General Description
A colorless fairly volatile liquid with a faintly sweet pungent odor like that of ethyl alcohol. Completely mixes with water. The vapors are slightly heavier than air and may travel some distance to a source of ignition and flash back. Any accumulation of vapors in confined spaces, such as buildings or sewers, may explode if ignited. Used to make chemicals, to remove water from automotive and aviation fuels, as a solvent for paints and plastics, and as an ingredient in a wide variety of products.
Reactivity Profile
METHANOL(67-56-1) reacts violently with acetyl bromide [Merck 11th ed. 1989]. Mixtures with concentrated sulfuric acid and concentrated hydrogen peroxide can cause explosions. Reacts with hypochlorous acid either in water solution or mixed water/carbon tetrachloride solution to give methyl hypochlorite, which decomposes in the cold and may explode on exposure to sunlight or heat. Gives the same product with chlorine. Can react explosively with isocyanates under basic conditions. The presence of an inert solvent mitigates this reaction [Wischmeyer 1969]. A violent exothermic reaction occurred between methyl alcohol and bromine in a mixing cylinder [MCA Case History 1863. 1972]. A flask of anhydrous lead perchlorate dissolved in METHANOL(67-56-1) exploded when METHANOL(67-56-1) was disturbed [J. Am. Chem. Soc. 52:2391. 1930]. P4O6 reacts violently with METHANOL(67-56-1). (Thorpe, T. E. et al., J. Chem. Soc., 1890, 57, 569-573). Ethanol or METHANOL(67-56-1) can ignite on contact with a platinum-black catalyst. (Urben 1794).
Air & Water Reactions
Highly flammable. Soluble in water in all proportions.
Hazard
Flammable, dangerous fire risk. Explosive
limits in air 6–36.5% by volume. Toxic by ingestion
(causes blindness). Headache, eye damage, dizziness, and nausea.
Health Hazard
Exposure to excessive vapor causes eye irritation, head-ache, fatigue and drowsiness. High concentrations can produce central nervous system depression and optic nerve damage. 50,000 ppm will probably cause death in 1 to 2 hrs. Can be absorbed through skin. Swallowing may cause death or eye damage.
Fire Hazard
Behavior in Fire: Containers may explode.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Shipping
UN1230 Methanol, Hazard Class: 3; Labels:
3-Flammable liquid, 6.1-Poisonous material. (International)
Incompatibilities
Methanol reacts violently with strong
oxidizers, causing a fire and explosion hazard.
Description
Methyl alcohol, also known as methanol or wood alcohol, is a clear, colorless, flammable liquid
that is the simplest alcohol.
World production of methanol is approximately 8.5 billion gallons annually. Methanol
is produced industrially, starting with the production of synthesis gas or syngas. Syngas used
in the production of methyl alcohol is a mixture of carbon monoxide and hydrogen formed
when natural gas reacts with steam or oxygen. Methyl alcohol is then synthesized
from carbon monoxide and hydrogen.
Methyl alcohol is poisonous and is commonly used to denature ethyl alcohol. Methanol
poisoning results from ingestion, inhalation of methanol vapors, or absorption through
the skin. Methanol is transformed in the body to formaldehyde (H2CO) by the enzyme
alcohol dehydrogenase.The formaldehyde is then metabolized to formic acid (HCOOH)by aldehyde dehydrogenase.
Waste Disposal
Consult with environmental
regulatory agencies for guidance on acceptable disposal
practices. Generators of waste containing this contaminant
(≥100 kg/mo) must conform to EPA regulations governing
storage, transportation, treatment, and waste disposal.
Incineration
Physical properties
Clear, colorless liquid with a characteristic alcoholic odor. Odor threshold concentrations ranged
from 8.5 ppbv (Nagata and Takeuchi, 1990) to 100.0 ppmv (Leonardos et al., 1969).
Experimentally determined detection and recognition odor threshold concentrations were 5.5
mg/m3 (4.2 ppmv) and 69 mg/m3 (53 ppmv), respectively (Hellman and Small, 1974).
History
It was first isolated in 1661 by the Irish chemist Robert Boyle
(1627–1691) who prepared it by the destructive distillation of boxwood, giving it the name
spirit of box, and the name wood alcohol is still used for methyl alcohol. Methyl alcohol is also
called pyroxylic spirit; pyroxylic is a general term meaning distilled from wood and indicates
that methyl alcohol is formed during pyrolysis of wood. The common name was derived in the
mid-1800s. The name methyl denotes the single carbon alkane methane in which a hydrogen
atom has been removed to give the methyl radical. The word alcohol is derived from Arabic
al kuhul.
Definition
ChEBI: The primary alcohol that is the simplest aliphatic alcohol, comprising a methyl and an alcohol group.
Production Methods
Modern industrial-scale methanol production is exclusively
based on synthesis from pressurized mixtures of hydrogen,
carbon monoxide, and carbon dioxide gases in the presence
of catalysts. Based on production volume, methanol has
become one of the largest commodity chemicals produced
in the world.
