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Catalysis of ultrafine CuB catalyst for hydrogenation of olefinic and carbonyl groups

2000; Elsevier BV; Volume: 196; Issue: 2 Linguagem: Inglês

10.1016/s0926-860x(99)00464-0

1873-3875

Biing‐Jye Liaw, Y.Z Chen,

Nanoporous metals and alloys

Ultrafine catalysts of CuB and Me–CuB (Me: Cr, V, La, Th, Zn) were prepared by the chemical reduction method and were characterized. Their catalytic properties for hydrogenation on monofunctional (olefinic and carbonyl) and bifunctional (conjugated and nonconjugated) compounds were also studied and compared with those of a commercial catalyst of copper chromite. For the hydrogenation of monofunctional compounds over CuB catalyst, the reactivities were in the following order: CO (in aldehyde) > CO (in ketone) ⪢ CC. The reactivity of CC was largely enhanced by its delocalization with conjugated CC or CO group. In general, the additives of Cr, V, La, Th and Zn increased the dispersion of copper in CuB catalyst and promoted the reduction of CO group. The additive of Cr only slightly affected the reduction of monofunctional CC group, but effectively promoted the reduction of CO group. However, the additive of Cr also effectively promoted the reduction of CC group which was conjugated with CO or another CC group. The ultrafine catalysts of Cr–CuB containing a much lower content of chromium (Cr < 5 mol%) were more active than the commercial copper chromite (Cr > 50 mol%). These Cr–CuB catalysts are highly promising for replacing copper chromite for liquid-phase hydrogenation reactions.