Dr. Debus on the Action of Nitric Acid on Glycerine. 197 



glycerine. The propylic alcohol stands to glycerine most pro- 

 bably in the same relation as common alcohol stands to glycol, 

 Qi JJ6 Q2_ Many facts are in accordance with this view, viz. 

 the formation of propionic acid from glycerine during fermenta- 

 tion. The action of nitric acid on common alcohol produces a 

 substance for which I proposed the name of glyoxylic acid. It 

 appeared probable, according to the above theoretical considera- 

 tions, that, under similar conditions, an acid might be formed 

 from glycerine homologous with glyoxylic acid. The experi- 

 ments which I undertook have realized this expectation. 



One part of glycerine is mixed with a little more than its bulk 

 of water, and the mixture placed in a long and narrow bottle. 

 By means of a glass tube drawn out to a point at one end, one 

 part and a quarter of red fuming nitric acid is allowed to collect 

 under the mixture of glycerine and water in such a way that two 

 distinct layers, the one of acid and the other of diluted glycerine, 

 arc formed. The bottle thus charged is put into a place where 

 it can remain without being disturbed for six or eight days. The 

 temperature should be about 20° C. The nitric acid gradually 

 mixes with the glycerine, the liquid assumes a blue colour, and a 

 brisk evolution of gas takes place which lasts for several days. 

 As soon as the generation of gas ceases and the liquid has be- 

 come colourless, the reaction may be considered to be at an end ; 

 but generally I allowed a few days more before 1 proceeded with 

 the following operations. 



In order to get rid of the excess of nitric acid and other vola- 

 tile compounds, the contents of the bottle were evaporated in 

 small portions on the water-bath till the liquid assumed the 

 consistency of a strong syrup. The latter was dissolved in water, 

 neutralized with chalk, and the lime-salts produced were precipi- 

 tated with strong alcohol. A pasty precipitate was obtained. The 

 liquid, which still contained one or two substances which do not 

 crystallize, was carefully poured oflf and placed aside. The precipi- 

 tate was treated with boiling water, and the solution filtered off 

 from the undissolved carbonate and oxalate of lime. To the clear 

 filtrate was added slaked lime till it became distinctly alkaline. 

 The slaked lime removes a syrupy substance which interferes 

 with the crystallization of the body desired. The precipitate was 

 filtered off, the excess of lime thrown down from the solution by 

 carbonic acid, and the filtrate from the carbonate of lime con- 

 centrated by evaporation. On allowing it to stand, a large 

 quantity of beautiful crystals was obtained. These crystals are 

 the lime-salt of a substance for which I propose the name of 

 glyceric acid. They may be easily purified by rccrystallization. 

 Of the other bodies produced by the action of nitric acid ou gly- 

 cerine, I shall treat on another occasion. 



