Post on 10-Oct-2015
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Extractive Components
of Wood
Barbara ColeUniversity of Maine
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CO2H
Major Components of Wood
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Wood Extractives
- Non-cell wall components
-Can be removed using solvents,
e.g. pet. ether, acetone, ethanol, water
- Relatively small molecules (< C40)
- Usually comprise 1-5% of the wood
- Under genetic control vary by species
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Lipid Extractive Components
I. Aliphatics
Fats (fatty acid esters of glycerol): 0.3-0.4%
Fatty acids:
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Suberin (polyester):
Fatty alcohols (C16-C28):
Waxes (esters of other alcohols):
CH3-(CH2)n-O-CO-(CH2)m-CH3
C20H41OH (Eicosanol)
[-O-(CH2)n-CO-] n= 18-28
Fatty acidAlcohol
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Lipid Extractive Components
II. Terpenoids: primarily in softwood species
Monoterpenes (C10)
a-Pinene b-Pinene Limonene
Uses: Turpentine, flavor and fragrance chemicals
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Lipid Extractive Components
II. Terpenoids: primarily in softwood species
Diterpenes (C20) (0.2-0.8% of wood)
CO2H
Abeitic Acid Pimaric Acid
CO2H
Uses: Rosin, sizing agents
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Lipid Extractive Components
II. Terpenoids:
Triterpenes (C30) (5-30% in birch bark)
HO
CH2OH
Betulin
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Phenolic Extractive Components
I. Simple Phenolics
CO2H
HO
OH
OH
Gallicacid
CHO
OH
OCH3
Vanillin
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Phenolic Extractive Components
II. Stilbenes
HO
HO
Pinosylvin
Stilbenes are generally very toxic!
Primarily in the heartwood of conifers.
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Phenolic Extractive Components
III. Flavonoids
HO
OH
OH
OH
OH
O Taxifolin
- Flavonoids are the most abundant phenolics.
-Coloration in foliage and flowers, astringent taste in unripe fruits.
-Condensed tannins: tanning agents, adhesives
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Phenolic Extractive Components
IV. Lignans
HC
HCO
CH2
CHH2C CH
O
OH
OCH3
OH
CH3O
Pinoresinol
Generally non-toxic and are very good antioxidants.
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Other Extractive Components
I. Alkanes
II. Proteins
III. Monosaccharides and derivatives
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Summary
- Extractive components are small molecules that can beextracted with a solvent from wood, bark, or foliage.
-Generally, extractives are present in small amounts.
-Extractives vary tremendously within species, between
species, and within trees.
-There are thousands of different extractives present in
wood.
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Softwoods:- Resin acids: 40-45% of extractives
- Fatty acids: 40-60%
- Monoterpenes (turpentine)- Phenolics
Hardwoods:- No resin acids or monoterpenes
- Fatty acids: 60-90%
- Phenolics
Softwoods vs. Hardwoods