Improved processing stability in the hydrogenation of dimethyl maleate to γ-butyrolactone, 1,4-butanediol and tetrahydrofuran

摘要: Abstract In the hydrogenation of dimethyl maleate (DMM) to γ-butyrolactone (GBL), 1,4-butanediol (BDO) and tetrahydrofuran (THF), performance process can be negatively affected by (1) fouling plugging unit through deposition polymeric by-products (2) activity drop Cu/ZnO-based catalysts structural changes active copper phase at reaction conditions. On basis thermodynamic data, we calculated feed compositions required prevent condensation reactants subsequent formation polyester deposits in relevant temperature (453– 523 K ) pressure (1– 7 MPa regime. The resulting critical values minimum H2/DMM ratios feed, when corrected for capillary effects, were found excellent agreement with limits as experienced processing experiments. Conditions safe stable gas-phase DMM a single stage thus predicted. improved modifying thermal pre-treatment. As compared conventional materials same composition, they need less runtime reach stationary levels, their steady state activities are higher. yield ratio GBL BDO adjusted total because corresponding attains equilibrium. dehydration THF promoted applying higher temperatures; however, selectivities remain low over typical Cu/ZnO unless additional acid sites implemented.