IN a 2-l. round-bottom flask, fitted with a stopper holding a dropping funnel and a mechanical stirrer, is placed a mixture of 275 cc. of concentrated nitric acid (sp. gr. 1.42) and 275 cc. of concentrated sulfuric acid (sp. gr. 1.84). This is cooled to 10'0 in a freezing mixture, and 100 g. of benzyl cyanide (free from alcohol and water) are run in slowly, at such a rate that the temperature remains at about 10'0 and does not exceed 20'0. After all the benzyl cyanide has been added (about one hour), the ice bath is removed, the mixture is stirred for an hour and then poured on to 1200 g. of crushed ice. A pasty mass slowly separates; more than half of this mass is _p_-nitrobenzyl cyanide, the other constituents being _o_-nitrobenzyl cyanide, and a variable amount of an oil which resists hydrolysis; apparently no dinitro compounds are formed. The mass is filtered on a porcelain funnel with suction, pressed well to remove as much oil as possible, and dissolved in 500 cc. of boiling alcohol (95 per cent). On cooling, _p_-nitrobenzyl cyanide crystallizes; the mother liquor, on distillation, gives an impure alcohol which can be used for the next run. Recrystallization from 550 cc. of 80 per cent alcohol (sp. gr. 0.86 to 0.87) yields 70 to 75 g. (50-54 per cent) of a product which melts at 115-116'0. This product is satisfactory for most purposes, and incidentally for the preparation of _p_-nitrophenylacetic acid. Occasionally it must be free even from traces of the ortho compound, and in this case should be crystallized again from 80 per cent alcohol; it then melts at 116-117'0. 2. Notes Fuming nitric acid may be used in nitrating benzyl cyanide, but the method here described is cheaper. The yield of 70 g. is obtained from benzyl cyanide, which boils over a 5'0 range prepared as described in preparation III (p. 9). Very pure benzyl cyanide will give a slightly higher yield, while commercial grades may give only 50 g. of _p_-nitrobenzyl cyanide and much oil. The reaction has been also carried out with 500 g. of benzyl cyanide. Under these conditions a 5-l. flask was used, and it required two and a half hours to add the benzyl cyanide. The yield of product was 325 to 370 g. 3. Other Methods of Preparation Nitrobenzyl cyanide has hitherto been prepared by the action of fuming nitric acid[1] on benzyl cyanide. [1] Ber. 17, 505 (1884); 33, 170 (1900); J. Biol. Chem. 39, 585 (1919); J. Am. Chem. Soc. 43, 180 (1921). XV _p_-NITROPHENYLACETIC ACID (_p_)NO2C6H4CN + H2SO4 + 2H2O--> (_p_)NO2C6H4CH2CO2H + NH4HSO4 Prepared by G. R. ROBERTSON. Checked by ROGER ADAMS and H. O. CALVERY. 1. Procedure