runaway rxn

[Ctrl_C]

i was making ap last night and i did something stupid...i added the HCl before placing the reactant vessel in an ice bath. it was fine for about a minute and then it started bubbling and got extremely hot. i quickly realized the problem and dashed to the bathroom sink, filled a measuring cup with water, and dumped it in to stop the rxn. it was too late though, the room quickly filled with HCl gas that burned my eyes, nose and throat like you wouldnt believe. me and my friend evac'ed the room, open the window and closed the door. it took a full 2 hours to vent the gas.

just a little warning to watch what you're doing no matter how many times you've done it before. treat every time like your first.

[c0deblue]

Pretty scary when that happens, not to mention the subsequent corrosion of everything made of steel from the acid fumes.

It's been years since I've fooled around with homebrew stuff, but I found that a large flat rectangular pyrex dish (like for lasagna) provided good temperature control. Nested in a plastic dishpan full of ice, it stays nice and cool since the depth of the reactants is only 3/8 of an inch or less. Use a plastic spatula to keep things mixed, or for the rougher reactions just a piece of window glass ground smooth on the edges.

[CragHack]

Ctrl_C what was the concentration of your HCl? i have seen 30% used in conjunction with 3% peroxide and acetone... about 50 ml's was dumped in all at once and the reaction vessel (non pyrex glass) only got slightly warm... how concnetrated was the H₂O₂ in the reaction? that could have something to do with it. although i don't think the reaction produces HCl gas anwyay so i have no idea what happened. i was assuming that high concentrations premoted a fast reaction, all be it this will happen, like i said this reaction, i don't think, gives of HCl gas... hmmmmm. perplexing.

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[Ctrl_C]

oh it was HCl gas alright. my guess is that it got so hot that the HCl boiled releasing HCl vapor. i was using muriatic acid (36% HCl) and baquacil (30% H₂O₂

[CragHack]

how much HCl did you use? and did you add it all at once? did you make sure to clean out the reaction vessel before you started the reaction? the only problem i can see is the concentration of the H₂O₂ was too high in respect to the amount of HCl added, and possibly the speed at which it was added. now that i think about it i think the high concetration of your H₂O₂ is probly to blame. when you dumped in the HCl (i am assuming you dumped it in all at once) the reaction started off immediatly and very hastely to boot. next time you do it, try and water down your H₂O₂ to make a lower ocncentration OR add in the HCl little by little while the vessel is in an ice bath. that should stop future happenings of this nature.

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[This message has been edited by CragHack (edited April 02, 2001).]

[SATANIC]

I can't see why this woould happen. I never use an ice bath or the fridge, and this has never happened. I am sure there has never even been a temperature change. There must be some other explanation.

[Anthony]

H2O2 + acetone = heat
Acid + water = heat

Even using low conc (6%)H2O2 when added to acetone the solution gets a little warm, obviously the higher the conc of the H2O2 the more violent the reaction.

[CragHack]

thats what i said just in more words. anyway, if you want to avoid this in the future take my advice above. cut the H₂O₂ with water.

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[PHILOU Zrealone]

There is no mention also about the quantities!
So making 10g is not the same as making 100g nor even close to make 1kg!
Scaling up is not a trivial thing and in all the chemistry accidents were reported on industrial scales by a simple multiplication factor of 2, yes 2!
So making without any problem 10g will never garanty you to succeed making 20g with the same appartus!!!! Heat dissipates much slower in a big batch and thus can accumulate generating hot spots and ... sometimes BOOM or runaway! Knowing that heat comes from an exothermic reaction and that every 10C those reactions speed up by a factor 2!!! Keep this in mind!

