making potassium (per) chlorate

[markx]

Has anyone ever made AP before? I made it by reacting sodium perchlorate with ammonium chloride, but after a few days it turned yellow and released maybe chlorine gas. I'm very confused.Please give me some advice.

Most likely impurities are the cause of the decomposition that you observed. Perhaps your perchlorate batch was contaminated by chlorate and it began to decompose after having partially formed ammonium chlorate....

Also metallic impurities in the form of ions (from your chloride source or reaction vessel) can catalyse several redox systems that may lead to decomposition of oxyhalogen moieties.

[Japanese]

Most likely impurities are the cause of the decomposition that you observed. Perhaps your perchlorate batch was contaminated by chlorate and it began to decompose after having partially formed ammonium chlorate....

Also metallic impurities in the form of ions (from your chloride source or reaction vessel) can catalyse several redox systems that may lead to decomposition of oxyhalogen moieties.

Thank you! As you say, I neglected to destroy chlorate. Next time I will use hydrochloric acid to destroy it and try again.

[WSM]

When I made potassium perchlorate, I destroyed residual chlorate in the sodium perchlorate by introducing sodium metabisulfite solution, deep under the surface of the sodium perchlorate solution, at a slow rate.

 

The metabisulfite breaks down to release sulfur dioxide which breaks down chlorates. Afterward comes the potassium chloride solution which quickly drops out potassium perchlorate powder from the mixed solutions.

 

I don't think it would work the same for AP, due to the relative solubilities.

 

WSM

[sefrez]

Basically a press for a chlorate cell lol.

 

I want to work with barium as well, though it's toxicity makes me think it'll be annoying to deal with safely. It's in a lot of star compositions. I also see dichromates used pretty often. I don't think I'd ever work with that stuff in powdered form.

 

Edit. Sorry, I was replying to an earlier post by wsm on clamping down the lid to his cell, and the talk about barium compounds. On my phone and in clicking the thread I must have been taken back to where I left off.

Edited August 11, 2020 by sefrez

[markx]

When I made potassium perchlorate, I destroyed residual chlorate in the sodium perchlorate by introducing sodium metabisulfite solution, deep under the surface of the sodium perchlorate solution, at a slow rate.

 

The metabisulfite breaks down to release sulfur dioxide which breaks down chlorates. Afterward comes the potassium chloride solution which quickly drops out potassium perchlorate powder from the mixed solutions.

 

I don't think it would work the same for AP, due to the relative solubilities.

 

WSM

AP can be made from sodium perchlorate and ammonium chloride, but the conditons and concentrations are rather specific. Just mixing arbitrary ratios of the reagents shall not yield a cristallised product due to the solubilities of all components being relatively high. Even done properly the yield shall suffer due to the part of AP that remains in solution. The industry applies a circular process for AP production from such starting materials and recycles the remnants of the previous batch into the next run to avoid loss of product due to the salt not being able to drop out from solution completely as is the case with KClO4. It was quite a complicated procedure that involved the boiling away of a certain amount of water from depleted solutions and separate stage for the removal of sodium chloride before the rest could be fed into the next batch.

I tried it on small scale and without proper preparations in single stage only....failed quite miserably

[WSM]

I think an effective method to make ammonium perchlorate from sodium perchlorate solution is to use ammonium oxalate as a reactant rather than ammonium chloride.

 

The benefit of using ammonium oxalate as a reactant is that the reaction produces not just AP but sodium oxalate, which drops out of solution, leaving the AP behind; a win-win in my view. The AP should be able to be recovered by carefully heating the solution to drive off the water. Some more research is called for, into the drying of AP safely.

 

With careful mixing, you can end up with both sodium oxalate AND ammonium perchlorate. I like that thought.

 

WSM

Edited August 15, 2020 by WSM

[pyrojig]

that sounds like a lot less mess to separate out of sol.

Oxalate is good for a number of other synths.

Chlorides are more difficult to get out of sol of water. very cold temps and multiple recrystallizations needed

[WSM]

that sounds like a lot less mess to separate out of sol.

Oxalate is good for a number of other synths.

Chlorides are more difficult to get out of sol of water. very cold temps and multiple recrystallizations needed

 

True!

 

I think that when the desired reactant is in liquid form, it's helpful if the secondary products completely drop out of solution, leaving only the primary product behind. Then you're only left with the job of drying it out (rather than having to purify it, too).

 

WSM

Edited August 19, 2020 by WSM

[WSM]

Basically a press for a chlorate cell lol.

I want to work with barium as well, though it's toxicity makes me think it'll be annoying to deal with safely. It's in a lot of star compositions. I also see dichromates used pretty often. I don't think I'd ever work with that stuff in powdered form.

Edit. Sorry, I was replying to an earlier post by wsm on clamping down the lid to his cell, and the talk about barium compounds. On my phone and in clicking the thread I must have been taken back to where I left off.

