Chapter 14: Carboxylic Acids, Esters, Amines, and Amides

Carboxylic Acids

Carboxylic Acids

These are weak acids. They have a sour or tart taste, produce hydronium ions in water, and neutralize bases.

carboxyl group

The carbon atom of a carbonyl group is attached to a hydroxyl group that forms a ______.

negatively charged

When a carboxylic acid ionizes in water, a hydrogen ion is transferred to a water molecule to form a ________ carboxylate ion and a hydronium ion.

neutralized

Because carboxylic acids are weak acids, they are completely ______ by strong bases.

ester

In an _____, the —H of the carboxylic acid is replaced by an alkyl group

Esterification

An ester is produced when a carboxylic acid and an alcohol react in the presence of an acid catalyst ad heat.

Acid Hydrolysis

• It occurs when esters are heated with water in the presence of a strong acid.

• Water reacts with the ester to form a carboxylic acid and an alcohol.

• It is the reverse of the esterification reaction.

Base Hydrolysis

• It is also known as saponification.

• When an ester undergoes hydrolysis with a strong base, the products are the carboxylate salt and the corresponding alcohol.

Saponification

Refers to the reaction of an ester of a long-chain fatty acid with NaOH to make soap.

Amines

These are derivatives of ammonia in which one or more hydrogen atoms are replaced with alkyl or aromatic groups.

methylamine

In ______, a methyl group replaces one hydrogen atom in ammonia.

dimethylamine

The bonding of two methyl groups gives _____.

trimethylamine

The bonding of three methyl groups in _____ replaces all the hydrogen atoms in ammonia.

primary (1°) amine

In a _____, the nitrogen atom is bonded to one alkyl group.

secondary (2°) amine

In a _____, the nitrogen atom is bonded to two alkyl groups.

tertiary (3°) amine

In a _____, the nitrogen atom is bonded to three alkyl groups.

N—H bond

Because amines contain a polar ____, they form hydrogen bonds with water.

primary (1°) amine

In a ____, —NH2 can form more hydrogen bonds than the secondary (2°) amine.

tertiary (3°) amine

In a _____, which has no hydrogen on the nitrogen atom, can form only hydrogen bonds with water from the N atom in the amine to the H of a water molecule.

Brønsted–Lowry base

Ammonia acts as a _______ because it accepts H+ from water to produce an ammonium ion and a hydroxide ion.

ammonium salt

In a neutralization reaction, an amine acts as a base and reacts with an acid to form an _____.

Ammonium salts

• These are ionic compounds with strong attractions between the positively charged ammonium ion and an anion, usually chloride.

• These salts are solids at room temperature, odorless and soluble in water and body fluids.

Heterocyclic amine

• A cyclic compound that contains one or more nitrogen atoms in the ring.

• The rings typically consist of five or six atoms and one or more nitrogen atoms.

Pyrrolidine

A ring of four carbon atoms and a nitrogen atom, all with single bonds.

Piperidine

A six-atom heterocyclic ring with a nitrogen atom.

Amides

These are derivatives of carboxylic acids in which a nitrogen group replaces the hydroxyl group.

Amidation

A reaction where an amide is produced, in which a carboxylic acid reacts with ammonia or a primary or secondary amine.

hydrolysis

Amides undergo _______ when water is added to the amide bond to split the molecule.

acid

When an ____ is used, the hydrolysis products of an amide are the carboxylic acid and the ammonium salt.

base

In _____ hydrolysis, the amide produces the carboxylate salt and ammonia or an amine.