What Went Wrong in My Attempt to Make Potassium Chlorate?

[mrjeffy321]

I am trying to make some Potassium Chlorate (KClO3) by reacting bleach (NaOCl) with Potassium Chloride (KCl). I got this idea from this site:
http://www.fryingcolors.com/kclo3.html
I am trying to do the first method using the NaOCl and KCl.

I have followed the steps, kind of, and ended up with a dark browish percipitate. this is odd, since the reaction for this should yeild Potassium Chlorate, a white powder.

NaOCl (aq) + KCl (aq) --> NaCl (aq) + KClO3 (aq/s?)
add Potassium Chlorate to boiling/almost boiling bleach and get sodium chloride and Potassium Chlorate.

to save you some reading on the linked site, i'll tell you how it should be done, and then how I did it.

How it should be done:
-bring bleach to almost boiling (instructions say 1 gallon)
-add the Potassium Chlorate (instructions say 63 grams)
-continue to let it react until you get it to a specific gravity of around 1.3 (as measured by a hydrometer)
-let it cool, put in refrigerator and let the Potassium Chlorate crystalize
-filter out the crystals
-repeat steps again with remaining liquid to be sure everything reacted
-then add the stuff you get out of the filter to distilled water (instructions say 56 grams/100 mL water)
-boil new solution
-evaporate the water, and collect the Potassium Chlorate

How I did it:
before I started, I decided to work out this reaction on paper, and the theoretical amounts of each substance i needed, so i based my figures on that, but even if i don't get a compleate reaction, i should still get something
-bring bleach to almost boiling (I used just over 1 liter of 6% bleach)
-add the Potassium Chlorate (i don't know any more how much I used)
-continue to let it react until you get it to a specific gravity of around 1.3 (well I had a hydrometer, but I don't think it is very accurate, so i let it sit there for a long while, until I was pretty sure it had reacted all it was going to do, but the number [approx.] I was getting on my hydrometer was 1.15)
-let it cool, put in refrigerator and let the Potassium Chlorate crystalize
-filter out the crystals
-repeat steps again with remaining liquid to be sure everything reacted

I am currently at this step, I haven't gone this far yet

-then add the stuff you get out of the filter to distilled water (instructions say 56 grams/100 mL water)
-boil new solution
-evaporate the water, and collect the Potassium Chlorate

I don't know how much of a diference these last 3 steps will make, but I doubt that they will take my dark brown stuff and make it into good 'ol Potassium Chlorate, (unless I am wrong, i don't know)
also, the vapor that is coming off this liquid solution while boiling and going out the exhaust suction, some of it is condensing around the grill plate and it is becomming a whitish powder, but then when I go to wipe it up, it looks much more yellowish on the paper towl I use, what is this stuff, in theory the only thing to evaporate in this reaction is water which last time I checked won't leave a residue behind.


I just though that maybe someone here could offer me insight into what is happening and, what should be happening.


just so you guys arent worried (to much) about my safety while doing this [this seems to always come up when I do something dangerous (thermite)] I will tell you that I know what Potassium Chlorate is capeable of, and I am doing the boiling with a ventalted exhaust near by, I won't be eating any of this either.

 

[chem_tr]

Hello, I will only discuss the redox chemistry of the reaction, maybe the reaction needs reviewing.

Cl⁺ + 2e^- ---> Cl^-
Cl^- ---> Cl⁵⁺ + 6e^-
------------------
3ClO^- + Cl^- ---> 3Cl^- + ClO₃^-

We may even simplify it by subtracting the chlorine on the left:
3ClO^- ---> 2Cl^- + ClO₃^-

So, you should check the concentration of bleach; as you see in the redox reaction, three moles of bleach is needed to produce one mole of chlorate. Also, brown precipitates don't seem normal, please check the purity of your substances. Use distilled water as much as possible. If there are particles in your starting solutions, don't let them interfere with your business, just filter them off.

