Mechanism of Humins Formation during Catalytic Conversion of Cellulose-Derived Carbohydrates

Friday, April 20, 2012
11:00 am – 12:00 pm
Room 610, M&M Building
Carl R. F. Lund
Dept. of Chemical and Biological Engineering
University at Buffalo, Buffalo, NY

John & Virginia Towers Distinguished Lecture Series


Cellulosic biomass represents a potential resource for sustainable production of fuels and chemicals. When cellulose is hydrolyzed using mineral acids as catalysts, dark-colored, tarry solids known as humins form as undesirable by-products. The formation and growth of humins have been investigated using small batch reactors, and the resulting humins have been characterized, primarily using scanning electron microscopy and infrared spectroscopy. The aqueous phase free energies of proposed reaction intermediates have been computed using quantum chemistry. The experimental and computational results are consistent with a sequential pathway for the formation of humins. The primary reaction proceeds through the sequential conversions of cellulose to glucose (perhaps) to fructose to HMF to levulinic acid. The predominant pathway for the formation of humins involves the conversion to HMF to 2,5-dioxo- 6-hydroxyhexanal (DHH). DHH rapidly undergoes aldol addition/condensation with available aldehydes or ketones. The resulting adduct then polymerizes to form humins. The experimental studies have shown that humin morphology, size and size distribution are affected by solvent choice. It has also been established that chemical functional groups can be added to the humins during or after their formation. These finding might lead to ways to convert humins from a waste byproduct to a more valuable commodity.

Bio: Dr. Lund is a SUNY Distinguished Professor. He was a department chair from 1997 to 2006. He obtained his B. S. from Purdue University in 1976 and Ph. D. from University of Wisconsin–Madison in 1981. His research interests include heterogeneous catalysis for energy and environmental applications, reaction engineering of membrane reactors, and biomass conversion. He received many awards, including NSF Presidential Young Investigator, SUNY Chancellor’s Award for Excellence in Teaching, and Lilly Teaching Fellow. He published more than 70 peer-reviewed papers.