484 Dr. Atkinson on Monoacetate of Glycol, 



intcrcstiug body was first obtained by Wurtz^ its discoverer — that 

 is, by the action of iodide of ethylene on acetate of silver ; but 

 an easier method is a desideratum^ for Wurtz's method is unfoi'- 

 tunately attended with many disadvantages. The preparation 

 of iodide of ethylene, especially in large quantities, is difficult 

 and tedious, the other substance concerned in the reaction is 

 expensive, — Mhile, from the high equivalents of iodine and of 

 silvei', the proportion of acetate of glycol obtained must in any 

 case be small, and this is materially lessened by the fact that 

 the acetate of glycol is not the only substance produced in the 

 reaction. 



The expectation that the above-mentioned reaction would fur- 

 nish a ready means of obtaining glycol, has not been disap- 

 pointed. The following method, which leads to the preparation 

 of glycol, is easy and expeditious of execution ; the bromide of 

 ethylene is readily obtained pure, and is comparatively inexpen- 

 sive ; and the reaction is remarkably precise and definite. 



Abo At 60 grammes of pure bromide of ethylene are placed in 

 a soda-water bottle, along with an equal weight (very nearly 

 two equivalents) of fused acetate of potash, and -l fluid ounces of 

 80 per cent, alcohol. The bottle, well corked and tied down, is 

 placed in a water-bath and heated to 100° C. for two days, and 

 from time to time is well shaken. The bottle now contains a 

 liquid and a large quantity of crystals of bromide of potassium, 

 which latter are filtered off and washed on the filter with alcohol. 

 The filtrate is then distilled in a water-bath until nothing more 

 passes over at 100° C. This distillate consists of alcohol con- 

 taining acetic ether, and a small quantity of free acetic acid. 

 The residue is then transferred to a smaller retort in which a 

 thermometer is inserted, and rectified, the portions passing over 

 below 180° C, and above that point, being collected separately. 

 Occasionally, owing to the presence of some bromide of potas- 

 sium, the ebullition becomes so violent that it is necessary to 

 stop the distillation*. In that ease the residue in the retort is 

 digested with its bulk of absolute ether, and filtered. From this 

 ctherial solution the ether is first distilled oif in the water-bath, 

 and then the residue rectified, the distillate at and above 180° 

 being collected separately. 



The distillate above 180°, on being again rectified, consists 

 almost entirely of a substance boiling at 181°-182° C. This 

 is the 



Monoacetate of Glycol. 



It is a colourless, limjiid, oily liquid, with a faint odour and 

 a peculiar taste. It is perfectly neutral to litmus and turmeric 



* When absolute alcohol is taken, this is much less likely to occur. 



