The method of ester formation used is the reaction of carboxylic acids and alcohols catalysed by a strong acid. The reaction forms an equilibrium which will contain a mixture of the reactants and products. For example when one mole of acetic acid is mixed with 1 mole of ethyl alcohol, 2/3 of a mole of ester and 2/3 of a mole of water is produced while 1/3 of a mole of each reactant maintains unchanged. Yields of equilibrium reactions can be manipulated in a number of ways; for example, if a dehydrating agent is present, such as sulfuric acid, the result is a shift in the equilibrium to keep water within an acceptable level. The yield is also influenced by the concentrations of each reactant and product.
The formation of multiple esters through reactions between various alcohols and carboxylic acids, each ester should have its own identifiable unique scent.
Glass Droppers (one for each chemical)
Test Tubes (8)
Test Tube Holder
500 ml beaker
250 ml beaker
(note: These chemicals are extremely flammable)
1. Bring about 300ml of water to a boil, using the hot plate and 500ml beaker.
2. After water boils, turn off hot plate.
3. Place about ten drops of one of the carboxylic acids into a test tube.
4. Add ten drops of an alcohol, as well as two drops of sulfuric acid (Catalyst and Dehydrating agent).
5. Gently swirl the contents of the test tube.
6. cover the top of the tube.
7. Place test tube in hot water bath for approximately 15 minutes.
8. Put about 100ml of water into the 250ml beaker.
9. Empty contents of test tube into the 250ml beaker.
10. Swirl the mixture and waft vapors towards nose.
11. note the odor of the ester
12. Repeat steps 3-11 for each combination of carboxylic acid and alcohol.
Methods to increase the yields of the products include an increase in the concentration or molarity of the reactants.