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

Flow-Through Catalytic Reactors Based on Metal Nanoparticles Immobilized within Porous Polymeric Gels and Surfaces/Hollows of Polymeric Membranes

“…It is seen that after cyclic exploitation of hollow membrane during 3 h the conversion of 4-NP decreases up to 60%, the initial structure of membrane changes (probably due to fouling), the fine distributed gold nanoparticles probably aggregate and by-products are deposited on the surface of membrane. Such phenomenon was also observed in the case of cryogel catalyst [41]. As distinct from PES-PSS/PAH/AuNPs the PS-PSS/PAH/AuNPs holds the activity at the level of 95-98% with minimal leaching of Au (<5 ppb) during the 4h of reaction.…”

“…Porous P(DMAEM-co-MAA) cryogel with immobilized AuNPs was used as a flow-through catalytic reactor in reduction of 4-NP and oxidation of D,L-dithiotreitol (DTT) [38][39][40]. The final hydrogenation product of 4-NP is 4-AP, while the final oxidation product of DTT is disulfide (DS).…”

“…The kinetic parameters, turnover number (TON), turnover frequency (TOF) and activation energy of hydrogenation of 4-NP and oxidation of DTT were determined in these experiments ( Table 2). The catalytic reduction of p-nitrobenzoic acid (p-NBA) was performed by palladium (PdNPs) and gold nanoparticles (AuNPs) immobilized within P(DMAEM-co-MAA) cryogel matrix [41] (Figure 7). It should be noted that in the absence of immobilized metal nanoparticles the mixture of p-NBA and NaBH 4 fluxed through the P(DMAEM-co-MAA) cryogel does not produce p-aminobenzoic acid (p-ABA) [42].…”

Physicochemical, Complexation and Catalytic Properties of Polyampholyte Cryogels

“…The catalytic reduction of 4-NP by NaBH 4 and oxidation of d , l -dithiotreitol (DTT) by hydrogen peroxide in the presence of AuNPs supported on a cryogel matrix of P(DMAEM- co -MAA) was evaluated, and the kinetic parameters, turnover number (TON), turnover frequency (TOF) and activation energy of hydrogenation of 4-NP have been calculated [65,66,67,68].…”

“…The average size of AuNPs accumulated in both surface and longitudinal parts of the cryogel was less than 100 nm. Moreover, the partial leaching out of AuNPs was observed over the course of reduction of sequental portions of substrate [68]. In reduction of 4-NP, the values of TON and TOF of the cryogel catalyst are equal to 38.17 and 21.56 h −1 respectively.…”