Question

What are X and Z in the following reaction sequence? 

 

• A. CrO\(_3\)/H\(_2\)SO\(_4\); Propiophenone
• B. CrO\(_3\)/H\(_2\)SO\(_4\); Acetophenone
• C. PCC; Propiophenone
• D. PCC; Acetophenone

Hint:

Remember the oxidation reactions of alcohols and the Friedel-Crafts acylation reaction.

Answer 1

The Correct Option is A

1. Reaction of propan-1-ol with X:

Propan-1-ol (CH\(_3\)CH\(_2\)CH\(_2\)OH) is a primary alcohol.
Primary alcohols can be oxidized to aldehydes or carboxylic acids.
CrO\(_3\)/H\(_2\)SO\(_4\) (Jones reagent) is a strong oxidizing agent that will oxidize primary alcohols to carboxylic acids.
PCC (pyridinium chlorochromate) is a mild oxidizing agent that will oxidize primary alcohols to aldehydes.
Since the product Y reacts with benzene in the presence of anhydrous AlCl\(_3\), it must be an acid chloride.
Therefore, X must be CrO\(_3\)/H\(_2\)SO\(_4\), which will oxidize propan-1-ol to propanoic acid (CH\(_3\)CH\(_2\)COOH).

2. Reaction of propanoic acid with SOCl\(_2\):

Propanoic acid reacts with thionyl chloride (SOCl\(_2\)) to form propanoyl chloride (CH\(_3\)CH\(_2\)COCl).
Y is propanoyl chloride.

3. Reaction of propanoyl chloride with benzene in presence of anhydrous AlCl\(_3\):

This is a Friedel-Crafts acylation reaction.
Propanoyl chloride reacts with benzene to form propiophenone (C\(_6\)H\(_5\)COCH\(_2\)CH\(_3\)).
Z is propiophenone.

Therefore, X is CrO\(_3\)/H\(_2\)SO\(_4\) and Z is propiophenone.

Final Answer:
CrO\(_3\)/H\(_2\)SO\(_4\); Propiophenone.