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Author: Subject: Stupid Mistake - A Warning to All
mick
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[*] posted on 23-10-2003 at 06:24
sulphuric acid


er, is this a wind up
If you do not know how to dilute sulfuric acid then be careful with everything else you do.
In chemistry adding A to B is completely different from adding B to A, which one is safest in excess.
Try pouring a gallon of petrol on to a fire rather than adding the fire to the petrol.

Pure sulfuric acid boils at 330oC, density 1.84
H2SO4.H2O boils at 290oC, density 1.79
H2SO4.2H2O boils at 167oC, density 1.65
etc
Water boils at 100oC, density 1
Water + the above= lots of heat
So if you end up with a lower layer of conc sulfuric acid with water on top it is stable until you touch it.
Then the water does not just boil it vapourises with pressure, splashing the stuff every where. I have never heard off a successful blind practical chemist (a few fingers missing and scars OK).
When I have diluted conc sulfuric acid, I have added the acid slowly and carefully to stirred ice or ice+water (1 gram ice= 1 ml water) with external cooling, keeping my face well away, even with goggles on and I have only got cigarette burns on my clothes.
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vulture
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[*] posted on 23-10-2003 at 08:17


Cigarettes & chemistry = bad idea...:P

Not only hazardous in the lab, but as a chemist you should realize what toxic nasties it produces.

Hell, smoking a cig is worse for your health than being exposed to all sorts of chemicals in a lab using normal safety precautions.

You won't inhale any poisonous chemical fumes on porpuse, now huh? But you are doing it when smoking a cig...:P




One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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palpy
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[*] posted on 23-10-2003 at 08:42


Quote:
Originally posted by mick
I have never heard off a successful blind practical chemist


Well, this reminds me of a well-known case from my country:
Some guy and his friend were dismantling a WW2 hand grenade. It went off, the friend was killed and this guy lost his arm and was blinded. This happened in some late 1950s !!!
But the man has been regularly making AP to recent days. (BLIND! and ONE HANDED :o ). He damaged his house several times (cos he had been drying the AP on the hetaing!) and was also a few times arrested. And still he refused to stop making explosives...
I heard on the news some year ago, that he had finally lost his other palm, so I suppose he would stop at last.

These people are really dangerous... :)
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dragora
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[*] posted on 15-11-2003 at 01:10


i read somewhere that very pure ap i as low as sensitive as petn, it was a paper about analysyng remnants of explosives(forensic analysis)and ap leaves almost no remnants after detonation
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AndersHoveland
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[*] posted on 2-2-2013 at 16:35


Quote: Originally posted by Backyard Blaster  
Actually, I throughly read the labels before I even bought the stuff. It only says "CONTAINS SULPHURIC ACID", and does not specify the concentration. I think it's a safe bet that it's at least 90% pure. I assume the red coloring, is to make spills easier to identify and clean up.

More likely it is of 30% concentration. "Concentrated" means different things depending on the context. In chemistry, "concentrated sulfuric acid" often refers to >97.5%, but for safety labelling it is usually much less. A concentration of 30%, with a red dye, is actually quite common for commercial and industrial purposes. I actually happened to find just such a bottle in a trash bin one time behind a supermarket. I am guessing a pool maintanence worker illegally dumped it there.




I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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Simbani
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[*] posted on 2-2-2013 at 16:56


nearly 10 years later.. :D
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AndersHoveland
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[*] posted on 2-2-2013 at 21:02


Another reason for the exothermic reaction may have some relation to the fact that acetone can actually be slowly oxidized by hydrogen peroxide. This is much more rapid under alkaline conditions (sodium bicarbonate).
"The Journal of biological chemistry", Volume 35, (1918), p90-91

The explosion of acetone peroxide actually proceeds through a radical mechanism, so probably the vigorous decomposition of mixtures of acetone and hydrogen peroxide in solution is somewhat similar.