Reactions
Methyl alcohol is a versatile material, reacting (1) with sodium metal, forming sodium methylate, sodium methoxide CH3ONa plus hydrogen gas, (2) with phosphorus chloride, bromide, iodide, forming methyl chloride, bromide, iodide, respectively, (3) with H2SO4 concentrated, forming dimethyl ether (CH3)2O, (4) with organic acids, warmed in the presence of H2SO4, forming esters, e.g., methyl acetate CH3COOCH3, [CAS: 79-20-9], methyl salicylate C6H4(OH)·COOCH3, possessing characteristic odors, (5) with magnesium methyl iodide in anhydrous ether (Grignard’s solution), forming methane as in the case of primary alcohols, (6) with calcium chloride, forming a solid addition compound 4CH3OH·CaCl2, which is decomposed by H2O, (7) with oxygen, in the presence of heated smooth copper or silver forming formaldehyde. The density of pure methyl alcohol is 0.792 at 20 °C compared with H2O at 4 °C (the corresponding figure for ethyl alcohol is 0.789), and the percentage of methyl alcohol present in a methyl alcohol-water solution may be determined from the density of the sample.
World Health Organization (WHO)
Methanol has been subjected to abuse by consumption as a
substitute for ethanol. Its toxic metabolites cause irreversible blindness and severe
metabolic acidosis, and are ultimately fatal. Methanol continues to be used as an
industrial solvent.
Flammability and Explosibility
Methanol is a flammable liquid (NFPA rating = 3) that burns with an invisible flame
in daylight; its vapor can travel a considerable distance to an ignition source and
"flash back." Methanol-water mixtures will burn unless very dilute. Carbon dioxide
or dry chemical extinguishers should be used for methanol fires.
reaction suitability
reaction type: volumetric
Chemical Reactivity
Reactivity with Water No reaction; Reactivity with Common Materials: No reaction; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization:Not pertinent; Inhibitor of Polymerization: Not pertinent.
Potential Exposure
Drug,Mutagen; Reproductive Effector; Human Data; PrimaryIrritant. Methyl alcohol is used as a starting material inorganic synthesis of chemicals, such as formaldehyde,methacrylates, methyl amines, methyl halides, ethylene glycol, and pesticides, and as an industrial solvent for inks, resins, adhesives, and dyes. It is an ingredient in paint and varnish removers, cleaning and dewaxing preparations, spirit duplicating fluids, embalming fluids, antifreeze mixtures, and enamels, and is used in the manufacture of photographic film, plastics, celluloid, textile soaps, wood stains, coated fabrics, shatterproof glass, paper coating, waterproofing formulations, artificial leather, and synthetic indigo and other dyes. It has also been used as an extractant in many other processes, an antidetonant fuel-injection fluid for aircraft, a rubber accelerator, and a denaturant for ethyl alcohol.
Source
Methanol occurs naturally in small-flowered oregano (5 to 45 ppm) (Baser et al., 1991),
Guveyoto shoots (700 ppb) (Baser et al., 1992), orange juice (0.8 to 80 ppm), onion bulbs,
pineapples, black currant, spearmint, apples, jimsonweed leaves, soybean plants, wild parsnip,
blackwood, soursop, cauliflower, caraway, petitgrain, bay leaves, tomatoes, parsley leaves, and
geraniums (Duke, 1992).
Methanol may enter the environment from methanol spills because it is used in formaldehyde
solutions to prevent polymerization (Worthing and Hance, 1991).
Environmental Fate
Biological. In a 5-d experiment, [14C]methanol applied to soil water suspensions under aerobic
and anaerobic conditions gave 14CO2 yields of 53.4 and 46.3%, respectively (Scheunert et al.,
1987). Heukelekian and Rand (1955) reported a 5-d BOD value of 0.85 g/g which is 56.7% of the
ThOD value of 1.50 g/g. Using the BOD technique to measure biodegradation, the mean 5-d BOD
value (mM BOD/mM methanol) and ThOD were 0.93 and 62.0%, respectively (Vaishnav et al.,
1987).
Photolytic. Photooxidation of methanol in an oxygen-rich atmosphere (20%) in the presence of
chlorine atoms yielded formaldehyde and hydroxyperoxyl radicals. The reaction is initiated via
hydrogen abstraction by OH radicals or chlorine atoms yielding a hydroxymethyl radical.
Chlorine, formaldehyde, carbon monoxide, hydrogen peroxide, and formic acid were detected
(Whitbeck, 1983). Reported rate constants for the reaction of methanol and OH radicals in the
atmosphere: 5.7 x 10-11 cm3/mol·sec at 300 K (Hendry and Kenley, 1979), 5.7 x 10-8 L/mol·sec
(second-order) at 292 K (Campbell et al., 1976), 1.00 x 10-12 cm3/molecule·sec at 292 K (Meier et
al., 1985), 7.6 x 10-13 cm3/molecule·sec at 298 K (Ravishankara and Davis, 1978), 6.61 x 10-13
cm3/molecule·sec at room temperature (Wallington et al., 1988a). Based on an atmospheric OH
concentration of 1.0 x 106 molecule/cm3, the reported half-life of methanol is 8.6 d (Grosjean,
1997).
