Pulping Catalysts from Lignin — The Diels-Alder Step

Certain anthraquinone (AQ) compounds can be used in existing kraft processes to increase pulping rates and pulp yields. Such catalysts could also be the focus for an industry-wide evolution of pulping from high to low to sulfur-free methodology. Catalytic pulping holds the promise of addressing problems with plant bleach effluents by producing pulps that are more easily bleached than standard kraft pulps by modifying the cooking process to reduce the amount of residual lignin present in the pulp prior to bleaching.1