112 M. Fischer on some New Acids. 



soluble in hot water, alcohol, and ether, at 100° lose water of 

 crystallization, and at 210° melt with partial decomposition. 

 The formula of the dehydrated acid is C 14 H 8 6 , which is the 

 same as that of oxybenzoic and salicylic acids. Its formation 

 may be thus expressed : — 



HO, C 16 IF O 5 + HI = C 2 H 3 1 + HO, C 14 H 6 O 5 . 



Anisic acid. Iodide of New acid, 



methyle. 



The new acid differs essentially from salicylic acid, more espe- 

 cially in that it does not give with perchloride of iron the violet 

 colour characteristic of the latter acid. It also differs from oxy- 

 benzoic acid, although it stands nearer to it in many respects 

 than to salicylic acid. Saytzeff names it Pwaoxybenzoic acid. 

 It is a strong acid, and forms with the oxides of zinc and cad- 

 mium and with the alkaline earths well-defined salts. 



When crude nitrobenzole, prepared from benzole containing 

 toluole, is treated with dilute soda lye, and the alkaline liquid 

 supersaturated with hydrochloric acid, an acid precipitate is 

 obtained, which, after being purified by recrystallization, has 

 much similarity with benzoic acid. Fischer, who made this 

 observation*, had the opportunity of examining a specimen of 

 this substance which had been obtained as a by-product in a 

 manufactory. It was found on analysis to have the composition 

 of nitrobenzoic acid, C 14 H 5 NO 8 , and is obviously a product of 

 oxidation of toluole ; its formation may be thus expressed : — 



C 14 H 6 + 3HO N0 5 =HO C 14 H 4 (N0 4 )0 3 + 4HO +2N0 3 . 



Toluole. Nitro-acid. 



This new acid, although identical in composition with nitro- 

 benzoic acid, differs materially in a great many points, most 

 remarkably in the melting-point, which in the case of nitroben- 

 zoic acid is 227° C, and in the new acid (which he names 

 paranitrobenzoic acid) is 240° C. The salts of the two acids 

 differ also. 



From their isomerism, it might be supposed that nitroben- 

 zoic and paranitrobenzoic acids stood to each other in the same 

 relations as benzoic and salylic acidsf. To decide this point, the 

 simplest plan was to convert the paranitrobenzoic acid into the 

 amido-acid, and this by treatment with nitrous acid into the cor- 

 responding oxyacid, which ought then to be identical with sali- 

 cylic acid. Experiments have not confirmed this supposition, but 

 they have led to the discovery of a new acid isomeric with amido- 

 benzoic acid, and of an acid isomeric with oxybenzoic and sali- 



* Liebig's Annalen, August 1863. 

 t Phil. Mag. vol. xx. p. 383. 



