Sciencemadness Discussion Board - H2O2 and Ca(OCl)2

H2O2 and Ca(OCl)2

Sgt HAZMAT - 20-4-2005 at 02:15

Question (My first!!! Yea!)

The MSDS for calcium hypo-cholrite (Ca(OCl)2 (35%))- calls for disposal of it by mixing with hydrogen peroxide (H2O2).....

Why is this and can H2O be used instead? If so (H2O) what would the amount per lbs be and is there any contamination from this reaction to worry about?

Esplosivo - 20-4-2005 at 02:52

As far as I know hypochlorites react with hydrogen peroxide resulting in the formation of the respective chloride, in this case calcium chloride and oxygen (from the reduction of H2O2, which in this case is acting as the reducing agent). Water would have no effect except that of dissolving the hypochlorite to form a solution.

vulture - 20-4-2005 at 11:23

This reaction is going to be quite violent and exothermic though, not recommended for large batches.

How much do you need to dispose of? Oxalic acid might be a better option.

Sgt HAZMAT - 21-4-2005 at 01:48

I have about 800 lbs to get rid of. Can Water be used in stead of H2O2? And if so how much per Lbs?

cyclonite4 - 21-4-2005 at 01:59

Explosivo already explained water cant be used to dispose of Ca(OCl)2, all that would happen is the calcium hypochlorite dissolving in water.

Sgt HAZMAT - 21-4-2005 at 02:14

I was thinking that too. But then I realized that we dispose of swimming pool water in the main sewer or out on to the earth and it has a low ppm of about 2, and that is not considered a HAZ-WASTE. So if this is true how much water would it take to dilute the Cl down to that amount.....

(Can you tell I am new at this?)

sparkgap - 21-4-2005 at 02:30

Methinks a little calculation should convince you that you'd need a humongous amount of water to dilute 800 pounds of hypochlorite down to 2 ppm.

Now, 2 ppm might be considered the same as 2 mg/L. (Recall that in this system, grams and milliliters are taken as equivalent). Now, converting 800 lbs. (can you tell I prefer metric?

) gives 3.63 × 105 g.

With subsequent calculation, we require about 1.81 × 108 L!

(I'm too lazy to convert to gallons, sorry!)

sparky (^_^)

P.S. Are you sure all of the 800 lbs. are hypochlorite, or is there the possibility of inert matter being present? If so, the above calculations do not apply.

Sgt HAZMAT - 21-4-2005 at 02:35

I should have said it it only 35% Ca ( OCl )2 . in my post. I gues that would make it like a total of 250 lbs fo pure Ca ( OCl ) 2 which would bring down your numbers likewise by about 65% Though that is still a huge amount of water and what I was afraid of.

sparkgap - 21-4-2005 at 02:44

In that case, try to look into how to procure bulk amounts of oxalic acid. It doesn't have to be extremely pure; technical grade should suffice. (right, vulture? :cool:

)

sparky (^_^)

P.S. If you guys had that amount of water I calculated, spare a thought for the people who find it difficult to procure drinking water.

[Edited on 21-4-2005 by sparkgap]

Sgt HAZMAT - 21-4-2005 at 03:00

I wish we did. I am in the desert and dont have near that amount to dump on it.

Back to Sq #1

Jome - 21-4-2005 at 05:01

Wont addition of oxalic acid to the hypoclorite result in a huge cloud of Cl2 gas?

cyclonite4 - 21-4-2005 at 05:45

I second that. I guess the logic here doesnt take the chlorine (or ozone for that matter) into account. I would think the chlorine would be more of a problem.

sparkgap - 21-4-2005 at 07:23

It wasn't exactly suggested to dump the oxalic acid into the hypochlorite all at once.

But yes, Cl2 air pollution would be the new problem for this strategem.

So it's now a case of choosing between Scylla and Charybdis. Pollute the water or the air?

Something occured to me, I don't know if it's correct, but doesn't hypochlorite photodecompose? If so, maybe he can take advantage of his current (ahem) location.

sparky (^_^)

cyclonite4 - 21-4-2005 at 07:32

Air or water.... or CHILDS PLAYGROUND!!
Nah, kidding.

