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Author: Subject: Ir in perchlorate cell
dann2
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[*] posted on 9-4-2009 at 07:38


Nice on Formatik,

Unfortunately Google books only lets American IP numbered veiwers.
You need to use a proxy server if elsewhere.
Try here
http://www.publicproxyservers.com/proxy/list1.html

TIA,
Dann2

[Edited on 9-4-2009 by dann2]
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Formatik
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[*] posted on 9-4-2009 at 17:33


True, they will block at least certain countries, so I've just attached the file below. Although chlorate reaction with acid is inferior to chlorate fusion, which in turn is inferior to chlorate eletrolysis as far as yields go, there is at least one advantage and that is time and ease it has over both of those methods.

Attachment: The_Preparation_of_Potassium_Perchlorate.pdf (777kB)
This file has been downloaded 668 times
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JohnWW
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[*] posted on 9-4-2009 at 18:10


Quote: Originally posted by dann2  
Unfortunately Google books only lets American IP numbered viewers. You need to use a proxy server if elsewhere. Try here: http://www.publicproxyservers.com/proxy/list1.html

There are other sources of proxy-servers, including of ones based in the U$A; in particular: http://www.samair.ru/proxy
Most of them are in universities, and are usually intended to be private ones but their details have "leaked out", with the result that they seldom last longer than a few days or weeks.
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dann2
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[*] posted on 13-4-2009 at 11:57


Hello,
Patents US 2,489,571 to US 2,489,575 are on a similar theme to above.
US 2,489, 571 attached.
Dann2

Attachment: US2489571.pdf (1.2MB)
This file has been downloaded 495 times

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[*] posted on 23-4-2009 at 09:43


Thanks, the google book states that perchlorate could also be produced with UV activated oxigen, donĀ“t think this could work with my UV-LED.
But the H2O2 in acid method could be from interest.
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Formatik
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[*] posted on 23-4-2009 at 10:50


Gmelin also says UV-activated oxygen acting on chlorate forms perchlorate, O3 also, but these two in lesser extent than oxidizing chlorate with persulfate. Another pretty good book about perchlorates is Perchlorates: http://www.archive.org/details/pwechloratesthei001740mbp It covers electrolysis in specific when it comes to preparation, though iridium isn't mentioned. But it mentions and cites with reference the search of Pt substitute anode, among which have been tried: W, Mo, Si, graphite, magnetite, MnO2, PbO2. They say out of those, only PbO2 proved valuable in perchlorate manufacture.
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[*] posted on 24-4-2009 at 14:02


I have attempted conversion of chlorate to perchlorate with bubbled ozone. 24 hours of bubbling O3 through perhaps 200 ml saturated potassium chlorate yielded only the faintest traces of perchlorate, but it was undoubtedly there, tested with methylene blue; there was also solid perchlorate which ultimately jammed the tube.

But the problem with non-traditional methods - there is no escaping the fact that in any appreciable quantity, it takes a lot of energy, chemical or otherwise, to convert. A large hobby cell takes dozens of amperes for days to convert a kilogram. To use ozone would require an exceptionally powerful ozone generator and probably a specially-built mixing device for best contact.

Potassium peroxymonosulfate might be a player. It is OTC at pool stores. Not cheap, but it would be interesting to investigate chemical means to oxidize chlorate to perchlorate.
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Formatik
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[*] posted on 24-4-2009 at 21:50


Perchlorates mentions the oxidation of chlorate by persulfate albeit, only briefly. It also briefly touches on some method proposed by Ehrhardt during WWII employing PbO2 in H2SO4 to oxidize chlorates to get perchlorates in high yield. Because of regenerative and economic aspects of the method, it has remained burried in the literature.

For the persulfate oxidation, Gmelin gives the following citations (none of which I've found so far): Bennett, Mack (Trans. Am. electrochem. Soc. 29 [1916] 323; Chem. Eng. 23 [1916] 200; C.A. 1916 2327) and Mack (J. phys. Chem. 21 [1917] 238; C. 1921 III 765).

Peroxomonosulfate has less oxidation potential than peroxodisulfate, so it might not work. But, it could also work, since PbO2 (or BaO2, Na2O2 under strong cooling) react with conc. H2SO4 to form H2SO5. Though KMnO4 or Na2O2 in aq. solution have been tried and found not to oxidize chlorates.

As to the oxidation by ozone, it may be more complex than bubbling ozone in alone. Both of the references by Mack and/or Bennett will have more about that. Since they are the ones who had claimed O3 can have the ability to oxidize ClO3- to ClO4-. Perchlorates states this: "Under certain conditions, ozone will produce a small amount of perchlorate from chlorates, but much of the work thereon is inconclusive, and such a process is seemingly very inefficient."

Before trying out either a process similar to the Ehrhardt process or Bennett and Mack's persulfate oxidation, I think it would be crucial to get the original references. Without being familiar with any of it, the former process sounds quite dangerous outright.

[Edited on 25-4-2009 by Formatik]
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[*] posted on 18-1-2010 at 06:24


Hello,

Since there was some discussion of making Perchlorate here (using Chlorate and Oxidizer) I thought I would plonk this paper (Part B) here.
It describes attempts at Perchlorate manufacture using acids and Chlorate. Has not been uploaded before............I think.

Paper too big, link to here:
http://handle.dtic.mil/100.2/AD024116

There is a part A giving details of using Silicon Carbide Anodes that I have not got.

Dann2
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[*] posted on 18-1-2010 at 06:34


Another weird and wonderful report here:
http://handle.dtic.mil/100.2/AD016814

VI. CONCLUSION
A. PART I. PREPARATION OF CHLORATES
1. A survey of all known processes for producing chlorates chemically
and without 2lectricil;/ shows that good chemical methods, by modern
standards, have been discovered and used already on a commercial
scale. The best of these is the Liebig process for producing KCIO3.
A cost estimate of this process is included in the supplement.
B. PART II. PREPARATION OF PERCHLORATES
1. There is no chemical process to our knowledge which can compete
economically with the present electrolytic production of perchlorates.
Our efforts to develop such a chemical process have been
testing chemical reagents which might oxidize chlorine compounds
to perchlorates.
2. The chemical oxidants considered and tested were hydrogen peroxide,
potassium superoxide, persulfuric acid, potassium persulfate,
potassium chlorate, sodium chlorate, chlorine, ozone, pressurized
oxygen, ^\nd lead dioxide. In most cases the yield of perchlorate
is very low, or none.
[
3. The least costly of the various processes proposed are those using
chlorates, ozone, and lead dioxide as oxidants respectively. Additional
studies are planned for the development of each of these
oxidants.
k. Many more oxidants are to be considered, but none show promise of
producing perchlorates at less than twice the present market price
of electrolytic chlorates.
S. There are not enough data at present to build a working pilot plant
for perchlorate production by means other than electrolytic.

CONFIDENTIAL

DANN2
(you did'nt get this from me)

[Edited on 18-1-2010 by dann2]
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[*] posted on 19-1-2010 at 08:09


Searching the web for the Liebig chlorate process yielded mostly condensers and other N/A material. Liebig was a busy guy, for sure. Can someone summarize it (very briefly)?

I am not surprised that there is not a chemical oxidation process that is economically viable for perchlorate. I mentioned the use of Ozone in a small test setup to produce trace perchlorate, but with the low output of my ozone rig, it would take months to make a few grams. Scaling up and increasing the power of the process is going to be expensive, and the electricity typically consumed to make O3 is going to probably exceed the electricity used in the electrolytic process.

It would be nice to stoichiometrically add a persulfate to chlorate and have fat perc crystals pop out, but it isn't going to be that easy!
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