The Selective Synthesis Of δ-lactone And Its Polymerization Based On CO₂

δ-lactone is a very useful compound, which is synthesized through transition metal-catalyzed telomerization of CO2 and 1,3-butadiene. It can be used for hydrogenation, hydroformylation, hydroaminomethylation, hydroamination, alcoholysis, hydrolysis, hydrosilylation, epoxy reaction and addition polymerization reactions. However, the shortcomings of existing synthetic methods which limit its use in laboratory research and industry production is giving a low selectivity to 8-lactone, therefore, selective synthesis ofδ-lactone and expanding its scope of application is of great significance.1. Based on the air-stable triphenylphosphine, a series of P-ligands L1-L13 were synthesized and used for telomerization of CO2 and 1,3-butadiene, where L13 was a unknown compound and its structure was characterized by 1H NMR,13C NMR, IR and HRMS. Among them Pd(acac)2/L2 catalyst system provided the best results for selective synthesis ofδ-lactone. The highest yield of 43% and selectivity of 57% were observed respectively.2. The double bond polymerization ofδ-lactone was subsequently studied. The effects of the reaction time, the reaction temperature and the amount of catalyst on the reaction were investigated. The results show that in the presence of 0.2 mol% Cu(OTf)2 at 150℃for 48 h, the polymer with the larger weight average molecular weight and narrow polydispersity index can be obtained. Meanwhile, a derivative ofδ-lactone 49 was attempted to chain polymerization, and the catalyst and the reaction temperature were investigated. The results show that it is difficult for 49 to lead chain polymerization.