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"Life that deadly disease sexually transmitted".
"Chemistry is all what stinks and explode; Physic is all what never works! ;-p :-) :o)"

[Demolition]

Ctrl_C,I have had the same thing happen to me but only I was making HMTD.After leaving the hexamine to dissolve in the Hydrogen peroxide for 30min I then added 30mls of 30%HCl and then stirred for a little while with a metal teaspoon(stupid me).I then started to carry it to the fridge when it started to bubble,I thought FUCK!,I then sat it on the ground because of the heat(in the garage),then it started to boil,I quickly grabbed it and sat it down outside.I then watched it for a minute from a few meters,it got so hot that it cracked the bottom of the glass jar and ran away into the drain.By that time my eyes,nose,throat and fingers were all burning from the HCl gas.I them spent about 1/2 an hour washing my eyes,hands and drinking liters of water.That was about 3 months ago and I haven't made anything since.It just goes to show how dangerous impurities can be in explosive peroxides.
And as Ctrl_C said,treat every time like your first.
Demolition

[blackadder]

Hydrogen Chloride gas is bloody toxic, you're lucky you didn't have anything serious done to you, people would find out that you were making explosives, and that would get you on the news:

"A xx year old man was seriously injured 3 nights ago while making explosives in his home. While making the explosives, (name) breathed in hydrogen chloride, a toxic gas, blah blah blah blah blah blah blah"

you can see what I'm getting at.

[Demolition]

I'm not sure if the gas caused it but after I breathed in the Hydrogen Chloride Gas my left arm started to go num.Now it just may of been that I was extremely nervous but It scared the shit out of me.
Demolition

[CragHack]

the gas replaced the oxygen with HCl, i bet the cells in your left arm didn't like that too much. so they went nuts. not to technical but i think you get it. i would bet on the fact it was due to the gas.

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[era5or]

The gas was Chloracetone(not HCl), it is the earlier variant of CS-Gas.

[Tony Montana]

I dreamed of my first runaway reaction last night. I foolishly tried to make RDX with 70% HNO3. Despite all the warnings that your HNO3 has to be free of ALL water, I tried anyway. Using 30% more HNO3, I mixed 55grams of C6H12N4 slowly, it took 3 hours for the C6H12N4 to completly dissolve as small amounts would cake together and float to the top. After all was dissolved I stirred vigorously for 10 minutes, then proceded to slowly heat the solution to 55*C. The problem pretty much started then, the solution got to 55* then after removing from heat, 60* then in the ice bath 65* 70* 75* then I dumped all I could in cold water which stopped the reaction of what was dumped.[I cannot explain how much heat this flask produced, after putting in an ice-bath it melted two trays worth of ice cubes within 1-2 minutes]What little solution left in the flask fumed intensely with dark red fumes while it was bubbling up the sides of the flask.
Outcome: Sore eyes, sore throat, wasted 55 grams of C6H12N4, wasted about 250ml of 70% HNO3, left with alot of chemical waste to dispose of and an all over feeling of disapointment.http://theforum.virtualave.net/ubb/smilies/frown.gif

[Mick]

well, i've only had one runaway AP

i mixxed up a small batch of AP and picked up something to stir, i put it into the jar and started to stir it, only to realise i had picked up a an aluminium rod (AL + HCI = bad)
and it started to bubble and fizz so i just picked the jar up and therw it out the door onto the grass

and amazingly when the jar hit the ground it landed standing up so i watched it bubble a fizz - getting more fierce by the second and after about 3 mins aluminium rod dissapeared, and it kept bubbling for a good 10mins longer

scared the shit out of me when that happened..put me off making AP for a good 10 mins after that =D

[BrAiNFeVeR]

Well, i haven't experienced things like that (thanks to this forum ;-), but i do use a metal rod for stirring ...
It's an guidence axle (sp?) for an ancient disc-drive, so it's of a high quality alloy (i hope) is this ok ??

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"Mess with me, and you'll end up with a .44 under your chin and your brains on the ceiling"

[Tony Montana]

NOPE!!! When making AP or HMTD never use anything metal in contact with them(I have used a plastic spoon a couple of times with HMTD). Even using high concentration acids with metal is very bad idea.
BRAINFEVER: Your best bet, is a thermometer, get one from a labratory supply store. They will cost under $20, they are made of glass, and they dont react with anything. While stirring you can also pay close attention to temperatures of reacting compounds, which proves to be most beneficial when things like in the above posts happen.

[BrAiNFeVeR]

Ow, I think i will stop stirring with that thing then ...
But i tought, if i can put it in 60% nitric acid and nothing happens, it would be safe, i guess not then ...
So far i've been very lucky to find some lab-equipement (graded cilinder, erlenmeyer flask, ...) i'll see if i can find a thermometer (can't be that difficult) ;-)

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"Mess with me, and you'll end up with a .44 under your chin and your brains on the ceiling"