• Journal of the Korean Wood Science and Technology
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• v.18 no.4
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• pp.18-25
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• 1990

As polysaccharides in lignocellulosic materials are encrusted with aromatic lignin molecules and have high crystallinity, these require pretreatment to improve their digestability by cellulolytic enzymes. Though a number of pretreatment methods have been proposed, the steam explosion process is evaluated as a promising method. This study was performed to investigate the effect of delignification treatment by alkali, methanol and the others on the enzymatic hydrolysis. Delignification treatment resulted in great increase rate in enzymatic hydrolysis. Concerning to the effect of delignication reagents on the enzymatic hydrolysis, methanol treatment was more effective than alkali in the case of oak wood. In pine wood, the delignification did not showed any significant enhancement of hydrolysis rate. Complete delignification by Alkali-Oxygen. Alkali treatment showed high saccharification rate of 99.5%.

• Journal of the Korean Wood Science and Technology
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• v.22 no.1
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• pp.34-39
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• 1994

Effects of Mg-base acid sulfite and Mg- or Na-base bisulfite on pine bark cooking were examined. In the presence of 75 % free acid at 145 $^{\circ}C$, the rate of cooking and delignification was improved with the increase of total acid. However, the delignification could not be achieved by 50 % or more under these cooking conditions. When cooked with 50~65 % free acid and at 155~165 $^{\circ}C$, the rate of cooking and delignification was remarkably improved. Thus, the bark was delignified up to 73 % when cooked for 2 hours in the presence of 50 % free acid and 24 % total acid. Na-base bisulfite was slightly more effective than Mg-base bisulfite for cooking, giving 76 % delignification of pine bark. However, there was no significant difference in selectivity of delignification between Na- and Mg-base bisulfite cooking.

• 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 the Korean Wood Science and Technology
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• v.20 no.3
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• pp.11-20
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• 1992

Steam explosion is one of the most effective pretreatment for fractionating wood. This leads to the total utilization of wood basic components; cellulose, hemicellulose and lignin. The amount of sugar and lignin extracted with the hot water method was very low. The lignin content of residues after extraction with using a sodium hydroxide treatment, increased delignification of carbohydrate as the concentration of alkali was increased. Oak, pretreated with steam exploded at 25kg/$cm^2$ for 6 min. then 1% alkali for 2hrs. showed a delignification rate up to 95%. A sodium chlorite treatment of steam exploded pine and oak also afforded a high deligninfication effect. Pine, treated 10% sodium chlorite for 2hrs. showed high delignification. However, by using a sodium hydroxide treatment, a 2% retreatment for Ihr. after a 2% for 2hrs. afforded remarkable delignification effect on exploded wood at 30kg/$cm^2$ for 9min. and at 35kg/$cm^2$ for 3-6min. In oak, an initial 2hrs. treatment of 2% sodium chlorite was followed by a second 2hrs. treatment at 10%. This showed a delignification rate of 96%.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.46-52
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• 1999

Alkaline sulfite-anthraquinone(AQ) cooking was examined for their effectiveness in delignification of pine (Pinus densiflora S. et Z.) bark. Better delignification was achieved with alkaline sulfite liquor compared to monosulfite liquor, but the degree of delignification was less than 90% indicating need for improvement in cooking method, Remarkable increase in the rate of cooking and delignification was obtained by the simple addition of AQ to the alkaline sulfite cooking, Selectivity of delignification was also improved by the addition of AQ, Consequently, 90% of delignification was achieved with the addition of 0.2% AQ to the alkaline sulfite cooking. The selectivity of delignification was slightly affected by cooking temperature and NaOH concentration during alkaline sulfite-AQ cooking of the bark. The selectivity of delignification was highly affected by the concentration of $Na_2SO_3$, and the optimum concentration of $Na_2SO_3$ for the high delignification was 30% as $Na_2O$.

