p-Nitroaniline

p-NITROANILINE, a crystalline yellow powder, difficult to dissolve in water, easier in alcohol and ether, melting point 147°. p-Nitroaniline finds application in the dyeing industry, where it is a component of diazo dyes. p-Nitroaniline is produced at aniline plants by means of the acetylation of aniline, the nitration of the resulting acetanilide, as a result of which nitroaniline is formed; this is followed by processes of separating the isomers of nitroaniline, drying, pouring, and grinding. The latter processes, as they are accompanied by the release of a large amount of dust (according to data from the Obukh Institute, from 13 to 67 mg of dust per 1 m³ of air was found in a number of places), are the most dangerous: of the 13 cases of acute poisoning by p-nitroaniline that passed through the clinic of the same institute (1928), in 11 cases the poisoned individuals were workers engaged in drying, pouring, and grinding. With a relatively small number of workers employed with it, p-nitroaniline causes a significant number of acute and chronic poisonings. In dyeing factories, poisonings also occur repeatedly; for example, in 1926 at the Yegoryevsk Dyeing Factory, 7 female workers engaged in washing dyed yarn were poisoned (Shustov), and in 1928 at the Sverdlov Factory (Moscow), 8 workers engaged in the diazotization of p-nitroaniline were poisoned. Observations by both foreign (Curschmann, Kunkel) and Russian authors (Yablokov-Sapozhnikov-Leytes, Genkin, Smirnova-Speransky) indicate that the phenomena of p-nitroaniline poisoning are very similar to the phenomena of aniline poisoning (see). As Genkin points out, it is not possible to identify any distinctive influence of p-nitroaniline on the morphology or the physical-chemical state of the blood; only a stronger effect of p-nitroaniline on the cardiovascular system is noted, which is also indicated by data from the Obukh Institute: in cases of aniline poisoning, toxic changes in the heart were found in 22 out of 36 cases, while in cases of p-nitroaniline poisoning, in 16 out of 19; in the latter, increased blood pressure and a slowing of the pulse were found much more often. Furthermore, a stronger influence of p-nitroaniline on the liver was established: jaundiced coloration of the sclera and bilirubin in the blood are found much more often (in 8 cases out of 15, a positive direct reaction for bilirubin according to Hijmans van den Bergh was obtained). Prevention. Since the most dangerous moments at aniline plants are the processes of converting p-nitroaniline into a powdery state, and at textile factories, on the contrary, the conversion into a wet state, in 1928 a proposal was put forward (Baskevich) to carry the process at aniline plants only to the stage of obtaining p-nitroaniline from the crystallizer and to use it at dyeing factories in the form of a paste; as experiments have shown, the technological effect is satisfactory. Therefore, a transition of all factories to this method of work is desirable. At aniline plants, all basic processes should be mechanized: the loading of acetic acid and aniline, the feeding of aniline into acetylators and the unloading of acetanilide, the feeding and loading of the nitrating mixture or acids, etc.; at all places where the release of vapors, gases, and dust is possible, local exhaust ventilation, etc., should be installed (decree of the People's Commissariat of Labor of the USSR of 29/VIII 1929). Furthermore, general measures for combating occupational poisonings are necessary (see Poisonings, occupational).