Dehydration of butanediols into unsaturated alcohols was investigated over CeO2 with different particle sizes. The size was controlled by the calcination temperature. Catalytic performance in the dehydration of 1,3-butanediol is greatly affected by the particle size. The selectivity to unsaturated alcohols such as 3-buten-2-ol and trans-2-buten-1-ol increases with increasing the particle size, while decomposition of 1,3-butanediol into methanol and ethanol is catalyzed by CeO2 With small particles. In contrast, in the reaction of 1,4-butanediol, cyclization products such as tetrahydrofuran and gamma-butyrolactone increases with decreasing the particle size, instead of the decomposition into methanol and ethanol. CeO2 {111} facets became predominant on the large particles, whereas different surfaces such as {100} and {110} facets were exposed on the small CeO2 particles. In the dehydration of butanediols, CeO2 has structure-sensitive catalysis: CeO2 {111} facets have active sites for the formation of unsaturated alcohols, and the other surfaces catalyze the side reactions such as decomposition of 1,3-butanediol and cyclization of 1,4-butanediol. (c) 2005 Elsevier B.V. All rights reserved.