Vapor-phase catalytic dehydration of 2,3-butanediol (2,3-BDO) was investigated over rare earth oxide catalysts and In2O3 at around 400 degrees C. In the dehydration of 2,3-BDO over SC2O3, 1,3-butadiene was mainly produced together with butanone, 2-methyl-propanal, 2-methyl-propanol,3-buten-2-ol, and butene isomers. SC2O3 calcined at 800 degrees C showed the highest 1,3-butadiene yield of 88.3% at 411 degrees C in H-2 carrier gas flow. Since 3-buten-2-ol is produced selectively from 2,3-BDO over Sc2O3 at a low temperature of 325 degrees C, 3-buten-2-ol rather than butanone is a probable intermediate from 2,3-BDO to 1,3-butadiene. 3-Buten-2-ol is readily converted into 1,3-butadiene at temperatures lower than 411 degrees C over Sc2O3 and Al2O3. In addition, double-bed catalysts composed of an upper catalyst bed of Sc2O3 and a lower of Al2O3 successfully converted 2,3-BDO directly into 1,3-butadiene with a stable selectivity higher than 94% at 318 degrees C and 100% conversion of 2,3-BDO. (C) 2014 Elsevier B.V. All rights reserved.