Dehydrogenation of ethanol over CuO–Mg–Y for cross-aldol condensation with aryl aldehydes

Abstract

An economically viable approach for the synthesis of different α, β-unsaturated aldehydes through modified cross-aldol condensation reaction has been developed. In this synthetic process, acetaldehyde is generated in situ through the catalytic dehydrogenation of the ethanol. The dehydrogenation reaction is found to occur over copper oxide nanoparticles supported on magnesium exchanged zeolite-Y. The formation of acetaldehyde through dehydrogenation of ethanol is confirmed by the modified Hantzsch reaction. Different kinetic studies have been performed to predict the rate of acetaldehyde as well as cinnamaldehyde formation. The formation of α, β-unsaturated aldehydes through the dehydrogenative cross-aldol reaction of ethanol with various aldehydes are found to be dependent on different reaction parameters viz temperature, catalyst amount, time, and the nature of bases. The catalytic dehydrogenation process is found to occur within 80–100 °C. TDDFT calculations are used to correlate the electronic spectra of Hantzsch reaction product with the experimental one.