Formaldehyde 63847 225975691 2008-07-16T08:06:30Z Lt Lugubrious 7456826 Cosmetic changes {{Chembox new | Name = Formaldehyde | ImageFileL1 = Formaldehyde-2D.svg | ImageSizeL1 = 120px | ImageFileR1 = Formaldehyde-3D-balls.png | ImageSizeR1 = 120px | ImageFile2 = Formaldehyde-3D-vdW.png | ImageSize2 = 150px | IUPACName= Methanal | OtherNames = formol, methyl aldehyde, methylene oxide| Section1 = {{Chembox Identifiers | SMILES = C=O | CASNo = 50-00-0 | RTECS = LP8925000 }} | Section2 = {{Chembox Properties | Formula = CH<sub>2</sub>O | MolarMass = 30.03&thinsp;g·mol<sup>−1</sup> | Appearance = colorless gas | Density = 1&thinsp;kg·m<sup>−3</sup>, gas | Solubility = > 100&thinsp;g/100 ml (20&thinsp;°C) | MeltingPt = -117&thinsp;°C (156&thinsp;[[Kelvin|K]]) | BoilingPt = -19.3&thinsp;°C (253.9&thinsp;K) }} | Section3 = {{Chembox Structure | MolShape = trigonal planar | Dipole = 2.33168(1) [[Debye|D]] }} | Section7 = {{Chembox Hazards | MainHazards = toxic, flammable | NFPA-H = 3 | NFPA-F = 2 | NFPA-R = 2 | FlashPt = -53 °C | RPhrases = {{R23/24/25}}, {{R34}}, {{R40}}, {{R43}}| SPhrases = {{S1/2}}, {{S26}}, {{S36/37}}, {{S39}}, {{S45}}, {{S51}} }} | Section8 = {{Chembox Related | Function = [[aldehydes]] | OtherFunctn = [[acetaldehyde]] [[benzaldehyde]] | OtherCpds = [[ketone]]s [[carboxylic acid]]s}} }} '''Formaldehyde''' is a [[chemical compound]] with the [[chemical formula|formula]] H<sub>2</sub>CO. It is the simplest [[aldehyde]]—an organic compound containing a terminal [[carbonyl]] group: it consists of exactly one carbonyl. It was first [[Chemical_synthesis|synthesized]] by the [[Russia]]n chemist [[Aleksandr Butlerov]] (1828-1886), but was conclusively identified by [[August Wilhelm von Hofmann]].<ref>J Read, Text-Book of Organic Chemistry, G Bell & Sons, London, 1935</ref> Formaldehyde exists in several forms aside from H<sub>2</sub>CO: the cyclic trimer [[trioxane]] and the polymer [[Polyoxymethylene|paraformaldehyde]]. It exists in water as the hydrate H<sub>2</sub>C(OH)<sub>2</sub>. Aqueous solutions of formaldehyde are referred to as '''formalin'''. "100%" formalin consists of a saturated solution of formaldehyde (roughly 40% by mass) in water, with a small amount of [[stabilizer (chemistry)|stabilizer]], usually [[methanol]] to limit [[oxidation]] and [[polymerization]]. Formaldehyde is an intermediate in the oxidation (or [[combustion]]) of [[methane]] as well as other carbon compounds, e.g. [[forest fire]]s, in [[automobile]] exhaust, and in [[tobacco smoke]]. It is produced in the [[Earth's atmosphere|atmosphere]] by the action of sunlight and [[oxygen]] on atmospheric [[methane]] and other [[hydrocarbon]]s; thus, it becomes part of [[smog]]. Small amounts of formaldehyde are produced as a [[metabolism|metabolic]] byproduct in most organisms, including [[humans]]. == Production == Formaldehyde is produced industrially by the catalytic oxidation of [[methanol]]. The most common catalysts are [[silver]] metal or a mixture of an [[iron oxide]] with [[molybdenum]] and [[vanadium]]. In the more commonly used FORMOX process methanol and oxygen react at ca 250-400 °C in presence of iron oxide in combination with molybdenum and/or vanadium to produce formaldehyde according to the [[chemical equation]] : 2 [[methanol|CH<sub>3</sub>OH]] + [[oxygen|O<sub>2</sub>]] → 2 H<sub>2</sub>CO + 2 [[water (molecule)|H<sub>2</sub>O]] The silver-based catalyst is usually operated at a higher temperature, about 650 °C. Two chemical reactions on it simultaneously produce formaldehyde: that shown above and the [[dehydrogenation]] reaction : CH<sub>3</sub>OH → H<sub>2</sub>CO + [[hydrogen|H<sub>2</sub>]] Formaldehyde is readily [[oxidation|oxidized]] by atmospheric oxygen to form [[formic