ABSTRACTS

Journal

  1. Structural analysis of alkaline cooked lignin by pyrolysis-gas chromatography. Evaluation of uniformity in delignification of beech wood chips

  2. Kami Pa Gikyoushi, 48 (9), 1212-1220 (1994)
  3. Structural Analysis of Lignin by Pyrolysis-Gas Chromatography II. Analysis of decayed wood lignin

  4. Kami Pa Gikyoushi, 49 (4), 735-745 (1995)
  5. Structural Analysis of Lignin by Pyrolysis-Gas Chromatography IV. Comparison with nitrobenzene oxidation for determination of decayed hardwoods and kraft-cooked hardwoods

  6. Kami Pa Gikyoushi, 51 (2), 358-366 (1997)
  7. Structural Analysis of Lignin by Pyrolysis-Gas Chromatography V. Analysis of lignin in mechanical pulp and paper

  8. Kami Pa Gikyoushi, 51 (6), 932-944 (1997)
  9. 5-Hydroxyguaiacyl nuclei as an aromatic constituent of native lignin

  10. Phytochemistry, 46 (4), 695-700 (1997)
  11. Structural characteristics of lignin and wall polysacchaides in steam exploded pulps of oil palm (Elaeis guneensis Jaxq.) frond relating to self-binding mechanism of binderless boards prepared from them.

  12. Holzforshung, 52 (4), 417-426 (1998)
  13. Compositional and structural characteristics of residual biomass from tropical plantations

  14. Journal of Wood Science, 44 (1), 40-46 (1998)

Symposium

  1. Structural analysis of alkaline cooked lignin by pyrolysis-gas chromatography evaluation of uniformity in delignification of beech wood chips.
    International symposium on Fiber science and Technology, Yokohama, Japan, (1994)
  2. Analysis of Lignin in Various Kinds of Paper by Pyrolysis-Gas Chromatography

  3. The Proceedings of 1995 (62nd) Pulp and Paper Research Conference, Tokyo, June 2, p.86-91 (1995)
  4. Analysis of Lignin in Thermomechanical Pulp by Pyrolysis-Gas Chromatography

  5. International Symposium of Cellulose and Lignocellilosis '96, Guangzho, China, June 6-8, p.177-178 (1996)
  6. Preparation of Binderless Boards from Steam Exploded Pulp of Oil Palm Frond and Structural Characteristic of Lignin in Steam Exploded Pulp

  7. Proceedings of The 41st Lignin Symposium , Nagoya Japan, Oct. 3-4, p.73-76 (1996)
  8. 5-Hydroxyguaiacyl Nuclei in Native Lignin

  9. Proceedings of The 41st Lignin Symposium , Nagoya Japan, Oct. 3-4, p.37-40 (1996)
  10. Pyrolysis-Gas Chromatographic Analysis of Ferulic acid Generated in Softwood Thermomechanical Pulps during Light Irradiation

  11. 9th International Symposium on Wood and Pulping chemistry Poster Presentations , Montréal, Canda, June 9-12, p.110-1-110-4 (1997)
  12. Preparation of binderless boards from steam exploded pulp of oil palm frond

  13. 9th International Symposium on Wood and Pulping chemistry Oral Presentations , Montréal, Canda, June 9-12 p.I1-1-I1-4 (1997)

Structural analysis of alkaline cooked lignin by pyrolysis-gas chromatography

Evaluation of uniformity in delignification of beech wood chips

Satoshi Suzuki, Akiko Izumi, Hiroshi Ohi , Ken-ichi Kuroda and Akira Yamaguchi

* Institute of Agricultural and Forest Engineering, The University of Tsukuba, Tsukuba, Ibaraki 305, Japan
Ununiformity in delignification of beech wood chips was studied by using pyrolysis-gas chromatography (Py-GC).

Ten compounds (guaiacol, 4-methylguaiacol, 4-vinylguaiacol, vanillin, trans-isoeugenol, syringol, 4-methylsyringol, 4-vinylsyringol, syringaldehyde and trans-4-propenylsyringol) were identified in pyrolysis products of kraft and soda-THAQ (1,4,4a,9a-tetrahydroanthraquinone) pulps. A high correlation between the ratios of syringyl derivatives to guaiacyl derivatives (S/G) and the amounts of Klason lignin was found. Measuring S/G enabled to estimate the Klason lignin contents of beech pulps. Ununiformity in delignification of beech wood chips after kraft cooking could be evaluated by measuring S/G of slices of the chip. As the delignification during alkaline cooking proceeded, relative yields of guaiacol and syringol to those of the other pyrolysis products from residual lignin in pulps increased.

