SusChEM: Stereoselective Polymerization of Biomass Monomers by Transition-Metal and Organic Catalysts

化学催化项目支持科罗拉多州立大学的Eugene Y. Chen教授研究新的立体选择性聚合体系，通过手性过渡金属和有机催化剂，以催化方式从生物质衍生的丙烯酸单体合成高价值的立体规则和手性聚合物或光学分解化学品。采用合成、催化、机理和计算方法来实现三个特定目标：(1)通过手性过渡金属催化剂的分子工程建立生物质丙烯酸的立体选择聚合；(2)通过手性离子对促进氢化物穿梭聚合，实现生物质丙烯酸酯的催化聚合和体积丙烯酸酯的催化不对称聚合；(3)通过内链和外链转移途径发展丙烯酸的催化和不对称有机聚合以及手性有机催化剂的利用。多样化的实验技术与国际合作相结合，带来了互补的理论专业知识。该项目属于SusChEM倡议，因为它利用非石油为基础的原料（如植物生物质）来生产潜在的商品规模产品。这项研究为学生提供了广泛的催化和聚合物材料技术的培训和教学机会，这些领域对全球经济至关重要。学生还将学习可持续发展，为他们解决全球问题和在未来的专业工作场所发挥领导作用提供坚实的基础。化学催化项目支持科罗拉多州立大学的Eugene Y. Chen对金属和有机催化的丙烯酸聚合的研究。金属催化路线与传统的（阴离子或自由基）丙烯酸聚合在三个方面不同：(a)它是催化剂位置控制，因此分子催化剂可以在室温下以高精度合成各种聚合物；(b)确保每个单体具有相同的手性诱导度，从而产生均匀的手性聚合物；(c)催化循环可以通过内部或外部过程来构建，用于催化生产立体规则或手性聚合物。有机催化途径体现了可持续/绿色化学的几个关键原则：它只使用少量相对无毒的有机催化剂，在室温下不到1分钟的反应就能迅速将所有单体转化为高分子量的生物塑料。从技术角度来看，这两种聚合系统都可以在经济可行的条件下运行（例如，在较低的温度和催化方式下），并使用可再生原料生产技术上重要的立体规则或手性聚合物，这不仅提供了石油基聚合物的可持续替代品，而且具有优越的材料性能。陈教授正在为高年级本科生和研究生编写一本关于“可持续化学”的新教材。这篇文章设想用于教育化学和化学工程的学生，以及在化学可持续发展的中心作用的一般公众。

The Chemical Catalysis Program supports the efforts of Professor Eugene Y. Chen of Colorado State University in the investigation of new stereoselective polymerization systems by chiral transition-metal and organic catalysts for the synthesis of high-value stereoregular and chiral polymers or optically-resolved chemicals from biomass-derived acrylic monomers in a catalytic fashion. Synthetic, catalytic, mechanistic, and computational methods are employed to accomplish three specific objectives: (1) establishing stereoselective polymerization of biomass acrylics through molecular engineering of chiral transition-metal catalysts; (2) advancing hydride-shuttling polymerizations promoted by chiral ion pairs to enable catalytic polymerization of biomass acrylics and catalytic asymmetric polymerization of bulky acrylics; and (3) developing catalytic and asymmetric organopolymerizations of acrylics via internal and external chain transfer routes and utilization of chiral organic catalysts. Diverse experimental techniques are coupled with international collaborations that bring in complementary theoretical expertise. This project falls under the SusChEM initiative as it utilizes non-petroleum based starting materials (e.g., plant biomass) for the production of potential commodity-scale products. This research provides educational opportunities for training and teaching of students with a wide range of techniques in catalysis and polymeric materials, areas central to the global economy. Students also learn about sustainability, providing them with a strong basis to address global problems and play leadership roles in their future professional workplaces.The Chemical Catalysis Program supports the efforts of Eugene Y. Chen of Colorado State University for the investigation of metal-and organically-catalyzed polymerization of acrylics. The metal-catalyzed route departs from conventional (anionic or radical) acrylic polymerizations in three ways: (a) it is catalyst site-controlled so that molecular catalysts can be engineered for the synthesis of a wide range of polymers with high precision at room temperature; (b) it ensures the same degree of chiral induction for each monomer to produce uniform chiral polymers; and (c) catalytic cycles can be constructed by internal or external processes for catalytic production of stereoregular or chiral polymers. The organocatalysis route exhibits characteristics that embody several key principles of sustainable/green chemistry: it employs only a small amount of the relatively non-toxic organic catalyst and rapidly converts all monomers to high molecular weight bioplastics in less than 1 min of reaction at room temperature. From a technological point of view, both polymerization systems can be operated under economically viable conditions (e.g., at lower temperatures and in a catalytic fashion) and produce technologically important stereoregular or chiral polymers using renewable feedstocks, which offer not only sustainable alternatives to petroleum-based polymers, but also superior materials properties. Professor Chen is preparing a new textbook for senior undergraduate and graduate level students on the "Chemistry of Sustainability". This text is envisioned for use in educating chemistry and chemical engineering students as well as the general public in the central role of chemistry in sustainability.