SalenCo^(Ⅲ)CN的合成及其催化二氧化碳和环氧化物共聚研究  

Synthesis of SalenCo^(Ⅲ) CN Catalyst for Copolymerization and Terpolymerization of Epoxides and Carbon Dioxide

作　　者：李佳佳[1] 周宇杰 程瑞华[1] 刘柏平[1] 

机构地区：[1]华东理工大学化学工程联合国家重点实验室,上海200237

出　　处：《高分子学报》2017年第12期1915-1921,共7页Acta Polymerica Sinica

基　　金：上海市浦江人才计划(项目号16PJD016)资助项目

摘　　要：采用具有新型轴向配体的Salen Co(III)CN催化剂在25~100oC的聚合温度下催化二氧化碳和环氧丙烷(PO)共聚制备聚碳酸酯(PPC).CN具有吸电子能力,在50oC下Salen Co(III)CN/PPNCl体系催化二氧化碳和环氧丙烷聚合的活性为TOF=379 h-1,产物的区域选择性>95%,碳酸酯单元含量>99%,且分子量分布极窄.在该催化体系中分别加入二环戊二烯环氧化物(EP1)、1,3,5-三缩水甘油-S-三嗪三酮(EP2)与二氧化碳和环氧丙烷三元调聚合.在相同条件下,EP1使催化活性显著升高至624 h-1,但对产物分子量和玻璃化转变温度(Tg)影响不明显;EP2的加入对活性的影响不明显,但可使聚碳酸酯的分子量增大至Mn=1.97?104,PDI=5.07,产物的Tg升至45oC.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）Cl and SalenCo^（Ⅲ）Br catalysts, the PPC obtained by SalenCo^（Ⅲ）CN catalyst at 25 ℃ presented 98% head-to-tail （HT） connectivity, and without head-to-head linkage. Further increasing the reaction temperature from 25 ℃ to 75 ℃, the polymerization activity over SalenCo（m）CN catalysts increased, and the product still maintained a high selectivity for carbonate linkages. The PPC achieved using the SalenCo（m）CN/PPNC1 （PPNCI = bis（triphenylphosphino）iminium chloride） catalyst systems at 50 ℃ within 2 h with TOF = 379 mol PO＇mol-- Co-h-- was highly regioregular （HT up to 95%） and had carbonate linkages of up to 99% with a narrow molecular weight distribution （MWD）. The SalenCoOH）CN catalyst showed good stability and polymer chain control ability even at 75 ℃. 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 （Tg）, but also strongly influenced the productivity of PPC and the selectivity. Introducing the dicyclopentadiene dioxide （EP 1） could greatly increase

关 键 词：二氧化碳 聚碳酸酯 Salen催化剂 聚合温度 分子量 

分 类 号：O633.14[理学—高分子化学] O643.36[理学—化学]