Sciencemadness Discussion Board

KClO3 Stoichiometry questions

Manifest - 27-4-2014 at 13:12

Hello, I am planning on doing the boil down bleach method however I am unsure whether to make an equally concentrated volume with KCl or to use the stoichiometric amount in a saturated solution.
(Nurdrage says use equal volume, MrHomeScientist says use stoichiometric amount)

I am unsure whether I am doing this correctly:
First off, the disproportionation:
3 NaClO → 2NaCl + NaClO3
I have 5% bleach and I plan to boil down a litre so 5% of 1000 is 50.
50 grams NaClO = 0.67 moles

So I divide that by 3 = 0.67/ 3= 0.22 moles
0.22388794856 moles to grams = 23.83 grams of NaClO3

Next reaction is
KCl + NaClO3 → NaCl + KClO3
23.83 grams = 0.22
0.22 moles of KCl = 16.69


and 27.43g of Potassium Chlorate produced.

Is this accurate? Because that is pretty shit for a litre of Bleach.




You guys are all jealous of my scales, take the green shades off.

[Edited on 28-4-2014 by Manifest]

plante1999 - 27-4-2014 at 13:15

Looks very similar to the pratical results I had obtained in the past. Electrolysis is the way to go.

Manifest - 27-4-2014 at 13:27

Quote: Originally posted by plante1999  
Looks very similar to the pratical results I had obtained in the past. Electrolysis is the way to go.

And that is with 100% efficiency.
Electrolysis is in process. I run it from 9 in the morning from when I wake up to 10 and night, that reminds me...

It's been running for 2 days this way now at 1Amp, 6 volt

When I switch to 12 volts for a second I get 5 Amps.
I figured this would have decreased due to loss of sodium chloride, maybe not.

Anyway, should I keep being patient or how do I know when electrolysis is complete?
How much KCl do I add? Should 50g be sufficient?



[Edited on 27-4-2014 by Manifest]

plante1999 - 27-4-2014 at 13:31

Depends on you exact set-up.

Electrolysis should be kept at 3.3 to 5 V for maximum efficiency, over that you degrade your anode more then anything else.

Chemosynthesis - 27-4-2014 at 13:41

Not to nag, but it's "Cl" rather than "CL." The latter hurts my eyes.
Edit- thanks. Also, I agree with Plante99; for both chlorate and perchlorate production, electrochemistry is the way to go. I recall some friends of mine way back using industrial strength reagents to disappointing effect.

[Edited on 27-4-2014 by Chemosynthesis]

Manifest - 27-4-2014 at 13:42

Apologies, that was due to fast typing.I only do it on K̶C̶L̶ KCl
Corrected.

[Edited on 27-4-2014 by Manifest]

Manifest - 27-4-2014 at 13:53

What am I doing wrong with your formula Plante?
As per your PDF

Time(H)= ((171.6/amp)x saltm)x %100

x= ((171.6/1)*1*35 = 6006 hours?

250.25 days? That can't be right.

plante1999 - 27-4-2014 at 13:57

EDIT

I made a small mistake.

It appears I made a mistake in the equation I gave!

You should divide by the %. As such 35 become 0.35 and you divide instead of multiplying.

Total run time approx : (171.6/1) x 1 / 0.35 = 490 hours

490/24 = 20 days at 35% efficiency.

[Edited on 27-4-2014 by plante1999]

Manifest - 27-4-2014 at 13:59

No, I have got 1 Mole in my cell at a efficiency of 35%

EDIT
Oh, I see.
20 Days straight though, will I get a shit result if I continue until Sunday?

[Edited on 27-4-2014 by Manifest]

plante1999 - 27-4-2014 at 14:13

It will need 20 days straight to turn one mol of salt into one mol of chlorate with pH control at 35% efficiency with one amp. By pumping two amp it would be two time as fast.

Manifest - 27-4-2014 at 14:30

Would I not be better to apply 6 amps or would that rip the anode apart?

Should I add acid to bring the PH down?
Would Vinegar work or is it too weak?

[Edited on 27-4-2014 by Manifest]

plante1999 - 27-4-2014 at 14:41

Hydrochloric acid is better.

Depends on your anode, mmo will work at 0.2 amp per square cm of surface area. The killer is the voltage, not the amps usually.

