6919-32-0Relevant academic research and scientific papers
Pinwheel-Shaped Tetranuclear Organoboron Catalysts for Perfectly Alternating Copolymerization of CO2and Epichlorohydrin
Yang, Guan-Wen,Xu, Cheng-Kai,Xie, Rui,Zhang, Yao-Yao,Zhu, Xiao-Feng,Wu, Guang-Peng
supporting information, p. 3455 - 3465 (2021/03/08)
The copolymerization of carbon dioxide (CO2) and epoxides to produce aliphatic polycarbonates is a burgeoning technology for the large-scale utilization of CO2 and degradable polymeric materials. Even with the wealth of advancements achieved over the past 50 years on this green technology, many challenges remain, including the use of metal-containing catalysts for polymerization, the removal of the chromatic metal residue after polymerization, and the limited practicable epoxides, especially for those containing electron-withdrawing groups. Herein, we provide kinds of pinwheel-shaped tetranuclear organoboron catalysts for epichlorohydrin/CO2 copolymerization with >99% polymer selectivity and quantitative CO2 uptake (>99% carbonate linkages) under mild conditions (25-40 °C, 25 bar of CO2). The produced poly(chloropropylene carbonate) has the highest molecular weight of 36.5 kg/mol and glass transition temperature of 45.4 °C reported to date. The energy difference (ΔEa = 60.7 kJ/mol) between the cyclic carbonate and polycarbonate sheds light on the robust performance of our metal-free catalyst. Control experiments and density functional theory (DFT) calculations revealed a cyclically sequential copolymerization mechanism. The metal-free feature, high catalytic performance under mild conditions, and no trouble with chromaticity for the produced polymers imply that our catalysts are practical candidates to advance the CO2-based polycarbonates.
Novel 3-sulfinatomethyl-or 3-sulfonatomethyl-4-sulfomethyl pyrrolidinium betaines and their salts as well as process for making the same
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, (2008/06/13)
Novel 3-sulfinatomethyl or 3-sulfonatomethyl-4-sulfomethyl-pyrrolidinium betaines are disclosed which have the formula STR1 These novel compounds are obtained by reacting diallyl-triallyl ammonium salts or their methallyl derivatives with hydrogen sulfite in the presence of peroxo disulfates alone or in a mixture with other oxidation agents with a pH-value-range from 1.5 to 6.0 in a watery solution, whereby in light of the selection of the amount of hydrogen sulfite in combination with the amount peroxo disulfate different SO 2 - --or SO 3 - substituted sulfomethyl-pyrralidinium betaines are generated.The novel compounds are effective as specific tensides in a wide pH-range and can be extensively used as intermediary products.
