Question

** synthesis of p-nitroaniline

Based on the melting point of the recrystallized product, can you verify that the major product of the reaction was indeed p-nitroacetanilide?

If you were to perform a TLC analysis of your crude product, how would you know if some of your product had undergone hydrolysis? (Hint: How many spots might you see, and what might their Rf values indicate regarding their polarities? Refer to your answer to Pre-Lab Q 4b)

In which region of the ¹H NMR spectrum would you look for evidence that the nitration reaction had occurred as expected? Explain. (Hint: which part is expected to change?) Look up the spectra for these compounds online.

Answer 1

Based on the melting point of the recrystallized product, we cannot able to verify that the major product of the reaction was indeed p-nitroacetanilide.

Instead, both crude and recrystallized product will be analyzed by thin layer chromatography (TLC) to verify the major product as below

We will now do a TLC analysis of our crude reaction material and our recrystallized material. We will also spot two standards, pure para-nitroaniline and pure ortho-nitroaniline.

Then the crude reaction material will show two spots corresponding to both para-nitroaniline and ortho-nitroaniline.

The recrystallized material will shows only one spot corresponding to para-nitroaniline, which indicating that the major product of the reaction was p-nitroaniline.