2-Methylimidazole

log Kow = 0.24

0.24

Other Solid; Dry Powder; Large Crystals; Liquid

Solid; [HSDB] Colorless solid; [NTP] Crystalline solid; [Alfa Aesar MSDS]

Danger

H360Df: May damage the unborn child; Suspected of damaging fertility [Danger Reproductive toxicity]

P203, P280, P318, P405, and P501 (click each P-code to see the statement)

This chemical does not meet GHS hazard criteria for 8.4% (64 of 758) of reports.

Danger

H302 (81.9%): Harmful if swallowed [Warning Acute toxicity, oral]

Chemical: 1H-Imidazole, 2-methyl-

Hazard Traits - Carcinogenicity; Reproductive Toxicity

1H-Imidazole, 2-methyl- is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of 1H-Imidazole, 2-methyl- are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

Status: Active Update: 31-05-2021 https://echa.europa.eu/registration-dossier/-/registered-dossier/5866

Substance: 2-methylimidazole

2-Methylimidazole: Does not have an individual approval but may be used under an appropriate group standard

Causes neurological effects including convulsions and tremors in livestock and experimental animals; Changes in thyroid hormone concentrations, anemia, and testicular degeneration observed in studies of rodents; [NTP] Causes burns; Inhalation may cause corrosive injuries to upper respiratory tract and lungs; Toxic by ingestion; [Alfa Aesar MSDS] See 4-Methylimidazole.

Department of Health & Human Services/National Institute of Environmental Health Sciences, National Toxicology Program; Toxicology and Carcinogenesis Studies of 2-Methylimidazole (CAS No. 693-98-1) in F344/N Rats and B6C3F1 Mice (Feed Studies), NTP TR 516 (December 2004).

Acute Tox. 4 (81.9%)

Acute toxicity (ingestion) - category 4

Acute toxicity (Oral) - Category 4

Reproductive toxicity - Category 1B

Repr. 1B

Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.

Special protective equipment for fire-fighters: Wear self contained breathing apparatus for fire fighting if necessary.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a POTW is acceptable only after review by the governing authority. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must meet Hazardous Material Criteria for disposal.

Personal precautions: Use personal protective equipment. Avoid dust formation. Avoid breathing dust. Ensure adequate ventilation. Evacuate personnel to safe areas.

Environmental precautions: Do not let product enter drains.

Methods for cleaning up: Pick up and arrange disposal without creating dust. Keep in suitable, closed containers for disposal.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. Observe all federal, state, and local environmental regulations. Contact a licensed professional waste disposal service to dispose of this material.

Handling: Avoid formation of dust and aerosols.

In case of skin contact: Take off contaminated clothing and shoes immediately. Wash off with soap and plenty of water. Consult a physician.

In case of eye contact: Continue rinsing eyes during transport to hospital. Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.

Hygiene measures: Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday.

Respiratory protection: Where risk assessment shows air-purifying respirators are appropriate use a full-face particle respirator type N100 (US) or type P3 (EN 143) respirator cartridges as a backup to engineering controls. If the respirator is the sole means of protection, use a full-face supplied air respirator. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).

Hand protection: Handle with gloves.

Eye protection: Safety glasses.

Skin and body protection: Choose body protection according to the amount and concentration of the dangerous substance at the work place.

Provide appropriate exhaust ventilation at places where dust is formed. Normal measures for preventive fire protection.

LC50; Species: Pimephales promelas (Fathead minnow, age 30 days, mean length 22.8 mm, mean weight 0.206 g); Conditions: flow through, 24.5 °C, pH 7.68, hardness 44.4 mg/L CaCO3, alkalinity 47.5 mg/L CaCO3, dissolved oxygen 6.0 mg/L; Concentration: 286 mg/L for 96 hr (95% confidence limit: 267-307 mg/L) /99% purity/

