156 OXALIC ACID. 



long entangled needles ; inodorous and tasteless ; insol- 

 uble in cold water, slightly in hot water; partially 

 sublimable without decomposition. Heated in closed 

 vessels up to 200 with water, it is converted into 

 neutral ammonium oxalate. 



CO.NH.C 2 H 5 

 Dietnyloxamide, QQ j^jj Q 2 jj5 I s produced by 



bringing together oxalic ether and ethylamine. Color- 

 less crystals, difficultly soluble in cold water, easily 

 soluble in hot water. When distilled with caustic 

 potassa, it yields potassium oxalate and pure ethyl- 

 amine. "Well adapted for the preparation of ethylamine 

 in a pure condition and for separating it from di- and 

 triethylamine.* 



Oxamic acid, C^NO 3 = is produced by 



heating acid ammonium oxalate ; and by continued boil- 

 ing of oxamide with strong aqueous ammonia. It is 

 separated from the ammonium salt, obtained in this 

 way, by means of hydrochloric acid. White, crystal- 

 line powder, difficultly soluble in cold water; is rapidly 

 transformed into acid ammonium oxalate by boiling 

 with water. Monobasic acid, gives crystallizing salts. 

 Its ethers result from the action of dry or alcoholic 

 ammonia on the ethers of oxalic acid. The ethyl ether 



CO.NH 2 

 (oxamethari) AQ Q Q 2 TT 5 forms large, colorless, laminous 



crystals. 



OHO 

 Glyoxal (Oxalic aldehyde), C 2 H 2 2 = Is 



produced as a secondary product in the preparation of 

 glycolic acid from alcohol (p. 145). Solid, amorphous 



* Diethylamine, when brought together with oxalic ether, yields 



CO.N(C2H5)2 

 ethyl diethyloxamate Q Q C2 jjs a li( l uid boiling at 250-254. When 



this is distilled with caustic potassa, it yields pure diethylamine. Oxalic 

 ether does not act upon triethylamine. 



