Formaldehyde

Molecular Structure:

IUPAC Name: Formaldehyde
Synonyms of Formaldehyde (CAS NO.50-00-0): Aldehyd mravenci ; Aldehyde formique ; Aldeide formica ; Dormol ; Formaldehyd ; Formaline ; Oxymethylene
CAS NO: 50-00-0
Molecular formula: CH₂O
Molecular Weight: 30.026 g/mol
Density: 1.09 g/mL at 25 °C
H bond acceptors: 1
H bond donors: 0
Freely Rotating Bonds: 0
Polar Surface Area: 17.07 Å²
Index of Refraction: 1.235
Molar Refractivity: 6.53 cm³
Molar Volume: 43.8 cm³
Surface Tension: 12.6 dyne/cm
Appearance: colorless gas
Melting point: -92 °C
Boiling point: -21 °C 
Flashing point: 133 °F
Solubility in water: very high
Vapor density: 1.03 (vs air)
Vapor pressure: 52 mm Hg ( 37 °C)
Product Categories: Biocides;Chemistry
SMILES: O=C
InChI: InChI=1/CH2O/c1-2/h1H2
InChIKey: WSFSSNUMVMOOMR-UHFFFAOYAT
Std. InChI: InChI=1S/CH2O/c1-2/h1H2
Std. InChIKey: WSFSSNUMVMOOMR-UHFFFAOYSA-N

 Formaldehyde was first reported by the Russian chemist Aleksandr Butlerov (1828-1886), but it was conclusively identified by August Wilhelm von Hofmann.

 Formaldehyde (CAS NO.50-00-0) is a common building block for the synthesis of more complex compounds and materials. As a disinfectant and biocide: as it kills most bacteria and fungi (including their spores), an aqueous solution of formaldehyde can be useful as a disinfectant . It is also used as a preservative in vaccines. In photography: Formaldehyde can be used in low concentrations for process C-41 (color negative film) stabilizer in the final wash step. Tissue fixative and embalming agent: Formaldehyde solutions are used as a fixative for microscopy and histology. Formaldehyde-based solutions are also used in embalming to disinfect and temporarily preserve human and animal remains.

 Formaldehyde (CAS NO.50-00-0) is produced solely from methanol by using a silver catalyst or a metal oxide catalyst. Either process can be air oxidation or simple dehydrogenation.
          2CH₃OH + O₂ → 2HCH=O + 2H₂O
             CH₃OH → HCH=O + H₂
Those two reactions occur simultaneously in commercial units in a balanced autothermal reaction because the oxidative reaction furnishes the heat to cause the dehydrogenation to take place.
 In the process, fresh and recycle methanol are vaporized, superheated, and passed into the methanol-air mixer. Atmospheric air is purified, compressed, and preheated to 54 °C in a finned heat exchanger.
The products leave the converter (a water-jacketed vessel containing the catalyst) at 620 °C and at 34 to 69 kPa absolute. About 65 percent of the methanol is converted per pass. Temperatures are on the order of 450 to 900 °C and there is a short contact time of 0.01 second.
 The reactor effluent contains about 25% formaldehyde, which is absorbed with the excess methanol and piped to the make tank. The latter feeds the methanol column for separation of recycle methanol overhead, the bottom stream containing the formaldehyde and a few percent methanol. The water intake adjusts the formaldehyde(50-00-0) to 37% strength (marketed as formalin). The catalyst is easily poisoned so stainless-steel equipment must be used to protect the catalyst from metal contamination.

NTP 10th Report on Carcinogens. IARC Cancer Review: Group 2A IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 (1987),p. 211.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Human Inadequate Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 29 (1982),p. 345.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Animal Sufficient Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 29 (1982),p. 345.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . EPA Genetic Toxicology Program. Reported in EPA TSCA Inventory. EPA Extremely Hazardous Substances List.

Hazard Codes: T
Risk Statements: 34-40-43-39/23/24/25
34: Causes burns
40: Limited evidence of a carcinogenic effect
43: May cause sensitization by skin contact
39/23/24/25: Toxic: danger of very serious irreversible effects through inhalation, in contact with skin and if swallowed
Safety Statements: 51-45-36/37/39-26
26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice
45: In case of accident or if you feel unwell, seek medical advice immediately (show label where possible)
51: Use only in well-ventilated areas
36/37/39: Wear suitable protective clothing, gloves and eye/face protection 
RIDADR: UN 1198 3/PG 3
WGK Germany: 2
RTECS: LP8925000
F: 10
HazardClass: 3
PackingGroup: III
Confirmed carcinogen with experimental carcinogenic, tumorigenic, and teratogenic data. Human poison by ingestion. Experimental poison by ingestion, skin contact, inhalation, intravenous, intraperitoneal, and subcutaneous routes. Human systemic effects by inhalation: lachrymation, olfactory changes, aggression, and pulmonary changes. Experimental reproductive effects. Human mutation data reported. A human skin and eye irritant. If swallowed it causes violent vomiting and diarrhea that can lead to collapse. Frequent or prolonged exposure can cause hypersensitivity leading to contact dermatitis, possibly of an eczematoid nature. An air concentration of 20 ppm is quickly irritating to eyes. A common air contaminant.

Flammable liquid when exposed to heat or flame; can react vigorously with oxidizers. A moderate explosion hazard when exposed to heat or flame. The gas is a more dangerous fire hazard than the vapor. Should formaldehyde be involved in a fire, irritating gaseous formaldehyde may be evolved. When aqueous formaldehyde solutions are heated above their flash points, a potential for an explosion hazard exists. High formaldehyde concentration or methanol content lowers the flash point. Reacts with sodium hydroxide to yield formic acid and hydrogen. Reacts with NO_x at about 180°; the reaction becomes explosive. Also reacts violently with perchloric acid + aniline, performic acid, nitromethane, magnesium carbonate, H₂O₂. Moderately dangerous because of irritating vapor that may exist in toxic concentrations locally if storage tank is ruptured. To fight fire, stop flow of gas (for pure form); alcohol foam for 37% methanol-free form. When heated to decomposition it emits acrid smoke and fumes. See also ALDEHYDES.

OSHA PEL: TWA 0.75 ppm; STEL 2 ppm
ACGIH TLV: CL 0.3 ppm (sensitizer); Suspected Human Carcinogen
DFG MAK: 0.5 ppm (0.6 mg/m³); Confirmed Animal Carcinogen with Unknown Relevance to Humans
NIOSH REL: (Formaldehyde) Limit to lowest feasible level
DOT Classification:  9; Label: None (UN 2209); DOT Class: 3; Label: Flammable Liquid (UN 1198)

For occupational chemical analysis use OSHA: #ID-102 or NIOSH: Formaldehyde (Oxazolidine), 2502; (Chromotropic Acid), 3500.

 Formaldehyde (CAS NO.50-00-0) is the simplest aldehyde, ans it exists in water as the hydrate H₂C(OH)₂. Aqueous solutions of formaldehyde are referred to as formalin. Formaldehyde(50-00-0) is an intermediate in the oxidation (or combustion) of methane as well as other carbon compounds, e.g. forest fires, in automobile exhaust, and in tobacco smoke.
In the pure form, Formaldehyde in the pure form is a gas with a boiling point of -21°C but is unstable and readily trimerizes to trioxane or polymerizes to paraformaldehyde. Formaldehyde is stable only in water solution, commonly 37 to 56% formaldehyde by weight and often with methanol (3 to15%) present as a stabilizer.