To clarify the lignin structure which gave guaiacol and syringol in Py-GC, lignin model compounds (syringylglycol- beta -guaiacylether, syringaresinol) were analyzed. Although guaiacol was formed from syringylglycol-beta-guaiacylether, syringol was not formed under the present conditions. On the other hand, syringaresinol gave syringol. These results suggested that the beta -O-4 bond of lignin could be cleaved, and that the C-C bond between C alpha -OH and an aromatic nucleus with a free phenolic hydroxyl group could not be cleaved.

Py-GC was expected to be a promising method for characterization of residual lignin in alkali pulps.

Kami Pa Gikyoushi, 48 (9), 1212-1220 (1994)

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Structural Analysis of Lignin by Pyrolysis-Gas Chromatography II.

Analysis of decayed wood lignin

Satoshi Suzuki, Akiko Izumi, Hiroshi Ohi, Ken-ichi Kuroda and Akira Yamaguchi

Pyrolysis-gas chromatography (Py-GC) was applied to the characterization of lignin in decayed woods. Recently, Py-GC becomes one of the powerful tools for analyses of synthetic polymers. Very small amounts of solid materials are analyzed rapidly by using Py-GC. In the structural analysis of lignin in woods, lignin can be analyzed by Py-GC without being isolated from woods.

When sugi (Cryptomeria japonica) woods is analyzed by Py-GC, the eight main lignin-derived pyrolysis products (guaiacol, 4-methylguaiacol, 4-vinylguaiacol, vanillin, trans-isoeugenol, dihydroconiferyl alcohol, coniferaldehyde and trans-coniferyl alcohol) can be detected. Pyrolysis of woods decayed by Coriolus versicolor and Tyromyces palustris provided the eight pyrolysis products in a smaller yield than that of the sound wood.

In pyrolysis of sugi woods decayed by C. versicolor, the ratios of the peak area of guaiacol to the combined peak areas of the eight pyrolysis products (cpaG) increased with decreasing combined peak areas. On the other hand, in pyrolysis of sugi woods decayed by T. palustris, no clear relationship was found between the ratios of the peak area of pyrolysis products to cpaG and cpaG per sample weight.

Beech (Fagus crenata) woods were also decayed by C. versicolor, Daedalea dickinsii, Ganoderma lucidum and T. palustris , and analyzed by Py-GC. All decayed beech woods showed the smaller ratios of the combined peak areas of the four main syringyl type compounds (syringol, 4-methylsyringol, 4-vinylsyringol, trans-4-propenylsyringol) (sumS) to the combined peak areas of the four main guaiacyl type compounds (guaiacol, 4-methylguaiacol, 4-vinylguaiacol, trans-isoeugenol) (sumG) than that of sound wood. This suggests that syringyl units of lignin were preferentially degraded to guaiacyl units. The ratios of the peak area of guaiacol to sumG and the ratios of the peak area of syringol to sumS increased in pyrolysis of beech woods decayed by the above four fungi.

To clarify the convincing pyrolytic origins of the lignin structures giving syringol and guaiacol in high yields, some lignin dimer model compounds were subjected to Py-GC: syringylglycol- beta -guaiacyl ether (SG-OH), dehydrodiisoeugenol (DDI) and alpha -guaiacoxyacetosyringone (SG=O). A phenylcoumaran type lignin model compound, DDI, did not give guaiacol. Similarly syringol was not formed from SG-OH, which is the beta -O-4 analogue having a hydroxyl group at the C alpa -position. On the other hand, the beta -O-4 analogue having a carbonyl group at the C alpha -position, SG=O, gave syringol by the pyrolytic cleavage of the bond between the C atom and aromatic ring in a 3mol% yield. These findings suggest that the formation of alpha -carbonyl groups in the lignin macromolecule by fungal treatments should be one of the reasons why the ratios of guaiacol and syringol increased in Py-GC of the decayed woods. Py-GC is expected to be a promising method for characterization of the decayed wood lignin.

