Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
권호 표지

Chemical Features of Solid Residues Obtained from Supercritical Water Treatment of Populus alba×glandulosa

현사시나무 목분의 초임계수 처리 공정으로부터 유래한 미분해 고형성분의 화학적 특성

  • Kim, Kwang Ho (Dept. Forest Sciences, CALS, Seoul National University) ;
  • Eom, In Yong (Dept. Forest Sciences, CALS, Seoul National University) ;
  • Lee, Soo Min (Div. Wood Chemistry & Microbiology, Korea Forest Research Institute) ;
  • Lee, Oh Kyu (Div. Wood Chemistry & Microbiology, Korea Forest Research Institute) ;
  • Meier, D. (Institute of wood chemistry and chemical technology of wood, Federal research center for forestry and forest products (BFH)) ;
  • Choi, Joon-Weon (Dept. Forest Sciences, CALS, Seoul National University)
  • 김광호 (서울대학교 농업생명과학대학 산림과학부) ;
  • 엄인용 (서울대학교 농업생명과학대학 산림과학부) ;
  • 이수민 (국립산림과학원 화학미생물과) ;
  • 이오규 (국립산림과학원 화학미생물과) ;
  • ;
  • 최준원 (서울대학교 농업생명과학대학 산림과학부)
  • Received : 2009.01.12
  • Accepted : 2009.03.25
  • Published : 2009.07.25
Download PDF
⟨ Previous Next ⟩

Abstract

After supercritical water treatment of poplar wood meals (passed through 60 mesh) for 60s between 325 and $425^{\circ}C$ at the fixed pressure at $220{\pm}10atm$, some solid residues were present in the degradation products. They mainly consisted of chemically modified lignin and fibrous materials. Glucose and xylose were identified as main sugar components of fibrous materials, and the highest ratio of glucose/xylose was achieved at the highest reaction temperature. As reaction temperature was elevated, the portion of fibrous materials decreased in the solid residues, while lignin was further accumulated. The H : G : S ratio of lignin in solid residues was estimated by analytical pyrolysis. Irrespective of reaction temperatures, the H:G:S ratios were not significantly changed in the lignin in solid residues. Compared to poplar milled wood lignin (MWL), it was remarkable that H type monomers were further lowered, while portion of S type monomers increased. The amount of G type monomers were relative stable. In presence of HCl catalyst, lowering H type as well as enhancing S type was further distinguishable. According to the result of nitrobenzene oxidation (NBO), ca. 265 mg of vanillin and syringaldehyde was yielded from poplar MWL as main products. However, remarkably reduced amount of NBO products were determined from solid residues by raising operating temperature as well as by the addition of HCl catalyst. These results strongly indicate that $\beta$-O-4 linkage could be easily cleaved during supercritical water treatment, so that the lignins in the solid residues seem to be condensed phenol polymers, which are mainly formed by carbon-carbon linkages rather than $\beta$-O-4 linkage.

현사시나무 분말(60 mesh 통과)을 압력 $220{\pm}10atm$, 온도 $325{\sim}425^{\circ}C$ 범위 내에서 60초 간 초임계수로 처리한 후에 미분해 고형잔사를 얻을 수 있었다. 고형잔사 내 섬유상 물질을 구성하는 주요 당은 글루코오스와 자일로스였으며, 가장 높은 온도인 $425^{\circ}C$에서 초임계수 처리를 하였을 때 글루코오스/자일로스 구성 비율이 가장 높게 측정되었다. 초임계수 반응온도가 높아질수록 고형 잔사를 구성하는 섬유상 물질의 비율은 감소하였으나, 리그닌의 비율은 상대적으로 증가하였다. 고형잔사에 존재하는 리그닌의 H (p-hydroxyphenyl) : G (guaiacyl) : S (syringyl) 비율은 분석형 열분해법으로 측정하였으며, 반응온도에 따른 변화 없이 비교적 일정하게 나타났다. 고형잔사를 구성하는 리그닌의 H : G : S 조성을 현사시나무에서 단리한 milled wood lignin (MWL)과 비교해보면 G 형 단량체의 비율에는 큰 변화가 없었지만, H 형 단량체 비율은 비교적 낮게 측정되었고, 반면 S 형 단량체 비율은 증가하였다. 초임계수 당화과정에 염산촉매를 첨가하면 H 비율의 감소와 S 비율의 증가는 더욱 두드러지게 나타났다. 니트로벤젠 산화법(nitrobenzene oxidation)에 의하면 현사시나무 MWL에서 획득한 vanillin과 syringaldehyde의 수율은 약 265 mg/g MWL으로 측정되었지만, 초임계수 고형성분의 NBO 분석 결과에 의하면 반응온도를 높여 주거나 염산촉매를 첨가하면 NBO 분해산물은 두드러지게 감소하였다. 이러한 결과는 초임계수 반응 조건에서 리그닌의 주요 결합 양식인 $\beta$-O-4 결합이 비교적 쉽게 끊어지는 것으로 해석되며, 따라서 초임계수 반응 후 고형성분에 존재하는 리그닌은 $\beta$-O-4 결합 대신 탄소-탄소 결합에 의한 축합형 페놀고분자로 예측되었다.

