Unveiling activity of ZIF-8/ nickel loaded alumina aerogel catalyst in glycerol carbonate production from CO2 and glycerol

Abstract

Glycerol Carbonate (GC) production via carbonylation of glycerol with CO₂ reaction takes attention to its properties of enabling both the utilization of biodiesel by-product glycerol and the use of major greenhouse gas CO₂. Herein, the synthesis of GC via glycerol carbonylation with CO₂ over a series of ZIF-8 on nickel-loaded Alumina Aerogel catalysts was examined for the first time in literature. ZIF-8 growth on nickel-impregnated Alumina aerogel was executed using an in situ method. Synthesized catalysts were analyzed using SEM–EDX, FT-IR, DRIFTS, XRD, and N₂ sorption techniques. The carbonylation reaction of glycerol was conducted in the presence of a co-reactant (propylene oxide) and solvent (methanol). The influence of reaction parameters (temperature, catalyst loading, glycerol/co-reactant molar ratio, co-reactant type, catalyst type, and reaction time) on the catalytic activity (glycerol conversion, GC selectivity and yield) of the catalysts were investigated. It obtained high glycerol conversion (73%) for AA-2Ni-5ZIF, yield (31%), and selectivity (77%) of GC for AA-5Ni-15ZIF under optimized reaction conditions (150 °C, 7 bar, 2 h, 6% catalyst loading and 0.5 glycerol/propylene oxide). Compared to the literature, this activity was found under lower CO₂ pressure and reaction time. Unique features of catalysts such as suitable acidity, high surface area, more than one active crystal, and the presence of propylene oxide as a co-reactant promoted the rise of glycerol conversion, GC selectivity, and yield.