Ethanol

Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula CH3CH2OH. It is an alcohol, with its formula also written as C2H5OH, C2H6O, or EtOH, where Et is the pseudoelement symbol for ethyl. Ethanol is a volatile, flammable, colorless liquid with a pungent taste. As a central nervous system (CNS) depressant, it is the active ingredient in alcoholic beverages, and the second most consumed drug globally behind caffeine.

Ethanol is naturally produced by the fermentation process of sugars by yeasts or via petrochemical processes such as ethylene hydration. Historically it was used as a general anesthetic, and has modern medical applications as an antiseptic, disinfectant, solvent for some medications, and antidote for methanol poisoning and ethylene glycol poisoning. It is used as a chemical solvent and in the synthesis of organic compounds, and as a fuel source for lamps, stoves, and internal combustion engines. Ethanol also can be dehydrated to make ethylene, an important chemical feedstock. As of 2024, world production of ethanol fuel was 120 gigaliters (3.2×1010 U.S. gallons), coming mostly from the U.S. (51%) and Brazil (30%).

The term "ethanol", originates from the ethyl group coined in 1834 and was officially adopted in 1892, while "alcohol"—now referring broadly to similar compounds—originally described a powdered cosmetic and only later came to mean ethanol specifically. Ethanol occurs naturally as a byproduct of yeast metabolism in environments like overripe fruit and palm blossoms, during plant germination under anaerobic conditions, in interstellar space, in human breath, and in rare cases, is produced internally due to auto-brewery syndrome.