Kami Pa Gikyoushi, 49 (4), 735-745 (1995)

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Structural Analysis of Lignin by Pyrolysis-Gas Chromatography IV. Comparison with nitrobenzene oxidation for determination of decayed hardwoods and kraft-cooked hardwoods

Junji Tanaka, Akiko Izumi, Satoshi Suzuki, Hiroshi Ohi and Ken-ichi Kuroda

* Institute of Agricultural and Forest Engineering, The University of Tsukuba, Tsukuba, Ibaraki 305, Japan
In order to learn the effectiveness of pyrolysis-gas chromatography (Py-GC) on the characterization of chemically or biologically modified lignin, decayed hardwoods and kraft-cooked hardwoods were subjected to Py-GC as a tool for the convenience lignin analysis tool. The selected guaiacyl pyrolysis products (guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-vinylguaiacol, eugenol, vanillin, trans-isoeugenol and trans-coniferyl alcohol and their syringyl analogueisyringol, 4-methylsyringol, 4-ethylsyringol 4-vinylsyringol, 4-allylsyringol, syringaldehyde, trans-4-propenylsyringol and trans-sinapyl alcohol, as the main lignin-derived compounds, were determined using each absolute calibration factors to flame ionization detector. The results were compared with those by the alkaline nitrobenzene oxidation.

European beech (Fagus silvatica) woods were decayed by a brown-rot fungus (Tyromyces palustris) or a white-rot fungus (Coriolus versicolor), and beech (Fagus crenata) woods were cooked with kraft liquor. Residual lignin contents of wood samples were measured by the Klason lignin methods. Lignin was analyzed by Py-GC and the alkaline nitrobenzene oxidation method quantitatively without isolation from woods. The yields of the pyrolysis products were obtained on the basis of the residual lignin in decayed woods, and changes in the yields and their relative compositions during the decay for 180 days were investigated. The molar ratios of syringyl type pyrolysis products to guaiacyl ones (S/G ratios) measured by Py-GC were compared with the molar ratios of syringaldehyde to vanillin (S/V ratios) obtained by the nitrobenzene oxidation.

(1) In pyrolysis of 180 days-decayed woods by Tyromyces palustris , the yields of trans-coniferyl alcohol and trans-sinapyl alcohol sharply decreased.
(2) In those by Coriolus versicolor, the yields of trans-coniferyl alcohol and trans-sinapyl alcohol decreased, and relative compositions of guaiacol and syringol clearly increased.
(3) For decayed woods by Coriolus versicolor, the yields of syringyl type pyrolysis products decreased more rapidly than those of guaiacyl ones with increase of decaying days. The S/G ratios measured by Py-GC were in good agreement with the S/V ratios obtained by the nitrobenzene oxidation.
(4) In pyrolysis of kraft-cooked woods, the yields of trans-coniferyl alcohol and trans-sinapyl alcohol decreased, and relative compositions of guaiacol and syringol increased.
(5) The S/G ratios of residual lignin in kraft-cooked woods decreased with increase of cooking time, and those were in good agreement with the S/V ratios.

Kami Pa Gikyoushi, 51 (2), 358-366 (1997)

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Structural Analysis of Lignin by Pyrolysis-Gas Chromatography V. Analysis of lignin in mechanical pulp and paper

Satoshi Suzuki, Hiroshi Ohi, Ken-ichi Kuroda

* Institute of Agricultural and Forest Engineering, The University of Tsukuba, Tsukuba, Ibaraki 305, Japan
Pyrolysis-gas chromatography (Py-GC) is expected to be one of the useful methods for clarifying structural characteristics of lignin in mechanical pulps. In the structural analysis by Py-GC, lignin can be analyzed without being isolated from pulps. Papers which contain mechanical pulps is expected to be characterized by Py-GC. In this report, Py-GC was applied to the characterization of lignin in thermomechanical pulps (TMP) of softwoods and various kinds of papers.

Six species: akamatsu (Pinus densiflora), ezomatsu (Picea jezoensis), karamatsu (Larix kaempferi), spruce (Picea sp.), Douglas-fir (Pseudotsuga menziesii), todomatsu (Abies sachalinensis ), which were used as raw materials of mechanical pulps, were analyzed by Py-GC. The eight main lignin-derived pyrolysis products (guaiacol, 4-methylguaiacol, 4-vinylguaiacol, vanillin, trans-isoeugenol, dihydroconiferyl alcohol, coniferaldehyde and trans-coniferyl alcohol) were detected. Comparing the pyrolysis products of woods, different yields of trans-coniferyl alcohol between the species were observed. Spruce and Douglas-fir showed high yields of trans- coniferyl alcohol, whereas akamatsu and todomatsu did low yields.

