【作者】 王勇；

【导师】 陈昶乐；

【作者基本信息】 中国科学技术大学 ， 高分子化学与物理， 2022， 硕士

【摘要】 聚烯烃在生产生活中应用极为广泛。新的聚烯烃产品的出现离不开烯烃聚合技术的革新。助催化剂作为绝大多数过渡金属催化体系的必要成分,在其中扮演着非常重要的角色。助催化剂不仅可以活化预催化剂使其成为活性物种,同时还可以与路易斯酸添加剂一样利用自身路易斯酸性对催化体系进行调控,从而增强催化体系的性能。新型高效助催化剂的开发,有利于新催化体系的出现并且使得原有催化体系更加高效。本文从常用的三(五氟苯基)硼烷(FAB)入手,合成了一系列的含硼助催化剂,并研究了吡啶-胺基铪被硼助催化剂活化后催化乙烯聚合的行为。同时,利用活化后的铪催化体系进行了乙烯-辛烯的共聚研究。随后,合成了一系列的新型膦磺酸钯催化剂,研究膦磺酸钯在不同的助催化剂作用下的差异。研究结果如下:1.首先,我们进行了含硼助催化剂与吡啶-胺基铪催化的乙烯均聚研究。在80℃的聚合温度下,FAB催化体系和叔丁基氧二(五氟苯基)硼催化体系均可以高活性催化乙烯聚合得到高分子量聚合物,且80℃时叔丁基氧硼体系聚合活性是FAB体系的5倍。即使在140℃,叔丁基氧硼体系仍然具有2.46×106g mol-1 h-1的聚合活性,且聚合物分子量可达7.8×104 g mol-1。2.随后,我们对吡啶-胺基铪催化的乙烯-辛烯共聚进行了研究。80℃聚合温度下,FAB体系的聚合活性相较于乙烯均聚降低了 2倍,而叔丁基氧硼体系仍然可以达到2.49×106g mol-1 h-1的聚合活性,同时具有15.8%的辛烯插入比。随着温度的升高,叔丁基氧硼体系的辛烯插入比得到提高,但是聚合活性和分子量逐渐下降。3.另外,在我们新合成的三种膦磺酸钯催化剂中,含N的五元杂环Pd1展现出对乙烯均聚的高活性,但因位阻小而得到低分子量聚合物,含N的六元杂环Pd2和Pd3因具有大的位阻,得到高分子量聚合物。在向三种钯催化剂中加入不同的助催化剂后发现,三者的聚合活性和分子量都得到了提升。Pd1在高活性下分子量提升5倍,Pd3的分子量得到了 3倍的提升,Pd2更为明显,在活性提升将近1个数量级的同时分子量提升4倍。进一步的研究表明路易斯酸助催化剂的引入与膦磺酸钯上含N杂环发生了相互作用。更多还原

【Abstract】 Polyolefin products are widely used in industry and our lives.The emergence of new polyolefin products depends on the innovation of catalyst technology.Cocatalysts play an important role in transition metal-catalyzed olefin polymerization.The cocatalyst can not only activate the pre-catalyst,but also,like the Lewis acid additive,can control the catalytic system to a certain extent via its own Lewis acidity,thereby improving the catalytic properties.The development of new high-efficiency and low-cost cocatalysts is conducive to the emergence of new catalytic systems and makes the known catalytic systems more efficient.In this work,we synthesized a series of boron cocatalysts.Subsequently,we used these cocatalysts to activate transition metal hafnium catalysts for olefin polymerization.At the same time,we synthesized a series of palladium phosphine sulfonate catalysts,and use Lewis acids to tune these catalysts.The following results were obtained:1.First,we investigated ethylene polymerization catalyzed by boranes activated pyridine-amine hafnium catalysts.At 80℃,both the FAB catalytic system and the oxy-tert-butyl boron catalytic system can obtain high molecular weight polymers at high activity,and the polymerization activity of the oxy-tert-butyl boron system at 80℃ is 5 times of that of the FAB system.Even at 140℃,the oxy-tert-butyl boron system can obtain a polymerization activity of 2.46 ×106 g mol-1 h-1 and a polymer molecular weight of 7.8× 104 g mol-1.2.Subsequently,we investigated the ethylene-octene copolymerization performance of the hafnium catalyst activated by boron cocatalysts.At 80℃,the polymerization activity of the FAB system was 2 times lower than that of ethylene homopolymerization,while the oxy-tert-butyl boron system could still achieve a polymerization activity of 2.49×106 g mol-1 h-1,with 15.8%octylene insertion.With the increase of temperature,although the octene insertion ratio of the oxy-tert-butyl boron system increased,the polymerization activity and molecular weight decreased gradually.3.In addition,in the ethylene polymerization catalyzed by palladium phosphinesulfonate,the N-containing five-membered ring Pd1 exhibits high activity for ethylene polymerization,but the steric hindrance is small,so a low molecular weight polymer was obtained,while the N-containing six-membered ring Pd2 and Pd3 gives high molecular weight polymers.The activity and molecular weight of the three palladium catalysts were improved with the addition of Lewis acid.The molecular weight of Pd1 is increased by 5 times at high activity,the molecular weight of Pd3 is increased by 3 times,and the increase of Pd2 is more obvious,and the molecular weight is increased by 4 times when the activity is increased by nearly an order of magnitude.Further investigation revealed that the introduction of Lewis acid interacted with N on palladium phosphine sulfonate.更多还原