acid]]. Formic acid is found in ppm levels in commercial formaldehyde. Formalin can be produced on a smaller scale using a whole range of other methods including conversion from ethanol instead of the normally-fed methanol feedstock. Such methods are of less commercial importance. == Organic chemistry == Formaldehyde is a central building block in the synthesis of many other compounds. It exhibits most of the chemical properties of other aldehydes but is more reactive. Formaldehyde is a good [[electrophile]], participating in [[electrophilic aromatic substitution]] reactions with [[aromatic compound]]s, and can undergo [[electrophilic addition]] reactions with [[alkene]]s. Formaldehyde undergoes a [[Cannizzaro reaction]] in the presence of [[base (chemistry)| basic]] [[catalyst]]s to produce [[formic acid]] and methanol. Condensation with acetaldehyde affords [[pentaerythritol]].<ref>{{OrgSynth | title = Pentaerythritol | author= H. B. J. Schurink | collvol = 1 | year= 1941 | volume = 1 | pages= 425 | prep = CV1P0425}}</ref> Condensation with phenols gives [[phenol-formaldehyde resin]]s. With 4-substituted phenols one obtains calixarenes.<ref>{{OrgSynth | author = Gutsche, C. D.; Iqbal, M. | title = <nowiki>p-tert-Butylcalix[4]arene</nowiki> | collvol = 8 | collvolpages = 75 | year = 1993 | prep = CV8P0075}}</ref> When combined with hydrogen sulfide it forms [[trithiane]].<ref>{{OrgSynth | author = Bost, R. W.; Constable, E. W. | title = sym-Trithiane | collvol = 2 | collvolpages = 610 | year = 1943 | prep = CV2P0610}}</ref> : 3 CH<sub>2</sub>O + 3 H<sub>2</sub>S → (CH<sub>2</sub>S)<sub>3</sub> + 3 H<sub>2</sub>O == Biology == Formaldehyde solutions are used as a [[Fixation (histology)|fixative]] for [[microscopy]] and [[histology]]. Pure solutions that are free of the oxidation product [[formic acid]] and of the [[stabilizer]] [[methanol]] are often produced by [[depolymerization]] of [[paraformaldehyde]] in hot water. Formaldehyde (and its [[oligomer]]s and hydrates) are rarely encountered in living organisms. [[Methanogenesis]], which can start from many C1 sources, proceeds via the equivalent of formaldehyde, but this one-carbon species is masked as a [[methylene]] group carried by [[methanopterin]]. The formaldehyde is the primary cause of the [[methanol]]'s toxicity, since methanol is metabolised into toxic formaldehyde by [[alcohol dehydrogenase]]. == Applications == === As a disinfectant and biocide === An aqueous solution of formaldehyde can be useful as a disinfectant as it kills most [[bacterium|bacteria]] and fungi (including their spores). It is also used as a [[preservative]] in [[vaccine]]s. Formaldehyde solutions are applied topically in medicine to dry the skin, such as in the treatment of [[wart]]s. Many aquarists use formaldehyde as a treatment for the parasite [[ichthyophthirius]]. Formaldehyde preserves or [[Fixation (histology)|fixes]] tissue or cells by irreversibly cross-linking primary [[amino group]]s in proteins with other nearby nitrogen atoms in protein or [[DNA]] through a -CH<sub>2</sub>- linkage. This is exploited in [[ChIP-on-chip]] transcriptomics experiments. Formaldehyde is also used as a denaturing agent in [[RNA]] gel [[electrophoresis]], preventing RNA from forming secondary structures. Formaldehyde is converted to [[formic acid]] in the body, leading to a rise in blood acidity ([[acidosis]]). === Industry === Formaldehyde is a common building block for the synthesis of more complex compounds and materials. Most formaldehyde is used in the production of [[polymers]] and other chemicals. When reacted with [[phenol]], [[urea]], or [[melamine]] formaldehyde produces, respectively, hard [[thermoset]] [[phenol formaldehyde resin]], [[urea formaldehyde