Integrated conversion of 1-butanol to 1,3-butadiene

Renewed interest in production of 1,3-butadiene from non-petroleum sources has motivated research into novel production routes. In this study, we investigated an integrated process comprising 1-butanol dehydration over a γ-Al₂O₃ catalyst to produce a mixture of linear butenes, coupled with a downstream K-doped Cr₂O₃/Al₂O₃ catalyst to convert the butenes into butadiene. Linear butene yields greater than 90% are achievable at 360 °C in the dehydration step, and single-pass 1,3-butadiene yields greater than 40% are achieved from 1-butene in a N₂ atmosphere in the dehydrogenation step. In the integrated process, 1,3-butadiene yields are 10-15%. In all cases, linear C4 selectivity is greater than 90%, suggesting that 1,3-butadiene yields could be significantly improved in a recycle reactor. Doping the Cr₂O₃ catalyst with different metals to promote H₂ consumption in a CO₂ atmosphere did not have a large effect on catalyst performance compared to an undoped Cr₂O₃ catalyst, although doping with K in an N₂-diluted atmosphere and with Ni in a CO₂-enriched atmosphere showed slight improvement. In contrast, doping with K and Ca in a CO₂-enriched atmosphere showed slightly decreased performance. Similarly, employing a CO₂-enriched atmosphere in general did not improve 1,3-butadiene yield or selectivity compared to reactions performed in N₂. Overall, this study suggests that an integrated dehydration/dehydrogenation process to convert 1-butanol into 1,3-butadiene could be feasible with further catalyst and process development.