Jean Jenck

Gas - Liquid - Solid Reactors for Hydrogenation in Fine Chemicals Synthesis

Abstract Although the presence of a liquid phase in heterogeneous hydrogenation catalysis is useful for chemical reactivity control, it introduces considerable engineering complexity. Different types of triphasic hydrogenation reactors, with moving or immobilized catalyst, in continuous or batch mode, are compared. Coupling of intrinsic kinetics with mass and energy transfer determines reactor performances, in rate as well as in selectivity. Reactor design and scale-up require the knowledge of numerous physico-chemical parameters, whose acquisition by measurement or correlation is briefly presented.

Intermediates Formation in the Catalytic Hydrogenation of Nitriles

Abstract In the course of the catalytic hydrogenation of a,w dinitriles over Raney nickel, by-products are obtained from C-N and C-C bond formation. The mechanism of the formation of these compounds was investigated. Cyclic and linear secondary amines can result from the same secondary imine through a transimination process involving a ring-chain tautomerism. Stereochemical results for 2-aminomethyl-cyclopentylamine (AMCPA) are in accordance with a specific cyclisation pathway favored by an intramolecular hydrogen bond giving rise to the cis isomer from aminocapronitrile, unfavored in the case of adiponitrile which leads to the trans AMCPA as the major isomer.

Selective Hydrogenation of Adiponitrile (ADN) to Hexamethylenediamine (HMD) in the Liquid Phase on Raney Catalysts: Synergetic Effect Between the Base in the Solution and the Iron Dope on the Catalyst

Abstract This paper is devoted to the fundamental study of the doping effect of iron metal added to Ni-Al alloy precursor of Raney nickel catalysts. Their activities and selectivities in the liquid phase were determined taking into account the effect of the basicity of the solvent. The experiments were performed on catalysts coming from homogeneous NiAl 3 and Ni 2 Al 3 phases. A synergetic effect between the base in the solution and the iron dope in the catalyst was demonstrated.