Sciencemadness Discussion Board - 3 NaClO → 2 NaCl + NaClO3 > KCl + NaClO3 → NaCl + KClO3

3 NaClO → 2 NaCl + NaClO3 > KCl + NaClO3 → NaCl + KClO3

Pyro_cat - 6-1-2020 at 20:13

Boiling bleach disproportionates sodium hypochlorite into sodium chloride and sodium chlorate...

They say the boiling is required for this reaction to work; you can't simply let the bleach evaporate.

Question is how much boiling time does it take for this disproportion to take place ?

I would rather just boil for a few minutes in the microwave (I can bring the microwave outside) if that's all it takes then set the solution aside to evaporate and do the next step in a few days.

I like this website https://www.thoughtco.com/potassium-chlorate-bleach-and-salt...

Microtek - 6-1-2020 at 23:30

The disproportionation happens faster at higher temperatures, it is not the process of boiling it, but the elevated temperatures that are necessary. You need to keep it at high temp for long enough that the reaction has time to "complete", but I don't know how long would be a good choice. I would guess that 30 minutes is ok, but longer will evaporate some of the water, so your yield will be higher when you add the potassium salt.

Pyro_cat - 7-1-2020 at 12:26

I am going to skip the microwave and use the side burner on the BBQ. If the wind ever quits.

But faster at higher temperatures, very interesting because at "a pressure of 1 bar or approximately 100 kPa (15 psi) above atmospheric pressure, water will reach a temperature of 121 °C (250 °F).

Maybe that would increase yield past whats obtained from boiling at what ever temp bleach normally boils.

Might have to explore that.

symboom - 7-1-2020 at 13:40

A test would be if the solution reacts with hydrogen peroxide given there is no transition metal contaminates so if oxygen forms bleach is still not fully converted

Microtek - 7-1-2020 at 23:42

As a rule of thumb, a 10 degree (kelvin) rise in temperature will double the reaction rate, so 120C should be about 4 times the rate at boiling. Note that it won't affect the yield directly, just the time it takes to get to completion. The advantage of boiling is that by reducing the volume of the solution, less product will be dissolved in it rather than filtered off as crystals, so your yield will be higher.

Pyro_cat - 6-3-2020 at 18:52

I finally did this project.

I used a $17 3 quart slow cooker and simmered the bleach for a day for then took the lid off and it took about 10 hours to evaporate down to where I saw the sodium chloride collecting on the bottom and a crust on the top. Stirring the stuff on top seemed to redissolve the top crust into the liquid. Did that a few times over the next hour till it seemed it just sank to the bottom.

With the lid off the evaporation drops temperature quite a bit. The heating element doesn't produce enough heat to boil it with the lid off.

Filtering. The remaining liquid kept dissolving the coffee filter and it would break then I doubled them up and got it filtered.

I didn't measure it was about 500 ml of liquid. Then I heated an equal amount of water and dissolved the potassium chloride salt substitute, filtered , reheated and added it to the first solution and right away I saw some precipitation starting. Then ice bath cooling and it began collecting on the bottom.

Used about 68 grams of potassium chloride as I measured 20 left from an 88 g container.

And just measured 60 grams of final product minus 1 or 2 I used for tests.

Was very sloppy with measuring and recording, I just wanted to see if this would work and it does.

Pyro_cat - 6-3-2020 at 19:05

Quote: Originally posted by symboom

A test would be if the solution reacts with hydrogen peroxide given there is no transition metal contaminates so if oxygen forms bleach is still not fully converted

I am getting some peroxide before the next batch.

Even though your never supposed to smell chemistry projects it didn't smell much like bleach after the simmering but like I wrote above it did seem to dissolve the coffee filter suspended by the edges and cause it to break by the weight of the liquid. Maybe that was un reacted bleach causing that.

Pyro_cat - 10-3-2020 at 21:24

This time simmered it for a whole day then another day evaporating with the cover off till the crystals formed and when filtering the single filter did not get eaten and rip in the process.

This time I am cooling the filtrate and something is precipitating out. I think its sodium chloride maybe some sodium clorate too I don't know but I am going to filter that stuff out and then when I get more potassium chloride for the next step see what happens.

And peroxide for that test too.

I need to order a microscope. Probably learn a lot looking at all these crystal things with a microscope. I know regular salt is all cubes.

[Edited on 11-3-2020 by Pyro_cat]

Pyro_cat - 5-4-2021 at 16:58

I never ordered the microscope. But I am going to.

Think I am on my 6th batch now, the hypochlorite for swimming pools works better then bleach but there is this brown yuck that makes it through the filter.

Its interesting the slow gravity filtering the potassium chloride it floats on top of the boiled bleach and makes this disk of chlorate between the layers then you shake it and starts to precipitate even before the freezer.

