Introduction

Methanol is the simplest fatty alcohol. It is a colorless, flammable, irritating liquid with a boiling point of 64.7°C, a melting point of -93.90°C, and a relative density of 0.7913. Soluble in water and most organic solvents. Its severe toxicity can damage the optic nerve. Once swallowed, it can make the eyes blind and even cause death.
Methanol has the general properties of a primary aliphatic alcohol. The three hydrogen atoms on a carbon atom with a hydroxyl group can be oxidized, orderly generating formaldehyde, formic acid, and carbon dioxide. Therefore, it is largely used in the synthesis of formaldehyde. Methanol is easily converted into important organic synthesis intermediates such as methyl carboxylate, methyl chloride and methylamine, and it is also applied as important organic solvents, extraction agents and alcohol denaturants.

Chemical Properties

Methanol is a clear, colorless liquid with a characteristic pungent odor (NTP NIEHS web accessed 2/16/2013). The air odor threshold has been reported as 1500 ppm (approximately 2000mg/m3), much higher than the occupational guidelines.

Methanol (methyl alcohol; wood alcohol) is used extensively as a solvent for lacquers, paints, varnishes, cements, inks, dyes, plastics, and various industrial coatings. Large quantities are used in the production of formaldehyde and other chemical derivatives such as acetic acid, methyl halides and terephthalate, methyl methacrylate, and methylamines. Methanol is also used as a gasoline additive, as a component of lacquer thinners, in antifreeze preparations of the “nonpermanent” type, and in canned heating preparations of jellied alcohol. It is also used in duplicating fluid, in paint removers, and as a cleaning agent. The potential for methanol as a future alternative for gasoline indicates that the use of this chemical will most likely increase rather than decrease. At room temperature, methanol is a colorless liquid with a pungent odor. It is relatively volatile, with a vapor pressure of 96 mmHg and a vapor density of 1.11. It is miscible with water and soluble with other organic solvents. It is found in nature as a fermentation product of wood and as a constituent of some fruits and vegetables.

Uses

Methanol is an important chemical raw material for fine chemicals. Its carbonylation at 3.5 MPa and 180-200° C in the presence of catalyst can produce acetic acid and further produce acetic anhydride. It reacts with syngas to prepare vinyl acetate in the presence of catalyst; reacts with isobutylene to produce tert-butyl methyl ether; prepare dimethyl oxalate through oxidization and carbonylation, and a further hydrogenation to produce ethylene glycol; reacts with toluene under catalyst and simultaneous oxidization to produce phenylethyl alcohol. It can be used as a good solvent, as a pesticide raw material, as an antifreeze agent, as a fuel and fuel additive (this is receiving increasing attention in environmental protection field). It is the main raw material in the preparation of formaldehyde, the raw material in medicine and spices production, a solvent in dyes and paint industries, the raw material in preparation of methanol single cell protein and synthesis of methyl ester.

Methanol poisoning and First Aid Measures

Pathogenesis
First, methanol has a cumulative effect and is oxidized in the body into more toxic formaldehyde and formic acid. Methanol and its oxides directly damage the tissues, causing cerebral edema, meningeal hemorrhage, optic nerve and retinal atrophy, pulmonary congestion and edema, and hepatic and renal turbid swelling.
Second, methanol and its oxides cause blood circulation disorder, coenzyme system obstacles in vivo, resulting in lack of oxygen supply to the brain cortical cells, metabolic disorders, and related neurological and psychiatric symptoms.
Third, methanol oxidation products combine with the iron in the cytochrome oxidase, which inhibits the intracellular oxidation process thus causing metabolic disorders, acidosis along with organic acid accumulation in the body, and nerve cells impair.

