Sciencemadness Discussion Board

Disposal of solvents

fdnjj6 - 30-7-2020 at 18:30

How do you dispose of flammable and toxic solvents? Mainly acetone, methanol, toluene, and chloroform?

I'd say you could evaporate them away or even boil them off but the issue for me is that I don't have a fan to push away the fumes as I watch it to make sure nothing goes wrong. I do work outside but even when simply handling a mix of toluene, acetone, and methanol, my throat has become a bit dry and feeling slightly irritated. I ended up wearing a OV respirator half way through which obviously filtered the vapors form that point on. The problem is I don't want to waste filters for solvents and I also look like I am working in a meth lab every time I do that so I'd rather just have a fan safely distribute the vapors.

How are those disposed of? Does anyone have recommendations for fans? Since I'm working with flammable stuff, the fan can't be one that produces sparks in the motor since I'd risk an explosion.

Also does anyone know if irritation is actually bad? I have had slight irritation in my throat from some experiments even though I was outside. Does irritation every once in a while cause any negative health effects?

fdnjj6 - 30-7-2020 at 18:32

I would like to get something like this but I don't know if the motor produces sparks. Would this be safe to use?

https://www.google.com/shopping/product/14687230848002640978...

Syn the Sizer - 30-7-2020 at 20:20

I would recycle the toluene by distillation. As for acetone and methanol, some might suggest recycling those too, but both reagents are cheap OTC so I don't, well with acetone if I just used it to dry glassware I do save it for other uses in a "wet acetone" container, unless a bit of water in the acetone is an issue for what I am doing.

To dispose of them you could just leave them in a well ventilated area and let them evaporate, and place any solids left over in a waste container. Depending what is dissolved in the methanol it can go down the drain with lots of water, same as small amounts of acetone.

Another option which I do with the majority of my waste is boil it down on a hotplate, or if non-volatile, a gas burner, never to dry of course to protect my glassware, I let it cool pour of the supernatant, collect the solid in a properly labeled waste container.

As for chloroform, I am not too sure, from my understanding it is a persistent aquatic toxin but I have never used it.

fdnjj6 - 30-7-2020 at 20:28

Good points made. Yea the methanol and acetone solvents are really not worth for me to recycle. I get it cheap and don't use much anyway. Since chloroform is produced in nature, boiling some off every once in a while shouldn't hurt the environment. I will try to recycle as much as I can though since I don't want to keep having to make more.

Also how do you deal with the fumes?

I really want to get a cheap ass fan from Walmart but I am scared that a spark from it could ignite everything. Then again since it's outside and the fan should be blowing away vapors, I don't really think the chance of vapors building up to a concentration high enough to ignite is even possible. This will vary from chemical to chemical obviously but I think there is a bigger risk of me having the fan just fail and shoot sparks everywhere. A fire isn't a huge deal since I have a fire extinguisher right at hand but I'd rather not risk risk it.

Also if the fan catches my reaction on fire and I destroy the expensive glassware using the fire extinguisher, that would really really suck. So I want to avoid fire as much as possible. While I feel like the set up I'd have with the cheap fan wouldn't be perfect, I can't help but think that the chance of fire from the fan is very low if not negligible.

What are your thouhgts?

Syn the Sizer - 30-7-2020 at 20:53

With acetone and methanol, if you are outside I wouldn't even worry about vapours. Just don't stand over top of the beaker you are boiling it in and don't stand down wind and as long as you are using a hotplate and not flame, and no flame source is within 3m you should be fine. The vapours will dissipate quickly, specially if there is a small breeze.

For toluene, if your condenser is efficient enough which should be fairly easy with a bp of 110°C, you shouldn't really get an vapours.

You make a good point about chloroform, letting it evaporate should be fine, but recycling saves the hassle of making more. To be honest even vapours from chloroform shouldn't be much of an issue outside as long as you follow same safety precautions as acetone and methanol.

[Edited on 31-7-2020 by Syn the Sizer]

Sigmatropic - 30-7-2020 at 21:24

Burning would be better, except for chloroform containing waste, disposing as flammable chemical waste best. What kind of volumes are we talking about?

Syn the Sizer - 30-7-2020 at 22:00

If you have a place to burn chemical that works good. Letting acetone and methanol evaporate in your backyard is legal but in most cities burning barrels are illegal, and you don't want to burn chemicals in your food fire pit.

