@EvilSOB
One thing is wrong in your idea
alcohol ( if we talk about ethanol the one you are drinking ) mixes with water.
alcohols in general doesn't mix with water with a chain lenght longer than 4 ( if i remember right so pentanol wouldn't mix with water.
A fluid which won't mix with water could belong to the group of Alkane ( sorry doesn't know the english term must be similiar )for example octan.

In general i believe a perpeetuum mobile is possible if it doesn't power something else or looses energy.

muffel