Hypothetical, alternative method to chlorate manufacture..

[Wedge]

Hello people, [especially the (g)Mods http://theforum.virtualave.net/ubb/smilies/biggrin.gif]

Is it possible to bubble ozone through a solution of NaCl or KCl to obtain NaClO3/KClO3?

[Lagen]

Even if it was possible (I doubt it is):
Ozone is extremely poisonous in higher doses. It will attack plastic, all kinds of cements and fittings in your reactor. Do you have a bottle of liquefied O3? If not, are you sure your ozone source capacity is sufficient to produce a visible amount of chlorate? A mole of gas occupies a volume of ca 22 liters. A mole => a few tens of grams of product at 100% efficiency. Now you should consider what is the concentration of ozone in the gas you would be bubbling through the solution? And how many years will it take to produce a kilo of product?

[Wedge]

Thanks Lagen, I appreciate your informative reply http://theforum.virtualave.net/ubb/smilies/smile.gif.

[deezs]

Hey Lagen!
Do you know this reaction?
2 ClO2 + 2 KOH = KClO2 + KClO3 + H2O
KClO2 is a good oxidizer too, so you don't need to separate it. The only problem with this, that you can make ClO2 from KClO3....
Oh, and It explodes ove 60 deg celsius. Need more?

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"Don't belive anything, just because there is a good proverb for it."

"To avoid injury in a battle, watch them from the nearer hill."

[FadeToBlackened]

Chlorates were once prepared by bubbling Cl2 through a hot solution of NaOH. This formed hypochlorite which then decomposed to NaCl and NaClO3.

[Lagen]

Hm, let's make some rough calculations...

Assuming that the reaction KCl+O3->KClO3 is true and happens with 100% efficiency of conversion (and please all chemists here don't flame me, the poster of this thread stated this was hypothetical). Assuming you wished to make 1kg of KClO3 with this process.

The solubility of KClO3 @25°C is 8.613g/100g H2O, and of KCl much higher, meaning you could use as little as 11.61 l of water to hold the reactants. In order not to slow down the reaction, make it a 12-15 l bucket.

Assuming first that you would be using the type of ozone generator sold as air cleaner. The lethal dose of ozone is 50ppm for 30 minutes, most toxins induce some very heavy damage at sub-lethal doses (orders of magnitude lower) but say that you value the kilo of chlorate so much you could take the crippling damage resulting from breathing 25ppm of O3. Assuming the density of air is 1.162 g/l (at 25°C, 100kPa, 50% RH and 0.04% CO2). You would thus have 29.05 micrograms of O3 per litre in the air to bubble through the solution. You need 391.66474g O3, i.e. 13482435.1 liters of the gas (again: over 13 million). Now by the time you would have bubbled your first million of liters through the bucket (I seriously doubt you could make it within the 30min limit, even if you were at good terms with your ozone generator - remember the bubbles must be small, they must be 100% reacted) - by that time you would be several times dead. Say you were able to react 10ml of the bubbles per second. You'd need 42 years and 9 months. For those 42 years you would have to keep replacing the destroyed reactor parts, broken ozone generators etc. so some contact with the gas would be unavoidable. Your total working time must not exceed 30 minutes, or 42 seconds per year. Of course... you could handle the mixture upwind, wear some ozoneproof spacesuit etc. But still, would you risk the metheorologists discovering some "ozone patch" in the area, and doing some research into it? http://theforum.virtualave.net/ubb/smilies/smile.gif

There are ozone generators that could do the job. You could use the ones sold for water treatment. They range approximately from $500 (you can expect a few hundred milligrams O3 per hour) to over $30000 (several hundred grams per hour & concentrations around 80000 ppm).

All in all, I think making a kilo of chlorate in this fashion is a bit inconvenient. I say stick to the chlorate cell, maybe make a big tank for it with an effective cooling system and use a couple welders to power it... This would be far cheaper than the above process and you would get your product within hours, or even minutes...

FadeToBlackened: Yes, and that's something completely different than the ozone reaction in terms of efficiency. The chlorine can be prepared by direct action of the current on the electrolyte, and the current efficiency is on the order of tens of percent. The chlorine can be made concentrated, and is stable.

Deezs: I suspect that is one of the reactions that happen in the chlorine process, will have a look at it.

[This message has been edited by Lagen (edited August 03, 2001).]

[deezs]

I made my few grams of KClO3 (for analytical use) with bubbling Cl2 through hot KOH solution. It has a bad yield, it is expensive and needs too much work.

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"Don't belive anything, just because there is a good proverb for it."

"To avoid injury in a battle, watch them from the nearer hill."

[BoB-]

A 1 gallon milk jug, a couple of batterys or a DC converter, and the electrolyte = cheap effective cell. (complete cell materials can be found at http://huizen.dds.nl/~wfvisser/EN/kclox_EN.html )

A couple of vent holes in the jug, and operating the cell in a bucket of ice are good ideas, keep in mind however that cell operation generates poisonous, flammable gas's.

An explosion is always a possibility.

Sacrificing a few Pyrex pans for the hypochlorite reaction (see the link above in my post) is much easier to get to work, but you tend to inhale more bad gas's with this way.

[FadeToBlackened]

Bucket of ice? I thought chlorate production was only favored at higher temps (50-80C)?

[Lagen]

You don't need cooling if you run the cell at moderate currents (tens of Amps at most). I mentioned a big tank with an "effective cooling system" because of the hundreds of Amps from the welders. IMO that's the thing to spend the extra bucks on if you want to scale up your chlorate production, rather than the BIG ozone generator, which could have about the same output. But still, designing a cell with a welder is not easy, usually the voltage is too low and some boiling in between the electrodes cannot be avoided. A good, stable DC output welder with voltage high enough to counter the huge voltage drops is expensive.

[This message has been edited by Lagen (edited August 05, 2001).]