Browsing by Author "Wettstein, Stephanie G."

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Composition analysis of canola and intermediate wheatgrass biomass and the effects of extraction
(BioResources, 2023-01) Johnsrude, Lauren M.; Scheffel, Aidan J.; Allen, Brett L.; Wettstein, Stephanie G.
Knowing the composition of biomass is critical for determining accurate yields of renewable chemicals and fuels; however, nonstructural components can affect the results of standard composition procedures, leading to inaccurate reactant amounts. To remove these nonstructural components, solvent extractions can be done, but the impact on composition values has not been well-reported. For this study, compositional analysis was performed on as-received canola (Brassica napus) and intermediate wheatgrass (Thinopyrum intermedium), as well as ethanol, water, and water/ethanol extracted biomasses. Water/ethanol extraction of the intermediate wheatgrass resulted in significantly lower xylose and both acid soluble and insoluble lignin amounts when compared to the as-received analysis. Since sugar was removed during the extractions, it is recommended to use the as-received composition values for glucuronoarabinoxylans; however, the extractives may interfere with the lignin analysis and therefore, the extracted lignin values are likely more reflective of the composition.
Conversion of sugars and biomass to furans using heterogeneous catalysts in biphasic solvent systems
(2018-09) Wettstein, Stephanie G.; Bollar, Nathan; Romo, Joelle; Zimmermann, Coy
Within the last decade, interest in using biphasic systems for producing furans from biomass has grown significantly. Biphasic systems continuously extract furans into the organic phase, which prevents degradation reactions and potentially allows for easier separations of the products. Several heterogeneous catalyst types, including zeolites, ion exchange resins, niobium‐based, and others, have been used with various organic solvents to increase furan yields from sugar dehydration reactions. In this minireview, we summarized the use of heterogeneous catalysts in biphasic systems for furfural and 5‐hydroxymethylfurfural production from the past five years, highlighting trends in chemical and physical properties that effect catalytic activity. Additionally, the selection of an organic solvent for a biphasic system is extremely important and we review and discuss properties of the most commonly used organic solvents.
The effect of solvent polarity on autocatalytic furfural production confirmed by multivariate statistical analysis
(2019-10) Romo, Joelle E.; Miller, Kyle C.; Sundsted, Tara L.; Job, Adam L.; Hoo, Karlene A.; Wettstein, Stephanie G.
Autocatalytic dehydration of xylose to furfural was studied in pure aqueous and monophasic organic/water mixtures to determine the effect reaction media and conditions have on conversion and yield. This study identified that the severity (Ro) of the reaction and polarity, as determined by the Hansen Solubility Parameter, δP, strongly correlate with xylose conversion and furfural yield. Increasing the Ro and δP increased both conversion and yield in pure aqueous and organic/water mixtures of sulfolane, γ‐butyrolactone, γ‐valerolactone, γ‐hexalactone, and tetrahydrofuran. Additionally, it was found that at a specified Ro and δP, similar conversions and yields were achieved using different combinations of time, temperature, and solvent mixture. Using principal component analysis and projection to latent structures, a semi‐empirical model was developed that provided estimates of xylose conversion and furfural yield over a range of experimental Ro and δP values.
Impact of Xylose on Dynamics of Water Diffusion in Mesoporous Zeolites Measured by NMR
(2021-09) Nelson, Madison L.; Romo, Joelle E.; Wettstein, Stephanie G.; Seymour, Joseph D.
Zeolites are known to be effective catalysts in biomass converting processes. Understanding the mesoporous structure and dynamics within it during such reactions is important in effectively utilizing them. Nuclear magnetic resonance (NMR) T2 relaxation and diffusion measurements, using a high-power radio frequency probe, are shown to characterize the dynamics of water in mesoporous commercially made 5A zeolite beads before and after the introduction of xylose. Xylose is the starting point in the dehydration into furfural. The results indicate xylose slightly enhances rotational mobility while it decreases translational motion through altering the permeability, K, throughout the porous structure. The measurements show xylose inhibits pure water from relocating into larger pores within the zeolite beads where it eventually is expelled from the bead itself.
Self-paced, Active Problem-Solving Using Immediate Feedback (IF-AT; Scratch-off) Forms in Large Classes
(2018-05) Wettstein, Stephanie G.
