Pd Nanoparticles-Loaded Vinyl Polymer Gels: Preparation, Structure and Catalysis

Abstract

Four vinyl polymer gels (VPGs) were synthesized by free radical polymerization of divinylbenzene, ethane-1,2-diyl dimethacrylate, and copolymerization of divinylbenzene with styrene, and ethane-1,2-diyl dimethacrylate with methyl methacrylate, as supports for palladium nanoparticles. VPGs obtained from divinylbenzene and from divinylbenzene with styrene had spherical shapes while those obtained from ethane-1,2-diyl dimethacrylate and from ethane-1,2-diyl dimethacrylate with methyl methacrylate did not have any specific shapes. Pd(OAc)2 was impregnated onto VPGs and reduced to form Pd0 nanoparticles within VPGs. The structures of Pd0-loaded VPGs were analyzed by XRD, TEM, and nitrogen gas adsorption. Pd0-loaded VPGs had nanocrystals of Pd0 within and on the surface of the polymeric supports. Pd0/VPGs efficiently catalyzed the oxidation/disproportionation of benzyl alcohol into benzaldehyde/toluene, where activity and selectivity between benzaldehyde and toluene varied, depending on the structure of VPG and the weight percentage loading of Pd0. The catalysts were stable and Pd leaching to liquid phase did not occur. The catalysts were separated and reused for five times without any significant decrease in the catalytic activity.

Dielectric Permittivity, AC Electrical Conductivity and Conduction Mechanism of High Crosslinked-Vinyl Polymers and Their Pd(OAc)2 Composites

“…Poly(ethylene-1,2-diyl dimethacrylate) (poly(EDMA)) and poly(ethylene-1,2-diyl dimethacrylate-co-methyl methacrylate) (Poly(EDMA-co-MMA)) were prepared according to the procedure described in our previous work [25] by free radical polymerization of EDMA monomer and copolymerization of EDMA and MMA monomers using AIBN as the initiator in the presence of THF as the solvent (Scheme 1A). To prepare poly(EDMA), a two-necked round bottom flask (200 mL) connected with a condenser was charged with AIBN (0.082 gm, 0.5 mmol), evacuated, and filled with nitrogen gas three times.…”

“…The yield of poly(EDMA-co-MMA) was 7.95 gm (>99%) as a white solid crystal. Pd(OAc)2 was loaded on poly(EDMA) and poly(EDMA-co-MMA) by soaking polymeric materials in a solution of Pd(OAc)2 in methanol according to the procedure de- Pd(OAc) 2 was loaded on poly(EDMA) and poly(EDMA-co-MMA) by soaking polymeric materials in a solution of Pd(OAc) 2 in methanol according to the procedure described in our previous work [25] (Scheme 1B). Each polymer, poly(EDMA) and poly(EDMA-co-MMA), (150 mg) was added to a solution of Pd(OAc) 2 (10 mg, 0.044 mmol) in methanol (50 mL) and stirred for 12 h to allow Pd(OAc) 2 molecules to go deep within the polymer matrices.…”

“…The loaded amount of Pd(OAc) 2 which was immobilized on poly(EDMA) and poly(EDMA-co-MMA) was determined by gravimetry after washing and drying the composites and was found to be 5.1% and 1.6% of the weight of poly(EDMA) and poly(EDMA-co-MMA), respectively. The structure and chemical properties of poly(EDMA), poly(EDMA-co-MMA) and their Pd composites were discussed in detail in our previous paper [25].…”

“…In our previous work, Pd nanoparticles were loaded on Poly(ethylene-1,2-diyl dimethacrylate) (poly(EDMA)) and poly(ethylene-1,2-diyl dimethacrylate-co-methyl methacrylate) (Poly(EDMA-co-MMA)) and applied as a heterogenous catalyst for the oxidation of benzyl alcohol to benzaldehyde and toluene. The formed Pd-polymer catalysts were characterized by XRD, TEM, and nitrogen gas adsorption [25].…”

Silver Nanoparticles Immobilized on Crosslinked Vinyl Polymer for Catalytic Reduction of Nitrophenol: Experimental and Computational Studies

“…In addition, silver nanoparticles are thermodynamically unstable and easy to form aggregations which decrease their catalytic activities [34]. These limitations could be overcome by loading them on suitable solid supporters which including inorganic materials such as zeolite, silica gel, metal oxide, and activated carbon [35][36][37][38][39][40] as well as organic materials such as porous organic polymers [41,42]. Although inorganic supporting materials loaded with metal nanoparticles perform well, their structural variations are rather limited [43].…”