Theses and Dissertations at Montana State University (MSU)
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Item A structural analysis of zeolite-templated carbons(Montana State University - Bozeman, College of Letters & Science, 2022) Taylor, Erin Elizabeth; Chairperson, Graduate Committee: Nicholas P. StadieZeolite-templated carbons (ZTCs) are a distinct class of porous framework materials comprised of a three-dimensional pore network contained between atomically thin, polycyclic hydrocarbon walls. This class of materials arose from the goal to develop carbon- based frameworks with ordered, homogeneous microporosity (see Chapter 1), as opposed to activated carbons where the pore network is random. It has more recently been suggested that zeolite-templating may be a viable synthetic route to carbon schwarzites, an elusive class of theoretical materials, which follow triply periodic minimal surfaces and are predicted to have many fundamentally interesting properties. Herein we show that while experimentally synthesized ZTCs (see Chapters 2 and 3) are too amorphous to be considered schwarzites, understanding the current structural features of ZTCs may be the key to finally isolating a schwarzite via zeolite-templating. The experimentally relevant open- blade model developed in our work predicts paramagnetism of ZTC materials (see Chapter 5); superconducting quantum interference device measurements on archetypical ZTC materials confirms this prediction, highlighting the unique nature of spin polarization in porous carbon materials. While the current ZTC structure resembles an open-blade, generating a closed- tube schwarzite-like ZTC variant may be accessible by tuning the catalytic activity of the zeolite template pore walls. In Chapter 6, alkali metal exchange is explored as a route to strengthen cation-? interactions between the growing ZTC framework and zeolite template in an attempt to achieve a more schwarzite-like ZTC. LiY-templated ZTCs show beginning signs of conversion to a closed-tube structure. Lastly, recent benchmark computational studies suggest that nitrogen-doping of open-blade porous carbon surfaces has a significant, beneficial effect on the binding energy toward methane: a strengthening by up to 3 kJ mol -1 over pure carbon. The work presented in Chapter 7 identifies optimal conditions to achieve nitrogen-doped ZTCs with N-contents ranging from 0-9 at%. Therein, we show that indeed high-pressure (100 bar) methane adsorption characterization of nitrogen-doped ZTCs exhibit an increased methane binding energy of 1.3 kJ mol -1, validating the theoretical predictions.Item Solid acid catalysts for biomass and sugar upgrading to furans(Montana State University - Bozeman, College of Engineering, 2019) Romo, Joelle Elise; Chairperson, Graduate Committee: Stephanie Wettstein; Nathan V. Bollar, Coy J. Zimmermann and Stephanie G. Wettstein were co-authors of the article, 'Conversion of sugars and biomass to furans using heterogeneous catalysts in biphasic solvent systems' in the journal 'ChemCatChem' which is contained within this thesis.; Ting Wu, Xinlei Huang, Jolie Lucero, Jennifer L. Irwin, Jesse Q. Bond, Moises A. Carreon and Stephanie G. Wettstein were co-authors of the article, 'SAPO-34/5A zeolite bead catalysts for furan production from xylose and glucose' in the journal 'ACS omega' which is contained within this thesis.Platform chemicals derived from biomass provide a viable alternative to petroleum-based fuels, chemicals, and materials. The efficient production of chemical building blocks, such as 5-hydroxymethylfurufral (HMF) and furfural, requires an optimized catalyst and reaction system, as well as an efficient system in which catalysts and products can be easily recovered. While homogeneous acid catalysts have historically been a popular choice for furan production, additional safety, material, and corrosion considerations motivates the exploration of heterogeneous solid acid catalysts. Furthermore, biphasic reaction systems, which use an organic solvent to continuously extract products, have shown increased furan yields over aqueous and monophasic systems and can allow for easy product recovery if the boiling point is selected carefully. One class of heterogeneous catalysts known as zeolites, has unique potential for furfural and HMF production with its controlled acidic and structural properties. A novel SAPO- 34/5A zeolite bead is presented in this thesis, showing promise in catalyst design for activity, product selectivity, and stability. The combination of optimized solvent systems with carefully designed solid acid catalysts lays a framework for the progression of platform chemical production from biomass. Additionally, a comprehensive review of heterogeneous catalysts for furan production in biphasic systems is presented here, which informs decisions on optimized solvent selection.Item Adsorption capacity of SAPO-34 and ZSM-5 zeolites determined by breakthrough experiments(Montana State University - Bozeman, College of Engineering, 2016) Ilic, Boris; Chairperson, Graduate Committee: Stephanie WettsteinAlthough it has been known for over 50 years that zeolite frameworks are flexible, it has been only of recent that a systematic investigation into this phenomenon has begun. An area that has not been significantly explored is the affect that zeolite flexibility may have on adsorption capacities. In order to explore this, a flow system was built and assembled, and the system performance was verified by replicating literature ZSM-5/isobutane, ZSM-5/n-hexane, and SAPO-34/methanol adsorption isotherms. Different packing schemes (powders, mixtures, pellets) were studied and corresponding adsorption capacities were evaluated for accuracy and precision. It was found that zeolite powder pressed into pellets led to the lowest deviation from literature values and that larger crystal sizes may also lead to more accurate values. While further investigation into packing methods is recommended, the relatively accurate adsorption capacities that were acquired suggests that the established flow system has been built and calibrated correctly, and that further adsorption experiments probing the flexibility of the zeolite structure can begin.