8J8 GLYCERYL. 



Glycerin is thus obtained as a syrup, colourless or slightly 

 yellow and uncrystallizable, inodorous, very distinctly sweet, 

 of density 1.252 to 1.27, attracting moisture from the air, and 

 miscible in all proportions with water and alcohol, but insoluble 

 in ether. It rises in small quantity with the vapour of water, 

 but cannot be distilled without partial decomposition. When 

 heated in air glycerin burns with a luminous flame. It pos- 

 sesses an extraordinary solvent power, scarcely inferior to that 

 of water itself. It dissolves the deliquescent salts, and many other 

 salts which are not deliquescent, as sulphates of potash, soda 

 and copper, nitrates of silver and potash, the alkaline chlorides, 

 hydrates of potash and soda, and the vegetable acids. Nitric 

 acid converts it slowly into oxalic acid ; peroxide of manganese 

 with sulphuric acid into formic and carbonic acids. Its so- 

 lution in water does not undergo any change by keeping, and 

 is not fermentable by yeast. Glycerin is decomposed when 

 boiled with a solution of sulphate of copper, and metallic copper 

 precipitated. It is not precipitated by subacetate of lead, but 

 is itself when hot capable of dissolving oxide of lead. With 

 potash it forms a compound soluble in alcohol ; it combines also 

 with barytes. 



It is acted upon by chlorine and bromine ; the latter forms, 

 with hydrobromic acid, a heavy oily ethereal liquid, C 12 H H Br 3 

 O 10 , soluble in alcohol and ether. With chlorine, the product is 

 a white solid flocculent substance, C lt2 H. ll d 3 O lo . 



Acid sulphate of oxide of glyceryl, suiphoglyceric acid; 

 HO. C 6 H 7 O 5 + S 2 O 6 . When glycerin is mixed with twice its 

 weight of concentrated sulphuric acid, combination takes place 

 with the evolution of much heat, but without charring. The 

 liquid when diluted and neutralised with carbonate of lime gives 

 a precipitate of sulphate of lime, which is separated by nitration, 

 while sulphoglycerate of lime remains in solution. The acid 

 may be isolated by cautiously precipitating the lime by means of 

 oxalic acid. But it cannot be preserved, for it is gradually 

 decomposed and converted into hydrate of oxide of glyceryl and 

 sulphuric acid ; the change takes place still more rapidly when 

 the liquor is slightly heated. Even when newly prepared, this 

 acid liquid precipitates lime and barytes from their salts. 



Sulphate of oxide of glyceryl and lime, CaO.C 6 H 7 O 5 + S 2 O 6 , 

 (Pelouze.) It is deposited from its solution evaporated to the 



