Organic Chemistry Assignment

© Professors Kathleen V. Kilway and Andrea Drew, Department of Chemistry, University of Missouri – Kansas City, 2007 – CHEM 322L

10.

M. Jones:

Fisher Esterification: Preparation

of Banana Oil

Reactions of Esters: Addition - Elimination, Chapter 19.7, pgs 1049-1058

Fischer Esterification, Figures 19.32 and 19.33, pgs 1049-1050

This procedure has been adapted from the microscale procedure described in the third edition of

Macroscale and Microscale Organic Experiments by Kenneth L. Williamson (Houghton Mifflin,

Boston, 1999).

Background

Esters. Esters have the structure of -COOR. Instead of the alcohol portion of the

carboxylic acid (-COOH), there is an ether portion. The low boiling, volatile

esters are known for their "fruity" smell and flavor. They are used in artificial

flavorings. Some typical esters, which are used as artificial flavors are listed in

the table below (Operational Organic Chemistry, John W. Lehman, Third

Edition, Prentice Hall, 1999). The "taste" of a candy or food is a special science,

food chemistry. It is an art to create are combinations of different flavorings that

imitate a "natural" flavor.

Table 1.

Name

Flavor

1- propyl acetate

CH3CO2CH2CH2CH3

pear

octyl acetate

CH3CO2(CH2)7CH3

oranges

isopentyl acetate

CH3CO2CH2CH=C(CH3)2

"Juicy-Fruit"

isopentyl acetate

CH3CO2CH2CH2CH(CH3)2

banana

isobutyl propionate

CH3CH2CO2CH2CH(CH3)2

rum

ethyl butyrate

CHEM 322L

Structure

CH3CH2CH2CO2CH2CH3

pineapples

Experiment 10: Preparation of Banana Oil 1

In this experiment, you will be performing a Fischer esterification. The general

mechanism is pictured in Figure 1.

O

O

ROH2

R

O

H

R

ROH

O

R

Figure 1. The overall reaction for Fischer esterification.

The overall mechanism for a general acid and alcohol is depicted in Figure 2.

H

H

O

O

P ROH2

R

O

H

OR

H

O

ROH

O

L

R

OH

R

H

H

H

OH

OR...