Nitrobenzene toxicity

Beauchamp RO Jr, Irons RD, Rickert DE, et al A critical review of the literature on nitrobenzene toxicity. CRC Crit Rev Toxicol 11 33-84, 1982... 

The reduction of nitro groups may also be catalyzed by microsomal reductases and gut bacterial enzymes. The reduction passes through several stages to yield the fully reduced primary amine, as illustrated for nitrobenzene (Fig. 4.39). The intermediates are nitrosobenzene and phenylhydroxylamine, which are also reduced in the microsomal system. These intermediates, which may also be produced by the oxidation of aromatic amines (Fig. 4.21), are involved in the toxicity of nitrobenzene to red blood cells after oral administration to rats. The importance of the gut bacterial reductases in this process is illustrated by the drastic reduction in nitrobenzene toxicity in animals devoid of gut bacteria, or when nitrobenzene is given by the intraperitoneal route. 

Cronin, M.T.D., Gregory, B.W., and Schultz, T.W., Quantitative structure-activity analyses of nitrobenzene toxicity to Tetrahymena pyriformis, Chem. Res. Toxicol., 11, 902-908, 1998. 

Measure nitrobenzene (toxic) in the hood. Do not breathe the vapors. 

Estrada, E. and Uriarte, E. (2001a) Quantitative structure-toxicity relationships using TOPS-MODE. 1. Nitrobenzene toxicity to Tetrahymena pyriformis. SAR SI QSAR Environ, Res., 12, 309-324. 

Populations that are considered unusually susceptible to nitrobenzene toxicity are those groups that are susceptible to methemoglobinemia. The newborn infant is especially vulnerable to methemoglobinemia due to the following factors (Goldstein et al. 1969 Von Oettingen 1941) ... 

Nitrobenzene (and many other liquid organic compoimds containing nitrogen) is appreciably toxic and its vapour should not be allowed to escape into the atmosphere of the laboratory the delivery tube of the condenser should pass well into the mouth of the receiver flask. The liquid is also a skin poison if it Is accidentally spilled on the skin, it should be removed by washing with a litt e methylated spirit, followed by soap and warm water. 

Health nd Safety Factors. The mononitrochlorobenzenes are toxic substances which may be absorbed through the skin and lungs giving rise to methemoglobin. Their toxicity is about the same as or greater than that of nitrobenzene. The para isomer is less toxic than the ortho isomer, and the maximum allowable concentration that has been adopted for -nitrochlorobenzene is 1 mg/m (0.1 ppm) (6). The mononitrochlorobenzenes are moderate fire hazards when exposed to heat or flame. They ate classified by the ICC as Class-B poisons. The same handling precautions should be used for these compounds as are used for nitrobenzene. 

Dinitrochlorobenzene is used primarily in the manufacture of azo dyes other areas include the manufacture of fungicides, mbber chemicals, and explosives. It is produced by Eastman Kodak Company and Sandoz Chemical Corporation and its bulk fob price is 2.73/kg. 2,4-Dinitrochlorobenzene is more toxic than nitrobenzene. It is an extremely powerful skin irritant and must be handled with great cate. 

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... 

NOTE - Petrochemical plants also generate significant amounts of solid wastes and sludges, some of which may be considered hazardous because of the presence of toxic organics and heavy metals. Spent caustic and other hazardous wastes may be generated in significant quantities examples are distillation residues associated with units handling acetaldehyde, acetonitrile, benzyl chloride, carbon tetrachloride, cumene, phthallic anhydride, nitrobenzene, methyl ethyl pyridine, toluene diisocyanate, trichloroethane, trichloroethylene, perchloro-ethylene, aniline, chlorobenzenes, dimethyl hydrazine, ethylene dibromide, toluenediamine, epichlorohydrin, ethyl chloride, ethylene dichloride, and vinyl chloride. 

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],... 

Goswami and Sarkar3 claimed to have prepared methyl and ethyl fluoroformates by the action of thallium fluoride on the corresponding chloroformates. These fluoroformates were described as powerful lacrimators. We found that no appreciable reaction took place between potassium fluoride and ethyl chloroformate in boiling carbon tetrachloride or nitrobenzene. Ethyl fluoroformate could, however, be readily produced by the action of potassium fluoride on ethyl chloroformate by using the autoclave technique. It was found not to have the lacrimatory properties claimed for it, and was non-toxic in comparison with M.F.A. This non-toxicity was to be expected, as the fluoroformate contains the COF and not the CH2F- group. 

Yuan, X. and Lang, P. QSAR study of the toxicity of nitrobenzenes to river bacteria and Photobacteriumphosphoreum. Bull... 

Deneer JW, Sinnige TL, Seinen W. 1987. Quantitative structure-activity relationships for the toxicity and bioconcentration factor of nitrobenzene derivatives towards the guppy (Poecilia reticulata). Aquat Toxicol 10 115-129. 

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."... 

Hamm TE Jr Ninety-Day Inhalation Toxicity Study of Nitrobenzene in F344 Rats, CD Rats, and B6C3F1 Mice Final Study Report. Research Triangle Park, NC, CRT, 1984... 

Medinsky MA, Irons RD Sex, strain and species differences in the response of rodents to nitrobenzene vapors. In Rickert DE (ed) The Toxicity of Nitroaromatic Compounds, pp 35-51. New York, Hemisphere Publishing, 1985... 

Catdey RC, Everitt JI, Gross EA et al Carcinogenicity and toxicity of inhaled nitrobenzene in B6C3F1 mice and F344 and CD rats. Fundam Appl Toxicol 22 328-340, 1994... 

Mitsumori K, Kodama Y, Uchida O, et al Confirmation study, using nitrobenzene, of the combined repeat dose and reproductive/ developmental toxicity test protocol pro-... 

N 5.83% mp 83°, is not listed as an explosive, but its anhydrous Potassium salt explodes with violence at 160-165° and the Sodium salt (also called Chloramine T) at 175-180°.. Large quan tities of the Na salt are toxic (Refs 3 12) Nitrobenzene-m-sulfonchloramide, Potassium and Sodium Salts. 02NC6H4S02K NC1 mw 274.72, N 10.20% and 02NC6H4S02Na NCl mw 258.61, N 10.83%. Both anhydrous salts are explosive. The first explodes at 155° the second at 175° (Ref 12)... 

Phosphorus pentabromide [7789-69-7] M 430.6, m <100°, b 106°(dec). Dissolved in pure nitrobenzene at 60°, filtering off any insoluble residue on to sintered glass, then crystallised by cooling. Washed with dry Et2O and removed the ether in a current of dry N2. (All manipulations should be performed in a dry-box.) [Harris and Payne JCS 3732 1958], Fumes in moist air because of hydrolysis. TOXIC. 

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