Why couldn't you just recycle the hypochlorite, use it for pools and such? Is it contaminated?

sparkgap - 21-4-2005 at 07:46

I don't know about him if his hypochlorite is contaminated, but since he mentions that he's in a desert, for sure there aren't enough pools of water in there for his hypochlorite to be used upon.

I don't think exporting the hypochlorite someplace else would constitute proper waste disposal either.

sparky (^_^)

P.S. There you go again with dumping stuff in children's playgrounds (like the one in the ricin thread)... what's with you?

[Edited on 21-4-2005 by sparkgap]

cyclonite4 - 21-4-2005 at 08:12

Quote:

Originally posted by sparkgap
I don't think exporting the hypochlorite someplace else would constitute proper waste disposal either.

*breaks into song*: I'ts the american waaayyyy!

What do you mean childrens playground again, I swear that was the first time I said it. Then again I may be wrong

EDIT:

Quote:

I don't know about him if his hypochlorite is contaminated, but since he mentions that he's in a desert, for sure there aren't enough pools of water in there for his hypochlorite to be used upon.

Wouldn't being in the desert be further justification to have a pool or two?

[Edited on 22-4-2005 by cyclonite4]

vulture - 21-4-2005 at 13:32

Won't the calciumhypochlorite oxidize the oxalic acid to CO2 and H2O, just like KMnO4 does?

Dave Angel - 21-4-2005 at 15:00

How about thermal decomposition?

The temperature doesn't have to be very high; 177°C, and the reaction is exothermic and thus could be moderated to be self-sustaining.

Some sources state that the only hazardous decomposition product is oxygen, whilst some give chlorine and chlorine monoxide also. The latter two may come at higher temperatures or perhaps they are decomposition products of pathways other than thermal.

Sounds like a solar furnace project is in order - perfect location and motivation!

Well, at least a few experiments with a propane stove...

Pyrovus - 22-4-2005 at 00:46

Won't that give Ca(ClO3)2?

azaleaemerson - 22-4-2005 at 04:54

I suggest dissolving in water and mixing it with a reducing agent. Swimming pool places sell "anti-chlor" which is sodium bisulfite. The end products will be sodium chloride, sodium sulfate, and water.

Sgt HAZMAT - 22-4-2005 at 05:26

Now that is an interesting idea!!!

cyclonite4 - 22-4-2005 at 06:09

That is a good idea, but what to do with the byproducts after that?

sparkgap - 22-4-2005 at 06:36

I am utterly confused; which idea was our HazMat manager referring to: the solar furnace idea or the bisulfite idea?

I'm still skeptical with the bisulfite, since water is apparently a precious commodity in the desert... how much would he then need to use? In other words, how soluble is hypochlorite mixed with bisulfite in water? But maybe, just maybe, the diverse ion effect can be in his favor.

sparky (^_^)

Sgt HAZMAT - 22-4-2005 at 06:43

I was refering to the bisulfite.

Oh and we do have water here, just not millions of Gals to throw at something.

Dave Angel - 22-4-2005 at 07:40

Quote:

Originally posted by Pyrovus
Won't that give Ca(ClO3)2?

Do you know that for sure or are you just tossing thoughts around? Are you thinking it might be a disproportionation?

Do say so if you are certain!

I'm not sure myself; the point of an experiment would be to find out!

Esplosivo - 22-4-2005 at 07:46

Being a hypochlorite I suppose that on heating >70 deg C it would disproportionate in the same way sodium hypochlorite does. The passage of chlorine through hot, conc. calcium hydroxide was at one time the method of production of chlorates, the calcium chlorate produced being reacted with KCl and the KClO3 crystallized.

Edit: I don't suppose this had anything to do with the thread except to show that calcium hypochlorite cannot be decomposed by heat, although I do think that water is required for a disproprotionation to occur.

May I suggest bubbling carbon dioxide through a conc. solution of calcium hypochlorite in an isolated site. This would produce carbonic acid which would probably react with the hypochlorite to give chlorine (you're in the desert, so the small quantity given off over a long time should not be a problem) and calcium carbonate, which is surely not a problem to dispose of. Somebody correct me if I am wrong.

[Edited on 22-4-2005 by Esplosivo]

sparkgap - 22-4-2005 at 08:11

Esplosivo, nice suggestion, but methinks he'd have to apply pressure of some sort so that an appreciable concentration of carbonic acid is present. Besides, normal daytime desert temperatures tend to disfavor dissolution of gases into water, but maybe a cooling system of some sort can rectify this, or they can run it in the nighttime, when the temperature is more agreeable.

