Methyl Acetate
Methyl acetate, also known as MeOAc, acetic acid methyl ester or methyl ethanoate, is a carboxylate ester with the formula CH3COOCH3. Methyl acetate is a flammable liquid with a characteristically pleasant smell reminiscent of some glues and nail polish removers. Methyl acetate is occasionally used as a solvent, being weakly polar and lipophilic, but its close relative ethyl acetate is a more common solvent being less toxic and less soluble in water. Methyl acetate has a solubility of 25% in water at room temperature. At elevated temperature its solubility in water is much higher. Methyl acetate is not stable in the presence of strong aqueous bases or aqueous acids. Methyl acetate is not considered a VOC in the USA.
Preparation and reactions of Methyl acetate
Methyl acetate is produced industrially via the carbonylation of methanol as a byproduct of the production of acetic acid.[6] Methyl acetate also arises by esterification of acetic acid with methanol in the presence of strong acids such as sulfuric acid; this production process is famous because of Eastman Kodak's intensified process using a reactive distillation.
Reactions of Methyl acetate
In the presence of strong bases such as sodium hydroxide or strong acids such as hydrochloric acid or sulfuric acid it is hydrolyzed back into methanol and acetic acid, especially at elevated temperature. The conversion of methyl acetate back into its components, by an acid, is a first-order reaction with respect to the ester. The reaction of methyl acetate and a base, for example sodium hydroxide, is a second-order reaction with respect to both reactants.
Methyl acetate is a Lewis base that forms 1:1 adducts with a variety of Lewis acids. It is classified as a hard base and is a base in the ECW model with EB =1.63 and CB = 0.95.
Applications of Methyl acetate
A major use of methyl acetate is as a volatile low toxicity solvent in glues, paints, and nail polish removers.
Acetic anhydride is produced by carbonylation of methyl acetate in a process that was inspired by the Monsanto acetic acid synthesis.
General description of Methyl acetate
Methyl acetate (MA) is an aliphatic ester that can be prepared via carbonylation of dimethyl ether over zeolites.[7] Methyl acetate is formed as a by-product during the preparation of polyvinyl alcohol from acetic acid and methanol.[8]
Application of Methyl acetate
Methyl acetate may be used for the preparation of fatty acid methyl esters and triacetin from rapeseed oil via non-catalytic trans-esterification reaction under super-critical conditions.[9]
Packaging of Methyl acetate
1, 2 L in Sure/Seal™
100 mL in Sure/Seal
Methyl acetate appears as a clear colorless liquid with a fragrant odor. Moderately toxic. Flash point 14°F. Vapors heavier than air.
Methyl acetate is an acetate ester resulting from the formal condensation of acetic acid with methanol. A low-boiling (57 ℃) colourless, flammable liquid, it is used as a solvent for many resins and oils. It has a role as a polar aprotic solvent, a fragrance and an EC 3.4.19.3 (pyroglutamyl-peptidase I) inhibitor. It is an acetate ester, a methyl ester and a volatile organic compound.
Methyl acetate is a waste chemical stream constituent which may be subjected to ultimate disposal by controlled incineration.
The following wastewater treatment technologies have been investigated for methyl acetate: Concentration process: Reverse osmosis.
EXCESS METHYL ACETATE IN WASTE GASES CAN BE REMOVED BY CATALYTIC OXIDATION.
Absorption, Distribution and Excretion of Methyl acetate
After oral administration to rabbits, methyl acetate was hydrolysed to methanol and acetic acid. The animals received a dosage of 20 mL/kg bw of a 5% aqueous solution (1,000 mg/kg). Methanol concentration was analysed in the blood from 30 minutes after application up to 5 hours. Methyl acetate could not be detected in any sample whereas methanol was found in blood and urine already after 30 min. Peak concentrations of methanol in the blood were measured after 3 hours and amounted to 0.573 mg/mL. Following oral application methyl acetate is hydrolysed in the gut. Therefore, in blood and urine only methanol and acetic acid were found, not methyl acetate. Similarly, after inhalation exposure in blood and urine only the products of hydrolysis were detectable.
