Efficient production of 1,3-butadiene in the catalytic dehydration of 2,3-butanediol

•Catalytic dehydration of 2,3-butanediol was investigated for a direct formation of 1,3-butadiene.•Sc2O3 calcined at 800 °C was the most effective catalyst with high 1,3-butadiene selectivity.•1,3-Butadiene was preferentially produced over a single layer catalyst of Sc2O3 at 411 °C.•1,3-Butadiene was efficiently produced over two catalyst beds, Sc2O3 + Al2O3, at 318 °C.•The highest selectivity to 1,3-butadiene exceeds 94% at 318 °C.

Vapor-phase catalytic dehydration of 2,3-butanediol (2,3-BDO) was investigated over rare earth oxide catalysts and In2O3 at around 400 °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 °C showed the highest 1,3-butadiene yield of 88.3% at 411 °C in H2 carrier gas flow. Since 3-buten-2-ol is produced selectively from 2,3-BDO over Sc2O3 at a low temperature of 325 °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 °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 °C and 100% conversion of 2,3-BDO.

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