UNS:Predictive Ab Initio Dynamics in Zeolite Biofuel Production Catalysts: Towards More Gas and Less Coke

点击翻译按钮获取中文摘要

Auerbach (1512442) - The study involves theoretical calculations aimed at understanding the complex catalysis involved in converting biomass-derived organic compounds to liquid fuel precursors in the confined spaces of zeolites while avoiding deactivation due to coke formation. A novel theoretical approach will be employed that will be benchmarked against experimental data. The PI will also incorporate aspects of his research into educational and outreach programs including an immersive summer science experience for middle- and high-school girls.The proposal builds on recognition that selective conversion of biomass-derived organic species to longer-chain liquid fuel precursors and the undesired reaction to form coke, are both examples of carbon-carbon bond forming reactions, and thus amenable to theoretical methods that provide insight into fundamental mechanisms of carbon chain growth as affected by zeolite structure and chemical properties. Thus, the proposed work addresses both phenomena, but through a unique theoretical approach - "metadynamics in reverse" - by examining the more-straightforward carbon-carbon bond breaking process and appealing to microscopic reversibility to gain insight into the carbon addition reactions. To this end, the PI will employ and extend several aspects of computational catalysis developed in his lab (in collaboration with the software firm SCHROEDINGER) to obtain accurate energetics of carbon bond forming and breaking while incorporating effects of framework dynamics and long-range forces, all while keeping simulation times manageable. Specifically, the work will address how confinement effects in the zeolite cage influence the balance between the activation and condensation steps in aldol condensation. The theoretical predictions will be benchmarked against related experimental studies carried out by his collaborator, Paul Dauenhauer.The broader impact of the research is in the general insight it will provide on organic reactions in zeolite structures, especially the factors that control selectivity between condensation reactions to produce desired specific carbon-number products and unchecked carbon condensation to form coke. In addition to the direct insight into the aldol condensation process, the theoretical techniques that will be developed and refined should have broad applicability to reaction processes in the confined environment of zeolite cages. The PI has developed a strong education and outreach plan that incorporates aspects of his research while addressing studies showing that interest in science and math dwindles amongst girls during their middle-school years. He also directs an inter-disciplinary program for undergraduate students at U Mass Amherst that forms teams of students to address real-world scientific issues, especially those dealing with biomedicine and renewable energy.