Question

How can the following conversions be brought about:

(i) Acetic acid to methyl cyanide.
(ii) Acetaldehyde to formaldehyde. 
(iii) Nitrobenzene to 2, 4, 6 tribromoaniline.

Answer 1

(i)

(ii)

$$\underset{\text{Acetaldehyde}}{\mathrm{CH}{\phantom{A}}_3\mathrm{CHO}}\stackrel{(\mathrm{O})}{\to }\underset{\text{Acetic acid}}{\mathrm{CH}{\phantom{A}}_3\mathrm{COOH}}\underset{\mathrm{\Delta }(-\mathrm{H}{\phantom{A}}_2\mathrm{O})}{\overset{+\mathrm{NH}{\phantom{A}}_3}{\to }}+\underset{\text{Acetanide}}{\mathrm{CH}{\phantom{A}}_3\mathrm{CONH}{\phantom{A}}_2}\stackrel{\mathrm{Br}{\phantom{A}}_2/\mathrm{KOH}}{\to }\underset{\text{Formaldehyde}}{\mathrm{HCHO}}\stackrel{(\mathrm{O})}{\leftarrow }\underset{\text{Methyl alcohol}}{\mathrm{CH}{\phantom{A}}_3\mathrm{OH}}\stackrel{\mathrm{NaNO}{\phantom{A}}_2+\mathrm{HCl}}{\leftarrow }\underset{\text{Methylamine}}{\mathrm{CH}{\phantom{A}}_3\mathrm{NH}{\phantom{A}}_2}$$

(iii)