PVC-二亚乙基三胺(DETA)-Pd对Heck反应的催化性能研究

CATALYTIC PERFORMANCE OF PVC-DIETHYLENETRIAMINE(DTEA)-Pd FOR HECK REACTIONS

以聚氯乙烯为原料,用较简单的方法得到了聚氯乙烯二亚乙基三胺负载钯配合物(PVC-DETA-Pd).PVC-DETA-Pd具有较高的热稳定性,可以满足Heck反应所需要的高温条件.在110℃、氮气氛围,四丁基溴化铵(TBAB)做溶剂的条件下,PVC-DETA-Pd催化溴苯与苯乙烯的反应产率可以达到99%.PVC-DETA-Pd在多种缚酸剂的存在下均可有效地催化芳基溴的Heck反应,但在三丁胺中具有最好的效果.在适当的反应条件下,以PVC-DETA-Pd为催化剂,各种带取代基芳基溴、芳基氯均可以有效地与乙烯基化合物反应,反应产率>70%.PVC-DETA-Pd还具有较好的重复使用性能.

Polyvinyl chloride-diethylenetriamine supported palladium complex（PVC-DETA-Pd） was synthesized from polyvinyl chloride via a simple method,and the production cost of the complex was low.PVC-DETA-Pd has good thermal stability,so it can satisfy the high temperature condition of the Heck reaction.XPS analysis shows that two different chemical states of palladium,Pd^0 and Pd^2＋,are existed in PVC-DETA-Pd.The molar ratio of Pd^0 to Pd^2＋ is 1∶1.44.PVC-DETA-Pd is an efficient catalyst for Heck arylations of aryl bromides（or chlorides）,which are cheaper substrates than aryl iodides.The yield of the Heck reaction of bromobeneze and styrene catalyzed by PVC-DETA-Pd was up to 99% in nitrogen atmosphere at 110℃ and tetrabutylammonium bromide（TBAB） as solvent.The reaction of bromobeneze with styrene was catalyzed efficiently by PVC-DETA-Pd in presence of several kinds of acid-binding agents such as Et3N,Bu3N,Na2CO3 and NaAc.The best result was obtained when tributylamine was chosen as the acid-binding agent.The Heck reactions of substituted aryl bromides with vinyl compounds can also be catalyzed efficiently on proper conditions,the yields of the products were more than 70%.Chlorobenzene reacts with styrene to give the moderate yield of 78%.By substituting the chlorobenzene with 4-nitro chlorobenzene,the yield of the product was increased to 80%.Furthermore,the good reusability of PVC-DETA-Pd was also found for Heck reaction.The yield of the stilbene was 74% even if PVC-DETA-Pd was reused five cycles for the model reaction of bromobenzene and styrene.