424 
CHEMISTRY: M. GOMBERG 
ETHYLENE CHLORHYDRIN 
By M. Gomberg^ 
Chemical Laboratory, University of Michigan 
Communicated, July 30, 1919 
Within a few days after the so-called ''Mustard Gas'' was introduced 
(July 12-13, 1917) as a means of offence, it was definitely identified as 
/3-/3-dichlorethylsulphide. There was good reason to believe that it had 
been manufactured from ethylene chlorhydrin, according to the method 
described some thirty years previously by V. Meyer. ^ The reactions 
involved in that method are these: (1) Ethylene chlorhydrin in solution 
reacts with sodium sulphide and gives, in good yield, dihydroxyethylsul- 
phide, which is non-poisonous; (2) this product gives on treatment with 
concentrated hydrochloric acid the highly toxic /5-i3-dichlorethylsulphide : 
2 HOCH2CH2CI + NasS = (HOCH2CH2)2S + 2 NaCl 
(HOCH2CH2)2S + 2 HCl = (C1CH2CH2)2S + 2 H2O 
The problem however was, — how to get the chlorhydrin itself? From 
the practical standpoint, a process based upon the additive reaction be- 
tween ethylene and hypochlorous acid seemed most promising, notwith- 
standing the facts that this acid could only resist in concentrations of 
1 to 3%, and that the best yield of chlorhydrin by this method was 
known to be not more than 30% of the theory. 
The reaction between chlorine and water was employed as the source 
of hypochlorous acid. As is well known, this reaction yields extremely 
little hypochlorous acid, the equilibrium favoring largely the left-hand 
side of the equation. Nonetheless, it was found that if ethylene and 
chlorine in equimolecular amounts are passed into cold water and the 
mixture is well stirred, chlorhydrin, and not ethylene chloride, is the 
principal product. This is explained on the assumption that reaction II 
proceeds with considerably greater velocity than reaction I. 
I HOH + Cl — HOCH-HCl II 
C2H4 i- J' C2H4 
C2H4CI2 CIC2H4OH 
While a concentration up to 15% of chlorhydrin can be attained in 
this way, in practice it has been found advisable to stop with a concen- 
tration of 7 to 8%. The progress of the reaction is ascertained by dis- 
tilling a small sample of the product and determining its refractive index, 
that of water being 1.333 while that of chlorhydrin was found to be 1.442. 
