Catalytic Deoxydehydration of Biomass-Derived Polyols to Olefins

摘要#1160219P.I.：Friederke C.Jentoft将生物质转化为可替代燃料或有用的化学中间体(如烯烃)所需的关键化学转化的特点是有效地脱氧，理想情况下不会显著损失碳。一种方法是使用几个催化转化过程来实现这一点，允许每个过程都根据所使用的催化剂进行优化。多元醇是一种具有多种羟基官能团的分子，在已知的转化过程中很容易从纤维素生物质中获得。俄克拉荷马大学的首席研究员Friederke C.Jentoft和Kenneth M.Nicholas提议开发新型的多相催化剂，将生物质衍生的多元醇底物在液体亲水介质中转化。目标反应是脱氧脱水，即氧和水将分别通过还原和脱水同时去除。本项目的主要目的是开发负载型氧金属络合物催化剂，用于多元醇脱氧制烯烃的反应，并对反应过程中涉及的活性氧金属物种进行鉴定，并阐明反应机理。项目的实现？S的目标将通过化学与生物化学系的尼古拉斯小组和化学、生物与材料工程学院的Jentoft小组之间的协同互动来促进。这些小组将有机金属化学和均相催化方面的专业知识与多相催化和光谱学方面的专业知识结合在一起。PIS将探索一系列催化剂组成，氧配合物的候选过渡金属是Re、钼和钒，候选载体是活性碳、CeO_2和层状双氢氧化物。将以亚硫酸盐和分子氢为还原剂，在各种条件和溶剂中测试这些材料对多元醇脱氧脱水的催化活性、选择性和稳定性。催化脱氧过程中的关键步骤将通过光谱监测脱氧脱水剂和乙二醇与活性载体氧-金属络合物的相互作用来阐明。该研究项目的成功实施将：1)建立一种新的、潜在有用的化学转化纤维素和乙醇酸的原料，用于可持续地制备可通过现有工艺进一步转化的增值不饱和产品和中间体；2)提供涉及碳水化合物/多元醇物质、负载金属氧物种、实用还原剂和合适的反应介质的化学反应的基本知识和理解；以及3)为本科生和研究生以及博士后研究人员提供催化关键学科的前沿跨学科教育和技术培训。

ABSTRACT#1160219P.I.: Friederike C. JentoftThe key chemical transformations that are needed in the conversion of biomass into fungible fuels or useful chemical intermediates, such as olefins, are characterized by effectively removing oxygen ideally without significant loss of carbon. One approach would be to achieve this employing several catalytic conversion processes, allowing each to be optimized in terms of catalyst employed. Polyols, molecules with multiple OH functionalities, are easily obtainable from cellulosic biomass in known conversion processes. Principal investigators Friederike C. Jentoft and Kenneth M. Nicholas of the University of Oklahoma are proposing to develop novel, heterogeneous catalysts that will convert biomass-derived polyol substrates in liquid phase, hydrophilic media. The target reaction is a deoxydehydration, that is, oxygen and water will be removed simultaneously by reduction and dehydration, respectively. With the help of a sacrificial reducing agent, the net loss of two OH groups from the polyol can be effected, and a versatile olefinic product is obtained.The primary objectives of this project are to develop supported oxo-metal complexes as catalysts for the deoxydehydration of polyols to olefinic products, to identify the reactive oxo-metal species involved in these processes and to elucidate the reaction mechanism. Achievement of the project?s objective will be facilitated by the synergistic interaction between the Nicholas group in the Department of Chemistry & Biochemistry and the Jentoft group in the School of Chemical, Biological and Materials Engineering. The groups combine expertise in organometallic chemistry and homogeneous catalysis with expertise in heterogeneous catalysis and spectroscopy. The PIs will explore an array of catalyst compositions, with candidate transition metals for the oxo-complexes being rhenium, molybdenum and vanadium, and candidates for supports being activated carbon, ceria, and layered double hydroxides. The catalytic activity, selectivity and stability of these materials for deoxydehydration of polyols will be tested using sulfites and molecular hydrogen as reducing agents and a variety of conditions and solvents. The key steps in the catalytic deoxydehydration processes will be elucidated by spectroscopically monitoring the interaction of deoxydehydration reductants and glycols with active supported oxo-metal complexes. Successful execution of this research project will: 1) establish a new, potentially useful, chemical transformation of cellulosic- and glycolic feedstocks for the sustainable preparation of value-added unsaturated products and intermediates that can be further converted by existing processes; 2) provide fundamental knowledge and understanding of chemical reactions involving carbohydrate/polyol substances, supported metal-oxo species, practical reductants, and suitable reaction media; and 3) supply cutting-edge cross-disciplinary educational and technical training in the key discipline of catalysis for undergraduate and graduate students as well as for postdoctoral researchers.