Date of Award
Spring 4-6-2026
Document Type
Distinction Project
Degree Name
Chemistry-BS
Department
Chemistry
Advisor
Dr. Carrigan Hayes
First Committee Member
Dr. Carrigan Hayes
Second Committee Member
Dr. Dean Johnston
Third Committee Member
Dr. Grace Eder
Keywords
Chemistry, Computational Chemistry, Biofuels, Lignocellulosic Biofuels, Model Compound
Subject Categories
Higher Education
Abstract
Second-generation biofuels are those that can be generated from lignocellulosic materials and other non-food sources; they do not detract from the food chain as first-generation biofuels do. Second-generation biofuels have unique characteristics compared to other fuels, such as containing cyclic units and various heteroatoms, which can have energetic effects on combustion and need to be investigated. However, lignocellulosic species are not themselves feasible targets for a computational study because of their size and complexity. Rather, smaller model compounds are used to understand the behaviors of these larger systems. Previous research in our group has used composite computational methods (G3MP2B3) to model the carbon-hydrogen bond dissociation enthalpies (BDEs) of monocyclic oxygenates and their derivatives, exploring their promise as model compounds for larger systems. This study builds on our previous work: first seeking to replicate qualitative trends seen via composite calculations in alkylated monocyclic oxygenates via density functional theory (DFT); then confirming that these previously used models can be used with DFT to represent larger multicycles. With our method and our models validated, we used these models to expediently investigate the thermodynamic effects of heteroatoms and conformer effects during decomposition. Using Spartan ‘20 and Spartan ‘24 (Wavefunction, Inc.),18 carbon-hydrogen and carbon-carbon bond dissociation enthalpies (ΔH298, kJ/mol) were calculated (ωB97x-D/6-31G*) for alkyl-substituted derivatives of a variety of monocyclic and bicyclic compounds, including those derived from tetrahydropyran and morpholine. Boltzmann weights were calculated using Spartan Student using conformer distribution calculation. Qualitative trends in reactivity seen for substituted tetrahydropyran derivatives were consistent with earlier composite calculations, thus confirming our DFT method. In terms of the larger set of model compounds of interest, heteroatom presence had an effect on BDE, and trends in initial reactivity followed expected trends in radical stability. Cyclic conformer effects followed expected trends heavily favoring the equatorial conformer with small exceptions that should be considered in future work. Preliminary kinetic investigation of these models is underway, exploring activation barriers of these models with known decomposition reactions and exploring activity of peroxy radicals to simulate low-temperature combustion reactions of second-generation biofuels.
Licensing Permission
Copyright, all rights reserved. Fair Use
Acknowledgement 1
1
Acknowledgement 2
1
Recommended Citation
Scott, Paul A. III and Hayes, Carrigan, "Computational Exploration of Monocyclic Compounds for Lignocellulosic Biofuels" (2026). Undergraduate Distinction Papers. 130.
https://digitalcommons.otterbein.edu/stu_dist/130