Ultimately I find it easier to let them evaporate in a ventilated area rather than deal with flames. But I also only have small quantities. Most methanol I have used I just put down the sink with water like we did with methanol/ethanol/isopropanol in class unless it contains something hazardous. Acetone evaporates so quickly I often don't even need to worry about the volumes I use.

fdnjj6 - 30-7-2020 at 22:10

Okay good point. What about building up high concentrations and having it reach a source of ignition? Here the weather is super dodgy. It can be super windy one day and then out of nowhere it's nice and calm. I have seen gasoline form a large vapor cloud around a camp fire. It reached an ignition source and went up in flames. I am afraid of that happening since it is a very real possibility.

I'm very confident that my condensers can handle toluene but I'm not sure how many fumes would still make it through.

Slightly off topic but I haven't been getting much advice on this part. One of the issues I've also had that made me want to get a fan is that I seem to be pretty sensitive to vapors. I got a dry/slight sore throat just from handling a chilled solution of acetone, methanol, and toluene for a little while (less than 30 min). I was already dodging vapors as best as I could. I ended up putting on a respirator with OV filter. This was on a very calm day.

Also I would have a pretty good use for a fan since the vapors tend to change direction a lot with wind. Not only that but I am getting ready to perform some multi step organic synthesis which will have various fumes such as ammonia, acetic acid, nitric acid, NO2, etc. So I still want to get a fan to help out with that especially considering that I seem to be pretty sensitive to chemicals. Does anyone have any idea if a cheap $20 fan will work? Or is that an ignition source hazard due to the motor?

I would love to dispose of my flammable waste and all waste for that matter, through a proper company but no one here takes it. I might be able to get away with acetone and methanol but I honestly doubt they take from individuals and that is if I even manage to find a disposal site. Let alone the cost of disposal may be high too.

I want to refrain from flames as much as possible. The volumes vary. Right now I have proabably 750mL of acetone, methanol, and some toluene in water from the toluene extraction I just did. Most of my solvents end up in water in the end so I'd have to distill it out. After distillation we're probably talking 300mL max. Usually the solvent amount will vary but I likely won't be much above 300mL of solvent waste that needs disposing in the near future.

fdnjj6 - 30-7-2020 at 22:13

Also a fan would really help to evaporate solvents so I found another use for the fan haha.

I wasn't aware methanol could be diluted and poured down the drain.

Acetone does evaporate quickly. I'd have to distill the volatile flammable solvents out of the water that they are in. Most of my waste is always diluted in some water due to the synthesis or extraction methods I need to use.

Tsjerk - 31-7-2020 at 00:31

There might be people here completely terrified with the idea, but if we are talking about <liter, can't you just poor it down the drain? Or are you using a septic tank?

I wouldn't think twice about poring methanol/acetone/toluene/DCM through the drain in 100's ml quantities. By the time it gets to the waste processing plant it will be diluted beyond recognition.

fdnjj6 - 31-7-2020 at 00:39

Hmmmm I guess you have a point. The solvents would have to be diluted with water a lot so they don't ruin your piping. I'd say to not do that with toluene since it isn't miscible with water.

I just looked up some more info on it. It's a bad idea. The vapors will stay in the piping for a while and there have been reports of explosions from doing that. Also if you didn't wash the stuff down well enough, it can still eat the piping. Better to just let it evaporate outside I guess.

[Edited on 31-7-2020 by fdnjj6]

Tsjerk - 31-7-2020 at 00:55

I just run a minute or two of water, water comes cheap here. But if you have a place to evaporate, sure. I only have a balcony where my girlfriend also sits so we would smell it, inside I would have to let the ventilation run which makes quite a bit of noise.

Fyndium - 31-7-2020 at 01:00

I recycle all solvents I reasonably can. I collect different solvents in their own containers, like acetone, ether, methanol, toluene, etc and when I have those boring days or I'm just watching the stirrer do the magic I take the time to purify them. Acetone is maybe the easiest.

Acetone, alcohols and similar water miscible solvents can in my opinion be diluted and poured down the drain. Non-miscible or toxic solvents not so. I haven't yet thought how to dispose them, since if I have them on hand, I usually can recycle them. Water immiscible solvents can usually be washed with water a few times and then distilled pure.

On the other hand, small amounts don't really hurt. The water system is designed to handle thousands of tons of volume and many industrial settings drain their stuff in there as well, not including any seriously hazardous stuff, but like washing waters and so on.

