【摘要】 以磷钨酸(PW12)为催化剂,催化β-蒎烯阳离子聚合,显示出良好的催化活性。采用1H NMR、XPS、XRD、FTIR、GPC和GC-MS对催化剂及反应产物进行了表征,实验结果表明:磷钨酸在反应前后Keggin结构没有发生变化,在聚合反应中起引发剂和抗衡负离子的双重作用;在-15℃时,该反应以聚合反应为主,异构化反应为次;聚合物的结构表征和异构化产物均支持β-蒎烯阳离子开环聚合机理;采用单因素实验,得出了β-蒎烯阳离子聚合的最佳工艺条件:聚合温度-15℃,PW12用量5%(质量),V溶剂∶V单体=1∶1,反应时间9 h,PW12的焙烧温度200℃,焙烧时间4 h,溶剂为1,2-二氯乙烷。在此条件下聚合,β-蒎烯转化率达97.37%,不溶于乙醇的聚β-蒎烯树脂得率为60.85%,相对数均分子质量约为1170。更多还原

【Abstract】 β-Pinene polymerization is usually initiated with cationic catalysts.Lewis acids such as AlCl3,BF3,TiCl4 are the most effective catalysts and therefore commonly used in the commercial process.But the halides can cause severe problems of environmental hazards and poison hydrogenation catalysts in later hydrogenation process.In addition,dark color of polymer obtained limits its application in many areas in which light color or colorless resins are required.Keggin heteropolyacids(HPAs) are of some advantages such as high catalytic activity,high thermal and oxidative stability,non-corrosion and non-polluting to environment,and have been paid more and more attention in organic synthesis and the petrochemical industry.12-Phosphotungstic acid(PW12) catalyst is explored for β-pinene cationic polymerization in this paper.The catalyst and polymer obtained are characterized by 1H NMR,XPS,XRD,FTIR,GPC and GC-MS,and it is shown that the crystal structure of the heteropolyanion is not destroyed during the reaction.The protons dissociating from the catalyst play an important role in the polymerization.The PW12 is both polymerization initiator and the counter-anion of the growing cation center.The effect of solvent, calcination temperature and time,reaction temperature and time,and the dosage of catalyst on the catalytic performance are studied too.Under optimum reaction conditions,the overall conversion of β-pinene is up to 97.37%,and the polymer yield is 60.85% and its average number molecular weight is about 1170.更多还原