S.C. Wack - 27-4-2014 at 15:15

Quote: Originally posted by Manifest  
I am unsure whether to make an equally concentrated volume with KCl or to use the stoichiometric amount in a saturated solution.


There are situations where double salts can be formed with excess KCl but not here I think.

Calcium hypochlorite is the way to go, if you want lots and want it today.

Zyklon-A - 27-4-2014 at 16:15

Here is some information on chlorate production stoichiometry:
http://www.sciencemadness.org/talk/viewthread.php?tid=28777&...
I agree with S.C. Wack that calcium hypochlorite is the most efficient method if you want it fast - not the cheapest, but the fastest.

blogfast25 - 28-4-2014 at 04:55

Quote: Originally posted by Manifest  
0.22388794856 moles to grams = 23.830857132675grams of NaClO3



Were they expensive, your picogram scales? :D

Zyklon-A - 28-4-2014 at 05:14

No, I struck a special deal, I got them for free when I bought the Hadron Collider!:D
[EDIT] Ah, I thought you were talking to me, I used nearly the same figures in the link supplied above.

[Edited on 28-4-2014 by Zyklonb]

Bert - 28-4-2014 at 05:58

Dang, that is one REALY ACCURATE scale there!

Say, can I borrow the Hadron collider on weekends if I pay the power bill?

MrHomeScientist - 28-4-2014 at 06:21

In my video I followed the procedure I'd seen elsewhere of combining equal volumes of boiled bleach and KCl solution, but as you mentioned I do think stoichiometric would have been better. Less water available for the chlorate to dissolve in should lead to better recovery. The only reason I can think of to have such a huge excess of KCl is maybe some sort of common ion effect further reducing solubility of the chlorate. I need to try this again with stoichiometric amounts.
I've also now done electrolysis, and it works very well. The bleach method is nice and simple, but if you have the apparatus for electrochemistry that's the way to go. I've only done one run for 24 hours, so I can't say anything about electrode life, but it went quite smoothly. It's nice to be able to just set it up and walk away while it does the work for you.

Zyklon-A - 28-4-2014 at 10:17

Electrolysis is the way to go if you want a lot.
Don't use graphite unless you want to waist a lot of time and compromise the purity of the product. I am running a cell with MMO anodes currently, and I have plenty of MMO if you want to buy some.

Manifest - 28-4-2014 at 10:34

Quote: Originally posted by blogfast25  

Were they expensive, your picogram scales? :D


Haha you guys are assholes, I didn't feel like shortening it to two digits because I copy and pasted from the Google calculator.
It's more accurate anyways.
Yes, I know how to round off, Bert.

MrHomeScientist, did you record your electrochemical synthesis? I'd love to see it.


[Edited on 28-4-2014 by Manifest]

blogfast25 - 28-4-2014 at 11:42

We're the *ssholes? You don't think using numbers like that makes you look a bit silly?

Oh well...

MrHomeScientist - 28-4-2014 at 11:56

Unfortunately no I did not record it. I did the experiment as a last-ditch, emergency bid to make some chlorate I needed for a demonstration that weekend. So I really threw it together poorly and had little time to record and edit a video. Now that I know it works, though, I'll definitely produce a video on it.
I've made a commitment to myself that I'm going to do something in the lab every weekend. This is an effort to increase my YouTube posting frequency, but it doesn't necessarily mean a new video every week (though I'd love to do that). So far, the first two weekends have been taken up inventorying every one of my chemicals and developing a more organized and formal storage system. Turns out I have 155 unique chemicals in total!

Manifest - 28-4-2014 at 12:36

Quote: Originally posted by blogfast25  
We're the *ssholes? You don't think using numbers like that makes you look a bit silly?

Oh well...


assholes in a joking, non serious kind of way, don't take me literally.

I guess it does.

@MrHomeScientist
How much Chlorate did you obtain and what was your electrodes and what voltage and current did you apply?

Is chlorate better/worse/equal to KNO3 for pyrotechnics?


[Edited on 28-4-2014 by Manifest]

MrHomeScientist - 28-4-2014 at 15:48

Here are the stats on my thrown-together chlorate cell.

