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Autori: E. Angelescu, M. Che, M. Andruh, R. Zãvoianu, G. Costentin, C. Miricã, O.D. Pavel
Editorial: Journal of Molecular Catalysis A: Chemical, 219, p.13-19, 2004.
The activity and selectivity of several catalysts based on Ni(4,4′-bipyridine)Cl2 complex co-activated with AlCl(C2H5)2 and supported on different molecular sieves such as Y, L, mordenite, mesoporous MCM-41 and on amorphous silica–alumina utilised in the dimerization of ethylene at 298 K and initial pressure of the monomer 12 atm is presented. Chemo- and stereo-selectivity effects expressed as selectivity for dimers and oligomers, and respectively, the concentration of 1-C4H8 in C4H8 fraction and the molar ratios 2-trans-C4H8/2-cis-C4H8 are discussed. The results are correlated with the steric and diffusion hindrances induced by the micro- and meso-porous structure respectively, of the porous solid matrix.
The polymer complex Ni(4,4′-bipyridine)Cl2 co-activated with AlCl(C2H5)2 and dispersed on micro- or mesoporous supports is an active and selective catalyst for ethylene dimerization to normal butenes under mild reaction conditions. The complex supported on MCM-41 molecular sieve exhibited the highest activity and allowed also the obtaining of highest amounts of oligomers.
Cuvinte cheie: Ethylene dimerization; Encapsulated complex catalysts; Ni(4,4′-bipyridine)Cl2-AlCl(C2H5)2; Microporous and mesoporous matrix