Chapter 14 Lecture slides (carboxylic acids, esters, amides, and amines)

Chapter Overview

• Title: Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition

• Focus: Carboxylic Acids, Esters, Amines, and Amides

Carboxylic Acids

Definition

• Contain a carboxyl group (-COOH), with:

  • Hydroxyl group (-OH)

  • Carbonyl group (C=O)

IUPAC Naming

• The -e in the alkane name is replaced with -oic acid:

  • Example: CH4 (Methane) becomes Methanoic acid

• Substituents are numbered starting from the carbon of the carboxyl group (carbon 1).

  • Example: 3-Methylbutanoic acid

  • Example: 2,3-Dichlorobenzoic acid

Common Carboxylic Acids

• Formic Acid: Found in ant stings, causes skin irritation.

• Ethanoic Acid (Acetic Acid): Provides the sour taste of vinegar.

Polarity and Solubility

• Carboxylic acids are strongly polar due to:

  • Hydroxyl group (-OH)

  • Carbonyl group (C=O)

• Form hydrogen bonds with water; soluble if 1 to 4 carbon atoms.

• Solubility decreases with increasing carbon chain length.

Carboxylic Acid Salts

• Ionic compounds with strong attractive forces between ions.

• Properties:

  • Solids at room temperature

  • High melting points

  • Usually soluble in water

Esters

Definition

• Formed from the reaction of carboxylic acids and alcohols.

• Found in fats and oils.

• Contribute to the aroma and flavor of fruits like bananas and oranges.

Esterification Process

• Reaction involves a carboxylic acid and alcohol with:

  • Acid catalyst

  • Heat

• Hydrogen in the carboxylic acid's -OH group is replaced by an alkyl group from the alcohol.

Naming Esters

• Composed of two parts:

  1. Alkyl part from the alcohol

  2. Carboxylate name of the carboxylic acid

Amines

Definition

• Derivatives of ammonia (NH3) where one or more hydrogen atoms are replaced with alkyl or aromatic groups.

• Examples:

  • CH3—CH2—CH2—N—CH3

  • H—N—CH2—CH3

Classification of Amines

• Primary (1°): One carbon group bonded to nitrogen.

• Secondary (2°): Two carbon groups bonded to nitrogen.

• Tertiary (3°): Three carbon groups bonded to nitrogen.

Naming Amines

• Named as alkylamines, with alkyl groups in alphabetical order preceding "amine."

• Examples:

  • Ethylamine

  • Dimethylamine

  • Ethyldimethylamine

Solubility of Amines

• Due to polar N—H bonds, amines can form hydrogen bonds with water.

• Primary amines can form more hydrogen bonds than secondary.

• Tertiary amines have no hydrogen on nitrogen and rely on the N atom for hydrogen bonding.

• Larger amines (over six carbons) exhibit decreased solubility due to hydrocarbon chains.

Amides

Definition

• Derivatives of carboxylic acids, where the hydroxyl (-OH) group is replaced by a nitrogen group (-NH2).

Preparation of Amides

• Produced by reacting carboxylic acid with ammonia or primary/secondary amines, requiring heat.

Naming Amides

• Named by replacing "oic acid" or "ic acid" from the carboxylic acid name with "amide."

• Any alkyl groups attached to nitrogen are prefixed with "N-."

Hydrolysis of Amides

• Acid Hydrolysis: Produces carboxylic acid and ammonium salt.

• Base Hydrolysis (Alkaline Hydrolysis): Produces the salt of a carboxylic acid and an amine or ammonia.