At a laboratory, thermomechanical pulp were made from Akamatsu and ezomatsu wood, and analyzed by Py-GC. The yields of the main pyrolysis products were not changed by thermomechanical pulping. The pyrogram patterns of lignin in wood materials were kept after thermomechanical pulping.

Py-GC was applied to the characterization of lignin in seventeen kinds of papers: printing and writing papers (wood containing paper, woodfree paper, and wood containing coated paper). Some pyrolysis products from lignin were detected in the analysis of several papers including mechanical pulp. Their characteristics of pyrogram suggested those of the mechanical pulp. Py-GC is more useful than other methods such as alkaline nitrobenzene oxidation because it provides more information on degradation products than alkaline nitrobenzene oxidation. Py-GC was found to be unaffected by filler in paper, while filler usually interfered with exact measurement of the Klason lignin. A kind of paper including hardwood mechanical pulp was clearly distinguished from the others by the detection of syringyl type pyrolysis products. It was considered that the higher yields of the pyrolysis products by Py-GC and the aldehydes by alkaline nitrobenzene oxidation showed the presence of mechanical pulps in papers in higher ratio. When a pyrogram of mechanical pulp is known, it seems to be able to distinguish the paper including the pulp from the others.

Kami Pa Gikyoushi, 51(6), 932-944 (1997)

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5-Hydroxyguaiacyl nuclei as aromatic constituent of native lignin.

Satoshi Suzuki*, Thi Bach Tuyet Lam** and Kenji Iiyama*

* Asian Natural Environmental Science Centre. The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113, Japan;
**School of Biochemistry, La Trobe University Bundoora Victoria 3083 Australia
The pathway of lignin biosynthesis has been well documented. However, there are still questions because of the lack of knowledge about the exact chemical structure of lignin, caused by the restriction of analytical procedures used and/or the interpretation of analytical results. The presence of 5-hydroxyguaiacyl nuclei in lignin of a brown midrib mutant (bm3) of maize has been established using a thioacidolysis. In this paper, it was confirmed using pyrolysis-gas chromatography-mass spectrometry (PY-GC/MS) that in addition to bmr mutants of some tropical grasses, lignins of their normal counterparts and some temperate and tropical angiosperms woody plants are composed of 5-hydroxyguaiacyl nuclei, in addition to guaiacyl and syringyl nuclei. Based on the results, it is suggested that 3(3,4-dihydroxy-5-methoxyphenyl)-propen-1-ol, which is synthesised from 3 (3,4-dihydroxy-5-methoxyphenyl)-propionic acid (5-hydroxyferulic acid) is also involved in dehydrogenative polymerisation by perioxidase during the biogenesis of lignin of some species of plants.

Phytochemistry, 46 (4), 695-700 (1997)

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Structural characteristics of lignin and wall polysacchaides in steam exploded pulps of oil palm (Elaeis guneensis Jaxq.) frond relating to self-binding mechanism of binderless boards prepared from them

Satoshi Suzuki, Hiroyuki Shintani, Seung-Young Park, Keiko Saito, Nikhom Laemsak, Motoaki Okuma and Kenji Iiyama

