ethanol alchohol is one of the additives put into Mogas for a number of reasons. It is not permitted for it to be put into Avgas. There is an article from the CAA that compares Avagas and Mogas and identifies the differences in the Mogas "cocktail" which forms part of the reason for the restrictions in the use of Mogas and the reason it is not allowed for Public Transport use.
I will find the .pdf link and post it.