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为解决聚合物中有毒金属残留问题,选择绿色环保的金属铝作为催化剂活性中心,并通过将助催化剂季铵盐接在卟啉配体上的方法,合成了新型双官能化卟啉铝配合物,通过1H-NMR、13C-NMR、MALDI-TOF等方法对其进行了表征和确认.该催化体系可在不加助催化剂的条件下高效催化CO2/环氧丙烷(PO)共聚合,其活性显著高于传统的卟啉铝配合物/季铵盐双组份催化体系.使用配合物1b详细考察了温度、压力等因素对聚合反应的影响,在90℃,3.0 MPa的反应条件下,反应5 h后TOF(单位时间内每摩尔催化剂转化的单体数)可达1152 h-1,所得聚合物碳酸酯含量98%,数均分子量Mn=42×103,但聚合物选择性较低(68%).配合物1b同样可以高效的催化CO2/环氧环己烷(CHO)共聚,在相同的反应条件下,TOF可达621 h-1,聚合体系中无环状副产物生成,所得聚合物碳酸酯含量81%,数均分子量Mn=8.0×103.另外,通过改变配合物中的季铵盐阴离子和轴向配体,考察了不同引发基团对催化剂活性、聚合物选择性的影响.
In order to solve the problem of residual toxic metals in polymers, a new type of bifunctional porphyrin aluminum complex was synthesized by selecting the green metal aluminum as the active site of the catalyst and attaching the cocatalyst quaternary ammonium salt to the porphyrin ligand , Which was characterized by 1H-NMR, 13C-NMR and MALDI-TOF.The catalytic system can efficiently catalyze the copolymerization of CO2 / propylene oxide (PO) with no cocatalyst, and its activity Was significantly higher than the traditional two-component porphyrin complex / quaternary ammonium catalyst system.Using the complex 1b, the effect of temperature and pressure on the polymerization was investigated in detail. Under the reaction conditions of 90 ℃ and 3.0 MPa, After 5 h, the TOF (number of converted monomers per mole of catalyst per unit time) was 1152 h-1. The resulting polymer had a carbonate content of 98% and a number average molecular weight of Mn = 42x103, but with a lower polymer selectivity 68%). The complex 1b also efficiently catalyzed the copolymerization of CO2 / cyclohexene oxide (CHO). Under the same reaction conditions, the TOF was up to 621 h-1. No cyclic by-products were formed in the polymerization system. The polymer carbonate content was 81% and the number average molecular weight Mn was 8.0 × 103. In addition, by changing the content of the complex Quaternary ammonium salts and anionic axial ligands, investigated the effect of different radical initiator group on the catalyst activity, selectivity of the polymer.