by Fisher Esterification
Esters compose an important class of organic compounds. Esters often have a pleasant scent and are found in natural fragrances. Esters can be prepared synthetically for use in foods, flavorings, and perfumes. Ethyl acetate is often used as a primary solvent in non-acetone fingernail polish remover.
Figure 1 The synthesis of ethyl acetate
The esterification process produces esters through a condensation reaction. Condensation reactions have water as one of the products. The starting compounds for esters are an alcohol and an acid (either an organic or an inorganic acid). A catalyst, such as concentrated acid or an ion-exchange resin, is added to accelerate the reaction. This reaction will not go to completion, but instead reaches equilibrium after a given amount of time. Using Le Chatelier’s Principle, the equilibrium can be shifted toward the product by adding more reactants or removing products.
Although the esterification reaction produces water as a product, the mechanism is not an acid-base neutralization reaction. The esters are named as salts of the acids prefaced with the name of the alcohol. Examples are shown in the chart below.
|Alcohol |Acid |Ester |Odor | |methyl |acetic |methyl acetate |sweet | |ethyl |acetic |ethyl acetate |fruity | |isoamyl |acetic |isoamyl acetate |banana | |isoamyl |butyric |isoamyl butyrate |pear |
In this experiment you will conduct the reaction between ethyl alcohol and acetic acid. You will use a Vernier Mini GC to follow and confirm the production of the ester, ethyl acetate.
IN THIS EXPERIMENT, YOU WILL
* Conduct an esterification reaction to produce ethyl acetate. * Measure and analyze the GC retention times of the reactants and products involved in synthesizing ethyl acetate. * Measure and analyze the GC retention times of the reaction mixture to confirm the production of ethyl acetate.
|LABQUEST OR COMPUTER |GLACIAL ACETIC ACID | |LABQUEST APP OR LOGGER PRO |ETHANOL, DENATURED | |VERNIER MINI GC |ETHYL ACETATE | |TEMPERATURE PROBE |DOWEX 50(2 ION EXCHANGE RESIN | |1 (L GLASS SYRINGE |ACETONE | |PLASTIC BERAL PIPETS |KIMWIPES® OR PAPER TOWELS | |THREE TEST TUBES, 25(200 MM |PARAFILM® OR CORK STOPPERS FOR TEST TUBES | |TEST TUBE RACK |HOT PLATE | |TEST TUBE CLAMP |ICE BATH | |TWO 250 ML BEAKERS | |
PART I DETERMINE THE GC RETENTION TIMES FOR THE INDIVIDUAL REACTANTS AND PRODUCTS
1.Obtain and wear goggles. Protect your arms and hands by wearing a long-sleeve lab coat and gloves. Conduct...