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Wood Chemistry Chemistry Agenda

l General Extractives Information Wood Chemistry l PSE 406/Chem E 470 » – Chemistry – Occurrence Lecture 12 – Uses Wood Extractives Introduction » Terpenes and Sesquiterpenes

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Wood Chemistry Extractives (1) Wood Chemistry Tree Extractives (2)

l Besides the big three wood compounds, l Extractives add contain other compounds that serve a variety significant properties to wood: of functions including: » Color » Protection (from insects, , and rot). » Odor » Attractants (flowers, fruits) » Density l These compounds are » Food storage typically present in very » Membranes limited amounts but still » Enzymes affect the wood properties greatly.

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1 1 Wood Chemistry Protection Chemicals Wood Chemistry “Other Extractives”

l Here is a list of the classes of extractives that can serve to protect the tree. We will look at most of these. l These extractives are in the tree typically for » Terpenes reasons other than protection. » Acids » Fats and fatty acids » Flavonoids » Proteins » Lignans » Flavonoids (I know they are involved in » Stilbenes protection). » Tannins » Sterols » Phenolics and others

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Softwood Fragrance

Wood Chemistry The Fragrance of a Tree Wood Chemistry Chemicals

l Each tree has a unique fragrance. l The fragrance of softwood » Some have strong fragrances. trees are typically from a than others like Cedar. class of chemicals named » Some have only light odor terpenes. l The aroma is due to volatile compounds produced by the l Terpenes are tree. (the odor chemicals derivatives of ; a become gases easily) chemical that can be l These chemicals can be produced from petroleum. isolated and sold.

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2 2 Terpenes/ Wood Chemistry General Structures Wood Chemistry Structures

H2 C l of Isoprene. l Hydrocarbon derivatives of l Over 4000 have been isoprene (2-methyl butadiene) » Butadienes linked head to tail CH2 identified in trees. H3C Isoprene Monoterpenes Sesquiterpenes l Can posses oxygen containing 1 * 5C 2 * 5C l Isoprene linked 3 * 5C (s) such as according to “isoprene alcohols, carboxylic acids, and rule”. aldehydes l : l Stereospecific (±)

l : contains l Acyclic, monocyclic, bicyclic, and 4 * 5C oxygen containing 6 * 5C trycyclic compounds Isoprene functional group. 1 * 5C

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Wood Chemistry Monoterpene Structures Wood Chemistry Monoterpenoids

Acyclic Moncyclic Tricyclic OH l Monoterpenes which O consist of only and hydrogen are OH hydrocarbons. b Thujaplacin tricylene l Addition of functional Bicylic Class groups such as OH, CHO Carane Type Thujane Type Pinane Type Bornane Type COOH, Aldehydes, COOH etc. turn these

monoterpenes into Thujic acid Safranal monoterpenoids. 3-carene a- a - PSE 406 Lecture 12 11 PSE 406 Lecture 12 12

3 3 Monoterpenes (oids) Wood Chemistry Physical Properties Wood Chemistry Monoterpenes Occurrence

l Form l Found both in vegetative and kingdoms: » Mostly liquids, some solids both terrestrial and marine. l Melting Points l Vegetable kingdom » a -pinene: - 50 °C » Widely distributed in higher : roots, stem, foliage, seeds. » : 179°C (solid at room temp) » Trees: exist mainly in softwoods, some tropical . l Boiling Points Often responsible for the characteristic odor of wood. » Typically found in oleoresin. » a -pinene: 156 °C @ 101.3 kPa a-Pinene » nerolidol: 276°C @ 101.3 kPa l Animal Kingdom l Solubility O » Insects (warning compounds, attractants)/Alligators » Monoterpenes: organic , l Volatile compounds released during pulping. insoluble in water l Monoterpenoids widely used commercially: » Monoterpenoids: organic solvents with » / Oil some limited water solubility Camphor

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Composition of Douglas Fir Monoterpenes (oids) Wood Chemistry Terpenes Wood Chemistry Environmental Issues (1)

OH l Trees naturally release terpenes so there is a certain level of terpenes in the atmosphere OH 3 a-Pinene » Typical forest (~100 ug/m ) 58.4% a-Terineol/ b-Phellandrene/ a- l Terpenes as hydrocarbons react in the 6.6% 6.3% atmosphere with oxygen and sunlight to form photooxidants (O3, H2O2, HO•, HOO•, RONO2, etc.) OH » These species cause damage to forest.

b-Pinene Terpinene-4-ol Camphene 3-carene 4.2% 2.5% 2.4% 1.5%

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4 4 Monoterpenes (oids) Monoterpenes (oids) Wood Chemistry Environmental Issues (2) Wood Chemistry Chemical Sources: Turpentine

l Trees of the species Pinus are the source of l Logging and wood processing operations significantly increases the level of terpenes in the atmosphere (10 nearly all turpentine – 1000 times higher than natural forests. l Four classifications of turpentine: l Increased levels of terpenes can cause damage to » Gum - from wounds on tree the forest and to humans. » Steam distilled wood - steaming of old stumps » Inhalation of terpenes can also cause certain health problems. » Sulfate wood turpentine - vented from kraft » Mill sites can have very high levels of terpenes. pulping » - not commercially significant

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Monoterpenes (oids) Wood Chemistry Chemical Sources: Turpentine Wood Chemistry Sesquiterpenes

Country Tons Country Tons USA/Canada 108,00 Mexico/ 10,000 l Volatile compounds: isolated by steam distillation 99% CST, 1% Gum Central Am. 60% Gum, 40% CST » Components of turpentine South Am. 17,000 Scandinavia 22,000 l 90% Gum, 10% CST 100% CST 3 isoprene units linked head to tail Russia 91,000 Southern 6,800 l Found in most plants and fungi. Typically very 90% CST, 10% Gum Europe 95% Gum, 5% CST minor components. China 47,000 New 3,900 100% Gum 100% CST O Zealand O Indonesia 8,400 India 4,800 Mostly gum 100% Gum Miscellaneous 17,500 Total 335,000 Tons World (metric) g-Muurolene Mansonone C Source: Amazing Terpenes 1993 PSE 406 Lecture 12 19 PSE 406 Lecture 12 20

5 5 Wood Chemistry Role of Sesquiterpenes

l Used to control other plants in a deleterious fashion. (Allelopathy) l Anti bacterial compounds (Phytoalexins) l Used by fungi to break down plants () l Defensive chemicals used by plants against insects and fungi

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