Vapor-phase catalytic reactions of several terminal diols were investigated over several rare earth oxides, such as Sc(2)O(3), Y(2)O(3), CeO(2), Yb(2)O(3), and Lu(2)O(3). Sc(2)O(3) showed selective catalytic activity in the dehydration of terminal diols with long carbon chain, such as 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol, to produce the corresponding unsaturated alcohols. In the dehydration of 1,6-hexanediol, 5-hexen-1-ol was produced with selectivity over 60 mol%, together with by-products such as epsilon-caprolactone and oxacycloheptane. In the dehydration of 1,10-decanediol, 9-decen-1-ol was produced with selectivity higher than 70 mol%. In addition to Sc(2)O(3), heavy rare earth oxides such as Lu(2)O(3) as well as monoclinic ZrO(2) showed moderate selectivity in the dehydration of the terminal diols. (C) 2010 Elsevier B. V. All rights reserved.