CAREER: Reaction Kinetics Analysis of the Lebedev Process

职业：列别捷夫过程的反应动力学分析

• 批准号: 2046812
• 负责人: Thomas Schwartz
• 金额: $ 51.4万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-01 至 2026-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2046812&HistoricalAwards=false
• 关键词: CAREER; Reaction; Kinetics; Analysis; Lebedev

The project explores the potential of using biorenewable ethanol as an alternative to conventional petroleum resources for production of 1,3-Butadiene (BD) - an important chemical precursor used to produce synthetic rubbers utilized in car tires, paper coatings, textile backings, and adhesives. Recent shifts in petroleum resources have placed pressure on the BD market, opening the door to on-purpose production of BD. A particularly promising technology is the Lebedev process which manufactures BD from ethanol. However, the process relies on a complex, multicomponent catalyst and suffers from low product yields. The project will develop a molecular-level picture of the reaction network used to produce BD from ethanol, which in turn is important for developing new catalysts that can achieve high BD yields. Thus, the project has potential to ensure security and U.S. competitiveness in BD production while supporting the clean-energy transition to biorenewable feedstocks. Additionally, the investigator will develop new course materials to teach undergraduate students about catalytic reactor design and biobased chemicals production. The project team will also develop a module to educate high school students and the public about the production of renewable chemicals from woody biomass.Following on the early work of Union Carbide, many groups have used MgO-SiO2 as a low-cost platform from which to develop next-generation catalysts for the Lebedev process. However, to date a rigorous reaction kinetics analysis of BD production by MgO-SiO2 has not been performed. Based on recently published results from the investigator’s team, coupled with observations in the literature, the rate of BD formation over pure MgO-SiO2 catalysts is hypothesized to be controlled by ethanol dehydrogenation, while selectivity to BD in the presence of transition metal promoters is hypothesized to result from C-C bond formation catalyzed by acid-base site pairs. The literature is conflicted about the C-C coupling mechanism and the nature of the requisite active sites, which the study will clarify in three main thrusts. First, steady-state reaction kinetics measurements using model MgO-SiO2 catalysts containing specific types of acid-base site pairs will be used to identify rate-controlling steps and to clarify which sites are responsible for the kinetically significant reactions in BD production. Next, these catalysts will be spectroscopically characterized by FTIR, XPS, LEIS, and SSNMR to identify site requirements and abundant surface intermediates. Finally, a microkinetic model will be used to unify the macroscopic kinetics observations with mechanistic insight provided by kinetic isotope effect and isotope tracer studies and DFT calculations.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.

该项目探讨了使用生物可再生乙醇作为传统石油资源的替代品生产1，3-丁二醇（BD）的潜力-这是一种重要的化学前体，用于生产汽车轮胎，纸张涂层，纺织品背衬和粘合剂中使用的合成橡胶。 最近石油资源的变化给BD市场带来了压力，为BD的专门生产打开了大门。 一个特别有前途的技术是Lebedev工艺，它从乙醇中生产BD。 然而，该方法依赖于复杂的多组分催化剂，并且产品收率低。 该项目将开发用于从乙醇生产BD的反应网络的分子水平图像，这反过来对于开发可以实现高BD产率的新催化剂非常重要。 因此，该项目有可能确保BD生产的安全性和美国的竞争力，同时支持清洁能源向生物可再生原料的过渡。此外，研究人员将开发新的课程材料，教授本科生关于催化反应器设计和生物基化学品生产。 该项目团队还将开发一个模块，向高中生和公众介绍如何从木质生物质中生产可再生化学品。继联合碳化物公司的早期工作之后，许多集团已经使用MgO-SiO2作为低成本平台，开发用于列别捷夫工艺的下一代催化剂。 然而，迄今为止，还没有进行严格的反应动力学分析的BD生产的MgO-SiO2。 根据最近发表的研究结果，再加上文献中的观察，BD形成的纯MgO-SiO2催化剂的速率被假设为控制乙醇脱氢，而在过渡金属促进剂的存在下，BD的选择性被假设为导致从C-C键的形成由酸碱位点对催化。 文献中关于C-C偶联机制和所需活性位点的性质存在冲突，本研究将从三个方面澄清。 首先，稳态反应动力学测量使用模型MgO-SiO2催化剂含有特定类型的酸碱位点对将被用来确定速率控制步骤，并澄清哪些网站是负责BD生产中的动力学显着的反应。 接下来，这些催化剂将通过FTIR，XPS，LEIS和SSNMR进行光谱表征，以确定位置要求和丰富的表面中间体。 最后，一个微观动力学模型将用于统一宏观动力学观测与动力学同位素效应和同位素示踪研究和DFT计算提供的机制洞察力。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。