Download 406-14 Fats Waxes and Lignans

Wood Chemistry
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Wood Chemistry
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Lecture 14
Fats/Waxes/Lignans
PSE 406 Lecture 14
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Tall oil
Waxes
Lignans
» Chemistry
» Role in the tree
» Commercialization
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What are Fats and Oils?
PSE 406 Lecture 14
Wood Chemistry
Both you and I recognize
fat when we see it. We
also probably know that
fat and oils are energy
storage material.
Fats and oils are similar
chemically: the difference
is that fats are solids at
room temperature and
oils are liquids.
PSE 406 Lecture 14
Fats and Fatty Acids
» Chemistry
» Role in the tree
PSE 406/Chem E 470
Wood Chemistry
Agenda
Wood Chemistry
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Chemical Composition of
Fat/Oils
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Esters of long chain fatty acids
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Trigylcerides, diglycerides, & monoglycerides
Similar structures in all plants. What varies is the fatty acids
attached to the glycerol and the percentage of tri, di, and
monoglycerides
» Most often with glycerol
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H2C O CO R1
H2C O CO R1
H2 C O CO R2
H 2C O CO R2
H 2C O CO R1
H2C OH
H 2C O C O R3
H2C OH
H2 C OH
Diglyceride
Triglyceride
Monoglyceride
O
H2C O C
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Wood Chemistry
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Chemical Composition of Fatty
Acids
Wood Chemistry
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Fatty acids are long chained carboxylic acids
» Mostly even numbered chains
– 20-22 less common
» 80% unsaturated: 1, 2 or 3 double bonds
Secondary Fatty Acids
COOH
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COOH
Palmitic acid (C16)
Oleic acid (C18)
There are high levels of fats in seeds.
» Corn and soybeans contain 10-20% oils.
» Canola and sunflower contain up almost 50%
oils.
» Nuts 50-70% oils
– 16-18 carbons most common
Major Fatty Acids
Fat (Oil) Content
COOH
In agricultural crops the majority of the oils
are triglycerides.
COOH
Linolenic acid (C18)
COOH
Linoleic acid (C18)
Eicosadienoic acid (C20)
PSE 406 Lecture 14
Wood Chemistry
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Fats in Trees
Wood Chemistry
Free Fatty Acids
Most fatty acids are linked as esters to other
components (glycerol, sterols, etc) in the
cells.
l A small amount of free fatty acids are present
in plants. (not according to Encyclopedia Britannica)
Function
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» Fats role in trees is the same as in your waist
line: serves as a storage material.
» The amount of fat in the tree is seasonally
dependent.
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Fats are found in living cells - parenchyma
» Very low content (1 -2%) in oleoresin.
» More present in sapwood than heartwood.
» High content in many nuts.
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PSE 406 Lecture 14
Roles of free acids:
» Disease resistance (messengers)
» Other?????????
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PSE 406 Lecture 14
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Fats & Fatty Acids
Composition in Wood
Wood Chemistry
Picea abies
a
% of wood
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b
Pinus Syv.
Populus Tr.
% of wood
% of wood
Fatty Acids
0.08 (29%)
0.17 (24%)
0.11 (9%)
Fats
- Trigylcerides
0.12 (45%)
0.53 (72%)
0.98 (78%)
- Digylcerides
c
0.02 (3%)
0.05 (4%)
- Monoglycerides 0.03 (13%)
0.01 (2%)
0.11 (9%)
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OH
OH
-
HOCH2CHCH2OH
O
H2C O C
R
Glycerol (glycerine)
OH
H2O
O
H2C OH
-
O C
R
PSE 406 Lecture 14
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Fats & Fatty Acids
Pulp and Paper Issues
Fats and fatty acids are not water soluble and
are therefore involved in the formation of
stickies .
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Tall Oil Production
Turpentine
Pulp
Recovery Furnace
Washers
Evaporators
pulp
Chips
Digester
liquor
Intermediate
Liquor
Fatty acids are often recovered along with
resin acids from kraft mills. This combination
of chemicals is known as tall oil.
PSE 406 Lecture 14
PSE 406 Lecture 14
Wood Chemistry
» Remember that these chemicals are found in
little parenchyma cells. Beating of pulp can
release this material.
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Treatment of fats with alkali converts them to fatty
acids and glycerol through saponification.
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H 2C O C
a: Norway spruce
b: Scotch pine
c: European aspen
1: % of total fatty material
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0.03 (13%)
Wood Chemistry
Saponification of Fats
Wood Chemistry
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Crude Tall
Oil
Acidulation
Unit
PSE 406 Lecture 14
Soap
Skimmer
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Wood Chemistry
Product
TOR
TOFA
DTO
Heads
Pitch
Tall Oil Fractionization
Temp < 260°C
Yields
32%
28%
8%
10%
18%
Vacuum
Crude
Fatty Acids
Fatty
Acids
Pitch
Rosin
Wood Chemistry
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Waxes
CH3 (CH 2) n O CO ( CH2 )m CH 3
C2 0H 41OH
C24H 49 OH
Arachidic Alcohol
Lignoceric Alcohol
PSE 406 Lecture 14
Wood Chemistry
Other components found in waxes include n-alkanes,
ketones, primary and secondary alcohols, aldehydes,
dicarboxylic acids, and hydroxy acids.
