PSE 406 Lecture 121 Wood Chemistry PSE 406 Lecture 12 Wood Extractives

PSE 406 Lecture 122 Agenda lGeneral Extractives Information –Classes –Chemistry –Occurrence –Uses

PSE 406 Lecture 123 Tree Extractives (1) lBesides the big three wood compounds, trees contain other compounds that serve a variety of functions including: »Protection (from insects, animals, and rot). »Attractants (flowers, fruits) »Food storage lThe amount of extractives in wood can range from 1- 20% (species, position in the tree, season, geographical location) lMore in heartwood

PSE 406 Lecture 124 Tree Extractives (2) lExtractives add significant properties to wood: »Color »Odor »Density lThese compounds are typically present in very limited amounts but still affect the wood properties greatly.

PSE 406 Lecture 125 Protection Chemicals lHere is a list of the classes of extractives that can serve to protect the tree. »Terpenes »Resin Acids »Flavonoids »Lignans »Stilbenes »Tannins »Phenolics

PSE 406 Lecture 126 “Other Extractives” lThese extractives are in the tree typically for reasons other than protection. »Fats and fatty acids »Proteins »Flavonoids »Sterols

PSE 406 Lecture 127 The Fragrance of a Tree lEach tree has a unique fragrance. »Some have strong fragrances than others like Cedar. »Some have only light odor. lThe aroma is due to volatile compounds produced by the tree (the odor chemicals become gases easily). lThese chemicals can be isolated and sold.

PSE 406 Lecture 128 General info lEnd use: »Pine pitch and resins (waterproof boats, in torches and binders). »Medicine, etc. lMonomers, dimers, polymers. lSoftwood have higher extractive content than hardwood. lMight be poplar (water) or non-polar solvent (toluene, ethanol, or ether) soluble. lMore extractives in bark compared to whitewood.

PSE 406 Lecture 129 Pitch Chemicals lWhen you grab a softwood tree and your hand sticks to the tree, you have discovered pitch. lPitch consists of about 50/50 terpenes and resin acids. Resin acids are glassy like chemicals also made of isoprene units.

PSE 406 Lecture 1210 Pitch as a Bandage lWhen a softwood tree is wounded, it releases pitch to “seal” the wound. »Terpenes serve as the antiseptic and then evaporate. »Resin acids serve as the bandage (and also as an antiseptic).

PSE 406 Lecture 1211 Sterols Role in Nature lSterols are found in plants as both free sterols, as sterol esters (of fatty acids) and as sterol glycosides lServe as components of membranes »Work with phospolipids to create membranes which are only permeable to certain chemicals lSterol esters »Believed to serve as transport agent to get sterols from site of biosynthesis to membrane

PSE 406 Lecture 1212 What are Fats and Oils? lFat and oils are energy storage material. lFats and oils are similar chemically: the difference is that fats are solids at room temperature and oils are liquids.

PSE 406 Lecture 1213 Chemical Composition of Fat/Oils lEsters of long chain fatty acids »Most often with glycerol lTrigylcerides, diglycerides, & monoglycerides lSimilar structures in all plants. What varies is the fatty acids attached to the glycerol and the percentage of tri, di, and monoglycerides H H H

PSE 406 Lecture 1214 Chemical Composition of Fatty Acids lFatty acids are long chained carboxylic acids »Mostly even numbered chains –16-18 carbons most common –20-22 less common »80% unsaturated: 1, 2 or 3 double bonds

PSE 406 Lecture 1215 Fat (Oil) Content lThere 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 lIn agricultural crops the majority of the oils are triglycerides.

PSE 406 Lecture 1216 Fats in Trees lFats are found in living cells - parenchyma »Very low content (1-2%) in oleoresin. »More present in sapwood than heartwood. »High content in many nuts. lFunction »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.

PSE 406 Lecture 1217 Waxes lWax 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 1218 Flavonoids lServe many roles in plants: »Protection »Coloration »Other unique roles.

PSE 406 Lecture 1219 Flavonoids Location in Tree lFound in the heartwood of most tress »Often responsible for coloration lFound in lesser amounts in the sapwood lAre found in large amounts in bark and roots lLeaves: green tea can contain up to 30% flavonoids lFlowers: color is often due to flavonoids

PSE 406 Lecture 1220 Flavonoids Medicinal Uses lHigher flavonoid content in diet reduces chance of: » Heart Disease –Strengthen capillaries –Dilates blood vessels »Stroke »Cancer: all types reduced –Finnish study = ½ rate of cancer

PSE 406 Lecture 1221 Condensed Tannins Biological Significance lWestern hemlock »Bark: 18% tannins, wood: 2% tannins »Chestnut and oak lProtection of plants against insects/animals »Bad Taste (bitter taste) lToxic to bacteria lUses of condensed tannins »Leather tanning: 10,000+ year old industry »Adhesives

PSE 406 Lecture 1222 Alkaloids lThese nitrogen containing compounds are found in a variety of different plants. »Located in the leaves, fruits, and bark. lYou are all aware of the alkaloids shown on this page you probably have never seen their structures. These are typically found in small amounts in plants but are worth large sums of cash. Nicotine Caffeine Cocaine