Q33 / 180 · COMEDK 2024 (Evening Shift) · Chemistry
Identify the end-product [D] formed when solution salicylate undergoes the following series of reactions
- A
- Correct answerB
- C
- D
Solution
The starting material (A) is sodium salicylate. Treatment with NaOH/CaO/Heat is a decarboxylation reaction (soda-lime decarboxylation), which removes the -COONa group and replaces it with a hydrogen atom. Subsequent treatment with HCl(aq) protonates the phenoxide ion to form phenol. Thus, (B) is phenol.
The reaction of phenol with NaOH(aq) converts it back to sodium phenoxide, which is also labeled as (B) in the reaction scheme. This is a nucleophilic species.
The final step involves the reaction of sodium phenoxide with allyl bromide ($CH_2=CH-CH_2Br$). This is a Williamson ether synthesis where the phenoxide oxygen acts as a nucleophile and attacks the electrophilic carbon of the allyl bromide, displacing the bromide ion. This results in the formation of allyl phenyl ether, which is $C_6H_5-O-CH_2-CH=CH_2$.
Answer:
The reaction of phenol with NaOH(aq) converts it back to sodium phenoxide, which is also labeled as (B) in the reaction scheme. This is a nucleophilic species.
The final step involves the reaction of sodium phenoxide with allyl bromide ($CH_2=CH-CH_2Br$). This is a Williamson ether synthesis where the phenoxide oxygen acts as a nucleophile and attacks the electrophilic carbon of the allyl bromide, displacing the bromide ion. This results in the formation of allyl phenyl ether, which is $C_6H_5-O-CH_2-CH=CH_2$.
Answer:
Hence, the correct answer is option: 'B'.