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 33(SRC), determined from a log Kow of 0.24(2) and a structure estimation method(3), indicates that 2-methylimidazole is expected to have very high mobility in soil(SRC). The pKa of 2-methylimidazole is 7.86(4), indicating that this compound will partially exist in cation form in the environment and cations generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(5). Volatilization of 2-methylimidazole from moist soil surfaces may be an important fate process(SRC) given an estimated Henry's Law constant of 4.1X10-6 atm-cu m/mole(SRC), using a fragment constant estimation method(6). However, volatilization from moist soil may be attenuated because the compound exists partially as a cation and cations do not volatilize. 2-Methylimidazole is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 6.9X10-4 mm Hg at 25 °C(SRC), determined from a fragment constant method(7). Utilizing the Japanese MITI test, 1% of the Theoretical BOD was reached in four weeks(8) indicating that biodegradation is not an important environmental fate process in soil(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 33(SRC), determined from a log Kow of 0.24(2) and a structure estimation method(3), indicates that 2-methylimidazole is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces may be expected(4) based upon an estimated Henry's Law constant of 4.1X10-6 atm-cu m/mole(SRC), developed using a fragment constant estimation method(5). Using this Henry's Law constant and an estimation method(4), volatilization half-lives for a model river and model lake are 190 hours and 62 days, respectively(SRC). According to a classification scheme(6), an estimated BCF of 3.2(SRC), from its log Kow(2) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Utilizing the Japanese MITI test, 1% of the Theoretical BOD was reached in four weeks(8) indicating that biodegradation is not 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), 2-methylimidazole, which has an estimated vapor pressure of 6.9X10-4 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 2-methylimidazole 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 4.1 hours(SRC), calculated from its rate constant of 9.4X10-11 cu cm/molecule-sec at 25 °C(3) that was derived using a structure estimation method(3). 2-Methylimidazole 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).

The Koc of 2-methylimidazole is estimated as 33(SRC), using a log Kow of 0.24(1) and a structure estimation method(2). According to a classification scheme(3), this estimated Koc value suggests that 2-methylimidazole is expected to have very high mobility in soil. The pKa of 2-methylimidazole is 7.86(4), indicating that this compound will partially exist in cation form in the environment and cations generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(5).

/SIGNS AND SYMPTOMS/ May be harmful if inhaled. Material is extremely destructive to the tissue of the mucous membranes and upper respiratory tract. May be harmful if absorbed through skin. Causes skin burns. Causes eye burns. May be harmful if swallowed. Causes burns.

2-Methylimidazole's production and use in the manufacture of pharmaceuticals, photographic and photothermographic chemicals, dyes, pigments, agricultural chemicals and rubber(1) may result in its release to the environment through various waste streams(SRC).

2-Methylimidazole

Group 2B: Possibly carcinogenic to humans

Volume 101: (2012) Some Chemicals Present in Industrial and Consumer Products, Food and Drinking-water

2013

2011

2-Methylimidazole

An estimated BCF of 3.2 was calculated in fish for 2-methylimidazole(SRC), using a log Kow of 0.24(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), provided the compound is not metabolized by the organism(SRC).

The Henry's Law constant for 2-methylimidazole is estimated as 4.4X10-6 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that 2-methylimidazole may be 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 190 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 62 days(SRC). 2-Methylimidazole's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). 2-Methylimidazole is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 6.9X10-4 mm Hg(SRC), determined from a fragment constant method(3).

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ ... Groups of five male and five female Fischer rats and B6C3F1 mice were administered 2-methylimidazole (2MI) by dosed feed at 0, 1,200, 3,300, or 10,000 ppm ... for 15 days, and groups of 10 male and 10 female Fischer rats and B6C3F1 mice were administered 2MI ... at 0, 625, 1,250, 2,500, 5,000 or 10,000 ppm for 14 weeks. In the 15-day studies, 2MI induced thyroid follicular-cell hyperplasia and pituitary pars-distalis hypertrophy in rats and thyroid follicular-cell hypertrophy and spleen hematopoietic-cell proliferation in mice ... In the 14-week studies, 2MI increased concentrations of thyroid-stimulating hormone (TSH) and decreased those of thyroxine (T(4)) and triiodothyroxine (T(3)) in male and female rats according to the dosage. Incidences of diffuse follicular-cell hyperplasia of the thyroid gland increased significantly in male rats exposed to 1,250 ppm or greater and female rats exposed to 2,500 ppm or greater. Thyroid follicular-cell adenoma was diagnosed in two males in the 10,000-ppm group. A dose-related anemia occurred in female rats. In mice, follicular-cell hypertrophy of the thyroid gland, anemia, splenic hematopoietic-cell proliferation, and hemosiderin in kidney tubules appeared ...