I haven't checked your concentrations, since we use SI units in Turkey, I am not familiar with gallons, etc.

Regards,
chem_tr

 

[thunderfvck]

http://www.wfvisser.dds.nl/EN/chlorate_EN.html#therm_starting

Check out that link and try using his procedure instead.

I'm inebriated at the moment so I'm unable to see why your procedure is wrong.

But assume that the link I provided will give you a procedure that WILL work (the guy who made the site is highly respected).

 

[Azrioch]

I'm inebriated at the moment so I'm unable to see why your procedure is wrong.

haha

 

[Gokul43201]

We really can't say much about the quantitative aspects for 2 reasons :

1. We don't know how much you've used (we could tell you how much to use, but it seems you've already figured this out)

2. Like you said, the problem seems to be not about how much, but rather about , "what the #$%^ is this brown/yellow stuff and where did it come from ?"

Okay, here's my five cents :

1. Do you buy KCl from a Chemical Supply or do you use some kind of Lo-salt ? If you buy from a chemical supplier, they might just sell you KClO3. If you use LoSalt, you might want to check on the other components. Most LoSalt is only about 70% KCl, so there's lots of other stuff.

2. There may be impurities from water or bleach. Why don't you use sodium chlorate (weed killer) instead of bleach ? I'm sure that's the more common approach.

3. Have you tried a basic flame test on your brown precipitate and your yellow condensate ? If you see colors other than lilac, that's a strong indication of impurity. Incidentally, potassium hypochlorite is a pale-yellow salt. Often, a little salt can be carried away by the steam ...depending on the size of the crystallites/particles - especially with vigorous boiling.


{Hmmm...first the thermite, then potassium chlorate. The word that comes to mind - pyrotechnics. I hope it's nothing more sinister than that.}

 

[mrjeffy321]

Procedure when using sodium hypochlorite
It is assumed bleach will be used, which is usually a 4% solution of sodium hypochlorite in water. If a less or more concentrated solution is used, adjust the amounts accordingly.
1. Take 1 liter of bleach, and place this in heat resistant glass or stainless steel container. Bring it to a boil.
2. Boil the solution until only about 140 ml of solution is left. The exact volume is not critical, a deviation of 10 to 20 ml is acceptable.
3. Allow the solution to cool. If crystals form upon cooling, filter the solution after it has completely cooled. The crystals are sodium chloride and can be discarded.
4. In a separate container, prepare a solution of potassium chloride. Dissolve 28 grams of potassium chloride in the smallest volume of water possible (about 80 ml). This can be done by dissolving the potassium chloride in about 90 ml of boiling water, and allowing it to cool. If crystals form, add some more water, boil again to dissolve the potassium chloride, and allow to cool again. If crystals form, repeat. If not, the solution is ready to use.
5. Mix the boiled bleach solution with the potassium chloride solution. A white precipitate should form. This is potassium chlorate.
6. Bring the solution to a boil and add water until all potassium chlorate has dissolved.
7. Allow the solution to cool slowly. Crystals of potassium chlorate will form. Cool the solution to 0 deg C.
8. Filter to obtain the raw potassium chlorate. Rinse the crystals in the filter with ice-cold water. The product can be further purified as described below.

this procedure seems very similar to what I was doing, althugh the above procedure seems to need very concentrated solutions of both bleach and potassium chlorate, something that I am probably not getting close enough to.

I am getting my potassium chlorate from a salt substitute (walmart), but this isn't one of those reduced salt ones, this is suppose to be no sodium stuff.
and I am using bleach that starts out as 6% by weight.

I did try burning some of it, but I don't think anything happened, i just burned the remnents of it that I couldn't scrape off the filter, but i just think that the filter paper is what burned, not the brown stuff. I am now evaporating the water off the "cleaned" brown stuff, so once it is dry i will be done with all those steps, but I barely have anything to show for it.

