from first principles PP-I-1

PP-III-58Kinetic Features of the Hydrogenation of 4-Nitroanilinein Aqueous 2-Propanol Solutions on Skeletal NickelLefedova O.V., Nguyen T.T.H.Ivanovo State University of Chemistry and Technology, Ivanovo, Russianguyenha_isuct@ymail.comThe processes of liquid-phase catalytic hydrogenation of unsaturated organic compounds arewidely used in various fields of chemistry and chemical technology. One of the mainproblems of fine organic synthesis is the development of methods for selecting the optimalconditions for reactions involving substituted nitrobenzene.The kinetics of the hydrogenation of 4-nitroaniline on skeletal nickel catalyst in aqueous2-propanol solutions of azeotropic composition was studied. This system was also studiedwith the addition of acetic acid and sodium hydroxide.We used a comprehensive approach that includes the study of liquid-phase hydrogenationreactions that is kinetic method and the analytical monitoring of the process by gas-liquidchromatography.It was experimentally shown that in aqueous 2-propanol solutions of azeotropic composition,the hydrogenation reaction of 4-nitroaniline on skeletal nickel catalyst proceeds selectively toamine, without accumulation of intermediate products in the liquid phase. It was observedthat the hydrogen that is related to the active centers of the catalyst surface takes part in thereduction of 4-nitroaniline.It was proven that the addition of sodium hydroxide to aqueous 2-propanol solutions leads tothe increase of the observed reaction rate, and the addition of acetic acid – to its decline. Itwas noted that in the presence of additives, the rate of the hydrogenation reaction was notproportional to the adsorption of the 4-nitroaniline.The change of the reaction rate of the hydrogenation of 4-nitroaniline on skeletal nickel inaqueous 2-propanol solutions in the presence of additives is associated with the difference inthe reactivity of the adsorbed hydrogen. It was established that in the reduction of4-nitroaniline the -atomic form of the adsorbed hydrogen is more active.212