After oral exposure methyl acetate is partially cleaved in the gastrointestinal tract into methanol and acetic acid by esterases of the gastric mucosa. The ester is furthermore hydrolysed by esterases of the blood. Similarly, after inhalation exposure of rats to a concentration of 2,000 ppm (6,040 mg/cu m) blood concentrations less than 4.6 mg/L were determined. ... Inhalation exposure at saturation conditions results in the occurrence of methyl acetate in blood.
Biotransformation of methyl acetate takes place by rapid hydrolysis of the compound into methanol and acetic acid by the nonspecific carboxylic esterases in the blood and tissues.
With human subjects /it has been shown/ that metabolic hydrolysis of methyl acetate to methanol and acetic acid proceeds directly proportional to exposure level.
Biological Half-Life of Methyl acetate
For the in vitro hydrolysis of methyl acetate in blood of rats /a/ half-life of 2-3 hr was determined indicating a rapid hydrolysis in the blood.
For the in vitro hydrolysis of methyl acetate in blood of humans, /a/ half-life of about 4 hr was determined.
Commonly sold in combination with methanol in an 80/20 methyl acetate/methanol by-product blend
Overview of Methyl acetate
IDENTIFICATION: Methyl acetate is a colorless volatile liquid. It has a pleasant fruity odor. The vapor is heavier than air. It will dissolve in water. USE: Methyl acetate is used in paint remover compounds and solvents. It is used to make other chemicals. It is used as an imitation fruit flavoring. EXPOSURE: Workers in the paint industry and paper mills may be exposed to methyl acetate. People may be exposed to methyl acetate by breathing in air when using paint remover or eating foods containing methyl acetate as a flavor ingredient. Methyl acetate occurs naturally in mint, fungus, Kiwi fruit, grapes, and bananas. If methyl acetate is released to the environment, it will break down in air. It will move down through soil. It will volatilize from soil and water. Methyl acetate is very soluble in water. It appears to be rapidly broken down by microorganisms in soil and water. It does not build up in aquatic organisms. RISK: Methyl acetate is absorbed by the respiratory system and by the skin. In the body, methyl acetate is rapidly converted to methanol. Eye irritation has been reported in furniture polishers exposed to paint thinners containing methyl acetate and other solvents. Recurrent dizziness, headaches, fatigue, faintness, staggering and blindness occurred in a worker exposed to vapors of methyl acetate in an enclosed space. Very high exposure may result in unconsciousness and death. These effects are consistent with the toxic effects of methanol. Eye irritation and skin damage have been observed in laboratory animals following application of methyl acetate to the eyes or skin. Methyl acetate has not been tested for cancer, developmental or reproductive effects in laboratory animals. The potential for methyl acetate to cause cancer in humans has not been assessed by the U.S. EPA IRIS program, the International Agency for Research on Cancer, or the U.S. National Toxicology Program 12th Report on Carcinogens. Storage Conditions of Methyl acetate
Store in a flammable liquid storage area or approved cabinet away from ignition sources and corrosive and reactive materials. ... Methyl acetate must be stored to avoid contact with strong oxidizers (such as chlorine, bromine, and fluorine) and strong acids (such as hydrochloric, sulfuric, and nitric), since violent reactions occur. Store in tightly closed containers in a cool, well-ventilated area away from strong alkalis and nitrates. Sources of ignition, such as smoking and open flames, are prohibited where methyl acetate is used, handled or stored in a manner that could create a potential fire or explosion hazard. Use only nonsparking tools and equipment, especially when opening and closing containers of methyl acetate.
Conditions for safe storage, including any incompatibilities: Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Moisture sensitive.
Reactivity Profile of Methyl acetate
METHYL ACETATE presents a fire or explosion hazard when exposed to strong oxidizing agents. Emits irritating fumes and acrid smoke when heated to decomposition, [Lewis, 3rd ed., 1993, p. 826]. Its reactivity is consistent with other compounds of the ester group.