In-class example problems that students work out on their own using active problem-solving are typically well received and help the students better learn the material; however, they are difficult to enact in large classes with limited resources due to the number of questions received and the speed at which different students work through the problem. In a Junior-level mass transfer unit operations course, immediate feedback (IF-AT) forms were used to allow groups of four students to self-pace through in-class problems. The immediate feedback forms allowed students to check their progress, use cooperative learning to resolve their misconceptions, and ask the instructor questions only when truly stuck. In a class of 100 students, with one instructor and one teaching assistant, two problems were worked through, once in week 5 and the other in week 13, using the immediate feedback forms. Student and instructor feedback was highly positive.
Small pore zeolite catalysts for furfural synthesis from xylose and switchgrass in a γ-valerolactone/water solvent
(2015-02) Bruce, Spencer M.; Zong, Zhaowang; Chatzidimitriou, Anargyros; Avci, Leyla E.; Bond, Jesse Q.; Carreon, Moises A.; Wettstein, Stephanie G.
Small pore zeolites were evaluated as catalysts in the dehydration of xylose and biomass to furfural in a monophasic system of 90/10 γ-valerolactone (GVL)/water. Although the pore sizes were significantly smaller than the kinetic diameter of the sugars, furfural yields on the commercial SAPO-34 catalyst were 40% from xylose and 31% from switchgrass (considering total glucose and xylose moles). Furfural degradation with time was minimal. The SAPO-34 catalyst was recycled multiple times with only a 5% drop in furfural yield and no significant leaching of acid sites occurred. To our knowledge, this is the first time that real biomass has been converted with moderate yields to furfural using small pore zeolites.
Solubility of 2,5-Furandicarboxylic Acid in Pure and Mixed Organic Solvent Systems at 293 K Predicted Using Hansen Solubility Parameters
(American Chemical Society, 2024-07) Molinaro, Jacob M.; Carroll, M.; Marchan, Gabriela T.; Wettstein, Stephanie G.
Central to the production of polyethylene furanoate (PEF), a bioplastic that could potentially replace petroleum-derived plastics, is 2,5-furandicarboxylic acid (FDCA). FDCA is a chemical derived from biomass that has low solubility in traditionally used solvents such as water. Thus, identifying solvents that can solubilize significant amounts of FDCA could allow for lower PEF production costs. In this study, FDCA solubility was investigated in nine pure solvents including H2O, acetonitrile (ACN), γ-valerolactone (GVL), γ-butyrolactone (GBL), ethanol (EtOH), methanol (MeOH), dimethyl sulfoxide (DMSO), sulfolane (SULF), and tetrahydrofuran (THF), eight binary, and three ternary solvent blends at 293 K. For all binary systems excluding DMSO and MeOH, the solubility of FDCA increased 1.5–65 times compared to the pure organic solvent, and the FDCA solubility was at least 10 times higher when compared to pure water. Specifically, the 20/80 w/w H2O/DMSO system solubilized 23.1 wt % FDCA, the highest of any binary blend studied, and 190 times more solubility than in pure water. In 20/80 w/w H2O/THF, the FDCA solubility was 60 times higher than pure water. In ternary blends that included DMSO, H2O, and either GVL, THF, or SULF, solubility increased by at least 6.6 times relative to the pure secondary organic component and 54 times relative to pure water. Using Hansen solubility parameters (HSPs), the radius of interaction (Ri, j) was found to be more strongly correlated to FDCA solubility than individual HSPs or the total solubility parameter. A MATLAB-based optimization code was developed and successful in minimizing the Ri, j of a solvent blend to maximize FDCA solubility in binary and ternary aqueous solvents.
Technical Writing and Simple Statistics: for laboratory classes
(Montana State University, 2022-11) Wettstein, Stephanie G.
This upper division resource focuses on how to communicate results through technical writing, use Excel to perform simple statistics, and create professional charts/documents. Excel tutorials are provided for performing descriptive statistics, t-tests, and linear regression as well as using text boxes, formatting figures and captions, and using Equation Editor to insert equations. Additionally, guidance and examples of different communication components are provided along with team writing strategies and guidelines on how to hold efficient meetings.