the new compounds in sufficient 

 quantity for a thorough examination, the digestion-tubes received consider- 

 able charges. If these tubes have a capacity of from 120 to 150 cubic 

 centims., 70 or 80 grms. of the agents involved in the process may be di- 

 gested without danger. It is not, however, desirable to pass these limits. 

 The compound first introduced is the phosphonium iodide, then follows 

 the zinc oxide, which is compressed into a solid layer in order to prevent 

 the methyl iodide, lastly poured in, rapidly to come in contact with the 

 phosphonium compound. In the presence of zinc oxide the two iodides 

 act upon each other even at the common temperature ; and without the 

 precaution just indicated, it would be difficult to draw out and seal the tubes. 

 Before being heated, the tubes must be strongly agitated in order to produce 

 a thorough mixture of the three substances. As regards the digestion, I 

 have been often satisfied to work at the temperature of boiling water; after 

 six or eight hours' exposure in a water- bath, the transformation is gene- 

 rally complete. If the tubes be heated to 150° in an air-bath, not more 

 than four hours are required. On cooling, the digestion-tubes are found to 

 contain a white crystalline solid ; they invariably hold a good deal of com- 

 pressed gas, so that some precaution is necessary in opening them before 

 the blowpipe. The gases generally issue with a loud report and a long 



