Question

1. Explain why the nitration of methylbenzoate occurs in the meta position

2. Why is it important to a synthesis reaction of m-nitromethylbenzoate mixute to be cold?

3. What is the function of sulfuric acid in this synthesis

These are the procedures for reference

Procedure:

1. Add concentrated Sulfuric acid to a conical vial (CV) to the 0.3 mL line. Perform in a fume hood.
2. Cool the CV in an ice bath to 0-10 ^oC and then add 0.140 mL of methylbenzoate. Add a spin vane.
3. In a small test tube prepare a mixture of 0.1 mL of cold conc. Sulfuric acid and 0.1 mL of conc. Nitric acid (add cold sulfuric acid to cold nitric acid).
4. After both solutions have cooled to 0-10°C add the nitric-sulfuric acid to the CV with a disposable pipet. Stir to mix the solution completely.
5. Maintain the temperature between 5-15 ^oC for approximately 5 min.
6. Warm to room temperature - approx. 15 min.
7. Pour onto 1 g of ice in a 10 mL beaker.
8. Stir and allow the product to solidify.
9. Collect on a Hirsch funnel and wash with water. Rinse with a few drops of ICE COLD methanol. Use as little methanol as possible.
10. Recrystallize the product from an equivalent weight of methanol.
11. Calculate the theoretical and experimental yields.
12. Calculate the percent yield.
13. Run a melting point and an FTIR spectrum. Locate the two peaks in the IR characteristic of the NO₂ group to confirm the reaction.

Answer 1

01. The nitration of methyl benzoate occurs at the meta position because

During the reaction the resonance structure creates a positive charge at ortho and para position of methyl benzoate. This is due to ester group in methyl benzoate which is electron withdrawing .

NO₂ group is meta directing and attaches itself to the meta position in this Cass so we get m- nitro methyl benzoate in this reaction.

02. Why is it important to a synthesis reaction of m-nitromethylbenzoate mixute to be cold?

It is important during the synthesis of m-nitromethyl benzoate to keep the mixture cold because heat is generated in this reaction and hence excess of heat can lead to the formation of ortho or para products in this reaction

Since we only want meta product we keep the mixture cold

03. What is the function of sulfuric acid in this synthesis?

Sulfuric acid is used as a dehydrating agent in this experiment

When we mix the HNO₃ ans sulfuric acid nitronium ion is formed which is used for the nitration in the further reaction.

Sulfuric acid helps to remove water molecule from nitric acid and acts.as a dehydrating agent.

I hope this helps if you have any query or want more detailed explanation feel free to ask in the comment section below.