SHS Membrane for the Dehydrogenation of n-Butanol to Butadienes

Abstract

We have synthesized catalytically active membranes based on α- and γ-Al₂O₃ powders for the dehydration and dehydrogenation of butyl alcohol to butadiene and hydrogen. The open porosity of the samples obtained in this study is 41% in the case of α-Al₂O₃ and 38% in the case of γ-Al₂O₃. The open pore size is 4.6–5.1 μm in the α-Al₂O₃ material and 0.5–0.8 μm in the γ-Al₂O₃ material. We have implemented a hybrid, membrane–catalytic process for the dehydrogenation of butanol by combining reaction and hydrogen separation steps in a single device. It has been demonstrated that the dehydration of n-butanol on a γ-Al₂O₃ converter leads to the formation of a butylene fraction with a selectivity of 99.88–100% at a temperature of 300°C, which is 50°C lower than in the case of commercially available gamma-alumina granules. The dehydrogenation of butylene to butadiene on an α-Al₂O₃ membrane with selective hydrogen removal from the reaction zone has made it possible to raise the 1,3-butadiene output from 16.5 to 22.6 L/(h g_{act. comp.}), with the degree of ultrapure hydrogen extraction reaching ~16%. After the experiment was run for 20 h, no decrease in the catalytic activity of the system was detected, as distinct from commercial solutions, in which a regeneration step is necessary every 8–15 min.