Substituted nitrophenol pesticides

SUBSTITUTED NITROPHENOL PESTICIDES, LIQUID, FLAMMABLE, TOXIC, 3013 ... 

Substituted nitrophenol pesticides, liquid, flammable, toxic, n.o.s., flash point less than 23 degrees C 2780... 

Substituted nitrophenol pesticides, those based on nitrophenol (25154-55-6), a fungicide, including the acaricide parathion. 

Solids Conlaining Poisonous Liquid, 3243 55 Substituted Nitrophenol Pesticides. 2780 28... 

Stannic Chloride, anhydrous Stannic Chloride, hydrated Stannic Phosphide 1827 2440 1433 39 60 41 liquid, toxic, n.o.s. Substituted Nitrophenol Pesticides, solid, toxic, n.o.s. 2779 53... 

SUBSTITUTED NITROPHENOL PESTICIDES. liquid, flammable, toxic, n.o.s. 

This family of organonitrogen pesticides includes the nitrophenols and their salts, for example, Dinoseb and the substituted dinitroanilines, trifluralin, and nitralin. Figure 3 shows a typical commercial process for the production of a dinitroaniline herbicide [8]. In this example, a chloroaromatic is charged to a nitrator with cyclic acid and fuming nitric acid. The crude product is then cooled to settle out spent acid, which can be recovered and recycled. Oxides of nitrogen... 

Another method is extraction with methylene chloride followed by derivatization with pentafluorobenzyl bromide or diazomethane and snbseqnent GC/ECD or GC/FID analysis . The extraction solvent has to be changed before analysis. More than 50 substituted phenols have been derivatized successfully with Af-(f-butyldimethylsilyl)-Af-methyltrifluoroacetamide by forming the corresponding f-bntyldimethylsilyl derivatives. This study includes 21 chlorinated phenols, 13 nitrophenols, 3 aminophenols, 4 alkylphenols, o-phenylphenol, some other substitnted phenols inclnding 6 phenolic pesticides and the nonsnbstitnted phenol. Using SPE with polymeric adsorbents and GC/MS, phenols with very different substituents can be detected in environmental samples with high matrix content at the ppt level . 

Hammett (and related sigma) relationships have been applied to aquatic reactions of several classes of aromatic contaminants. For example, alkaline hydrolysis of triaryl phosphate esters fits a Hammett relationship (Table 3) is t he sum of the substituent constants for the aromatic groups and k0 is the hydrolysis rate constant for triphenyl phosphate (0.27 M 1 s-1 t1/2 = 30 days at pH 8). Triaryl esters thus hydrolyze much more rapidly than trialkyl or dialkyl-monoaryl esters under alkaline conditions. Rates of photooxidation of deprotonated substituted phenols by singlet oxygen have been found to be correlated with Hammett a constants (Scully and Hoigne, 1987). The electronic cllects of substituents on pKa values of substituted 2-nitrophenols also fit a I lammett relationship this, of course, is not a kinetic LFER. Two compounds (4-phenyl-2-NP and 3-methyl-2-NP) did not fit the relationship and were not included in the regression. Steric effects may account for the discrepancy for the latter compound. Nitrophenols are used as intermediates in synthesis of dyes and pesticides and also used directly as herbicides and insecticides. 

Pedrosa VA, Codognoto L, Machado SAS et al (2004) Is the boron-doped diamond electrode a suitable substitute for mercury in pesticide analyses A comparative study of 4-nitrophenol quantification in pure and natural waters. J Electroanal Chcan 573 11-18... 

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