Its also interesting watching the NaCl crystals form a top layer as soon as you take the top off the crock pot once the bleach disproportionates.

Are all those crystals NaCl or are some sodium chlorate if you boiled it down to far? and yield loss.

I am going to have to dry that whole mess out mix some with sugar and see what happens. See of it burns.

What I also noticed on this last batch is I was adding the potassium chloride to a soda bottle full of hot water and it cooled it.

For a second I thought I should have used hotter water but I did use hot water and it felt not chilled but colder then ambient so it must be doing that instant cold pack endothermic thing.

[Edited on 6-4-2021 by Pyro_cat]

Pyro_cat - 6-4-2021 at 11:17

Drying out the Kclo3 and its alot like the getting the water out of Epson's salt (magnesium sulfate heptahydrate) experiment. Its like that same slush that just refuses to dry out.

caterpillar - 7-4-2021 at 14:41

I think it would be better to start with Ca(ClO)2. At least, this compound can be obtained in the free market.

Pyro_cat - 14-4-2021 at 19:03

Quote: Originally posted by caterpillar

I think it would be better to start with Ca(ClO)2. At least, this compound can be obtained in the free market.

I saw it in the pool section "73% Calcium Hypochlorite"

Online I just read another brand "68% Calcium Hypochlorite, which means 67.4% free chlorine"

Means the rest is calcium and oxygen or some filler junk for more bulk?

MSDS time

All that NaCl but Ill try it.

KCLcoal - 17-4-2021 at 02:23

Quote: Originally posted by Pyro_cat

Boiling bleach disproportionates sodium hypochlorite into sodium chloride and sodium chlorate...

They say the boiling is required for this reaction to work; you can't simply let the bleach evaporate.

Question is how much boiling time does it take for this disproportion to take place ?

I would rather just boil for a few minutes in the microwave (I can bring the microwave outside) if that's all it takes then set the solution aside to evaporate and do the next step in a few days.

I like this website https://www.thoughtco.com/potassium-chlorate-bleach-and-salt...

Sodium hypochlorite decomposes into sodium chloride and oxygen molecules when boiled (100 ° C). On the other hand, when heated at a temperature of 80 ° C for a long time, a disproportionation reaction that produces chlorate ions mainly occurs.
For amateurs, the boiling method is recommended for the production of chlorate as a method of removing the unstable salt hypochlorite ion from the chlorate. (Boil time about 10 minutes)
For your purposes, boiling will cause only some disproportionation reactions and most of the hypochlorite ions will only decompose.

On the other hand, at a temperature of about 80 ° C, the target disproportionation reaction becomes the mainstream, and the decomposition reaction into sodium chloride and oxygen molecules can be suppressed. However, it requires long-term heating.

Boffis - 17-4-2021 at 10:03

Does anyone have a paper that gives a clue as to the rate of disproportionation at different temperatures and at different concentrations of excess NaOH?

Pyro_cat - 17-4-2021 at 15:20

Quote: Originally posted by KCLcoal

On the other hand, at a temperature of about 80 ° C, the target disproportionation reaction becomes the mainstream, and the decomposition reaction into sodium chloride and oxygen molecules can be suppressed. However, it requires long-term heating.

Thanks

I don't have any bleach so I just put water in the crock pot and set it to low see what temp it gets to. A crock pot is ideal for long term heating, done several batches in it and the ceramic is not effected at all.

I will check the temp in a few hours. Its a little windy so it will be lower then when its still out. On high with any breeze it would not boil unless covered with a towel.

Could also use the variac to get that target temp on high setting too.

Pyro_cat - 17-4-2021 at 18:51

Its at 77C on the low setting. Nice.

BauArf56 - 18-4-2021 at 07:42

bubbling chlorine through an hot sodium hydroxide solution produces sodium chloride and chlorate, which can be displaced with a potassium salt to give insoluble potassium chlorate. This method is not very efficient, as it produces lots of chloride and hot naoh is too corrosive. This was just an idea

Laboratory of Liptakov - 1-5-2021 at 06:50

I have not yet seen a reliable and well-described method Cl2 + NaOH = NaClO3. Or Cl2 + KOH..... :cool:

caterpillar - 1-5-2021 at 13:17

Quote: Originally posted by Laboratory of Liptakov

I have not yet seen a reliable and well-described method Cl2 + NaOH = NaClO3. Or Cl2 + KOH..... :cool:

I did. Bubble chlorine gas through a boiling solution of K2CO3. So simple. One detail- the tube (its part in liquid) must be wide enough otherwise it will be blocked with crystals of KClO3. I made such an experiment. The only thing to be kept in mind is to complete the process- to transform all carbonate.

