Reaction of glyoxal with aliphatic alcohols using cationic exchange resins as catalysts

Abstract

The applicability of cationic exchange resins, such as Indion 130, Amberlyst-15, and Amberlite IR-120, as catalysts was evaluated for the reactions of glyoxal with different aliphatic alcohols to give mono- and diacetals. The alcohols studied in the present work were methanol, n-butanol, isoamyl alcohol, and 2-ethylhexanol. In all cases, the presence of water in the reaction mixture was found to have a strong impact on the equilibrium conversion and the reaction kinetics. The removal of water results in a significant enhancement in the conversion levels. Reaction parameters such as mole ratio of reactants, temperature, and catalyst loading were studied to maximize the selectivity towards the industrially more important product, i.e., monoacetals of glyoxal. Experimental data for the batch reactions of methanol are very well explained by a simple pseudohomogeneous model. A simplified lumped parameter model, consisting of four parameters, based on the Langmuir-Hinshelwood-Hougen-Watson mechanism, has been proposed for the reactions of glyoxal with less reactive alcohols (n-butanol, isoamyl alcohol, and 2-ethylhexanol), as the effect of water concentration on the kinetics of these reactions cannot be explained by a pseudohomogeneous model.