Oil parm (Elaeis guineensis Jacq.) is one of the most abundant, unutilised waste biomass from plantation in South-Asia. The binderless boards were prepared from steam-exploded pulps of oil palm fronds and characterrised for the mechanical strengths and chemical natures to discuss mechanism of self-binding. The mechanical strength of these boards satisfied the requirements of the relevant standard specifications (JIS: Japanese Industrial Standards) for the boards. To make clear mechanism of the self-bonding of these binderless boards, oil palm fronds themselves, their steam exploded pulps, boards and lignins isolated by Björkman's procedure from extract-free oil palm fronds and steam exploded pulps, were analysed by chemical and spectrometrical methods and pyrolysis-gaschromatography/mass spectrometry.
Lignin of oil palm frond was characterised by the presence of significant amounts of esterified p-hydroxybenzoic acid together with small amounts of etherified p-hydroxybenzoic acid. Vanillic and siringic acids were esterified or etherified to lignin. Some extents of these ester bonds and beta-O-4 interunit linkages of lignin were cleaved during steam explosion, in addition to great condensation of guaiacyl nuclei, as revealed by 1H- and 13C-NMR spectra of isolated lignins from the steam exploded pulps, of which yields were quite high, suggesting that lignin has been released from other wall polymers. Wall polysaccharides of oil palm frond are composed of cellulose and significantly high concentration of arabinoxylan, which produced great abundance 5-hydroxymethyl-furfural and furfural during steam explosion, respectively, and even hot pressing at 125�‹C to prepare binderless boards. It is suggested that released lignin and furfural derivatives generated during steam explosion contribute to self-binding of the steam exploded pulps. However, severe conditions of steam explosion caused great damages in lignin macromolecules, and gave poor quality of binderless board.

Holzforshung, 52 (4), 417-426 (1998)

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Compositional and structural characteristics of residual biomass from tropical plantations

Satoshi Suzuki, Evelyn B. Rodriguez, Kyoko Saito, Hiroyuki Shintani, Kenji Iiyama

Abstract Many products and abundant wastes from tropical plantations. such as latex. palm oil. and coconut production due to replantation. are waiting effective utilization. Nonutilized tropical biomass - oil palm (Elaeis guneensis Jacq.), coconut (Cocos nuclfera L.) coir dust and coir fiber, and rubber (Hevea brasiliensis ) wood - were analyzed for chemical and structural characteristics of wall polysaccharides and lignin. Coconut coir dust is mostly composed of middle lamella and is separated from coir fiber. which is composed of secondary walls. These were supported by lignin content. and structural characteristics of wall polysaccharides and lignin. The chemical and spectroscopic characteristics of walls of rubber xylem were similar to those of typical temperate angiosperm woods. Oil palm frond was significantly rich in arabinoxylan. and numerous acetyl groups were substituted to the arabinoxylan. Lignin of oil palm frond and wall polysaccharides of coconut coir dust are substituted with hydroxybenzoic acids with ester and ether linkages. Some p-hydroxybenzoic acid substituted to the wall polymers of coconut coir dust would contribute to the formation of associations between polysaccharides and lignin. Based on the above results it is suggested that coconut coir fiber and rubber wood are suitable resources for chemical pulp production for paper-making. but oil palm frond is not.

Journal of Wood Science, 44 (1), 40-46 (1998)

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Structural analysis of alkaline cooked lignin by pyrolysis-gas chromatography evaluation of uniformity in delignification of beech wood chips

Satoshi Suzuki*, H.Ohi*, K.Kuroda*, A.Izumi*, A.Yamaguchi*

*Institute of Agricultural and Forest Engineering. The University of Tsukuba, Tsukuba, Ibaraki, 305, Japan
Recently, pyrolysis-gas chromatography (Py-GC) becomes one of the effective methods for characterizing synthetic and natural polymers because this method enables rapid analyses using very small samples. Lignin in woods can be analyzed by Py-GC without any sample preparation. In this report, uniformity in delignification of beech wood chips was presented. Pyrolysis of kraft, . soda, Soda-THAQ and sulfite-THAQ pulps produced following compounds: guaiacol, 4-methylguaiacol, 4-vinyl-guaiacol, vanillin, trans-isoeugenol, syringol, 4-methylsyringol, 4-vinyl-syringol, syringaldehyde and trans-4-propenylsyringol. Kraft, soda and soda-THAQ pulps indicated a high correlation between the ratios of syringyl derivatives to guaiacyl derivatives (S/G) from pyrograms and the Klason lignin contents; the correlation factor was 0.97. Thus, the determination of the S/G ratios enabled tc estimate the Klason lignin contents of beech pulps. In sulfite-THAQ pulps, variation of S/G ratios according to the decrease of Klason pulps, v lignin contents of pulps was small. Uniformity in delignification of beech wood chips after kraft cooking could be evaluated by measuring the S/G ratios of wafers of the chip. As delignification during alkaline cooking proceeded, relative yields of guaiacol and syringol to those of the other pyrolysis products from residual lignin in pulps increased.

