Degree Type

Dissertation

Date of Award

2009

Degree Name

Doctor of Philosophy

Department

Chemical and Biological Engineering

First Advisor

Brent H. Shanks

Abstract

Understanding of the catalytic domains within porous catalysts is essential for control of these systems in order to obtain desired reaction yields and selectivities. This body of work consists of studies on two types of porous catalysts, mesoporous silica and zeolites, that can have interesting cooperative catalytic interactions between the inorganic framework and organic molecules within the catalyst. Mesoporous silica materials, the main focus of this work, have controllable pore sizes and can be tailored to a specific reaction by covalent functionalization with a variety of organic functional groups in different spatial distributions. Zeolites, on the other hand, have pores that are generally too small to be functionalized covalently with organic groups. However, these materials can also become organic-inorganic hybrid catalysts of a different type when molecules are trapped within the pores and participate in reactions.

New co-condensed organic base-functionalized SBA-15 catalysts were synthesized and characterized and then demonstrated activity with a Michael reaction. These materials were then used in a Knoevenagel condensation to examine acid-base cooperativity between the amines and the silica surface hydroxyl groups. The results obtained demonstrated that acid-base cooperativity seen in the literature for isolated sites in silica gel can also be demonstrated on an extended catalytic domain on the surface of mesoporous silica, where the active sites are distributed randomly.

The focus of the zeolite study is on the hydrocarbon pool mechanism of the alcohols-to-gasoline process within the pores of H-ZSM-5. Many studies of this mechanism using methanol as the feed to this process have been done, but the hydrocarbons retained within the pores during the course of the reaction when other alcohols and alcohol mixtures are used as feeds have not been reported in the literature. The goals of this study are to gain insight into the reaction mechanism, which is still not well understood and to see how what changes occur when different feeds are used.

Copyright Owner

Sarah Lynn Hruby

Language

en

Date Available

2012-04-30

File Format

application/pdf

File Size

145 pages

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