After being lucky enough to live with roommates who were cool with reducing naphtha pulls with a fan, my grandson Morty will be moving into an apartment where it may be unwise to evaporate naphtha in the open air. Although it does not give as strong of a smell as many other solvents, it is still faintly noticeable at times. It seems that solvent could be reduced by using a vacuum and a cold trap to catch the solvent. A length of tube would be secured in the lid of a baking dish. The other end would be fed through the lid of a mason jar, extending maybe halfway down. Another tube would be attached through another hole in the mason jar lid, but only extending a few inches below the rim in order to avoid sucking up any condensed solvent. At the other end of the second tube would be placed a vacuum source, either a handheld vacuum pump or a small diaphragm pump (45w?) in order to provide auction. The mason jar would be placed in a jar of ice in order to cool the evaporated solvent and cause it to condense in the jar. The baking dish lid is secured on a baking dish containing The combined naphtha pulls in order to create a small vacuum chamber. Does anyone have any experience with these techniques or know whether this would work or not? My grandson's aim is to reduce solvent and collect the excess in the jar for later use. Obviously he wouldn't want any spice dissolved in the naphtha to be carried over through the tubes or this would defeat the point of reducing at all. Any feedback would be greatly appreciated!

I once tried naptha to see how well it worked. it worked 'okay', it too, quite a lot of liquid so I can understand your concern. IIRC I think I used the topend of a vaccum dessicator and a recycling water aspirator to dispatch the fumes and recollect some solvent.

I didn't recover much, but it did deal with the odor.

perhaps a less smelly solvent would work?

Is purchasing a rotary evaporator out of the question?

-eg

Yes there is a lot of liquid! Even pulling with 50-60ml at a time will result with a combined volume of 300ml or more which my grandson Morty likes to reduce to around 50ml or so before precipitation. The vacuum dessicator and water aspirator setup seems like it would be a cost effective solution to this problem. Recovering solvent isn't the main concern, since naphtha is pretty cheap, so this method should work great! Do you know of any solvent which are less conspicuous than naphtha?

I wish I could buy my grandson that rotovap but he wouldn't use it nearly enough to make the investment worthwhile.

chloroform/dcm probably. I've alwaye loved the smell of chloro :3.

but more useful: you only need to use very little, and they are quite volatike and evaporate quickly.

Using a rotavap is glorious overkill in this case and diy vacuum setups are hard to construct and probably dangerous if any decent level of vacuum is actually attained. Did I mention that vacuum pumps are typically noisy?

All that is needed here is an improvised mini fume hood. You can conveniently build one from a cardboard box, some length of flexible tubing (eg. tumbler dryer vent tube), a computer cpu fan and a 12 volt wall wart and a patch of cloth to act as a dust filter on the inlet. Duct tape it all together and lead the tubing out of the window. The fan will displace more than enough air through the box to dilute the vapors adequately, so that no smells will be noticeable outside.

Don't forget to mount the fan on the outlet hole of the box, so that the box has a relative underpressure in it. If you push air into the box, any cracks or leaks in the construction will leak vapors back into the room.

I've left some naphtha to evaporate under my bed, and there were no smells. I put a CD jewel case on the opening, with a little bit of a gap for the vapour to escape. It took about a week or two to fully evap, but it was winter and not exactly well lit or ventilated. I also never close my window in my room, so that most definitely helped with the smell.

I got huge crystal formations using that method.

Ive wanted to acquire some DCM for a while now but I'd need some distillation equipment to ensure quality and a sep funnel to use it. I know it would save me a lot of work in that I would only need to do a couple pulls in order to catch all the magick. Chloroform might be a little easier to come by though.

Thanks pitubo! That sounds like a cheap and effective way to discretely accomplish what I need. I think I saw some instruction for a fume hood over a year ago on here before I even made an account but completely forgot about it until you just mentioned it.

I really like the idea of slowly evaporating over several weeks. I'm usually not in a hurry and don't mind waiting if it saves me the trouble of stinking up my place with naphtha for a few hours. I know that the slower the crystallization the larger and cleaner the crystals obtained. I'd probably just let it sit until it reduced to about 50ml or so, at which point a few crystals would likely have dropped out and then pop it in the freezer to precious the rest.

Thanks so much for the advice everyone!

I prefer freeze precip over slow evaps. The powdery crystals are a lot easier to vape than the large crystals. I also prefer to be less wasteful with reagents.

I've seen people saying slow evaps result in cleaner crystals, but I can't find the data on this fact. What does cleaner mean? I can't imagine that the evaporating solvent is taking anything with it. I've had a bit of residue with some evap yields, but it wasn't any "cleaner" than freeze precip.

To be straightforward, "discretion" is not my reason for suggesting this, safety is. Accumulating solvent vapors in living quarters is not a safe practice. An improvised simple fume hood solves most of the solvent vapor problem.

When I first saw your OP, it did make me think of the part of the attitude page stating that we should not give tips on 'stealth' teks. Please read the attitude page if you hadn't yet. IMHO even full members should re-read it every now and then.


That might have been this post? The forum search engine is really good. It often saves a lot of typing when you do not have to retype questions that have already been answered.


I'm not an expert on crystal growth, but I think that fast crystal growth can cause much more impurities getting included in and between crystals.

Ideally, a single crystal would grow evenly layer by layer, accumulating only one type of molecule. In practice, crystal growth is a stochastic process with a complex dynamic. Edges attract new growth much easier than faces, leading to uneven growth, possibly causing lattice defects. Many crystals, with dissimilar lattice orientations, can grow into each other, creating cavities filled with impurities. When a crystal grows very rapidly, impurities sticking to the crystal lattice are simply overgrown and encapsulated by the forming crystal. Very slow crystal growth mitigates some of these problem factors and leads to more perfect crystals with less defects and inclusions.

Bodhisatva, I explained earlier in this post that the idea was not to completely evaporate solvent but only to reduce the volume to increase spice saturation per ml of solvent before freeze precipitation. This causes the crystals to fall out of the solution much more easily.

Pitubo, I think you may have misinterpreted my grandson's intent. He did not wish to hide his activities from anyone with whom he shares living quarters, rather he seeks to avoid attracting the attention of law enforcement, which I'd imagine is a goal shared by the majority of Nexians unless they have the fortune of living somewhere that isn't ruled by a government bent on legislating and enforcing draconian drug laws. It is easy to imagine a random neighbor who isn't very chemistry savvy to mistake a small scale botanical extraction for a meth lab or something similarly dangerous. I know I'd be anxious and more than a little upset if I thought someone in my building was running a meth lab. I really do appreciate you looking out for my safety as I agree that it's not good for anyone to inhale naphtha in any quantity!

nah, some tubong, a pump, water aspiratorm and a 5 gallon bucket.