Research and Development of Environmentally Friendly Precision ControlledPolymerization: Living Pol vmerization in Water

本研究旨在发展环境友好的精确控制聚合，特别是在水中的活性阳离子和自由基聚合，这两者都被认为是不可能的。(1)以R-0H为引发剂，以耐水、高度亲氧的Lewis酸BF_3为引发剂，在水中实现了各种苯乙烯衍生物的阳离子聚合。聚合通过bf_3介导的C-OH末端可逆活化得到分子量可控、分子量分布窄的聚合物。在含有大量水的悬浮体系中，对甲氧基苯乙烯在受控的方式下聚合，得到了m.n bbb10 000和M_w/M_n ~ 1.5的聚合物。该引发体系也适用于对（氯甲基）苯乙烯的阳离子控制聚合，其中C-OH末端被BF_3选择性激活，而氯甲基官能团没有同时发生副反应。这些是控制阳离子聚合的前所未有的结果。耐水的铁和钌催化剂通过碳-卤素键的可逆活化，诱导了多种单体在水中的活性径向聚合。丙烯酸酯和苯乙烯的悬浮活性自由基聚合与半茂金属型铁配合物是可能的，并得到控制分子量至少高达M_n的聚合物。~ 100,000和窄mwd （M_w/M_n ~ 1.2）。离子膦或聚乙二醇基膦用于钌配合物导致甲基丙烯酸酯在水中的活性自由基聚合，并且易于从产品中去除催化剂。

This research was directed to development of environmentally friendly precision controlled polymerization, specifically living cationic and radical polymerization in water, both of which have been considered impossible.(1) Living Cationic Polymerization in WaterControlled cationic polymerization of various styrene derivatives was achieved in water with the use of an initiating system consisting of R-0H as an initiator and a water-tolerant and highly oxophilic Lewis acid, BF_3. The polymerization proceeded via BF_3-meidated reversible activation of C-OH terminal to give polymers with controlled molecular weights and narrow molecular weight distributions (MWDs). For a suspension system with a large amount of water, p-methoxystyrene was polymerized in a controlled fashion to yield polymers with M._n > 10,000 and M_w/M_n〜 1.5. The initiating system was also applicable for controlled cationic polymerization of p-(chloromethyl)styrene, where the C-OH terminal was selectively activated by BF_3 Without concurrent side-reactions of the chloromethyl functional groups. These are unprecedented results in controlled cationic polymerizations.(2) Living Radical Polymerization in WaterWater-tolerant iron and ruthenium catalysts induced living radial polymerization of a variety of monomers in water via reversible activation of a carbon-halogen bond. Suspension living radical polymerizations of acrylates and styrene were possible with a half-metallocene type iron complex and gave polymers with controlled molecular weights at least up to M_n. 〜 100,000 and narrow MWDs (M_w/M_n〜 1.2).The use of an ionic phosphine or polyethyleneglycol-based phosphine for ruthenium complexes led to living radical polymerization of methacrylates in water and easy removal of the catalysts from the products.