The bad guys getting rid of evidence usually dump their junk in ground at some remote location. Please don't do that.

Syn the Sizer - 31-7-2020 at 07:47

Most solvents I agree but I get 4L of methanol for 10$ and 4L od acetone for 30$ so to be honest, I find those 2 plus things like isopropanol which I also get 4L for 30$ are just as easy to but considering their environmental hazard is minimal. But if those reagents are hard to come by in your area of course recycling is useful.

Though thinking about it, I really should recycle more acetone than I do, as you said it is so easy, you could almost distill it with a concave mirror on a hot day.

monolithic - 31-7-2020 at 08:04

The fan you linked has a shaded pole motor (I have the exact fan.) It's an induction motor so there aren't any brushes to spark. The speed is controlled by resistors, I can't imagine it would spark. If you're doing this outside and just using the fan to increase airflow the chances of a spark-induced explosion are negligible.

macckone - 31-7-2020 at 08:43

Disposal of non-chlorinated solvents is either recycle or burn.
If you were to send it to a hazardous waste disposal company that is what they do.
The chlorinated solvents need to be burned with a special furnace to avoid dioxin, PCBs and other poly-chlorinated compounds that are carcinogenic and toxic.
According to Hazardous Laboratory Chemical Disposal Guide by Armour, DCM can be mixed with flammable solvents and burned.
As for ventilation, using carbon filters on the exhaust fan is recommended.
Thanks to the burgeoning marijuana industry, good fans with filters are now really cheap.
Ideally, the fans are non-sparking. Most are shaded pole so work with voltage controllers and don't spark.
Additionally many fans used for ventilation are epoxy coated due to the high levels of moisture they deal with so are somewhat acid resistant as well as fairly solvent resistant.

Syn the Sizer - 31-7-2020 at 10:17

Yes, I understand that a waste management plant will burn waste. But as I said most people, specially in cities nave no place to burn their waste. I know if I was caught with a burning barrel in my city I would be fine hugely. I will not burn chemicals in my food fire pit since I do not need any residues on my food surfaces. Plus there are several times in my city that we have fire bans and even food pits are illegal.

On top of that, more and more cities are moving to 0 fire pits in your yard because people complain of the smoke, if you want a fire go camping, this I think that is BS. I have even heard stories of neighbourhoods where a smoking BBQ can get you a fine. For the average hobbyist burning is not possible. Though I do agree a superior method of disposal.

I do send my waste soaked paper and paper towel to my fathers to burn in his barrel though. Depending what it is soaked with I burn it for fun.

monolithic - 31-7-2020 at 10:37

If you have a car you can clean up the methanol and mix it with water and blue dye. Free windshield washer fluid.

karlos³ - 31-7-2020 at 10:38

You can redistill especially toluene and put it in your car.
Very high octane number, that stuff is good!

The other stuff I redistill too.
Depending on where they stem from, they are quite often reusable for different purposes.

macckone - 31-7-2020 at 11:55

If you can't burn it the solution is pretty evident, recycle it or pay someone to haul it off.

Syn the Sizer - 31-7-2020 at 12:39

Or if it is acetone and methanol which are not environmental hazards just let them evaporate. How many people in this forum burn all of their waste, and take what they can't to a recycling depot.

Or like we do in class put short chain alcohols down the sink with lots of water. Why waste money taking shit like acetone and methanol to a recycling plant. Just collect the solid residue and store that as waste if you say havre something dissolved in it, the vapours from the solvents are not the issue.

If YouTubers and the articles we read of peoples labs getting cleaned out after they pass are any example, most hobby chemists store their waste forever in their house, some poorly labeled so hazmat has to get involved.

So my opinion the methanol and acetone evaporating is screw all. Hell 10s of 1000s of litres get spilled industrially yearly and there is no concern.

Now environmental hazards yes dispose of properly.

Of course fdnjj6 should also check the laws in his region to see what is the legal route. If evaporation of solvents like methanol and acetone is illegal then of course recycle.

Edit:

Though as I said myself, I am considering recycling my acetone just because it is a little more pricy. But at 10$ for 4L jug of methanol, I couldn't bothered.

