Catalytic vapor-phase cyclization of 1,6-hexanediol into cyclopentanone

CeO2-based binary oxides catalyzed the cyclization of 1,6-hexanediol into cyclopentanone at temperatures of 400-475 degreesC. CeO2-based solid solution with Mn content of 20 mol% shows the highest catalytic activity, both conversion and selectivity, while both pure CeO2 and Mn2O3 have the cyclization ability of 1,6-hexanediol. Cyclopentanone is produced with the maximum selectivity of 80.9 mol% over CeO2-MnOx solid solution catalyst at 450 degreesC. As byproducts, cyclohexanone, cyclopentylmethanol, 1-hexanol, and hexanal are observed in the cyclization. Low concentration of 1,6-hexanediol would be preferable in the catalytic operation because dimerized products are observed at high concentration of 1,6-hexanediol. (C) 2003 Elsevier B.V. All rights reserved.