Question

$C{H}_{3}COOH\stackrel{A}{\to }C{H}_{3}COCl\stackrel{B}{\to }C{H}_{3}CHO$

Identify the reagents $A$ and $B$ in the above reactions:

• A. $SO{Cl}_2,H_2/Pd-BaS{O}_4$
• B. $H_2/Pd-BaS{O}_4,SO{Cl}_2$
• C. $SO{Cl}_2,H_2{O}_2$
• D. $SO{Cl}_2,Os{O}_4$

Answer 1

Answer: (A)

$SO{Cl}_2,H_2/Pd-BaS{O}_4$

$C{H}_{3}COOH\stackrel{A}{\to }C{H}_{3}COCl$

This is the formation of acyl from the carboxylic acid by chlorination of the OH group of $C{H}_{3}COOH$ by the reagent $A$, which is $SOC{l}_2$,

$C{H}_{3}COCl\stackrel{B}{\to }C{H}_{3}CHO$,

This is the Rosenmund reaction for the formation of aldehyde by the reduction by the reagent $H_2/Pd-BaS{O}_4$. (B)