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Cost-Effective Synthesis of High Molecular Weight Biobased Polycarbonate via Melt Polymerization of Isosorbide and Dimethyl Carbonate
ACS Sustainable Chemistry & Engineering ( IF 7.1 ) Pub Date : 2020-06-22 , DOI: 10.1021/acssuschemeng.0c00430
Zifeng Yang 1, 2 , Lei Liu 1 , Hongzhe An 1 , Chenhao Li 1 , Zhencai Zhang 1 , Wenjuan Fang 1 , Fei Xu 1 , Suojiang Zhang 1, 2
Affiliation  

Green synthesis of poly(isosorbide carbonate) (PIC) with remarkable properties is a huge challenge in industrial applications due to low molecular weight and harsh reaction conditions. We reported a novel pathway to synthesize high molecular weight PIC through melt polymerization of isosorbide (ISB) and dimethyl carbonate (DMC), which are derived from the biomass and CO2, respectively. The effects of metal ion-containing compound catalyst on chemical structures, terminal groups, and molecular weight of PIC in the process of melt polycondensation were studied. Compared with the best reported catalyst lithium acetylacetonate, the weight-average molecular weight (Mw) of PIC was increased by using our preferred catalyst sodium tert-butoxide from 46 500 to 55 100 with the ISB conversion up to 99.0%, and the reaction time was decreased from 12 h to only 2.5 h, as far as we know, which is the highest Mw value and the most efficient catalyst achieved by one-step method. According to the results of the experiment and simulation, we found that high catalytic performance was ascribed to the weak interaction energy of anion–cation of catalyst and the strong proton acceptance ability of the anion of the catalyst. Meanwhile, increasing the interaction energy of anion–cation of the catalyst could inhibit the occurrence of the methylation side reaction and interestingly the activated endohydroxyl groups of ISB were found to be more easily methylated. Finally, based on the captured and detected intermediates of the two-stages of the reaction, a possible mechanim for the synergetic effects of cation–anion through hydrogen bond formation was proposed.

中文翻译:

异山梨醇和碳酸二甲酯的熔融聚合经济高效地合成高分子量生物基聚碳酸酯

由于分子量低和反应条件苛刻,具有卓越性能的绿色聚碳酸异山梨酯(PIC)的绿色合成在工业应用中是一项巨大的挑战。我们报道了通过异山梨醇(ISB)和碳酸二甲酯(DMC)的熔融聚合合成高分子量PIC的新途径,这分别来自生物质和CO 2。研究了含金属离子的复合催化剂对熔融缩聚过程中PIC的化学结构,端基和分子量的影响。与报告最多的催化剂乙酰丙酮锂相比,重均分子量(M w通过使用我们首选的叔丁醇钠催化剂将PIC值从46500增加到55100,ISB转化率高达99.0%,并且据我们所知,反应时间从12小时减少到仅2.5小时,是最高的M w价值和最有效的催化剂,一步法即可实现。根据实验和模拟的结果,我们发现高的催化性能归因于催化剂阴离子与阳离子的相互作用能弱,以及催化剂阴离子的强质子接受能力。同时,增加催化剂阴离子与阳离子的相互作用能可以抑制甲基化副反应的发生,有趣的是,ISB的活化内羟基被更容易甲基化。最后,根据捕获和检测到的两阶段反应的中间体,提出了通过氢键形成对阳离子-阴离子协同作用的一种可能机理。
更新日期:2020-07-13
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