新型催化剂-科学网.DOCVIP

新型催化剂 06 November 2007The largest transition metal-catalysed process in the chemical industry could soon get an efficiency boost, thanks to the isolation of a key catalytic intermediate.UK chemists have made a new series of catalysts in an effort to up the efficiency of one of the most widely used, and energy-intensive, catalytic processes in the chemical industry - the conversion of carbon monoxide (CO) and methanol into acetic acid. Matthew Clarke and colleagues at St Andrews University, UK, have examined a series of diphosphine ligands in the rhodium-catalysed carbonylation of methanol. This is one of the simplest organic reactions there is, but because of the scale, it must be done so incredibly efficiently, said Clarke.The industrial process used currently, BPs Cativa process, requires the starting CO to be purified, and the final product to be distilled - both of which are energy-expensive processes. Now BP is funding a project to look for the next generation of catalyst to get around either, or both, of these drawbacks.Cheaper, lower grade CO includes large amounts of hydrogen, so to use it you need a catalyst that reacts with the CO but not the hydrogen, said Clarke. We identified a ligand, dppx [tetrakis(diphenylphosphino)-p-xylene], that was very selective, he said. We isolated the catalytic intermediate, and showed it doesnt react with hydrogen, where the others do, so this is likely to be the origin of the selectivity.Were already making new catalysts based on this work, trying to gain a rational understanding of the selectivity- Matthew Clarke, St Andrews University, UKWere already making new catalysts based on this work, trying to gain a rational understanding of the selectivity, Clarke added. We havent cracked it yet, but I have an inkling there is a ligand out there that is active, selective, stable and commercially viable. Andreas Danopoulos, who studies catalysis at the University of Southampton, UK, said the work was a good approach to un