Loading...
Design and application of magnesium oxide catalysts to combat deactivation in liquid-phase systems
York, Allyson
York, Allyson
Citations
Altmetric:
Advisor
Editor
Date
Date Issued
2019
Date Submitted
Keywords
Collections
Research Projects
Organizational Units
Journal Issue
Embargo Expires
Abstract
Mechanisms of heterogeneous catalyst deactivation have been studied in depth over the past few decades since catalyst failure has costly consequences, especially at the industrial scale. Efforts to mitigate deactivation via various protective mechanisms have been explored, but most summative literature revolves around protecting catalysts used in gas-phase reactions. While heterogeneous catalysts degrade similarly in liquids as they do in gaseous conditions, there are some methods of protection that are particularly helpful at mitigating failure in liquid environments. The first chapter outlines the most common deactivating modes to catalysts in liquid-phase systems and explores the most effective ways in which they can be protected, wherein the second chapter explores the fundamental study of the application of carbon coatings to basic metal oxides to reduce water deactivation. Basic metal oxide catalysts such as magnesium oxide offer utility in a wide variety of applications from pharmaceuticals to fuel production. Magnesium oxide catalysts with different facets, such as (100) and (111), have been compared in various catalytic activity studies; the (111) facet has even been deemed “a catalytic playground”. Additionally, carbon coatings have recently emerged as a promising method to enhance metal oxide catalyst stability when acting as heterogeneous catalyst supports. These coatings are unique in that they impart stability at low carbon loadings while allowing substrate access to active species. Here we report the synthesis, characterization, and application of graphitic carbon-coatings on commercial MgO, MgO (111), and hydrotalcite for 2-pentanone condensation. These findings highlight the enhanced effectiveness of MgO (111) versus commercial MgO with respect to turnover number and condensation product yield. Additionally, adding a graphitic overcoat to these materials allows 2-pentanone access to active sites, while also retaining base site character, and even enhances trimer condensate production. These results provide insight into carbon coating as a method of enhanced metal oxide durability and pave the way for continued mechanistic investigations.
Associated Publications
Rights
Copyright of the original work is retained by the author.