Effect of maleic acid on the selectivity of glucose and fructose dehydration and degradation

<p>5-Hydroxymethyfurfural (HMF), a platform chemical can upgrade to a variety of fuels and polymers, can be manufactured from lignocellulose. This study focuses on the Lewis and Brønsted acid effect on hexose dehydration for HMF production. We report the positive effect of maleic acid, a dicarboxylic acid used as Brønsted acid, on the selectivity of hexose dehydration to 5-hydroxymethyfurfural (HMF), and subsequent hydrolysis to levulinic and formic acids. We also describe the kinetic analysis of a Lewis acid (AlCl₃) alone and in combination with HCl or maleic acid to catalyze the isomerization of glucose to fructose, dehydration of fructose to HMF, hydration of HMF to levulinic and formic acids, and degradation of these compounds to humins. Results show that AlCl₃ significantly enhances the rate of glucose conversion to HMF and levulinic acid in the presence of both maleic acid and HCl. In addition, the degradation of HMF to humins, rather than levulinic and formic acids, is reduced by 50% in the presence of maleic acid and AlCl₃ compared to hydrochloric acid combined with AlCl₃. The results suggest a different reaction mechanism for the dehydration of glucose and rehydration of HMF between maleic acid and HCl.^ Further elevated temperature (140-180 °C) experiment demonstrate the maleic acid alone behaves like Lewis acid to isomerization glucose to fructose. Maleic acid also found facilitating glucose ring open reaction. Compared to HCl combined with AlCl₃, calculated activation energy justifies maleic acid can lower the isomerization step activation energy when combined with AlCl₃.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Agricultural and Biological Engineering

Year

2015

Author dc:creator

• Zhang, Ximing

Contributors dc:contributor

• Nathan S. Mosier
• Michael R. Ladisch
• Abigail Engelberth
• Mahdi M. Abu-Omar

• Bioresource and Agricultural Engineering
• Chemical Engineering
• Chemistry

Repository record dc:identifier

https://docs.lib.purdue.edu/open_access_dissertations/609

OAI identifier oai:identifier

oai:docs.lib.purdue.edu:open_access_dissertations-1604