Date Available

12-22-2022

Year of Publication

2022

Degree Name

Master of Science (MS)

Document Type

Master's Thesis

College

Engineering

Department/School/Program

Biosystems and Agricultural Engineering

First Advisor

Dr. Czarena L. Crofcheck

Second Advisor

Dr. Eduardo Santillan-Jimenez

Abstract

While lignin has been regarded as the most promising renewable feedstock for the sustainable manufacture of aromatic compounds, lignin valorization is necessary to improve the economic viability of biorefineries. Reductive catalytic fractionation (RCF), which combines delignification and lignin depolymerization into a single stage while maintaining the structure and integrity of the cellulose component, has evolved as an effective method for processing biomass. The ability of Cu and Fe to promote the performance of a 20% Ni/alumina catalyst when converting native lignin to alkylphenols by RCF in sub- and supercritical methanol was tested. The effectiveness of lignin extraction as measured by lignin oil production, the quantity and distribution of identifiable monomers in lignin oil, and the yield of residual solids were examined. All Ni-based catalysts tested performed similarly in terms of product distribution and monomer yields, offering improved yields of lignin oil and detectable monomers along with reduced char formation in conditions relative to blank (sans catalyst) runs. Ni-Cu catalyst in the presence of supercritical methanol, with a monomer yield of 51%, performed better than Ni-Fe and Ni-only formulations. Several catalyst characterization methods were employed to identify the structure-activity relationships underpinning the performance of these catalysts in lignin valorization.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2022.454

Funding Information

This study was supported by the National Science Foundation Bridge to Doctorate Fellowship (no.: HRD 2004210) and the National Science Foundation Graduate Research Traineeship grant (no.: 1922694)

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