Vapour-phase dehydration of 1,4-butanediol (1,4-BDO) presents a sustainable route to valuable chemicals such as tetrahydrofuran (THF), 1,3-butadiene (BD), and light olefins (ethylene, propylene). Given their significance in synthetic rubber, plastics, and solvents, developing efficient catalytic processes for their sustainable production is crucial. This study investigates the chemo-catalytic conversion of 1,4-BDO to value-added products in presence of MFI-type HZSM-5 zeolite catalysts in an atmospheric-pressure operated downflow fixed-bed reactor. Strong Brønsted acid sites in HZSM-5, determined via temperature-programmed analysis, promoted tetrahydrofuran (THF) as major product at lower temperatures (close to 95% selectivity). Selectivity to second dehydration products such as BD and propylene were influenced greatly by temperature and weight hour space velocity (around 40% combined selectivity observed at 723 K and 0.43 h-1 WHSV). The selectivity to products varied with Si/Al mole ratio of HZSM-5 species as well, as the B/L acid site ratio, examined by pyridine-FTIR analysis, altered with change in Si/Al mole ratio. Thermodynamic analysis via process modelling, and detailed kinetic study were also performed. The control experiments performed in lab-scale experiments suggested metal sites in HZSM-5 facilitated undesired dehydroformylation side reactions, leading to competitive propylene formation. To mitigate this, basic modifications were implemented to neutralize metallic sites, optimizing BD selectivity.
