Palladium/Alginate/Poly(NIPAM) Beads with Thermally Tunable Hydrophobic–Hydrophilic Domains for Nitroarene Reduction Reactions in Aqueous Media
Organic Process Research and Development, vol.30, no.6, pp.1634-1641, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 30 Issue: 6
- Publication Date: 2026
- Doi Number: 10.1021/acs.oprd.6c00065
- Journal Name: Organic Process Research and Development
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Compendex
- Page Numbers: pp.1634-1641
- Keywords: 4-nitrophenol, alginate, hydrogenation, palladium, thermoresponsive polymers
- Hacettepe University Affiliated: Yes
Abstract
This study introduces a thermoresponsive hybrid hydrogel catalyst that integrates a poly(N-isopropylacrylamide) (poly(NIPAM)) core, palladium catalytic centers, and a biobased alginate shell to enable efficient aqueous-phase reduction of nitroarene derivatives. Core–shell alginate gel beads were successfully fabricated above the lower critical solution temperature (LCST) of poly(NIPAM), yielding a structurally robust and hierarchically organized catalytic architecture. Upon thermal activation at 50 °C, the poly(NIPAM) core undergoes a reversible phase transition that generates hydrophobic domains in situ, markedly enhancing the partitioning and diffusion of hydrophobic reactants toward the embedded catalytic sites in an otherwise aqueous environment. Catalytic activity was assessed using 4-nitrophenol as a model substrate, achieving a high turnover number of 9100 and a turnover frequency of 27,324 h–1 at 50 °C. Moreover, the catalyst demonstrates broad substrate tolerance across both hydrophilic and hydrophobic nitroarene derivatives, while maintaining excellent physical integrity and reusability for at least five catalytic cycles. Collectively, these results underscore the significance of coupling thermoresponsive polymer physics with renewable biopolymer scaffolds to create adaptive, robust, and eco-friendly catalytic systems, offering a general strategy for sustainable catalysis under green reaction conditions.