Development of tandem catalytic systems utilizing mesoporous silica nanoparticles

Carboxylic esters are important precursor molecules in many industries such as pharmaceuticals, polymers, food additives, and fine chemical synthesis. Tandem catalysis can be used to increase yields and selectivity for these important chemicals while also creating a greener reaction environment than is currently used to synthesize these molecules. Using mesoporous materials, mesoporous silica nanoparticles, specifically, as supports and compartmentalization tools in tandem catalysis can increase recyclability and durability, making an even more efficient and green catalytic system. MSN makes an ideal support for tandem catalysis because of its high surface area, tunable pore sizes, and chemical and thermal stability. Herein, mesoporous silica nanoparticles are used as supports in tandem catalytic systems, leading to the first MSN supported tandem catalyst to combine enzymes and inorganic catalysts together in the same system. With the large pore size of MSN, more than one catalyst can be loaded into the pores and onto the support surface, utilizing the unique surface within the pores. A wet impregnation method has been used to load palladium and gold nanoparticles onto MSN for the direct oxidative esterification of allyl alcohol. The tandem catalyst was then coated with a polydopamine polymer coating to prevent leaching of the metal nanoparticles while simultaneously increasing recyclability of the catalyst. A co-condensation method was used to functionalize MSN with evenly distributed functional groups while maintaining the ordered pore morphology by altering the pre-hydrolysis time as well as the hydrothermal treatment temperature. Amine functionalized MSN has shown to be an effective chemical handle for attaching biomolecules that retain activity and are able to be recycled multiple times. These two studies were then combined to create the first tandem catalyst supported on MSN that combined enzymes and inorganic catalysts in a one-pot system. This catalyst retained activity over multiple cycles for the direct oxidative esterification of ally alcohol in mild reaction conditions. Both fundamental and applied aspects of tandem catalytic systems using MSN supports were explored to gain insight into how they can be applied into small- and large-scale reactions.

Name thesis:degree_name

Doctor of Philosophy (Ph.D.)

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Chemistry

Grantor dc:publisher

Colorado School of Mines. Arthur Lakes Library

Year dc:date.issued

2022

Author dc:creator

• Metzger, Kara E.

Advisor dc:contributor.advisor

• Trewyn, Brian

Committee members dc:contributor.committeemember

• Shafer, Jenifer C.
• Posewitz, Matthew C.
• Ramey, C. Josh

• enzymes
• mesoporous silica nanoparticles
• tandem catalysis

Statement dc:rights

• Copyright of the original work is retained by the author.

Language dc:language.iso

eng, English

Identifier

T 9334

OAI identifier oai:identifier

oai:repository.mines.edu:11124/15417