[mana]

Hi all
I have tried to synthesis 4-nitro aniline from 4- nitro acetanilide according to procedure below:

100 g of 4-nitroacetanilide is boiled with 250 ml of 25 % sulfuric acid in a round flask attached to a reflux condenser until 4-nitroaniline completely dissolves. The clear solution is poured into a beaker, and the free 4-nitroaniline base is precipitated by adding dilute sodium hydroxide solution till alkaline.
 
but when I added the clear solution into water I saw  participation without adding NaOH, now I doubt that participate is 4- nitro aniline or not? 
and also when I tried to repeat the according procedure, I obtained the clear solution but it didn't participate after water addition nor NaOH addition either
what has happend?

[OrganicDan96]

you could probably make 4-nitroaniline by hearing 4-nitroacetonilide with methanolic KOH. then precipitate with water. 

[wildfyr]

I bet this is a lab report and so he needs an explanation of the mistake, not alternate path. And this reaction is usually done using acid (personally prefer HCl, it's less aggressive).

Could adding the wrong solution at any point explain this OP?

[mana]

I bet this is a lab report and so he needs an explanation of the mistake, not alternate path. And this reaction is usually done using acid (personally prefer HCl, it's less aggressive).

Could adding the wrong solution at any point explain this OP?

yes my explanation for the procedure is a lab report, I'm sure that I didn't add any wrong solution, is it possible that when I add water to reaction solution the mixture pH increases and the 4-nitro aniline participation occurs?

[wildfyr]

No, adding water to a strongly acidic solution will not change the pH much.

I don't mean to be insulting here, but the chemistry of a simple acetylysis is more dependable than any human being's recollection of what they did, especially when you ran the same reaction twice and got different results.

Here is an important factor, often when adding base to strong acid, people will check the pH before it is truly mixed, and get incorrect answers from their pH strips. I've done this several times by mistake. The strip will say it's basic becuase that top layer was basic, but really the full solution is still quite acidic when fully homogenized.

Also, don't you check your product by FTIR?

[mana]

Also, don't you check your product by FTIR?

No, I just wanted to understand what has happened before spectroscopic analysis (because of limited
facilities).
on the other hand I had to heat my reaction mixture with a lab mantel, and may be my Unrepeatable results is due to using that non standard mantel