2-CHLORO-4-NITROANILINE ADSORPTION ON ACTIVE CARBON FROM 2-PROPANOL SOLUTIONS

Abstract

Aromatic nitro compounds, such as nitro anilines and its halogen derivatives, are widely used in the industrial synthesis of dispersed azo dyes and some pharmaceutical products. For its preparation the processes of heterogeneous catalysis in various liquid media are used. One of the most important stages of catalysis, which in some cases determines its rate, is adsorption. The study of the nitro compounds adsorption from aqueous and non-aqueous solvents on the heterogeneous catalysts surface makes it possible to reveal the catalytic hydrogenation intimate mechanism features and the solvent influence on the hydrogenation process. In this work, we studied the 2-chloro-4-nitroaniline adsorption on active carbon from 2-propanol solutions at 293 and 313 K. Adsorption isotherms, two-dimensional state diagrams of the surface layers were obtained, and the isosteric heats of the process were calculated. The experimental adsorption isotherms are described in the framework of the volume filling of micropores for mesoporous adsorbents theory. The heat of adsorption is negative and decreases in absolute value with increasing degree of surface filling. On two-dimensional surface layers state diagrams the breaks presence, which corresponds to two-dimensional phase transitions, similar to second-order transitions in surface films. This fact indicates changes in the surface layers state with an increase in the degree of filling the coal surface with adsorbate, is observed.