Competitive hydrogenation in binary diene systems on a palladium catalyst 

Abstract

Hydrogenations of individual C 5 dienic substrates (1,3-cyclopentadiene, isoprene, 1,4-pentadiene, cis-1,3-pentadiene, trans-1,3-pentadiene) and their binary mixtures on a heterogeneous palladium catalyst were studied in cyclohexane at 25°C and 2 MPa. Selectivities of the competitive hydrogenations were determined and the substrates relative adsorption coefficients calculated. Effects of the diene structure on their reactivity and the stability of the surface complex are discussed. It was found that differences in selectivity of the competitive hydrogenations of C 5 dienes are caused by the difference both in adsorptivity values and in reactivity of adsorbed molecules. The presence of a five-membered ring in the C 5 dienes leads to significant reduction of surface complex stability as compared with acyclic structures of C 5 dienes. On the other hand, it has a very positive effect on the rate of surface reaction.

Evaluation of Benzylamine Production via Reductive Amination of Benzaldehyde in a Slurry Reactor

“…On the other hand, it was stated that washing the fresh catalyst with benzylamine did not suppress benzyl alcohol formation in the subsequent reaction. From these facts it can be concluded that, in reductive amination of aromatic carbonyl compounds, unsaturated N-containing intermediates, i.e., differently coordinated primary imines and nitrene [6,19,[29][30][31][32][33], adsorb on the Ni catalyst surface stronger than the aldehyde, and thus restrict hydrogenation of the aldehyde to the alcohol (Scheme 4).…”

“…Competition of reactants and reaction intermediates for the nickel catalyst surface in benzaldehyde amination. Structure of surface intermediates adapted from studies[6,19,33].…”

Experimental Methods for Developing Kinetic Models for Hydrocracking Reactions with Slurry-Phase Catalyst Using Batch Reactors

“…While the most studied hydrogenation reactions are the saturation of olefins and aromatics. 51 Hydrocracking and hydrogenation reactions can occur to different extents depending on the operating conditions. At moderate temperature (≤410 °C), hydrogenation reactions dominate, but at high temperature (>410 °C) hydrocracking reactions are predominant.…”

Chemo‐selective reduction of nitro and nitrile compounds using Ni nanoparticles immobilized on hyperbranched polymer‐functionalized magnetic nanoparticles

“…[37,38] In these cases, a variety of transition metals including Co, Ni, Au, Cu, Rh, Pd and Pt have been immobilized on different supports (C, TiO 2 , SiO 4 , Al 2 O 3 and so on), displaying a high potential towards the facile reduction of nitrile/nitro compounds using various reducing agents, such as H 2 , NaBH 4 , N 2 H 4 ⋅H 2 O and so on. [39][40][41][42][43][44][45][46] These catalytic systems constitute a major task for the development of green synthetic methodologies and are of importance in organic chemistry. Recently, extensive studies have been done on the reduction of nitrile/nitro compounds to corresponding amine derivatives using low-cost non-noble metals (e.g.…”