Benzimidazole

118.14

118.14

109682

200-081-4

E24GX49LD8

759

DTXSID8024573

RHOMBIC, BIPYRAMIDAL PLATES IN WATER|Tabular crystals|Othrorombic and monoclinic modifications

29339990

28.7

1.3

Beige to brown Crystalline Powder or Crystals

1.227 g/cm³

170.5 °C

>360 °C

360°C

1.697

H2O: sparingly soluble ;xylene: soluble 1g in 2g (boiling)(lit.)

Store below +30°C.

Oral-rat LD50: 500 mg/kg; Oral-Mouse LD50: 2910 mg/kg

Flammable; burning produces toxic nitrogen oxide fumes

Weak base

5.3(at 25 °C)

5.3 (at 25 °C)|pKa= 5.48 @ 25 °C|pKa= 5.3 @ 25 °C

Dipole moment: 3.93 (Dioxane)

Insoluble in water.

Amines, Phosphines, and Pyridines

An amine. Neutralizes acids to form salts plus water. These acid-base reactions are exothermic. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen is generated in combination with strong reducing agents, such as hydrides. May be shock sensitive.

3

36/37/38

37/39-26-24/25

DD5425000

Xi

Ventilated, low temperature and dry

Irritant

Stable. Combustible. Incompatible with strong oxidising agents.

P261, P264, P270, P271, P273, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501

H302

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

Flash point data for this chemical are not available. It is probably combustible. (NTP, 1992)

|Warning|H302 (95.88%): Harmful if swallowed [Warning Acute toxicity, oral]|P264, P270, P301+P312, P330, and P501|Aggregated GHS information provided by 103 companies from 5 notifications to the ECHA C&L Inventory.

Fires involving this material can be controlled with a dry chemical, carbon dioxide or Halon extinguisher. (NTP, 1992)

SMALL SPILLS AND LEAKAGE: Should a spill occur while you are handling this chemical, FIRST REMOVE ALL SOURCES OF IGNITION, then you should dampen the solid spill material with 60-70% ethanol and transfer the dampened material to a suitable container. Use absorbent paper dampened with 60-70% ethanol to pick up any remaining material. Seal the absorbent paper, and any of your clothes, which may be contaminated, in a vapor-tight plastic bag for eventual disposal. Solvent wash all contaminated surfaces with 60-70% ethanol followed by washing with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned. STORAGE PRECAUTIONS: You should store this material in a refrigerator. (NTP, 1992)

RECOMMENDED RESPIRATOR: Where the neat test chemical is weighed and diluted, wear a NIOSH-approved half face respirator equipped with an organic vapor/acid gas cartridge (specific for organic vapors, HCl, acid gas and SO2) with a dust/mist filter. (NTP, 1992)

moderately toxic

LD50 Rat ip 385 mg/kg|LD50 Mouse oral 2910 mg/kg|LD50 Mouse iv 280 mg/kg

Benzimidazole's production and use as an intermediate in the synthesis of fungal pesticides(1) may result in its release to the environment through various waste streams.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 108(SRC), determined from a structure estimation method(2), indicates that benzimidazole is expected to have high mobility in soil(SRC). Volatilization of benzimidazole from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 3.7X10-7 atm-cu m/mole, using a fragment constant estimation method(3). Benzimidazole is not expected to volatilize from dry soil surfaces, based upon an estimated vapor pressure of 7.6X10-5 mm Hg(SRC), determined from a fragment constant method(4). There is no information on benzimidazole migration in soil, but benzimidazole-based fungicides Benlate and thiabendazole TBZ did not migrate any appreciable distance in soils(5). These fungicides applied to soil surfaces at 100 ug/g did not move more than 25 mm into the soil(5). Benzimidazole was inhibitory to individual strains of soil bacteria that could degrade benzimidazole-based fungicides(6); furthermore, benzimidazole did not support the growth of mixed cultures of microbes that could grow on benzimidazole-based fungicides(7). In contrast, in soil, repeated applications of benzimidazole led to its enhanced degradation(8). These findings suggest that benzimidazole degradation in soils is cometabolic, and that isolation of the appropriate pure cultures that perform the cometabolism has not yet been achieved(SRC).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 110(SRC), determined from an estimation method(2), indicates that benzimidazole is not expected to adsorb to suspended solids and sediment in water(SRC). At low pHs, when benzimidazole (pKa = 5.3(8)) exists in a primarily protonated form, it is expected to adsorb to suspended solids and sediments. Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 3.7X10-7 atm-cu m/mole(4). According to a classification scheme(5), an estimated BCF of 2.1(SRC), from a log Kow of 1.32(6) suggests the potential for bioconcentration in aquatic organisms is low. Benzimidazole is degraded in soils(7), and therefore biodegradation in water may be an important fate process.|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), benzimidazole, which has an estimated vapor pressure of 7.6X10-5 mm Hg at 25 °C(2), is expected to exist in the both the vapor and particulate phases in the ambient atmosphere. Vapor-phase benzimidazole 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 3.6 hours(SRC), calculated from its rate constant of 3.6X10-11 cu cm/molecule-sec at 25 °C(3). Particulate-phase benzimidazole may be removed from the air by wet and dry deposition(SRC). Benzimidazole absorbs light at 245, 271 and 278 nm, and therefore, has little potential for direct photolysis at environmental wavelengths (>290 nm).

