Different possible thermal decomposition pathways for peroxyesters are shown below. Match each pathway from List I with an appropriate structure from List II and select the correct answer using the code given below the lists.
List-I
P. Pathway P
Q. Pathway Q
R. Pathway R
S. Pathway S
List-II
(see structure)
(see structure)
(see structure)
(see structure)
Codes:
P
Q
R
S
(A)
1
3
4
2
(B)
2
4
3
1
(C)
4
1
2
3
(D)
3
2
1
4
1234
(A)P-1, Q-3, R-4, S-2✓ Correct
(B)P-2, Q-4, R-3, S-1
(C)P-4, Q-1, R-2, S-3
(D)P-3, Q-2, R-1, S-4
Answer: (A)
Solution
Peroxyesters undergo thermal decomposition through different pathways depending on their structure:
Pathway P involves homolytic cleavage of the O-O bond followed by decarboxylation, matching structure 1 (benzyl peroxyester).
Pathway Q involves a concerted mechanism with rearrangement, matching structure 3 (tertiary alkyl peroxyester with β-hydrogen).
Pathway R involves radical formation and subsequent reactions, matching structure 4 (tertiary alkyl benzoyl peroxide).
Pathway S involves simple O-O bond cleavage, matching structure 2 (methyl benzoyl peroxide).
Therefore, the correct matching is P-1, Q-3, R-4, S-2, which corresponds to option (A).
JEE Advanced · 2014 · 25 May 2014 · Paper 2 · Single correct option
