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Effect of cross-linker on morphology, catalytic activity, and recyclability of immobilized palladium chloride

Authors

  • Yong-Guang Jia,

    1. State Key Laboratory of Elemento-Organic Chemistry, The College of Chemistry, Nankai University, Tianjin 300071, China
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  • Jian Jiang,

    1. State Key Laboratory of Elemento-Organic Chemistry, The College of Chemistry, Nankai University, Tianjin 300071, China
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  • Ling-Yan Liu,

    Corresponding author
    1. State Key Laboratory of Elemento-Organic Chemistry, The College of Chemistry, Nankai University, Tianjin 300071, China
    • State Key Laboratory of Elemento-Organic Chemistry, The College of Chemistry, Nankai University, Tianjin 300071, China
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  • Wei-Xing Chang,

    1. State Key Laboratory of Elemento-Organic Chemistry, The College of Chemistry, Nankai University, Tianjin 300071, China
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  • Jing Li

    Corresponding author
    1. State Key Laboratory of Elemento-Organic Chemistry, The College of Chemistry, Nankai University, Tianjin 300071, China
    • State Key Laboratory of Elemento-Organic Chemistry, The College of Chemistry, Nankai University, Tianjin 300071, China
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Abstract

Two kinds of immobilized palladium (Pd) catalysts were prepared by reversible addition fragmentation chain transfer polymerization of pyridine-containing monomer followed by immobilizing palladium chloride (PdCl2) on block copolymers. Namely, one of them includes the cross-linking structure of maleic anhydride with 1,6-diaminohexane (cross-linker), polystyrene-block-poly(4-(4-vinylbenzyloxy)butylpicolinate-alt-maleic anhydride)-Pd (PS-b-P(VBP-alt-MAn)-Pd), and the other is its non-cross-linking counterpart, polystyrene-block-poly(4-(4-vinylbenzyloxy) butylpicolinate)-Pd (PS-b-PVBP-Pd). From transmission electron microscopy images, it could be observed that they both assembled into micelles in the selective solvents. The Pd of PS-b-P(VBP-alt-MAn)-Pd located in the core of micelles, whereas the Pd of PS-b-PVBP-Pd was on the shell of the micelles. The PS-b-P(VBP-alt-MAn)-Pd can be continuously used for five times without any appreciable loss of activity in the aqueous Suzuki-coupling reaction. However, the catalytic activities of the PS-b-PVBP-Pd decreased sharply with the increase in the recycle times. Thus, this promising cross-linking strategy not only greatly restrained the loss of Pd in the catalytic cycles, but also effectively maintained the immobilized Pd catalyst's high activity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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