The decomposition products from acetone peroxide where studied in toluene solution heated to 173 °C. Various different products formed, including radical reactions with the solvent, but 85% of the acetone was recovered unoxidized.
"Thermal Decomposition Reaction of Acetone Triperoxide in Toluene Solution", Gladys N. Eyler, Carmen M. Mateo, Elida E. Alvarez, and Adriana I. Cañizo, (Argentina)
J. Org. Chem., 2000, 65 (8), pp 2319–2321


[Edited on 3-2-2013 by AndersHoveland]
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chemrox
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[*] posted on 2-2-2013 at 22:59


DO NOT BLAME THE LABEL YOU SNIVELING PANSY!
When you go fucking around with strong mineral acids and primary high explosives expect to get hurt and be appropriately cautious you twit. (I think he should be banned for not taking responsibility.)




"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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Farnsworth
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[*] posted on 2-2-2013 at 23:45


Quote:
go look for HNO3 at agricolture reseller, they use 55% conc for correcting the soil acidity adding NO3 at the same time, kinda cheap, 10 bucks for one gallon...


Anyone have more info on this? Google is returning bupkiss.
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mayko
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[*] posted on 3-2-2013 at 09:33


Glad you are okay, but eesh. I can vouch that the label might not give a concentration (mine doesn't) but a bit on sugar will confirm that it's the Hard Stuff.

It sounds like you might not have been wearing splash-resistant goggles? If not, they are like $1 at a hardware store. Find a place in your lab for them, print this out, and tape it next to that place.


It sounds like you might also have some lighting issues in your lab. Fix that before you do anything dangerous.

I second earlier posts on different rxns to be running at this point in your adventures. First off, is every chemical in your lab labeled? Go through and read the wikipedia page for each one and make your own label with information you think is important. Then, maybe start with some simple reactions. Heating sodium bicarbonate to form sodium carbonate is fun; the outgassing is kinda hilarious, and you get acid neutralizer as a product :D Purifying iodine from povidone is pretty fun too. Are you keeping a notebook?

I didn't use H2SO4 at all until relatively recently, so I'd never got in the habit of "add acids to water, not water to acids". I was doing an iodine purification when I relearned that one. Volcanic indeed.


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barley81
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[*] posted on 3-2-2013 at 10:12


H2O2 + H2SO4 makes piranha solution which eats up everything including acetone (atomic oxygen might be involved). It should be used very carefully because it's dangerously strong. I found a fritted funnel with a brown ugly stain that wouldn't come off with a night soaking in conc. H2SO4, but piranha solution made the frit fresh & clean in minutes!

This incident reminds me of one I found on the web at http://yarchive.net/chem/piranha_solution.html


Quote:
A classic lab accident with piranha solution occurred at Cornell in 1986 or so. The grad students in one lab used to rotate responsibility for cleaning all of their glass frits by running piranha solution thru them (using "house vacuum") into a filter flask. One student made the mistake of leaving a trace of acetone in the flask. When the piranha solution hit the acetone, it went BLAMMO and a million pieces of glass embedded themselves into her face. Thank heavens she was wearing her safety glasses or she would most likely be blind now: the lenses in her safety glasses were shattered but still intact in the frames. The chemistry department took a photo of the glasses and used it in their "Are you wearing your safety glasses?" poster for years afterward. Not surprisingly, the student decided to leave chemistry after her hospitalization.


[Edited on 3-2-2013 by barley81]
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Fantasma4500
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[*] posted on 13-2-2013 at 11:29


you should never EVER use H2SO4 for synthesizing this compound as it heats up strongly, and will cause it to form dimeric in any way.. a tiny bit but you dont need much to set off as much as 1 kg..
never ever just proceed to pour in chemicals you dont know concentration of etc. another person was fooled to think a lab glass he bought was heat resistant glass, but it wasnt.. it was cheap chinese look alike pyrex, cost him 2 hands and perhaps even some more of his arm if im not wrong..