Chemical/Physical. In a smog chamber, methanol reacted with nitrogen dioxide to give methyl
nitrite and nitric acid (Takagi et al., 1986). The formation of these products was facilitated when
this experiment was accompanied by UV light (Akimoto and Takagi, 1986).
Methanol will not hydrolyze because it does not have a hydrolyzable functional group (Kollig,
1993).
At an influent concentration of 1,000 mg/L, treatment with GAC resulted in an effluent
concentration of 964 mg/L. The adsorbability of the carbon used was 7 mg/g carbon (Guisti et al.,
1974).
Hydroxyl radicals react with methanol in aqueous solution at a reaction rate of 1.60 x 10-12
cm3/molecule?sec (Wallington et al., 1988).
Complete combustion in air produces carbon dioxide and water. The stoichiometric equation for
this oxidation reaction is:
2CH4O + 3O2 → 2CO2 + 4H2O
storage
Methanol should
be used only in areas free of ignition sources, and quantities greater than 1 liter
should be stored in tightly sealed metal containers in areas separate from oxidizers.
Purification Methods
Almost all methanol is now obtained synthetically. Likely impurities are water, acetone, formaldehyde, ethanol, methyl formate and traces of dimethyl ether, methylal, methyl acetate, acetaldehyde, carbon dioxide and ammonia. Most of the water (down to about 0.01%) can be removed by fractional distillation. Drying with CaO is unnecessary and wasteful. Anhydrous methanol can be obtained from "absolute" material by passage through Linde type 4A molecular sieves, or by drying with CaH2, CaSO4, or with just a little more sodium than required to react with the water present, in all cases the methanol is then distilled. Two treatments with sodium reduces the water content to about 5 x 10-5%. [Friedman et al. J Am Chem Soc 83 4050 1961.] Lund and Bjerrum [Chem Ber 64 210 1931] warmed clean dry magnesium turnings (5g) and iodine (0.5g) with 50-75mL of "absolute" methanol in a flask until the iodine disappeared and all the magnesium was converted to the methoxide. Up to 1L of methanol was added and, after refluxing for 2-3hours, it was distilled off, excluding moisture from the system. Redistillation from tribromobenzoic acid removes basic impurities and traces of magnesium oxides, and leaves conductivity-quality material. The method of Hartley and Raikes [J Chem Soc 127 524 1925] gives a slightly better product. This consists of an initial fractional distillation, followed by distillation from aluminium methoxide, and then ammonia and other volatile impurities are removed by refluxing for 6hours with freshly dehydrated CuSO4 (2g/L) while dry air is passed through: the methanol is finally distilled. (The aluminium methoxide is prepared by warming with aluminium amalgam (3g/L) until all the aluminium has reacted. The amalgam is obtained by warming pieces of sheet aluminium with a solution of HgCl2 in dry methanol.) This treatment also removes aldehydes. If acetone is present in the methanol, it is usually removed prior to drying. Bates, Mullaly and Hartley [J Chem Soc 401 1923] dissolved 25g of iodine in 1L of methanol and then poured the solution, with constant stirring, into 500mL of M NaOH. Addition of 150mL of water precipitated iodoform. The solution was allowed to stand overnight, filtered, then boiled under reflux until the odour of iodoform disappeared, and fractionally distilled. (This treatment also removes formaldehyde.) Morton and Mark [Ind Eng Chem (Anal Edn) 6 151 1934] refluxed methanol (1L) with furfural (50mL) and 10% NaOH solution (120mL) for 6-12hours, the refluxing resin carries down with it the acetone and other carbonyl-containing impurities. The alcohol was then fractionally distilled. Evers and Knox [J Am Chem Soc 73 1739 1951], after refluxing 4.5L of methanol for 24hours with 50g of magnesium, distilled off 4L of it, which they then refluxed with AgNO3 for 24hours in the absence of moisture or CO2. The methanol was again distilled, shaken for 24hours with activated alumina before being filtered through a glass sinter and distilled under nitrogen in an all-glass still. Material suitable for conductivity work was obtained. Variations of the above methods have also been used. For example, a sodium hydroxide solution containing iodine has been added to methanol and, after standing for 1day, the solution has been poured slowly into about a quarter of its volume of 10% AgNO3, shaken for several hours, then distilled. Sulfanilic acid has been used instead of tribromobenzoic acid in Lund and Bjerrum's method. A solution of 15g of magnesium in 500mL of methanol has been heated under reflux, under nitrogen, with hydroquinone (30g), before degassing and distilling the methanol, which was subsequently stored with magnesium (2g) and hydroquinone (4g per 100mL). Refluxing for about 12hours removes the bulk of the formaldehyde from methanol: further purification has been obtained by subsequent distillation, refluxing for 12hours with dinitrophenylhydrazine (5g) and H2SO4 (2g/L), and again fractionally distilling. [Beilstein 1 IV 1227.]
Toxics Screening Level
The Initial Threshold Screening Level (ITSL) is 20,000μg/m3 with 4-hour averaging time.
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