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Chapter 14 Carboxylic Acids, Esters, Amines, and Amides 14.1 Carboxylic Acids 1 A poem by Ogden Nash The ant has made himself illustrious Through constant industry industrious So what? Would you be calm and placid If you were full of formic acid? Carboxylic Acids A carboxylic acid contains a carboxyl group, which • is a carbonyl group (C=O) attached to a hydroxyl group (—OH). • is found on carbon 1 in carboxylic acids. O CH3 C OH hydroxyl group or CH3COOH carbonyl group 3 IUPAC Names In the IUPAC names of carboxylic acids • the -e in the alkane name is replaced with -oic acid. CH4 Methane CH3—CH3 Ethane HCOOH Methanoic acid CH3—COOH Ethanoic acid • substituents are numbered from the carboxyl carbon 1. O CH3 CH3 4 CH 3 CH2 2 C 1 OH 3-methylbutanoic acid 4 CH 110 homework #11 due this th Friday – Nov. 20 CH 110 homework #12 due next Wednesday – Nov. 25th Names and Sources of Some Carboxylic Acids 6 Common Names for Acids HCOOH CH3COOH CH3CH2COOH CH3(CH2)2COOH CH3(CH2)3COOH CH3(CH2)4COOH CH3(CH2)5COOH CH3(CH2)6COOH Formic Acetic Propionic Butyric Valeric Caproic Enanthic Caprylic http://en.wikipedia.org/wiki/Carboxylic_acid Formica (ant) Acetum (sour) Pro (first) + Pion (fat) Butyrum (butter) Valere (strong) Caper (goat) Vine (wine) Caper (goat) Common Carboxylic Acids methanoic acid (formic acid) O H C OH ethanoic acid (acetic acid) O CH3 C OH 8 Nail Fungus Treatment by NonyX Nail Gel - End Yellow Nails Price: $23.95 Vendor: Brand: Xenna Corp Availability: In Stock-Ships in 24 Hours Product Description Discolored Fingernails or Toenails? Just like a superhero, NonyX® Nail Gel clears out the keratin debris that causes the problem. If your toenails or fingernails look dark or yellow they may need NonyX Nail Gel. NonyX Gel contains naturally-derived ethanoic acid to remove keratin debris buildup from under the nail. With regular use, your nails are clear and healthy-looking – or your money back. Diabetic-friendly NonyX Nail gel is used by podiatrists and can be found in the footcare aisle of your favorite pharmacy or mass retail store. Detailed Description: * Contains patented, naturally-derived ethanoic acid * Topical * Effective * Clear and easy-to-use * All natural * Money-back guarantee * Diabetic-friendly * One 4 oz. bottle is a 2-3 month supply * Made in the USA * NOT TESTED ON ANIMALS FAQ Q: What are the ingredients? A: Deionized Water, Ethanoic Acid, Xanthan Gum, Fragrance 9 Aromatic Carboxylic Acids Benzoic acid • is the aromatic carboxylic acid. • locates substituents by numbering the ring from carbon 1 in the carboxyl group. 3,4-Dichlorobenzoic Acid Benzoic Acid Para-Aminobenzoic Acid 10 Chapter 14 Carboxylic Acids, Esters, Amines, and Amides 14.2 Properties of Carboxylic Acids 11 Polarity of Carboxylic Acids Carboxylic acids • are strongly polar. • have two polar groups: hydroxyl (−OH) and carbonyl (C=O). 12 Comparison of Boiling Points Compound Molar Mass Boiling Point O CH3 CH3 CH2 CH2 C CH2 H OH 58 49 °C 60 97 °C 60 118 °C O CH3 C OH 13 Solubility in Water Carboxylic acids: • form hydrogen bonds with many water molecules. Water molecules • with 1-4 carbon atoms are very soluble in water. 14 Acidity of Carboxylic Acids Carboxylic acids • are weak acids. • ionize in water to produce carboxylate ions and hydronium ions. O CH3 C O OH + H2O CH3 C O- + H3O+ 15 Neutralization of Carboxylic Acids Carboxylic acid salts • are a product of the neutralization of a carboxylic acid with a strong base. CH3—COOH + NaOH CH3—COO– Na+ + H2O acetic acid sodium acetate (carboxylic acid salt) • are used as preservatives and flavor enhancers. 16 Monosodium glutamate (MSG, also known as sodium glutamate) 17 Chapter 14 Carboxylic Acids, Esters, Amines, and Amides 14.3 Esters 18 Esters In an ester, the H in the carboxyl group is replaced with an alkyl group. O CH3 C O CH3 ester group 19 Esterification Esterification is the reaction of • a carboxylic acid and alcohol in the presence of an acid catalyst to produce an ester. O CH3 C OH + H O O CH2 CH2 CH3 H+ O CH3 C CH3 + H2O Ethyl acetate (an ester) 20 Ester Products Aspirin • is used to relieve pain and reduce inflammation. • is an ester of salicylic acid and acetic acid. Oil of wintergreen • is used to soothe sore muscles. • is an ester of salicylic acid and methanol. O C OH O O C CH3 O C O CH3 OH 21 Naming Esters The name of an ester contains the names of • the alkyl group from the alcohol. • the carbon chain from the acid with –ate ending. methyl ethanoate (acetate) O CH3 O C CH3 IUPAC: methyl ethanoate common: methyl acetate 22 Naming Esters Esters are named • with the alkyl group of the alcohol, • and the salt (-ate) of the carboxylic acid From methanol (methyl alcohol) From ethanoic acid (acetic acid) Methyl ethanoate (methyl acetate) 23 Esters in Plants Esters give pleasant fragrances and flavors to many fruits and flowers. 