الفهرس 
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Abstract
We have developed micro, mesopores H2N-PVBC polymer and report the first successful immobilization of catalytically active acidic Keggin-type phosphotungstic acid (H3PW12O40, PTA) and palladium nanoparticles (Pd-NP) materials on the surface and pores of H2N-PVBC framework. The Polymer-based catalysts are successfully prepared by carefully designing emulsion polymerization procedure of the DVB and VBC monomers, and then functionalized by diamine moieties (EDA or DAO or DDA) and Keggin units (PTA) or palladium nanoparticles (Pd-NP) can be immobilized easily. Analysis confirmed that the amine functionalized polymer was performed through quaternization of one amine belonged diamine with polymer-CH2Cl function group and the other free amine acts as active sites to immobilize PTA or Pd-NP through ionic bonding interaction. Through tuning the initial polymer/PTA molar ratios and using different amine chain length as soft linkers, the prepared hybrid catalysts possess controllable structural of hetro-homogeneous nature, which increases the activity, durability and recyclability of catalysts.
PTA-C2H2N-PVBC(CAT-2A-C) can catalyze the glycerol acetylation with very good efficiency while completely avoiding the formation of by-products because of the polymer act as heterogeneous support and PTA attached to diamine act as homogenous catalyst.
The efficiency of the acetylation reaction is significantly influenced by the strength of the acidic sites in the H2N-PVBC material. The obtained catalyst exhibited high activity for glycerol acetylation under mild conditions (T=100°C; Gly:AA=8 and time=3h) and the catalyst also showed high selectivity toward TAG (73.0%) than previously described reports. Furthermore, the catalyst is simply recoverable and can be reused 6th times with no leaching or deactivation due to the ionic bonding interaction of PTA with the amine groups of H2N-PVBC. Consequently, PTA-H2N- PVBC as a heterogeneous homogeneous catalyst has great interest for further industrial applications.
Compared with well known catalyst, Amberlyst-46, the hybrid catalysts (CAT-2A-C, CAT-8A-C and CAT-12A-C) exhibited obviously enhanced hetero-homogeneous acid catalytic activity towards the synthesis of methyl oleate and ethyl oleate from a biomass-derived platform molecule, oleic acid, under atmospheric pressure, refluxing conditions. The conversion reached 99.9% for methyl oleate at the reaction conditions of methanol/acid mole ratio of 6:1, catalyst weight of 4% and 2 h, while ethyl oleate yield reached 98.2% at same condition expect time took 4h.
This excellent acid catalytic activity originates from the combination of strong Bronsted acidity as well as enhanced surface hydrophobicity of the hybrid catalysts. Moreover, CAT-8C and CAT-12C exhibited much higher catalytic activity with respect to the long carbon chain length of 1,8-diaminooctane and 1,12-dodecanediamine, attributed to the high dispersibility and hence decreased mass transfer limitations of the reactants and products. Additionally, the hybrid catalyst can be reused at least seven times with the activity loss lower than 2%. This catalytic stability is due to the strong ionic bonding interaction between the Keggin units and the NH2-polymeric support as well as its hydrophobic surface.
In addition to PTA - based catalysts, palladium nanoparticles can be immobilized on the surface of H2N-PVBC polymer support through chemisorptions bond between palladium and different terminated amino-groups of the polymer (Pd-C12H2N-PVBC). the Catalytic performance of supported palladium has been conducted on reduction of p-nitrophenol (PNP) to p-aminophenol (PAP), and was found that catalytic performance depend strongly on the percent weight of palladium loaded on the polymer support in order of 17.1> 8.9 >5.7 wt-% and reduction was performed faster and in very short time compared with other available catalysts. The catalyst was capable of withstanding six times of catalytic process at room temperature without noticeable deactivation (leaching) due to strong bond between palladium and different terminated amine in addition to structure nature of polymer support which act as strong stabilizer to palladium nanoparticles.