CAREER: Rational Design of Nanoporous Catalysts for Carbonylation Reactions

每年，数百万吨的醇和羧酸（用于生产聚合物，食品添加剂，溶剂和药物）通过催化羰基化进行工业生产。由于该工艺使用昂贵的稀有金属催化剂，并需要腐蚀性化学试剂来促进所需的反应，因此反应器设计严格且昂贵，催化剂回收方案复杂，废物流对环境不友好。该项目旨在发现有效的多孔固体酸催化剂作为技术和环境吸引力的替代品。然而，设计一种最佳的固体酸是一项具有挑战性的任务，因为有数百种潜在的结构可供选择，每种结构都具有独特的分子级空腔，可以稳定或防止不同的反应。该项目将开发计算机模型，使我们能够准确预测将发生哪些化学反应，从而实现催化剂设计的计算效率。这些发展将积极影响基于羰基化化学的制造工艺，以及为现代社会创造化学产品的许多其他大规模工业工艺。研究工作与教育和推广活动紧密结合，以服务于我们的总体目标，即提高下一代劳动力培训的计算能力，促进STEM领域的多样性和扩大代表性不足的学生的参与。最近的实验工作表明，具有8元环的纳米多孔沸石可以潜在地催化羰基化反应，具有高选择性，为传统的基于稀有金属的催化剂体系提供了令人信服的替代方案。尽管诱人的潜力，根本上重要的问题仍然存在，包括：什么是结构图案，这将使可能有效的羰基化小甲氧基基团与较大的碳阳离子在不同的沸石架构？如何通过选择性抑制不需要的反应来控制酸催化的副反应？在这些奈米多孔固体酸中，促进剂与毒物的作用机制为何？该研究计划将通过开发和应用集成量子化学和基于力场的分子尺度模拟的计算工具来解决这些问题。该项目将产生对纳米多孔催化剂中限制效应的基本见解，并将使选择性靶向反应的催化剂的合理设计成为可能。成功的结果不仅可以导致用于合成乙醇和乙酸的工业上可行的、环境友好的固体酸，而且还提供了在其他有机合成中使用固体酸和在许多现有的、大-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。

Annually, millions of tons of alcohols and carboxylic acids (used to create polymers, food additives, solvents, and pharmaceuticals) are produced industrially via catalytic carbonylation. Because this process makes use of expensive rare-metal catalysts and requires corrosive chemical agents to promote the desired reactions, the result is stringent and costly reactor designs, complex catalyst recycling schemes, and environmentally unfriendly waste streams. This project aims to discover effective porous solid-acid catalysts as a technologically and environmentally appealing alternative. Designing an optimal solid acid, however, is a challenging task, as there are hundreds of potential structures to choose from, each with unique, molecular-scale cavities that can stabilize or prevent different reactions. This project will develop computer models that allow us to make accurate predictions of which chemical reactions will take place, enabling a computationally efficient approach to catalyst design. These developments will positively impact manufacturing processes based on carbonylation chemistry, and also many other large-scale industrial processes that create the chemical products for our modern society. The research efforts are closely integrated with educational and outreach activities to serve our overarching goals of improving computational competency in the training of the next-generation workforce and promoting diversity and broadening participation of underrepresented students in STEM fields.Recent experimental work has demonstrated that nanoporous zeolites with 8-membered rings can potentially catalyze the carbonylation reaction with high selectivity, providing a compelling alternative to traditional rare metal-based catalyst systems. Despite the tantalizing potential, fundamentally important questions remain, including: What are the structural motifs that will make possible effective carbonylation of small methoxy groups versus larger carbocations in different zeolite architectures? How can acid-catalyzed side reactions be controlled by selectively suppressing undesired reactions? What are the mechanisms that determine the function of promoters and poisoners in these nanoporous solid acids? This research program will address these questions by developing and applying computational tools that integrate quantum chemical and forcefield-based molecular-scale simulations. The project will generate fundamental insights into confinement effects in nanoporous catalysts and will make possible the rational design of catalysts that target reactions selectively. A successful outcome may not only lead to industrially feasible, environmentally friendly solid acids for the synthesis of ethanol and acetic acid, but also provide general strategies for using solid acids in other organic syntheses and for controlling side reactions in many existing, large-scale solid acid catalytic processes.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.