Development of pillared modified bentonite catalysts for catalysis of Friedel-Crafts alkylation of diphenylamine with nonene

In this study, we report the catalytic alkylation of diphenylamine with nonene using a series of acid-modified bentonite catalysts (Al-bent, Al/Fe-bent, and Al/Zn-bent) to overcome the drawbacks of traditional catalysts for diphenylamine alkylation. The catalysts were characterized by SEM, XRD, FTIR, and XRF analyses. Key reaction parameters including catalyst dosage, molar ratio of reactants, reaction time, and temperature were systematically optimized. The Al/Zn-bent catalyst exhibited the highest activity, achieving approximately 98% conversion of diphenylamine with high selectivity toward di-nonyl-diphenylamine under the optimal conditions (catalyst dosage of 15 wt%, diphenylamine (DPA) to nonene (NON) molar ratio of 1:6.0, reaction temperature of 150 °C, and reaction time of 18 h). Additionally, the catalyst demonstrated satisfactory reusability over four consecutive cycles, which verifies its unique structural advantages and confirms its potential as an efficient, sustainable and regenerable heterogeneous catalyst for this alkylation reaction.