Two kinids of chitosan derivatives

chitosan condensed with salilylaldehyde and crosslinked chitosan condensed with salilylaldehyde

supported palladium complexes(S-CTS-Pd and CL-S-CTS—Pd)were synthesized and characterized by XPS

TG

DTA etc．TG analysis showed that both S-CTS-Pd and CL-S—CTS-Pd were stable up to 230℃．The complexes were efficient catalysts for Heck arylations of iodoarenes with acrylic acid or styrene under atmospheric condition

and the trails-cinnamic acid or trails—stilbene was obtained in high yield(≥90％)．Neither electron-donating groups nor electron—withdrawing groups on iodoarenes had much effect on the yield of products．The catalytic activities of S-CTS-Pd and CL-S-CTS-Pd decreased slowly while the temperature decreased from 100℃ to 80℃．With reducing reaction temperature continuously

the catalytic activity of S-CTS-Pd reduced remarkably

however．the catalytic activity of CL-S—CTS—Pd remained at a very high level．The influence of amount of catalyst on catalytic performance of S-CTS-Pd and CL-S-CTS-Pd showed that CL-S-CTS-Pd had better performance than S-CTS-Pd．The recyclability of CL-S-CTS-Pd showed that the yield of cinnamic acid was 75．3％ for Heck reaction of acrylic acid with iodobenzene even though the supported catalyst was used 10 times．