Selective acetylation of glycerol over CeO2–M and SO42?/CeO2–M (M = ZrO2 and Al2O3) catalysts for synthesis of bioadditives

The feasibility of acetylation of glycerol with acetic acid was investigated employing CeO₂–ZrO₂, CeO₂–Al₂O₃, SO₄^2?/CeO₂–ZrO₂, and SO₄^2?/CeO₂–Al₂O₃ solid acid catalysts to synthesize monoacetin, diacetin and triacetin having interesting applications as bioadditives for petroleum fuels. Intensive physicochemical and surface characterization of the prepared catalysts were performed using XRD, BET surface area, ammonia-TPD and Raman spectroscopy techniques. Characterization results revealed that impregnated sulfate ions strongly influence the physicochemical characteristics of the investigated mixed oxide catalysts. Among various catalysts investigated, the SO₄^2?/CeO₂–ZrO₂ combination catalyst exhibited superior catalytic activity under mild conditions. The effect of various parameters such as reaction temperature, molar ratio of acetic acid to glycerol, catalyst wt% and time-on-stream were studied over the SO₄^2?/CeO₂–ZrO₂ catalyst to optimize the reaction conditions. Catalyst reusability was also carried out to understand its stability.