1. Three drops of concentrated sulfuric acid are added to the reaction mixture a
ID: 503266 • Letter: 1
Question
1. Three drops of concentrated sulfuric acid are added to the reaction mixture at the beginning of this reaction. What is the role of this compound in the reaction? 2. Addition of a large amount (several ml) of concentrated sulfuric acid to the reaction mixture at the beginning of this reaction results in the formation of none of the desired acetylsalicylic acid product. Give a rationale for this observation. 3 Acetylation can be conducted using a base in place of the acid Which base, pyridine or aniline, would be a better choice for the a of phenol using acetic anhydride? Explain your choice clearly.Explanation / Answer
1. It is used to break the complex formed by the oxygen atom with AlCl3.Salicylic acid reacts with acetic anhydride under acidic conditions to form aspirin and acetic acid (acid catalyzed reaction). sulphuric acid ia a catalyst.
2.We want to protonate the carbonyl group on the anhydride without protonating the phenolic hydroxy group of salicylic acid bacause a protonated hydroxy group is a terrible nucleophile adding a large excess of aqueous acid would also hydrolyze the anhydride.
3.The pyridine forms the hydrogen bonds with the phenolic hydrogen which activates the phenol to acetylation
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