Design of zeolite catalysts for nitroaldol reaction under mild condition

NaY and KL zeolites were modified by impregnating with potassium fluoride for investigating their basicity and catalytic activity towards Henry nitroaldol reaction under different reaction conditions. Effects of solvents, temperature, catalysts and ratio of substrate versus reagents were studied to optimize the reaction conditions. The catalysts were characterized by FTIR, XRD and SEM techniques and the products were characterized by 1H NMR, 13C NMR and FTIR techniques. It was observed that NaY/KF zeolite with H2O–MeOH pair as solvent showed good conversion and selectivity at room temperature. Both XRD and FTIR study showed no change of spectral patterns for both modified and parent zeolites. We have again showed a plot of Hammett free energy linear relationship in terms of percentage yield and Hammett substituent constant.

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► Henry nitroaldol reaction conditions were optimized with moderately weak base catalysts under various reaction conditions.
► Basic zeolites NaY, KL and their alkali metal impregnated form are found to be effective catalysts for nitroaldol reaction.
► Framework structure of zeolites does not break after modification.
► The reaction gives nitroaldol product in good yield.