5-Nitrobenzimidazole

163.136

163.13

202-341-2

A7V95AYT2T

58858|3068

2811

DTXSID8020965

Solid|NEEDLES FROM WATER

2933990090

74.5

1.64

6-nitrobenzimidazole is an off-white to pale yellow fluffy powder. (NTP, 1992)

1.5±0.1 g/cm3

203 °C

475.7±18.0 °C at 760 mmHg

241.5±21.2 °C

1.741

H2O: <0.01 g/100 mL at 16.5 ºC

Store in a cool, dry place. Store in a tightly closed container.

Insoluble in water.

Amines, Phosphines, and Pyridines

6-NITROBENZIMIDAZOLE is incompatible with strong oxidizing agents and strong bases. (NTP, 1992)

2811

3

R22;R40

S26-S45-S36/37

DD9800000

Xn:Harmful;

Stable. Combustible. Incompatible with strong oxidizing agents, strong bases.

P201, P202, P261, P264, P271, P273, P280, P281, P302+P352, P304+P340, P305+P351+P338, P308+P313, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501

H315

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.

Bioassay of 6-Nitrobenzimidazole for Carcinogenicity (1979) Technical Rpt Series No. 117 DHEW Pub No. (NIH) 79-1372, U.S. Department of Health Education and Welfare, National Cancer Institute, Bethesda, MD 20014

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

|Warning|H315 (83.33%): Causes skin irritation [Warning Skin corrosion/irritation]|P201, P202, P261, P264, P271, P273, P280, P281, P302+P352, P304+P340, P305+P351+P338, P308+P313, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, and P501|Aggregated GHS information provided by 48 companies from 6 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

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

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]: As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. SPILL: Increase, in the downwind direction, as necessary, the isolation distance shown above. FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2016)

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 at ambient temperatures away from all oxidizing materials. (NTP, 1992)

MINIMUM PROTECTIVE CLOTHING: If Tyvek-type disposable protective clothing is not worn during handling of this chemical, wear disposable Tyvek-type sleeves taped to your gloves. RECOMMENDED RESPIRATOR: Where the neat test chemical is weighed and diluted, wear a NIOSH-approved half face respirator equipped with a combination filter cartridge, i.e. organic vapor/acid gas/HEPA (specific for organic vapors, HCl, acid gas, SO2 and a high efficiency particulate filter). (NTP, 1992)

LD50 MOUSE WAS ESTIMATED TO BE 125-150 MG/KG.

A bioassay for possible carcinogenicity of 6-nitrobenzimidazole was conducted using Fischer 344 rats and B6C3F1 mice. /The cmpd/ was administered in the feed, at either two concentrations, to groups of 50 male and 50 female animals of each species. The dietary concentrations ... were 0.5 and 0.12% for high and low dose rats, respectively, and 0.24 and 0.12% for the high and low dose mice, respectively. After a 78 wk period of cmpd administration, observation of the rats continued for up to an additional 29 wk and observation of the mice continued for up to an additional 18 wk. For each species and each dosed group, 49 or 50 animals of each sex were placed on test as controls. ... Under the conditions of this bioassay, dietary administration of 6-nitrobenzimidazole was not carcinogenic to Fischer 344 rats; ... the cmpd was carcinogenic to B6C3F1 mice, causing hepatocellular carcinomas in both sexes. Levels of Evidence of Carcinogenicity: Male Rats; Female Rats: Negative; Male Mice: Positive; Female Mice: Positive.

5-Nitrobenzimidazole's production and use as an antifogging agent in photographic developers(1) 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 120(SRC), determined from a structure estimation method(2), indicates that 5-nitrobenzimidazole is expected to have high mobility in soil(SRC). Estimated pKa's(3) predicted for 5-nitrobenzimidazole are 3.7(SRC) (protonation of one of the nitrogens in the imidazole ring) and 10.6(SRC) (deprotonation of one of the nitrogens in the imidazole ring) using an estimation method from structure(3). Therefore, in neutral soils, 5-nitrobenzimidazole will exist in the uncharged form. In acidic soils, some will be protonated, and since protonated forms are more likely to bind to negatively charged soil particle surfaces, it will be less mobile. Volatilization of 5-nitrobenzimidazole from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 3.7X10-10 atm-cu m/mole(SRC), using a fragment constant estimation method(4). 5-Nitrobenzimidazole is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.7X10-7 mm Hg(SRC), determined from a fragment constant method(5). Biodegradation in soil is not expected to be an important environmental fate process(6). The nitro moeity may be enzymatically reduced by the "classic" nitroreductases, such as those found in Salmonella typhimurium(7). However, the resulting aminobenzimidazole is not biodegraded and is inhibitory to many microbes(8).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 120(SRC), determined from an estimation method(2), indicates that 5-nitrobenzimidazole is not expected to adsorb to suspended solids and sediment in water(SRC). Estimated pKa's(3) predicted for 5-nitrobenzimidazole are 3.7(SRC) (protonation of one of the nitrogens in the imidazole ring) and 10.6(SRC) (deprotonation of one of the nitrogens in the imidazole ring) using an estimation method from structure(3). Therefore, in neutral aquatic environments, 5-nitrobenzimidazole will exist in the uncharged form. In acidic waters, a portion of the 5-nitrobenzimidazole will be protonated. This protonated form will be more likely to bind to negatively charged sediments and suspended. Volatilization from water surfaces is not expected(4) based upon an estimated Henry's Law constant of 3.7X10-10 atm-cu m/mole(SRC), using a fragment constant estimation method(5). According to a classification scheme(6), BCFs of 0.7-1.8(7) suggests the potential for bioconcentration in aquatic organisms is low. Biodegradation in water is not expected to be an important environmental fate process(7).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 5-nitrobenzimidazole, which has an estimated vapor pressure of 1.7X10-7 mm Hg at 25 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 5-nitrobenzimidazole 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 days(SRC), calculated from its rate constant of 4.5X10-12 cu cm/molecule-sec at 25 °C, determined using a structure estimation method(3). Particulate-phase 5-nitrobenzimidazole may be removed from the air by wet and dry deposition(SRC). 5-Nitrobenzimidazole may also be degraded by direct photolysis, as it absorbs light in the environmental UV range (>290 nm); 5-nitrobenzimidazole absorbs UV at 302 nm(4).

