New quinone-based pulping catalysts

2,617-Dimethylanthraquinone (or DiMAO) and its precursor, octahydro-DiMAQ ( or ODiMAQ), have been synthesized from benzoquinone in high yield and at po tentially low cost. Both catalysts were twice as active as anthraquinone in soda, kraft, and polysulfide pulping systems. Pulps produced using these c atalysts were as easy to bleach as the corresponding AQ pulps and had the s ame strength properties. Analysis of unbleached pulps indicated that ODiMAQ was converted to DiMAQ during pulping and that there was approximately fou r times as much DiMAQ in these cooks as there was residual anthraquinone in the AQ cooks. Consequently, the end-of-cook concentration of DiMAQ may be higher than that of anthraquinone.