Ragauskas Overview of Hexenurinic Acids on Pulp Bleaching Influence of Hexenuronic Acids on Kraft Bleaching

Over the past ten years there has been a research renaissance in hemicellulose chemistry as it applies to pulping and bleaching operations. Researchers have identified hemicelluloses as an important component influencing pulp yields, strength properties, and pulp bleachability. This report summarizes the research activities undertaken at IPST in the dues funded research consortium (DFRC) project F015 directed at evaluating the role of hemicelluloses in pulp bleachability. Currently, the focus of our studies is directed towards evaluating the impact that hexenuronic acids (HexA) have on chemical pulp production. These unsaturated sugars are formed by base catalyzed elimination of methanol from 4-O-methyl-D-glucurnoxylans during pulping, as shown in Figure 1.1. Clayton, Johansson and Samuelson, and Simkovi et. al established the fundamental chemical pathways involved in alkaline degradation of 4-O-methylglucuronoxylan.