[Edited on 31-7-2020 by Syn the Sizer]

fdnjj6 - 31-7-2020 at 14:17

Thank you everyone! The info I got is really good and helped tremendously. I'll get that fan from Wally mart then since I still want to expose myself to the absolute minimum amount of any vapors. It's cheap anyway and I might as well. I already went on a small spending spree to do some upgrades on my lab. So $20 extra isn't really bad especially considering that it'll help me expose myself less to hazardous vapors. Not being exposed to stuff is kinda priceless anyway so $20 is a bargain.

RogueRose - 31-7-2020 at 16:24

Quote: Originally posted by fdnjj6  
Good points made. Yea the methanol and acetone solvents are really not worth for me to recycle. I get it cheap and don't use much anyway. Since chloroform is produced in nature, boiling some off every once in a while shouldn't hurt the environment. I will try to recycle as much as I can though since I don't want to keep having to make more.

Also how do you deal with the fumes?

I really want to get a cheap ass fan from Walmart but I am scared that a spark from it could ignite everything. Then again since it's outside and the fan should be blowing away vapors, I don't really think the chance of vapors building up to a concentration high enough to ignite is even possible. This will vary from chemical to chemical obviously but I think there is a bigger risk of me having the fan just fail and shoot sparks everywhere. A fire isn't a huge deal since I have a fire extinguisher right at hand but I'd rather not risk risk it.

Also if the fan catches my reaction on fire and I destroy the expensive glassware using the fire extinguisher, that would really really suck. So I want to avoid fire as much as possible. While I feel like the set up I'd have with the cheap fan wouldn't be perfect, I can't help but think that the chance of fire from the fan is very low if not negligible.

What are your thouhgts?


Get a 120 or 140mm computer fan(s) and use those. They use BLDC motors so no sparks possible.

BromicAcid - 31-7-2020 at 17:03

Collect and bulk up over the course of the year. Hand over for your annual disposal days or the like. Wherever I've lived there's been some sort of 'clean sweep' that they do once a year where you bring in hazardous waste.

zed - 10-8-2020 at 03:09

Burn Barrel? Yeah, folks wouldn't like that. But, if you poured your solvents on charcoal, then lite it.

Well that would just look like the prelude to a barbecue. Might actually be the prelude to a barbecue. Do you have a Barby? How much volume are we talking about.

Monoamine - 11-7-2021 at 11:39

Usually the local dump will take organic solvents. After all, they also take gasoline etc... It also helps to keep a log of all the organic waste you accumulated.

Monoamine - 8-8-2021 at 10:32

I collect my organic waste in a gasoline can, and keep a log book so I know what I put in there.
I then just bring it the local waste collection where they luckily take it. But I'm guessing any place that collects gasoline and paint thinner etc... should take it.

But if you have enough space then burning it in a small barrel may be fastests.

By the way: For more toxic reagents such as chromium compounds (reduced to the (iV) oxidation state what is the best way to dispose of it?

macckone - 8-8-2021 at 12:34

chromium (III) oxide is relatively inert if it is calcined in an oxygen free atmosphere.
In that state it can be disposed of as non-toxic waste.

This only applies to the calcined chromium (III) oxide.

Ideally, you would recycle the chromium.

Other substances have to be treated differently.

Example:
Mercury is considered non-toxic in the sulfide form.
Barium is safe in the sulfate form.
Beryllium is safe as the aluminosilicate (beryl - hard and insoluble)
Selenium Sulfide can literally be poured down the drain mixed with a surfactant.

Every element has it's own peculiarities and preferred form for disposal.

karlos³ - 8-8-2021 at 18:43

Quote: Originally posted by Monoamine  
I collect my organic waste in a gasoline can, and keep a log book so I know what I put in there.
I then just bring it the local waste collection where they luckily take it. But I'm guessing any place that collects gasoline and paint thinner etc... should take it.

But if you have enough space then burning it in a small barrel may be fastests.

All in the same can?
I'm just thinking, there might be oxidising and reducing residues in there... might be better to have two of those on hand ideally.

Well, Shulgin had a walled pit in his garden, where he burned organic residues... which apparently, was the recommend method within states laws, in california or what :o
You can see said pit even in that one documentation, when they busted him after he violated his DEA license terms.
They even do some field tests on said pit if my memory serves right, and they are apparently satisfied with the results, so it must be quite lax... compared to european laws at least.

As for chromium(III) compounds, I add iron powder to the liquid wastes to reduce it to the relatively less toxic (VI) state.