Sciencemadness Discussion Board - fenton's reagent and picric acid liquid disposal

fenton's reagent and picric acid liquid disposal

ManyInterests - 26-9-2022 at 12:17

I'm prepping up to make some picric acid (which I also hope to turn into ammonium picrate) and one question that has been on my mind for a long time is this: once I filter out all the picric acid. There will be some leftover liquid with some picric acid still in there. Disposing of the stuff down the drain is obviously not a good idea. I do think most piping in my area is PVC (thus not likely to form any explosive salts) but I do want to neutralize it just to be absolutely sure everything is OK.

The alternative would obviously be to bottle the stuff up and toss it in the trash, but I want to know how to render it safe even if I decide to do that.

I know picric acid can be neutralized with fenton's reagent. I have a bottle of ferric chloride to use as an iron source, as well as plenty of homemade 30+% H2O2 ready, but I am wondering proportions of both to make a good fenton's reagent, add it to the left over liquid and wait a few hours for everything to react before pouring down the drain.

It's actually the biggest thing on my mind before I continue with this, so I really need some instruction on the chemistry of this (as well as some hard numbers) before I do this. I'd greatly appreciate it.

Herr Haber - 26-9-2022 at 13:07

NaOH all the way.
I wouldnt think twice about sodium picrate in the drain.

But I'd do something useful with that picric acid and bleach if I were you. You never know when you might need a... fungicide

Good to see you broadening your horizons.

ManyInterests - 26-9-2022 at 13:19

Hold up, putting in sodium hydroxide in the liquid will render it safe?

How long does the reaction time last? NaOH is inexpensive and I have no problem using an excess of NaOH crystals into what is left and calling it a day.

Also what about bleach? Is adding it safe and that can be flushed down the toilet after mixing it and letting it sit for a while?

Herr Haber - 26-9-2022 at 19:51

Simple acid base neutralization.
Sodium picrate seems to be the less hazardous that's why I suggested NaOH.

Bleach was a bad joke. That's an alternate path to trichloronitromethane. It is a potent fungicide among other things.

I still suggest you keep a small amount for further experiments, wet if it makes you feel better.
There are interesting experiments to make with picric acid. Having fun with the crystal shape, DDNP, experiments of triboluminescence with sugar.
There are lab suppliers selling it in 5kg quantities for histology. I'm pretty sure you can find a few interesting uses.

And it's a dye. It will happily remind you of it if you splash some on clothe but even glassware can get a yellow / greenish tint.

ManyInterests - 26-9-2022 at 20:13

Yes. Picric acid is fascinating. Both in the historic context and in the chemical context.

DDNP is something I am also interested in making some day. But I won't be using it to make blasting caps, since I have NHN that is more powerful and safer for that purpose.

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And it's a dye. It will happily remind you of it if you splash some on clothe but even glassware can get a yellow / greenish tint.

It can taint glassware? I didn't know that. That is interesting. I am aware that picric acid was used as a dye for a good long time. TNT also started out as a dye... before they realized that it is a high explosive as well.

It's actually kinda amazing how so many HE were discovered originally for entirely different purposes.

Elemental Phosphorus - 10-10-2022 at 10:00

When I made picric acid a few times I disposed of the picric acid-contaminated water by pouring it onto wood ash from the fireplace and disposing of it in the trash. It would always bubble a bit, maybe carbonates in the ash. Perhaps if you don't have any wood ash some cement powder would do just as well. But at any rate I don't think picric acid is an overly hazardous chemical, neutralizing it with a base and pouring it down the drain is probably fine.

Amos - 10-10-2022 at 11:57

I'd just keep on evaporating the leftover liquid; you stand to get a lot more picric acid that way, often in gorgeous crystal shapes. By the end you'll have very little waste to deal with.

ManyInterests - 12-11-2022 at 23:35

I need to mention this, that mentioning bleach and picric acid to me was the deadliest joke I ever heard. I did do it several times but in the previous times there was very little picric acid in my stuff (due to the failure in making it) and I nearly killed myself with the stuff. I didn't realize that trichloronitromethane was used as a poison gas during WW1 in addition to being highly toxic and carcinogenic.

