76 



PROPERTIES OF CERTAIN AMINO-ACIDS. [CH. IV. 



(xi.) Filter on a small Buchner funnel (fig. n), wash with a little 

 ice cold absolute alcohol, and dry in a desiccator. 



C 2 H 5 .OH+HOOC.CH 2 .NH 2 .HC1 = C 2 H 5 OOC.CH 2 .NH 2 .HC1.+H 2 O 



Glycine hydrochloride. Glycine ester hydrochloride. 

 Yield: 10 to 15 grams. 



B. The conversion of glycine ester hydrochloride 

 into glycine. 



(i.) Weigh the glycine ester hydrochloride, 

 place it in a 250 cc. round-bottomed 

 flask and add 10 cc. of water. 



(ii.) Add 100 cc. of ether and cool in a 

 freezing mixture. 



(iii.) Gradually add 33 per cent, caustic 

 soda, shaking well during the addi- 

 tion, until the aqueous layer is 

 neutral to litmus. About 0-8 cc. 

 are required for every gram of the 

 hydrochloride. 



(iv.) Add powdered potassium carbonate, 

 shaking vigorously between whiles, 

 until the watery layer is a paste. 

 By treatment with alkali the glycine ester hydrochloride 

 is converted into glycine ester, which is soluble in ether. 



(v.) Pour off the ether, filter it, and place it in a stoppered flask. 



(vi.) Add another 50 cc. of ether to the residue, shake well, 

 remove and filter the ether, adding it to that in the 

 stoppered flask. Repeat this once more. 



(vii.) Dry the ether by shaking for 5 to 10 minutes with about 

 20 grams of anhydrous potassium carbonate. Decant 

 the ethereal solution and remove the last traces of 

 water by means of anhydrous sodium sulphate. This 

 is prepared by strongly heating 25 grams, of sodium 

 sulphate in a porcelain dish and cooling the warm melt 

 in a desiccator. Allow the cool, finely powdered, sul- 

 phate to stand with the ether for at least six hours. 



Fig. ii. Buchner 

 funnel and filter- 

 ing flask. 