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ Groups of male and female Fischer 344/N rats were fed diets containing 0, 300, 1,000, or 3,000 ppm (males) or 0, 1,000, 2,500, or 5,000 ppm (females) 2-methylimidazole (2MI) for 106 weeks and groups of male and female B6C3F1 mice were fed 0, 625, 1,250, or 2,500 ppm 2MI for 105 weeks. Animals in each group were sacrificed at 8 days, 14 weeks, and 6 months for determinations of serum thyroid hormone and liver enzyme levels and histopathological examinations and at 2 years for evaluations of neoplastic lesions. In rats, 2MI administration reduced serum thyroxine and triiodothyronine and increased thyroid stimulating hormone levels. 2MI administration also increased total hepatic UDP-glucuronosyltransferase levels. At 2 years, the incidences of thyroid follicular cell hyperplasia, adenoma or carcinoma (combined), as well as follicular mineralization were increased. The incidences of hepatocellular adenoma or carcinoma (combined) in the two highest dose groups of males and females were also increased. The incidences of mixed cell focus in males and females were also significantly increased. In mice, the incidences of thyroid follicular cell hypertrophy and hyperplasia were significantly increased in the high dose males and females. The incidence of thyroid follicular cell adenoma in the 2,500 ppm males was significantly greater than that in the control group. The incidences of hepatocellular adenoma or carcinoma (combined) were significantly increased in all exposed groups of males and in the 2,500 ppm females. Significant increases in incidences were also observed in spleen hematopoietic cell proliferation in both sexes and bone marrow hyperplasia, chronic active inflammation of the epididymis, sperm granuloma, and germinal epithelial atrophy of the testis in males. Under these experimental conditions, carcinogenic activity of 2MI was demonstrated in male and female rats and mice.

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ Two-year mouse and rat bioassay studies of 2-methylimidazole (2-MI) conducted by the National Toxicology Program revealed that epididymal sperm granuloma(SG)s occurred only in male B6C3F1 mice in a dose-related manner. The present study characterized 2-MI-induced SGs in these epididymides. Groups of 50 male B6C3F1 mice were fed diets containing 0, 625, 1250, or 2500 ppm 2-MI for 105 weeks; the doses were equivalent to average daily doses of approximately 13, 40, or 130 mg/kg. Testes and epididymides were histopathologically reexamined. 2-Methylimidazole increased the incidence of epididymal SGs (0%, 0%, 6%, 12%, respectively). Histologically, most of the SGs exhibited rupture of epididymal ducts with focal aggregations of macrophages in interstitia. Lesions occurred in the proximal caput of the epididymis and/or efferent ducts, not in the corpus and cauda. In the testis, incidences of germinal epithelial atrophy (GEA) increased dose-relatedly (2%, 8%, 16%, 28%, respectively). All mice with epididymal SG developed testicular GEA. The grading scores of testicular GEA tended to be more severe in mice with SGs than those without. No epididymal SG or testicular GEA was observed in 6-month-interim-sacrificed mice. The results imply that 2-year treatment of B6C3F1 mice with 2-MI can induce epididymal SGs, primarily followed by more severe testicular GEA. The potential mechanism of SG induction by 2-MI is discussed.

The rate constant for the vapor-phase reaction of 2-methylimidazole with photochemically-produced hydroxyl radicals has been estimated as 9.4X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 4.1 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 2-Methylimidazole is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(2).

The toxicokinetics of 2-methylimidazole (2-MI) were studied in male and female Fischer 344 rats after a single iv dose of 10 mg/kg or gavage dose of 25, 50, or 100 mg/kg. The 2-MI was formulated in 0.05 M phosphate-buffered saline (pH 7.4) ... The estimated half-life value for 2-MI was about 1 hr for the iv group and the male 25-, 50-, or 100-mg/kg groups and female 25-mg/kg groups ...

