Question

Which of the following will produce cyclic ketone on heating?
(A) $ C{H_2}{\left( {COOH} \right)_2} $
(B)

C)

D)

Answer 1

Hint: A cyclic ketone is a ketone in whose molecule the carbon atoms bonded to the carbonyl carbon are connected by one or more carbon chains. These are synthesized when aliphatic dicarboxylic acid undergoes heat treatment.

Complete answer:
When a dicarboxylic aliphatic acid is heated, then five or six-membered cyclic anhydride is formed because they are highly stable. However, compounds like adipic acid (six carbon atoms) & higher acids will give rings of seven or more members which are very unstable. So, on heating, they give cyclic ketones with a loss of $ C{O_2} $ .
As options A, B, and C have a lesser number of carbon atoms than option D, option D has seven carbons so it can form a cyclic ketone.

Hence, the correct option is (D).

Note:
The simplest category of cyclic ketone has the formula $ {\left( {C{H_2}} \right)_n}CO $ , where n varies from two in cyclo acetone to the tenth place. There are larger derivatives. Cyclohexanone is a symmetrical cyclic ketone and an important intermediate for the manufacture of nylon.