Another method of KClO3 preparation

[frogfot]

Made potassium chlorate by passing chlorine through boiling potassium cabronate solution. This method is mainly for fun.

In original description (old chem book) they didn't mention how one should pass chlorine into solution, so I passed it through 5 mm glass tube which was tapped in short while.. cork in chlorine washer flyed out (luckily i did this outside). I lost some chlorine.. then I replaced glass pipe with an up-side-down turned funnel, this gave nice results, no tapping :D

The theoretical yield is slightly less than 15 g, i got 10 g. This is quite good since I lost some chlorine and some of chlorate was lost while recrystollising (2 times). To my surprise there was no chlorine escaping solution! ..well, smell appeared in the end of reaction.

This was my first time making so much chlorine, was literally shaking in the beginning for some reason :rolleyes: I used rubber gasoline pipes which showed to be good, no deterioration was noticed on walls :) (apparatus was left standing filled with chlorine for about 3 h)

Described the method here:
www.geocities.com/frogfot/synthesis.html#chloratedisprop

Also, same page got a pic of my improvised pressure equalising funnel (under "chlorine").

[kingspaz]

frogfot, thats a really good method by the sounds of it. a chemical process to prepare it is good because it can be done in bulk quantities.

[frogfot]

Mass production would be possible, but chlorine is expencive to produce (at least for me.. KMnO4). 50 g K2CO3 to 15 g KClO3 may not be profiteable but it's sure faster than electrolysis and one get lots of KCl (45g). One good thing is high purity of the product (no Na or other things like in electrolysis)

[Arthis]

Wouldn't it be possible to produce chlorine from table salt (NaCl) ? I think electrolysis could do that. As chlorine is a gas, there wouldn't be purity problems, and that would be extremly cheap.
HCl too, maybe ? I need to search a little.

Maybe chlorine for pools could be used too.

[a_bab]

Frogfot, in order to get chlorine cheaper, try alternative methods for oxydising HCl, like MgO2 (from batteries, use it as it is without purification). Another method which worked great for me (by accident of couse) is to mix 50:50 in volumes HCl and H2O2 (30%) and add Al foil. It rocks, you'll see ! You dont need to heat the mix, it'll reacting as soon as you'll add the foil. Experiment first in small batches of course.

Oh, these old chems books are really fun to read...

Arthis, producing Cl2 out of NaCL by the means of electrolysis is possible of course. The problem is that the amout of chlorine obtained in a given time is too small unless using huge vessels/industrial quantities of electricity.

[frogfot]

Duh!! I didn't even thoat about electrolysis, haha. a_bab, youre right that it will be slow, but assembling one on 15A will give about 20g/h thats nearly same speed I added Cl2 in my experiment. Another problem is equalising the pressure (in anode and cathode chambers)

Am I thinking right about following?
Both electrolytical and abovenamed method of chlorate preparation requires 3Cl2 to produce 1KClO3, however, first method gives 60-70% efficiency while second gives 100%. So, is second way more effective, or is there some catch?

[a_bab]

I would stick to the first method as is cleaner. The second method requires lots of heat, chlorine production on site (a tank would make wonders, more setup).
The first one is slow. The second is faster and the product is pure.

Well, if you have the resources, both methods are good. I'd choose the second one if I would be able to get a tank of chlorine.

[jeffchem2000]

if you add an acid to bleach chlorine gas is generated. I did this by mistake but luckily for me it was extra thick bleach so the chlorine took a long time to reach the surface. (enough time to get it outside) also if you add ammonium hydroxide to bleach chlorine is given off. but with different amounts of ammonia can lead to NCl3 being produced and in different conditions hydrazine. so this way isn't advisable.

[Skean Dhu]

why go through all of that trouble when you could make it mcuh simpler via the method found in NBK2000's PDF? (which i hope he dosen't mind me posting)
1200g HTH(Calcium hypochlorite 65% sold as a pool chlorinator) + 220gKCL mix with boiling water and let the Calcium chloride precip. out then filter while boiling hot and let the KCLO3 precip. out.?

[0EZ0]

I think you will find it rather difficult to crystallise CaCl2 out of solution as it is very soluble in water (75gm per 100ml Water). Destruction of hypochlorite to yield chlorate is tedious and usually gives a very poor yield. I'd prefer a chemical method myself to electrolysis, but I would not choose the hypochlorite method due to the amount of work needed and small yield.

The idea frogfot put forward was to show another way of producing chlorate relatively quickly with good results. In the coming weeks I may try this myself out of curiosity. Sounds like a good way to use that excess chlorine that escapes from a chlorate cell.

Nice work frogfot :cool:

[frogfot]

Wouldn't there be too small ammount of chlorine from chlorate cell? My cell (68W/2,6l) gave off <7g chlorine per 24 h (calculated from added HCl). So alot time would be needed. Though one good thing is that K2CO3 solution probably wouldn't have to be heated since such low conc of chlorine would react at room temp, or?

Would be nice to carry out the reaction till the end, it's interesting how much chlorine will escape at the end. (don't wanna upset neighbours, and this would be too much equipement to take to the forest..)

[0EZ0]

Yes thats quite true frogfot. The amount of chlorine liberated from a chlorate cell would be rather small and probably not worth it small scale. It may well be a nice way to prepare a side sample with high purity and no need for laborious task of removing graphite/carbon impurities though.

Another idea to explore may be to use Na2CO3 instead of K2CO3. Although I have seen no reference to using Na carbonate instead. Solubility between Na and K chlorates is supposed to be considerable, which may negate the use for a funnel to feed the chlorine into the scrubbing solution. Once the reaction is complete, convert to KClO3.

