464; Royal Society ; — 



from glycol, an aldehyde of the composition of acetic acid or of the 

 formula C^ H., 0^ may be produced. Glyoxal, obtained by the oxida- 

 tion of ethylie alcohol, has indeed the composition corresponding to 

 the above formula and the characteristic properties of an aldehyde. 

 Nitric acid converts it mpidlj' into oxalic acid. Consequently glycol, 

 glyoxal, and oxalic acid bear a similar relation to each other as ethylie 

 alcohol, aldehyde, and acetic do. 



' aH„o ari.o aii.o.. 



Alcohol. Aldehyde. Acetic acid. 



C,H,0, C,H,0,, C,H,0, 



Glycol. Glyoxal. Oxalic acid. 



Another connexion between glycol and glj'^oxal is that they both pro- 

 duce glycolic acid, the former by oxidation, and the latter by combi- 

 nation with one atom of water. I treated glycol, which was diluted 

 with water, with fuming nitric acid at about 30° C, and evaporated 

 the acid liquid, as soon as the action was completed, on the water- 

 bath until it assumed the consistency of syrup*. This residue was 

 found to contain, as previously shown by Wurtz, oxalic and glycolic 

 acids ; but I also found therein glyoxylic acid and a body which com- 

 ported itself with some reagents like glyoxal. Want of material, 

 however, prevented its being identified with the latter. 



Before I proceed to make some observations on these facts, I shall 

 first mention a few salts of glyoxylic acid not yet described. 



Glyoxylate of silver, C^HAgO^ + H^O, 



is obtained as a white crystalline powder when nitrate of silver is 

 precipitated with glyoxylate of ammonia. This salt is but slightly 

 soluble in cold water, and is decomposed by light with great rapidity. 



Glyoxylate of baryta, C,HBa03-l-2H2 0. 

 Diluted glyoxylic acid is digested at common temperatures with car- 

 bonate of baryta until the acid is completely neutralized, and the fil- 

 tered solution evaporated in vacuo. As soon as the liquid has arrived 

 at a certain degree of concentration, small white crystals of glyoxylate 

 of baryta begin to separate. This compound is partially decomposed 

 into oxalate of baryta and glycolic acid if it be heated to 120° C, or 

 if the temperature of its watery solution be raised to the boiling- 

 point. With nitrate of silver, acetate of lead, and lime-water, it com- 

 ports itself like glyoxylate of lime. 



Glyoxylate of zinc, Cj, Zn^ 0^-\-2')l^ O, 

 is produced as a white crystalline precipitate when a strong solution 

 of glyoxylate of lime is precipitated with acetate of zinc. This 

 compound is slightly soluble in water, but is easily dissolved by 

 acetic and hydrochloric acids and by caustic potash. The two atoms 

 of water cannot be removed without decomposing the salt. 



* " On the Action of Nitric Acid on Alcohol," Phil. Mag. Jan. 1857 ; Ann. der 

 Chem. uud Pharm. cii. 26. 