I need a cheaper source of sodium hydroxide because I am actually succeeding in making picric acid now and this stuff is REALLY deadly.

The only dangers I ever had in this hobby were gasses and most of them were in the disposal of some stuff. Picric acid waste disposal is being DEADLY. I need to get a handle on this before I die of cancer before I hit 50 or die much sooner.

Edit:

https://www.answers.com/earth-science/What_happens_when_picr...

Is this correct? Is sodium bicarbonate sufficient to bust up picric acid?

Edit2: I just remembered the U2U I had with Herr Haber. You can use sodium bicarbonate and just flushing it down the toilet is also acceptable, I will do that. I really can't inhale any more cancer gasses.

[Edited on 13-11-2022 by ManyInterests]

[Edited on 13-11-2022 by ManyInterests]

Herr Haber - 13-11-2022 at 11:58

Err... man. I feel awful because I honestly thought you'd see it was a joke: I wrote it ! Or at the very least research the compound name !
That is not a way to "dispose of" PA but to use it as a reagent. Now I undersand your U22. I was wondering where you were getting the chlorine from !
Yeah, NahCO3 and NaOH are both ok and will produce the same sodium picrate waste.

And, though I woulnt use the mother liquor or first water from recrystallisation as Amos suggests he is right about the gorgeous crystal shapes you can get. Star clusters, "combs" with 5 cm needles, cubic crystals...
There are a lot of very informative threads on PA here on SM on how to "tweak" your procedure to get such or such result.
The journey is definitely as interesting as the destination if not more.

ManyInterests - 13-11-2022 at 12:45

I really didn't see the joke. I also did ask others and they seemed to think it was OK. I'm autistic and sometimes a little impulsive (not a good thing to have with chemistry!) I also had no idea that it was going to be that deadly. I saw you mentioned a fungicide, so I thought 'OK that's no so bad. I can flush that down the toilet. But I had no idea that trichloronitromethane was also used as a powerful poison gas during WW1. It was orders of magnitude over chlorine in danger. Like holy shit. I now have Battle of Ypres flashbacks when this happens.

Like please don't make statements like that when I'm asking questions. I do have a tendency of doing what people recommend to the T.

Also it's good that sodium bicarbonate also works. I used up too much of my sodium hydroxide, and while you do need less sodium hydroxide, it is much more expensive than bicarbonate. I spend 9$ per 500 grams of hydroxide but 1$ for the same of bicarbonate. I can just buy two kilos of bicarbonate and dump it all for neutralization.

I CANNOT keep having these things happen. I don't want to end up being on a forum post of 'SM members who died doing X' with the content 'you totally can just flush this shit down the toilet and you don't need to add stuff to it that'll result in toxic gases being emitted that'll kill you even in a well-ventilated area'

Quote:

And, though I woulnt use the mother liquor or first water from recrystallisation as Amos suggests he is right about the gorgeous crystal shapes you can get. Star clusters, "combs" with 5 cm needles, cubic crystals...
There are a lot of very informative threads on PA here on SM on how to "tweak" your procedure to get such or such result.
The journey is definitely as interesting as the destination if not more.

Yeah I learned a lot. Like my last nitration yesterday (I still need to recrystalize everything) was a great success and it went off without a hitch. No runaways, no bad reactions, the makeshift fumehood I made also protected me well against all the NO2 gasses released during adding the nitrate salt. My product looks so different than that the last two attempts.

Maybe I will boil down the water with the picric acid in it later and see if I can pull more from it. But so far my main problems and dangers from chemistry have never been nitrations or the actual production of the stuff, it was always the disposal of byproducts.

Like my hydrazine sulfate synth. I've made hydrazine sulfate many times and never had any issues with hydrazine fumes. But it was me trying to dispose of the left over liquid that caused similar problems in the past. Then Mineman and Laboratory of Liptakov just admonished me and said 'flush the thing down the toilet! You think this stuff is harmful to poop?' So from then on that's what I did. It resulted in me being able to make a good deal of high-quality hydrazine sulfate with no nasty disposal issues. My Nicke-Hydrazine-Nitrate (NHN) synths from then on also went without a hitch.