Treatment

• Keep away from the methanol dispersion area, excrete methanol from the body.
  Antidote: Ethanol is an antidote to methanol poisoning. Ethanol can prevent methanol’s oxidation and promote its emission. Prepare 5% ethanol solution using 10% glucose solution, and drip slowly intravenously.
• Maintain electrolyte balance: maintain respiratory and circulatory function, provide with a large number of Vitamin B.
  Treatment of acidosis: Administrate timely sodium bicarbonate solution or sodium lactate solution based on blood gas analysis, carbon dioxide binding force measurement and clinical performance.
• Prevent cerebral edemas actively, reduce intracranial pressure, improve fundus blood circulation, and prevent optic neuropathy if needed.
• Inject intravenously cytochrome C, polar fluid to restore cytochrome oxidase function.
• Control mental state by applying diazepam, perphenazine and the like.

Symptoms and treatments:

Reactivities of Methanol

Methanol is the simplest aliphatic alcohol. It contains only one carbon atom. Unlike higher alcohols, it cannot form an olefin through dehydration. However, it can undergo other typical reactions of aliphatic alcohols involving cleavage of a C-H bond or O-H bond and displacement of the -OH group. Table 1 summarizes the reactions of methanol, which are classified in terms of their mechanisms. Examples of the reactions and products are given.

Homolytic dissociation energies of the C-O and O-H bonds in methanol are relatively high. Catalysts are often used to activate the bonds and to increase the selectivity to desired products.

Production

Methanol is prepared by pressure heating with carbon monoxide and hydrogen in the presence of a catalyst:

If the conditions are strictly controlled, the yield can reach 100% and the purity can reach 99%. Methane is mixed with oxygen (9:1, V/V) and methanol is obtained through a copper tube under heating and pressure:

Toxicity evaluation

ADI is limited to GMP (FAO/WHO, 2001).
Toxic, can cause blindness.
LD50: 5628 mg/kg (rat, oral).

from The National Institute for Occupational Safety and Health – NIOSH

Methanol gasoline

Methanol gasoline refers to the M series mixture fuel made of addition of methanol to the gasoline and formulated using methanol fuel solvent. Among them, M15 (add 15% methanol in gasoline) clean methanol gasoline is used as vehicle fuel, respectively, used in a variety of gasoline engines. It can be applied to substitute the finished gasoline without changing the existing engine structure, and can also be mixed with refined oil. The methanol mixed fuel has excellent thermal efficiency, power, start-up and being economical. It is also characterized by lowering the emissions, saving oil and being safe and convenient. Methanol gasoline types of M35, M15, M20, M50, N85 and M100 with different blend ratios have been developed around the world according to the conditions of different countries. At present, the commercial methanol is mainly M85 (85% methanol + 15% gasoline) and M100 with M100 performance being better than M85 and having greater environmental advantages.

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.

Chemical Properties

Methanol is a clear, water-white liquid with a mild odor at ambient temperatures.The air odor threshold for methanol has been reported as 100 ppm . Others have reported that 2000 or 5900 ppm methanol is barely detectable .

Physical properties

Clear, colorless liquid with a characteristic alcoholic odor. Odor threshold concentrations ranged from 8.5 ppb_v (Nagata and Takeuchi, 1990) to 100.0 ppm_v (Leonardos et al., 1969). Experimentally determined detection and recognition odor threshold concentrations were 5.5 mg/m³ (4.2 ppm_v) and 69 mg/m³ (53 ppm_v), 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.

Uses

Methanol has numerous uses. Its main use is in the production of formaldehyde, whichconsumes approximately 40% of methanol supplies. Methanolis a common organic solvent found in many products including deicers (windshield wiperfl uid), antifreezes, correction fl uid, fuel additives, paints, and other coatings. A number ofindustrial chemicals use methanol in their production. Among these are methyl methacrylateand dimethyl terephthalate. Methanol is used to convert methylacrylamide sulfate to methylmethacrylate and ammonium hydrogen sulfate (NH4HSO4):
Methanol is used in making the ester dimethyl terephthalate from mixtures ofxylene of toluene. Dimethyl terephthalate is used in the manufacture of polyesters and plastics.
Methanol is used as a fuel additive. The common gasoline additive HEET is pure methanoland is used as a gas-line antifreeze and water remover. Methanol is used as a fuel in camp stoves and small heating devices. It is used to fuel the small engines used in models (airplanes,boats). In the early history of automobiles,methanol was a common fuel. The availability of cheap gasoline replaced methanol in the1920s, but it is receiving renewed interest as an alternative fuel as the demand and cost of oilincrease and oil supplies become uncertain. Methanol can be produced from coal and biomass.Methanol has a higher octane rating and generally lower pollutant emissions compared togasoline. The relatively low flame temperature means that fewer nitrogen oxides are producedby methanol than by ethanol. One large disadvantage of methanol is that it has a lower energydensity than gasoline. Using equivalent volumes of gasoline and methanol, methanol givesabout half the mileage of gasoline. Another problem with methanol is its low vapor pressure,resulting in starting problems on cold days. This problem can be mitigated by using a blendof 85% methanol and 15% gasoline. This mixture is called M85 and is similar to E85 ethanol(see Ethyl Alcohol).

