3 reactions of isomers

Purpose

To test the reactions of primary, secondary, and tertiary alcohols with acid and with an oxidizing agent.

Materials

chemical safety goggles lab apron protective gloves test-tube rack eyedropper dropper bottles containing butan-1-ol butan-2-ol
2-methylpropan-2-ol
potassium permanganate solution, KMnO4 (aq) (0.01 mol/L) concentrated hydrochloric acid, HCl (aq) (12 mol/L) (for teacher use only)

Procedure

1) Put on your safety goggles, apron, and protective gloves.

2) Put 3 test tubes in a test-tube rack. From the dropper bottles, place 2 drops of butan-1-ol in the first test tube, 2 drops of butan-2-ol in the second test tube, and 2 drops of 2-methylpropan-2-ol in the test tube.

3) Under the fume hood, your teacher will add 10 drops of concentrated hydrochloric acid to each of your 3 test tubes. Gently shake the mixtures very carefully. Return to your lab bench with the test-tube rack and test tubes. Allow the tubes to stand for 1 min and observe for evidence of cloudiness.

4) Follow your teacher’s instructions for the disposal of the contents of the test tubes and for cleaning the test tubes.

5) Set up the 3 test tubes again, as described in the setup part of Step 2. This time, use 4 drops of each alcohol.

6) To each test tube, carefully add about 20 drops of potassium permanganate solution. Shake the mixture carefully.

7) Allow the test tubes to stand for 5 minutes with occasional gentle shaking observe and record the color of the solution in each tube.

Table 1: 2 Drops Of Each Alcohol, Hydrochloric Acid Added

Test Tube
Hydrochloric Acid Added
A
Butan-1-ol
Not cloudy
B
Butan-2-ol
Slightly Cloudy
C
2-methylpropan-2-ol
Very Cloudy

Table 2: 4 Drops Of Each Alcohol, Potassium Permanganate Added

Test Tube
Potassium Permanganate Added
A
Butan-1-ol
-Purple brown color
- Precipitate formed
B
Butan-2-ol

C
2-methylpropan-2-ol

Safety:

1. Alcohols are volatile and flammable.