For more DOT Emergency Guidelines (Complete) data for METHYL ACETATE (8 total), please visit the HSDB record page.
This action promulgates standards of performance for equipment leaks of Volatile Organic Compounds (VOC) in the Synthetic Organic Chemical Manufacturing Industry (SOCMI). The intended effect of these standards is to require all newly constructed, modified, and reconstructed SOCMI process units to use the best demonstrated system of continuous emission reduction for equipment leaks of VOC, considering costs, non air quality health and environmental impact and energy requirements. Methyl acetate is produced, as an intermediate or final product, by process units covered under this subpart.
Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. Methyl acetate is included on this list. Effective date: 1/26/94; Sunset date: 6/30/98.
Methyl acetate is a food additive permitted for direct addition to food for human consumption as a synthetic flavoring substance and adjuvant in accordance with the following conditions: a) they are used in the minimum quantity required to produce their intended effect, and otherwise in accordance with all the principles of good manufacturing practice, and 2) they consist of one or more of the following, used alone or in combination with flavoring substances and adjuvants generally recognized as safe in food, prior-sanctioned for such use, or regulated by an appropriate section in this part.
Methyl acetate is an indirect food additive for use only as a component of adhesives.
At high concentrations, methyl acetate may cause mild to severe methanol intoxication form ingestion, inhalation, or possible skin contact. The vapor is mildly irritant to the eyes and respiratory system and at high concentrations can cause CNS depression.
IDENTIFICATION AND USE: Methyl Acetate is a colorless, volatile liquid, which is used as a solvent for nitrocellulose, acetylcellulose; in many resins and oils and in the manufacture of artificial leather. It is also used in paint remover compounds, lacquer solvent, intermediate, and synthetic flavoring. HUMAN EXPOSURE AND TOXICITY: The vapor is mild irritant to the eyes and respiratory system and at high concentrations can cause CNS depression. Accidental human exposure to methyl acetate vapor for 45 minutes resulted in severe headache and somnolence lasting about 6 hr. In another case report, a teenage girl experienced acute blindness following inhalation of vapor from lacquer thinner. It was determined that methanol and methyl acetate vapors caused optic neuropathy that led to the blindness. At high concentrations, methyl acetate may cause mild to severe methanol intoxication from ingestion, inhalation, or possible skin contact. ANIMAL STUDIES: Inhalation exposure of 4 rats to a saturated atmosphere of methyl acetate (in 25 L bottles) induced narcotic effects in the animals after 10 to 20 min. After decapitation at this time-point concentrations of 70-80 mg methyl acetate/100 mL were found in the blood. Similar experiments with inhalation exposure to methanol showed that the narcotic effects are mainly induced by methyl acetate. Cats exposed to 10,560 ppm methyl acetate vapor suffered from irritation of the eyes and salivation. Rats were exposed (at 10,000 ppm in ambient air) to a thinner containing methyl acetate (12.6%) in a plastic container for 10 min at 10 min intervals (2 times/day, 6 days/wk, for 12-14 mo). Body weight gain was suppressed compared to controls. Electron microscopic exam of slices of the cerebral cortex showed increased abnormal cristae of mitochondria in the neurons and axons and increased number of endoplasmic reticula and ribosomes and dilated Golgi apparatus in the neurons. Increased lysosomes and lipid materials were observed in neurons, suggesting a degenerative process. Methyl acetate did not produce an increase in revertants in Salmonella typhimurium strains TA 98, TA 100, TA 1535, TA 1537 and TA 1538, and Escherichia coli WP2uvrA, in the absence or presence of metabolic activation. Methyl acetate was tested up to 5,000 ug/plate. Negative results were obtained in a study using Salmonella typhimurium strains TA97, TA98, TA100, TA1535 and TA1538 with or without metabolic activation system, when tested up to 10,000 ug/plate. This study employed a 20-minute preincubation period. Biotransformation of methyl acetate takes place by rapid hydrolysis of the compound into methanol and acetic acid by the nonspecific carboxylic esterases in the blood and tissues.
