Which of the following is not favourable for the propr dehydration of alcohol to form ether ?

Options

A. Good temperature control during reaction
B. Excess of alcohol
C. Presence of protic acids
D. Presence of bulky alkyl groups in the alcohol

Answer

To determine which condition is not favorable for the proper dehydration of alcohol to form ether, we need to analyze the factors that influence this reaction.

### Step-by-Step Solution:

1. **Understand the Reaction**: The dehydration of alcohol to form ether is known as the Williamson ether synthesis. It typically requires specific conditions to favor ether formation rather than the formation of alkenes.

2. **Identify the Alcohol Type**: The type of alcohol (primary, secondary, or tertiary) plays a crucial role in the reaction outcome.
- **Primary Alcohols**: Favorable for ether formation.
- **Secondary and Tertiary Alcohols**: More likely to undergo elimination reactions leading to alkene formation.

3. **Temperature Conditions**: The temperature at which the reaction is conducted is also critical.
- **Low Temperature (around 413 K)**: Favors ether formation from primary alcohols.
- **Higher Temperature (around 443 K)**: Favors the formation of alkenes from secondary and tertiary alcohols.

4. **Acidic Conditions**: The presence of an acid catalyst is necessary for the dehydration reaction. However, the type of alcohol and the temperature will determine the product.

5. **Conclusion**: Given the conditions mentioned, the presence of secondary or tertiary alcohols (or higher temperatures) is not favorable for the formation of ethers. Therefore, the presence of alkyl groups in alcohol (i.e., secondary or tertiary alcohols) is not favorable for ether formation.

### Final Answer:
The presence of secondary or tertiary alkyl groups in alcohol is not favorable for the proper dehydration of alcohol to form ether.

---