How butanoic acid is prepared from the following starting chemicals;A. An AlcoholB. An Alkyl HalideC. An alkene

The preparation of butanoic acid (C₃H₇COOH) from various starting materials can be accomplished through different chemical reactions. Let's explore how it can be synthesized from an alcohol, an alkyl halide, and an alkene.

### A. Preparation of Butanoic Acid from an Alcohol
If we start with an alcohol, we can use **1-butanol (C₄H₉OH)** as the precursor. The process involves the oxidation of the alcohol to a carboxylic acid.

1. **Oxidation Reaction**:
- Butanoic acid can be prepared by oxidizing 1-butanol using a strong oxidizing agent like **potassium permanganate (KMnO₄)** or **chromic acid (H₂CrO₄)**.
- The reaction is as follows:
\[
\text{C₄H₉OH} \overset{[O]}{\rightarrow} \text{C₃H₇COOH}
\]
Here, [O] represents the oxidizing agent.
- The alcohol is first oxidized to butanal (an aldehyde), and then the aldehyde is further oxidized to butanoic acid.

### B. Preparation of Butanoic Acid from an Alkyl Halide
If we start with an alkyl halide like **1-bromobutane (C₄H₉Br)**, we can use hydrolysis and oxidation to convert it into butanoic acid.

1. **Nucleophilic Substitution Reaction (Hydrolysis)**:
- 1-bromobutane can be hydrolyzed to 1-butanol using an aqueous solution of a hydroxide like **NaOH**.
- The reaction is:
\[
\text{C₄H₉Br} + \text{NaOH} \rightarrow \text{C₄H₉OH} + \text{NaBr}
\]

2. **Oxidation**:
- As in the previous case, 1-butanol is then oxidized to butanoic acid using a strong oxidizing agent like KMnO₄ or chromic acid.
- The overall reaction from 1-bromobutane to butanoic acid:
\[
\text{C₄H₉Br} \rightarrow \text{C₄H₉OH} \overset{[O]}{\rightarrow} \text{C₃H₇COOH}
\]

### C. Preparation of Butanoic Acid from an Alkene
If we start with an alkene like **1-butene (C₄H₈)**, we can use oxidation reactions to break the double bond and add oxygen to form butanoic acid.

1. **Oxidative Cleavage of Alkene**:
- The double bond in 1-butene can be cleaved using **potassium permanganate (KMnO₄)** or **ozone (O₃)** followed by oxidative workup.
- In the case of oxidative cleavage with KMnO₄:
\[
\text{C₄H₈} \overset{KMnO₄}{\rightarrow} \text{C₃H₇COOH} + CO₂
\]
The butene molecule is oxidatively cleaved, and one of the fragments is oxidized to butanoic acid.
- This reaction specifically cleaves the double bond and oxidizes the carbon atoms, forming carboxylic acids at the ends of the cleaved fragments.

### Summary of Reactions:
1. **From Alcohol (1-butanol)**: Oxidation → Butanoic acid.
2. **From Alkyl Halide (1-bromobutane)**: Hydrolysis → 1-butanol, then oxidation → Butanoic acid.
3. **From Alkene (1-butene)**: Oxidative cleavage → Butanoic acid.

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