/HUMAN EXPOSURE STUDIES/ Respiratory uptake was investigated for 10 polar organic solvents with high blood/air partition coefficients (lambda(blood/air)): ethyl acetate (lambda(blood/air), 77), methyl iso-butyl ketone (90), methyl acetate (90), methyl propyl ketone (150), acetone (245), iso-pentyl alcohol (381), iso-propyl alcohol (848), methyl alcohol (2590), ethylene glycol monobutyl ether (EGBE, 7970), and propylene glycol monomethyl ether (PGME, 12380). Test-air concentrations (Cinh) were 25 to 200 ppm. Four healthy male volunteers inhaled the test air for 10 min at rest and then room air for 5 min. The percentage of solvent in the end-exhaled air and in the mixed-exhaled air increased after the start of the test-air respiration, and reached a quasi-steady-state level within a few min. The speeds of these increases at the start of the test-air respiration became lower as lambda(blood/air) increased. The mean uptakes (U) for the last five min of the test air respiration were 67.3, 52.9, 60.4, 53.0, 52.6, 63.0, 60.3, 60.8, 79.7, and 81.3%, respectively, for ethyl acetate, methyl iso-butyl ketone, methyl acetate, methyl propyl ketone, acetone, iso-pentyl alcohol, iso-propyl alcohol, methyl alcohol, EGBE and PGME. Thus, U values of the alcohols were higher than those of the ketones and lower than the glycol ethers. The overall view, except for esters, showed that U increased with lambda(water/air) increases. This tendency can be explained by a hypothesis that solvent absorbed in the mucus layer of the respiratory tract is removed by the bronchial blood circulation. U values of ethyl acetate and methyl acetate were higher than those of methyl iso-butyl ketone and methyl propyl ketone, though the lambda(blood/air) values of these esters were nearly equal to those of the ketones. For the respiration of the esters, their metabolites, ethyl alcohol and methyl alcohol, were detected in the exhaled air. The exhalation percentage of the metabolites increased after the start of test-air respiration and reached a quasi-steady-state level of 2 and 3%, respectively, by the 5th min. These data suggest that removal of the solvent via metabolism in the wall tissue of the respiratory tract plays an important role for the esters.
Women working in a shoe-factory suffered from eye irritation, visual disorders, CNS symptoms, difficulties of breathing and heart trouble and identified a liquid mixture of methylformate, ethylformate, ethyl acetate and methyl acetate.
Acute Exposure/ Inhalation exposure of 4 rats to a probably saturated atmosphere of methyl acetate (in 25 L bottles) induced /CNS depressant/ effects in the animals after 10 to 20 min. After decapitation at this time-point concentrations of 70-80 mg methyl acetate/100 mL were found in the blood. Similar experiments with inhalation exposure to methanol showed that the narcotic effects are mainly induced by methyl acetate.
Acute Exposure/ Cats exposed to /inhalation of methyl acetate/ 53,790 ppm for 14-18 min /showed/ irritation, salivation, dyspnea, convulsions in 50%, /CNS depression/, lethal in 1-9 min, later with diffuse pulmonary edema. 34,980 ppm for 29-30 min /produced/ irritation, salivation, dyspnea, convulsions in 50%, narcosis, histology: lateral emphysema or edema. /From table/
Acute Exposure/ Cats exposed to /inhalation of methyl acetate/ 18480 ppm for 4 to 4.5 hr showed eye irritation, dyspnea, vomiting and convulsions in 50%, /CNS depression/, slow recovery; at 9900 ppm for 10 hr, eye irritation, salivation, somnolence, recovery;at 5000 ppm for 20 min, eye irritation and salivation. /From table/
Environmental Fate/Exposure Summary
Methyl acetate's production and use as a solvent for nitrocellulose, acetylcellulose, resins and oils, in the manufacture of artificial leather; as a catalyst for the biodegradation of organic materials; as a flavoring agent useful in rum, brandy, whiskey; and as a chemical intermediate may result in its release to the environment through various waste streams. Methyl acetate occurs naturally in mint, fungus, grapes, bananas and coffee. If released to air, a vapor pressure of 216.2 mm Hg at 25 °C indicates methyl acetate will exist solely as a vapor in the atmosphere. Vapor-phase methyl acetate will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 41 days. Methyl acetate does not contain chromophores that absorb at wavelengths >290 nm and, therefore, is