Hydrogenation of diethyl maleate in a fixed-bed catalytic reactor: kinetics, reactor modelling and pilot plant studies

Abstract

Hydrogenation of diethyl maleate using copper chromite catalyst was investigated in a fixed-bed reactor with the aim of kinetic modelling and reactor performance studies. The effect of contact time (W/F), hydrogen pressure (1-5 MPa), and feed composition on the global rate of hydrogenation and selectivity was studied. The main products formed were γ-butyrolactone (GBL), tetrahydrofuran (THF), diethyl succinate (DES) and 1,4 butanediol (BDO), but the selectivity of THF was higher in comparison to GBL and BDO in most cases. The results at d_P<600 μm were found to be in kinetic regime and both intraparticle and external mass transfer resistances were negligible, but for d_P>3 mm, intraparticle diffusion effects were found to be important. Based on the integral reactor data, the rate equations have been proposed for various reaction steps assuming single site L-H-type mechanism. Hydrogenation experiments were also carried out on a pilot plant scale (1.5 kg catalyst capacity) and the reactor performance was found to agree reasonably well with the predictions of a theoretical model.