Anode: MMO mesh
Cathode: Ti mesh
Immersed elecrode area: ~3in2 (~19cm2)
Voltage: 4.8V
Current: 2.55A
Run time: 24 hours
Yield: 28.5g very crude, greyish product

Detailed write-up:
I made a solution of 78.3g KCl in 260mL distilled water. To this I added 0.3g potassium dichromate dissolved in 5mL distilled water. I poured about 210mL of the finished solution into a plastic Chinese take-out container (as I said, thrown together quickly and not intended to last), and acidified the rest with 0.5mL of 9.5M HCl and set it aside. I cut two slits in the lid of this container for the electrodes, and a small hole in the center to vent (this was done outside).
I only ended up adding 1mL of the acidified stock solution about halfway into the procedure, because the volume hadn't realy appeared to decrease at all. I immersed the container in a water bath, and the solution and bath were warm to the touch throughout.
After stopping electrolysis, I capped the container with a new lid and placed it in the fridge. After cooling and filtering off the liquid, I had 28.5g of product. This is extremely crude, and is a greyish-green in color. The grey color came from some powder that spalled off the MMO at the start of electrolysis, but the mesh doesn't appear degraded at all (it was the first time I had used it). Definitely needs a recrystallization.

I have no experience with pyrotechnics, but I've heard that you should avoid chlorate and use perchlorate instead, due to its decreased sensitivity.

AJKOER - 28-4-2014 at 19:34

While the following disproportionation is widely promulgated:

3 HOCl ----) 2 HCl + HClO3

a commercial patent I have seen (see World Patent W091-03421-1, “High Purity Chloric Acid” , link http://www.google.com/patents/EP0490978A1?cl=en ) appears to imply the following scheme in a closed reaction:

3 HOCl ----) 2 HCl + HClO3
2 HCl + 2 HOCl = 2 Cl2 + 2 H2O
Net:
5 HOCl ----) 2 Cl2 + 2 H2O + HClO3

In other words, there is a possible loss of Hypochlorous acid to Chlorine so more likely around five moles of HOCl is required for each mole of HClO3 in a closed reaction chamber, and not three as is the common unqualified assertion.

[Edited on 29-4-2014 by AJKOER]

blogfast25 - 29-4-2014 at 03:33

Mr HS:

Nice write up. Remind me, what does MMO stand for?

Will you try and replenish the cell with KCl or does the whole electrolyte solution have be replaced for each batch?

plante1999 - 29-4-2014 at 03:49

mixed metal oxides, usually ruthenium and iridium oxides + titanium oxides.

MrHomeScientist - 29-4-2014 at 04:07

Yeah blogfast, the cell liquid is reusable. I'm going off woelen's excellent page on making a chlorate cell. He states that the leftover liquid can be regenerated by re-saturating with KCl, and it works a bit faster since it already has some chlorate dissolved.

Thanks for the electrodes, plante!

Manifest - 29-4-2014 at 08:25

I have some TCCA tablets out the back and Sulfuric Acid from CuSO4.

Could I bubble chlorine through NaOH with a lucozade bottle and achieve good results?
Just a thought.

plante1999 - 29-4-2014 at 08:28

There is a procedure in the PDF I made which uses potassium hydroxide, sodium hydroxide, and chlorine, you may want to try it.

Manifest - 29-4-2014 at 08:37

Is recrystallization always done with 3 times the weight of crystals? I thought it was enough to dissolve them.

plante1999 - 29-4-2014 at 08:42

Yes, and that. for potassium chlorate, is about 3 times the weight of the crystals in water.

Manifest - 29-4-2014 at 11:17

I can get 2 litres of 5% bleach for 30p or 50 cent for you.

This might work out well.

blogfast25 - 29-4-2014 at 11:34

Quote: Originally posted by plante1999  
mixed metal oxides, usually ruthenium and iridium oxides + titanium oxides.


Sounds expensive and hard to get?

Manifest - 29-4-2014 at 12:01

Not really. Zyklonb is selling them for $3 per sq.inch if you buy 2 inches or more.
Free shipping to US.

MrHomeScientist - 29-4-2014 at 12:19

They show up on eBay occasionally too, if you keep an eye out. I bought mine from plante a while back.

blogfast25 - 29-4-2014 at 12:43

So how much ruthenium/iridium do they contain? Is their presence catalytic somehow?

