Question

Which of the following will give a positive carbylamine test?

• A. N,N-Dimethylaniline
• B. 2,4,6-Trimethylaniline
• C. p-Toluidine
• D. p-Methylbenzylamine
• E. Ethylmethylamine

Answer 1

Answer: (B), (C), (D)

p-Methylbenzylamine

Aliphatic and aromatic primary amines on heating with CHCl₃
and ethanolic KOH form isocyanides or carbylamines.
$R-{\mathrm{NH}}_2+{\mathrm{CHCl}}_3+3\mathrm{KOH}\stackrel{\Delta }{\to }R-\mathrm{NC}+3\mathrm{KCl}+3H_{2}O$Secondary and tertiary amines do not show this reaction.
N,N-Dimethylaniline and ethylmethylamine are tertiary and secondary amines respectively, and hence they give negative result in carbylamine test.
2,4,6-Trimethylaniline, p-toluidine( or 4-methylaniline) and p-methylbenzylamine are primary amines.