Question

What will be the oxidation product of toluene and styrene in presence of alkaline \(\mathrm{KMnO}_{4}\) as an oxidizing agent?

Short answer

Both toluene and styrene oxidize to form benzoic acid using alkaline KMnO₄.

Step-by-step solution

Determine Oxidation Conditions

Understand that alkaline KMnO₄ is a strong oxidizing agent, capable of breaking carbon-carbon double bonds and oxidizing alkyl groups.

Oxidation of Toluene Overview

Toluene (C6H5CH3) contains a methyl group attached to a benzene ring. When oxidized by KMnO₄, the methyl group is converted to a carboxylic acid.

Identify Toluene Oxidation Product

The methyl group in toluene is oxidized by alkaline KMnO₄ to form a carboxylic acid, resulting in benzoic acid (C6H5COOH) as the oxidation product.

Oxidation of Styrene Overview

Styrene (C6H5CH=CH2) contains a vinyl group attached to a benzene ring. KMnO₄ breaks the carbon-carbon double bond in the vinyl group.

Identify Styrene Oxidation Product

The double bond in styrene is broken, converting the entire vinyl group into a carboxylic acid. This results in the formation of benzoic acid (C6H5COOH) as the oxidation product.

Key concepts

Alkaline KMnO4 as Oxidizing Agent

Alkaline potassium permanganate (\(\text{KMnO}_4\)) is a powerful oxidizing agent used extensively in organic chemistry. It is particularly effective in transforming functional groups and breaking chemical bonds. This agent works by accepting electrons from other molecules.
As an oxidizing agent, \(\text{KMnO}_4\) can target various organic compounds. Under alkaline conditions, it can break carbon-carbon double bonds and convert alkyl groups into more oxidized forms such as carboxylic acids. The ability to transform both unsaturated and saturated compounds makes alkaline \(\text{KMnO}_4\) an important tool in synthetic chemistry.

Oxidation of Toluene

When toluene is treated with alkaline \(\text{KMnO}_4\), it undergoes oxidation due to its methyl group. Toluene consists of a benzene ring bonded to a methyl group, denoted as \(\text{C}_6\text{H}_5\text{CH}_3\). The methyl group is the primary site of oxidation in this reaction.
During the oxidation process, the strong oxidizing power of \(\text{KMnO}_4\) converts the methyl group (-CH₃) attached to the benzene ring into a carboxylic acid group (-COOH). As a result, toluene is transformed into benzoic acid (\(\text{C}_6\text{H}_5\text{COOH}\)). This reaction showcases the agent's ability to fully oxidize a methyl group to a terminal carboxylic acid.

Oxidation of Styrene

Styrene, also known as vinylbenzene or \(\text{C}_6\text{H}_5\text{CH}=\text{CH}_2\), presents a vinyl group attached to a benzene ring. While toluene is primarily oxidized at its methyl group, styrene undergoes oxidation at the carbon-carbon double bond. This double bond is susceptible to the oxidizing action of alkaline \(\text{KMnO}_4\).
When styrene is treated with alkaline \(\text{KMnO}_4\), the double bond is broken, leading to the formation of a diol intermediate. Eventually, this intermediate continues to oxidize, resulting in the conversion of the entire vinyl group into a carboxylic acid group, forming benzoic acid as the oxidation product. The oxidation of styrene highlights how \(\text{KMnO}_4\) effectively disrupts unsaturated bonds to yield carboxylic acids.

Oxidation Products

The oxidation of organic compounds using alkaline \(\text{KMnO}_4\) predominantly results in the formation of carboxylic acids, especially when targeting alkyl groups or unsaturated bonds.
After the reaction with alkaline \(\text{KMnO}_4\), both toluene and styrene yield benzoic acid. This product serves as a classic example of oxidation results where both an alkyl group and a double bond are converted into a corresponding carboxylic acid. \(\text{KMnO}_4\)'s oxidizing capabilities make it a staple in reactions to generate such acids from simple hydrocarbons.

Carboxylic Acid Formation

Carboxylic acids are a significant class of organic compounds, characterized by the presence of a carboxyl group (-COOH). The oxidation of hydrocarbons such as toluene and styrene using alkaline \(\text{KMnO}_4\) results in the formation of these acids.
The conversion of functional groups such as methyl groups or double bonds into carboxylic acids involves the addition of oxygen atoms and the stabilization of the resulting acid group. This transformation is crucial in organic synthesis, as carboxylic acids are precursors to numerous other chemical compounds.