Organic Chemistry Laboratory I - Chem 341

Quiz 6a

1. Label the following reaction as an oxidation, a reduction, or neither. (2 Pts)

2. Consider the oxidation of cyclododecanol and answer the following question: What was the purpose of the sodium bicarbonate wash during the workup? (1 pt)

Sodium bicarbonate is a weak base and so it neutralizes any excess acetic acid.

3. What was the purpose of the starch iodide test last week? (1 pt)

Starch/Iodine test was performed to determine whether there is an excess of oxidizing agent present in the reaction mixture. If we did not have excess reagent, then it is possible that some of the starting alcohol was not converted to the ketone. This would reduce the yield and complicate the purification.

A positive test turns the paper black and indicates excess bleach.

4. What region of the infrared spectrum (4000 – 600 cm^-1) would an aliphatic C-H bond vibration show up in? (2 pts)

2950 (2 points for +/- 30cm^{-1 )}

5. Why is it inappropriate to wash an IR salt plate with water? (2 pts)

Salt plates are made of sodium chloride or potassium bromide. Both are very soluble in water, so water will dissolve the salt plate. For this reason you need to use an organic solvent that adsorbs very little residual water from the atmosphere. Dichloromethane (methylene chloride or CH₂Cl₂) is the best solvent for cleaning salt plates.

6. Draw the structure of the major organic product. (2 pts)