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Question #44398
The Question
Phenol is treated with and excess aqueous at . After complete consumption of , the resulting reaction mixture containing the sodium salt of the major product is divided into two equal aliquots, and . Aliquot is directly treated with aniline () at . Aliquot is first adjusted to a pH of using dilute , and then treated with aniline at . Both mixtures are subsequently subjected to a standard mild aqueous workup. Identify the major organic products isolated from aliquots and , respectively.
Options
- A.
: 2-Hydroxybenzaldehyde ; : 2-((Phenylimino)methyl)phenol
- B.
: 2-((Phenylimino)methyl)phenol ; : 2-Hydroxybenzaldehyde
- C.
: 2-((Phenylimino)methyl)phenol ; : 2-((Phenylimino)methyl)phenol
- D.
: 2-Hydroxybenzaldehyde ; : 2-(Phenylamino)methylphenol
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Mechanism_Trap
Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.
Concepts Behind This Question
Reimer-Tiemann Reaction|Schiff Base pH Dependence|Nucleophilic Acyl Substitution
Why This Question Is Tricky
Common Mistakes
The question tests the mechanistic constraints of Schiff base formation and the electronic effects of intermediates in the Reimer-Tiemann reaction.
Students often blindly chain reactions (Aldehyde + Amine -> Imine) without considering the pH dependence.
The 'hidden variable' is the strongly basic medium left over from the Reimer-Tiemann reaction.
This high pH completely inhibits imine formation by preventing the acid-catalyzed dehydration of the hemiaminal intermediate and by deactivating the carbonyl group via phenoxide resonance.
Neutralization to pH ~4.5 is strictly required for the reaction to proceed.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Alcohols, Phenols, and Ethers - Class 12 |
| Concept | Reimer-Tiemann Reaction |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |