BRAINCAKENucleophilic Addition-Elimination Mechanism
Acyl chlorides and acid anhydrides react with nucleophiles by nucleophilic addition-elimination. AQA requires this mechanism for the reactions of acyl chlorides with water, alcohols, ammonia and primary amines. The example below is ethanoyl chloride with methanol.
Step 1: addition. A lone pair on the oxygen of methanol attacks the δ+ carbonyl carbon. At the same time the electrons of the C=O π bond move onto the oxygen atom. This forms an intermediate in which the carbon has four groups attached, the old carbonyl oxygen carries a negative charge, and the methanol oxygen carries a positive charge.
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Key terms in this lesson
- nucleophile
- An electron pair donor that is attracted to a region of positive charge and forms a new covalent bond by donating both electrons.
More in Carboxylic Acids and Derivatives
- Hydrolysis of Esters
- Vegetable Oils and Fats
- Soap Making
- Biodiesel
- Acyl Chlorides
- Acid Anhydrides
- Acylation of Water, Alcohols, Ammonia and Amines
- Manufacture of Aspirin
All 16 lessons in Carboxylic Acids and Derivatives · All AQA A-level Chemistry topics