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.
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.