~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
http://www.trimen.pl/witek/calculators/stezenia.html
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Ral123
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[*] posted on 13-2-2013 at 11:53


Safety is a state of mind. Quality glassware, reagents and avoiding organic peroxides is just an addition. H2SO4 for AP is super redneck. Don't do it unless you will triple recrystalise your product after. Only distilled/deionised water, nice reagents and cool to -10 before mixing. After mixing, put in freezer again. I'm pretty sure in April I'll report my 1 year old AP with no signs of decomposition(super dangerous trough).
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Adas
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[*] posted on 13-2-2013 at 12:18


Quote: Originally posted by Ral123  
Safety is a state of mind. Quality glassware, reagents and avoiding organic peroxides is just an addition. H2SO4 for AP is super redneck. Don't do it unless you will triple recrystalise your product after. Only distilled/deionised water, nice reagents and cool to -10 before mixing. After mixing, put in freezer again. I'm pretty sure in April I'll report my 1 year old AP with no signs of decomposition(super dangerous trough).


I also have a few milligrams of pretty old TATP :) It is more than a year old, but I don't remember when I set this sample aside. Maybe I will test the sensitivity soon.




Rest In Pieces!
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Ral123
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[*] posted on 13-2-2013 at 13:56


Yes it's as sensitive as new HMTD. Tell us is it still nice crystals. Does it smell like medicine? If it's that old leave it to see how long will it last. How did you prepare it?
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Adas
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[*] posted on 14-2-2013 at 08:32


Quote: Originally posted by Ral123  
Yes it's as sensitive as new HMTD. Tell us is it still nice crystals. Does it smell like medicine? If it's that old leave it to see how long will it last. How did you prepare it?


No, it still smells like a new sample. I tested the sensitivity right now, it doesn't seem to have changed. It was a standard preparation using tech. grade HCl and washed very well with water (I use old sock as a filter, very little particles pass through and water goes through like nothing).




Rest In Pieces!
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Variscite
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[*] posted on 27-5-2013 at 07:56


Were you even wearing eye protection?
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amazingchemistry
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[*] posted on 27-5-2013 at 20:21


My two cents with respect to safety:
First of all READ THE MSDS. All chemicals (even drain cleaners) are supposed to have one. Wear Eye protection at the very least, and appropriate gloves and lab coat if possible. Don't blame the literature for this accident. It is not the literature's purpose to advice you about safety.
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[*] posted on 27-5-2013 at 20:35


As we all know here, MSDS are not your ideal source of information, yes, it is a good rough outline to go off, but often wrong. I know from personal experience that particularly concentrations and other percentages are sometimes wrong. H2O2 which is clearly labeled 7% is 3% on the msds... :o
Moflo drain cleaner is labeled different as well.
Sorry for not pulling up links guys, I'll probably get shit for that.




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[*] posted on 28-5-2013 at 22:54


More protips:

The blue nitrile gloves you used in Wednesday's KMnO4 titration lab aren't any good against a mixed-acid nitration mixture. Wear LDPE gloves (the crinkly transparent kind that the Sams Club free sample people wear) over the nitrile for real protection.

If you are using a nitrate salt/sulfuric acid mixture to nitrate something, assume it is giving off nitrogen dioxide even if you can't see it. You don't need a reeking reddish-brown cloud of death to destroy your lungs; It's just faster that way. To convince yourself, leave an open container of strong ammonia water next to a container of mixed acid and observe the previously invisible deadly vapor become only slightly less deadly white fog.

If you are using store-bought cold-pack nitrate salts, recrystallize them first to prevent horrible side reactions that will render your product either useless or insanely dangerous. Blame the meth heads for the inconvenience.

Never put a nitrate salt in the microwave.

Even if you think your ammonium nitrate is dry, it probably isn't. Warm it up again until it partially deliquesces, then filter while warm and rinse with cold acetone, then blow-dry until the ketone smell is gone. Bake in the oven at 110 Celsius for another hour to be sure.
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[*] posted on 29-5-2013 at 08:45


Quote: Originally posted by Backyard Blaster  
Hopefully by sharing this experience I can spare someone else from perhaps serious injury.

Look at this thread for a serious disaster involving explosives (ETN).
http://www.sciencemadness.org/talk/viewthread.php?tid=22554




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