International symposium on Fiber science and Technology, Yokohama, Japan, (1994)

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Analysis of Lignin in Various Kinds of Paper by Pyrolysis-Gas Chromatography

Satoshi Suzuki, Hiroshi Ohi, Ken-ichi Kuroda and Akira Yamaguchi

Pyrolysis-gas chromatography (Py-GC) is expected to be one of the useful methods for clarifying structural characteristics of lignin in various kinds of paper. The method is more useful than other methods such as nitrobenzene oxidation (ANO) because it provides more detailed information on degradation products than ANO. Py-GC should be unaffected by filler in paper, while filler usually interferes with exact measurement in the Klason lignin method. In this study, Py-GC was applied to the characterization of lignin in seventeen kinds of paper, printing and writing paper (wood containing paper, woodfree paper, and wood containing coated paper). Several pyrolysis products from lignin were detected in the analysis of all kinds of papers including mechanical pulp. A kind of paper including hardwood mechanical pulp was clearly distinguished from the others by the detection of syringyl type pyrolysis products. It was considered that the higher yields of both the pyrolysis products and the aldehydes by ANO showed the presence of mechanical pulps in paper in higher ratio. When a pyrogram of mechanical pulp is known, it seems to be able to distinguish the paper including the pulp from the others.

The Proceedings of 1995 (62nd) Pulp and Paper Research Conference, Tokyo, June 2, p.86-91 (1995)

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Analysis of Lignin in Thermomechanical Pulp by Pyrolysis-Gas Chromatography

Satoshi Suzuki, Hiroshi Ohi, Ken-ichi Kuroda

Pyrolysis-gas chromatography (Py-GC) is expected to be one of the useful methods for clarifying structural characteristics of lignin I '2). Recently, Py-GC becomes one of the powerful tools for analyses of synthetic polymers. Very small amounts of solid materials are analyzed rapidly by using Py-GC. In the structural analysis of lignin in woods, lignin can be analyzed by Py-GC without being isolated from woods. In this report, Py-GC was applied to the characterization of lignin in thermomechanical pulps of softwoods.
Several pyrolysis products from lignin were detected, and their yields were not changed by thermomechanical pulping of wood. It means that the fragmentation patterns of lignin in wood materials were kept after thermomechanical pulping. The irradiation decreased the yield of trans-coniferyl alcohol. It might mean that the end group of coniferyl alcohol types in lignin could be degraded.

International Symposium of Cellulose and Lignocellilosis '96, Guangzho, China, June 6-8, p.177-178 (1996)

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Preparation of Binderless Boards from Steam Exploded Pulp of Oil Palm Frond and Structural Characteristic of Lignin in Steam Exploded Pulp

Satoshi Suzuki*1 , Hiroyuki Shintani*1 , Seung-Young Park *1, Nikhom Laemsak*1, Motoaki Okuma*1 , Kenji Iiyama *2

*1 Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113 Japan. *2 Asian Natural Environmental Science Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113 Japan.
The binderless boards were prepared from steam exploded (2.0-3.0MPa, 5-10min) pulps of oil palm frond. The strength of these boards met the requirements of the boards of JIS. To clarify the mechanism of the bonding of the binderless boards, oil palm frond, pulp and board were analyzed by the chemical and spectrometical methods and pyrolysis-gas chromatography mass spectrometry.

Bjorkman lignin from oil palm frond, and this lignin was characterized by the presence of significant amount of esterified p-hydroxybenzoic acid. Most ester bonds and b-O-4 bonds were cleaved during steam explosion process, and the other hand, guaiacyl units were condensed greatly, as revealed by 1H and 13C-NMR spectra. Moreover, the structural difference of the aromatic units between 2.5MPa and 3.0MPa exploded pulp, were observed in 1H, 13C-NMR and FTIR spectra. The ratios of syringyl derivatives to guaiacyl derivatives (S/G) from total ion pyrograms were decreased by hot pressing.

As a result of the analytical pyrolysis, 5-hydroxymethylfurfural, derived from cellulose, was increased by the steam explosion especially 3.0MPa. Significant amount of furfural, derived from pentosan, was detected in the pulp steam exploded under the condition of 2.5MPa, and furfural was increased during hot pressing. These facts suggest that furfural is involved in the formation of binder together with lignin.

