480 Phelps, Weed, and Housum — Action of Dry 









Table I. 











Ethyl 

 oxalate 



Unchanged 



Ethyl Oxaniic 

 oxalate ester 



Oxamide 



Ethyl 



oxalate 



accounted 



for 



Reaction 

 time 



Loss of 

 Ethyl 

 oxalate 



No. 



grin. 



grm. grm. 



grm. 



grm. 



niin. 



grm. 



(1) 



22-319 



0-545 12-714 



3-461 



22-144 



20 



0-175 



(2) 



13-667 



3-243 5-798 



1-872 



13-580 



27 



0087 



(3) 



9-627 



0*240 4-375 



2-300 



9-510 



25 



0-117 



(4) 



10-944 



0-828 4-408 



2-713 



10-825 



23 



0-119 



After the flasks had been evacuated to a pressure of 15 mm , the 

 mass of the ester was distilled by plunging the flask into a bath 

 of acid potassium sulphate heated to 200°. By flaming the 

 Claissen flask and increasing slightly the current of air through 

 the flasks, the remaining traces of ester are driven either into 

 the flask used as a receiver or into the extension tube leading 

 into it. The increase in weight of this flask with its rubber 

 stopper and the extension tube was taken as the weight of the 

 ethvl oxamate distilled. This amounted to 7*6361 grm.' show- 

 ing a loss of 0-0135 grm. in distillation under these conditions. 

 It was found further that by the use of this apparatus a mix- 

 ture of ethyl oxalate and ethyl oxamate could be separated and 

 each determined. The ethyl oxalate was first distilled off by 

 heating the Claissen flask after evacuating the flasks to a 

 pressure of 15 mm in a deep bath of acid potassium sulphate, the 

 flask being plunged into the bath as deeply as possible and the 

 receiver being kept cool by a stream of cold water striking it 

 constantly during distillation. This operation was continued 

 until the Claissen flask when heated for half an hour under 

 these conditions showed a loss in weight as small as 0*010 grm. 

 between successive weighings. A mixture composed of 

 10-7749 grm. of ethyl oxalate and 3-3184 grm. of ethyl oxam- 

 ate gave by heating with the arrangement of apparatus as 

 described above, with the bath at 115°, a distillate of 10*7151 

 grm., showing a loss consequently of only 0*0598 grm., of ethyl 

 oxalate ; and by heating further with the bath at 200°, a distill- 

 ate of 3*3015 grm., showing here a loss of only 0*0169 grm. of 

 ethyl oxamate. Since oxamide undergoes no change when 

 heated to 200° under diminished pressure, it is possible to sepa- 

 rate and estimate mixtures of ethyl oxalate, ethyl oxamate, and 

 oxamide. Table I records the results of experiments obtained 

 by treating the recorded weights of the pure ethyl oxalate with 

 the dry ammonia gas prepared as already given. The ethyl 

 oxalate was weighed out in the Claissen flask of the apparatus 

 described above after the apparatus had been dried by leading 

 through it dry air for half an hour. In place of a capillary 

 tube usually used in a vacuum distillation, a tube not con- 



