A Comprehensive Look at the Acidic Hydrolysis of Loblolly Pine Sawdust

A comprehensive study of the acid hydrolysis of Loblolly pine, using different hydrolysis conditions is presented. The effect of the type of acid, pH, reaction temperature, and reaction time on hydrolysis products such as monosaccharides and the subsequent degradation products, HMF and furfural, is reported using a stirred batch reactor. Trifluoroacetic acid is found to yield the highest amount of overall soluble monosaccharides mainly from hemicelluloses. The mineral acids (HCl, H2SO4, HNO3, H3PO4) gave a slightly lower yield of monosaccharides from hydrolyzed hemicellulose because monosaccharides are faster degraded. At 200°C, substantial amount of cellulose is hydrolyzed by mineral acids. Larger amounts of degradation products are also noted at higher temperatures. TFA was found to be the most “gentle” acid, leading to limited monosaccharide degradation among the acids used. The presence of soluble oligosaccharides in solution after hydrolysis was confirmed by applying a secondary acid hydrolysis to the solid-free liquid hydrolysate.