620 DR E. A. LETTS ON THE ACTION OF IODACETIC AND OF 
These numbers agree with the percentage of barium calculated for the anhy- — 
drous methyl-thioglycollate of barium— 
(CH,—S—CH,—CO,),Ba requires 39°48 per cent. barium. 
As no method of purifying this salt presented itself, it appeared desirable to 
saponify the ether with a base other than baryta, in order to obtain the corre-_ 
sponding salt for examination, and for that purpose caustic soda was employed, 
or rather a solution of sodium in alcohol. A quantity of the liquid product 
was boiled with this until the reaction ceased to be alkaline. The resulting 
solution contained a crystalline salt in suspension, which, no doubt, consisted 
of thiodiglycollate of sodium. It was filtered from this and evaporated to 
dryness on a water-bath, when it left a crystalline residue. This was treated 
with water and dissolved easily, leaving, however, a few oily drops, which pro- 
bably consisted of unsaponified ether. The solution filtered from these was 
evaporated on a water bath to dryness, redissolved in alcohol, again evaporated 
to dryness, and the remaining salt dried at 110° C. till it ceased to lose 
weight. 
The determination of sodium in the salt thus dried showed that it consisted 
of methyl-thioglycollate of sodium, CH;—S—CH,—CO,Na. 
‘2025 gave 1105 sulphate of sodium = ‘0358 sodium = 17°7 per cent. 
2 1o0) Loli) . hl Ge 0480S S17 ae 
CH,—S—CH,—CO,Na requires ; 3 : ; 178 
»? 
Further proof of the presence of methyl-thioglycollate of ethyl in the product 
was afforded by the production of a crystalline compound when it was mixed 
with alcoholic corrosive sublimate solution.* The resulting compound was not, 
however, submitted to analysis. . 
The above experiments show that the action of iodacetic ethyl ether on 
sulphide of methyl is similar to the action of bromacetic acid on many hydro- 
carbon sulphides, that is to say, that the halogen and sulphur change places. 
The production of methyl-thioglycollate of ethyl as a far more abundant 
product than thiodiglycollate of ethyl shows, however, that the reaction occurs 
in two distinct stages, in the first of which only one of the methyl groups of 
sulphide of methyl is replaced by the group CH,—CO,C,H;, whilst in the 
second the remaining methyl group is similarly replaced. The action may be 
compared with that of iodacetic or bromacetic acid on ammonia, by which 
* J. Wisticenus, “ Zeitsch. fiir Chem.” 1865, p. 625, mentions a compound of thioglycollic ethyl 
ether and corrosive sublimate, to which he assigns the formula C,H,SO,.HgCl. No doubt the com- 
pound obtained as above would have a similar composition. 

