Sciencemadness Discussion Board

Greetings and Question on Chlortaes/Perchloraes

phys_geek - 31-8-2020 at 00:42

Hi everybody,

It is my pleasure to be in this very exciting forum and I hope my primitive questions will not take too much of your time since I am not a chemist.

There are lots of threads regarding conversion of chlorates to perchlorates and I wanted to ask if there is anyone who has done according to US2853362A.

I did not post the link(perhaps it is against the rules of the forum) but would it be ok to use lead dioxides from car batteries or it will be to impure to do that? Is yield worth of doing it? what about potential hazards?

It also mentions parts as units of measurements but I am not sure if it is by weight or volumes.

Sorry about too much questions with hesitation. I consider myself way below average in chemistry lab since I am a graduated of physics. (Hope we are not hated here lol).

Any advice will be greatly appreciated.

markx - 31-8-2020 at 02:24

Welcome to the forum!

The proposed method of conversion seems at first glance rather impractical for a hobbyist setting. Laborious and involving lead salts+strong acids that present a hazard when spilled or accumulated. I would also not suggest to try and regenerate the lead dioxide by means of chlorination as per instructions in the patent. For curiocity's sake you can try the conversion at small scale to verify if the approach is valid. Lead dioxide from car battery can be is usually quite pure since contaminants inside the battery shall not do any good in terms of prolonging the life of the device.

But perhaps the alternative method of thermal decomposition of pure potassium chlorate (yielding KCl and KClO4) might offer a more convenient way of conversion. Since you are well versed in physics then it should not be a problem to build an electrical temperature controller for the decomposition reactor. The decomposition shall yield only potassium chloride (and partly oxygen gas) as the byproduct. It is harmless and easily separated from the low soluble potassium perchlorate. And no messing around with lead compounds. Also no acids.....just temperature and time. Granted, the yields shall not be super impressive, but the simplicity and lack of inconvenient byproducts might make up for it.
It depends on what scale you wish to operate with the process: on small scale the thermal decomposition approach makes sense, but if you desire a more sizeable amount of product then electrosynthesis is the way to go. A cell with graphite or mixed metal oxide anode for the conversion of chloride to chlorate, followed by another run in a cell with a plantinum anode to further convert the chlorate into perchlorate.

There are loads of threads on this board dealing with the topic of producing chlorates and perchlorates in amateur lab settings. Feel free to rummage through them and ask questions when they arise.

B(a)P - 31-8-2020 at 15:21

I have not tried lead dioxide, but I have had good success both via the decomposition method described by @markx and using a platinum anode. There is a lot on this forum about lead dioxide anodes. Try this thread

If it is the sodium salt that you have, when it comes time to purifying your product this can be done with acetone. @Laboratory of Liptakov made a great video about this.

phys_geek - 2-9-2020 at 04:57

Thanks guys a lot for your helps.

I am aware of those two techniques and am thinking of implementing them later. The reason for starting this thread,besides introducing myself, was that I was not very confident to work with molten Chlorates(besides their low yields) and the difficulty of choosing appropriate path for the electrolysis(specially since there were lots of links related to electrode vendores that were either broken links or reported as fake).

Dear markx, may I please update that I have access to an acceptable lab (not very professional thu) in my workplace and I am by law allowed to purchase required materials and equipment if they are not very expensive. Does this change your mind on the ease of doing this process for a beginner like me?

I also have the honor of working with concentrated Sulfuric Acid but still scared of that.

I am not debating of course and simply trying to describe my condition better for experinced individuals like you to give a suited instruction. Hope you will not perceive it as complaining.

markx - 3-9-2020 at 05:06

By all means try out the conversion method and let us know about the outcome :) And if you do not succeed with the first try, then try again. No better teacher than practice. If you don’t start somewhere then how will you become experienced. Remember to use common sense regarding safety and get at it. Work on small scale to minimize cost and risk and just have fun.

Maurice VD 37 - 3-9-2020 at 08:00

The disproportionation of sodium chlorate is reported in a publication by F. Solimosy : The Thermal Stability of Chlorine Oxysalts in the Solid state, Acta Chimica Academias Scientarum Hungaricae, Tomus 56 (4), P. 337 - 355 (1968).
The reaction is : 4 NaClO3 --> NaCl + 3 NaClO4.
They show that no reaction occurs under 400°C.
At 400°C, after 2 hours heating, the yield of the reaction produces 4.51 % NaClO4.
At 410°C, after 2 hours heating, the yield of the reaction is 6.20% NaClO4
At 420°C, after 2 hours heating, the yield is 11.4 % NaClO4
At 430°C, after 2 hours heating, the yield is 23.6% NaClO4
At 440°C, after 2 hours heating, the yield is 50.8% NaClO4
At 450°C, after 2 hours heating, the yield is 66.2% NaClO4, but some bubbles of oxygen are released
At 460°C, after 1 hour heating, the yield is 45.2% NaClO4, but 0.3% of NaClO3 is decomposed in O2 by hour

There are no data about potassium chlorate.

symboom - 3-9-2020 at 10:51

The thermal process of sodium chlorate to perchlorate

[Edited on 3-9-2020 by symboom]

AJKOER - 5-9-2020 at 04:30

The comment "There are no data about potassium chlorate" may suggest it is wiser to work with the sodium salt over the potassium one, as even a trace of impurity, in the latter, may result in a much more energetic outcome.

Note also, heating should take place in an open (not closed) vessel.

phys_geek - 8-9-2020 at 00:16

I thank everybody for the inputs and thoughts.

No truer words have been said markx than yours. I absolutely agree and I am a man of action and will be able to write and share my experiences in a couple of days since the lab I mentioned is under some minor constructions.

Most of you are mentioning Sodium Chlorate which,where I live, is probably non-existent. I doubt I will be missing too much if I do by potassium chlorate.

Anyway please give me some time so that I can finalize my attempts and write my results.

Thanks again fellas

MidLifeChemist - 9-9-2020 at 14:20

Welcome to the forum, and good luck with your conversion of Chlorate to Perchlorate

Antiswat - 2-10-2020 at 22:18

i think one might be able to use sodium silicate solution to get PbO2 to adhere to something might work, it basically ends up forming glass when its dried out, unsure if you need to heat it up too, now if you could make that porous that would be really interesting

if youre working with chlorate to perchlorate its ideal to go with sodium and then later convert that into potassium

i recall something about ferrate theoretically being capable of turning chlorate into perchlorate in solution but its very unstable so i dont think it has been attempted before. you can buy 25kg bags of "ferrate" on alibaba though

i think if you mix up sugar or some other organic compound that decomposes under heating with sodium silicate solution and a heap of PbO2 you might get something that could actually work, maybe the holes in the electrode would have to be more systemic so the gasses formed doesnt crack the whole construction apart, looking up sodium silicate and waterglass electrode i dont get anything so i dont think this has been attempted before, easiest way to make sodium silicate is to get silicon dioxide (glass) kitty litter, it dissolves rather easily with sodium hydroxide, and when i made it i would usually find a big plate of gelled up sodium silicate on the bottom, essentially some ugly grade of aerogel