Methanol

Not to be confused with menthol or methanal.
Methanol
Skeletal formula of methanol with some explicit hydrogens added
Spacefill model of methanol
Stereo skeletal formula of methanol with all explicit hydrogen added
Ball and stick model of methanol
Names
Preferred IUPAC name
Methanol [1]
Other names
Carbinol
Columbian spirits
Hydroxymethane
Methyl alcohol
Methyl hydrate
Methyl hydroxide
Methylic alcohol
Methylol
Pyroligneous spirit
Wood alcohol
Wood naphtha
Wood spirit
Identifiers
67-56-1 YesY
3D model ( Jmol) Interactive image
3DMet B01170
1098229
ChEBI CHEBI:17790 YesY
ChEMBL ChEMBL14688 YesY
ChemSpider 864 YesY
ECHA InfoCard 100.000.599
EC Number 200-659-6
449
KEGG D02309 YesY
MeSH Methanol
PubChem 887
RTECS number PC1400000
UNII Y4S76JWI15 YesY
UN number 1230
Properties
CH
3
OH
Molar mass 32.04 g mol−1
Appearance Colorless liquid
Density 0.792 g·cm−3 [2]
Melting point −97.6 °C (−143.7 °F; 175.6 K)
Boiling point 64.7 °C (148.5 °F; 337.8 K)
miscible
log P -0.69
Vapor pressure 13.02 kPa (at 20 °C)
Acidity (pKa) 15.5 [3]
-21.40·10−6 cm3/mol
1.33141 [4]
Viscosity 0.545 mPa×s (at 25 °C) [5]
1.69 D
Hazards [10]
Safety data sheet See: data page
GHS pictograms The flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The skull-and-crossbones pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) [6]
GHS signal word Danger [6]
H225, H301, H311, H331, H370 [6]
P210, P233, P240, P241, P242, P243, P260, P264, P270, P280, P301+310, P303+361+353, P304+340, P330 [6]
Highly Flammable F Toxic T
R-phrases R11, R23/24/25, R39/23/24/25
S-phrases (S1/2), S7, S16, S36/37, S45
NFPA 704
Flammability code 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g., gasoline) Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
3
1
0
Flash point 11 to 12 °C (52 to 54 °F; 284 to 285 K)
470 [7] °C (878 °F; 743 K)
Explosive limits 6%-36% [8]
Lethal dose or concentration (LD, LC):
LD50 ( median dose)
5628 mg/kg (rat, oral)
7300 mg/kg (mouse, oral)
12880 mg/kg (rat, oral)
14200 mg/kg (rabbit, oral) [9]
64,000 ppm (rat, 4 hr) [9]
33,082 ppm (cat, 6 hr)
37,594 ppm (mouse, 2 hr) [9]
US health exposure limits ( NIOSH):
PEL (Permissible)
TWA 200 ppm (260 mg/m3) [8]
REL (Recommended)
TWA 200 ppm (260 mg/m3) ST 250 ppm (325 mg/m3) [skin] [8]
IDLH (Immediate danger)
6000 ppm [8]
Related compounds
Related compounds
Methanethiol
Silanol
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify ( what is YesYN ?)
Infobox references

Methanol ( /ˈmɛθənɒl/), also known as methyl alcohol among others, is a chemical with the formula C H3 O H (often abbreviated MeOH). Methanol acquired the name "wood alcohol" because it was once produced chiefly as a byproduct of the destructive distillation of wood. Today, industrial methanol is produced in a catalytic process directly from carbon monoxide, carbon dioxide, and hydrogen.

Methanol is the simplest alcohol, being only a methyl group linked to a hydroxyl group. It is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to that of ethanol (drinking alcohol). [11] However, unlike ethanol, methanol is highly toxic and unfit for consumption. At room temperature, it is a polar liquid, and is used as an antifreeze, solvent, fuel, and as a denaturant for ethanol. It is also used for producing biodiesel via transesterification reaction.

Methanol is produced naturally in the anaerobic metabolism of many varieties of bacteria, and is commonly present in small amounts in the environment. As a result, the atmosphere contains a small amount of methanol vapor. But in only a few days, atmospheric methanol is oxidized by sunlight to produce carbon dioxide and water.

Methanol is also found in abundant quantities in star forming regions of space, and is used in astronomy as a marker for such regions. It is detected through its spectral emission lines. [12]

Methanol when drunk is metabolized first to formaldehyde and then to formic acid or formate salts. [13] These are poisonous to the central nervous system and may result in blindness, coma, and death. Because of these toxic properties, methanol is frequently used as a denaturant additive for ethanol manufactured for industrial uses. This addition of methanol exempts industrial ethanol (commonly known as " denatured alcohol" or "methylated spirit") from liquor excise taxation in the US and some other countries.

Toxicity

Main article: Methanol toxicity

Methanol toxicity is poisoning from methanol. [14] Symptoms may include a decreased level of consciousness, poor coordination, vomiting, abdominal pain, and a specific smell on the breath. [14] [15] Decreased vision may start as early as twelve hours after exposure. [15] Long term outcomes may include blindness and kidney failure. Toxicity and death may occur even after drinking a small amount. [14]

Methanol poisoning most commonly occurs following the drinking of windshield washer fluid. [15] This may be accidental or done purposefully in an attempt to cause death. Toxicity may also rarely occur through skin exposure or breathing in the fumes. [14] When methanol is broken down by the body it results in formaldehyde, formic acid, and formate which cause much of the toxicity. [15] The diagnosis may be suspected when there is acidosis or an increased osmol gap and confirmed by directly measuring blood levels. [14] [15] Other conditions that can produce similar symptoms include infections, exposure to other toxic alcohols, serotonin syndrome, and diabetic ketoacidosis. [15]

Early treatment increases the chance of a good outcome. Treatment consists of stabilizing the person, followed by the use of an antidote. The preferred antidote is fomepizole, with ethanol used if this is not available. Hemodialysis may also be used in those where there is organ damage or a high degree of acidosis. Other treatments may include sodium bicarbonate, folate, and thiamine. [15]

Outbreaks have occurred due to contamination of drinking alcohol. This is more common in the developing world. [15] In 2013 more than 1700 cases occurred in the United States. Those affected are often adults and male. [16] Outcomes may be good with early treatment. [14] Toxicity to methanol has been described as early as 1856. [17]