24 Acid Hydrolysis of Esters In acid hydrolysis • an ester reacts with water to produce a carboxylic acid and an alcohol. • an acid catalyst is required. O H+ H—C—O—CH2—CH3 + H2O O H—C—OH + H—O—CH2—CH3 25 Base Hydrolysis (Saponification) Base hydrolysis or saponification, • is the reaction of an ester with a strong base. • produces the salt of the carboxylic acid and an alcohol. O || CH3—C—O—CH2—CH3 + NaOH O CH3—C—O– Na+ + HO—CH2—CH3 salt of carboxylic acid alcohol 26 Base Hydrolysis of Fatty Acids Produces Soaps 27 Cleaning Action of Soap A soap • contains a nonpolar end that dissolves in nonpolar fats and oils, and a polar end that dissolves in water. • forms groups of soap molecules called micelles that dissolve in water and are washed away. 28 Chapter 14 Carboxylic Acids, Esters, Amines, and Amides 14.4 Amines 29 Amines Amines • are derivatives of ammonia, NH3. • contain N attached to one or more alkyl or aromatic groups. CH3 CH3 NH2 CH3 NH NH2 CH3 CH3 N CH3 30 Naming Amines Simple amines • are named as alkylamines. • list the names of the alkyl groups bonded to the N atom in alphabetical order in front of amine. CH3—CH2—NH2 Ethylamine CH3—NH—CH3 CH3 | CH3—N—CH2—CH3 Dimethylamine Ethyldimethylamine 31 Do You ? N Know What Aromatic Amines • The amine of benzene is named aniline. • Alkyl groups on the N use the prefix N- with alkyl name. NH2 NH2 NH CH3 Cl aniline 3-chloroaniline meta-chloroaniline N-methylaniline 33 Hydrogen Bonding for Amines The N−H bond • provides hydrogen bonding in 1°and 2° amines, but not in 3° amines. • is not as polar as the O-H bonds in alcohols. 34 Solubility in Water Amines • with 1-6 carbon atoms are soluble in water. • form hydrogen bonds with the polar O-H bond in water. Copyright © 2009 by Pearson Education, Inc. 35 Amines React as Bases Like ammonia, amines are weak bases in water. NH3 + H2O NH4+ + OH– ammonium hydroxide CH3—NH2 + H2O CH3—NH3+ + OH– methylammonium hydroxide 36 Neutralization Forms Amine Salts An amine salt • forms when an amine is neutralized by acid. • is named by replacing the amine part of the name with ammonium, followed by the name of the negative ion. CH3—NH2 + HCl CH3—NH3+ Cl– methylamine methylammonium chloride 37 Properties of Amine Salts Amine salts are • solids at room temperature. • soluble in water and body fluids. • the form used for drugs. Ephedrine hydrochloride Ephedrine HCl Sudafed Diphenhydramine hydrochloride Diphenhydramine HCl Benadryl 38 Alkaloids Alkaloids are • physiologically active nitrogencontaining compounds. • obtained from plants. • used as anesthetics, antidepressants, and in stimulants such as caffeine. • often addictive. 39 Cocaine Cocaine (from coca leaves ) is • sold illegally as the amine salt. • reacted with NaOH to produce the free amine form known as “crack.” Cocaine hydrochloride Cocaine (free base) 40 Caffeine Caffeine • is a stimulant of the central nervous system. • is found in coffee beans, tea, chocolate, and soft drinks. Caffeine 41 Nicotine Nicotine • increases the adrenaline level in the blood. • causes addiction to tobacco. N CH 3 42 Morphine and Codeine Morphine and codeine are • alkaloids. • obtained from the oriental poppy plant. • used as painkillers. • modified to make heroin. Morphine Codeine 43 Chapter 14 Carboxylic Acids, Esters, Amines, and Amides 14.5 Amides 44 Amides In amides, • an amino group(–NH2) replaces the –OH group of carboxylic acids. O CH3 C O OH CH3 C NH2 45 Aromatic Amide The aromatic amine is benzamide. O C NH2 Benzamide 46 Some Amides in Health and Medicine • Urea is the end product of protein metabolism. • Saccharin is an artificial sweetener. • Some amides such as phenobarbital, NembutalTM and SeconalTM are barbiturates. • Acetaminophen is used to reduce fever and pain. 47 Some Amides in Health and Medicine 48 Physical Properties of Amides Amides • that are primary (−NH2) or secondary (−NH−) form hydrogen bonds. • that are primary have higher melting points than secondary. • that are tertiary (no H on N) do not form hydrogen bonds and have lower melting points. • all form hydrogen bonds with water. • with 1-5 carbon atoms are soluble in water. 49 Hydrogen Bonding of Amides O || CH3—C—N—H | H Hydrogen bonding occurs between primary amides. O || CH3—C—N—H | H 50