3 resultados para Lee, Jason

em Aston University Research Archive


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Book review: CIUTI-Forum Paris 2005: Regards sur les aspects culturels de la communication. Martin Forstner and Hannelore Lee-Jahnke (eds). Bern: Peter Lang, 2006. xii + 307 pp. ISBN 978-3-03910-834-4.

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Robust, bifunctional catalysts comprising Rh(CO)(Xantphos) exchanged phosphotungstic acids of general formulas [Rh(CO)(Xantphos)]+n[H3–nPW12O40]n− have been synthesized over silica supports which exhibit tunable activity and selectivity toward direct vapor phase methanol carbonylation. The optimal Rh:acid ratio = 0.5, with higher rhodium concentrations increasing the selectivity to methyl acetate over dimethyl ether at the expense of lower acidity and poor activity. On-stream deactivation above 200 °C reflects Rh decomplexation and reduction to Rh metal, in conjunction with catalyst dehydration and loss of solid acidity because of undesired methyl acetate hydrolysis, but can be alleviated by water addition and lower temperature operation.

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A novel compound comprising a Ru–tethered polyoxometallate Keggin anion of formula [HNEt3]+[(Ru{η5-C5H5}{PPh3}2)2(PW12O40)]− has been synthesised that shows high activity and selectivity in alkyne oligomerisation. In situ IR binding studies using CO confirmed the accessibility of the Ru centre for catalysis. Phenyl acetylene was successfully dimerised under a heterogeneous catalytic regime. Selectivity towards the (E)-enyne, not found in the homogeneous Ru(η5-C5H5)(PPh3)2Cl analogue, was achieved while retaining high a turnover frequency of 225 h−1.