A Comparison of Dilute Aqueous Isethionic Acid and Sulfuric Acid in Hydrolysis of Three Different Untreated Lignocellulosic Biomass Varieties

Efficient catalytic hydrolysis of lignocellulosic biomass to sugars is a major challenge in the production of sustainable biofuels and chemical feedstocks. In this study isethionic acid was compared with H2SO4 for hydrolysis of polysaccharides in corn stover, switch grass, and poplar. The catalytic activities of acids were compared by analysis of total reducing sugar (TRS) and glucose yields in a sequence of experiments in water at 90-190 degrees C using 0.050 mol of H+/L isethionic acid and H2SO4. In comparison to using H2SO4, the use of isethionic acid catalyst lowered the maximum TRS percent yield temperatures by 25, 24, and 21% for corn stover, switch grass, and poplar. A similar effect was observed for glucose percent yields as well. This temperature reduction is due to lowering of the activation energy in the polysaccharide depolymerization reaction and most likely due to hydrogen-bonding-type dipolar interactions between the isethionic acid -OH group and -OH groups in biomass polysaccharides.

Automated summary

Efficient catalytic hydrolysis of lignocellulosic biomass to sugars is a major challenge in sustainable biofuel and chemical feedstock production. This study compared the effectiveness of isethionic acid and sulfuric acid catalysts in the hydrolysis of polysaccharides in corn stover, switch grass, and poplar. It was found that the use of isethionic acid catalyst reduced the optimal reaction temperature and increased sugar yields, potentially due to hydrogen-bonding-type dipolar interactions between isethionic acid and biomass polysaccharides.