Methanol, << METH uh nohl or METH uh nol, >> is a type of alcohol used for many industrial purposes. It is also called methyl alcohol or wood alcohol. Methanol is a clear, colorless organic compound. It is flammable and highly poisonous. Drinking methanol, or inhaling its fumes for prolonged periods, can cause blindness or death. Methanol also can be absorbed through the skin.
Methanol’s chemical formula is CH3OH. It has a relative molecular mass of 32.04. A molecule’s relative molecular mass, sometimes called its molecular weight, is a measure of the amount of matter in the molecule. Methane boils at 65 °C and freezes at –94 °C. At 20 °C, its density is 0.7915 grams per cubic centimeter (see Density ).
Methanol readily dissolves a number of other chemicals. This property makes it an important solvent (substance that dissolves other substances) in the manufacture of dyes, medicines, and other products. In addition, methanol mixes readily with water. Solutions of methanol and water function in motor vehicles as antifreezes for windshield washer fluids and fuel lines. Such solutions remain liquid at temperatures that would freeze pure water.
A wide variety of products are manufactured from mixtures of methanol and ethanol, which is also called grain alcohol. Ethanol is an ingredient of many alcoholic beverages, but mixing it with methanol makes it denatured (unfit to drink).
A variety of substances undergo chemical reactions with methanol. For example, oxygen reacts with methanol to produce formaldehyde, a chemical used in making plastics. Organic acids react with methanol to form compounds called esters, which are used in such products as paints and varnishes. In addition, methanol can be converted to high-octane gasoline, but only by means of an expensive process.
Campers use methanol as fuel in portable stoves. Methanol also can function as a motor fuel in place of gasoline, but its rates of corrosion and combustion differ from those of gasoline. Therefore, such use of pure methanol requires adjustments to the carburetor, other engine parts, and the fuel tank.
Most commercial methanol is produced by heating carbon monoxide and hydrogen under pressure in the presence of a metal oxide catalyst (see Catalysis ). Mixtures of carbon monoxide and hydrogen can be obtained from such sources as coal, natural gas, petroleum, wood, garbage, or sewage.
See also Ethanol .
