碱金属配合物的合成、表征及催化丙交酯开环聚合研究
发布时间：2018-08-11 08:25
【摘要】：脂肪族聚酯以其良好的生物相容性、生物可降解性和渗透性在各领域有着重要的应用,如包装、生物材料、药物载体、医疗设备等。合成脂肪族聚酯最有效的方法是金属配合物催化的开环聚合,该方法合成的聚合物分子量可控,分子量分布窄。其中,外消旋丙交酯聚合物作为一类重要的脂肪族聚酯,其物理化学性能与自身的立体结构有很大的关系,合成具有理想立体构型的聚丙交酯成为研究的焦点。近年来,碱金属催化剂引起了广泛的兴趣,其中类似夹心结构的碱金属配合物表现出良好的催化效果。本文合成和表征了多种碱金属配合物,研究它们对rac-LA开环聚合的催化性能,主要内容如下:第一章介绍了各种金属体系催化环酯开环聚合的研究进展,其中详细介绍了碱金属催化体系的发展过程和现状。第二章介绍了以冠醚为辅助配体,手性及非手性单酚负离子稳定的钠和钾配合物的合成、表征及催化rac-LA开环聚合作用。在BnOH存在下,配合物能有效催化rac-LA开环聚合,聚合物分子量可控,分子量分布较窄,同时有较高的选择性。改变单酚位阻的大小,对催化剂的性能影响较大;而当利用手性及非手性的单酚作为配体时,两者具有相同的立体选择性。第三章介绍了以冠醚为辅助配体,8-羟基喹啉衍生物稳定的钾配合物的合成、表征及催化rac-LA开环聚合作用。配体上的取代基对催化剂的活性影响较大,带强吸电子基团的配体会降低催化剂活性,甚至使催化剂失活。钾配合物3.1在催化rac-LA开环聚合中表现出良好的性能,常温下聚合物的Pm值达到0.72,而在0℃时Pm值达到0.75。第四章介绍了以冠醚为辅助配体,水杨醛亚胺稳定的钠和钾配合物的合成、表征及催化rac-LA开环聚合作用。水杨醛亚胺配体并没有采用双齿配位的形式与碱金属络合,而是采用单酚氧配位的形式。配合物在常温下能高效催化rac-LA开环聚合,其中钾配合物4.4的催化选择性最高,在0℃时聚合物的Pm值达到0.75.第五章介绍了以手性冠醚为辅助配体,大位阻单酚负离子稳定的钠和钾配合物的合成、表征及催化rac-LA开环聚合作用。在BnOH存在下,配合物能高效催化rac-LA开环聚合,聚合物的分子量可控,分子量分布窄。但与传统冠醚螯合的碱金属配合物比较时,其催化反应的选择性并没有提高。另外,还探究了不同的共引发剂对rac-LA开环聚合的影响。
[Abstract]:Aliphatic polyester has important applications in many fields for its good biocompatibility biodegradability and permeability such as packaging biomaterials drug carriers medical equipment and so on. The most effective method for the synthesis of aliphatic polyester is the ring-opening polymerization catalyzed by metal complexes. The molecular weight of the polymer synthesized by this method is controllable and the molecular weight distribution is narrow. As a kind of important aliphatic polyester, the physical and chemical properties of racemic lactide polymer are closely related to its stereoscopic structure. The synthesis of poly (lactide) with ideal stereotype has become the focus of research. In recent years, alkali metal catalysts have attracted wide interest, among them, alkali metal complexes with similar sandwich structure show good catalytic effect. In this paper, a variety of alkali metal complexes have been synthesized and characterized, and their catalytic properties for rac-LA ring-opening polymerization have been studied. The main contents are as follows: in Chapter 1, the research progress of cycloester ring-opening polymerization catalyzed by various metal systems is introduced. The development process and present situation of alkali metal catalytic system are introduced in detail. In chapter 2, the synthesis, characterization and catalytic ring-opening polymerization of rac-LA with chiral and non-chiral monophenol anion stabilized sodium and potassium complexes with crown ether as auxiliary ligands were introduced. In the presence of BnOH, the complexes can effectively catalyze the ring-opening polymerization of rac-LA, the molecular weight of the polymer is controllable, the molecular weight distribution is narrow and the selectivity is high. When the chiral and non-chiral monophenols were used as ligands, they had the same stereoselectivity. In chapter 3, the synthesis, characterization and rac-LA ring-opening polymerization of stable potassium complexes with crown ethers as auxiliary ligands were introduced. The activity of the catalyst was greatly affected by the substituents on the ligands. The combination of the strong electron-absorbing groups decreased the activity of the catalysts and even deactivated the catalysts. Potassium complex 3.1 shows good performance in the ring-opening polymerization of rac-LA. The pm value of the polymer reaches 0.72 at room temperature and 0.75 at 0 鈩，
本文编号：2176439
[Abstract]:Aliphatic polyester has important applications in many fields for its good biocompatibility biodegradability and permeability such as packaging biomaterials drug carriers medical equipment and so on. The most effective method for the synthesis of aliphatic polyester is the ring-opening polymerization catalyzed by metal complexes. The molecular weight of the polymer synthesized by this method is controllable and the molecular weight distribution is narrow. As a kind of important aliphatic polyester, the physical and chemical properties of racemic lactide polymer are closely related to its stereoscopic structure. The synthesis of poly (lactide) with ideal stereotype has become the focus of research. In recent years, alkali metal catalysts have attracted wide interest, among them, alkali metal complexes with similar sandwich structure show good catalytic effect. In this paper, a variety of alkali metal complexes have been synthesized and characterized, and their catalytic properties for rac-LA ring-opening polymerization have been studied. The main contents are as follows: in Chapter 1, the research progress of cycloester ring-opening polymerization catalyzed by various metal systems is introduced. The development process and present situation of alkali metal catalytic system are introduced in detail. In chapter 2, the synthesis, characterization and catalytic ring-opening polymerization of rac-LA with chiral and non-chiral monophenol anion stabilized sodium and potassium complexes with crown ether as auxiliary ligands were introduced. In the presence of BnOH, the complexes can effectively catalyze the ring-opening polymerization of rac-LA, the molecular weight of the polymer is controllable, the molecular weight distribution is narrow and the selectivity is high. When the chiral and non-chiral monophenols were used as ligands, they had the same stereoselectivity. In chapter 3, the synthesis, characterization and rac-LA ring-opening polymerization of stable potassium complexes with crown ethers as auxiliary ligands were introduced. The activity of the catalyst was greatly affected by the substituents on the ligands. The combination of the strong electron-absorbing groups decreased the activity of the catalysts and even deactivated the catalysts. Potassium complex 3.1 shows good performance in the ring-opening polymerization of rac-LA. The pm value of the polymer reaches 0.72 at room temperature and 0.75 at 0 鈩，
本文编号：2176439
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