If I concentrate it by boiling, will I have to collect the vapors and allow them to condense into liquid again, or do I simply boil off the water?

I've also heard H2O2 can be concentrated by freezing. The water freezes before the H2O2 does, so as more ice builds up the concentration increases. Has anyone done this? How effective is it?

By the way, my peroxide is only 3%. I have a lot of it though.

I've used both methods before which resulted in a useable concentration for making MEKP. I think boiling might be better though, or actually heating it to near boiling but never let it actually boil just let the water evaporate.

Just boil off the water. The H2O2 will be left behind, and the water should evaporate.

Im not sure about the freezing point of H2O2, but I think that they are pretty close, so boiling it would be much easier.

Which ever way you choose, do not go past 30-50 percent. It becomes very reactive, and after 70-80 percent it is an explosive on its own.

i just freeze and boil mine but i also have a regualr supply of 30% H2O2

by freezing you have to keep an eye on it and pull the thin layers of ice off when they form ...

[This message has been edited by warweed12 (edited 07-28-2003).]

I was in the middle of boiling 1000 ML of H2O2 when my mom came home, got all pissy and dumped it all out, even though she knows I make black powder cobs and doesn't do anything about that.

I've got a few questions about the boiling process.

#1. When you boil it does the water evaporate and leave behind crystals or does it leave the chemical in a more purified(sp?) form? I was thinkin it's the 2nd one but I'm not sure

#2. How do you know what the purity of the H2O2? I don't want the purity to become to high but I am unsure of how to measure it so i know when to stop boiling.

#3. How do you know when the water has all evaporated? Is there a tool to check the H20? Or do you judge it by comen sense.

[This message has been edited by pyroCHAD (edited 07-29-2003).]

Uh, if you can't figure out the basics of boiling the water off of a hydrogen peroxide solution then you should wait a while before trying to make an organic peroxides. Your first question indicates that you think H2O2 is a solid(it's actually a liquid). The second question is pretty obvious. You're boiling off the water but not the H2O2 so you just reduce the volume by however much you you want to multiply the concentration. 100ml of 3% when boiled down to 10ml is then 30%(theoretically). Your third question is just a different way to ask the second one.

Ok thanx,

No worries though, I am just wondering about it.

I am gonna work my way up to that stuff so I don't lose an appendedge.

whats the use for the stuff left over from h2o2?

It's a stronger, more sensitive, and more concentrated form than normal.

Scroll down in the threads and look for the Easy Fireball thread.

You'll learn more there

Ok hydrogen peroxide in its natural state is a liquid, not solid (crystals). Second water boils at 100*C and h202 at 150*C. The freezing point for h2o is 0*c and for h202 is I think -.4*c. Very close, but the temp should stop at 0 until all of the water is frozen and then start to climb up and start freezing h202.

So for example if we wanted 30ml of 30% h202 we would measure off 30ml of water and pour it into the container and then mark the water line. Then we would spill that out and add 300ml of 3% h202 (we want it 10x stronger so we add 10x as much) and pop it in the freezer. Then you would every once in a while remove ice from the solution with tongs or whatever and keep doing this until the volume of the liquid reachs that mark you amde earlier. Bam you have some 30% h202 now.

Also I have the same problem, I don't have the time to sit around steaming something.

BTW, if you are using the freezing method, make sure to stir the H2O2. Moving liquid actually freezes quicker, so it will take much less time for the water to become solid.

I was reading some stuff about concentrating H2O2,

and it said something about it and it said.

Hydrogen peroxide is not flammable, but concentrated solutions may undergo violent decomposition in the presence of trace impurities or upon heating.



and it also said

First, steam explosions are easy to occur if the H2O2 is not pure or some contaminants get into it.

so I am wondering what it meant when it said,

"violent decomposition".

I am also wondering what type of contaminants were they talking about that could get into it?

http://krimzonpyro.com/ep/projectsdevicesdir/boilingh2o2test.html

Whoops, sorry.

Thank you

I tried to steam h202 once. It was taking so long so I cranked up the heat and it exploded.

i tried to freeze some h202 and i didnt check for ice often enough so i left it in my garage uncovered. now a few weeks later i am taking another crack at it. can i use the same h2o2? (did the h2o2 evaporate off making it worthless)

[This message has been edited by Dgetch (edited 07-30-2003).]

Here check out this link, and scroll about 2/3 of the way down, and look for the section about freezing.

And I wouldn't advise using the same h2o2. http://webhome.idirect.com/~earlcp/FAQs/FAQ.html

Tell me how it works out for ya

thanks that site helped. i bought some more h2o2, got about half done with the freezing ,my mom saw it in the freezer, flipped out and dumped it. i will try again when she isnt PMSing.

i had no problems freezing it though.

Doesn't H2O2 decompose at higher temperatures? If so, wouldn't you get a better yield with freezing?

As for freezing, what you want to do is crystalize out the water, try immersing a pan of H2O2 in a bath of ice and salt water. That way you can moniter the temperature better than just sticking it in the freezer.

Then again, that's just if you want to put the effort into getting a slightly higher yield.

Decomposition does occur at a slight rate as you boil off the water. By reducing the volume 10 times you are not quite getting it to 30%

A much easier way would be spent looking around trying to find a source of 35% peroxide. I can pick up 4 liters for 16 dollars canadian.

It's used as a wood bleach isn't it?