1894-95.] Sodium Mercaptide on Dibromo-Malonic Ether, 383 
Note on the Action of Sodium Mercaptide on Dibromo- 
Malonic Ether. By Prof. Crum Brown and Robert 
Pairbairn, B.Sc. 
(Read March 18, 1895.) 
We examined the action of sodium mercaptide on dihromo- 
malonic ether in the hope that in this way we might obtain the 
substance C(S — 02115)2(00002115)2. We found, however, that 
the reaction takes a different direction, and that what happens is 
represented by the equation 
2CBr2(COOC2H,)„ + 4NaSC2H5 = ^coO^h')^ + 2(C2H5)2S2 + 4NaBr . 
The same action took place whether the dihromo-malonic ether 
was dissolved in ether and gradually added to the sodium mercap- 
tide suspended in ether, or the dihromo-malonic ether and the 
mercaptide were each dissolved in alcohol and mixed. The product, 
after the ether or alcohol was distilled off, was distilled in vacuo. 
The fraction passing over between 200° and 250° soon solidified as 
a yellow crystalline mass. This was very soluble in benzene, and 
very sparingly so in ligroin ; slightly soluble in alcohol, in ether, and 
in hot water; practically insoluble in cold water. It was easily 
purified by dissolving it in the smallest possible quantity of benzene, 
and then adding ligroin. From the mixture the substance sepa- 
rated in large transparent monoclinic crystals. Analysis gave the 
following results : — 
I. 0T914 grm. substance gave 0*3684 CO2 and 0*1173 H2O 
II. 0*1878 „ „ 0*3595 „ „ 0*1071 „ 
■r TT Calculated for 
CiAoOs. 
C, . . . 52*48 52*22 53*17 
H, . . . 6*81 6*33 6*33 
The crystals fused at 57°. There could he no doubt that the 
substance was the “ dicarhintetracarhonsaure athylester” of Conrad 
