Which of the following statements is/are correct about transacylation ?

Options

A. Amides can be prepared by `RCOCl` and anhydrides.
B. Anhydrides can be prepared by esters.
C. Esters can be prepared by anhydrides.
D. `RCOCl` can be prepared by anhydrides an esters.

Answer

To determine which statements about transacylation are correct, let's analyze each statement step by step.

### Step 1: Analyze Statement A
**Statement A:** Amides can be prepared by acid chlorides and anhydrides.

- **Explanation:**
- Acid chlorides (RCOCl) react with ammonia (NH3) to form amides (RCONH2) and release hydrochloric acid (HCl).
- Similarly, anhydrides (RCO-O-COR') react with ammonia to also produce amides. The reaction involves the breaking of the anhydride bond, resulting in the formation of an acid and an amide.

- **Conclusion:** This statement is correct.

### Step 2: Analyze Statement B
**Statement B:** Anhydrides can be prepared by esters.

- **Explanation:**
- This statement is incorrect. Anhydrides cannot be directly prepared from esters. Instead, anhydrides can be formed from the dehydration of carboxylic acids or by the reaction of acid chlorides with carboxylate salts.

- **Conclusion:** This statement is incorrect.

### Step 3: Analyze Statement C
**Statement C:** Esters can be prepared from anhydrides.

- **Explanation:**
- This statement is correct. Anhydrides can react with alcohols to form esters. For example, if an anhydride reacts with methanol (CH3OH), it will yield an ester and a carboxylic acid.

- **Conclusion:** This statement is correct.

### Step 4: Analyze Statement D
**Statement D:** Acid chlorides can be prepared from anhydrides and esters.

- **Explanation:**
- This statement is incorrect. Acid chlorides cannot be formed directly from anhydrides or esters. Acid chlorides are typically prepared from carboxylic acids through the reaction with thionyl chloride (SOCl2) or oxalyl chloride (COCl)2.

- **Conclusion:** This statement is incorrect.

### Final Conclusion
Based on the analysis:
- **Correct Statements:** A and C
- **Incorrect Statements:** B and D

### Summary of Correct Answers
The correct statements about transacylation are:
- **A:** Amides can be prepared by acid chlorides and anhydrides.
- **C:** Esters can be prepared from anhydrides.

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