Preparation of P Nitroacetanilide

Introduction

P-Nitroacetanilide contains Acetamido (-NHCOCH3) group in Acetanilide, is determined as the para and ortho directing for electrophiles. The compounds are mainly formed by nitration reaction of Acetanilide. The reaction results in mixture of p-Nitroacetanilide and o-Nitroacetanilide in crystalline shape.

What is P-Nitroacetanilide?

P-Nitroacetanilide is determined as the 4-Nitroacetanilide, exists in white-green or brown colour solid state. The density of p-Nitroacetanilide is 1.34 g/cm3. It is soluble in water at room temperature but insoluble in cold water. The melting point of the compound is 215°C (419°F or 488K) and the boiling point is 408.9°C (768.0°F or 682.0 K).

Figure 1 − Structure of p-Nitroacetanilide

The chemical formula of p-Nitroacetanilide is $\mathrm{C_{8}H_{8}N_{2}O_{3}}$ with IUPAC names of − n-(4- Nitrophenyl) acetamide, p-Acetamidonitrobenzene, and n-Acetyl-4-nitroaniline. The treatment of Acetanilide with a mixture of nitration reagent i.e., Sulphuric acid and Nitric acid, results in p-Nitroacetanilide as the product.

Aim of the experiment

The experiment aims to form p-Nitroacetanilide applying nitration reaction to the compounds: Acetanilide and Acetic acid.

Theory

Treatment of acetanilide with a nitration mixture consist with Nitric acid and Sulphuric acid results in formation of o-Nitroacetanilide as the minor product. The product is highly soluble in alcohol and can be isolated easily by crystallization. The chemical reaction of preparation of p-Nitroacetanilide using nitration of acetanilide is shown below.

Figure 2 − Electrophilic substitution reaction

P-Nitroacetanilide does not has any smell and ise prepared from Acetic anhydride with Aniline. The product compound has chemical formula of $\mathrm{C_{8}H_{8}N_{2}O_{3}}$. The compound generally shows several analgesic features that are widely utilized in pharmaceuticals.

Materials required

Some essential equipment and compounds are required for the completion of the experiment are listed below −

• Acetanilide

• Dropping funnel

• Fuming Nitric acid

• Filter paper

• Glass rod

• Concentrated Sulphuric acid

• Buchner funnel

• Conical flask

• Pipette

• Beaker

• Ethyl alcohol

Procedures

The procedures for preparation of p-Nitroacetanilide are mentioned below −

• 3 g of acetanilide powder is taken in a clean beaker. The powder is mixed with glacial Acetic acid in the beaker by stirring it at room temperature.

• The solution is heated to dissolve Acetanilide completely.

• Once mixture is cool down, concentrated Sulphuric acid is added to the mixture and kept undisturbed in an ice bath.

• Fuming Nitric acid is added drop wise to the chilled solution with the help of a dropper or dropping funnel.

• The temperature during the experiment is kept below 20°C.

• 100 g of crushed ice is then added to the beaker and stirred well in order to form large crystals of p-Nitro acetanilide.

• The filter paper is used to filter the crystals of the compound from the solution. Ethyl alcohol is also used to get crystals of p-Nitroacetanilide.

Observation

The reaction of electrophilic substitution shows that electrophile -$\mathrm{NO_{2}^{+}}$ will remain attached in the para position as -$\mathrm{NHCOCH_{3}}$ group helps to concentrate cloud of electrons at ortho and para position in Benzene ring. The reactions also highlight the oxidation of amino groups using nitration reagent

The oxidation of amino group is protected by nitration of acetanilide at first and then hydrolysis of p-Nitroacetanilideto form p-Nitroaniline. Direct Nitration of Aniline is not possible due to very fast oxidation reaction of amine group. Two major isomers of the product are seen as2-Nitroacetanilide and 3-Nitroacetanilide. The molecular mass of the component is 180.16 g/mol.

Precautions

The major precautions or safety measures that can be taken during the experiment are stated below −

• The temperature during the experiment must not enhance more than 20°C.

• Nitric acid is generally added to the solution of the reaction when the mxture is immersed into an ice bath.

• Fuming Nitric acid is added dropwise to the mixture of reaction.

• The fumes of Nitric acid must not be inhaled during the experiment and safety gloves must be used.

• After completion of the experiment, the disposable or waste materials must be thrown in a prepared place to avoid health hazards.

Conclusion

Nitration of acetanilide results in formation of p-Nitroacetanilide. Recrystallization of p- Nitroacetanilide will takes place after completion of the experiment. Nitro based organic compounds are highly used as a primary substance for several materials with commercial benefits. The materials include dyes, pills, explosives, and so on.

FAQs

1. What are the methods through which p-Nitroacetanilide recrystallized?

Nitration of Acetanilide is a famous method for preparation of p-Nitroacetanilide after effective treatment of nitro compounds. The primary product is ortho directing compound .and Ethyl alcohol is used for crystallization of p-Nitroacetanilide

2. What are the major properties of P-Nitroacetanilide?

P-Nitroacetanilide consists of yellowish granular powder in solid state. The colour of the compounds can also be brown-green or green-yellow depending on their preparation pathways. The melting point of p-Nitroacetanilide is 215°C and the boiling point is 409°C

3. What are the uses of p-Nitroacetanilide?

P-Nitroacetanilide is widely used in the pharmaceutical industries due to its analgesic features. The compound usually is used in the production of paracetamol medicines, poultry, anti-oxidants, gasoline, pesticides, and rubber chemicals.