What is the Henry's law constant for CO2 anyway?

sparky (^_^)

Esplosivo - 22-4-2005 at 08:25

I am no university chem student (in fact I am more of the biochem/medicine guy - lets see next year), but according to my poorish knowledge of Henry's law constant (which I did not do at school), the inverse of this constant multiplied by the partial pressure of the gas above the solution should give the molar solubility. Now assuming that carbon dioxide gas is at one atmosphere above the solution (Henry's constant being 29.76 atm/(mol/dm3) at 25 deg C) the molar solubiltiy should be about 0.034moles/dm3.

More would dissolve as more of the CO2 reacts with the hypochlorite, since the dissolved conc. of CO2 decreases. I suppose a cooling jacket would be necessary to increase solubility.

IIRC, this fact about carbonic acid decomposing is why the solid calcium hypochlorite smells of chlorine, but I might be mistaken.

[Edited on 22-4-2005 by Esplosivo]

neutrino - 22-4-2005 at 13:07

Actually, the bisulfite would form sodium chloride and calcium sulfate, which would precipitate. Don’t try filtering it out, though, as CaSO4 forms a gelatinous mass that is almost impossible to filter out in this form.

A wild idea (it probably won’t work, though) goes as follows: add sodium sulfate to your calcium hypochlorite solution. Spread out the resulting gelatinous mass in the sun. The sodium hypochlorite will decompose while drying, leaving sodium chloride and chlorate. I’m not sure how hazardous those are, though.

Ca(OCl)2

MadHatter - 24-4-2005 at 23:07

Sarge, if you're in a desert, I would try baking it in the sun. I don't know how long it
would take but eventually it will decompose into chlorine and calcium oxide. Of
course, I also don't know what environmental regulations you're bound by either.

In a way I envy you. Personally, if I had to dispose of 800 LBS, I'd dissolve it in water,
boil it for 30 minutes, throw away the chloride, and keep the chlorate that's left.
Yes, the hypochlorite, boiled in water will thermally decompose into the chlorate and
chloride. Check Wouter's page about that one.

sparkgap - 24-4-2005 at 23:19

A little ponderance for our intrepid HazMat manager:

Should you end up converting your hypochlorite to chlorate, you may not want to dispose of this in or near an area with a plant population, since chlorate is a nice total herbicide.

sparky (^_^)

frogfot - 16-7-2005 at 06:09

Is there a way to decompose aqueous hypochlorite without changing the pH in solution?

I'm trying to estimate OH- concentration in chlorate cell electrolyte by titration with phenolphtalein as indicator.. but the indicator discolors too fast.. Oh, and heating it event for 0,5 hours doesn't help..

How would for example H2O2 or sodium formeate react with hypochlorite..?

verode - 2-8-2005 at 19:31

try with urea CO(NH2)2 + water
or Na2SO3

Sgt HAZMAT - 2-8-2005 at 22:20

We are thinking of a unique solution. Keep those ideas flowing!!!

vulture - 3-8-2005 at 01:48

You're in the army right? Can your kitchen unit donate about 100lbs of sugar to you?

Mix the stuff, then call the EOD, tell them you have some unstable old rocket fuel and they'll probably end up blowing it right there in your desert.

You have alot of fun and get an easy disposal

neutrino - 3-8-2005 at 11:21

Urea can react with hypochlorites to form explosive NCl3.

praseodym - 4-8-2005 at 22:43

Or you can bubble chlorine gas through a solution of ammonium nitrate to get NCl3. NCl3 is exciting as it is very reactive and explosive but storage could be a problem as it is easily decomposed into ammonia and chlorine due to its high unstability (especially when it is pure).

neutrino - 5-8-2005 at 04:02

We're trying to avoid anythig dangerous here. Several dozen liters of ultra-sensitive high explosive isn't something you want to have to deal with.

sparkgap - 5-8-2005 at 06:16

praseodym, he's going for a way to safely dispose of hypochlorite... jeez... FCOL, he's a freakin' HazMat Manager!!!

He'd be in deep shit for trying that stunt of yours...

vulture was taking the damn piss...

sparky (~_~)