22 replies to this topic

[Arthur Brown]

You really need a quantitative method (and chems and equipment) to prove the degree of conversion from chlorate to perchlorate. Only when you can start with 90+% perc should you destroy to purify. I think the perc thread started by member Lord Dranack had the quantitative method. Alternatively search Vogel Quant, Inorg. analysis. The Cape canaveral site has methods for determining the end point and the current efficiency of a cell. Have you calculated the cell performance in terms of current time and grammes?

[Gary]

You really need a quantitative method (and chems and equipment) to prove the degree of conversion from chlorate to perchlorate. Only when you can start with 90+% perc should you destroy to purify. I think the perc thread started by member Lord Dranack had the quantitative method. Alternatively search Vogel Quant, Inorg. analysis. The Cape canaveral site has methods for determining the end point and the current efficiency of a cell. Have you calculated the cell performance in terms of current time and grammes?

The difficulty with this is that I do not possess the equipment required to carry-out a quantitative analysis of my sodium (perchlorate?!). Namely, a burette and volumetric flasks so that I can make-up standard solutions of known concentration. Would anyone know where I can buy such equipment?

[digger]

The difficulty with this is that I do not possess the equipment required to carry-out a quantitative analysis of my sodium (perchlorate?!). Namely, a burette and volumetric flasks so that I can make-up standard solutions of known concentration. Would anyone know where I can buy such equipment?

Pretty much any lab supplier will sell you glass ware, however it does come up on ebay as well at reasonable prices for second hand stuff.

D

[Arthur Brown]

Ebay will supply the glassware, a local lab supplier will supply the reagents, You must supply the skill to determine the analytical method and apply it to the solutions of the process. Get yourself a copy of Vogel Quantitative inorg analysis. Perc has few incompatibilities (if any) but the likely contaminant -chlorate- has big bad incompatibilities sulphur etc

You really do need to prove the purity of the product before you can have confidence in its safe use.

http://www.abebooks....ative inorganic

May assist you to keep your fingers attached! For £10 ish there is nothing to beat the real text. The advantage with an old book is that the methods are wet chemistry based and need only a few hundred pounds to do accurately. Modern methods usually need a multi million pound machine! They do it faster and possibly better but much more expensively!

[digger]

Ebay will supply the glassware, a local lab supplier will supply the reagents, You must supply the skill to determine the analytical method and apply it to the solutions of the process. Get yourself a copy of Vogel Quantitative inorg analysis. Perc has few incompatibilities (if any) but the likely contaminant -chlorate- has big bad incompatibilities sulphur etc

You really do need to prove the purity of the product before you can have confidence in its safe use.

http://www.abebooks....ative inorganic

May assist you to keep your fingers attached! For £10 ish there is nothing to beat the real text. The advantage with an old book is that the methods are wet chemistry based and need only a few hundred pounds to do accurately. Modern methods usually need a multi million pound machine! They do it faster and possibly better but much more expensively!

We have the multi million pound machines at work (well about 30K for a GC or NIR more for auto samplers etc), but I have to say they do go wrong and when I ask for a test to be done on something out of the norm it can often give a result which makes me ask them to check the machine result with a wet method and guess what the machine methods can be inaccurate esp. when the base line is not obvious on the trace.

So I agree wet methods are definitely valuable (and the only option for all but the richest the amateur chemist) and offer excellent checks for the fancy dangle machinery (even if some of the wet methods can involve some pretty nasty reagents)

[Mumbles]

Should you want to remove the sulfate, etc, just recrystalize it. Potassium Perchlorate has an incredibly low solubility near freezing, so you will get a pretty good return. Potassium sulfate wont hurt too much, but it's unlikely any will be formed. The nice thing with the ferrous sulfate route is that you can judge elimination of the iron by the color of the crystals. The iron salts are colored green (ferrous) and red/brown (ferric).

You could also add a drop of Potassium Thiocyanate to a sample solution of the perchlorate. It will imediately turn dark red if any Iron (III) is present. This does add another chemical to the list though.

[cafedebrasil]

To destroy your Chlorate, add concentrated HCl to the Chlorate/Perchlorate Mix. The HCl will react with Chlorate, forming Chlorine dioxide, a yellow, toxic and slightly explosive gas. So be sure to do this outside an in small quantities!. The Perchlorate does not react with HCl.

[tentacles]

It feels kind of useless, but I'll add my two cents:

First, convert your sodium salt to the potassium salt. Now you'll have a product that is easily separated in bulk from the chlorate by recrystallization. First of course, separate the potassium salts from the sodium as best you can in a single step. Now recrystallize the potassium chlorate/perchlorate mixture, and take the product of that operation, dissolve in boiling water until saturated, and at this point would be a good time to use chemical means to destroy any residual chlorate, which will be a small, but detectable, amount. Cool the solution, collect the crystals, etc and somewhere near this point you should have clean perc. The number of recrystallizations may vary, though. Experimentation is NECESSARY. The problem I see with using sodium salts is removing all those pesky sodium ions. That's not easy, and adds a LOT of work.

There's no substantial need for things like pipettes and volumetric flasks - it's far easier to make up a solution that you can compare to, see the link in the next paragraph. Why titrate when you can test against a known level, easily (and cheaply) made up in bulk?

For a good, easy chlorate test you need a reagent called N-Phenylanthranilic Acid - it's mentioned on the wouter pages, and possibly also dann2's pages (the geocities site). If you look here (http://www.apcforum....hp?showentry=20) Swede has refined greatly the usability and sensitivity of this test. His test on commercial perc yielded absolutely no color. Undetectable level of chlorate. He was able to detect 10ppm levels in other tests.