Experiment 7: Esterification

Organic Compounds

• Primarily composed of carbon and hydrogen atoms along with heteroatoms such as oxygen, nitrogen, sulfur, and the halogens.

Functional Groups

• Because of the vast number of organic compounds that exist in nature and that can be synthesized in the laboratory, they are placed in classes called _____ depending on the structural features present in the molecules.

• Hydroxyl (OH) Group

• Carboxyl (COOH) Group

• Ester

• Some example of organic compounds and their functional groups are alcohols which contain a _____, and carboxylic acids which contain a _____. When these two types of organic compounds react, they form an _____.

Esters

• Structurally characterized by the presence of a carbonyl group with an alkoxy group attached to the carbonyl carbon.

• Volatile substances that have lower boiling points than alcohols and carboxylic acids.

• Both compounds occur naturally and are synthesized in the laboratory as scents of flowers and fruits.

• Acid Catalyst

• Fischer Esterification

• In the laboratory, esters can be synthesized from an alcohol and a carboxylic acid in the presence of an _____ and heat through the process of _____.

Phenolphthalein

• In this experiment, esters will be synthesized in test tubes from different alcohols and carboxylic acids and characterized with a simple, chemical test involving _____, a common acid-base indicator.

• Synthesize esters from alcohols and carboxylic acids;

• Describe the conditions required for the synthesis and hydrolysis of esters;

• Observe the changes in the physical and chemical properties of alcohols, carboxylic acids, as they are combined into esters; and

• Distinguish alcohols, carboxylic acids, and esters based on their physical, chemical, and structural properties

• Objectives of the experiment.

1. Isoamyl Alcohol (Isopentyl Alcohol)             

2. Ethanol

3. Methanol                                                

4. Glacial Acetic Acid

5. Benzoic Acid                                            

6. Salicylic Acid

7. Concentrated sulfuric acid                         

8. Sodium hydroxide

9. Phenolphthalein

• 9 reagents used.

• Hot Water Bath

• 250 mL

• Procedure 1.

• Prepare a _____ by filling up a _____ beaker halfway with tap water and placing it on top of a stove. Set the stove to low setting once the water is hot.

• Waft

• Smell

• 10

• 10 or a Pinch

• Carboxylic Acid

• Procedure 2.

• Before mixing the alcohol and the carboxylic acid, try to _____ and take note of their individual _____.

• Add _____ drops of alcohol and _____ drops (if liquid) or a _____ (if solid) of _____ into a test tube.

• Isoamyl Alcohol

• Glacial Acetic Acid

• Test tube A.

• 10 drops of _____

• 10 drops of _____.

• Ethanol

• Glacial Acetic Acid

• Test tube B.

• 10 drops of _____.

• 10 drops of _____.

• Methanol

• Salicylic Acid

• Test tube C.

• Approximately 25 drops of _____, enough to dissolve acid.

• Pea size of _____.

• Ethanol

• Salicylic Acid

• Test tube D.

• 10 drops of _____.

• Pea size of _____.

• 2

• Concentrated Sulfuric Acid

• Procedure 3.

• Add _____ drops of _____ into the test tube with the alcohol and carboxylic acid.

• 10 minutes

• Scent

• Evaporating

• Wafting

• Procedure 4.

• Place the test tube into the hot water bath for _____ or until a _____ is detected coming from the test tube. Avoid _____ the solution. You can start observing the scent by _____. Do not directly smell from the solution.

• 100 mL

• Appearance

• Procedure 5.

• Transfer the test tube into a _____ beaker filled halfway with tap water to cool down. Observe any changes in the _____ of the contents of the test tube.

Waft

• Procedure 6.

• After cooling, carefully _____ the scent coming out of the test tube and describe the scent.

• 5

• Sodium Hydroxide

• 2

• Phenolphthalein Indicator

• Procedure 1 in characterization.

• Add _____ drops of _____ into test tube C followed by _____ drops of _____. Take note of any changes.

• Hot Water Bath

• 10 minutes

• Procedure 2 in characterization.

• Place the test tube back into the _____ for _____ or until changes are observed.  Take note of your observations.