Sciencemadness Discussion Board

Zinc removal without altering the pH

scrumpyjack83 - 11-12-2011 at 10:26

I am trying to make Diethyl-p-phenylenediamine sulfate from Diethylaniline. I have nitrosated Diethylaniline and performed reduction reaction by Zn/H2SO4. However, I am not able to isolate the reduced product. Technically, Zinc Sulfate poses as interference. Can sumone pls help me eliminate Zinc Sulfate from the solution withour altering the pH?

Adas - 11-12-2011 at 10:34

Add calculated amount of NaOH to just neutralize the diethyl-p-phenylenediamine (but not ZnSO4), wash it with water and filter it. Then add H2SO4 to make the sulfate. This should work.

Nico - 11-12-2011 at 10:36

If I am understanding your problem properly, you should now have the hydrochloride of your amine as well as the zinc sulfate in your solution. I would rather change the pH than maintain it, so that you get the free amine which you can subsequently extract with diethyl ether or MTBE.
Nontheless, it seems that you've already considered this way of upworking you crude product, so could you narrow down the type of interference the zinc sulfate effects, please ?