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Chapter 18 Amines and Amides

18.2Properties of Amines

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Boiling Points of Amines, Alcohols, and AlkanesThe boiling points of amines are higher than alkanes of similar mass lower than alcohols of similar mass

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Hydrogen Bonding in Amines

The polar N—H bond provides hydrogen bonding in 1° and 2° amines but

not 3° amines is not as polar as the —OH in alcohols

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Solubility in Water

Amines are soluble in water if they have 1 to 5 carbon

atoms because the N atom in

smaller amines forms hydrogen bonds with the polar O—H bond in water

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Learning Check

Consider the following compounds:

1) CH3—CH2—CH2—NH2

2) CH3—CH2—NH—CH3

3) CH3—CH2—CH2—CH3

A. Which compound has the highest boiling point?

B. Which compound(s) is (are) soluble in water?

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Solution

Consider the following compounds:

1) CH3—CH2—CH2—NH2

2) CH3—CH2—NH—CH3

3) CH3—CH2—CH2—CH3

A. Which compound has the highest boiling point?

1) CH3—CH2—CH2—NH2

B. Which compound(s) is(are) soluble in water?

1) CH3—CH2—CH2—NH2

2) CH3—CH2—NH—CH3

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Amines are Brønsted-Lowry bases that attract a H+ from H2O

to the N atom weak bases in water

Amines React as Bases

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An amine salt forms when an amine is neutralized

by an acid is named by replacing the amine

part of the name with ammonium followed by the name of the negative ion

Neutralization Forms Amine Salts

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Properties of Amine Salts

Amine salts are solids at room temperature soluble in water and body fluids the form used for drugs

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Cocaine

Cocaine is sold illegally as an amine salt is reacted with NaOH to produce the free amine form

known as “crack”

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Learning Check

Write the equation for ethylamine when it reacts witheach of the following:

A. H2O

B. HCl

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Solution

Write the equation for ethylamine when it reacts witheach of the following:

A.

B.