[ 367 ] 



LX. Notices of the Results of the Labours of Contine7ital 



Chemists. By Messrs. W. Francis and H. Croft. 



[Continued from p. 293.] 



Betizoenitric and Cinnamonitric Acids. 



TN the Annalen der Pharmacie, vol. xxx. p. 341, is a paper 



-*■ on Balsam of Peru, by Plantamour, in which a peculiar acid 



is mentioned, viz. the carbobenzoic; in vol. xxxiv. p. 297, is 



a treatise by Mulder on the benzoenitric acid; and in the 



Journal fur Praktischen Chemie, vol. xxii. p. 193, one by Mit- 



scherlich on cinnamonitric acid. These three papers are so 



intimately related that it is better not to separate them at all, 



but to consider them in one report. 



When benzoic acid is boiled with excess of nitric acid, it dis- 

 solves and colours the fluid red; binoxide of nitrogen is given 

 off. The development of gas ceases after boiling for several 

 hours, and the solution becomes colourless. From the cold 

 solution crystals similar to benzoic acid are deposited, the 

 fluid eventually becomes one solid crystalline mass, from which 

 the benzoenitric acid may be extracted by boiling water 

 (Mulder). According to Mitscherlicli, the evolution of bin- 

 oxide of nitrogen is accidental ; it arises from the action of 

 nitric acid on the already formed benzoenitric acid ; it is 

 therefore not necessary to boil the fluid for any length of 

 time. 



The same acid is produced by the action of nitric acid 

 on several substances which have been said to be converted 

 into benzoic acid by nitric acid. Some substances first form 

 benzoic acid, as is the case with cinnamic acid and oil of 

 cinnamon when treated with dilute acid. Plantamour did 

 not discover the nitrogen in this acid : he gave the formula 

 C'^ H'"03; Mulder and Mitscherlich's formula is C'< H« O* 

 + N^O, or C'^H'oO N -H^O. 



This acid separates from water as a crystalline mass, it is 

 easily soluble in boiling water, and if there is not sufficient todis- 

 solveitall, an oleaginous substance is formed which is heavier 

 than water ; benzoic acid has the same property. At 10° C. 4C0 

 parts of water dissolve one part of the acid, at 100° ten parts. 

 It is easily soluble in alcohol and aether; melts at 127°, and 

 begins to sublime at 1 10"; the pure acid sublimes unchanged ; 

 chlorine has no action on it. Benzoenitric acid is not easily 

 decomposed by heated sulphuric acid; it becomes red, and 

 then contains an acid which gives a soluble salt with baryta. 

 Thebcnzocnitrates are for the most part soluble in water and 

 alcohol, crystallizable, explode by heating, and when gently 