Proceedings of The 41st Lignin Symposium, Nagoya Japan, Oct. 3-4, p.73-76 (1996)

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5-Hydroxyguaiacyl Nuclei in Native Lignin

Kenji Iiyama*1, Satoshi Suzuki*2, Thi Bach Tuyet Lam*3

*1Asian Natural Environmental Science Center, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113 Japan. *2Graduate School of Agriculture and Life Science, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113 Japan. *3School of Biochemistry, La Trobe University, Bundoora, Vic., 3083 Australia.
The pathway of lignin biosynthesis has been well documented. However, there are still questions because of lack of knowledges of the exact chemical structure of lignin, which would be caused by the restriction of analytical procedures used and/or the interpretation of analytical results. The presence of 5-hydroxyguaiacyl nuclei in lignin of a brown midrib mutant (bm3) of maize has been published using a thioacidolysis.
In this paper, it was confirmed using a pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) that in addition to bmr mutants of some tropical grasses, lignins in their normal counterparts and some temperate and tropical angiosperms woody plants are composed of 5-hydroxyguaiacyl nuclei. Based on the results, we propose the modification pathway for lignification.

Proceedings of The 41st Lignin Symposium, Nagoya Japan, Oct. 3-4, p.37-40 (1996)

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Pyrolysis-Gas Chromatographic Analysis of Ferulic acid Generated in Softwood Thermomechanical Pulps during Light Irradiation

Satoshi Suzuki*1,3 , Hiroshi Ohi *2

*1 Asian Natural Environmental Science Center, The University of Tokyo, 1-1-1
Yayoi, Bunkyo-ku, Tokyo 113, Japan
*2 Institute of Agricultural and Forest Engineering, The University of Tsukuba,
Tsukuba, Ibaraki 305, Japan
*3: Present Address: Toyama Forestry and Forest Products Research Center,
4940 Kurokawashin Kosugi-machi Imizu Toyama 939-03, Japan
Pyrolysis-gas chromatography (Py-GC) becomes one of the powerful tools for analyses of synthetic polymers, and useful methods to investigate structural characteristics of lignin. The structure of lignin in plant cell walls is characterized rapidly by Py-GC without any pretreatment using very small amounts of solid materials. In this paper, Py-GC was applied to characterize structural feature of lignin in thermomechanical pulps (TMP) of akamatsu (Pinus densiflora) and ezomatsu ( Picea jezoensis) woods.

There were no significant differences in yields of pyrolysis products from lignin between thermomechanical pulps and original wood meal, suggesting that the structural feature of lignin in wood materials has not been changed during thermomechanical pulping. Terminal groups of coniferyl alcohol types in lignin could be degraded after light irradiation of TMP sheets. Ferulic acids in TMP, TMP irradiated and original woods were analyzed by on-line methylation Py-GC using tetramethylammonium hydroxide. No ferulic acid were detected at all in those samples. These results suggest that formation of ferulic acid would not contribute to the yellowing of TMP.

9th International Symposium on Wood and Pulping chemistry Poster Presentations , Montréal, Canda, June 9-12, p.110-1-110-4 (1997)

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Preparation of Binderless Boards from Steam Exploded Pulp of Oil Palm Frond

Satoshi Suzuki, Hiroyuki Shintani, Nikhom Laemsak, Kyoko Saito, Motoaki Ohkuma and Kenji Iiyama

The binderless boards were prepared from steam exploded pulps of oil palm (Elaeis guineensis Jacq.) fronds and characterised for the mechanical strengths and chemical natures to discuss self-binding. The mechanical strength satisfied the requirements of the relevant standard specification. To discuss the self-bonding of these binderless boards, lignin isolated by Björkman's procedure from oil palm fronds and steam exploded pulps, were analyzed by wet chemistry and Py-GC/MS. Lignin of oil palm frond was characterised by esterified p -hydroxybenzoic acid. Some extents of these ester bonds and ß-O-4 linkages of lignin were cleaved during steam explosion, in addition to great condensation of guaiacyl nuclei, as revealed by 1H- and 13C- NMR spectra. Wall polysaccharides of oil palm frond are composed of high concentration of arabinoxylan, which produced furfural during steam explosion. It is suggested that released lignin and furfural derivatives contribute to self-binding of the steam exploded pulps.

9th International Symposium on Wood and Pulping chemistry Oral Presentations , Montréal, Canda, June 9-12 p.I1-1-I1-4 (1997)

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Last Up Date: 2001/07/25