Keywords

Acknowledgement

Supported by : 산림청

References

  1. 최준원, 임현진, 한규성, 최돈하. 2006. 초임계수에 의한 현사시나무의 당화 특성. 목재공학. 34(6): 44∼50
  2. 최준원, 임현진, 한규성, 강하영, 최돈하. 2005. 초임계수에 의한 현사시 목분의 분해특성 및 분해산물 분석. 임산에너지. 24(1): 39∼46
  3. Ehara, K. and S. Saka. 2002b. A Comparative Study on Chemical Conversion of Cellulose between the Batch-type and Flow-type Systems in Supercritical Water. Cellulose 9: 301∼311 https://doi.org/10.1023/A:1021192711007
  4. Ehara, K. and S. Saka. 2005 Decomposition Behavior of Cellulose in Supercritical Water, Subcritical Water, and their Combined Treatments. J. Wood Sci. 51: 148∼153 https://doi.org/10.1007/s10086-004-0626-2
  5. Ehara, K., S. Saka, and H. Kawamoto. 2002a. Characterization of the lignin derived products from wood as treated in supercritical water. J. Wood Sci. 48: 320∼325 https://doi.org/10.1007/BF00831354
  6. Iiyama, K. and T. B. T. Lam. 1990. Lignin in wheat nodes. Part I: The reactivities of lignin units during alkaline nitrobenzene oxidation. Journal of Sci. Food Agric. 51: 481∼491 https://doi.org/10.1002/jsfa.2740510405
  7. Faix, O., D. Meier, and I. Fortmann. 1990a. Thermal degradation products of wood. Gas chromatographic separation and mass spectrometric characterization of monomeric lignin derived products. Holz Roh- Werkstoff. 48: 281∼285 https://doi.org/10.1007/BF02613278
  8. Faix, O., D. Meier, and I. Fortmann. 1990b. Thermal degradation products of wood. A collection of electron-impact (EI) mass spectra of monomeric lignin derived products. Holz Roh- u. Werkstoff. 48: 351∼354 https://doi.org/10.1007/BF02639897
  9. Meier, D. and O. Faix. 1992. Pyrolysis-gas chromatography-mass spectrometry. In: S. Y. Lin and C.. Dence (Eds.) Methods of Lignin Chemistry. Springer, Berlin. 177199
  10. Moiser, N., C. Wyman, B. Dale, R. Elander, Y. Y. Lee, M. Holtzapple, and M. Ladisch. 2005. Features of promising technologies for pretreatment of lignocellulosic biomass. Bioresource Technology. 96. 2005 https://doi.org/10.1016/j.biortech.2004.06.025
  11. Vieb$\ddot{o}$ck, F. and A. Schwappach. 1930. Eine neue Methode zur naßanalytischen Bestimmung der Methoxyl- und $\ddot{A}$thoxylgruppe. Chem. Ber. 63:2818∼2823
  12. Wyman, C. E., B. E. Dale, R. T. Elander, M. Holtzapple, M. R. Ladisch, and Y. Y. Lee. 2005. Coordinated development of leading biomass pretretment technologies. Bioresource Technology. 96: 1959∼1966 https://doi.org/10.1016/j.biortech.2005.01.010