 

[mrjeffy321]

actually, I think now I will try to do it the way that is in that link you gave me, with the high sconcentration solutions.

but I just can't figure out why I am getting some type of brown percipitate forming, could it be because I am not using a high enough concentration of something? or not getting it hot enough?
when I filter out the percipitate, I get (what looks like to me) a highly concentrated bleach solution, it smells like bleach and looks like bleach, just darker, and when I try to make more potassium chlorate using the same method with the "new" concentrated bleach, the same thing happens.

maybe I should incest in a good electronic hydrometer, not rely on the leaky, possibly broken, old battery hydrometer I had.

 

[mrjeffy321]

OK, last night I (tried) to make a very concentrated solution of Sodium hypochlorite, but I may have only partialy succeded.

I took about 1 liter of 6% chlorox bleach and boiled it until it was about at 200 mL, then as I was letting it cool, I added some tap water to try to redisolve some of this stuff that has come out of solution ( i don't know what exactly it is, possible sodium chloride?, or NaOCl that came out of solution?) then I let it cool some more. afterward I filtered the solution twice with a pair of coffee filters, an collected a lot of dark k and some other stuff that could be sodium chloride (since I think when you heat the bleach, some of it becomes sodium chloride). so I now have a solution of around 300 mL of what should be concentrated bleach. I will describe the solution:
a dark yellowish color (similar to dark urin, especially when it was still warm)
it smelled like bleach

I didnt add anything else to the solution while it was heating, just let the steam evaporate away. the vapor coming off theoretically should be steam, H2O(g).

but all this brown stuff that was made is concerning me, what is it and why is it there? it is just like the stuff that I had when I was trying to make potassium chlorate the other way. and while boiling the bleach, it got very dark in color, almost pure black, a very dark bown, but then went back to the dark yellow when it cooled, leaving some type of percipitate.

 

[mrjeffy321]

Success, kind of

I have tried 2 trials, and I am preparing the 3rd trial now, here are my results:
trial 1 - used only a 6% blech solution and not very much KCl, I only get brown stuff
trial 2 - used much more concentrated bleach solution with much more KCl, and here I did get some KClO3 crystals, not much, but some
I tested to see if it was KClO3 by adding sugar to it and burning it, I couldn't get it to burn very easily without the sugar, but the flames resulting sure arent any regular sugar flames I have ever seen, very bright, light blue flames, burns very quickly.

trial 3:havent done yet - I will use MUCH more concentrated solution of bleach, and a saturated solution of KCl, so in theory, this should work best.
I wonder if I will need to heat the solution(s) to get them to react, or will room temerature work just as well? I probably will get fater, more compleate reults if I heat it.


Is there a point of maximum saturatation for bleach (NaOCl)?, were even if I try to get it more concentrated, I cant, i'll just be waisting my time?

 

[mrjeffy321]

OK, I am not totally clear on how exactly I obtained this substance, my best guess would be from when I was making concentrated bleach and then filtered it to get the particles out, which I thought was sodium chloride but just for fun one night, I decided to test to see if it really was by trying to burn it with sugar like I did with the other stuff i had made, and to my surprize, IT WORKED. now I know this stuff just isn't sodium chloride anymore, and I think I got it from what was a relativly pure solution of what was bleach, I just filtered it out and dried it.
So now I have 2 substances, one I got in my "trial 2" described above using a more concentrated bleach solution and lots of potassium chloride and it burns with sugar to produce a white/light purple flame, so I would have to say that my first substance is potassium chlorate. my second substance I think I just got by heating up the bleach, getting it more and more concentrated and making more and more salt, then perhaps could the sodium chloride have reacted with the bleach and made sodium chlorate perhaps? my substance 2 burns with sugar to produce a much more yellowish flame.
(now remember these colors that are being described are my opinion of what color it is, which may be slightly flawed because I am color bind, but I other people who have witnessed my reactions describe the color similary)

I have looked up what color both sodium and potassium chlorate should burn like:

The most useful element in pyrotechnics that belongs in in the alkalies period is potassium. It is more common than lithium and does not produce a yellow flame like sodium. The strong sodium flame color easily washes out other and can contaminate other compositions to ruin them. The weak violet flame that potassium gives off is advantageous because it doesn't interfere with color production. It is rarely used by itself to produce purple, instead a mix of blue and red are used.

