Equipment & Chemical Preparation
Sodium Borohydride Reduction of 2-Methylcyclohexanone
In this experiment, students will work in pairs to:
1. synthesize 2-methylcyclohexanol from 2-methylcyclohexanone using NaBH4
2. weigh the product & determine a % yield
3. analyze the product by IR spectroscopy
4. analyze the product using a gas chromatogram provided to them
Each student will synthesize 2-methylcyclohexanol starting with 1.2g of 2methylcyclohexanone, 200mg of NaBH4 and 10 ml of methanol. There are ~150 students. The
reaction is carried out in 50 ml Erlenmeyer flasks, immersed in an ice bath with stirring. The
work-up of the reaction involves addition of 5 ml of 3M NaOH and 5 ml of deionized water,
followed by extraction in a separatory funnel with CH2Cl2 (~35 ml each). The CH2Cl2 layer that
is separated in the extraction step is dried with ~100mg of MgSO4. The product is analyzed by
IR spectroscopy and gas chromatography (provided). The total materials need for the
experiment are listed in the table below.
Chemicals
2-Methylcyclohexanone
Sodium borohydride (NaBH4)
Methanol
3M NaOH
Deionized water
Magnesium sulfate
CH2Cl2
Equipment
50 ml Erlenmeyer flasks
Crystallizing dishes (for ice/water baths)
(Note Size: 125mm X 65 mm)
Magnetic stir bars
Salt Plates (for IR spectroscopy)
Disposable Pasteur pipettes
~300g
~50g
~4 liters
~3 liters
~3 liters
~50g
~4 liters
24
12
24
6 sets
2-3 boxes
Six bins should be prepared for each of the six lab benches containing the following items listed
in the table below. Quantities should be replenished throughout the week.
Experiment Bin (1 per bench)
2-methylcyclohexanone
NaBH4
Methanol
Deionized Water
3M NaOH
Dichloromethane
MgSO4
Magnetic Stir bars
50ml Erlenmeyer flasks
Crystallizing dishes
Salt plates
~30g (30ml)
~5g
~300ml
~200ml
~200ml
~1 liter
~4g
4
4
2
1 set