resin]], and [[melamine resin]]. These resins are commonly used in permanent adhesives such as those used in [[plywood]] or [[carpet]]ing. It is used as the wet-strength resin added to sanitary paper products such as (listed in increasing concentrations injected into the paper machine headstock chest) facial tissue, table napkins, and roll towels. They are also foamed to make [[Thermal insulation|insulation]], or [[casting|cast]] into moulded products. Production of formaldehyde resins accounts for more than half of formaldehyde consumption. Many of these are polyfunctional [[alcohol]]s such as [[pentaerythritol]], which is used to make [[paint]]s and [[explosive]]s. Other formaldehyde derivatives include [[methylene diphenyl diisocyanate]], an important component in [[polyurethane]] paints and foams, and [[hexamine]], which is used in phenol-formaldehyde resins as well as the explosive [[RDX]]. Formaldehyde is still used in low concentrations for process [[C-41]] (color negative film) stabilizer in the final wash step, as well as in the [[E-6 process|process E-6]] pre-bleach step, to obviate the need for it in the final wash. Formaldehyde is used to produce glues used in the manufacture of [[particleboard]], [[plywood]], [[veneer]]s, and other wood products, as well as spray-on insulating foams.{{Fact|date=June 2007}} Formaldehyde, along with 18 [[Concentration#molarity|M]] (concentrated) [[sulfuric acid]] (the entire solution often called the [[Marquis reagent]])<ref>[http://www.dancesafe.org/documents/druginfo/testkits.php DanceSafe: testing kit info<!-- Bot generated title -->]</ref>, is used as an [[MDMA]] "testing kit" by such groups as [[Dancesafe]] as well as MDMA consumers. The solution alone cannot verify the presence of MDMA but reacts with many other chemicals that the MDMA tablet itself may be adulterated with. The reaction itself produces colors that correlate with these components. The [[textile industry]] uses formaldehyde-based resins as finishers to make fabrics crease-resistant.{{Fact|date=June 2007}} It is also used as an ingredient by some Shampoo manufacturers. === Embalming === Formaldehyde-based solutions are used in [[embalming]] to disinfect and temporarily preserve human remains. It is the ability of formaldehyde to fix the tissue that produces the tell-tale firmness of flesh in an embalmed body. Whereas other heavier [[aldehydes]] produce a similar firming action none approaches the completeness of formaldehyde. Several European countries restrict the use of formaldehyde, including the import of formaldehyde-treated products and embalming, and the European Union is considering a complete ban on formaldehyde usage (including embalming), subject to a review of List 4B of the Technical Annex to the Report from the Commission to the European Parliament and the Council on the Evaluation of the Active Substances of Plant Protection Products by the European Commission Services. Countries with a strong tradition of embalming corpses, such as Ireland and other colder-weather countries, have raised concerns. The European Union decided on September 22, 2007 to ban Formaldehyde use throughout Europe due to its carcinogenic properties.<ref>[http://www.webwire.com/ViewPressRel.asp?aId=41468 Formaldehyde Ban set for 22 Sept 2007<!-- Bot generated title -->]</ref> == Safety == Occupational exposure to formaldehyde by inhalation is mainly from three types of sources: [[Thermal decomposition|thermal]] or [[chemical decomposition]] of formaldehyde-based resins, formaldehyde emission from [[aqueous]] solutions (for example, embalming fluids), and the production of formaldehyde resulting from the [[combustion]] of a variety of organic compounds (for example, exhaust gases). Formaldehyde can be toxic, allergenic, and carcinogenic.