Midinfrared FT-IR as a Tool for Monitoring Herbaceous Biomass Composition and Its Conversion to Furfural

Asemiquantitative analysis by means of midinfrared FT-IR spectroscopy was tuned for the simultaneous determination of cellulose,hemicellulose, and lignin in industrial crops such as giant reed (Arundo donax L.) and switchgrass (Panicum virgatum L.). Ternarymixtures of pure cellulose, hemicellulose, and lignin were prepared and a direct correlation area/concentration was achieved forcellulose and lignin, whereas indirect correlations were found for hemicellulose quantification. Good correspondences between thevalues derived from our model and those reported in the literature or obtained according to the official Van Soest method wereascertained. Average contents of 40–45% of cellulose, 20–25% of hemicellulose, and 20–25% of lignin were obtained for differentsamples of giant reed species. In the case of switchgrass, a content of 36% of cellulose, 28% of hemicellulose, and 26% of lignin wasachieved. This analysis was also carried out on giant reed and switchgrass residues after a mild hydrolysis step carried out with dilutehydrochloric acid for the production of furfural with good yield. Reasonable compositional data were obtained, thus allowing anindirect monitoring which helps the optimization of the hydrothermal pretreatment for furfural production from hemicellulosefractions.