Fundamentals of Organic ChemistryChemistryCarboxylic Acid Derivatives
Which of the following statements is true regarding the amount of AlCl ₃ required during Friedel-Crafts acetylation using acetyl chloride compared to acetic anhydride?
Options
- AAcetylation with acetyl chloride requires a greater amount.
- BThe relative amount required cannot be definitely stated.
- CBoth require the same amount.
- DAcetylation with acetic anhydride requires a greater amount.
Correct answer
D. Acetylation with acetic anhydride requires a greater amount.
Step-by-step solution
In Friedel-Crafts acetylation using acetyl chloride, slightly more than one equivalent of anhydrous AlCl ₃ is required because the product ketone forms a complex with AlCl ₃ . When acetic anhydride is used as the acetylating agent, the reaction produces acetic acid as a byproduct. Both the product ketone and the byproduct acetic acid form stable complexes with AlCl ₃ . Therefore, slightly more than two equivalents of AlCl ₃ are required when acetic anhydride is used. Thus, acetylation with acetic anhydride requires