Laboratory of Liptakov - 1-5-2021 at 23:12

So easy? Interesting.....Equation say : K2CO3 10g + Cl2 5,1g = 3,2g CO2 + 9g KCl + 3g KClO3. Advantige is, that KCl is 88x more soluble in water than KClO3.

Solubility.....KCl......277,70g in...100g H2O at 0 C
Solubility.....KClO3.....3,13g in...100g H2O at 0 C

Now we obtain 3x more KCl than KClO3. But KCl stay in solution and KClO3 will crystalised. Maybe with pretty good purity. Cl2 is easy produce from pool tablete. Interesting methode.
And because KCl + CO2 during reaction again create K2CO3 which again reacting with Cl2.....all process may ended with pretty pure KClO3. Without KCl in solution.
Thanks.... :cool:

...Very interestling

[Edited on 2-5-2021 by Laboratory of Liptakov]

caterpillar - 2-5-2021 at 03:46

Quote: Originally posted by Laboratory of Liptakov

Now we obtain 3x more KCl than KClO3. But KCl stay in solution and KClO3 will crystalised. Maybe with pretty good purity. Cl2 is easy produce from pool tablete. Interesting methode.
And because KCl + CO2 during reaction again create K2CO3 which again reacting with Cl2.....
[Edited on 2-5-2021 by Laboratory of Liptakov]

Do not disappoint me, mate. HCl is a much, much stronger acid than H2CO3. KCl won't react with CO2 (nor H2CO3). The only advantage of this method is that you'll have no need for KOH.

Alkoholvergiftung - 2-5-2021 at 07:26

I dont think this reaction works with Alkali carbonats. In the Book "Bleichchemikalien" they wrote. That if Soda is used it forms only hypochloric acid.
Na2CO3+2Cl+H2O = NaCl+ NaHCO3 + HOCL
If you add more chlorine the reaction is
NaHCO3 + 2Cl = NaCl + CO2 +HOCl
I think the reaction is the same for Potash.

metalresearcher - 2-5-2021 at 09:29

Never heard about electrolysis ? This releases ClO- which will be oxidized to ClO3- when the solution is above 60 C. No toxic Cl2 or bleach needed,

caterpillar - 2-5-2021 at 11:07

Quote: Originally posted by Alkoholvergiftung

I dont think this reaction works with Alkali carbonats. In the Book "Bleichchemikalien" they wrote. That if Soda is used it forms only hypochloric acid.
Na2CO3+2Cl+H2O = NaCl+ NaHCO3 + HOCL
If you add more chlorine the reaction is
NaHCO3 + 2Cl = NaCl + CO2 +HOCl
I think the reaction is the same for Potash.

I think nothing on the issue. I know. I read it in one of the books on the inorganic synthesis and I have its text (no English). And I made this preparation myself. The solution must be hot (must boil) and the reaction goes just as I described.

Laboratory of Liptakov - 3-5-2021 at 05:15

Interesting, that solution must boil. Maybe is it a key for successful. Reagents are easily available and process is relatively easy. Therefore is it interesting. Against electro cell method.... :cool:

caterpillar - 3-5-2021 at 14:04

Quote: Originally posted by Laboratory of Liptakov

Interesting, that solution must boil. Maybe is it a key for successful. Reagents are easily available and process is relatively easy. Therefore is it interesting. Against electro cell method.... :cool:

The disadvantage is that you have to prepare chlorine gas. The simplest way for me is to keep the solution of Ca(ClO)2 at, let's say, 80 Celsius for hours, then mix it with the solution of Na2CO3.

njl - 3-5-2021 at 16:23

How fast can you make the reaction with Cl2 gas? Cl2 might be trivial to make for most of us, but maintaining a chlorine generator for hours doesn't sound fun.

caterpillar - 3-5-2021 at 22:00

Quote: Originally posted by njl

How fast can you make the reaction with Cl2 gas? Cl2 might be trivial to make for most of us, but maintaining a chlorine generator for hours doesn't sound fun.

The reaction goes quickly. The check is very simple- can you feel the smell of chlorine near your vessel with the solution of K2CO3 or not. Wide tube, and put it down into the reaction vessel as deep as it is possible. However, I do not think that you'll be able to complete the whole process in ten minutes.

caterpillar - 4-5-2021 at 13:58

Quote: Originally posted by caterpillar

Quote: Originally posted by Laboratory of Liptakov

The disadvantage is that you have to prepare chlorine gas. The simplest way for me is to keep the solution of Ca(ClO)2 at, let's say, 80 Celsius for hours, then mix it with the solution of Na2CO3.

Or it would be better to filter water with CaCl2 +Ca(ClO3)2 and add the solution of KCl.