Tuesday, July 17, 2012

How to make ammonium perchlorate : electrolysis

As I told you earlier, ammonium perchlorate (AP) is not available in all countries.
Here is a way to make it.

First, AP is made by electrolysis of a solution of sodium chloride (table salt or NaCl).
Electrolysis is made by plunging 2 electrodes (an anode and a cathode) in an electrically conductive solution called electrolyte and plugging these electrodes to a power supply.

The electrolysis of NaCl results in the production of chlorine (Cl) and soda (NaOH). After a number of complex chemical and electrochemical reactions occurs as the chlorine dissolve in the solution.

This will yield sodium chlorate (NaClO3) if you have choose to use sodium chloride in your electrolyte, you can use potassium chloride (KCl) and you will have potassium chlorate (KClO3).
But KClO3 solubility is very low compared to NaClO3 so that it will precipitate out of the solution.
Not good for making perchlorate as the chlorate needs to be in solution in order to be electrolyzed in perchlorate.

NEVER USE AMMONIUM CHLORIDE (NH4Cl) in the electrolyte because the resulting salt ammonium chlorate is very instable though very dangerous.

Now that the sodium chlorate is made, let run the electrolysis. The chlorate will be electrolyzed to the corresponding perchlorate.

Once the electrolysis done, there is sodium perchlorate in the electrolyte. To obtain ammonium or potassium perchlorate, we will use what is called a double decomposition.
Introduce, either ammonium or potassium chloride in the solution and the corresponding salt will precipitate out as their solubility is very low compared to sodium perchlorate. To finish, extract the perchlorate and let it dry in the sun.

This post was the process of making the perchlorate, further post will cover the details like the electrode's materials (very important) and recycling the solution.

3 comments:

  1. How much ammonium would need to be introduced per oz of sodium perchlorate solution.

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    1. Thanks for your interest.
      To answer you, you would need a stoichiometric amount of ammonium, or in non-chemist terms for 1 g of sodium perchlorate, you add 0.5 g of ammonium chloride.

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    2. Thank you for your response.
      I also have three more question 1st. what would be the most efficient way to extract the ap, 2nd. Does the electrolysis cell need to be enclosed, 3rd. what should the run time be for a 64 oz solution (how much power should i put into the cell).
      Thanks for your help.

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