miamicanes
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Picric Acid disposal
A few days ago, I was really happy about discovering a seemingly trivial way to synthesize Isatin from synthetic indigo and nitric acid.
Then, after finally finding places that would sell me the synthetic indigo, nitric acid, and the equipment to react them, I finally got around to
looking up the reaction's waste product: Picric acid. Eeeek.
Is there anything readily-available that I can react with the picric acid to at least render it non-explosive until I figure out how to get rid of it?
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JohnWW
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Probably the safest way to dispose of it would be to bury it deeply. In the meantime, you could render it safe by dissolving it: picric acid is
soluble to the extent of 1.23 parts/100 parts water, and 6 parts/100 parts ethanol, at 20ºC.
John W.
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The_Davster
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Picric acid is not that explosive, it requires a lot of force to go. But, as John WW says, just dissolve it in water and you will be fine.
About how much picric are we talking about here?
[Edited on 1-10-2004 by rogue chemist]
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BromicAcid
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Some ideas and some googleing:
| Quote: | | If you decide to dispose of your wet picric acid, several options are available. First, you could try reducing the picric acid to a non-explosive form
using sodium hydroxide and sodium sulfide (18). After this treatment, the material will still be toxic and have to be disposed of as hazardous waste.
Alternatively, it could be manifested as a flammable solid for hazardous waste and disposed of by incineration. DO NOT pour it down the drain; it
could react with copper or iron piping to form the explosive salts. |
From Here
A thread titled "Help! Picric acid disposal!" found in the groups section of google.
There are a number of other areas of intrest if you go to google and search picric acid disposal in the groups section.
Maybe you could dissolve picric in HCl and add tin to it to reduce it to the analine deriviative, but who knows how stable tin picrate is, might
explode on the spot if too saturated.
But then again your method of disposal is going to depend on how much you have, you're going to have to do it in small amounts no matter what to
just be safe.
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Marvin
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The primary thing is to make sure you dont form picrate salts, particually of sodium or potassium or transition metals.
Picric acid free from salts under say 10% of water is essentially safe from explosion. Picric acid resulting as a by product, Hmm.....
If you are more paranoid you can always react the acid with aq ammonia, the ammonium salt is comparable to ammonium nitrate in terms of sensitivity.
You still have the problem that contact with metals (eg containers) or salts of other compounds can form unstable picrates. Aside from toxicity
issues this is the only thing I'd be worried about.
If I wanted rid of it, I would probably neutralise with ammonia and then burn it in small portions. If I wanted rid of the pure stuff I'd
probably just burn the acid unchanged (also in small portions) keeping any larger amount a considerable distance from the fire.
Burying it is not a good option in my opinion. A cross between a potential future landmine and killing plantlife.
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miamicanes
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| Quote: | | About how much picric are we talking about here? |
Hmmm. That's a good question. I knew how to balance equations and calculate yields 10 years ago when I took chemistry in college, but I
haven't had time yet to re-learn how to figure it out (it's on the agenda for this weekend's crash course in re-learning enough to do
the project next week when everything arrives).
Ideally, I'd like to wind up with about 25g of usable Isatin (enough to last for a couple of months, since it looks like making the Isatin is
going to be a major pain). But I might settle for 5-10g the first time around if it looks like I'm going to wind up making huge amounts of picric
acid to get a tiny bit of isatin.
I guess the unbalanced reaction is something like:
C16H10N2O2 + HNO3 -> C8H5NO2 + C6H3N3O7
For the curious... I'm experimenting with Isatin-based hair dye. Basically, you dissolve 1-1.5g/Isatin and 1g 4-Aminophenol in 30mL Ethanol,
dilute it with 70mL deionized water, and add a bit of gum arabic to thicken it a bit.
By themselves, the chemicals don't do much. But when brought together in contact with hair, something in the hair acts as a catalyst and rapidly
develops it into dark yellow-brown more or less permanent dye.
The main benefit is the lack of staining (it only forms color inside the hair and has minimal affinity for skin, unlike normal permanent color which
stains badly if you dare to leave it on long enough to make the roots match the rest).
The main drawback is the fact that the reaction only works with a tiny subset of arylamines -- none of which are capable of producing blue or green,
which basically means it's only good for medium to dark brown. From what I've managed to discern, the company that developed it decided it
was basically a cool demonstration, but wasn't a viable mass-market product & didn't really fit into their grand product strategy. Well,
that, and the fact that by necessity it has to have a fairly volatile alcohol base, which probably sent their liability lawyers into convulsions at
the thought of someone lighting up a cigarette, product in hair...
[Edited on 1-10-2004 by miamicanes]
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miamicanes
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OK, next question...
if I neutralize it using tin and HCl as described on page 344 of "Destruction of Hazardous Chemicals in the Laboratory", how likely is Dade
County's household hazardous waste collection center to refuse to accept it (they officially refuse radioactive, explosive, and infectious
waste)? According to the book, the fully-reacted tin renders it non-explosive (but still highly hazardous). I'm guessing that this falls into a
gray area... technically acceptable, but way outside the realm of what they actually expect people to show up with. Somehow, I suspect that if I took
it to them in a glass jar labeled 'neutralized picric acid', the lady behind the counter would probably blanche and ask me to very, very
carefully take it somewhere else...
As it stands, I can't find a single hazardous waste disposal company in Miami that actually has a web site (a bunch listed in various
directories, but only phone numbers), and miamidade's own web site says absolutely nothing about where to dispose of waste that they themselves
won't accept. Sigh....
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Dodoman
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Sounds like you'll have too much trouble disposing TNP. Then why not bury and detonate it? Looks so much easier to me.
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miamicanes
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Uh, aside from being massively illegal, wouldn't that be incredibly dangerous as well? From what I've read, it seems like picric acid reacts
with just about everything except glass, including limestone and iron. Florida "soil" is about 80% limestone, but it's the iron
I'm particularly worried about... there's lots of it in the water sprayed on the grass daily by the sprklers' well water.
Is there any reasonable dilution level at which picric acid can safely be stored in (nalgene?) plastic bottles?
How much picric acid is actually going to get produced by reacting enough indigotin and 70%w/v nitric acid to yield about 25g of Isatin, anyway?
I've been scouring the net all afternoon, but I still haven't managed to find it expressed as a properly balanced reaction that includes
atmospheric oxygen on the left (likely) and whatever gets emitted as smoke on the right.
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