There are a few chemical methods of producing chlorine, some more attractive than others. The main issue is the rate at which the reactions liberate Cl2 and in what quantity. Too much at the wrong time may lead to gassing the surroundings with noxious chlorine. An alternative to producing chlorine chemically would be to use a chlorine/hydrogen cell with a membrane separating the anode and cathode. This solves the flow rate, and maintaining the cell to produce Cl2 would be a whole lot easier.

A few chemical reactions to produce chlorine below:

2 HCl(aq) + NaOCl(aq) ----> Cl2(g) + NaCl(aq) + H2O(l)

MnO2(s) + 4 HCl(aq) ----> Cl2(g) + MnCl2(aq) + 2 H2O(l)

2 KMnO4(s) + 16 HCl(aq) ----> 2 MnCl2(aq) + 2 KCl(aq) + 8 H2O(l) + 5 Cl2(g)

[frogfot]

With Na2CO3, formed NaCl would still tap the tube. Reaction also have to be driven to the very end, since it would be impossible to remove Na2CO3 by recrystallisation.

I was thinking about making a chlorine cell, but corrosion of graphite electrode annoys me.. Hopefully electrodes will last long with efficient cooling. I also found some info in a book on asbestoes membranes, hopefully, usual glass-wool will do as membrane.

[Mendeleev]

Can potassium chlorate be subsituted for potassium nitrate in black powder, I don't want to waste and potassium nitrate which I use to make nitric acid. Will potassium chlorate affect the power of my black powder?

[Bert]

If you directly substitute chlorate for nitrate in a black powder mix, it will be considerably more powerful and have a much greater pressure exponent. The net result, it will be dangerous to use in black powder arms. Rockets made with it will blow up unless you greatly enlarge the nozzle or add phlegmatizers such as oil or excess charcoal to the mix. Such mixes find use in salutes and for bursting small fireworks star shells. They are dangerously friction and shock sensitive, and may be cap sensitive high explosives depending on the ratios. The French government tried to substitute chlorate in military gunpowder very briefly at the end of the 18th century- in 1788, the pilot powder plant blew up, killing several people and the attempt was abandoned. The mix involved was 6 parts chlorate, 1 part Sulfur and 1 part charcoal.

[metafractal]

Substituting chlorate for nitrate in black powder is silly. Even if you do the stichometry and change the ratios, suphur and chlorates do not get along. The mix will be shock sensitive and prone to spontaneous ignition.
There is no real substitute for black powder using chlorates. H3, however, can be made with charcoal and chlorate. It behaves differently to blackpowder- markedly, its more energetic, but it is still insensitive and nice to work with. It can still be used in rockets like BP with some modifications. Some popular ratios are 10:3, 75/25, and 77/23 with about 2% binder. Many sources suggest hemp coal should be used.

[Mendeleev]

This H3 is intriguiging... I will have to try it very soon. As far as the chlorate sulfur mix, I think I will try that anyway ;), in very small quantities, no more than a gram. It is useful in blasting caps I hear, perhaps mixed with something else such as MF. Thanks for the info, twas' indeed helpful.

[0EZ0]

I would be careful with any composition involving chlorates. They tend to be rather sensitive to mechanical provocation. I'm sure one of our members (Arkangel wasn't it?) had an accident while pressing a chlorate composition similar to H3 into a rocket tube.

Chlorate & Sulfur is one of the priming compositions of old. To my knowledge it was NEVER used in commercial blasting caps. The mix is so sensitive that it can ignite if you try to mix the components in a mortar and pestle (even gently). If that sensitivity is not scary enough, spontaneous combustion can ensue with contaminated sulfur (with H2SO4) thanks to formed HClO3 which is dangerously reactive and explosive. What you were referring to was probably it's use in impact ignition primers used in old firearms. Since then there have been MUCH better, safer alternative priming compositions.

[Bert]

Chlorate and antimony sulphide, with various other goodies added were the basis of the old corrosive primers. Corrosive because of the KCl produced. Chlorate and sugar was what got Arkangel, as I recall. According to Shimizu, more friction/impact sensitive than chlorate/charcoal. H3 isn't very impact sensitive by itself, I've hit it on a clean anvil with a steel hammer and been unable to make it go off. When in contact with stars primed with Sulfur containing BP, it's another story! I've used H3 burst, but now I tend to use perchlorate based whistle mix with BP coated hulls for small ball shells (less than 6"). Just slightly safer in my estimation.

[Unburied]

Chlorine gas was once produced industrially by treating table salt with strong sulphric acid. Dont do it in the kitchen.
Draw the chlorine gas through a 20% NaOH solution to produce Chlorine bleach (NaOCl). You may need to provide cooling; when the NaOH saturates, oxygen will flash out of solution and foam it over.
Sodium Chlorate can be synthesised by carefully adding HCl to Chlorine bleach (try for a pH of 7) and gently heating (60 deg. C). The reaction is rather slow but its cheaper than electrolysis. The colour of the solution should go from that sick-piss yellow to clear.

[blindreeper]

Sorry to bust the bubble but you can't make Cl2 from NaCl and sulfuric acid. The reaction goes like this:

2 NaCl + H2SO4 -> 2 HCl (g) + Na2SO4

I have tried this myself so you can't say I am wrong :PI don't suggest you try it because hydrogen chloride screws over most metals in the vacinity. Most of the metal stuff in a 2 M radius of my lab is corroded :D

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