Application of polyaluminium chloride (PAC) as a Heterogeneous catalyst for glycerol formal synthesis

Department of Chemistry. Faculty of Mathematics and Natural Sciences, Universitas Islam Indonesia, Indonesia

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Abstract

Acetalization of glycerol with formaldehyde is one approach to produce glycerol formal compounds that have the potential to be used as fuel additives and environmentally friendly solvents. This study explores the use of polyaluminium chloride (PAC) as a heterogeneous catalyst in the acetalization reaction with a focus on its effectiveness in accelerating the reaction and product yield. Variations in reaction conditions studied include the molar ratio of glycerol : formaldehyde, PAC catalyst concentration, temperature, and reaction time. Characterization was carried out using GC- MS to identify the main products and evaluate the conversion of reactants. In addition, SEM-EDX was used to evaluate the surface conditions of PAC before and after the reaction. The results showed that PAC was able to activate the carbonyl group of formaldehyde through a Lewis acid mechanism, facilitating the formation of hemi-acetals and cyclic products. The optimum conditions were obtained at a ratio of 1:5, 1% PAC concentration, a temperature of 70°C, and a reaction time of 3 hours, with the main product being 1,3-dioxane-5-ol or glycerol formal. The use of PAC has been proven to be efficient and selective, and has the potential to be developed as an environmentally friendly heterogeneous catalyst in the synthesis of glycerol formal.