The Foundations of Chemistry

Many experiments have shown
conclusively that the OH group from
the acid and the H from the alcohol
are the atoms that form water
molecules.

1124 CHAPTER 28: Organic Chemistry II: Shapes, Selected Reactions, and Biopolymers

In general terms, the reaction of an organic acid and an alcohol may be represented as

(R and Rmay be the same or different groups.)

Reactions between acids and alcohols are usually quite slow and require prolonged

boiling (refluxing). The reactions between most acyl halides and most alcohols, however,

occur very rapidly without requiring the presence of an acid catalyst.

Amides are usually notprepared by the reaction of an amine with an organic acid. Acyl

halides react readily with primary and secondary amines to produce amides. The reaction

of an acyl halide with a primary or secondary amine produces an amide and a salt of the

amine.

HYDROLYSIS OF ESTERS

Because most esters are not very reactive, strong reagents are required for their reactions.

Esters can be hydrolyzed by refluxing with solutions of strong bases.

The hydrolysis of esters in the presence of strong bases is called saponification(soap-

making).

In general terms, the hydrolysis of esters may be represented as

NaOH R C 

O

RRC   ONa ROH

O

O

ester salt of an acid alcohol

heat

CH 3 C CH 2 CH 3 NaOH CH 3 CH 2 OH

O

O CH 3 C

O

ONa

ethyl acetate sodium acetate ethanol

heat

28-7

2CH 3 NH 2 CH 3 C Cl CH 3 NH 3 Cl

O

CH 3

CH 3

CN

O H

methylamine

(a primary amine)

acetyl chloride

(an acyl halide)

N-methylacetamide

(an amide)

methylammonium

chloride (a salt)

C

O

CH 3 Cl CH 3 CH 2 OH CH 3 C CH 2 CH 3

O

O HCl

acetyl chloride ethyl alcohol ethyl acetate

C

O

R OH R  OH R C

O

OHR 2 O

acid alcohol ester

C

O

CH 3 OH CH 3 CH 2 OH CH 3 C

O

OHCH 2 CH 3  2 O

acetic acid ethyl alcohol ethyl acetate, an ester

H, heat

In this preparation, one half of the
amine is converted to an amide and
the other half to a salt.

Tripalmitin, a triglyceride.