Bukowski Wiktor, Bukowska Agnieszka, Sobota Aleksandra, Pytel Maciej, Bester Karol
Faculty of Chemistry, Rzeszow University of Technology, Powstańców Warszawy 6, 35-959 Rzeszow, Poland.
Doctoral School of Engineering and Technical Sciences at the Rzeszow University of Technology; 35-959 Rzeszów, Poland.
Polymers (Basel). 2021 May 28;13(11):1785. doi: 10.3390/polym13111785.
The effect of ligand structure on the catalytic activity of amine-bis(phenolate) chromium(III) complexes in the ring-opening copolymerization of phthalic anhydride and a series epoxides was studied. Eight complexes differing in the donor-pendant group (R) and substituents (R) in phenolate units were examined as catalysts of the model reaction between phthalic anhydride and cyclohexane oxide in toluene. They were used individually or as a part of the binary catalytic systems with nucleophilic co-catalysts. The co-catalyst was selected from the following organic bases: PPh, DMAP, 1-butylimidazole, or DBU. The binary catalytic systems turned out to be more active than the complexes used individually, and DMAP proved to be the best choice as a co-catalyst. When the molar ratio of [PA]:[epoxide]:[Cr]:[DMAP] = 250:250:1:1 was applied, the most active complex (R-X = CHNMe, R = F) allowed to copolymerize phthalic anhydride with differently substituted epoxides (cyclohexene oxide, 4-vinylcyclohexene oxide, styrene oxide, phenyl glycidyl ether, propylene oxide, butylene oxide, and epichlorohydrin) within 240 min at 110 °C. The resulting polyesters were characterized by up to 20.6 kg mol and narrow dispersity, and they did not contain polyether units.
研究了配体结构对胺 - 双（酚盐）铬（III）配合物在邻苯二甲酸酐与一系列环氧化物的开环共聚反应中催化活性的影响。考察了八种在酚盐单元中供体侧基（R）和取代基（R）不同的配合物，作为邻苯二甲酸酐与环氧环己烷在甲苯中模型反应的催化剂。它们单独使用或作为与亲核共催化剂组成的二元催化体系的一部分。共催化剂选自以下有机碱：三苯基膦（PPh）、4 - 二甲氨基吡啶（DMAP）、1 - 丁基咪唑或1,8 - 二氮杂双环[5.4.0]十一碳 - 7 - 烯（DBU）。结果表明，二元催化体系比单独使用的配合物更具活性，并且DMAP被证明是作为共催化剂的最佳选择。当应用[邻苯二甲酸酐]：[环氧化物]：[铬]：[DMAP] = 250：250：1：1的摩尔比时，活性最高的配合物（R - X = CHNMe，R = F）能使邻苯二甲酸酐与不同取代的环氧化物（环氧环己烷、4 - 乙烯基环氧环己烷、氧化苯乙烯、苯基缩水甘油醚、环氧丙烷、环氧丁烷和环氧氯丙烷）在110℃下240分钟内发生共聚反应。所得聚酯的特性粘度高达20.6 kg/mol且分散度窄，并且它们不含聚醚单元。