The rate constant for the vapor-phase reaction of 5-nitrobenzimidazole with photochemically-produced hydroxyl radicals has been estimated as 4.5X10-12 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 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 5-Nitrobenzimidazole is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(3) nor to directly photolyze due to the lack of absorption in the environmental UV spectrum (>290 nm); 5-nitrobenzimidazole absorbs UV at 302 nm(4).

2.51|BCFs of 0.7-1.8 were measured for 5-nitrobenzimidazole(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low.

Using a structure estimation method based on molecular connectivity indices(1), the Koc for 5-nitrobenzimidazole can be estimated to be 120(SRC). According to a classification scheme(2), this estimated Koc value suggests that 5-nitrobenzimidazole is expected to have high mobility in soil. 5-Nitrobenzimidazole is predicted(3) to have two environmentally relevant pKa's, one at 3.7 and the other at 10.7, corresponding to the protonation and deprotonation of one of the nitrogens in the imidazole structure, respectively. Therefore, under neutral environmental conditions, 5-nitrobenzimidazole will exist in the uncharged form. At low pH, some 5-nitrobenzimidazole will be cationic, and in this form will be more likely to sorptive to soil particles.

The Henry's Law constant for 5-nitrobenzimidazole 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 5-nitrobenzimidazole is expected to be essentially nonvolatile from water surfaces(2). 5-Nitrobenzimidazole's Henry's Law constant(1) indicates that volatilization from moist soil surfaces may not occur(SRC). 5-Nitrobenzimidazole is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.7X10-7 mm Hg(SRC), determined from a fragment constant method(3).

NIOSH has statistically estimated that 4,200 workers (2,000 of these are female) are potentially exposed to 5-nitrobenzimidazole in the US(1).

EXPTL USE: RADIOBIOLOGICAL AND PHARMACOKINETIC ASSAYS WERE PERFORMED TO DETERMINE THE POTENTIAL OF 2-NITROBENZIMIDAZOLE (NBI) AS HYPOXIC CELL RADIOSENSITIZING AGENT. ACUTE TOXIC SIGNS APPEARED IN C3H/HEJ MICE FOLLOWING IP INJECTION OF NBI @ 100 MG/KG. THESE WOULD BE PARTLY ATTRIBUTABLE TO THE STRESS CAUSED BY THE HIGH PH OF THE INJECTION VEHICLE. ... MAMMARY ADENOCARCINOMA TUMORS GROWN IN THE FLANKS OF THESE MICE EXHIBITED MAXIMUM NBI LEVELS @ 5 MIN POSTINJECTION. PEAK TUMOR RADIOSENSITIZATION OCCURRED IN THE INTERVAL BETWEEN 5 AND 10 MIN POSTINJECTION. THE ENHANCEMENT RATIO FOR TUMOR REGROWTH DELAY WAS 2.1 +/- 0.3 FOLLOWING 50 MG/KG INJECTED INTO MICE 5 MIN BEFORE IRRADIATION. FUNCTIONAL EVALUATION UP TO 40 DAYS AFTER TREATMENT REVEALED NO EVIDENCE OF NEUROLOGICAL DEFICIT.

0.07 Days

SYMPTOMS: Exposure to this chemical can cause irritation. ACUTE/CHRONIC HAZARDS: When heated to decomposition this compound emits toxic fumes of carbon monoxide, carbon dioxide and NOx. This chemical is harmful by inhalation, ingestion, or skin absorption. (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. IMMEDIATELY call a hospital or poison control center even if no symptoms (such as redness or irritation) develop. IMMEDIATELY transport the victim to a hospital for treatment after washing the affected areas. INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. IMMEDIATELY call a physician and be prepared to transport the victim to a hospital even if no symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop. 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. OTHER: Since this chemical is a known or suspected carcinogen you should contact a physician for advice regarding the possible long term health effects and potential recommendation for medical monitoring. Recommendations from the physician will depend upon the specific compound, its chemical, physical and toxicity properties, the exposure level, length of exposure, and the route of exposure. (NTP, 1992)

ESSENTIALLY 100% AS PHOTOGRAPHIC CHEMICAL

1H-Benzimidazole, 6-nitro-: ACTIVE

GAS CHROMATOGRAPHY AND MASS SPECTROMETRY WERE USED TO ANALYZE BENZIMIDAZOLE IN E COLI RIBONUCLEIC ACID.