Isopropyl alcohol is a known peroxide former. 

Several years ago, a professor was having his students do a fractional distillation of IPA and toluene.  After several of the boiling flasks had exploded after the toluene was gone, he stopped the experiment.  And wrote to C&EN.  Michael Heylin the editor at the time replied that IPA has been known to be a peroxide former for many years.   ... Jim

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On Fri, Oct 3, 2025 at 3:08 PM Laurie Yoder <000022a100962bdc-dmarc-request**At_Symbol_Here**lists.princeton.edu> wrote:

I am doing a chemical hygiene independent study course with a student, and (mainly for educational purposes) we tested our 2-propanol in the stock room with peroxide test strips. There was an intense unmistakable color change, which seemed surprising given that the containers are less than 1 year old. My question is if others of you with more experience have gotten positive tests like this--can it really contain that much peroxide or is there some other interference happening with the test strips? 

• The brand is "WaterWorks", not expired.
• The strip was dipped in the 2-propanol, extra drips removed, then a drop of DI water was added to the strip.
• We also tried it in reverse-adding the water first, then dipping. Same result.
• Other organics tested in this way did not indicate any peroxides.

We don't distill the stuff so I'm not overly concerned, mainly curious. What's happening?

Laurie

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Laurie M. Yoder, PhD (she,her)
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Associate Professor of Chemistry and Chemical Hygiene OfficerFaculty Athletics RepresentativeEastern Mennonite University

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