Nitrobenzene toxicity, effect

Health and Safety Factors. The toxic effects of the mononitrotoluenes are similar to but less pronounced than those described for nitrobenzene. The maximum allowable concentration for the mononitrotoluenes is 2 ppm (11 mg/m ) (6). Mononitrotoluenes are low grade methemoglobin formers (4) and may be absorbed through the skin and respiratory tract. The toxicity of alkyl nitrobenzenes decreases with an increasing... 

Ingestion of alcohol aggravates the toxic effects of nitrobenzene. In general, higher ambient temperatures increase susceptibility to cyanosis from exposure to methemoglobin-forming agents." p-Nitrophenol and p-aminophenol are metabolites of nitrobenzene, and their presence in the urine is an indication of exposure."... 

Altenburger R, Schmitt H, Schuurmann G. 2005. Algal toxicity of nitrobenzenes combined effect analysis as a pharmacological probe for similar modes of interaction. Environ Toxicol Chem 24 324-333. 

No single or multigeneration reproduction studies in animals were found. However, an acute systemic study in rats indicated that the testes are sensitive to the toxic effects of nitrobenzene. Typical signs included testicular degeneration and transiently decreased sperm production following a single oral dose of 300 mg/kg (Levin et al. 1988). 

Cases of severe and nearly lethal toxic effects after dermal exposure to aniline-based dyes have been reported as early as 1886. These cases have involved mainly infants exposed to dye-stamped diapers and persons wearing freshly dyed shoes. The resulting condition was often termed "nitrobenzene poisoning", even though exposure to nitrobenzene did not necessarily occur. Several conclusions and generalizations about the dermal absorption and toxic effects of nitrobenzene, especially in infants, seem to have been based on these studies which should more appropriately be considered as part of the data base for aniline. 

Other toxic effects. Other solvents may affect other target organs (e.g. w-hexane causes peripheral neuropathy, nitrobenzene causes cyanosis, dichloromethane causes carboxyhaemoglobinaemia, methanol causes damage to the optic nerve) and it is important that the user establishes the likely hazards arising from the use of any specific solvent before such use commences. 

Nitromethane detonates on impact and under the effect of violent overpressure. Due to the lower toxicity of nitromethane it was often used instead of nitrobenzene, which is a solvent for the Friedel-Crafts reactions. Nitromethane boils at a lower temperature (101°C) than nitrobenzene (210°C), which forces the operation to proceed in an autoclave at the same temperature as with nitrobenzene (155°C) at a pressure of 10 bar. Under such conditions an exothermic reaction has caused nitromethane to detonate and the autoclave to be destroyed. 

The heat of decomposition (238.4 kJ/mol, 3.92 kJ/g) has been calculated to give an adiabatic product temperature of 2150°C accompanied by a 24-fold pressure increase in a closed vessel [9], Dining research into the Friedel-Crafts acylation reaction of aromatic compounds (components unspecified) in nitrobenzene as solvent, it was decided to use nitromethane in place of nitrobenzene because of the lower toxicity of the former. However, because of the lower boiling point of nitromethane (101°C, against 210°C for nitrobenzene), the reactions were run in an autoclave so that the same maximum reaction temperature of 155°C could be used, but at a maximum pressure of 10 bar. The reaction mixture was heated to 150°C and maintained there for 10 minutes, when a rapidly accelerating increase in temperature was noticed, and at 160°C the lid of the autoclave was blown off as decomposition accelerated to explosion [10], Impurities present in the commercial solvent are listed, and a recommended purification procedure is described [11]. The thermal decomposition of nitromethane under supercritical conditions has been studied [12], The effects of very high pressure and of temperature on the physical properties, chemical reactivity and thermal decomposition of nitromethane have been studied, and a mechanism for the bimolecular decomposition (to ammonium formate and water) identified [13], Solid nitromethane apparently has different susceptibility to detonation according to the orientation of the crystal, a theoretical model is advanced [14], Nitromethane actually finds employment as an explosive [15],... 

These studies indicate that intestinal microfloral metabolism and red blood cell toxicity of nitrobenzene is markedly different in animals fed cereal-based versus purified diets. Furthermore, since inclusion of pectin into the purified diet diminishes the magnitude of these effects, differences in dietary composition of fermentable carbohydrates in cereal-based and purified diets may mediate differences in metabolism and toxicity of nitrobenzene (27). 

ACGIH TLV TWA 2 mg(Al)/m3 DOT CLASSIFICATION 8 Label Corrosive SAFETY PROFILE Moderately toxic by ingestion. Experimental teratogenic and reproductive effects. Mutation data reported. The dust is an irritant by ingestion, inhalation, and skin contact. Highly exothermic polymerization reactions with alkenes. Incompatible with nitrobenzenes or nitrobenzene + phenol. Highly exothermic reaction with water or steam produces toxic ftimes of HCl. See also ALUMINUM COMPOUNDS, CHLORIDES, and HYDROCHLORIC ACID. 

Other experimental reproductive effects. Human systemic effects by inhalation pulmonary vascular resistance changes, cough, dyspnea, and other pulmonary changes. Mutation data reported. Violent reaction with cyclohexane, F2, formaldehyde, alcohols, nitrobenzene, petroleum, toluene. When heated to decomposition it emits toxic fumes of NOx. See also NITRIC OXIDE. 

Nitrobenzene is toxic by all routes including skin absorption. Systemic effects may be delayed a few hours. Poisoning closely resembles aniline. Initial care should include adequate gastrointestinal (gastric lavage as indicated and activated charcoal) and dermal decontamination. The patient should be given oxygen and monitored for cyanosis. Cardiac rhythm should be monitored in symptomatic patients. 

Differences in species and possibly strain susceptibility to the renal effects of nitrobenzene exposure may exist, but their relevance to the potential renal effects in humans is not clear. The occurrence of renal effects in male rats, but not female rats or mice of either sex, in response to exposure to chemical toxicants is not unique to nitrobenzene. These differences have also been found with exposure to 1,4-dichlorobenzene, isophorone, and unleaded gasoline (Charbonneau and Swenberg 1988) and have been attributed to the production of high concentrations of the protein alpha- 2 i -globulin in the kidneys of male rats, but not in female rats, mice, or humans. These observations suggest that the severe renal effects observed in male rats exposed to nitrobenzene will probably not occur in exposed humans. 

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