Continuous hydrogenation of 2-butyne-1,4-diol to 2-butene- and butane-1,4-diols

Abstract

Continuous catalytic hydrogenation of 2-butyne-1,4-diol (B₃D) was carried out in a fixed-bed reactor over 1% Pt/CaCO₃ catalyst to give 2-butene-1,4-diol (B₂D) and butane-1,4-diol (B₁D) without formation of any other side products. In case of continuous hydrogenation, higher selectivity (66%) to B₂D could be obtained and the selectivity pattern was completely different from that found in case of batch slurry operation in which B₁D selectivity was very much higher (83%) than the B₂D selectivity (17%). Another interesting feature was that by varying the contact time, the selectivity to both B₂D as well as B₁D could be varied over a wide range which is an attractive option to obtain the desired products mix of B₁D and B₂D, depending on the fluctuation in the market demand. Further, a mathematical model for reactor performance was also developed on the basis of the kinetic data obtained previously in a batch slurry reactor. The predicted values of conversion, selectivity, and rate of hydrogenation were found to agree with the experimental data over a wide range of conditions.