Selective partial hydrogenation of 1, 3-Dinitrobenzene over ni on activated carbon fibers

Abstract

Consulta en la Biblioteca ETSI Industriales (Riunet)

[EN] This work has reported, for the first time, 95% yield of m-nitroaniline (m-NA) in the liquid phase hydrogenation (T = 423 K; P = 20 bar) of m-dinitrobenzene over a carbon-supported catalyst based on structured activated carbon fibers (ACF) monodispersed (2 nm) poly(N-vinyl-2-pyrrolidone)-stabilized nickel nanoparticles (NPs). The experimental measurements have been adequately represented by a kinetic model based on a Langmuir-Hinshelwood mechanism. The impact of PVP-removal by means of UV-ozone and pyrolysis treatments has been assessed where increased activity and selectivity to the target product have been achieved with the first procedure. This could be attributed to the fact that the temperature used in the pyrolysis is not enough to break the polymer carbon bonds. The reaction shows antipathetic structure sensitivity, i.e. increased (by a 6-fold) TOF over larger (from 2 ¿ 14 nm, confirmed by high resolution transmission electron microscopy) Ni NPs with no significant differences in terms of selectivity (±3) to the target m-NA product. Solvent effects have been studied because the TOF and selectivity of m-NA exhibited a marked dependency on the nature of the reaction medium consistent with the following increased selectivity sequence: methanol > ethanol > propanol > butanol > hexanol > THF. This response has been attributed to differences in the solvent polarity (from 33 in methanol to 7.6 in THF). Under similar reaction conditions, a benchmark (oxide supported) Ni/Al2O3 shows significant lower activity and selectivity to the target m-NA. The results of this work demonstrate the potential of Ni/ACF as an effective catalyst formulation for the clean production of functionalized anilines.