Which of the following reaction cannot be used for the preparation of alkane?

Options

A. Corey-House synthesis
B. Frankland reaction
C. Clemmenson's reduction
D. Aromatization

Answer

To determine which of the following reactions cannot be used for the preparation of alkanes, let's analyze each option provided:

1. **CoriHouse Synthesis**:
- This reaction starts with alkyl halides and involves lithium to form lithium alkyl (RLi). When two moles of RLi react with cuprous chloride (CuCl), they form a dialkyl cuprate (R2Cu). This dialkyl cuprate can then react with another alkyl halide (RX) to produce an alkane (R-R). Thus, CoriHouse Synthesis can be used to prepare alkanes.

2. **Franklin Reaction**:
- In this reaction, zinc (Zn) is used to insert itself into the carbon-halogen bond of a dihalide (like CH2X-CH2X). This insertion leads to the formation of alkenes, but under certain conditions, it can also lead to the formation of alkanes through cyclization. Therefore, the Franklin reaction can also be used for the preparation of alkanes.

3. **Clemenson Reduction**:
- The Clemenson reduction involves the reduction of carbonyl compounds (like ketones or aldehydes) using zinc amalgam (Zn-Hg) and hydrochloric acid (HCl). This reaction converts the carbonyl group (C=O) into a methylene group (–CH2–), effectively producing an alkane. Thus, the Clemenson reduction can also be used to prepare alkanes.

4. **Aromatization**:
- Aromatization is a process that converts aliphatic hydrocarbons into aromatic hydrocarbons. For example, when normal hexane is subjected to an aromatization reaction using a catalytic mixture, it produces benzene, which is an aromatic compound. Therefore, aromatization does not produce alkanes.

Based on this analysis, the reaction that **cannot be used for the preparation of alkanes** is **Aromatization**.

### Final Answer:
**Aromatization** is the reaction that cannot be used for the preparation of alkanes.