1. Oxidation of Cyclododecanol

2. Oxidation is defined as…
Loss of electrons
Increase in oxidation number
These work well for metallics
Addition of an oxygen atom
Removal of 2 hydrogen atoms

3. Calculating Oxidation Number
For carbon:
Assign oxidation numbers to the atoms attached to the carbon using the following values:
+1 for hydrogen
-1 for halogens, nitrogen, oxygen, and sulfur
0 for carbon
Sum the oxidation numbers of these atoms.
If an atom is double bonded, multiply its oxidation number by 2; If triple bonded, multiply by 3.
Determine that the sum of the number from step 2 and the oxidation number of the carbon atom equals the charge on the carbon atom, which is zero unless it bears a +/- charge.

4. Calculating Oxidation Number
For other atoms (esp. those in polyatomic ions)
Hydrogen must always have an oxidation number of +1.
Oxygen must always have an oxidation number of -2.
The sum of all the oxidation numbers must be zero, so then solve for the atom under consideration.

5. Oxidizing Reagents Common examples from the text – KMnO4
H2CrO4 or H2SO4 and CrO3
HNO3
Pyridinium chlorochromate
5. Hypochlorous acid – Sodium hypochlorite (we will be using this today) is the main ingredient in household bleach.

6. PROCEDURE:
Cyclododecanol is dissolved in acetone to which acetic acid is added.
The solution is warmed to 45oC and held there using a water bath. Bath temperature monitored 40-50oC
Sodium hypochlorite (4.5mL) is added slowly over about 20 minutes.

7. Note: Carbon goes from 0 to +2 (2 e- change)
Chlorine goes from +1 to -1 (2 e- change)

8. Add more bleach as needed to ensure an excess.
To ensure an excess of hypochlorite, test using starch/iodide paper (which consists of KI and starch).
Cl goes from +1 to -1 (2 e- change)
I goes from -1 to 0 (1 e- change)
Iodine reacts with polysaccharides such as starch to form a complex ion which is blue-black in color.
Add more bleach as needed to ensure an excess.
Transfer to a separatory funnel – wash the flask with ether and add that to the funnel – shake and separate layers. Keep both layers. (Ether extraction of aq. layer)
Extract the aq. layer with another 5 mL portion of ether and combine with the 1st 5 mL of ether. The product should be in the ether layer.

9. Wash the combined ether layers with:
- bicarbonate – to remove (acetic) acid
NaHCO3 + HC2H3O2 = NaC2H3O2 + H2O + CO2(g)
- bisulfite – to remove sodium hypochlorite
ClO NaHSO3 = Cl NaHSO4
- saturated aq. NaCl solution (salting out)
Dry over anhydrous Na2SO4 for at least 15 minutes.
Carefully pipette your product into another (pre- weighed, empty) vial to separate it from the desiccant.
Weigh the combined mass (and then subtract out the mass of the empty vial to get the mass of your product).

10. Confirmatory Tests
How do you know you have performed a chemical change?
Ketones will react with 2,4-dinitrophenylhydrazine to give a precipitate ranging in color from yellow to red; alcohols will not. Test both the starting compound and the product by mixing a drop of each reagent and observing any precipitate.

11. To Prepare Your NB…
7 Chemicals: cyclododecanol, acetone, glacial acetic acid, sodium hypochlorite, diethyl ether, cyclododecanone, 2,4-dinitrophenylhydrazine
5 Chemical Reactions:
Overall oxidation reaction
How HClO is generated in solution with acetic acid
Neutralization of acetic acid with sodium bicarbonate
Bisulfite wash to remove hypochlorite
Confirmatory test (but CUSTOMIZE to our specific reaction)
Use the procedure in this powerpoint as a guide and pgs. 594 to help you write a procedure in your NB.
Figure 2.34 (b) on pg. 51, except we’re using water not oil.

12. Calculations
Calculate the theoretical yield – remember hypochlorite is in excess.
2. Calculate the % yield based on the mass of product that you recovered.