I have also video taped the 2 substances burning on my computer, it is kind of hard to tell colors though because of the brightness of the combustion, but someone might be interested in seeing it, but I can't attach it because my 1.2 Mb file it too large, so here is a link to it on a geocities page:
http://www.geocities.com/mrjeffy321/chlorates

 

[mrjeffy321]

well no one seems to be reading this, or at least responding, but I will keep posting my status, for a while anyway, it helps give me a chance to rethink some of this stuff while writting it,


When I was making my concentrated bleach solution, I boiled down over a liter and a half of bleach to around 400 mL, so it should be extreamly concentrated, in theory. well as it was boiling, it did as I expected, made that brown stuff, then I filtered it, then continued boiling and no more brown stuff was made. I am concluding that the brown stuff is the result of some type of reaction that is occurring in the 94% other in the bleach (6% sodium hypochlorite, 94% other, not all water I suppose).then once its gone, it is gone. then when it started getting lower, I started seeing large buildups of a white crust on top, and globs of a while powder at the bottom of the pan, ( assumed it was sodium chloride), so when I got done boiling it, I filtered out the "salt", then let it dry. later I decided, "hey, what the heck, i'll test the "salt" and try to burn it with sugar like I would do with the potassium chlorate, and to my surprize, it worked (like I told you all in an earlier post, I assume the "salt" is actualy sodium chlorate resulting from sodium chloride reacting with the sodium hypochlorate).
but now let's get back to the concentrated bleach solution, if you can call it that, since it exibits almost no bleach properties any more, it doesn whiten fabrics, it doesn't smell like bleach (it smells like something familiar, but I just can't place it), it doesn't react like bleach, as a matter of fact, the only 2 reasons I once though it was bleach are because it was made from bleach and it had a dark yellowish color. what I am thinking now is that while boiling, some/most of the bleach was reacted and made oxygen gas and sodium chloride, then intern, that sodium chloride reacted with the remaining bleach to form the sodium chlorate, but leaving the bleach color behind. if you haven't watched the videos I put up, I encourage you to, although it is hard to tell colors because of the brightness of the flame, you can (and me especialy since I was right there) see the color diference in the 2 combustions. I have also tried to make more potassium chlorate with that concentrated "bleach", but was unsucessfull even using highly concentrated solutions of potassium chloride.

 

[mrjeffy321]

I have now made some chloate (potassium I guess) using the calcium hypochlorite method. i found it to b less labor intensive than the bleach method, because I started out with my solutions at the correct concentrations already and I didnt have to boil down and destroy the stuff that I needed in the first place. but that method is harder, since I don't have a good supply of pool shock (calcium hypochlorite) and it seems to be more corosive on my pan that I used than the bleach was.


I think I will try to do the electrolysis method not, even though I will like that one the least, but technicaly it is the most efficient and less labor intensive of the three.

 

[Marijn]

Man, your persistant, that's for sure!

What are you going to use the stuff for?
fireworks? amateur rocket-engine?

 

[mrjeffy321]

actually, you just listed my two main things I want to do with it, general pyrotechnics fun and model rocket fuel.

Man, your persistant, that's for sure!

well, yes, but mainly no one is really responding anymore, I just use this a a place where I can recount my experiments, and by doing this I kind rethink them in my mind so I don't loose any details later if I forget, plus is anyone responds, that's good too! but that hasnt happened in a while, the last 7 posts were mine. and maybe later on, month or years from now, someone else can benifit from my experiences if they are trying to do what I am doing. if anyone would like to contribute, by all means, join in.

