TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The composition further comprises: water (less than 1 vol.%); at least one organic impurity including acetaldehyde (less than 10 wppm), diethyl acetal (less than 10 wppm), n-propanol (95-270 wppm), ethyl acetate, acetic acid, butanol, 2-butanol and/or isobutanol, where the ethanol composition comprises less than 1 wt.% of the organic impurities, and less than 300 wppm of 4-5C alcohols; and at least one additional alcohol that is not in situ-formed alcohol. Preferred Components: The fuel denaturant is natural gasoline, gasoline blendstocks or unleaded gasoline. In the composition the weight ratio of isopropanol to water in the ethanol composition is 1:80-1:1000. The weight ratio of isopropanol to n-propanol is at least 0.5:1 or at least 1:1. The ethanol composition: is not fermentation derived; and is free of benzene, methanol, 5C alcohols and heavy metals. The ethanol composition optionally comprises chlorine (less than 40 wppm), copper (less than 10 wppm, or less than 0.5 (preferably less than 0.1) mg/kg), sulfur (less than 50 wppm), sulfates (less than 10 wppm), phosphorus (less than 2 mg/l), and lead (less than 15, preferably less than 5 mg/l). The ethanol composition comprises: manganese (less than 10, preferably less than 1 mg/l); less than 8 (preferably less than 5) mg/kg of a combination of sodium and potassium; less than 10 (preferably less than 5) mg/kg of a combination of calcium and magnesium; less than 60 (preferably less than 25) mg/kg of a combination of aluminum and silicon; less than 150 (preferably less than 100) mg/kg of sodium; less than 400 (preferably less than 350) mg/kg of vanadium; less than 50 (preferably less than 30) mg/kg of calcium; less than 25 (preferably less than 15) mg/kg of zinc; less than 350 wppm alcohols other than ethanol, where the ethanol composition has a pH of 6-9.5, has a total acidity (as acetic acid) of less than 0.01 wppm, is synthesized via acetic acid hydrogenation and purification, and the denatured ethanol composition, as synthesized, comprises substantially no non-in situ denaturants. The acetic acid is formed from methanol and carbon monoxide, where each of the methanol, carbon monoxide, and hydrogen for the hydrogenating step is derived from syngas, and the syngas is derived from a carbon source including natural gas, oil, petroleum, coal and/or biomass. The composition comprises less than 1 wt. % of at least two other alcohols (preferably isopropanol and n-propanol) other than ethanol, where the other alcohols are in situ-formed alcohols. The denatured fuel ethanol composition comprises ethanol composition containing at least 95 wt.% of ethanol, and at least 95 (preferably less than 1000) wppm isopropanol, and n-propanol (less than 270 wppm). EXAMPLE - Typical denatured fuel ethanol composition comprised of: ethanol (92.7 wt.%); water (7.4 wt.%); acetic acid (14 wppm); ethyl acetate (70 wppm); isopropanol (110 wppm); n-propanol (160 wppm); 4C alcohols (21 wppm); acetaldehyde (5 wppm); alcohol with 2 or more carbons (291 wppm); and diethyl acetal (1 wppm).