Sustainable Upgrade of Bioderived Glycerol to Solketal through Acetalization over Metal-Free Mordenite Catalysts

In the current work, acetalization of crude glycerol to produce valuable solketal, a renewable fuel additive, is studied over metal-free mordenite-based catalysts. The perfect combination of the appropriate acidity and suitable porosity is required to achieve optimum solketal yield from glycerol. The property–activity correlation was established through various physicochemical characterizations, and reaction parameters were optimized to maximize the solketal yield. The modified mordenite catalyst showed exceptionally high catalytic activity toward the acetalization of crude glycerol and as high as 99% yield of solketal was achieved under mild reaction conditions, i.e., a reaction temperature of 60 °C, a time of 4 h, and atmospheric pressure. The catalyst showed tolerance for water and other impurities present in crude glycerol in addition to excellent recyclability up to three cycles without any regeneration treatment. The economical, easy-to-prepare, recyclable, metal-free, moisture-tolerant nature of the catalyst makes it a promising catalyst candidate to be used at a larger scale. The catalytic process has the potential to utilize crude glycerol obtained from biodiesel plants for the synthesis of biofuel additives solketal. This highlights the industrial and environmental significance of this work.