Sciencemadness Discussion Board

condensation product in old sample of methyl benzoate

DieForelle - 7-2-2017 at 11:52

was recently going to dispose of some 10 year old methyl benzoate, 500 ml. I noticed 3 flower-like crystals of some kind of condensation product in the bottom of the amber bottle. About the size of a small button mushroom cap. Immediately moved it outside and decanted most of the ester off into another container. Is it possible those are explosive peroxides? Seems more likely they are just byproduct of a slow hydrolysis...going back to benzoic acid. But I wanted to be sure.

Dr.Bob - 7-2-2017 at 13:34

I would guess benzoic acid, simple enough to test, let the crystals dry and take a mp. Not much likelihood of peroxides forming in a ester. I see those in old bottle of benzaldhyde often.