Question

a) Write a short note on Reimer- Tiemann reaction.

b) Two isomeric compounds (A) and (B) have molecular formula $C_7{H}_{7}OH$ (A) gives violet colour with neutral ferric chloride solution whereas (B) does not. Suggest structures for (A) and (B)

Answer 1

a) Reimer-Tiemann reaction: When the phenol is treated with chlorophyll in presence of aqueous sodium or potassium hydroxide at 340 K followed by hydrolysis of the resulting product gives 2-hydroxybenzaldehyde as the major product. This reaction is called the Reimer-Tiemann reaction.

b) In the above image, structure (1) is A and structure (2) is B. We can see that the structure(1) has Oh group directly attached to the aromatic ring creating an " enol" system which shows violet colour with ferric chloride solution while the benzyl alcohol will not show any reaction with the solution.