Chemistry, as a field, acknowledges three types of alcohol: isopropyl, methyl, and ethyl alcohol. Each of these types of alcohol has distinct properties, so it is important for scientists — and humans in general — to distinguish which type of alcohol is which, if only for safety reasons. Each kind of alcohol also has specific applications in personal and industrial environments. While no form of alcohol is good for humans, per se, the species has a long history of using ethyl alcohol as a recreational drug.
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There are three main types of alcohol: isopropyl, methyl, and ethyl. All are toxic, and only ethyl, or grain, alcohol can be consumed by humans, but the others find use as sterilizing agents, or as fuels.
Isopropyl alcohol — also called isopropanol or 2-propanol or rubbing alcohol, more commonly — finds use among physicians, who rub the poisonous substance onto surfaces, tools and human bodies for its cooling and disinfecting properties. Produced by combining water and propylene, rubbing alcohol works well for sterilization. Its high evaporation rate makes it a common choice for cleaning electronics, although it is found in everyday cleaning products, as well. Isopropyl alcohol also is found in cosmetics, including lotions. The chemical formula for this type of alcohol is C3H8O. Often, isopropyl alcohol — along with other more dangerous types of alcohol — products contain bittering agents that dissuade people from drinking it.
Methyl alcohol, also called methanol and wood alcohol, primarily finds use as an industrial solvent. For example, paint remover and photocopier developers make use of it. People with experience and know-how also use methyl alcohol to make other chemicals. Formaldehyde forms as a byproduct of degrading methanol — some industries use this byproduct to make everything from plastics to explosives. It also works to fuel internal combustion engines and keep other fuels from freezing, thanks to its high freezing point, -143.68 degrees Fahrenheit.
People — mostly adults — consume ethyl alcohol, sometimes called grain alcohol, in beverages. People usually imbibe ethyl alcohol in a diluted concentration — the level of the concentration is known as the proof of the alcoholic beverage — to improve its taste. Ethyl alcohol is known for its ability to alter mood and behavior. Brewers and distillers usually make it from grains or other pieces of plant matter with high sugar contents. The liver usually is able to filter ethyl alcohol from the human body, but ethyl alcohol still is toxic when consumed faster than the liver can metabolize it. Like methyl alcohol, ethyl alcohol also has uses as an industrial solvent and as a fuel additive.