Methyl-4-nitrophenol

See entry alkyl nitrates See other BENZYL compounds 2766. 3-Methyl-4-nitrophenol... 

Dartnell, R. C. et al., Loss Prev., 1971, 5, 53-56 MCA Case History No. 1649 A batch of 8 t of material accumulated in storage at 154°C during 72 h decomposed explosively. Stability tests showed that thermal instability developed when 3-methyl-4-nitrophenol is stored molten at temperatures above 140°C. Decomposition set in after 14 h at 185° or 45 h at 165°, with peak temperatures of 593 and 521°C, respectively. In a closed vessel, a peak pressure of 750 bar was attained, with a maximum rate of increase of 40 kbar/s. Thermal degradation involves an initially slow exothermic free radical polymerisation process, followed by a rapid and violently exothermic decomposition at take-off. 

Whereas in acetonitrile the rate limiting step is an opening of the solvent shell of a reactant, in benzonitrile the back reaction of (5) between the protonated acridine orange cation (BH ) and the 3-methyl-4-nitrophenolate ion (A ) to form the ion pair is diffusion controlled (although the overall reaction to the neutral molecules is an endothermic process). Because of its lower dielectric constant than acetonitrile, the electrostatic interactions between reactants in benzonitrile outweigh specific solvent effects. In other words, in benzonitrile a rate limiting coupling of proton transfer to the reorientation of solvent dipoles does not occur and the measured rates are very fast. The ion recombination (I) + (II) in benzonitrile has a diffusion controlled specific rate (theoretical) k = 9 -1 -1... 

In water, the percentage of these degradation products increased with time and amounted to one quarter of the remaining radiocarbon at 24 hr the quantity of 3-methyl-4-nitrophenol and both demethylated products is ca. 7% and 5.5%, respectively. Fenitrooxon was also detected. Because fenitrothion was stable in water under the present experimental conditions, these degradation products are presumably produced by fish metabolism. 

Baarschers, W.H., Elvish, J., and Ryan, S.P. Adsorption of fenitrothion and 3-methyl-4-nitrophenol on soils and sediment, Bull. Environ. Contam. Toxicol, 30(5) 621-627, 1983. 

Methyl-4-nitrophenol, 2762 2-Methyl-5-nitroaniline, 2797 2-Methyl-5-nitrobenzenesulfonic acid, 2768 2-Methyl-5-nitrobenzimidazole, 2935... 

Analytical standards. Fenitrothion (1 C-ring-labelied, sp. act. 73.7 pCi/mg) was provided by Sumitomo Chemical Co. Ltd.. Fenitrothion, fenitrooxon (FO), S-methyl fenitrothion (SMF), and amino-fenitrothion (AF) were obtained from R. Greenhalgh (Agriculture Canada, Ottawa). The hydrolysis product 3-methyl-4-nitrophenol (MNP) was obtained from Aldrich Chemicals, St. Louis. Standards were prepared in ethyl acetate or methanol. 

Animals. Rapidly excreted in the urine and feces. After 3 days c. 90% has been excreted by rats, mice and rabbits. The most important metabolites are dimethylfenitrooxon and 3-methyl-4-nitrophenol... 

C7H7N03 3-methyl-4-nitrophenol 2581-34-2 28.40 1.2744 2 10820 C7H8N202 4-hydroxybenzoic acid hydrazide 5351-23-5 92.67 1.2333 2... 

Determination of 4-nitrophenol and 3-methyl-4-nitrophenol, urine exposure markers of OPP like parathion, parathion methyl, and fenitrothion, using coupled-colunm LC-LC-MS-MS. A second method was developed for the determination of other parathion and parathion methyl metabohtes, such as dimethyl thiophosphate, dimethyl phosphate, 4-nitrophenyl sulfate, and 4-nitrophenol glucmonide [145]. 

Fenitrothion, an organophosphate/contact insecticide, is chemically known as 0,0-dimethyl 0-(4-nitro-m-tolyl) phosphorothio-ate, or 0-0-dimethyl-0-3-methyl-4-nitrophenol phospherothioate. 

Urine samples were analyzed with the same procedure for determination of 3-methyl-4-nitrophenol, acetylaminofenitroxon and 5-methylfenitrothion. 

The ester cleavage of fenitrothion leads to the formation of the metabolite 3-methyl-4-nitrophenol (MNP). Shafik et al. used GC-ECD for the detection of MNP in occupationally exposed subjects. Sample preparation involved extraction with diethyl ether, derivatization with diazoethane and purification on silica gel columns. The LOD was determined as 50 pgL with a recovery of 88-98%. 

Other Decapod Crustacea. The fate of the pesticide fenitrothion has been studied in blue crabs, Callinectes sapidus, after water-borne exposure to 5.2 ppb for 48 hours (86). The hepatopancreas was the major organ of uptake (0.3 ig fenitrothion equivalents/g after 48 hours), and concentrations in muscle were very low (0.026 ig/g), although muscle concentrations were almost 4 times higher than hemolymph concentrations (86). The major metabolites of fenitrothion found in hepatopancreas were fenitrooxon, desmethylfenitrooxon and 3-methyl-4-nitrophenol, and these metabolites were also recovered from the tank water (86). 

---