Side project: Isopropyl distillation from resin printing rinsing
Side project: Isopropyl distillation from resin printing rinsing
Edit: Deleting this post. It's starting to get controversial, but that's OK. Not what I planned on, but whatevers.
You're viewing a single thread.
No no no no no.
I’m a chemist. Organic chemistry PhD, now a process chemist in the industry. I do this for a living. Do not distill isopropanol that’s been exposed to air for any meaningful length of time.
Isopropanol slowly reacts with oxygen in the air to generate peroxides that, when you concentrate them down, EXPLODE. Source. Sorry, not an open access journal. But please take my word for it.
Unless you have a way of confirming the peroxide levels in your isopropanol are near zero, do not concentrate it down by distillation. You’ll blow up your glassware, which will probably expose what you’re distilling to your heat source, which will generate a secondary fireball.
PLEASE do not do this.
Permanently Deleted
The issue with isopropanol peroxide formation is that exposing it to air – even when just using it, like when you’re cleaning parts – starts the process. The air in the head space of your containers is also enough to form them over time. You don’t necessarily need to see solids in the containers for it to be dangerous, since they’ll crystallize out as you concentrate the solution during distillation.
It’s also a numbers game. It probably won’t explode the first time you do it. But there’s a chance each time. Do it enough, and you’ll have an incident.
There are chemical reductants that can clear peroxides. For industrial scale isopropanol distillation, I’m not sure what they use. It may be that they just never distill down to the point that peroxides concentrate to a dangerous level.
If this were a closed loop cycle for the IPA, I could see an issue. Between normal losses using the IPA in my projects, disposing of fairly diluted concentrates while also replenishing the IPA with fresh stock doesn't seem like it would allow for for dangerous levels of peroxide buildup.
Testing the IPA is a good route to take though. If peroxides are coming across during distillation or if the dirty IPA contains measurable peroxides, that would be good data to have.
I am not above spending the cash to have an analysis done on the purity of my IPA either. It would be a hair expensive, but data is invaluable.
Sounds like fun! Got to go get a still though.
Please, don’t do this thing.