Schiff Base- and Imidazole-Functionalized Cellulose-Supported Pd Catalyst for 4-Nitrophenol Reduction and Suzuki Reactions

Cellulose is highly valuable due to its ready availability, biodegradability, and easy chemical modification. Recently, studies have focused on the chemical modification of cellulose and utilized it as a support for stabilizing metals. In this study, a Schiff base- and imidazole-functionalized cellulose-supported Pd (Cell-SB-IM-Pd) catalyst was prepared and used for the 4-nitrohpenol reduction as well as the synthesis of biaryls. Compared with the raw Cell-Pd catalyst (70%), Cell-SB-IM-Pd exhibited higher catalytic efficiency (90%) in Suzuki reactions, which was attributed to the introduction of C═N and imidazole, providing charge-transfer interaction between them and Pd. The Cell-SB-IM-Pd also showed good to excellent yields (up to 99%) for various substrates in Suzuki reactions under mild conditions. Likewise, we also demonstrated the stability and efficiency of Cell-SB-IM-Pd in the 4-nitrophenol reduction at room temperature in water, with an apparent rate constant of 9.074 × 10^-2 min^-1. This work provides more insights into the further utilization of cellulose as a Pd host matrix for converting organic pollutants and promoting sustainable chemical reactions.