ACTION OF HYDROCARBON SULPHIDES ON BROMACETIC ACID. 615 
phide of allyl is lighter than water). These two were boiled for some time 
with solution of caustic baryta; excess of nitric acid was then added, and 
nitrate of silver solution, when an abundant yellow precipitate of bromide of 
silver was produced. 
The reaction which occurs between sulphide of allyl and bromacetic acid 
is then of the same nature as that between sulphide of benzyl and bromacetic 
acid—viz., production of thiodiglycollic acid and bromide of the hydrocarbon 
radical— 
(C3H;),8 + 2(CH,CO,H)Br = 2C,H,Br + S(CHCO,H),. 
Whether this reaction is preceded by the formation of a thetine compound 
has not as yet been ascertained. It might have been thought probable, con- 
sidering the ease with which bromine quits bromacetic acid, that an addition 
product containing the triad radical glyceryl might be formed, namely— 
CH CH,COOH 
CHCH,GOOH 
CH Br , 
but the experiments just described show that such a substance is not produced. 
Action of Bromacetic Acid on Sulphide of Ethylene.—It occurred to me that 
it would be of interest to study the action of these two substances on each 
other, to ascertain whether a thetine compound, containing a diatomic hydro- 
carbon radical, was capable of existence, or at least of ready formation, and if 
not, to see what course the reaction would take. 
Preliminary experiments showed that when the amorphous sulphide of 
ethylene is warmed with bromacetic acid, a brownish liquid results, which shows 
no tendency to crystallise on cooling, even though left to itself for some days. 
On heating the mixture, a volatile liquid passes off, which is accompanied 
later by hydrobromic acid, and when the reaction appears to have terminated 
a brown syrupy residue remains. 
These results induced me to study the action more carefully. 
45 orms. of carefully washed and purified sulphide of ethylene, and 15 
grms. of bromacetic acid carefully dried on blotting paper, were placed in a 
VOL. XXVIII. PART II. fw 
