Silica-supported H3PW12O40 (PW) the strongest heteropoly acid in the Keggin series, is an efficient, environmentally friendly heterogeneous catalyst for the liquid-phase isomerization of alpha-pinene and longifolene into their more valuable isomers - camphene and isolongifolene, respectively, which are intermediates in the synthesis of expensive fragrances. The reactions occur under solvent-free conditions in the temperature range of 80-100 degrees C, with low catalyst loadings (0.15-5 wt%) and high turnover numbers (up to 6000 per proton). The catalyst can be easily recovered and reused. No PW leaching is observed in the reaction system. (C) 2008 Elsevier B.V. All rights reserved.
机构:
Univ York, Dept Chem, Clean Technol Ctr, York YO10 5DD, N Yorkshire, EnglandUniv York, Dept Chem, Clean Technol Ctr, York YO10 5DD, N Yorkshire, England
机构:
Univ York, Dept Chem, Clean Technol Ctr, York YO10 5DD, N Yorkshire, EnglandUniv York, Dept Chem, Clean Technol Ctr, York YO10 5DD, N Yorkshire, England