文献类型：期刊文献

英文题名：Synthesis of SalenCo(III)CN Catalyst for Copolymerization and Terpolymerization of Epoxides and Carbon Dioxide

作者：Li, Jia-jia[1];Zhou, Yu-jie[1];Cheng, Rui-hua[1];Liu, Bo-ping[1]

机构：[1]East China Univ Sci & Technol, State Key Lab Chem Engn, Shanghai 200237, Peoples R China

年份：2017

期号：12

起止页码：1915

外文期刊名：ACTA POLYMERICA SINICA

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000419398800006)】；

语种：英文

外文关键词：Carbon dioxide; Polycarbonate; SalenCo((III))CN; Polymerization temperature; Molecular weight

摘要：A new type of the SalenCo((III)) with CN as the co-ligand is developed to catalyze the copolymerization of CO2 with propylene oxide (PO) to afford poly(propylene carbonate) (PPC). The co-ligand (X) is the initiating group during the reaction and becomes the site at which the growing polymer chain is proposed to propagate. The copolymerization rate, selectivity of the polymer to the cyclic carbonate, stereoselectivity, and regioselectivity of the polycarbonate exhibit a pronounced dependence on the nature of the axial ligand. Compared with the SalenCo((III))C1 and SalenCo((III))Br catalysts, the PPC obtained by SalenCo((III))CN catalyst at 25 degrees C presented 98% head-to-tail (HT) connectivity, and without head-to-head linkage. Further increasing the reaction temperature from 25 degrees C to 75 degrees C, the polymerization activity over SalenCoG((III))CN catalysts increased, and the product still maintained a high selectivity for carbonate linkages. The PPC achieved using the SalenCoG((III))CN/PPNC1 (PPNC1 = bis(triphenylphosphino)iminium chloride) catalyst systems at 50 degrees C within 2 h with TOF = 379 mol PO.mol(-1) Co.h(-1) was highly regioregular (HT up to 95%) and had carbonate linkages of up to 99% with a narrow molecular weight distribution (MWD). The SalenCo((III))CN catalyst showed good stability and polymer chain control ability even at 75 degrees C. This novel catalyst efficiently terpolymerized CO2 , PO, and two other kinds of epoxide monomers. When the quantity of the third epoxide was added gradually, the MWD of the generated polymers was broader, indicating the epoxide was incorporated into the PPC chain successfully. The third epoxide monomer not only acted as an interlinkage in the terpolymerization of CO2 and PO, which increased the MW of the resultant terpolymer to a value that increased the glass transition temperature (T-g), but also strongly influenced the productivity of PPC and the selectivity. Introducing the dicyclopentadiene dioxide (EP1) could greatly increase the activity of the catalyst system to TOF = 624 h(-1), with a slight effect on T-g. For the case of 1,3,5-triglycidyl isocyanurate (EP2), it increased MW of the resultant copolymer and the T-g up to 45 degrees C.