The rate constant for the vapor-phase reaction of benzimidazole with photochemically-produced hydroxyl radicals has been estimated as 3.6X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 3.6 hours(SRC) at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Benzimidazole is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(3).

An estimated BCF of 2.1 was calculated for benzimidazole(SRC), using a log Kow of 1.32(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.

The Koc of benzimidazole is estimated as 110(SRC), using a log Kow of 1.32(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that benzimidazole is expected to have high mobility in neutral and basic soils. Benzimidazole's pKa of 5.3(4) indicates that it will be in the protonated form in acidic environments, and will tend to adsorb to soil particles and clays.

The Henry's Law constant for benzimidazole is estimated as 3.7X10-7 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that benzimidazole is expected to be nonvolatile from water surfaces(2). This Henry's Law constant indicates that benzimidazole is essentially non-volatile(SRC) from moist soils. Benzimidazole is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 7.6X10-5 mm Hg at 25 °C(SRC), determined from a fragment constant method(3).

Occupational exposure to benzimidazole may occur through inhalation and dermal contact with this compound at workplaces where benzimidazole is produced or used. (SRC)

Agents that kill parasitic worms. They are used therapeutically in the treatment of HELMINTHIASIS in man and animal. (See all compounds classified as Anthelmintics.)

Benzimidazoles have only limited solubility in water; consequently, minor differences in solubility tend to have a major effect on absorption. Thiabenzole is rapidly absorbed after oral ingestion ... Most of the drug is excreted in the urine ... as 5-hydroxythiabendazole ... . In contrast tablet forms of mebendazole are poorly and erratically absorbed ... And is extensively metabolized. ... Like mebendazole, albendazole is variably and erratically absorbed after oral administration, although its absorbtion may be increased when it is given with a fatty meal.

5-HYDROXYBENZIMIDAZOLE IS A MAJOR URINARY METABOLITE OF BENZIMIDAZOLE IN RAT.|SIXTY DAYS AFTER TREATMENT WITH BENZIMIDAZOLE, MELON PLANTS CONTAINED METABOLITES 2-AMINOBENZONITRILE, O-PHENYLENEDIAMINE, ANILINE|Thiabendazole ... Is excreted in the urine as 5-hydroxythiabendazole, conjugated either as the glucuronide or as the sulfate. /Benzimidazoles/

Benzimidazole prevent tubulin polymerization or spindle movement and their administration can result in aneuploidy.

ACUTE/CHRONIC HAZARDS: When heated to decomposition this compound emits highly toxic fumes. (NTP, 1992)

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment. INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing. INGESTION: DO NOT INDUCE VOMITING. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. Be prepared to transport the victim to a hospital if advised by a physician. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. IMMEDIATELY transport the victim to a hospital. (NTP, 1992)

benzimidazole

1H-Benzimidazole: ACTIVE|EFFECTIVE AGENT TO PREVENT TOXIC EFFECT OF AIR POLLUTANTS, SUCH AS OXIDANTS, ON PLANTS.|Not currently registered

GAS CHROMATOGRAPHIC-MASS SPECTROMETRIC ANALYSIS OF BENZIMIDAZOLE NUCLEOSIDE IN ESCHERICHIA COLI RIBONUCLEIC ACID.

Environmental transformation -> Pesticide transformation products (metabolite, successor)

Benzimidazole is a known environmental transformation product of Thiabendazole.