Chemical Process - Engineering

Q1:

Catalytic oxidation of toluene produces

A styrene

B phenol

C benzene

D tri-nitro-toluene

ANS:B - phenol

Catalytic oxidation of toluene produces benzaldehyde. Catalytic oxidation of toluene produces benzaldehyde through a controlled reaction that involves the introduction of oxygen. Here’s how the process works:

Reaction Overview:

  1. Starting Material: Toluene (C₇H₈) is an aromatic hydrocarbon with a methyl group attached to a benzene ring.
  2. Catalytic Oxidation: In this process, toluene is oxidized using a catalyst (often a metal catalyst like palladium or platinum) in the presence of oxygen (or air). The reaction typically occurs under controlled temperatures and pressures.

Reaction Mechanism:

  • Oxidation Process: The oxidation of toluene involves the removal of hydrogen atoms and the addition of oxygen, transforming the methyl group (-CH₃) into a formyl group (-CHO), resulting in benzaldehyde (C₇H₆O). C7H8+O2→C7H6O+H2O\text{C}_7\text{H}_8 + \text{O}_2 \rightarrow \text{C}_7\text{H}_6\text{O} + \text{H}_2\text{O}C7​H8​+O2​→C7​H6​O+H2​O

Key Features:

  1. Selectivity: The catalytic oxidation is selective, meaning it preferentially produces benzaldehyde over other potential products, such as further oxidation to carboxylic acids.
  2. Conditions: The reaction conditions, including temperature and pressure, are optimized to maximize the yield of benzaldehyde and minimize side reactions.

Applications of Benzaldehyde:

Benzaldehyde is an important chemical used in various applications, including:
  • Flavoring and Fragrance: It is commonly used in the food industry and perfumery for its pleasant almond-like aroma.
  • Chemical Intermediate: Benzaldehyde serves as a precursor for the synthesis of other chemicals, including pharmaceuticals, dyes, and resins.

Summary:

The catalytic oxidation of toluene effectively converts it into benzaldehyde through a controlled oxidation process, highlighting its significance in organic synthesis and industrial applications.