The Preparation Of Highly Active Aminated Modified Resin Supported Palladium Complexes And Their Catalytic Activity For Heck Reaction

Palladium-catalyzed Heck reactions of aryl halides with alkeneshave become one of the most powerful tools in orgnic synthesis for theconstruction of carbon-carbon bond. Studying the correspondingliteratures, found that aryl iodides and activated alkenes are typicallyemployed as the coupling reactants of a great number of reactions, and avariety of the efficient palladium catalyst systems have been developed.Aryl bromides and aryl chlorides are cheaper and more easily availablethan aryl iodides. Resently, researchers make great efforts to establish theefficient catalyst systems for making Heck reactions of aryl bromides andaryl chlorides extensively, but among the reported literatures, the yeildsof coupling reactions are not satisfied, or conditions of reacitons arerigorous(higher temperature, inert atmosphere, and so on), the catalystsystems reported which show high catalytic activity and excellentreusability in Heck reactions of aryl bromides are still few. The aim of ourresearch work is to develop a series of efficient catalysts for the Heckreaction of aryl bromides and aryl chlorides, and the catalysts havesuperexcellent reusability.In the thesis, we chose aminated resin as support. In Heck reactionsof aryl bromides and aryl chlorides, catalytic activity of series ofaminating-reagent-modified-resin supported palladium has beenresearched, and the reusability in the Heck coupling of aryl bromids catalyzed by aminated resin supported palladium has been investigated.And the possible mechanism of Heck reaction has been discussed.Firstly, amino-guanidine-resin supported Pd(0) was prepared by thereaction of amino- guanidine modified chloromethyl polystyrene resinwith PdCl₂, followed by reduction. The catalyst was characterized byFT-IR, XRD, BET, TG-DTA. The catalytic performance for the Heckreactions of various substituted aryl halides with acrylic acid or styrenewas researched. Experiments indicated that the catalyst hadsuperexcellent activity and outstanding recycling: Aryl bromides withelectron-withdrawing were converted completely within very short time(140℃,20 min); at 90℃in the reaction of iodo-benzene with acrylic acid,the catalyst could kept high activity at 22th run, at 140℃in the reaction ofacrylic acid and styrene with 4-Bromobenzaldehyde,amino-guanidine-resin supported Pd(0) was able to re-use at least 23 and18 times without significant loss of activity, and the yield exceeded 90ï¼….The mechanism of Heck reaction indicated that the active species wassoluble active Pd species, and the dissolving of palladium in the reactionmixture was due to the oxidative action ofhalides with palladium on thesurface of catalyst, the dissolved active palladium species redepositedonto the surface of catalyst during reaction.Secondly, the catalytic activity of series of amine reagants-guanidineand triazole modified resin supported palladium is investigated. The influence of tempareture, solvents, and catalyst prepared in differentsolvents of PdCl₂ on catalysis and reusability of GDR.Pd(O) catalyst wasstudied, too. By studying it, the better reaction condition was achieved.The relationship between catalitic activity, reusability and active Pdspecies, redeposition was researched.