(152bu) PDMS/polyamide imide-stabilized palladium nanaoparticles for hydrogenation of 4-nitrophenol

Catalytically active asymmetric membranes were developed by crosslinking a polydimethylsiloxane (PDMS) thin layer onto a porous polyamide‐imide hollow fiber (PAIHF) support, followed by grafting of aminosilane with hydroxyl derived-PDMS/PAIHF, and finally palladium nanoparticles (PdNPs) immobilization using salicylic aldehyde. Aminosilane and salicylic aldehyde linkers were used to permanently immobilize PdNPs onto the PDMS surface through metal coordination chelation, which prevented their agglomeration and leaching from the catalytic membrane reactor (CMR) module. The obtained CMRs were used as a heterogeneous catalyst and continuous-flow membrane reactor for hydrogenation of 4-nitrophenol. The obtained CMRs were used for hydrogenation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in a continuous-flow fashion. The effects of 4-NP concentration (0.5-4 mM) and flow rate (0.01-0.08 cm³min^-1) on 4-NP conversion and 4-AP selectivity were evaluated in both batch and continuous-flow systems. The newly developed continuous flow 4-NP hydrogenation module exhibited a good operating stability after four cycle run for 12 hours time on stream, where complete 4-NP conversion (100%) was achieved in short residence time (2-3 s) via a single-pass-through the CMR module.

This work was supported by the National Science Foundation Grant No. 2316143.