Sciencemadness Discussion Board

Stripping IPA to dryness - peroxides?

horribilis - 27-10-2019 at 13:30

I have some reactions that are ideally run in IPA. The latter steps of the synthesis involve stripping all IPA under vacuum to yield an oily product. This would be done with a conventional distillation apparatus, under vacuum and on a warm water bath.

I realize that IPA "can" form explosive peroxides and I have read a few papers on this phenomena. Realistically speaking, what are the chances of this occurring if the 91-99% IPA is fresh and has been stored in the dark? I don't think there's a major risk of heat driving the peroxides to spontaneously explode. I also doubt the stir bar would give enough physical shock to initiative detonation, if peroxides even exist?

People have stripped IPA under vacuum, with or without a rotovap. And there have not been explosions left and right. So maybe I am being paranoid?

SWIM - 27-10-2019 at 15:28

They do have test indicator strips for organic peroxides.

I don't think there's much risk to what you're doing, but the strips could come in handy as insurance.

And they work for a wide range of peroxides. I may just buy a bottle myself to assuage my worries about some old ethers I have.

EDIT: A quick check on Ebay shows several ranges from 0-100 ppm on up to a 3% to 10% range strip that's for testing hydrogen peroxide, but works for most organoperoxides too.


[Edited on 27-10-2019 by SWIM]

horribilis - 27-10-2019 at 18:03

Quote: Originally posted by SWIM  
They do have test indicator strips for organic peroxides.

I don't think there's much risk to what you're doing, but the strips could come in handy as insurance.

And they work for a wide range of peroxides. I may just buy a bottle myself to assuage my worries about some old ethers I have.

EDIT: A quick check on Ebay shows several ranges from 0-100 ppm on up to a 3% to 10% range strip that's for testing hydrogen peroxide, but works for most organoperoxides too.


[Edited on 27-10-2019 by SWIM]


Thank you, I will definitely look into those test strips!