not expected to be susceptible to direct photolysis by sunlight. If released to soil, methyl acetate is expected to have very high mobility based upon an estimated Koc of 9.1. Volatilization from moist soil surfaces is expected to be an important fate process based upon a measured Henry's Law constant of 1.15X10-4 atm-cu m/mole. Methyl acetate may volatilize from dry soil surfaces based upon its vapor pressure. Methyl acetate achieved >70% after 28 days in an OECD 301D Closed bottle test, suggesting that biodegradation is an important environmental fate process in soil and water. If released into water, methyl acetate is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 5 hours and 5 days, respectively. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis half-lives for methyl acetate were 1.7 years and 63 days at pH values of 7 and 8. Occupational exposure to methyl acetate may occur through inhalation and dermal contact with this compound at workplaces where methyl acetate is produced or used. Monitoring and use data indicate that the general population may be exposed to methyl acetate via inhalation of ambient air and ingestion of food and dermal contact with consumer products containing methyl acetate.
Methyl acetate may be released to the environment from natural sources. It has been detected as a volatile constituent of nectarines(1,3) and Kiwi fruit flowers(2). Methyl acetate occurs naturally in mint, fungus, grapes and bananas(3).
Methyl acetate's production and use as a solvent for nitrocellulose, acetylcellulose, resins and oils, in the manufacture of artificial leather(1); as a catalyst for the biodegradation of organic materials(2); as a flavoring agent useful in rum, brandy, whiskey(3); and as a chemical intermediate(4) may result in its release to the environment through various waste streams(SRC).
TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 9.1(SRC), determined from a log Kow of 0.18(2) and a regression-derived equation(3), indicates that methyl acetate is expected to have very high mobility in soil(SRC). Volatilization of methyl acetate from moist soil surfaces is expected to be an important fate process(SRC) given a measured Henry's Law constant of 1.15X10-4 atm-cu m/mole(4). Methyl acetate is expected to volatilize from dry soil surfaces(SRC) based upon an measured vapor pressure of 216.2 mm Hg at 25 °C(5). Methyl acetate achieved >70% after 28 days in an OECD 301D Closed bottle test(6), suggesting that biodegradation is an important environmental fate process in soil(SRC).
AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 9.1(SRC), determined from a log Kow of 0.18(2) and a regression-derived equation(3), indicates that methyl acetate is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(4) based upon a measured Henry's Law constant of 1.15X10-4 atm-cu m/mole(5). Using this Henry's Law constant and an estimation method(4), volatilization half-lives for a model river and model lake are 5 hours and 5 days, respectively(SRC). According to a classification scheme(6), an estimated BCF of 3(SRC), from its log Kow(2) and a regression-derived equation(3), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Methyl acetate achieved >70% after 28 days in an OECD 301D Closed bottle test(7), suggesting that biodegradation is an important environmental fate process in water(SRC).
ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), methyl acetate, which has a vapor pressure of 216.2 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase methyl acetate is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 41 days(SRC), calculated from its rate constant of 2.6X10-13 cu cm/molecule-sec at 25 °C(3). Methyl acetate does not contain chromophores that absorb at wavelengths >290 nm(4) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).
AEROBIC: Methyl acetate achieved >70% after 28 days in an OECD 301D Closed bottle test(1). Methyl acetate reached > 95% degradation in a 5 day BOD test(2).
ANAEROBIC: Methyl acetate is listed as a compound that should undergo ultimate anaerobic biodegradation in industrial wastewater(1). Methyl acetate achieved 96% anaerobic utilization efficiency after a 90 day acclimation period in completely mixed reactors(2). Methyl acetate, present at 50 ppm C, was completely degraded in anaerobic aquifer slurries at a rate of 16.6 ppm C/day and an acclimation period of 0 to 15 days(3).