 

[mrjeffy321]

OK, this is actually a question, not just an update on what I am doing now:

using this page for a source of ways to make potassium chlorate,
http://www.wfvisser.dds.nl/EN/chlorate_EN.html#therm_starting
it disscusses an electrolytic method that uses sodium chloride as an electrolyte in water, and then runs a current though the water to turn the sodium chloride into sodium chlorate (from NaCl to NaClO3) because of a length series of reactions that are explained on the page.

my question is, could I not just take bleach (Sodium hypochlorite, NaOCl) and electrolysize that, since it is already in an aqueaus solution, therefore only needing to add 2 oxygen atoms to the compound, rather than the 3 atoms using the other method. (from NaOCl to NaClO3?)

I have found out that normal cloroz ultr bleach is composed of:
6.00% sodium hypochlorite (NaOCl)
5.63% Sodium chloride (NaCl)
0.015% caustic soda/sodium hydroxide (NaOH)

it seems like this reaction in question would be perfect to make sodium chlorate because it will require less time/energy to add only 2 oxygen atoms (rather than 3) and it contains sodium chloride as well for the old reaction, and the .015% sodium hydroxide won't last long anyway once everyting gets started.

will this work?

 

[mrjeffy321]

I would very much like to know if my idea from above would work, taking a shortcut by electrolysizing bleach insted of salt water.

I know bleach can be made by electrolysizing saltwater, but can't you just keep on going and make sodium chlorate too?

 

[mrjeffy321]

I have went ahead and electrolysized the bleach, and here is what happened:

I let it run for about 20 hours to get these results,
the solution has lost its distinctive bleach color, it is now much more clear after being filtered to remove the gunk produced as a result of the elctrolysis process. it isn't totally clear like water, but if you arent carefull, you can mistake it for water.
the smell, it has a chlorinated smell, similar, but somehow more chlorinated than bleach normally smells like (probably because of all that chlorine gas produced), but it isn't a stong a smell.
it has lost most of it's bleaching property on fabric, still will somewhat whiten fabric, probably because it isn't totally finished electrolysizing.

other than that, that is all to report for now, still wished I knew what I should be expecting fromt this.

I think when doing this, the pH should rise throughout the process, and the pH starts out at about 11.4 anywar, but in order for me to get effective results, I think I need someone around 6. but in bleach production through electrolysis, you want a high pH, is it possible I could be making MORE rather than less bleach? but this wouldn't be likely because of my results.

 

[mrjeffy321]

I have answered my own question about whether it will "save a step" by electrolysizing an aqueus solution of sodium hypochloite (NaOCl) insted of sodium chloride (NaCl) to make Sodium Chlorate (NaClO3).
the Answer: No, although i will end up making the same thing in the end, since oxygen is made while electrolysizing the sodium hypochlorite electrolyte (and let to escape from the system), it takes away precious energy that could be used somewhere else, but is insted lost. When electrolysizing the aqueus sodium chloride solution, very little to no oxygen is made, energy more or less goes into making the chorate. If you go and calculate the theoredical energy need for both methods, the sodium chloride method would need something like 6 fardays/mole of chlorate, and with the sodium hypochlorite method, it is something around 9 fardays / mole of chlorate.



I have disscussed this with a diferent, more knowlegible, chemistry teacher, and she is under the impress that I am doing the impossible, what I am trying to do (and the results I am getting) should not be happening, and I understands why she thinks this, because all the stuff I am using to make gthe chlorate and the chlorate itself is soluble in water (some of the substances more than others), but she thinks that everything will end up being dissolved and I won't get anything to precipitate out. and yet, experimentally, I know that I infact do, and the stuff that does percipiatate out, has properties very similar to that of the chlorates that I am trying to male (sodium and potassium chlorate).