<ref>IARC Press Release June 2004, http://www.iarc.fr/ENG/Press_Releases/archives/pr153a.html</ref> Because formaldehyde resins are used in many construction materials it is one of the more common indoor air pollutants.<ref>Indoor Air Pollution in California, Final Report, California Air Resources Board (2005) http://www.arb.ca.gov/research/indoor/ab1173/finalreport.htm, at pages 65 – 70.</ref> At concentrations above 0.1 ppm in air formaldehyde can irritate the eyes and [[mucous membrane]]s, resulting in watery eyes. Formaldehyde inhaled at this concentration may cause headaches, a burning sensation in the throat, and difficulty breathing, as well as triggering or aggravating asthma symptoms.<ref>Symptoms of Low-Level Formaldehyde Exposures, Health Canada, http://www.hc-sc.gc.ca/iyh-vsv/environ/formaldehyde_e.html</ref> Formaldehyde is classified as a probable human carcinogen by the U.S. Environmental Protection Agency. The International Agency for Research on Cancer (IARC) has determined that there is "sufficient evidence" that occupational exposure to formaldehyde causes nasopharyngeal cancer in humans. <ref>http://monographs.iarc.fr/ENG/Monographs/vol88/volume88.pdf "Formaldehyde".</ref> The United States Environmental Protection Agency [[USEPA]] allows no more than 0.016 ppm formaldehyde in the air in new buildings constructed for that agency.<ref> Testing for Indoor Air Quality, Baseline IAQ, and Materials, http://www.epa.gov/rtp/new-bldg/environmental/s_01445.htm</ref> Formaldehyde can cause allergies and is part of the standard patch test series. People with formaldehyde allergy are advised to avoid [[formaldehyde releasers]] as well (''e.g.'', [[Quaternium-15]], [[imidazolidinyl urea]], and [[diazolidinyl urea]]).<ref>{{cite web | title = Formaldehyde allergy: What is formaldehyde and where is it found? | url = http://dermnetnz.org/dermatitis/formaldehyde-allergy.html | publisher = DermNet NZ}}</ref> Formaldehyde has been banned in cosmetics in both [[Sweden]] and [[Japan]].{{Fact|date=February 2008}} === FEMA Trailer Formaldehyde Exposures === The [[Federal Emergency Management Agency]] (FEMA) provided travel trailers and mobile homes starting in [[2006]] for habitation by Gulf Coast residents displaced by [[Hurricane Katrina]] and [[Hurricane Rita]]. Some of the people who moved into the trailers complained of breathing difficulties, nosebleeds, and persistent headaches. Formaldehyde exposure can cause burning eyes and nose, coughing, difficulty breathing, headaches, and has been shown to be carcinogenic, causing nasal and nasopharyngeal [[cancer]] and possibly leukemia.<ref>{{cite web | publisher = [[National Cancer Institute]] | url = http://www.cancer.gov/cancertopics/factsheet/Risk/formaldehyde | title = Formaldehyde and Cancer: Questions and Answers | date = 2004-07-30}}</ref> Formaldehyde-catalyzed [[resins]] are used in the manufacture of [[engineered wood products]] such as [[particle board]], [[medium-density fibreboard]] (MDF), [[plywood]], and [[oriented strand board]] (OSB), all of which have applications in site-built homes, mobile homes, and travel trailers. The United States Centers For Disease Control and Prevention ([[CDC]]) performed indoor air quality testing for formaldehyde <ref>http://www.cdc.gov/niosh/nmam/pdfs/2016.pdf</ref> in some of the units. On Thursday, February 14, 2008 the CDC announced that potentially hazardous levels of formaldehyde were found in many of the travel trailers and mobile homes provided by the agency.<ref>[http://www.cdc.gov/nceh/ehhe/trailerstudy/pdfs/SummaryofStudyFindings.pdf Formaldehyde Levels in FEMA-Supplied Trailers<!