• Journal of the Korean Wood Science and Technology
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• v.20 no.1
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• pp.60-71
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• 1992

To investigate the delignification behaviour in solvolysis pulping process, Populus alba ${\times}$ glandulosa H. and Pinus Kuraiensis S. et Z. were cooked with p-cresol and vater solvent(2:8, 5:5, 8:2 v/v) at $175^{\circ}C$ for 9 cooking time levels(20, 40, 60, 80, 100, 120, 140, 160, 180, min). Pulp yield, residual lignin content, de lignification rate, decarborhydration rate were determined. Delignification behaviours were analyzed by TEM. 1. The p-cresol-water solvent cooking of P. alba ${\times}$ glandulosa showed good delignification at the solvent system which the mixture ratio of p-cresol and water were 2:8(v/v), while the cooking of P. koraiensis with the p-cresol and water mixture ratio of 5:5 was no good. 2. P. alba ${\times}$ glandulosa showed three step-delignification phenomena at the solvent system which the mixture ratio of p-cresol and water were 2:8(v/v) anti 5:5(v/v). But P. koraiensis showed a first order delignification reaction at the same mixture ratio of p-cresol and water solvent system. 3. In TEM micrograph obtained for the solvent system which the mixture ratio of p-cresol and water was 5:5(v/v), the partial delignification of the cell corner of P. alba ${\times}$ glandulosa and P. koraiensis were observed at 60min. of cooking time. Complete delignification at the cell corner of P. alba ${\times}$ glandulosa was observed at 160min. and that of P. koraiensis was observed of 180min. of cooking time. 4. In optical microscopic observation, fiber separation of P. alba ${\times}$ glandulosa occured at 120min. and that of P. koraiensis began at 140min. of cooking time. 5. At the solvent system which the mixture ratio of p-cresol and water was 5:5(v/v), middle layer on secondary wall($S_2$) and cell corner of P. alba ${\times}$ glandulosa were more selectively delignified than primary wall(P) and outer layer on secondary wall($S_1$). However P. koraiensis did not showed any difference in delignification between cell wall layers and cell corner.

• Journal of the Korean Wood Science and Technology
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• v.22 no.1
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• pp.28-33
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• 1994

The chemical compositions of pine bark from mechanical pulp industry were determined, and effect of Ca base acid sulfite on bark cooking was investigated under various conditions. The pine bark was composed of 39.5 % alkali extractives, 50.3 % lignin, and a small amount of carbohydrate. The contents of alkali extractives and lignin were remarkably higher than those of pine wood. The bark was composed of high content of arabinose and xylose, while the wood was composed of high content of mannose. When pine bark was cooked with 75 % free acid at 145 $^{\circ}C$, the rate of cooking and delignification was improved with the increase of total acid, but it was very difficult to delignify the bark by 50 % and over under these conditions. In the presence of 60~65 % free acid and at 155~165 $^{\circ}C$, initial cooking rate, delignification, and delignification selectivity were considerably increased, but condensation reaction of lignin was considerable at the end of cooking. Therefore, it was shown that pine bark was very difficult to delignify by the Ca-base acid sulfite cooking.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.4
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• pp.21-29
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• 2015

In this study, the feasibility of utilizing wood chips from pitch pine (Pinus rigida) was evaluated for bioethanol production by an organosolv pretreatment and enzymatic saccharification. When wood chips from pitch wood were pretreated with 75% (v/v) ethanol and 1.7% sulfuric acid as a catalyst at H-factor 2000, average pulp yield was 43.3%, which pretreated wood fibers showed higher glucan (55.8%) and lower lignin (12.2%) contents than untreated control (43.9% glucan and 27.8% lignin). After enzymatic saccharification, the organosolv pulps with 56.2% delignification rate reached above 97% conversion rate of cellulose to glucose. These results indicated that increasing the delignification rate causes micro pores on the surface of organosolv pulps resulting in improved the accessibility of enzyme onto the substrate. Moreover, it was in agreement with the SEM examination of wood fibers.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.285-290
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• 2006

As an alternative method to solve air pollution problem and difficulty of pulp bleaching of kraft pulping process, NaOH-Urea pulping was applied. The properties of NaOH-Urea pulp were compared to those of NaOH and kraft pulps. Addition of urea in low alkali charges retarded delignification rate compared to NaOH pulping. But, in high alkali application, delignification was significantly enhanced not from the addition of urea but from the high alkalinity. It was disclosed that urea did not participate on delignification reaction by the experiment using lignin model compound. Compared to paper strengths at the same level of sheet density, NaOH-Urea pulp gave as almost same breaking length and tensile index as those of kraft pulp. Especially tensile energy absorption and burst index were higher than those of kraft pulp.

• 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.