Collaborative Research: Photoelectrosynthetic Aminoxyl Catalyzed Alcohol Oxidation

合作研究：光电化学氨氧基催化酒精氧化

• 批准号: 2234090
• 负责人: Clara Choi
• 金额: $ 1.12万
• 依托单位: The University of Texas Rio Grande Valley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2234090&HistoricalAwards=false
• 关键词: Collaborative; Research; Photoelectrosynthetic; Aminoxyl; Catalyzed

Lignocellulosic biomass offers a carbon-neutral alternative source of fuels and chemicals which are currently sourced from petroleum and other fossil fuels. Converting lignin, a largely underutilized yet chemically rich byproduct of the biorefining industry, to valuable aromatic platform chemicals is an energy-intensive process that has made this approach cost prohibitive. Recently, dye-sensitized photoelectrosynthetic cells (similar to photovoltaic cells) have emerged as a low-cost and environmentally friendly technology for converting solar energy into chemical fuels or electricity. These photoelectrochemical cells offer a means of using renewable solar energy to drive energy-intensive chemical conversions at ambient temperature and pressure. Here, the collaborative fundamental research project will study how a dye-sensitized photoanode can chemoselectively oxidize lignin with a suitable catalyst as a first step toward a complete light-driven lignin depolymerization process. This approach will expand on the use of heterogeneous catalysis for the oxidation of primary and secondary alcohols to produce carbonyl or carboxyl compounds for the fine chemical and pharmaceutical industries. This work represents a new application for dye-sensitized photoelectrosynthetic cells, and the research findings from the project will be disseminated to the public through research publications, conference presentations, and by organizing and hosting educational outreach programs for future professionals in the STEM field. The PIs will also actively recruit and support underrepresented minority students through the outreach program.Organic oxidation reactions are important in organic synthesis or lignocellulosic biomass processing. Chemoselective oxidation of the aliphatic and/or benzylic alcohol moieties in lignin is a good target for controlling the degradation of lignin to generate desired small molecular products. This project aims to elucidate a photoelectrosynthetic chemoselective oxidation of alcohol moieties in lignin by combining the use of aminoxyl mediators with a dye-sensitized photoanode (DSP) at room temperature. Essential to this approach is the use of a dye-sensitized electrode interface to activate a nitroxyl mediator via light-induced charge separation. This presents both a new approach for driving the photochemical oxidation of the secondary benzylic alcohol and the primary aliphatic alcohol functional groups found in lignin, as well as a new photocatalytic application for dye-sensitized photoelectrosynthetic cells, which have traditionally focused on solar water splitting. The approach will involve (1) the synthesis of photoactive polymeric catalysts and the elucidation of their underlying photochemical electron transfer properties for activating nitroxyl mediators, (2) the fabrication and evaluation of mesoporous semiconductor-based electrodes specifically designed for the chemoselective oxidation of lignin dimer model compounds with a series of nitroxyl mediators, and (3) the elucidation of mechanistic pathways for the light-driven oxidation of 2o benzylic and 1o aliphatic alcohols using a DSP and address practical challenges presented by the use of oligomer model compounds and technical lignin. This research is significant as a first test case of a DSP to carry out the selective oxidation of real lignin at room temperature as a first step toward light-driven biomass conversion to value-added chemicals.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

木质纤维素生物质提供了目前来源于石油和其他化石燃料的燃料和化学品的碳中性替代来源。将木质素转化为有价值的芳族平台化学品是一种能源密集型过程，这使得这种方法成本过高。最近，染料敏化光电合成电池（类似于光伏电池）已经成为一种低成本和环境友好的技术，用于将太阳能转化为化学燃料或电力。这些光电化学电池提供了一种利用可再生太阳能在环境温度和压力下驱动能源密集型化学转化的方法。在这里，合作基础研究项目将研究染料敏化光阳极如何用合适的催化剂化学选择性氧化木质素，作为完成光驱动木质素解聚过程的第一步。这种方法将扩大使用多相催化的伯和仲醇的氧化，以产生羰基或羧基化合物的精细化工和制药工业。这项工作代表了染料敏化光电合成电池的新应用，该项目的研究成果将通过研究出版物，会议演示以及为STEM领域未来的专业人士组织和举办教育推广计划向公众传播。PI还将通过外展计划积极招募和支持代表性不足的少数民族学生。有机氧化反应在有机合成或木质纤维素生物质加工中非常重要。木质素中脂肪醇和/或苄醇部分的化学选择性氧化是控制木质素降解以产生所需小分子产物的良好目标。本项目旨在阐明一个光电合成化学选择性氧化的醇部分在木质素相结合的使用氨氧基介体与染料敏化光阳极（DSP）在室温下。这种方法的关键是使用染料敏化电极界面，通过光诱导电荷分离来激活硝酰基介体。这既提出了一种新的方法，用于驱动的仲苄醇和伯脂肪醇官能团中发现的木质素的光化学氧化，以及一个新的光催化应用染料敏化光电合成电池，传统上集中在太阳能水分解。该方法将涉及（1）光活性聚合物催化剂的合成和它们用于活化硝酰基介体的潜在光化学电子转移性质的阐明，（2）专门设计用于具有一系列硝酰基介体的木质素二聚体模型化合物的化学选择性氧化的基于介孔催化剂的电极的制造和评价，和（3）阐明了使用DSP光驱动氧化2 o苄基和10脂肪醇的机理途径，并解决了使用低聚物模型化合物和工业木质素所带来的实际挑战。这项研究是DSP的第一个测试案例，在室温下进行真实的木质素的选择性氧化，作为光驱动生物质转化为增值化学品的第一步。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。