Architecture of bimodal porous CuO/Al2O3-controlled continuous and low-temperature production of biomass-derived γ-butyrolactone

Abstract

Biomedical activities of gamma butyrolactone (GBL) play an important role in the development of novel physiological and therapeutic agents. Maleic anhydride catalytic liquid phase hydrogenation allows for selective synthesis of GBL. However, this process is hampered by high cost noble metals and high reaction pressure conditions. Here, we demonstrate cyclic dehydrogenation of biomass-derived 1,4-butanediol (1,4-BDO) under atmospheric pressure and low-temperature conditions using highly dispersed and chemically stabilized Cu species on bimodal porous Al2O3. The bimodal porous Al2O3 exhibited both Lewis and Brønsted acidic properties along with high specific surface area and large pore volume. Among prepared catalysts, 15 wt% Cu/Al2O3 catalyst has shown an optimal crystallite size, bimodal porous nature, and high diffusion properties. Hence, high catalytic activity and remarkable GBL yields with very high 1,4-BDO conversion for 50 h of continuous time-on-stream. The unique bimodal textural properties help to enhance the dehydrogenation activity with a high turnover frequency (TOF) of about 5.0118 x 10-3 s-1via efficient chemical interaction between metallic Cu and 1,4-BDO molecules.