 

 

I'll put off the work with barium salts till I'm done with most of my standard chlor-alkali oxidizer manufacture research (a project for some future point in time).

 

The high temperature NaClO₃ cell support structure is much lighter duty than a press frame; more of a stabilizing framework. It keeps everything in place without stressing the glassware. It does provide a minimal amount of vertical pressure on the PTFE lid to help minimize any salt creep around the top edges of the cell.

 

WSM

[WSM]

I've managed to build the basic framework around the borosilicate reaction vessel with its PTFE lid assembly. Rather than use reversed Belleville washers (which would provide much more force than this setup needs), I used simple steel compression springs on the top of the all-thread rods for minimal force on the lid; and to accommodate any minor thermal expansion the system should experience by running at 110^oC.

 

I still need to add a few details to the system structure before building the cell's internal parts. I'll try to dust off my camera and add some photos for a clearer view of what I'm doing and how it's coming together.

 

I'm afraid it will look rather complicated by the time it's running, but the concept is fairly simple to begin with.

 

WSM

Edited August 23, 2020 by WSM

[WSM]

I've managed to build the basic framework around the borosilicate reaction vessel with its PTFE lid assembly. Rather than use reversed Belleville washers (which would provide much more force than this setup needs), I used simple steel compression springs on the top of the all-thread rods for minimal force on the lid; and to accommodate any minor thermal expansion the system should experience by running at 110^oC.

I still need to add a few details to the system structure before building the cell's internal parts. I'll try to dust off my camera and add some photos for a clearer view of what I'm doing and how it's coming together.

I'm afraid it will look rather complicated by the time it's running, but the concept is fairly simple to begin with.

WSM

 

 

I'm adding photos so you can see where this project is at.

 

 

 

There is more to do to make the final version of just the framework, let alone even getting the cell ready for a trial run; but one step at a time...

 

WSM

Edited August 23, 2020 by WSM

[Andead]

Quick question because I am struggling to find the answer to my question. When the titanium cathode has a layer of titanium dioxide how do i remove it? Using dilute HCL or acetic acid or are there some other options? Thanks

[WSM]

Quick question because I am struggling to find the answer to my question. When the titanium cathode has a layer of titanium dioxide how do i remove it? Using dilute HCL or acetic acid or are there some other options? Thanks

 

Experimentation might be called for. Possibly a timed soak in strong hydrochloric acid, followed by a thorough rinse in water might work.

 

If chemical means don't work, perhaps a mild abrasive would do the trick.

 

Let us know what you come up with.

 

WSM

[markx]

Soak in hot phosphoric acid is a pretty agressive means to clean Ti surface from deposits. Hydrochloric and acetic shall remove the hydroxide deposits from cathodes pretty quickly, but struggle with Ti compounds. There is really no practical need to remove cathodic deposits from Ti.....apart from aesthetic purposes. The oxide is permeable to charge transfer under cathodic potential and it will restablish its precence during the next use of the equipment anyways.

[WSM]

Soak in hot phosphoric acid is a pretty agressive means to clean Ti surface from deposits. Hydrochloric and acetic shall remove the hydroxide deposits from cathodes pretty quickly, but struggle with Ti compounds. There is really no practical need to remove cathodic deposits from Ti.....apart from aesthetic purposes. The oxide is permeable to charge transfer under cathodic potential and it will restablish its precence during the next use of the equipment anyways.

 

So the best solution to the problem is to ignore it? I like that.

 

If it works, great! If it doesn't work, you should know right away and use a different approach.

Try it and see...

 

WSM

Edited September 17, 2020 by WSM

[WSM]

I've managed to build the basic framework around the borosilicate reaction vessel with its PTFE lid assembly. Rather than use reversed Belleville washers (which would provide much more force than this setup needs), I used simple steel compression springs on the top of the all-thread rods for minimal force on the lid; and to accommodate any minor thermal expansion the system should experience by running at 110^oC.

I still need to add a few details to the system structure before building the cell's internal parts. I'll try to dust off my camera and add some photos for a clearer view of what I'm doing and how it's coming together.

I'm afraid it will look rather complicated by the time it's running, but the concept is fairly simple to begin with.

WSM

 

 

I did a quick calculation and if I use an anode sized 4" x 6" (roughly 100 mm x 150 mm) with two cathode plates surrounding the anode, the current draw would be about 93 Amps!

 

I need to figure out whether that's enough or too much current for a four liter volume (maximum) in my five liter reaction flask.

 

My purpose is to generate enough heat (but not too much) to run the system at 110^oC, where the excess water in the electrolyte will vaporize and get out through the vent, naturally concentrating the sodium chlorate electrolyte to where it will drop solid crystals out of solution when it cools to room temperature!

 

I'm not sure if I can easily determine this mathematically, or whether an empirical approach (make the electrodes up and try it in a cell) would work better?

 

We'll see...

