a) Write the mechanism of the following reaction: $$2\,\mathrm{CH_3CH_2OH}\xrightarrow{H^+}\mathrm{CH_3CH_2{-}O{-}CH_2CH_3}$$ b) Write the equation involved in the acetylation of salicylic acid.

(a) Protonation → S_N2 attack by the second ethanol → deprotonation (three steps, water displaced). (b) Salicylic acid + (CH₃CO)₂O →H⁺→ aspirin + CH₃COOH.

CBSE Class 12 · 2015 · Delhi · Alcohols Phenols and EthersShort Answer

WhatsApp Email

a) Write the mechanism of the following reaction:

2 C H_{3} C H_{2} OH H^{+} C H_{3} C H_{2} - O - C H_{2} C H_{3}

b) Write the equation involved in the acetylation of salicylic acid.

Solution

(a) Step 1: CH

_{3}

_{2}

OH + H

^{+}

→ CH

_{3}

_{2}

\overset{+}{O}H

_{2}

.
Step 2 (S

_{N}

2): CH

_{3}

_{2}

OH attacks the protonated molecule's α-carbon, expelling H

_{2}

O → CH

_{3}

_{2}

\overset{+}{O}(H)CH

_{2}

_{3}

.
Step 3: loss of H

^{+}

→ CH

_{3}

_{2}

OCH

_{2}

_{3}

.
(b) Acetylation of the phenolic –OH:

o - HO C_{6} H_{4} COOH + (C H_{3} CO)_{2} O H^{+} o - C H_{3} COO - C_{6} H_{4} - COOH (aspirin) + C H_{3} COOH

CBSE Class 12 Board · 2015 · Delhi · Subjective

Practise more: all CBSE board PYQs on Alcohols Phenols and Ethers →

CBSE Class 12 · 2015 · Delhi · Alcohols Phenols and EthersShort Answer

Solution

More board questions on Alcohols Phenols and Ethers