ANDREW O. BAAFI
Organic Chemistry I Lab.
Instructor: Dr. Strange
Preparation of Isopentyl Acetate (isoamyl acetate) / Gas Chromatography (Esterification).
Fischer, W. H., A. G. Craig. “Microscale Esterification of Peptides and Analysis by MALDI-MS.” http://www.salk.edu/LABS/pbl/brukeran1.htm. 10-02-2001
Mayo, Dana W, Pike Ronald M, Trumper PeterK. Microscale Organic Laboratory. 3rd ed. New York: Wiley & Sons, 1994.
Strange De Soria, Louise. Chemistry 2641 Laboratory Survival Guide. Atlanta: Dekalb College Central Campus Science Department, 2001.
PURPOSE: The purpose of this experiment is to use isopentyl alcohol and acetic acid to produce an ester (ethyl laurate).
Esters are among the most widespread of all naturallyoccurring compounds. Many simple esters are pleasant-smelling liquids that are responsible for the fragrant odors of fruits and flowers. Examples are methyl butanoate, which is find in pineapple oil, and isopentyl acetate, which is a constituent of banana oil. The ester linkage is also present in animal fats and in many biologically important molecules.
Esters can be formed from both organic andinorganic acids and the process of producing an ester is called an Esterification. Esters of organic acids are usually colorless, neutral liquids, pleasant-smelling and generally insoluble in water but readily soluble in organic solvents. Esters are prepared synthetically in large quantities for commercial use as artificial fruit essences and other flavorings and as components of perfumes.Esterification is used to derivatize carboxylic acids and other acidic functional groups. In a typical reaction, Esterification involves the condensation of the carboxyl group of an acid and the hydroxyl group of an alcohol, with the elimination of water. Many Esterification reactions are slow and elevated temperatures are frequently used. Since the Esterification reaction is an equilibrium reaction, itmay be necessary to remove the water generated during the reaction.
The chemical industry uses esters for a variety of purposes. Ethyl acetate, for example, is a common solvent found in nail-polish remover, and dialkyl phthalates are used as plasticizers to keep polymers from becoming brittle. They also have important medical uses. Ethyl nitrite is a diuretic and an antipyretic. Amyl nitriteis used in the treatment of asthma and epileptic convulsions as an antispasmodic.
Of all the esters been discuss, the production of isopentyl acetate by using the Fischer Esterification reaction is our main concern now.
Mechanism of the Fischer Esterification Reaction
R —C— + H R—C
+ö R R
(( ( (
Ŕ— :O: + R — CŔ— +ö —C— (ÖH ŔÖ(—C— (ÖH
( ( ( ( (
H (ÖH H (ÖH H—+ö
H3O+ + Ŕ — (Ö — C Ŕ — (Ö —C + H2O