292 M. Wiirtz on the Synthetical Formation of some New Acids, 



In continuing his researches*, Wurtz has examined the action 

 of oxidizing agents on these polyethylcnic alcohols, and has ob- 

 tained results of great interest, wnich will throw considerable light 

 on the constitution of the complicated vegetable acids. 



By oxidizing glycol, Wurtz obtained glycolic, lactic, and oxalic 

 acids by reactions quite analogous to those by which alcohol is 

 transformed into acetic acid. By oxidizing diethylenic alcohol, 

 an acid isomeric with malic acid is obtained ; and by oxidizing 

 triethylenic alcohol, a still more complicated acid is produced. 



The oxidation of diethylenic alcohol was effected either by 

 means of platinum-black, or by the action of nitric acid. In the 

 latter case the reaction was very violent, and a tumultuous dis- 

 engagement of nitrous fumes was observed. The acid liquid, 

 evaporated to dryness, formed a mass of crystals. These crystals 

 were dissolved in water, saturated with milk of lime, boiled, and 

 separated by filtration from a deposit of oxalate of lime which 

 had been formed. The liquor deposited, on cooling, a lime-salt, 

 which crystallized in long brilliant needles. Dried at 170°, these 

 crystals had the composition of a neutral and dry malate of lime. 

 The formula of the crystals is G 4 H 4 Ca 2 O 5 + 6 Aq j and they do 

 not completely lose this water below 160°. They are almost 

 insoluble in cold, and are difficultly soluble in boiling water. 

 The boiling saturated solution gives with nitrate of silver a gra- 

 nular precipitate, whose composition is € 4 H 4 Ag 2 O 5 , which is 

 the formula of malate of silver. 



AVhen this silver salt is diffused in water and decomposed by 

 sulphuretted hydrogen, an acid liquor is obtained, which, when 

 concentrated, deposits large rhomboidal prisms, very soluble 

 in water and in alcohol. Its composition is expressed by the 

 formula €* H 6 O 5 + H 2 0. The new acid effloresces slowly in the 

 air, and loses an atom of water of crystallization, which it parts 

 with much more rapidly in vacuo, or at 100°. The dry acid 

 melts at 148°, and solidifies to a crystalline mass. At about 250° 

 to 270° it decomposes, with disengagement of a combustible gas ; 

 the residue is a strongly acid liquor, which after some time soli- 

 difies to a crystalline mass, and which is a true pyrogenic acid. 



The new acid has the composition of malic acid, but differs 

 from it in form, in the amount of its water of crystallization, in 

 its efflorescing, and in comportment when heated. In one 

 respect it strongly resembles malic acid; fused with hydrate of 

 potash it gives off hydrogen, and forms acetic and oxalic acids : — 

 G 4 H 4 K 2 O 6 + KHO = € 2 K 2 O 4 + € 2 H 3 KG 2 + H 2 . 



Potash salt. Oxalate of Acetate of 



potash. potash. 



When a solution of the acid is half-neutralized with potash, 

 * Comptts Rendus, July 30, 1860. 