Alcaligenes faecalis, isolated from activated sludge, was found to oxidize methyl acetate after a short lag period(1).
Environmental Abiotic Degradation of Methyl acetate
The rate constant for the vapor-phase reaction of methyl acetate with photochemically-produced hydroxyl radicals has been estimated as 2.6X10-13 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 41 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). A base-catalyzed second-order hydrolysis rate constant of 1.3X10-1 L/mole-sec(SRC) was estimated using a structure estimation method(2); this corresponds to half-lives of 1.7 years and 63 days at pH values of 7 and 8, respectively(2). Methyl acetate does not contain chromophores that absorb at wavelengths >290 nm(3) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).
An estimated BCF of 3.2 was calculated in fish for methyl acetate(SRC), using a log Kow of 0.18(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).
The Koc of methyl acetate is estimated as 9.1(SRC), using a log Kow of 0.18(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that methyl acetate is expected to have very high mobility in soil(SRC).
The Henry's Law constant for methyl acetate is 1.15X10-4 atm-cu m/mole(1). This Henry's Law constant indicates that methyl acetate is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 5 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 5 days(SRC). Methyl acetate's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). The potential for volatilization of methyl acetate from dry soil surfaces may exist(SRC) based upon a vapor pressure of 216.2 mm Hg(3).
Methyl acetate was detected, not quantified, in the drinking water from multiple sources in the United States(1).
Effluent Concentrations of Methyl acetate
Methyl acetate was detected in the waste stream of industrial waste after deep-well injection between 1971 to 1972 at <0.5 mg/L DOC(1). Methyl acetate was detected, not quantified, in the effluent gas from refuse waste obtained from a food center(2). Methyl acetate was detected in active blower exhaust between October and November 1989 at a concentration of 144 ug/cu m from a wastewater treatment sludge/wood chip compost pile located at the Peninsula Composting Facility(3). Methyl acetate was also detected in the biowaste during the aerobic composting process (ACP) at a concentration of 24 mg/cu m(4). Methyl acetate was detected, not quantified, as a volatile organic compound in kitchen waste, kitchen waste exudate, stored food exudate(5), and in garden waste exudate(6). Methyl acetate was also detected in 4 out of 4 biodegradable waste samples collected from household waste at concentrations ranging from 0.1 to 1 mg/cu m and in 5 out of 7 mixed kitchen waste samples at a concentration of <0.1 mg/cu m(7). Methyl acetate was detected as an emission from the production of RDX at the Holston Army Ammunition Plant, TN at an emission rate of 733 lbs/day(8).
Atmospheric Concentrations
URBAN/SUBURBAN: Methyl acetate was detected as a volatile organic compound collected from UK cities at 0.0018%(1). Methyl acetate was detected in the emissions collected from the Gubrist highway tunnel, Switzerland, in 2004; the emission factor was reported to be 0.03 mg/kg(2).
INDOOR: Methyl acetate was detected from the emissions from carpet with a PVC backing in an environmental chamber; the emission rate was 0.08 mg/cu m in a 24 hour time period(1). Methyl acetate was also detected, not quantified, from the emissions from furniture coatings in an environmental chamber(2). Methyl acetate was detected, not quantified, in household consumer products, specifically liquid all purpose adhesive(3).
RURAL/REMOTE: Methyl acetate was detected, not quantified, in forest air samples collected from the Eggegbirge in North Rhine-Westfalia, Germany(1).
SOURCE DOMINATED: Methyl acetate was detected, not quantified, in the air of the industrialized Kanawha Valley, WV in 1977(1).
Methyl acetate was reported in fresh grapefruit juice at a concentration of 0.026 ppm(1). Methyl acetate was detected in the emissions of corn silage, alfalfa silage, cereal silage and almond shells at concentrations of 3.14, 6.15, 0.29 and 0.10 nL/L(2). Methyl acetate was detected, not quantified, as a volatile component in floured chickpea seed(3), chicken meat(4), Cabernet Sauvignon wine from Napa Valley, CA(5). Methyl acetate is reported as found in coffee(6).
