Alcohols and aldehydes may be oxidized into carboxylic acids. Alkenes may be converted into carboxylic acid through oxidative cleavage of the double bond with neutral or acid permanganate, for instance. However, the alkene must contain at least one hydrogen located at the double bond, otherwise only ketones are formed.

Conversion of Carboxylic Acid to Alkene

Introduction
Converting a carboxylic acid to an alkene involves the removal of a water molecule from the carboxylic acid molecule. This can be achieved through a variety of methods, such as using dehydration reagents or performing decarboxylation reactions. In this guide, we will discuss two common methods for converting carboxylic acids to alkenes.

Method 1: Dehydration of Carboxylic Acids
This method involves the use of dehydration reagents, such as strong acids, to remove a water molecule from the carboxylic acid molecule. The reaction mechanism typically involves protonation of the carboxylic acid followed by loss of a water molecule, resulting in the formation of an alkene.

Here are the steps involved in the dehydration of carboxylic acids to alkenes:

1. Protonation: The carboxylic acid is protonated by adding a strong acid, such as sulfuric acid (H2SO4) or phosphoric acid (H3PO4). This protonation increases the electrophilicity of the carbonyl carbon.

2. Water Elimination: The protonated carboxylic acid undergoes water elimination, resulting in the formation of a carbocation intermediate. This step involves the loss of a water molecule from the protonated carboxylic acid.

3. Deprotonation: The carbocation intermediate is deprotonated by a base, such as water or an alcohol, to form the alkene product.

Method 2: Decarboxylation
Decarboxylation involves the removal of a carboxyl group from a carboxylic acid molecule, resulting in the formation of an alkene. This method is typically used for carboxylic acids that have a β-carbon capable of forming a stable carbocation intermediate.

Here are the steps involved in the decarboxylation of carboxylic acids to alkenes:

1. Activation: The carboxylic acid is activated by converting it into a more reactive carboxylate anion. This can be achieved by treating the carboxylic acid with a base, such as sodium hydroxide (NaOH), to form the corresponding carboxylate salt.

2. Decarboxylation: The activated carboxylic acid undergoes decarboxylation, resulting in the loss of a carbon dioxide molecule. This step involves the formation of a carbocation intermediate on the β-carbon.

3. Deprotonation: The carbocation intermediate is deprotonated by a base, such as water or an alcohol, to form the alkene product.

Conclusion
Converting carboxylic acids to alkenes can be achieved through dehydration or decarboxylation reactions. Both methods involve the removal of a water molecule or a carboxyl group, respectively, to form an alkene. It is important to consider the reactivity of the carboxylic acid and the stability of the resulting carbocation intermediate when choosing a suitable method for the conversion.

Carboxylic acid treat with Pt/Ni/Pd