Continuous Hydrogenation of 2-Butyne-1,4-diol to 2-Butene- and Butane-1,4-diols

Continuous catalytic hydrogenation of 2-butyne-1,4-diol (B 3 D) was carried out in a fixed-bed reactor over 1% Pt/CaCO 3 catalyst to give 2-butene-1,4-diol (B 2 D) and butane-1,4-diol (B 1 D) without formation of any other side products. In case of continuous hydrogenation, higher selectivity (66%) to B 2 D could be obtained and the selectivity pattern was completely different from that found in case of batch slurry operation in which B 1 D selectivity was very much higher (83%) than the B 2 D selectivity (17%). Another interesting feature was that by varying the contact time, the selectivity to both B 2 D as well as B 1 D could be varied over a wide range which is an attractive option to obtain the desired products mix of B 1 D and B 2 D, 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.