612 



may be regarded as tetrethyl-phosphonium-salts, in which an equiva- 

 lent of hydrogen in one of the ethyl-molecules is replaced by bromine 

 and by the molecular group HO respectively. 



Bromide of tetrethylphosphonium [(C a H 4 H ) (C a H 5 ) 3 P] Br, 



Bromide of bromethylated tri- 1 rfr TT -n \ /p -p- x p-i -n, 

 ethylphosphonium . ....... j (C 2 H 4 Br ) (C 2 H 6 ) 3 P Br, 



[(C 2 H 4 HO)(C 2 H 5 ) 3 P] Br; 



and the question arose, whether the bromethylated compound might 

 not be converted, simply by reduction, into a salt of tetrethyl- 

 phosphonium. This transformation may, indeed, be effected with- 

 out difficulty. On acidulating the solution of the bromethylated 

 bromide with sulphuric acid and digesting the mixture with granu- 

 lated zinc, the latent bromine is eliminated as hydrobromic acid, its 

 place being at the same time filled by 1 equiv. of hydrogen, 

 [(C 2 H 4 Br) (C 2 H 5 ) 3 P]Br+2H = HBr+ [(C 2 H 5 ) 4 P]Br. 



It was chiefly the facility with which a tetrethyl-phosphonium- 

 compound may be obtained from the brominated bromide, that in- 

 duced me to designate the hydrogen-replacing molecules C 2 H 4 Br, 

 and C 2 H 5 O, which we meet with in the compounds above described, 

 as bromethyl and oxethyl. It remained to be ascertained whether 

 these compounds might actually be formed by means of direct sub- 

 stitution-products of ethyl-compounds. It was with the view of 

 deciding this question that I have examined the deportment of tri- 

 ethylphosphine with the monochloriuated chloride and the mono* 

 brominated bromide of ethyl. 



The former of these substances has been long known, having been 

 investigated by Regnault many years ago ; the latter had not been 

 hitherto obtained. I have prepared it by submitting bromide of 

 ethyl to the action of dry bromine under pressure*. It is a heavy 

 aromatic liquid boiling at 110. 



The chlorinated chloride and the bromiuated bromide of ethyl, 

 although essentially different in their physical properties from 

 dichloride and dibromide of ethylene, with which they are isomeric, 

 nevertheless resemble the ethylene-compounds in their deportment 

 with triethylphosphine. 



In both cases the final product of the reaction is a salt of hexethyl- 



* In addition to the monobrominated bromide of ethyl, (C 4 H t Br) Br, there is 

 also formed in this reaction the dibrominated bromide, (C 4 H 3 Br 2 ) Br. 



