strontiumred - 25-3-2011 at 08:20
Hi,
I'm trying to find out more about the oxidation products when when alkaline pyrogallol is oxidized by air.
This reference suggests the purple colour is caused by a benzotropolone called "purpurogallin" with other products forming later.
http://www.swisseduc.ch/chemie/orderchaos/reaktionen/pyrogal...
Here is a rather shaky video I made of the reaction.
http://www.youtube.com/watch?v=If9goM5wci4
It would be nice if the purple colour was purpurogallin as I have never made or come across a seven membered ring in my (mainly inorganic) experience.