Question

What is the purpose of the following in the experiment for Nitration of Methyl Benzoate and what is the reaction scheme for the experiment

1. Sulfuric Acid

2. Methyl Benzoate

3. Nitric Acid

4.Ethanol

Answer 1

1) sulfuric acid help in the formation of nitronium by reaction with nitric acid.

2) Methyl benzoate is the reactant in the reaction which is most useful for a reaction . it will lead to the formation of product .

3) Nitric acid react with sulfuric acid and lead to the formation of the reacting reagent or an electrophile that is nitronium ion.

4) Ethanol act as a solvent which provides medium to the reaction.

Reaction scheme for experiment :-A 1.0 mL sample of conc. Sulfuric Acid is placed in a clean, dry 6" Test Tube and cooled to about 0°C. by swirling in an ice bath. Methyl benzoate (0.7 mL.) is then carefully added. The mixture is shaken to produce one layer. The solution is continuously cooled at 0°C.In a separate 6" Test Tube, prepare a mixture of 0.4 mL of conc. Nitric Acid and 0.4 mL of conc. Sulfuric Acid. Cool this mixture to 0°C.Using a Pasteur Pipet, add the cold mixture of acids drop by drop to the cold solution of the ester in sulfuric acid. Continuously swirl the ester solution in the ice bath as you add the mixture of acids. Keep the temperature of the reaction at about 0°C throughout the reaction! This should take 5-10 min.After the mixed acids have been added, swirl the Test Tube in the ice bath for another 5-10 minutes. Finally, allow the reaction mixture to stand at room temperature, with occasional swirling, for another ten minutes.Fill another 6" Test Tube about two-thirds full with crushed ice. Slowly add a drop or two (Pasteur Pipet) of the reaction mixture onto the ice with swirling. Once crystals of the product begin to form, slowly add the remainder of the reaction mixture, dropwise with swirling. Allow the ice to melt.Collect the solid material by suction filtration on a Hirsch Funnel. Carefully rinse the solid on the filter with 0.5 - 1.0 mL of cool tap water to remove traces of acid.Chill about 0.5 mL of 95% Ethanol to about 0°C. Use this "ice-cold" ethanol to carefully wash the solid on the filter. Draw air through the solid to hasten the drying process.When dry, determine the weight and melting range of the solid. This is the "crude Yield". The solid can be recrystallized from 95% Ethanol. The recrystallized material is your "Purified" Yield. Determine its weight and melting point.