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CHE 242 Unit VIII The Structure, Properties, Reactions and Mechanisms of Carboxylic Acids and Their Derivatives CHAPTER TWENTY-FIVE. Terrence P. Sherlock Burlington County College 2004. Examples of Lipids. =>. Waxes. Esters of long-chain fatty acids with long-chain alcohols.
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CHE 242Unit VIIIThe Structure, Properties, Reactions and Mechanisms of Carboxylic Acids and Their DerivativesCHAPTER TWENTY-FIVE Terrence P. Sherlock Burlington County College 2004
Examples of Lipids => Chapter 25
Waxes • Esters of long-chain fatty acids with long-chain alcohols. • Spermaceti is found in the head of the sperm whale and is probably used to control buoyancy. • Most natural waxes are protective coats for plants’ leaves, insects’ exoskeleton, mammals’ fur, and birds’ feathers. => Chapter 25
Triglycerides • Fatty acid esters of glycerol. • Fats • Solid at room temperature • Most are derived from mammals • Oils • Liquid at room temperature • Most are derived from plants or cold-blooded animals. => Chapter 25
Fatty Acids • Unbranched carboxylic acids with 12-20 carbons. • Most contain an even number of carbons because they are built from acetic acid units. • Melting points increase with increasing molecular weights. • Unsaturation greatly lowers the melting point. => Chapter 25
=> Melting Points • A cis double bond bends the molecule so it cannot pack efficiently. • A trans double bond has less effect. Chapter 25
=> Fats and Oils • Most fats have saturated fatty acids. • Most oils have unsaturated fatty acids. Chapter 25
=> A soap Saponification • “Soap-making” • Base-catalyzed hydrolysis of ester linkages in fats and oils. Chapter 25
Soap Structure => Chapter 25
Grease in Soap Solution => Chapter 25
Detergents => Chapter 25
Steroids • Polycyclic, usually all trans. • Common structural features: • =O or -OH at C3 • Side chain at C17 • Double bond from C5 to either C4 or C6. => Chapter 25
=> A-B Ring Junction May be cis, but usually is trans. Chapter 25
Cholesterol • Common biological intermediate. • Probably a precursor to other steroids. • Side chain at C17 and double bond C5-C6. => Chapter 25
Sex Hormones • Female hormone has an aromatic ring and one less methyl group than the male hormone. • Testosterone is converted to estradiol in the ovaries. => Chapter 25
POWER POINT IMAGES FROM “ORGANIC CHEMISTRY, 5TH EDITION”L.G. WADEALL MATERIALS USED WITH PERMISSION OF AUTHORPRESENTATION ADAPTED FOR BURLINGTON COUNTY COLLEGEORGANIC CHEMISTRY COURSEBY:ANNALICIA POEHLER STEFANIE LAYMAN CALY MARTIN Chapter 25