SalenAl(O^iPr)催化CO2与氧化环己烯共聚及影响因素研究  

STUDIES OF THE COPOLYMERIZATION OF CARBON DIOXIDE AND CYCLOHEXENE OXIDE WITH SALENAl(O^iPr) CATALYST AND EFFECTS OF REACTION CONDITIONS

作　　者：罗建新[1] 崔奇[1] 张敏[1] 刘保华[1] 陈立班[1] 

机构地区：[1]中国科学院广州化学研究所

出　　处：《高分子学报》2008年第5期454-459,共6页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20274053)资助项目;广州市科技攻关项目(项目号2007z3-D0261)

摘　　要：以SalenAl(OiPr)为催化剂,分别加入各种路易斯碱作为共催化剂催化二氧化碳与氧化环己烯共聚,发现共聚催化效率与共催化剂的供电子能力有关.分别研究催化剂浓度、共催化剂的用量、反应时间、反应温度、CO2压力等各种因素对该共聚反应的影响,发现SalenAl(OiPr)浓度为2 g/L时,以等摩尔量的二甲氨基吡啶(DMAP)作为共催化剂,在4 MPa的CO2和80℃下反应32 h,可得到碳酸酯键含量>99%的共聚产物,其催化效率高达495 g/g,13C-NMR检测表明共聚物为无规立构聚合物,GPC测得分子量Mn为55900,分子量分布比较窄(PDI=1.32).DSC得到共聚物的玻璃化转变温度为136℃,热重分析(TGA)可以看出共聚物在350℃可完全分解,具有优良的热分解性.SalenAl （ O^i Pr） complex, prepared by reaction of SalenH2 （ N, N＇-bis （ salicylidene ）-1,2-phenylene- diamine） and isopropoxide aluminum, has been shown to be an effective catalyst for the coupling of carbon dioxide and cyclohexene oxide to afford poly（cyclohexenylene carbonate） （PCHC） with small quantities of byproduct. The addition of various cocatalysts, including 4-dimethyl（amino） pyridine （DMAP）, N-methyl imidazole （ N- MeIm）, 1,8-diazabicyclo（5.4.0） undec-7-ene （DBU） and tetra- n-butylammonium chloride （ Bu4 NCl） can greatly enhance the catalytic efficiency, and more donating DMAP can offer the best copolymerization result. The relative DMAP loading also plays an important role in polymer formation. Experiments indicated that 1 equiv of DMAP was the optimum cocatalyst loading. At higher cocatalyst loading, there is a little increase in polyether linkages as well as a dramatic decrease in the molecular weight of the coplymer. Effects of reaction condition such as catalyst concentration, reaction time, temperature, CO2 pressure on copoymerization were probed in detail. Through varying catalyst concentration, it was found that both lower and higher catalyst concentration led to lower catalytic efficiency and lower Mw, and maximum catalytic efficiency was observed in the presence of catalyst concentration around 2 g/L. The catalyst concentration seemed not to influence the carbonate content in the copolymer significantly. Almost in all cases highly alternative copolymers were obtained.As far as reaction time is concerned, the catalytic efficiency and molecular weight are enhanced with increasing time at the beginning, it reaches a maximum around 52 h, and then drops slowly. Carbonate content as low as 96.5 % was observed at the very beginning, afterward the copolymerization quickly tended to proceed alternatively. Both the catalytic efficiency in copolymerization and molecular weight of PCHC raised with increasing reaction temperature from 40 ℃ to 80℃. At tem

关 键 词：二氧化碳 氧化环己烯 共聚 SalenAl(O'Pr) 热分解 

分 类 号：O631.3[理学—高分子化学]