18 Questions
What is the physical state of Para Red dye?
Solid
When was Para Red dye discovered?
1880
What is the classification basis of Azo dyes?
Number of Nitrogen atoms in the structure
Why is Diazonium salt kept at an ice bath during synthesis?
To prevent decomposition
What is the limiting reagent in the synthesis of Nitroanilide?
Acetanilide
What color does Para Red dye impart to cellulose fabrics?
Red
What is the function of Azo group containing cyclized-cyanine derivatives ACC1 and ACC2?
Two-photon photodynamic therapy for cancer
Which industry widely uses Azo dyes for dyeing purposes?
Textile industry
What is the color of Benzoic Acid?
Colorless
Where is Benzoic Acid commonly found?
Castoreum from anal sacs of beavers
What is the main reason for lessening the use of Azo Dyes?
They have a toxic effect
What is the application of Azo Dyes in the pharmaceutical industry?
Coloring pharmaceutical agents
How is benzoic acid produced commercially?
By oxidation of toluene with oxygen
Which compound can increase in humans when exposed to Toluene or Benzoic Acid?
Hippuric acid
Which reaction results in equal amounts of benzoate and benzyl alcohol?
Autoxidation of benzaldehyde
What is the limiting reagent in the Cannizzaro reaction for the preparation of benzoic acid?
Benzaldehyde
In which conditions can benzonitrile be hydrolyzed to form benzoic acid?
In acidic conditions
What is a common application of benzoic acid in pharmaceuticals?
Antifungal agent in ointments
Study Notes
Azo Dyes
- Azo dyes are widely used in the pharmaceutical industry for coloring pharmaceutical agents.
- They are used in hypnotic medicine for the treatment of insomnia.
- Azo group containing cyclized-cyanine derivatives (ACC1 and ACC2) are used in two-photon photodynamic therapy for cancer treatment.
- They are used as complexometric indicators, undergoing a color change in the presence of metal ions like calcium and magnesium.
- Azo dyes are widely used in the textile industry for dyeing purposes.
- They are used in cosmetics, papers, plastics, and food, etc.
Benzoic Acid
- Chemical Formula: C6H5COOH
- Functional group: Carboxylic acid
- It is a colorless crystalline solid and a simple aromatic carboxylic acid.
- The name is derived from gum benzoin, which was for long time its only known source.
- Benzoic acid is used to calibrate a bomb calorimeter.
- It has antifungal abilities.
- It is one of the chemical compounds found in castoreum.
Para Red Dye
- Structure: The encircled part is the Azo group.
- Belongs to monoazo dye.
- Melting Point: 248-252°C
- Molecular Weight: 293.28g
- Physical state: Dark Red Powder
- Solubility in Water: Insoluble
- It was discovered in 1880 by Von Gallois and Ullrich.
- Para Red (Paranitraniline red, Pigment red) is a dye that dyes cellulose fabrics a brilliant red color but is not very fast.
- It is considered potentially genotoxic and possibly carcinogenic; skin, respiratory tract, and severe eye irritant.
Classification of Azo Dyes
- Azo dyes are classified depending on how many azo groups are in the structure.
Industrial Preparation of Benzoic Acid
- Benzoic acid is produced commercially by partial oxidation process of toluene with oxygen.
- The process is catalyzed by cobalt or manganese naphthenates.
- The process uses cheap raw materials and proceeds in high yield.
Preparation of Benzoic Acid
- Benzoic acid can be prepared by hydrolysis of benzonitrile and benzamide.
- It can also be prepared by oxidation of benzyl chloride in the presence of alkaline KmnO4.
- The Cannizzaro reaction of benzaldehyde also produces benzoic acid and benzyl alcohol.
Test your knowledge on the actual and theoretical yield calculations for Nitroacetanilide, 4-Nitroaniline, P-Red Dye, and the application of Azo dyes in various industries including pharmaceuticals and thermal transfer printers.
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