Zyklon-A - 29-4-2014 at 18:10
Quote:

So how much ruthenium/iridium do they contain? Is their presence catalytic somehow?

The person I bought them from didn't know what metal oxides were in it, although it has been tested to contain both ruthenium and iridium. Needless to say, He did not know the concentration. AFAIK, their presence is not catalytic. Ruthenium and iridium oxide are just cheaper than some of the other suitable inert coatings.

[Edited on 30-4-2014 by Zyklonb]

hyfalcon - 29-4-2014 at 18:28

http://www.ebay.com/itm/EXPANDED-TITANIUM-MESH-STRETCHED-SCR...

I don't know how much longer he's going to have these so you better get them while they are still available. I've got all I'll EVER need myself.

plante1999 - 29-4-2014 at 18:35

Ruthenium oxide is EXTREMELY catalytic in chlorine generation, it drops the energy needed by a so large % that it was the main reason why chlor-alkly plants invested in such research to use them instead of graphite. The coating is very thin and mostly consist of titanium oxide, a tiny part of ruthenium oxide and traces of iridium to give a longer but less efficient life to the anode.

Zyklon-A - 30-4-2014 at 06:09

Really? Well then, I guess I was wrong. I assumed there was not any catalytic property's in ruthenium or iridium oxides.

[Edited on 30-4-2014 by Zyklonb]

Manifest - 30-4-2014 at 08:07

How many sq. inches should I invest in of mmo anodes? $3 per square inch is really good.

Zyklon have you checked how much shipping is to the UK?

Could I apply 12 Volts to a MMO anode?

[Edited on 30-4-2014 by Manifest]

Zyklon-A - 30-4-2014 at 08:51

Quote: Originally posted by Manifest  
How many sq. inches should I invest in of MMO anodes?


It depends on how many amps your PSU can supply.
Quote: Originally posted by Manifest  

Zyklon have you checked how much shipping is to the UK?


Yeah, it will be quite cheap, about $1.00 as far as I know.
Quote: Originally posted by Manifest  

Could I apply 12 Volts to a MMO anode?

No! Do not use more than ~5.5 volts with MMO, above that you will start making perchlorate, and MMO can not be used for that - the anode will deteriorate.

[Edited on 30-4-2014 by Zyklonb]

Manifest - 30-4-2014 at 09:05

I'm using a DC battery charger at the minute.

I only have 6 and 12 volt options and a maximum of 6 amps.

For some reason with graphite anodes 6 volts only gives me 1 amp but at 12 volts I have 6 amps.

Will this be the same with mmo anodes? Surely 6 volt compared to 5.5 wouldn't hurt.

Zyklon-A - 30-4-2014 at 09:29

Yeah, 6 volts probably wouldn't hurt anything.
If you could reduce the voltage from 12 to about 5 then you could make a decent amount of chlorate. I don't know much about electricity, but it shouldn't be hard.
I'm not sure how much MMO you'll need, even if I knew the amps you're using because I don't know the surface area of the anode. 3 sq inches should be enough for over 6 amps I'm sure.

Manifest - 2-5-2014 at 15:08

Thank you guys so much for advice!

I made the chlorate today and achieved snow white crystals. Didn't achieve much product, mind you, but I will soon fix that.
Mixed it with sugar 50:50 and lit and it was fantastic.

Manifest - 5-5-2014 at 05:59

Boiled down 1 litre of bleach but didn't get crystals.
Instead I got this weird cloudy precipitate that floats about the solution...




Any ideas what this is?

[Edited on 5-5-2014 by Manifest]

blogfast25 - 5-5-2014 at 06:11

No, but your photo is oversized.

Manifest - 5-5-2014 at 06:28

I would fix it but I am limited to an iPad because my laptop broke.

MrHomeScientist - 5-5-2014 at 06:35

Is your bleach the generic brand, cheapest bleach available? The more pricy ones add fancy detergents, fragrances, or "stabilizers" that can interfere with chemistry use.

Manifest - 5-5-2014 at 06:46

Yes, it is the cheapest bleach at 30p for 2 litres.

Contains amongst other ingredients:
5% sodium hypochlorite

[Edited on 5-5-2014 by Manifest]