I wish the disposal section on the wiki always says that baking soda can work. Good ol' baking soda! My best friend in the whole universe right now!

[Edited on 13-11-2022 by ManyInterests]

Herr Haber - 14-11-2022 at 22:34

Quote: Originally posted by ManyInterests

I'm autistic and sometimes a little impulsive (not a good thing to have with chemistry!)

Like please don't make statements like that when I'm asking questions. I do have a tendency of doing what people recommend to the T.

This is the reason I feel so bad for that "joke". I should have known better.
I remember you saying that in another post. I've worked with neuro-atypics. I trained a young colleague with Asperger / ADHD and this incident reminds me of one with him. He was cheerfully going to do what I had told him *not* to do. But that was fun at least and I learned to communicate with him.
I will be careful how I word things from now on.

Quote: Originally posted by ManyInterests

If you're slow in your nitrate / acid addition and raise the temperature super slowly over a long period of time you should only get a bit of NOx.
I've often wondered if crude picric acid made from different nitrate salts would have a different aspect.

Quote: Originally posted by ManyInterests

Maybe I will boil down the water with the picric acid in it later and see if I can pull more from it. But so far my main problems and dangers from chemistry have never been nitrations or the actual production of the stuff, it was always the disposal of byproducts.
[Edited on 13-11-2022 by ManyInterests]

You will pull more picric acid from the mother liquor, no doubt about it.
Boil some water down, put in fridge, filter, repeat...
What you cannot do is extract it all since this mother liquor contains H2SO4 and picric acid is soluble in it. I think above 70% H2SO4 / H2O you end up having more picric acid dissolved in H2SO4 than in the water. Not sure about that 70% number though. This is why you add water at the end of the third nitration. Anyway: those second batch crystals will have a lot of H2SO4 in them so you're now having the same problem with your second impure (since there was more H2SO4) batch that you had with your purer first batch.
Dont mix it with your main product. You'll see it has a slightly different color and the crystals are different even if you properly wash / recrystalize them several times.
It's worth doing it for educational purposes and to learn how to dispose of your waste. Waste management is part of the hobby that I dont see as a burden. You get to learn more stuff !

ManyInterests - 15-11-2022 at 03:27

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Thanks for noting that. Hopefully there will be more incidents. I am managing NO2 gasses quite well, as I did in my more recent picric acid synth.

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One thing I should have done is recalibrate my thermoprobe on my mantle, since it gave me REALLY bad temperature reading when I was processing the ASA in sulfuric acid. Thankfully I have a 2nd electric thermometer that helped. But to give you an idea on the temperature difference, my mantle gave a reading of only 82C while my electric thermometer gave me 152C. I depended on my other thermometer throughout all this.

And I did notice that there is a slight difference between sodium nitrate and potassium nitrate. I am not exactly sure what is the real difference so far, but it is just a gut feeling.

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Yeah, my 2nd batch of picric acid that I have been processing all night (so far) involved me crashing it in far excess of water that was needed. I ended up with over 1600ml of water that was filtered through! So what I did was add the picric acid in my coffee filters back to the mix, and added another 400ml of distilled water and I am boiling it down again. I am almost at 400ml and I will crash it.

I am actually going to go on a vacation so I will just cover it and leave it until I return. I'll be back in a week or so and I recommence the process. I can do some basic filteration and add more distilled water to both mixtures.

ManyInterests - 16-11-2022 at 00:04

Well I used sodium bicarbonate to dispose of the final waste from the remaining bits of mother liquor of my 2nd batch it took a bit of time to react, but the reaction from picric acid to sodium picrate (the red stuff) and it was quite the sight! But it emitted no dangerous gasses and was quite safe. I am very proud of myself. Very little actual picric acid made it into my drains!

And yes, adding water to the H2SO4 BEFORE crashing it into ice/ice cold water is essential. I learned that in 2nd synth. From here on out when I make picric acid I'll do that step. I didn't realize that it was quite specifically required. But now that I know, I'll do it. It'll save a LOT of time in purifying and recrystalizing. But it was a good experience.