Jones oxidation

Jones Oxidation

Schematic representation of the Jones oxidation.

The Jones oxidation is a chemical reaction used to oxidize primary alcohols to carboxylic acids and secondary alcohols to ketones. This reaction is named after Sir Ewart Jones, who developed the method. The Jones oxidation is a powerful and widely used method in organic chemistry for the transformation of alcohols into more oxidized functional groups.

Mechanism

The Jones oxidation involves the use of chromium trioxide (CrO_) in the presence of sulfuric acid (H_SO_) and acetone as a solvent. The reaction proceeds through the formation of a chromate ester intermediate, which undergoes a series of redox reactions to yield the oxidized product.

Step 1: Formation of Chromate Ester

In the first step, the alcohol reacts with chromium trioxide in the presence of sulfuric acid to form a chromate ester. This step is crucial as it activates the alcohol for further oxidation.

Step 2: Redox Reaction

The chromate ester undergoes a redox reaction, where the chromium is reduced from the +6 oxidation state to the +3 oxidation state, and the alcohol is oxidized to the corresponding carbonyl compound. For primary alcohols, this results in the formation of carboxylic acids, while secondary alcohols are converted to ketones.

Applications

The Jones oxidation is particularly useful in synthetic organic chemistry for the preparation of carboxylic acids and ketones from alcohols. It is often employed in the synthesis of complex molecules where selective oxidation is required.

Limitations

One of the main limitations of the Jones oxidation is its use of toxic chromium compounds, which pose environmental and safety concerns. Additionally, the reaction is not suitable for substrates that are sensitive to acidic conditions or that contain other functional groups that may be oxidized under the reaction conditions.

Related Pages

• Oxidation (chemistry)
• Alcohol oxidation
• Chromium trioxide
• Ewart Jones