 

[mrjeffy321]

like i said above, the chemistry teacher I talked to doesn't think that what I am getting is really chlorate, but rather some kind of hydroxide(thats what she says), but I think I am actually getting a chlorate based on the reactions that I can produce with the stuff I get and all the "people"/souces that I have with similar instructions on how to make it.

is there anything that I can do to prove/test what I am getting to see what it is, if it is a chlorate or not? I thought that flame test with sugar was pretty good proof, especially with the distinctive colors I saw, but is there anything else?

 

[chem_tr]

You may have obtained a peroxide, as it helped burning. You can try treating the solid you obtained with hypochlorite, and if it is chlorate, all of them might be converted to chloride, easily detected with silver nitrate.

 

[mrjeffy321]

You may have obtained a peroxide, as it helped burning.

a peroxide, I never thought of that, i suppose it may be possible, but I quickly looked up sodium and potassium peroxide (dont need to look up hydrogen peroxide for obvious reasons) and they are a pale yellow color and a yello/orange color respectively, not the while/off white that I am getting.

You can try treating the solid you obtained with hypochlorite, and if it is chlorate, all of them might be converted to chloride, easily detected with silver nitrate.

I know anything about that, isn't it all ready in contact with the [sodium] hypochlorite when it is being made, therefore if anything is going to happen, it would have already happened?

 

[mrjeffy321]

I was experimenting with the electrolytic production method, trying diferent voltages, currents, finding the built in resistance of my chlorate cell, and after just a few minutes of opperation, I get this white percipitate that accumulated near the bottom.
at first I thought that this stuff was perhaps copper chloride, since there was a little bit of copper wire exposed to the water between my power source and graphite electrodes, so I thought that the chlorine was reacting with the copper to make copper chloride, which is very very insoluble and thus settles to the bottom, and copper chloride is white, just like my percipitate.
then I covered up the copper that was exposed (to the best of my ability) so that only the graphite was the stuff conducting the electricity into the water, again, after just a few minutes, I get the white percipitate still.

So could this stuff be sodium chlorate, the stuff I am trying to make in the cell?
sodium chlorate is highly soluble (100g/100mL), and I do seem to making a lot of this percipiate in a shor period of time, but then again I am using a lot of current (it varried, but is mainly between 1.2 and 2.7 amps at somewhere between 4.5 to 7.5 volts), so that might explain the speed of production. and the sodium chlorate has to compete with the virtually totally saturated sodium chloride solution (36g/100mL), so maybe it is producing more sodium chlorate than it can redissolve in the amount of water that is being left "empy" from the usage of sodium chloride. the percipiate is hard to remove from the water, it is almost totally usless to use a coffee filter, it will just pass right though, the only way I can clean out the water is to decant the clear water off and let the stuff settle out.

what could this stuff be?

 

[mrjeffy321]

the more knowlegible of the two chemistry teachers which I ask about this stuff told me, very quickly and confidently after she learned that I was using tap and not distilled water, that that white fluffy percipitate was some of the impurities reacting in the water, and it just may be so, I tried electrolysizing the solution for an hour (as compared to only a few minuted as before) and got no noticible increase in the amount of percipitate, so it could be that I used up all the impurities and now it is just a pure sodium chloride/ate/hpochlorate.. (and all that other stuff that goes on in the cell) solution, or i just didnt look hard enoug at it.

 

[mrjeffy321]

OK, I did the electrolytic method for a while, I was going good and then some stuff happened (ie. I spilled the cup and weird stuff happened to the voltage and current that baffle me as to their cause, ...). anyway, I eventually deci9ded that I would continue on with the next step, which is taking the sodium chlorate I had just made and transforming it into potassium chlorate. I did the steps, ..., and anyway I filtered out the crystals I got, and tested them using my ol' friend a lighter and sugar, and I get a yellow (and some green) flame, which leads me to believe that what I made was actually sodium chlorate in the end, not potassium chlorate, even though I did add the potassium chloride to the mix and boil it (for a long time). but because there was some green, I am thinking that the green resulted from a small amount of blue flame (from the potassium chlorate) mixing with some of the yellow flame (caused by sodium chlorate) and also a lot of normal, unmixed sodium chlorate yellow flame. it is kind dissapointing how little I got from all this electrysis work and I even have the wrong stuff!'