Methyl acetate was reported in the volatile fraction from Kiwi Fruit flowers (Actinidia chinensis) at 0.57% of the total area(1).
Methyl acetate was detected, not quantified in cow milk(1).
Methyl acetate was identified as a solvent in a sample of printer's inks at a concentration of 0.1% (W/W)(1).
According to the 2012 TSCA Inventory Update Reporting data, the number of persons reasonably likely to be exposed in the industrial manufacturing, processing, and use of methyl acetate is 5000; the data may be greatly underestimated(1).
NIOSH (NOES Survey 1981-1983) has statistically estimated that 20,455 workers (6,018 of these were female) were potentially exposed to methyl acetate in the US(1). Occupational exposure to methyl acetate may occur through inhalation and dermal contact with this compound at workplaces where methyl acetate is produced or used. Monitoring data indicate that the general population may be exposed to methyl acetate via inhalation of ambient air, ingestion of food and dermal contact with this compound or other consumer products containing methyl acetate(SRC).
A survey was conducted in the second half of a work week on 39 male workers who were occupationally exposed to styrene in combination with methanol and methyl acetate during the production of plastic buttons. Time-weighted average exposure during an 8-h shift to styrene (Sty-A) and methyl acetate was monitored by carbon cloth-equipped personal samplers and to methanol by water-equipped ones. Urine samples were collected near the end of the shift and analyzed for mandelic (MA-U) and phenylglyoxylic acids (PhGA-U) by HPLC. Geometric mean styrene concentration was 12.4 ppm (micrograms/g) with the maximum of 46 ppm, whereas the values for methanol and methyl acetate in combination were 23.5 ppm and 229 ppm, respectively. The relationship of MA-U and PhGA-U with Sty-A was examined by linear regression analysis. The equations for the regression lines were compared with the results from a previous survey (Ikeda et al. 1983) in which workers were exposed only to styrene, and the methods employed were identical with that in the present study. The comparison showed no evidence to suggest that styrene metabolism is suppressed by coexposure to methanol and methyl acetate at low concentrations below the current occupational exposure limit of 200 ppm.
What is Methyl Acetate?
Methyl acetate (also known as methyl ethanoate, acetic acid methyl ester, MeOAc, Tereton, Devoton) is a carboxylate ester with a molecular formula of C3H6O2. It is a clear, colourless liquid that has a typical ester odour similar to glues and nail polish removers. It is very flammable with a flashpoint of -10° C and a flammability rating of 3. Methyl acetate is commonly used in low toxicity solvents such as glues, nail polish removers.
It is highly miscible with all common organic solvents (alcohols, ketones, glycols, esters) but has only slight miscibility in water, but becomes more soluble in water with elevated temperatures. It is commonly found in fruits such as apples, grapes and bananas.
Methyl acetate is a carboxylate ester as it contains a carbonyl group bonded to an OR group and is produced through the esterification of acetic acid with methanol.
How is methyl acetate produced?
There are various methods of producing methyl acetate. One that is used industrially is via carbonylation. These types of reactions bring together carbon monoxide substrates. To produce methyl acetate, methanol is heated alongside acetic acid in the presence of sulfuric acid. Another method of production is the esterification of methanol and acetic acid in the presence of a strong acid. Sulfuric acid is a common catalyst also used in this reaction.
Handling, Storage & Distribution
Hazards & Toxicity
Methly acetate has a NFPA health rating of 2 and can cause temporary incapacitation or residual injury. If inhaled or ingested, headaches, dizziness, drowsiness and fatigue can occur. Contact with the eyes can cause irritation. It has a flammability rating of 3 and can be ignited under most ambient temperature conditions residing from its low flash point of -10 °C. When ablaze, methyl acetate emits heavy, irritating, and toxic fumes that can travel considerable distances. These vapours are also explosive and risk bursting if able to return to the source of ignition.
Methyl acetate’s reactivity is aligned with other compounds of the ester group. In th
