Influence of Quinones on the Estimation of Residual Lignin of Chlorine Dioxide Delignified Pulps by the Kappa Number Test, 2000 Pulping / Process & Product Quality Conference Proceedings
B. N. Brogdon--Chlorine dioxide delignification (D0) of kraft pulps caused the lignin/kappa number ratio to increase from 0.15 to 0.18. It was speculated that oxidized structures in the D0 residual lignin, such as quinones, consumed less perman-ganate than unbleached residual lignin. Kraft pulps oxidized with periodate, a method known to produce quinone structures, also showed an increase in the lignin/kappa ratio from 0.15 to 0.18. Results from model compound stud-ies indicated that quinones consumed ~25 to 40% less permanganate than corresponding phenolic or dihydroxyben-zene models. Hydrosulfite reductions of periodate and D0 pulps caused the lignin/kappa ratio to return to 0.15. Based on these findings, it was estimated that the D0 residual lignin contained ~35 quinones per 100 phenylpropane units.
Influence of Quinones on the Estimation of Residual Lignin of Chlorine Dioxide Delignified Pulps by
