Formaldehyde
Overview
Formaldehyde (for-MAL-duh-hide) is a colorless, flammable gas with a strong, pungent odor that tends to polymerize readily. Polymerization occurs when individual molecules of formaldehyde combine with each other to make very large molecules called polymers. Over 4 billion kilograms (10 billion pounds) of formaldehyde were produced in the United States in 2004, the vast majority of which was used in the production of plastics and other polymers. To make handling and shipping easier and safer, the compound is usually provided as a 37 percent solution of formaldehyde in water to which has been added an additional 15 percent of methanol (methyl alcohol) to prevent polymerization.
Key Facts
Other Names:
Methanal; oxomethylene; oxomethane; methylene oxide; formic aldehyde
Formula:
HCHO
Elements:
Carbon, hydrogen, oxygen
Compound Type:
Aldehyde (organic)
State:
Gas
Molecular Weight:
30.03 g/mol
Melting Point:
−92°C (−130°F)
Boiling Point:
−19.1°C (−2.38°F)
Solubility:
Very soluble in water, alcohol, ether, and benzene
Formaldehyde was first produced accidentally in 1859 by the Russian-French chemist Alexander Mikhailovich Butlerov (1828–1886). It was first synthesized in 1867 by the German chemist August Wilhelm von Hofmann (1818–1892) who was not, however, able to collect the compound in pure form. That step was accomplished by German chemist Friedrich August Kekulé (1829–1896) in 1892.
How It Is Made
Formaldehyde occurs naturally in the atmosphere at a concentration of about 10 parts per billion (0.000 001%) partly as a by-product of plant and animal metabolism, and partly as a product of the reaction of sunlight with methane (CH4), a much more abundant component of the air. At such low concentrations, it is not a natural source of the compound for commercial or industrial uses and is produced instead by the oxidation of methanol (methyl alcohol; CH3OH) or gases extracted from petroleum (such as methane) over a catalyst of silver, copper, or iron with molybdenum oxide.
Common Uses and Potential Hazards
By far the most important application of formaldehyde is in the production of polymers and other organic chemicals. About one-quarter of commercial-use formaldehyde is used each year to make a family of polymers known as urea-formaldehyde resins, which are used to make dinnerware, particle board, fiber board, plywood, flexible foams, and insulation. Another 16 percent goes to the production of phenol-formaldehyde resins, with applications in molded and cast plastics, adhesives and bonding materials, laminating materials, brake linings, chemical equipment, machine housing, and a host of other applications. Smaller amounts of formaldehyde are used to make a variety of important chemicals including 1,4-butanediol, methylene diisocyanate, pentaerythritol, and hexamethylenetetramine. Other applications include use in controlled release fertilizers, in the production of nitroparaffin derivatives, in the treatment of textiles, and in the preservation of biological specimens. The last of these uses is probably well known to biology students; its use depends on the fact that formaldehyde kills most types of bacteria and can be used, therefore, to keep biological materials from decaying.
Formaldehyde poses a number of health hazards to humans and other animals. It may cause difficulty in breathing, headaches, fatigue, and lowered body temperature. At high levels of concentration or over long periods of exposure, formaldehyde can induce coma and death. Chronic exposure to formaldehyde is thought to be carcinogenic, producing tumors in the nose, throat, and respiratory system. People who work in factories where formaldehyde is used are at greatest risk for formaldehyde poisoning.
Interesting Facts
- Formaldehyde was one of the first organic compounds to have been discovered in outer space.
- When some vegetables, such as cabbage and brussel sprouts are cooked, they emit small amounts of formaldehyde.
Formaldehyde is now known to be a potentially serious indoor air pollutant. So many products in a home contain formaldehyde that significant levels of the compound may accumulate in a house. The primary sources of the formaldehyde are pressed wood products such as plywood and particleboard; furnishings; wallpaper; and durable press fabrics.
Words to Know
A chemical that causes cancer in humans or other animals. A material that increases the rate of a chemical reaction without undergoing any change in its own chemical structure. A 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. A compound consisting of very large molecules made of one or two small repeated units called monomers.For Further Information
"About Formaldehyde." Formaldehyde Council. http://www.formaldehyde.org/about_what.html (accessed on October 10, 2005).
"Formaldehyde (Methyl Aldehyde) Fact Sheet." Australian Government; Department of the Environment and Heritage. http://www.npi.gov.au/database/substance-info/profiles/45.html (accessed on October 10, 2005).
Gullickson, Richard. "Reference Data Sheet on Formaldehyde." Meridian Engineering & Technology. http://www.meridianeng.com/formalde.html (accessed on October 10, 2005).
"An Update on Formaldehyde-1997 Revision." U.S. Consumer Product Safety Commission. http://www.epa.gov/iaq/pubs/formald2.html (accessed on October 10, 2005).
See Also
Urea
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