Global supply of 1,3-butadiene (abbreviated as BD) is faced with problems such as unstable price of petrochemicals and variation of chemical feedstock in recent years. Many research works have been conducted to produce BD from some renewable resources instead of petroleum. Among them, biomass-derived C 4 alcohols such as 1,3-butanediol (1,3-BDO), 2,3-butanediol (2,3-BDO), and 1,4-butanediol (1,4-BDO) have been considered as alternative resources to produce BD. Direct dehydration of butanediols (BDOs) into BD, however, needs high reaction temperatures while the dehydration into their corresponding unsaturated alcohols (UOLs) such as 3-buten-2-ol (3B2OL), 2-buten-1-ol (2B1OL), and 3-buten-1-ol (3B1OL) proceeds at rather low temperatures over specific catalysts. The latter step of BDO dehydration, dehydration of UOLs to BD, is readily catalyzed by solid acids even at lower temperatures than those at which BDOs are dehydrated completely. Thus, efficient formation of UOLs from BDOs would be a key process to produce BD with high selectivity. We summarize the BD production from C 4 alcohols as well as the dehydration of BDOs to UOLs, in addition to the BD production via ethanol dimerization.

No abstract

No abstract

Vapor-phase catalytic dehydration of 2,3-butanediol (2,3-BDO) was investigated over several metal oxides loaded on well-crystallized monoclinic ZrO 2. In the dehydration of 2,3-BDO, unsaturated alcohol, i.e. 3-buten-2-ol (3B2OL), was preferentially produced together with major by-products such as butanone and 3-hydroxy-2-butanone over ZrO 2-based catalysts. The selectivity to 3B2OL over monoclinic ZrO 2 was greatly enhanced by the alkaline-earth oxides such as CaO, SrO, and BaO. At a CaO loading of 3 wt.% on the monoclinic ZrO 2 , a Ca-O-Zr hetero-linkage was formed to generate new basic sites, and the selectivity to 3B2OL exceeded 76% at 350 o C. Poisoning experiments using CO 2 and NH 3 strongly suggest that the formation of 3B2OL from 2,3-BDO proceeds over base-acid concerted sites.

No abstract