Question

Successfully converting 3-phenylpropanol to 3-phenylpropanoic acid by the Jones oxidation requires the oxidizing agent, the solvent, and: (A) dilute sulfuric acid. (B) dilute sodium hydroxide. (C) anhydrous conditions. (D) high temperature.

Short answer

(A) dilute sulfuric acid.

Step-by-step solution

- Identify the conversion reaction

The task is to convert 3-phenylpropanol to 3-phenylpropanoic acid using Jones oxidation. Recognize that this is an oxidation reaction where an alcohol is converted to a carboxylic acid.

- Understand Jones oxidation

Jones oxidation utilizes a chromic acid solution (formed from chromium trioxide and sulfuric acid) in an aqueous acetone solvent. The purpose is to oxidize alcohols.

- Analyze the conditions of Jones oxidation

Jones oxidation requires water to form the chromic acid and acidic conditions to maintain the oxidation process. Hence, dilute sulfuric acid is necessary in the reaction.

- Confirm the correct answer

Given the oxidation agent (chromic acid from CrO3 and H2SO4), the solvent (aqueous acetone), and the final requirements (acidic environment), the correct answer is (A) dilute sulfuric acid.

Key concepts

oxidizing agents

Oxidizing agents are chemicals that facilitate oxidation reactions, key processes in organic chemistry. They work by accepting electrons from other substances during a reaction. The substance that donates the electrons gets oxidized. Oxidizing agents are crucial in converting different types of organic compounds.
Common examples include:

• Potassium permanganate (KMnO₄)
• Chromic acid (H₂CrO₄)
• Ozone (O₃)
• Hydrogen peroxide (H₂O₂)

In the context of Jones oxidation, the chromic acid is the oxidizing agent. By accepting electrons from the alcohol, it helps convert it to a carboxylic acid. This reaction is highly efficient for transforming primary alcohols (like 3-phenylpropanol) into carboxylic acids (like 3-phenylpropanoic acid). Always ensure the right conditions – typically acidic and aqueous – to facilitate the proper functioning of these agents.

alcohol to carboxylic acid conversion

The transformation of an alcohol to a carboxylic acid is a commonly encountered reaction in organic chemistry. This is often done through oxidation reactions, which add oxygen or remove hydrogen from the molecule.
Here's a step-by-step breakdown:

• The alcohol (R-CH₂OH) is first converted to an aldehyde (R-CHO).
• The aldehyde is further oxidized to a carboxylic acid (R-COOH).

For example, 3-phenylpropanol (C₆H₅-CH₂-CH₂-CH₂OH) is first converted to 3-phenylpropanal (C₆H₅-CH₂-CH₂-CHO) and then to 3-phenylpropanoic acid (C₆H₅-CH₂-CH₂-COOH). The Jones oxidation is a popular method for such conversions since it utilizes chromic acid (H₂CrO₄) in an acidic medium, ensuring a complete transformation.

chromic acid

Chromic acid (H₂CrO₄) is an effective oxidizing agent used in various oxidation reactions in organic synthesis. It's commonly prepared in situ by mixing chromium trioxide (CrO₃) with dilute sulfuric acid (H₂SO₄).
Key features of Chromic Acid in Organic Chemistry:

• Strong oxidizing power: Effective in converting primary alcohols into carboxylic acids and secondary alcohols into ketones.
• Acidic conditions: Requires aqueous and acidic conditions (like dilute sulfuric acid) for optimal performance.
• Stability: Often used in controlled environments due to its highly oxidative nature.

During a Jones oxidation reaction, chromic acid accepts electrons from the alcohol hydrogen atoms, facilitating the transformation to carboxylic acids. This makes it particularly useful for applications requiring strong, reliable oxidation.