SusChEM: Catalytic lignin degradation

化学部的化学催化计划支持科里斯蒂芬森教授的研究。斯蒂芬森教授是密歇根大学的教员。 该项目的目标是开发可持续的光催化化学方法，用于生物质降解和再利用。据估计，目前林业和农业生产的生物质总量足以取代石油作为精细化学品的碳原料。斯蒂芬森集团正在开发降解和转化木质素的方法，木质素是世界上第二丰富的生物聚合物，是有价值的商品化学品。 木质素的高芳烃含量被转化为有用的原料，并补充可从纤维素中衍生的脂肪族化学品。这个研究重点是教授斯蒂芬森的教育计划的一个组成部分，为学生在他的实验室的培训机会。 此外，它提供了动手实验模块集成到一系列的推广元素，旨在从事高中学生在绿色化学和分子科学的令人兴奋的机会。斯蒂芬森小组的研究生和本科生学员接触到广泛的跨学科主题，如催化，光化学，可再生能源和流动化学。重点是使用电子转移引发的转化来促进木质素化学键的化学选择性C-O和C-C键断裂反应，这是位于有机金属化学、光化学和材料科学交叉点的可持续化学过程。这些操作简单的催化方法不需要专门的光化学设备，利用廉价和节能的LED进行照射。木质素降解的挑战是解决使用氧化和还原可见光介导的自由基化学的组合。该提案由三个具体目标组成：1）开发采用光氧化还原催化和电子穿梭剂的新的催化氧化方法; 2）开发新的可见光介导的还原C-O和C-C裂解方法; 3）实施目标1和2中开发的策略，以在连续流中降解商业木质素。这些目标推进了更广泛的可持续化学概念，而不影响反应效率和化学选择性。

The Chemical Catalysis program of the Division of Chemistry supports the research of Professor Corey Stephenson. Professor Stephenson is a faculty member at the University of Michigan. The goal of the project is to develop sustainable photocatalytic chemical methods for biomass degradation and repurposing. The total amount of biomass currently produced by the forestry and agricultural industries is estimated to be sufficient to replace petroleum as a carbon feedstock for fine chemicals. The Stephenson group is developing methods to degrade and convert lignin, the second most abundant biopolymer in the world, to valuable commodity chemicals. Lignin's high aromatic content is converted into useful feedstocks and complementing the aliphatic chemicals that can be derived from cellulose. This research focus is an integral component of Professor Stephenson's educational plans as a training opportunity for students in his laboratory. In addition, it provides hands-on experimental modules integrated into a series of outreach elements designed to engage high school students in the exciting opportunities in green chemistry and molecular sciences. Graduate and undergraduate trainees in the Stephenson group are exposed to a broad range of interdisciplinary topics, such as catalysis, photochemistry, renewable energy and flow chemistry. The focus is on using electron transfer-initiated transformations to promote chemoselective C-O and C-C bond cleavage reactions of lignin chemical linkages, processes for sustainable chemistry that are situated at the intersection of organometallic chemistry, photochemistry and materials science. These operationally simple, catalytic methods obviate the need for specialized photochemistry equipment, utilizing inexpensive and energy efficient LEDs for irradiation. The challenges of lignin degradation are addressed using a combination of oxidative and reductive visible light-mediated radical chemistry. The proposal consists of three specific aims: 1) development of new catalytic oxidation methods employing both photoredox catalysis and electron shuttling agents; 2) development of novel visible light-mediated reductive C-O and C-C cleavage methods; 3) implementation of the strategies developed in aims 1 and 2 toward the degradation of commercial lignin in continuous flow. The objectives advance the broader concept of sustainable chemistry without compromising reaction efficiency and chemoselectivity.