Denatured alcohol is ethyl alcohol with toxic or bad tasting additives that make it unsuitable for consumption. The chemical formula of ethyl is C2H6O and the formula for isopropyl alcohol is C3H8O. The most common additive to denatured alcohol is 5 to 10 percent methanol.
Denatured alcohol is most often used in the concrete industry as a final wipe before laying down an epoxy coating on concrete or in between coats of epoxy, polyurethanes or polyaspartics. Because it evaporates quickly there is no lag time between cleaning and applying the coating.