... The disposition of [2-(14)C]-2-methylimidazole (2-MI) has been investigated following po administration of either 5, 50, or 150 mg/kg to male F344 rats. Excretion data indicated that absorption of 2-MI was both rapid and proportional to dose in the range studied. Approximately 90% of the total dose was eliminated in urine within 24 hr. Most of the remaining 14C was excreted in feces and as expired 14CO2. Excretion data were similar following iv administration of 5 mg/kg. Little or no enterohepatic circulation of compound occurred, since biliary excretion of 2-MI-derived 14C was negligible. Approximately 70% of the 14C excreted in urine, following all dosing, consisted of parent compound. High-performance liquid chromatography (HPLC) chromatograms for all treatment groups were similar, indicating that metabolism of 2-MI in rats was not affected by dose or route of administration.

The toxicokinetics of 2-methylimidazole (2-MI) were studied in male and female Fischer 344 rats after a single iv dose of 10 mg/kg or gavage dose of 25, 50, or 100 mg/kg. The 2-MI was formulated in 0.05 M phosphate-buffered saline (pH 7.4). The iv profiles could be best described by a two-compartment model with first-order elimination. The terminal elimination half-life, volume of distribution at steady state, and clearance values were 0.78 and 0.85/hr, 1.5 and 1.9 L, and 4.97 and 12.0 L/hr/kg for males and females, respectively. After a gavage dose, the plasma concentration time profiles could be best described by a one-compartment model, no lag phase, and first-order absorption and elimination. The peak 2-MI plasma concentrations increased proportionately with dose and were reached within 35 to 50 min (T(max)) for all groups. The estimated half-life value for 2-MI was about 1 hr for the iv group and the male 25-, 50-, or 100-mg/kg groups and female 25-mg/kg groups. Clearance increased for the male 100- and female 50- and 100- mg/kg groups. For a given dose group, clearance was also two to three times greater for female rats when compared to male rats. Absolute bioavailability for 2-MI was estimated to approach 97%. The results of this study indicated that 2-MI was (1) rapidly and completely absorbed, (2) quickly eliminated, (3) cleared differently for females than for males, (4) affected somewhat by dose for females, and (5) unlikely to undergo tissue accumulation following repeated exposure.

Used to make pharmaceuticals, photographic and photothermographic chemicals, dyes, pigments, agricultural chemicals, and rubber; Also used in epoxy resin systems for semiconductor potting compounds and soldering masks, as dyeing auxiliary for acrylic fibers and plastic foams, and in polymers such as epoxy resin pastes and acrylic rubber-fluororubber; [HSDB] Present in caramel coloring, tobacco smoke, wine, soy sauce, and other foods; Also formed when ammonia is added to livestock feed to increase nutritional value; Used in various polymers including acrylic rubber-fluororubber laminates, films, adhesives, textile finishes, and epoxy silane coatings; [NTP]

Semiconductor Manufacturing [Category: Industry]

Dyeing auxiliary for acrylic fibers, plastic foams

Used in the manufacture of pharmaceuticals, photographic and photothermographic chemicals, dyes, pigments, agricultural chemicals and rubber; Used in epoxy resin systems for semiconductor potting compounds and soldering masks; Component of polymers including epoxy resin pastes, acrylic rubber-fluororubber

2023: 50,000 - <75,000 lb

Production volumes for non-confidential chemicals reported under the Inventory Update Rule. [Table#7424]

In the generally applicable Radziszewski reaction, a 1,2-dicarbonyl compound is condensed with an aldehyde and ammonia (R1 = H) in a molar ratio of 1:1:2, respectively. Replacement of a molar equivalent of ammonia with a primary amine (R1 = alkyl or aryl) leads to the corresponding 1-substituted imidazoles. The reaction is usually carried out in water or a water-alcohol mixture at 50 - 100 °C. Work-up may involve the usual processes (e.g., distillation, extraction, and crystallization). Distillation leads to imidazole with a purity > 99%. The yield is generally 60 - 85 %. ... Compounds used to prepare simple imidazoles by the Radziszewski reaction: Imidazole: 2-methylimidazole; Dicarbonyl compound: glyoxal; Aldehyde: acetaldehyde; Amine: ammonia.

Paint and Coating Manufacturing

1H-Imidazole, 2-methyl-: ACTIVE