Ammonia upon Ethyl Oxalate. 481 



stricted in bore was used, since in the operation to follow 

 ammonia gas was led in through this tube. The weighed 

 ethyl oxalate was thoroughly chilled in a mixture of ice 

 and salt by immersion of the Claissen flask connected with 

 its receiver ready for the vacuum distillation to follow, and 

 was kept as cool as possible with this mixture during the 

 period of treatment with ammonia. The flask was shaken 

 violently at frequent intervals to facilitate the cooling of 

 the mixture, but more particularly to break up the solid mass 

 of precipitate and allow as complete contact as possible 

 between the ammonia gas and the liquid ethyl oxalate. After 

 the ammonia had been passed in for the time stated, the 

 flask was removed from the freezing mixture and the system 

 evacuated by the water pump. The receiver being kept 

 cool by a stream of cold water, the Claissen flask was heated 

 first with a water bath, brought slowly to the boiling point, 

 and finally at 115° with a bath of acid potassium sulphate to 

 drive off completely the ethyl oxalate, which was collected as 

 already described and weighed ; similarly the ethyl oxamate 

 was distilled and weighed. The weight of the residue left in 

 the Claissen flask was taken as the weight of the oxamide pro- 

 duced. The first period of heating at 115° to drive off the 

 ethyl oxalate was uniformly made of a half hour's duration. 

 It was presumed that during this heating all alcohol together 

 with any excess of ammonia would be driven out. Incidentally 

 there must have been a slight loss of ethyl oxalate carried off 

 in vapor form to the pump. In subsequent heatings to com- 

 plete the separation of ethyl oxalate, the loss in weight of the 

 Claissen flask was taken to represent the weight of ethyl 

 oxalate separated, rather than the weight of ethyl oxalate con- 

 densed in the receiver. The weight was, however, taken as a 

 check. The loss of ethyl oxalate in vapor form was naturally 

 largest when perceptible amounts of ethyl oxalate were distil- 

 ling during the longest periods of time. In the experiments 

 of Table I the largest amount of this loss observed was 0*043 

 grm. At the higher temperatures at which the oxamate 

 distilled the rubber stoppers lost somewhat in weight, but no 

 correction was made for the error thus introduced. 



In experiment (1) of Table I the ratio between the ethyl 

 oxamate and the oxamide formed is 3*09: 1; in (2), 3*67:1 

 although in (2) there is a much larger amount of unchanged 

 ethyl oxalate. We observed nothing which could be definitely 

 assigned as the cause of this fact. There was a falling off in 

 the amount of oxamate found in relation to the amount of 

 oxamide in experiments (3) and (4) when compared with that 

 in experiments (1) aud (2). The solid mass was better broken 

 up by shaking in the case of (3) and (4), thus indicating that 



