Lignocellulose consists of lignin, cellulose (a polymer of b-1,4-linked glucose molecules) and hemicellulose (a polymer of different 5 and 6 carbon sugars). It is the main constituent of plant cell walls. As a biopolymer of high abundance, lignin has significant potential as a sustainable feedstock of aromatic chemicals. While fine structural details are variable, lignin is composed of the three basic monomers shown below. Despite the commercial value of these aromatic components, lignin is usually burned rather than strategically degraded following the commercial separation of cellulose from lignocellulose. This is because of an unintentional consequence of current methods to isolate cellulose which result in new C–C bonds that further cross-link or “condense” the lignin structure, making isolation of its monomeric degradation products prohibitively difficult. Much interest remains in developing methods to separate cellulose from hemicellulose that avoid lignin condensation. We have recently elucidated a new method of separating polysaccharides from extractive-free pine sawdust using an equimolar ratio of BBr3 and BCl3 at room temperature. The efficiency of this separation was analyzed by solid state NMR and by staining with fluorescent and colorimetric dyes which are selective for polysaccharide components. In particular, fluorescent staining indicated a complete absence of cellulose/hemicellulose from the boron trihalide treated sawdust samples. Work is now focused on characterizing the remaining lignin and quantifying the extent of condensation as a result of boron trihalide treatment.

Separation of cellulose/hemicellulose from lignocellulose in white pine sawdust using boron trihalide reagents

ACS Fall 2020 Virtual Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.