Hydrogenation of p -Nitrobenzoic Acid by Gold and Palladium Nanoparticles Immobilized Within Macroporous Amphoteric Cryogels in Aqueous Solution

Aqueous solutions of sodium salt of p-nitrobenzoic acid (p-NBA) were hydrogenated in mild conditions in the presence of palladium (PdNPs) and gold nanoparticles (AuNPs) immobilized within macroporous amphoteric cryogel based on N,N-dimethylaminoethylmethacrylate (DMAEM) and methacrylic acid (MAA). The morphology of the macroporous catalyst DMAEM-co-MAA/AuNPs was characterized using SEM. The pore sizes of sponge-like porous structure of cryogels are in the range of 5–40 µm, while the average sizes of AuNPs immobilized within the macroporous amphoteric cryogel are 80 ± 20 nm. The reduction of p-NBA to p-aminobenzoic acid (p-ABA) and further to by-products p,p′-azodibenzoate and sodium 4-(4-aminobenzamido)benzoate was confirmed by Raman and 1H NMR spectroscopy. The conversion degree, kinetic parameters, and activation energies of hydrogenation of p-NBA were found.