One question I do have, the liquid I got out of my electrysizer was relatively clear and the potassium chloride mixture was the same clarity, when I mixed them together (you guessed it) clear. but after I boiled it, it got much yellower and greener, like the color of liquid bleach. why would this happen?

 

[pack_rat2]

KClO3 can be made by passing Cl2 gas through a solution of a K salt, or by the electrolysis of a KCl solution. Actually, it's NaCl that is normally electrolyzed to produce NaClO3. KCl is then used to precipitate the KClO3, which is relatively insoluble. You can't make it just by mixing a hypochlorite and a chloride.

 

[mrjeffy321]

KClO3 can be made by passing Cl2 gas through a solution of a K salt, or by the electrolysis of a KCl solution. Actually, it's NaCl that is normally electrolyzed to produce NaClO3. KCl is then used to precipitate the KClO3, which is relatively insoluble. You can't make it just by mixing a hypochlorite and a chloride.

I don't know how familiar you are with my epic tale of experimentation I gave walked everyone through with the last 2 pages of posts and several weeks, but I have just most recently compleated a lot of work with the electrolytic method with disapointing results, I was successfull (in making sodium chlorate), but still dissapointing none the less, even though it is suppose to be a more efficient a more recomended method of production.
In fact you can indeed making chlorate by mixing hypochlorate and chloride, I have done it, it involves a lengthy process of boiling and mixing, ..., but that has been my most successfull method so far.

I have not tried the method involving the chlorine gas, the use of chlorine gas was kind of a turn off as an option, but as I become more experienced (or reckless depending on how you look at it) in my handling of dangerous/semi-dangerous materials, like chlorine, I might decide to try it.

 

[pack_rat2]

I did a little checking on different ways of making KClO3...the bleach method works, but it doesn't involve a reaction between hypochlorite and chloride (as I thought, and knew wouldn't work); it's a thermal decomposition of hypochlorite. The purpose of the KCl is to provide K+ ions to precipitate KClO3 from the NaClO3 solution. This URL has a lot of good info:
http://www.wfvisser.dds.nl/EN/chlorate_EN.html#thermal

 

[mrjeffy321]

yes, I have seen almost that exact same page, most of the time when I refer to a spep in the process, I am referring to the instructions on that page. Using those methods, I just seem to get the best results using the decomposition method.

to make the thermal decomposition reaction between the hypochlorite and the potassium chloride, I would think it would work better/more efficently if I had a more concentrated solution of both substances, but manily the bleach solution(since it starts out at only 6%), but if I try to "boil" off some of that water and make it more concentrated, the bleach will decompose and be useless to me.

 

[pack_rat2]

The NaOCl should be as concentrated as possible, I'd think. And the KCl concentration would be unimportant, since the Cl(-) doesn't participate in the reaction to form chlorate. The reason I say that is that Cl(-) has a full octet of outer-shell electrons. It's the most stable configuration for chlorine, and it's not going alter oxidation number easily (it can happen by electrolytic methods). It's the thermal decomposition of OCl(-) that produces the ClO3(-), and the addition of K(+) causes KClO3 to precipitate out.

 

[mrjeffy321]

well the concentration of KCl might be unimportant in the reaction, but if you have a less then concentrated solution of KCl, then whrn you add it to the NaOCl, it will dilute the sodium hypochlorite solution more than necesary, idealy you would not want to add any extra solvent than necesary.

perhaps a way to increase the concentration of the NaOCl, without decomposing it first is to SLOWLY evaporate the excess water away, boiling it gets it too hot, but if you let it heat up to just maybe 20-30 degrees above room temperature, then it will evaporate away more quickly than just leaving it out in the open, and theorectically, since NaOCl is compleatly soluble in water, no mater how much you evaporate, nothing will come out of solution(but this is hard to believe).