 

WSM

Edited September 17, 2020 by WSM

[WSM]

After I posted about testing electrodes in a cell to measure the heat produced in the electrolyte, I realized how it could be done simply.

 

If I make up a temporary electrode assembly, I can immerse the electrodes in a large beaker of electrolyte to various depths and run the theoretical current while measuring the temperature of the electrolyte.

 

This seems to be the easiest method of determining the dimensions of the electrodes required to achieve the ideal temperature within the cell.

 

WSM

Edited September 17, 2020 by WSM

[markx]

After I posted about testing electrodes in a cell to measure the heat produced in the electrolyte, I realized how it could be done simply.

 

If I make up a temporary electrode assembly, I can immerse the electrodes in a large beaker of electrolyte to various depths and run the theoretical current while measuring the temperature of the electrolyte.

 

This seems to be the easiest method of determining the dimensions of the electrodes required to achieve the ideal temperature within the cell.

 

WSM

 

I do fear that in the end you might need to devise some kind of temperature control setup to keep the system balanced in the intended setpoint. The composition is going to change, the boiling point is going to change, the current is going to change and probably a myriad of other factors that I can not fathom. So this may very well be a rather complicated task to keep the the cell at the right temp range during the whole run just using fixed settings.

One approach I can see is to run the cell a bit overdriven and use a fan driven air cooling system set to 110C. Simple on off temp controller and sensor in/on the cell should suffice to aid with keeping the temperature in check. Air cooling can be quite effective and does not usually cause thermal shock that could damage the precious glass vessel. Also it is a good safeguard against mishaps as the conversion approaches final stages....I would not sleep very well knowing that a large potful of electrolyte is bubbling away hanging at setpoint just by a thread and good will

[Arthur]

It's very possible to support a reaction vessel in a large tank of water 24/7 then that water could be heated electrically or fan cooled or refrigerated as a low corrosion media.

[WSM]

I do fear that in the end you might need to devise some kind of temperature control setup to keep the system balanced in the intended setpoint. The composition is going to change, the boiling point is going to change, the current is going to change and probably a myriad of other factors that I can not fathom. So this may very well be a rather complicated task to keep the the cell at the right temp range during the whole run just using fixed settings.

One approach I can see is to run the cell a bit overdriven and use a fan driven air cooling system set to 110C. Simple on off temp controller and sensor in/on the cell should suffice to aid with keeping the temperature in check. Air cooling can be quite effective and does not usually cause thermal shock that could damage the precious glass vessel. Also it is a good safeguard against mishaps as the conversion approaches final stages....I would not sleep very well knowing that a large potful of electrolyte is bubbling away hanging at setpoint just by a thread and good will

 

 

I need to do a trial run and see how the system operates on its own. I have PID temperature controllers that use PTFE encased sensors, but I'll try the cell without that type of controller first.

 

If it runs okay without a controller, great! If not, then I'll use the controller. Either way, my goal is to run the system at 110^oC to optimize the operation with the least use of external controls, effort and energy expenditure.

 

I plan to modify my setup as needed, though. On that thought, the PID temperature controller is an "intelligent" system that reaches the programmed pre-set temperature and maintains it by controlling the input voltage. As long as the voltage in doesn't go below the minimum safe voltage for the cell and power supply, everything should operate without any negative issues.

 

WSM

[WSM]

It's very possible to support a reaction vessel in a large tank of water 24/7 then that water could be heated electrically or fan cooled or refrigerated as a low corrosion media.

 

If the high temperature sodium chlorate cell is run in a water bath, it'll never reach a temperature over 100^oC, which would frustrate the purpose of the experiment.

 

Also, I'm trying to minimize the use of external heating and cooling. Remember, I'm using the unpowered heating mantle as a convenient support, not a heat source.

 

Interesting thoughts, though. I think they'd be more useful in other applications.

 

WSM

Edited October 5, 2020 by WSM

[Andead]

Sorry took so long currently im very busy with my education. Chemistry and Biology are quite time consuming. I added some HCl to a water solution and then added the cathodes the white stuff, which i presume is TiCl2 came off very quickly. I have yet to test the electrodes again as my power supply failed probably due to corrosion from the HCl gas formed. Thanks for the help

[WSM]

Sorry took so long currently im very busy with my education. Chemistry and Biology are quite time consuming. I added some HCl to a water solution and then added the cathodes the white stuff, which i presume is TiCl2 came off very quickly. I have yet to test the electrodes again as my power supply failed probably due to corrosion from the HCl gas formed. Thanks for the help

 

 

It's always good to isolate the electronics from moisture and corrosives. Longer and larger gage leads may help (they work for me).

 

WSM

[royster]

If anybody is only looking to make single grams heres a miniature usb hypochlorite generator chlorate cell. 😀

[Arthur]

The USB hypochlorite electrodes as from China should make chlorate given enough time and temperature. However most folk here want to make more than their 1amp current rating suggests. But at current China prices they are a good start, just harvest product after a month of 24/7.