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Chapter 16 Carboxylic Acids and
Esters
16.1
Carboxylic Acids
Copyright © 2007 by Pearson Education, Inc.
Publishing as Benjamin Cummings
2
A carboxylic acid
Contains a carboxyl group, which is a carbonyl group (C=O)
attached to a hydroxyl group (—OH).
Has the carboxyl group on carbon 1.
carbonyl group
O
||
CH3 — C—OH hydroxyl group or CH3COOH
carboxyl group
Carboxylic Acids
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Models of Carboxylic Acids
The three-dimensional models show the geometry of atoms in
carboxylic acid molecules.
Copyright © 2007 by Pearson Education, Inc.
Publishing as Benjamin Cummings
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The IUPAC names of carboxylic acids
Replace the -e in the alkane name with -oic acid.
CH4 methane HCOOH methanoic acid
CH3—CH3 ethane CH3—COOH ethanoic acid
Number substituents from the carboxyl carbon 1.
CH3 O
| ║
CH3—CH—CH2—C—OH
4 3 2 1
3-methylbutanoic acid
IUPAC Names
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The common names of simple carboxylic acids
Are formic acid (1C), acetic acid (2C), propionic acid (3C), and
butyric acid (4C).
HCOOH formic acid
CH3—COOH acetic acid
Locate substituents using α, β, γ for the carbon atoms adjacent
to the carboxyl carbon.
CH3
γ β| α
CH3—CH—CH2—COOH
3-methylbutanoic acid (β-methylbutryic acid)
Common Names
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Alpha Hydroxy Acids
Alpha hydroxy acids
(AHAs)
Occur naturally in
fruit, milk, and
sugarcane.
Are used in skin care
products.
Copyright © 2007 by Pearson Education, Inc.
Publishing as Benjamin Cummings
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Names and Sources of Some
Carboxylic Acids
TABLE 16.1
Copyright © 2007 by Pearson Education, Inc.
Publishing as Benjamin Cummings
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Common Carboxylic Acids
Methanoic acid (formic acid)
O
║
H─C─OH
ethanoic acid (acetic acid)
O
║
CH3─C─OH
Copyright © 2007 by Pearson Education, Inc.
Publishing as Benjamin Cummings
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Aromatic Carboxylic Acids
Benzoic acid
Is the aromatic carboxylic acid.
Locates substituents by assigning 1 to the carbon attached to
the carboxyl group.
Has common names that assign prefixes ortho, meta, and para
for 2 substituents.
ortho 1, 2 location
meta 1, 3 location
para 1, 4 location
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Aromatic Carboxylic Acids
OHC
O
OHC
O
OHC
O
Cl
NH
2
benzoic acid 3-chlorobenzoic acid 4-aminobenzoic acid
m-chlorobenzoic acid p-aminobenzoic acid
[...]... acid 17 Chapter 16 Carboxylic Acids and Esters 16.2 Properties of Carboxylic Acids Copyright © 2007 by Pearson Education, Inc Publishing as Benjamin Cummings 18 Polarity of Carboxylic Acids Carboxylic acids Are strongly polar Have two polar groups: hydroxyl (−OH) and carbonyl (C=O) δ O ║δ + δ - + δ CH3CO H 19 Boiling Points of Carboxylic Acids The boiling points of carboxylic acids Are higher... in Water Carboxylic acids Water molecules Form hydrogen bonds with many water molecules With 1-4 carbon atoms are very soluble in water Copyright © 2007 by Pearson Education, Inc Publishing as Benjamin Cummings 22 Boiling Points and Solubility TABLE 16.2 Copyright © 2007 by Pearson Education, Inc Publishing as Benjamin Cummings 23 Acidity of Carboxylic Acids Carboxylic acids Are weak acids Ionize... Cummings 24 Acid Dissociation Constants Carboxylic acids TABLE 16.3 Have small Ka values Exist mostly as molecules and a few ions in aqueous solutions 25 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... Chapter 16 Carboxylic Acids and Esters 16.3 Esters 16.4 Naming Esters Copyright © 2007 by Pearson Education, Inc Publishing as Benjamin Cummings 29 Esters In an ester, The H in the carboxyl group is replaced with an alkyl group O || CH3 — C—O—CH3 ester group Copyright © 2007 by Pearson Education, Inc Publishing as Benjamin Cummings 30 Esterification Esterification is The reaction of a carboxylic. .. CH3─CH2─COOH propanoic acid (propionic acid) CH3 | B CH3─CH─CH2─COOH 3-methylbutanoic acid (β-methylbutyric acid) O C 3-bromobenzoic acid C OH (m-bromobenzoic acid) Br 14 Preparation of Carboxylic Acids Carboxylic acids can be prepared by oxidizing primary alcohols or aldehydes The oxidation of ethanol produces ethanoic acid (acetic acid) OH | [O] CH3—CH2 O || [O] CH3—C—H ethanol ethanal (ethyl alcohol)... reduce inflammation C OH O Is an ester of salicylic acid and acetic acid Oil of wintergreen O O C CH3 Is used to soothe sore muscles Is an ester of salicylic acid and methanol O C O CH3 OH 35 Esters in Plants Esters give flowers and TABLE 16.4 fruits their pleasant fragrances and flavors 36 Copyright © 2007 by Pearson Education, Inc Publishing as Benjamin Cummings ... Solution Write the equation for the reaction of propanoic acid and methanol in the presence of an acid catalyst O || CH3—CH2—C—OH + H—O—CH3 propanoic acid O H + methanol || CH3—CH2—C—O—CH3 + H2O 33 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 from alcohol from acid O methyl || CH3— O—C —CH3 ethanoate (acetate) . 1
Chapter 16 Carboxylic Acids and
Esters
16.1
Carboxylic Acids
Copyright © 2007 by Pearson Education, Inc.
Publishing as Benjamin Cummings
2
A carboxylic. of Carboxylic Acids
Chapter 16 Carboxylic Acids and
Esters
Copyright © 2007 by Pearson Education, Inc.
Publishing as Benjamin Cummings
19
Polarity of Carboxylic
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