• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.5
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• pp.7-11
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• 2007

Kraft pulping of Trema orientalis (Nalita) was studied in order to find kinetic data for delignification. Pulping runs were carried out in the temperature range of $160-180\;^{\circ}C$ under constant and well-defined conditions. The delignification was found to be first order with respect to residual lignin and was chemically controlled. The rate of delignification reaction was increased 1.11-1.23 for $10\;^{\circ}C$ temperature increase in the range of $160-180\;^{\circ}C$ range. A mean value of 93% of lignin was removed at the transition between bulk and residual delignification. The influence of cooking temperature on the rate constant was expressed by an Arrhenius-type equation. The obtained activation energy of the delignification reaction was 6,164 cal/mol. The transition point between bulk and residual phase was shifted to lower lignin and carbohydrate yield with the increase of temperature.

• Journal of Korean Society of Forest Science
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• v.56 no.1
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• pp.26-50
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• 1982

In order to obtain more detailed information concerning the degradation of lignin in the oxygen alkali pulping single stage isothermal delignification of pine wood meal (Pinus koraiensis S. et Z.) was studied in the oxygen alkali system at five temperature level ($110^{\circ}C$, $120^{\circ}C$, $130^{\circ}C$, $140^{\circ}C$, $150^{\circ}C$) for 60 min.. The rate constant, activation energy, oxygen and alkali consumption during the oxygen alkali delignification were determined by the kinetic method. The 2/5 of total lignin was eliminated at the start of the reaction. The delignification rate constant was about 3 times that of caustic soda pulping. The activation energy was about 1/3 lower than in caustic soda pulping. Like oxygen consumption, alkali consumption was also rapid early at the reaction and almost ceased after about 10 min.. The degradation reaction of lignin was strongly dependent upon the pH decrease of the cooking liquor by organic acid generated in pulping. The lignin in the oxygen alkali pulping degraded into lover molecular weight and had more hydrophillic properties. The methoxyl group decreased considerably at the first of oxygen alkali delignification, while the carbonyl, carboxyl and phenolic hydroxyl group increased rapidly.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.353-353
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• 2006