Minor wood component
Physical Properties
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» Soluble in organic solvents. Water insoluble
» mp/bp: think candles
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PSE 406 Lecture 14
Waxes
Distilled
Tall Oil
» 0.08-0.09%
» Much higher percentage in foliage, fruits and some barks.
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Wax is the water
resistant protective
coatings of leaves, fruits,
and trees (bark). Wax is
a mixture of a variety of
different chemicals.
» Waxes consist mainly of
very long chained (C12-38)
fatty acid esters of long
chained alcohols.
PSE 406 Lecture 14
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Heads
Depitched
Crude
Tall Oil
Waxes
No Air
Heads
Tall Oil
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Wood Chemistry
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Lignans
Another class of extractive
produced by the plant for
protection.There are large
numbers of different lignans.
Lignans are found in the bark,
fruit, heartwood, leaves, and
roots of plants.
Isolation is accomplished
though solvent extraction.
Yields of 0-30% are obtained.
PSE 406 Lecture 14
O
CH3O
O
HO
OCH3
OH
α-Conidendrin
Example lignan found
In heartwood of softwoods
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Lignans
Wood Chemistry
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Structural Information
» Comes through same biosynthetic
pathway as lignins
» C9 units linked through enzymatic free
radical coupling
» Protein found which acts as template to
force β-β orientation
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γ C
Two phenylpropane units (C9) linked
β−β
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β C
1
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2
3
» Ring substitution (3, 4, 5)
» Nature of linked side chain
» Nature of additional bonds between
rings
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OCH3
In trees, lignans are laid down at the
sapwood/heartwood boundary.
» They are laid down when the tree is depositing
chemicals to protect itself.
OH
PSE 406 Lecture 14
Wood Chemistry
Many lignans have fungicidal, insecticidal,
and antioxidant properties.
» Hydroxymatairesinol actually consumed by fungi
accelerating degradation.
α C
Lignans differ in:
Lignans: Role in the Plant
Wood Chemistry
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Lignans
Lignans: Location in Tree
Typical Softwood Species
Wood Chemistry
O
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O
Widely distributed in softwoods and hardwoods
H2 C
HC
CH2
» Typically amount: < 1% of heartwood
» Can be as high as 30% of heartwood
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Found in Heartwood
CH3O
CO
CH
CH2
HO
OH
» Nearly non existent in sapwood
» In Tsuga, lignans were found lining the tracheid walls
as surface coatings and encrusting bordered pits
» Lignans deposited during heartwood formation
» Greatly responsible for coloration of heartwood
OH
OCH3
OH
OH
α -Conidendrin
Matairesinol
CH2
CH2
CH
OH
OCH3
CH3 O
H2C
CH
CH
O
Hinokiresinol
OH
OCH 3
H2COH
HC
HC
H2C
H2COH
CH
CH2
O
HC
HC
CH
CH
O
CH
OCH3
CH3 O
OH
OH
CH 3O
OH
Pinoresinol
Isolariciresinol
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Lignans
Wood Chemistry
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Lignans
Medicinal uses
Wood Chemistry
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Large amount of research devoted to investigating
medicinal properties of lignans.
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– Example 1999 reference: 35 lignans isolated from the twigs of
Tazus mairei (a shrub) for possible use as drugs.
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Lignans are phytoestrogens
» These are compounds produced by plants which are
similar in structure to oestrogen and ehibit oestogenicity.
PSE 406 Lecture 14
Also found in mayapple: common
American weed
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Sold by Bristol-Myer
Squibb as VePesid
Treatment for testicular
cancer and small lung
cancers and others.
Glycoside (sugar
containing) of
Podophyllotoxin
O
CH3
Wood Chemistry
OCH3
OCH3
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Nordihydroguaiaretic Acid
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Isolated from the leaves of
Larrea divaricata
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NDGA is a proven
antioxidant
» 12% yield
O
O
OH
O
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O
O
HO
HO
» Used in fats and oils in food.
O
CH3O
CH3O
PSE 406 Lecture 14
O
HO
O
Lignans
Example Uses: Etoposide
H
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O
O
Functions as cell poison: affects cells
undergoing mitosis.
Inhibits enzyme needed for cancer cell
reproduction.
Starting material for the manufacture of
other cancer drugs.
Lignans
Wood Chemistry
OH
O
» Extracted from leaves
Studies have found certain medicinal properties:
» Antiviral, antitumor , antioxidant
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Extract of Phodophyllum emodi
» Asian plant
» Material in root (rhyzomes )
» Particularly from tropical hardwoods and grasses.
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Example Uses: Podophyllotoxin
Produced synthetically
from petroleum based
starting material.
OH
OH
OCH3
OCH3
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Wood Chemistry
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Lignans: Industrial Problems
Lignans found in water discharge from
mechanical pulping operations
» Toxic to fish but not as much as other extractive
compounds
» Are readily handled through biological treatment
systems
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Plicatic acid has been found to be the number one
cause of respiratory problems in cedar saw mills
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