Poly(vinylidene dichloride)-diethylene Triamine Supported Palladium as a New Re-cyclable Catalyst for Heck Reaction

Poly(vinylidene dichloride)-diethylene triamine supported palladium complex(PVDC-DTA-Pd) was prepared from poly(vinylidene dichloride) by a simplemethod. In contrast with other polymer-supported catalysts, the greatestadvantage of the catalyst system was that the cost of the catalyst was remarkably lowdue to the easily obtained materials and the simple synthetic route. Heck reactions ofaryl iodides with acrylic acid catalyzed by PVDC-DTA-Pd could be performedefficiently in water. Yield of cinnamic acid was 99.6% as the coupling of iodobenzenewith acrylic acid was carried out in water at 90°C for 3 h in the air. Both electron-richand electron-deficient aryl iodides reacted with the alkenes to give the correspondingtrans-products. When styrene was adopted as alkene, high yields were obtained inDMF rather than in water because the hydrophilicity of styrene was poor. Highactivities for aryl bromides and activated aryl chlorides were also found when thereactions were carried out in tetrabutylammonium bromide to afford the coupledproducts in moderate to good yields. However, high temperature (120°C) and inertatmosphere were required. The catalyst can be recovered easily by filtration andre-used for Heck reaction. Yield of the cinnamic acid was up to 78.5% at the cycle offive, which indicated the high stability and good re-usability of PVDC-DTA-Pd.