N-maleyl chitosan-supported palladium catalyst for Heck coupling reaction and reduction of 4-nitrophenol

In this study, maleic anhydride-acylated chitosan (MAAC) was synthesized by modifying chitosan with maleic anhydride, and used to support palladium catalysts. N-maleyl chitosan-supported palladium (Pd/MAAC) was used as a heterogeneous catalyst for the Heck coupling reaction and reduction of 4-nitrophenol (4-NP). The chemical structure of Pd/MAAC was characterized using FT-IR XPS, XRD, XPS, TEM, SEM/EDS, N-2-physisorption (adsorption-desorption), and ICP-MS. The as-synthesized catalyst exhibited high catalytic performance and could be reused up to nine runs to catalyze the cyclic reaction between iodobenzene and n-butyl acrylate with low leaching of palladium. Pd/MAAC was also used for the reduction of 4-NP to 4-aminophenol(4-AP) in 90 s at room temperature, and could be reused six times. The findings establish that Pd/MAAC catalyst is an efficient, economical, practical, and environment-friendly catalyst for the Heck reaction and reduction of 4-NP.