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Effect of cross‐linker on morphology, catalytic activity, and recyclability of immobilized palladium chloride
Author(s) -
Jia YongGuang,
Jiang Jian,
Liu LingYan,
Chang WeiXing,
Li Jing
Publication year - 2012
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.38417
Subject(s) - palladium , catalysis , micelle , polymer chemistry , maleic anhydride , copolymer , polystyrene , chemistry , monomer , polymerization , aqueous solution , materials science , organic chemistry , polymer
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 (PdCl 2 ) 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