Water-Assisted Oxygen Insertion Reactions Over Supported Gold Catalysts

负载型金催化剂上的水辅助氧插入反应

• 批准号: 1465184
• 负责人: Lars Grabow
• 金额: $ 20.1万
• 依托单位: University of Houston
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1465184&HistoricalAwards=false
• 关键词: Water; Assisted; Oxygen; Insertion; Reactions

Due to recent advances in shale gas production, increased natural gas recovery, and reduced natural gas prices, the United States has an abundance of cheap natural gas. Methane, the primary component of natural gas, has found widespread use as a fuel for electricity generation; however it is not a good feedstock for the production of chemicals or transportation fuels such as gasoline or diesel. This stems from the difficulty in selectively oxidizing methane by insertion of an oxygen atom into a strong carbon-hydrogen bond while preventing the complete combustion to carbon dioxide and water. Gold is known to be inert when exposed to oxygen or air, but when it divided into small nanoparticles, it starts to catalyze the oxidation of carbon monoxide. Dr. Grabow of the University of Houston and Dr. Chandler of Trinity University have recently discovered a mechanism whereby water acts as a co-catalyst during CO oxidation over gold nanoparticles supported on titanium-oxide. They are now translating this knowledge to enable the partial oxidation of methane and other alkanes to form the corresponding alcohol. The team follows a collaborative and tightly coupled approach using computational and experimental studies to quantify the promotional effect of water on selective oxidation and to investigate the dominant reaction mechanism for oxygen insertion into carbon-hydrogen bonds. With over 7.72 trillion m3 of confirmed natural gas reserves, there is a huge incentive to develop commercially-viable methane conversion processes to benefit the U.S. economy and achieve national energy independence. The research activities are integrated with broad-reaching educational efforts at the K-12, undergraduate, graduate and professional level to broaden the participation of minority students and increase the retention of at-risk students at both participating universities. The University of Houston is a designated Hispanic-Serving Institution and has the most ethnically balanced student body of all major research institutions in the U.S. Trinity University provides research active undergraduate education to San Antonio and the South Texas region, which are largely populated by a traditionally underrepresented group in the STEM disciplines. Together, the principal investigators have a strong record for mentoring research projects for undergraduate, minority and female students.Dr. Lars Grabow of the University of Houston and Dr. Bert Chandler of Trinity University are funded by the Chemical Catalysis Program at NSF to study oxygen insertion reactions into carbon-hydrogen (C-H) bonds over supported gold catalysts. The ultimate goal is to convert methane to methanol selectively, and a rational approach to the problem requires the close integration of theoretical (Grabow) and experimental (Chandler) techniques. The prevailing challenge in all processes using methane as a feedstock is activating the strong C-H bond; hence, the initial focus is on higher alkanes with weaker C-H bonds to acquire pertinent knowledge about the oxygen (O) insertion mechanism. To realize the possibility of using small amounts of water to improve the activity and selectivity of oxidation reactions over supported gold (Au) catalysts, the team quantifies the amount of surface water on different supports, investigates the dominant reaction mechanism for oxygen insertion into C-H bonds, and improves the product yield as guided by computational predictions. The selected application, O insertion into C-H bonds of alkanes, is a challenging fundamental problem in chemistry with far reaching technological impact for upgrading of natural gas to benefit the U.S. economy and achieve national energy independence. This concept can also be extended to other difficult selective oxidation reactions, e.g. ethylene epoxidation. Research activities are integrated with broad-reaching educational efforts at the K-12, undergraduate, graduate and professional level to broaden the participation of minority students and increase the retention of at-risk students at both participating universities. Together, the principal investigators have a strong record for mentoring research projects for undergraduate, minority and female students.

由于近年来页岩气生产的进步、天然气采收率的提高和天然气价格的下降，美国拥有丰富的廉价天然气。甲烷是天然气的主要成分，已被广泛用作发电燃料；然而，它不是生产化学品或运输燃料（如汽油或柴油）的良好原料。这是因为很难通过在强碳氢键中插入氧原子来选择性氧化甲烷，同时防止完全燃烧成二氧化碳和水。众所周知，金在暴露于氧气或空气中时是惰性的，但当它分裂成小的纳米颗粒时，它开始催化一氧化碳的氧化。休斯顿大学的格拉博博士和三一大学的钱德勒博士最近发现了一种机制，即在氧化钛支撑的金纳米颗粒上，水作为CO氧化的助催化剂。他们现在正在将这一知识转化为甲烷和其他烷烃的部分氧化，从而形成相应的醇。该团队采用协作和紧密耦合的方法，使用计算和实验研究来量化水对选择性氧化的促进作用，并研究氧插入碳氢键的主要反应机制。美国已确认的天然气储量超过7.72万亿立方米，开发商业上可行的甲烷转化工艺有利于美国经济，并实现国家能源独立，这是一个巨大的动力。这些研究活动与K-12、本科、研究生和专业水平的广泛教育工作相结合，以扩大少数民族学生的参与，并增加两所参与大学的高危学生的留校率。休斯顿大学是一所指定的西班牙裔服务机构，是美国所有主要研究机构中种族最平衡的学生群体。三一大学为圣安东尼奥和南德克萨斯地区提供研究型本科教育，这些地区主要由传统上在STEM学科中代表性不足的群体组成。两位主要研究人员在指导本科生、少数族裔学生和女学生的研究项目方面有着良好的记录。休斯顿大学的Lars Grabow和三一大学的Bert Chandler博士是由美国国家科学基金会的化学催化项目资助的，他们研究了负载型金催化剂上碳氢键（C-H）的氧插入反应。最终目标是选择性地将甲烷转化为甲醇，而解决这个问题的合理方法需要理论（格拉博）和实验（钱德勒）技术的紧密结合。在所有使用甲烷作为原料的过程中，主要的挑战是如何激活强碳氢键；因此，为了获得氧(O)插入机理的相关知识，最初的重点是具有较弱C-H键的高级烷烃。为了实现使用少量水来提高负载金（Au）催化剂上氧化反应的活性和选择性的可能性，该团队量化了不同载体上地表水的数量，研究了氧插入C-H键的主要反应机制，并在计算预测的指导下提高了产物收率。所选择的应用，O插入烷烃的C-H键，是一个具有挑战性的化学基本问题，对天然气升级具有深远的技术影响，有利于美国经济和实现国家能源独立。这个概念也可以推广到其他困难的选择性氧化反应，如乙烯环氧化。研究活动与K-12、本科、研究生和专业水平的广泛教育工作相结合，以扩大少数民族学生的参与，并增加两所参与大学的高危学生的留校率。两位主要研究人员在指导本科生、少数族裔学生和女学生的研究项目方面有着良好的记录。