Comparison of Three Isomers of Butanol

Comparison of Three Isomers of Butanol

Lab #3 – Comparison of Three Isomers of Butanol
Ref: Textbook            

Purpose:

To observe and compare the reactivity’s of three alcohols as examples of 1°, 2°, 3° alcohols.

Apparatus:

Safety goggles
1-butanol
2-butanol
2-methyl-2-propanol
HCl (aq) (12 mol. L-1)
3 test tubes
Test tube rack
Pipettes
KMnO4 solution (0.01 mol.L -1)

Background Discussion:

Primary Alcohol (1°)
- OH is bonded to a carbon, bonded to only one other carbon.
(eg. 1-butanol)
Secondary Alcohol (2°)
- OH is bonded to a carbon bonded to two other carbons.
(eg. 2-butanol)

Tertiary Alcohol (3°)
- OH is bonded to a carbon bonded to three other carbons.
(eg. 2-methyl-2-propanol)
Oxidizing Agent
MnO4– (aq) Purple
MnO4 2- (aq) Green
MnO2 (s) Yellow/Brown
Mn 2+ Rose


Safety:

1. Alcohols are volatile and flammable. Avoid exposure and use a rubber stopper in test tubes to avoid breathing unnecessary fumes.

2. 12 mol.l-1 HCl(aq) is an extremely corrosive volatile chemical. Avoid exposure by transferring in a fume hood. Upon exposure, rinse under water.



3. MnO4- (aq) oxidizes skin, forming a semi-permanent brown/black stain. Although this is more of a cosmetic issue than a safety precaution, do not touch face and if exposure occurs, rinse under water immediately.

Procedure:

Ref: “Comparison of Three Isomers of Butanol” (Textbook pg. 84 Investigation: 1.5.1)

Note changes:

Part 1) (Using HCl(aq))

- 4 drops of each alcohol per test tube (stopper the test tube)
- 20 drops of HCl(aq) per test tube
- Transfer in fume hood
- Dispose of chemicals in fume hood

Part 2) (Using KMnO4(aq) )

- 8 drops of each alcohol per test tube (stopper)
- 40 drops of KMnO4(aq) per test tube
- Dispose in fume hood

Observations:

Exp. #1: Using HCl(aq)

Alcohol Relative Cloudiness Time taken to reach state of cloudiness (secs)
1-butanol Not cloudy 120
2-butanol Slightly cloudy 60...