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Cake day: July 15th, 2023

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  • 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.



  • 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.


  • I worked on a similar (but competing) technology to this one for a few years. Depolymerization is absolutely the way forward for most polymer recycling.

    For most uses, manufacturers want plastic that’s colorless and has good physical properties. Melting down clear plastic can work, but it degrades the polymers in hard-to-control ways. And if there’s any pigment in the plastic, forget about it.

    If you break down polymers into their constituent monomers, you’ve turned a polymer process into a chemical process. Polymers are hard to work with. Chemicals are, comparatively, pretty easy. You can do a step or two to extract all the color and impurities, then re-polymerize the cleaned up material and get plastic that’s indistinguishable from brand new.

    If your depoly process is good, it can distinguish between different polymers, so you can recycle mixed waste streams. Ours was even pretty good at distinguishing nylon from PET, which I sorta doubt the zinc process will be. But hey, more competition in this space is gonna be good for the world.