Methyl alcohol (METH-uhl AL-ko-hol) is a clear, colorless, flammable, toxic liquid with a slightly alcoholic odor and taste. Methyl alcohol is the simplest alcohol, a family of organic compounds characterized by the presence of one or more hydroxyl (-OH) groups.
Methanol; wood alcohol; wood spirit; carbinol
Carbon, hydrogen, oxygen
Miscible with water, ethyl alcohol, ether, acetone, and many other organic solvents
HOW IT IS MADE
Methyl alcohol occurs naturally in plants and animals, including humans, as the product of metabolic reactions that occur in all organisms. It also occurs in the atmosphere as the result of the decomposition of dead organisms in the soil. None of these sources is utilized for the commercial production of methyl alcohol. Instead, the primary method for the preparation of methyl alcohol is to react carbon monoxide with water at a temperature of about 250°C (480°F) and pressures of 50 to 100 atmospheres over a mixed catalyst of copper, zinc oxide, and aluminum oxide. Efforts are being made to develop other methods of synthesizing methyl alcohol. In one process, for example, simple hydrocarbons, such as methane, are oxidized over a catalyst of molybdenum metal to produce the alcohol. None of the experimental methods developed for the production of methyl alcohol can yet compete with the traditional carbon monoxide-hydrogen process, however.
COMMON USES AND POTENTIAL HAZARDS
Consumption of methyl alcohol in the United States for 2005 reached about 12 billion liters (3 billion gallons). The largest demand for the compound was in the production of MTBE (methyl-tert-butyl ether), a gasoline additive used to improve the efficiency with which a fuel burns and to reduce pollutants released to the atmosphere. Demand for the additive increased rapidly after the U.S. Congress passed the 1990 Clean Air Act Amendments requiring significant reductions in the release of certain pollutants into the atmosphere. A decade later, however, serious questions were being raised about possible serious environment dangers posed by MTBE released into the soil. In the last few years, enthusiasm for the use of MTBE has begun to disappear and a number of states have adopted bans on its use as a gasoline additive. As a result of these actions, the demand for methyl alcohol in producing MTBE has dropped dramatically in the last few years.
The next most important demand for methyl alcohol is as a raw material in the synthesis of many important organic compounds, including formaldehyde; acetic acid; chloromethanes, compounds in which the hydroxyl group and/or one or more hydrogen has been replaced by fluorine, chlorine, bromine, and/or iodine; methyl methacrylate, a compound from which acrylic plastics are made; methylamines, the source of another important class of plastics, dimethyl terephthalate, the monomer for yet another class of plastics; and other products.
- At one time, the primary method for making methyl alcohol was to heat wood in a closed space, accounting for the compound's common and popular name of "wood alcohol."
- Methyl alcohol was first isolated, although not in a pure form, by the English chemist and physicist Robert Boyle (1627–1691) although the compound was not synthesized for another two centuries. It was then produced by the French chemist Pierre Eugène Marcelin Berthelot (1827–1907).
Relatively small quantities of methyl alcohol are used in a number of other applications, including:
- As a solvent for household and industrial products;
- As a deicing agent;
- In the preparation of embalming fluids;
- As a softening agent for plastics;
- As a fuel for camp stoves, soldering torches, and race cars;
- In paint removing products;
- As an antifreeze and windshield washing fluid; and
- In the manufacture of a number of pharmaceuticals, including streptomycin, vitamins, and hormones.
Methyl alcohol poses both safety and health hazards. It is highly flammable and, with the appropriate mixture of air, explosive. It is also very toxic by ingestion, producing a variety of effects that include blurred vision, headache, dizziness, drowsiness, and nausea. Although a fatal dose is usually in the range of 100 to 250 mL, cases have been reported in which a person has died after consuming less than 30 mL of the compound. People who work with methyl alcohol in their jobs, including bookbinders, dyers, foundry workers, gilders, hat makers, ink makers, laboratory technicians, painters, photoengravers, and chemical workers, are especially at risk from methanol poisoning. The ready availability of the compound and products in which it is an ingredient means that everyone who uses such products should be aware of the health risks involved in its use. Medical attention is required immediately in case of the ingestion of methyl alcohol.
Words to Know
- A biological process that includes all of the chemical reactions that occur in cells by which fats, carbohydrates, and other compounds are broken down to produce energy and the compounds needed to build new cells and tissues.
- able to be mixed; especially applies to the mixing of one liquid with another.
- A small molecule used in polymerization reactions to produce very large molecules in which the monomer is repeated hundreds or thousands of times.
- A liquid that dissolves another substance.
- A chemical reaction in which some desired chemical product is made from simple beginning chemicals, or reactants.
FOR FURTHER INFORMATION
"Material Safety Data Sheet: Methyl Alcohol, Reagent ACS, 99.8% (GC)." Department of Chemistry, Iowa State University. http://avogadro.chem.iastate.edu/MSDS/methanol.htm (accessed on October 17, 2005).
McGrath, Kimberley A. "Methanol." World of Scientific Discovery, 2nd edition. Detroit, MI: Gale, 1999.
Salocks, Charles, and Karlyn Black Kaley. "Methanol." Technical Support Document: Toxicology Clandestine Drug Labs/Methamphetamine, Volume 1, Number 10. http://www.oehha.ca.gov/public_info/pdf/TSD%20Methanol%20Meth%20Labs%2010'8'03.pdf (accessed on October 17, 2005).
U. S. Department of Health and Human Services. "Methanol Toxicity." American Family Physician (January 1993): 163-171.
methyl alcohol: see methanol.