1988 Fiscal Year Final Research Report Summary
Chemical Modification of Bark Extracts to Prepare High Quality Resins.
| Project/Area Number |
62560175
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
林産学
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| Research Institution | Mie University |
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Principal Investigator |
ABE Isao Faculty of Bioresources (Faculty of Agriculture), Mie University, Professor, 生物資源学部(農学部), 教授 (20024581)
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| Co-Investigator(Kenkyū-buntansha) |
FUNAOKA Masamitu Faculty of Bioresources (Faculty of Agriculture), Mie University, Associate Prof, 生物資源学部(農学部), 助教授 (50093141)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Condensed tannin / Phenyl nucleus-exchange reaction / Phenolic pattern of tannin / Acidity function H_0 / Phenolation of natural polyphenol / タンニン系 / 樹脂接着剤 |
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| Research Abstract |
1) Characteristics of Condensed Tannins.
Chemical characteristics of wattle and quebracho tannins and the bark extracts from some species of coniferous trees were elucidated by a method combining the standard phenyl nucleus-exchange method (the NE-reaction) using BF_3 catalyst and the conventional techniques for estimating of the general aspects of the tannin.
2) Phenolation and the NE-reaction of Condensed Tannin.
By the treatment of condensed tannins with reagents composed of phenol and acidic catalysts, their constituent nuclei were liberated by the NE-reaction, via phenolation with phenols added as a medium in the systems. From the experimental results used bronsted acid as a catalyst, decreasing the reaction rates was observed with increasing water contents in the systems and such inhibitory effects of water were estimated to be due to the decreasing the acidity, determined as an acidity function H_0, of the system.
3) Chemical Modification of Condensed Tannin by Phenol-Water Reaction
… More
System.
The phenolation of tannin in the phenol-water-acid systems was tried to cleave of flavonoid etherocyclic rings, leading to grafting of phenols in the systems at position C-2, for the purpose of leaving out of the steric hindrance of the molecule. The experimental results show that the phenolation and the NE-reaction took place in the compound at the same time, and the phenolation rate was increased with increasing the electronegativity of phenols used as medium and the acidity of the systems.
4) The Property of Tannin-Based wood Adhesive.
The properties of tannin-based resins as cold- or hot-setting adhesives prepared by chemical modification with resorcinol or phenol were tested. The resorcinol-tannin adduct prepared by 1 mole of tannin and 1.05 moles of resorcinol and exhibit a reasonable cold-setting properties. On the other hand, the phenol-tannin adduct by phenolation showed suitable hot-setting abilities. However, further improved approaches are necessary to make durable and fast curing natural resins corresponded to that of the synthetic resins. Less
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