Uses

high purity grade for ICP-MS detection

Uses

Methanol is used in the production offormaldehyde, acetic acid, methyl tert-butylether, and many chemical intermediates; asan octane improver (in oxinol); and as apossible alternative to diesel fuel; being anexcellent polar solvent, it is widely used as acommon laboratory chemical and as a methylating reagent.

Uses

Methylalcohol, CH30H, also known as methanol or wood alcohol, is a colorless, toxic, flammable liquid with a boiling point of 64.6 °C(147 °F). The principal toxic effect is on the nervous system,particularly the retinae. Methyl alcoholis miscible in all proportions with water,ethyl alcohol, and ether. It burns with a light blue flame producing water and carbon dioxide. This vapor forms an explosive mixture(6.0 to 36.5% by volume) with air. Methyl alcohol is an important inexpensive raw material that is synthetically produced for the organic chemical industry. Nearly half of the methyl alcohol manufactured is used in the production of formaldehyde. Other uses of methyl alcohol are as an antifreeze and fuel for automobiles and as an intermediate in the production of synthetic protein.

Uses

Industrial solvent. Raw material for making formaldehyde and methyl esters of organic and inorganic acids. Antifreeze for automotive radiators and air brakes; ingredient of gasoline and diesel oil antifreezes. Octane booster in gasoline. As fuel for picnic stoves and soldering torches. Extractant for animal and vegetable oils. To denature ethanol. Softening agent for pyroxylin plastics. Solvent and solvent adjuvant for polymers. Solvent in the manufacture of cholesterol, streptomycin, vitamins, hormones, and other pharmaceuticals.

Definition

ChEBI: Methanol is the primary alcohol that is the simplest aliphatic alcohol, comprising a methyl and an alcohol group. It has a role as an amphiprotic solvent, a fuel, a human metabolite, an Escherichia coli metabolite, a mouse metabolite and a Mycoplasma genitalium metabolite. It is an alkyl alcohol, a one-carbon compound, a volatile organic compound and a primary alcohol. It is a conjugate acid of a methoxide.

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.

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 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 exploded when Methanol was disturbed [J. Am. Chem. Soc. 52:2391. 1930]. P4O6 reacts violently with Methanol. (Thorpe, T. E. et al., J. Chem. Soc., 1890, 57, 569-573). Ethanol or Methanol can ignite on contact with a platinum-black catalyst. (Urben 1794).

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

The acute toxicity of methanol by ingestion, inhalation, and skin contact is low. Ingestion of methanol or inhalation of high concentrations can produce headache, drowsiness, blurred vision, nausea, vomiting, blindness, and death. In humans, 60 to 250 mL is reported to be a lethal dose. Prolonged or repeated skin contact can cause irritation and inflammation; methanol can be absorbed through the skin in toxic amounts. Contact of methanol with the eyes can cause irritation and burns. Methanol is not considered to have adequate warning properties.
Methanol has not been found to be carcinogenic in humans. Information available is insufficient to characterize the reproductive hazard presented by methanol. In animal tests, the compound produced developmental effects only at levels that were maternally toxic; hence, it is not considered to be a highly significant hazard to the fetus. Tests in bacterial or mammalian cell cultures demonstrate no mutagenic activity