-- Bot generated title -->]</ref><ref>{{cite news | title = Are FEMA trailers ‘toxic tin cans’? | url = http://www.msnbc.msn.com/id/14011193/from/ET/#storyContinued | author = Mike Brunker | date = 2006-07-25 | publisher = [[MSNBC]]}}</ref> The CDC's preliminary evaluation of a scientifically established random sample of 519 travel trailers and mobile homes tested between Dec. 21, 2007 and Jan. 23, 2008 (2+ years after manufacture) showed average levels of formaldehyde in all units of about 77 parts per billion (ppb). Long-term exposure to levels in this range can be linked to an increased risk of cancer and, at levels above this range, there can also be a risk of respiratory illness. These levels are higher than expected in indoor air, where levels are commonly in the range of 10-20 ppb, and are higher than the Agency for Toxic Substance Disease Registry (ATSDR, division of the CDC) Minimal Risk Level (MRL) of 8 ppb <ref>[http://www.atsdr.cdc.gov/mrls/index.html ATSDR - Minimal Risk Levels for Hazardous Substances (MRLs)<!-- Bot generated title -->]</ref>. Levels measured ranged from 3 ppb to 590 ppb.<ref>[http://www.fema.gov/news/newsrelease.fema?id=42606 FEMA: CDC Releases Results Of Formaldehyde Level Tests<!-- Bot generated title -->]</ref> The Federal Emergency Management Agency, which requested the testing by the CDC, said it would work aggressively to relocate all residents of the temporary housing as soon as possible. Lawsuits are being filed against FEMA as a result of the exposures.<ref>[http://www.washingtonpost.com/wp-dyn/content/article/2007/08/08/AR2007080801758.html Suit Filed Over FEMA Trailer Toxins - washingtonpost.com<!-- Bot generated title -->]</ref> === See also === * [[Aldehyde]] * [[Formic acid]] * [[paraformaldehyde]] == References == <references/> == External links == * {{ICSC|0275|02}} (''gas'') * {{ICSC|0695|06}} (''solution'') * [http://monographs.iarc.fr/ENG/Monographs/vol88/volume88.pdf "Formaldehyde"], [[IARC]] Monograph * [http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s089form.pdf Formaldehyde (gas)] from the 11th Report on Carcinogens of the [[U.S.]] [[National Toxicology Program]] (.pdf file) * [http://www.npi.gov.au/database/substance-info/profiles/45.html Formaldehyde fact sheet] from the [[Australia]]n National Pollutant Inventory * [http://www.cdc.gov/niosh/npg/npgd0293.html NIOSH Pocket Guide to Chemical Hazards] * [http://www.kodak.com/global/en/service/Zmanuals/z131.shtml Process C-41 Using KODAK FLEXICOLOR Chemicals Publication Z-131] * [http://www.formaldehyde.org/ Formaldehyde Council] * [http://chemsub.online.fr?chemname=formaldehyde Formaldehyde Data Sheet], ChemSub Online * [http://www.irsst.qc.ca/files/documents/PubIRSST/RG-473.pdf Prevention guide – Formaldehyde in the work place] * [http://www.cdc.gov/niosh/topics/formaldehyde/ National Institute for Occupational Safety and Health - Formaldehyde Page] [[Category:Aldehydes]] [[Category:IARC Group 1 carcinogens]] [[Category:Hazardous air pollutants]] [[Category:Water pollution]] [[Category:anatomical preservation]] [[Category:Occupational safety and health]] [[bg:Формалдехид]] [[ca:Formaldehid]] [[cs:Formaldehyd]] [[da:Formaldehyd]] [[de:Formaldehyd]] [[et:Formaldehüüd]] [[el:Φορμαλδεΰδη]] [[es:Formaldehído]] [[eo:Formaldehido]] [[fa:فرمالدهید]] [[fr:Méthanal]] [[ko:폼알데하이드]] [[id:Formaldehida]] [[it:Formaldeide]] [[he:פורמלין]] [[kk:Формальдегид]] [[la:Methanal]] [[lv:Formaldehīds]] [[lt:Formaldehidas]] [[hu:Formaldehid]] [[nl:Formaldehyde]] [[ja:ホルムアルデヒド]] [[no:Formaldehyd]] [[pl:Aldehyd mrówkowy]] [[pt:Metanal]] [[ro:Formaldehidă]] [[ru:Формальдегид]] [[simple:Formaldehyde]] [[sk:Formaldehyd]] [[su:Formaldehida]] [[fi:Formaldehydi]] [[sv:Formaldehyd]] [[th:ฟอร์มาลดีไฮด์]] [[vi:Fomanđêhít]] [[zh:甲醛]]