Pesticide aromatic

Alkyl-Hyd.roxyla.tion. This is commonly observed as the initial transformation of alkyl-substituted aromatic pesticides such as alachlor [15972-60-8] and metolachlor [51218-45-2] (eq. 2) (2) (16). These reactions are typically catalyzed by relatively nonspecific oxidases found in fungi and actinomycetes. 

Reductive DechIorina.tion. Such reduction of chlorinated aUphatic hydrocarbons, eg, lindane, has been known since the 1960s. More recentiy, the dechlorination of aromatic pesticides, eg, 2,4,5-T, or pesticide products, eg, chlorophenols, has also been documented (eq. 10) (20). These reactions are of particular interest because chlorinated compounds are generally persistent under aerobic conditions. 

Twenty-five acidic pesticides, most of which resulted from the rapid hydrolysis of the ester formulations, were isolated from the two pits. Thirty-nine substituted aromatic acids and phenols were also isolated from the pits. The source of these components was most likely the degradation of aromatic pesticides and the... 

Kiso Y., Y. Sigiura, T. Kitao, and K. Nishimura (2001). Effects of hydrophobicity and molecular size on rejection of aromatic pesticides with nanofiltration membranes. Journal of Membrane Science 192 1-10. 

Tratnyek, P. G. Macalady, D. L. (1989). Abiotic reduction of nitro aromatic pesticides in anaerobic laboratory system s. Journal of Agricultural and Food Chemistry, 37, 248-54. 

Haggblom, M. M. (1992). Microbial breakdown of halogenated aromatic pesticides and related compounds. FEMS Microbiology Reviews, 103, 29-72. 

Either photocatalysis or ozonation alone achieved rapid disappearance of aromatic pesticide. In contrast, mineralization (TOC removal) was slow for both. However, photocatalytic mineralization was enhanced considerably by ozone pretreatment (Fig. 9.16).31) This effect may be explained by ozonolytic cleavage of the aromatic ring and subsequent formation of aliphatic compounds which are more degradable by photocatalysis. Simultaneous use of photocatalyst and ozonation (illuminated by 254 nm light) showed synergetic effect on TOC removal (Fig. 9.17).32) In this process scavenging of electrons by ozone is considered to play the most important role. 

The rims of the CD are often derivatized to improve sensitivity by enhancing analyte association. Hydroxypropyl modification in general has proven useful for the detection of analytes by direct fluorescence and some assays have been successfully developed [250,251], For instance, Aaron and Coly have used both native and hydroxypropyl 3-CD to detect aromatic pesticides [252], Likewise, Zhang and Gong [253] have detected the biologically relevant substance, tryptamine, by monitoring its fluorescence within hydroxypropyl 3-CD. Ethyl modification of the bucket rim was sufficient to allow de Rossi et al. [254] to detect tetracycline by direct fluorescence. 

The degradation of aromatics, pesticides, herbicides, and other bio-recalcitrant compounds in industrial wastewaters can be efficiently achieved by means of the oxidative radicals generated in the Fenton and photo-assisted Fenton reaction [11], Among others, the photo-Fenton method has proved to be effective in the degradation of phenol and its halogenated derivatives [12-14], dioxins [15], nitroaniline [16],... 

Aryl-Hydroxylation, This is occasionally observed as the initial transformation of aromatic pesticides. The vast majority of aromatic pesticide degradation products are susceptible to aryl-hydroxylation, representing either cometaboHsm or the initial step in mineralization (17). Numerous genera of bacteria and fungi possess the monooxygenases and dioxygenases responsible for hydroxylation of aromatic products. Examples of aromatic products susceptible to aryl-hydroxylation include 2,4-dichlorophenol [120-83-2] (from 2,4-D) (eq. 3), 4-nitrophenol (from parathion) (eq. 4), 3,4-dichloroaniHne [95-76-1] (from propanil), and 3,6-dichlorosaHcyHc acid [3401-80-7] (from dicamba). 

Aromatic Pesticidal Compounds, Org. Mass Spectr. (1970) 3, 51-62 and references cited therein. 

Tratnyek, P. G., and D. L. Macalady (1989), Abiotic Reduction of Nitro Aromatic Pesticides in Anaerobic Laboratory Systems, J. Agric. Food Chem. 37, 248-254. 

PAHs can be eluted as a separate band although they may still coelute with chlorinated aromatics, pesticides, and nitroaromatics, thus necessitating another cleanup step prior to analysis. Another strategy is to separate the organic acids and phenols from soil/sediment extracts by performing a liquid-liquid extraction with 10 N NaOH. ° The solvent extract is shaken in a separatory funnel with three aliquots of concentrated NaOH. The combined extracts containing the acids and phenols is discarded while the extract, in DCM, is dried and concentrated for GC analysis or solvent exchanged for another analysis method. 

Hydroxide Ions. The photolysis of propanil, 4-CPA, and other chlorinated aromatic pesticides in water also can generate phenols through the replacement of halogen by hydroxyl groups (39, 41). Oxygen does not seem to have an important part in this reaction, if it is involved at all, and observation that the replacement proceeds upon irradiation... 

CDTM 6-TBDMS-2,3-Methyl-beta-CD PCB, polycycUc or chlorinated aromatics, pesticides... 

Jung, Y.J., Kiso, Y, Adawih binti Othman, R.A., Ikeda, A., Nishimura, K., Min, K.S., Kmnano, A. andAriji, A. 2005. Rejection properties of aromatic pesticides with a hoUow-fiberNF... 

Water purification treatment is currently a very hot subject within scientific research, and several books and reviews have been devoted to this problem [2, 3, 11, 36, 50-56]. One of the challenges facing water purification treatment is the elimination of low concentrations of toxic biorecalcitrants, particularly when present as components of complex mixtures, including chlorinated aromatics, pesticides, pharmaceuticals, hormones, surfactants, etc. [57, 58]. 

ChloroFiltr A polymeric sorbent for selective removal of chlorophyll from acetonitrile extracts without loss of polar aromatic pesticides. It is designed to replace GCB for the efficient removal of chlorophyll without loss of planar analytes. 

GCB Is a strong sorbent for removing pigments, polyphenols and other polar compounds. Examples of planar (polar aromatic) pesticides which may be removed chlorothalonil, coumaphos, hexachlorobenzene, thiabendazole, terbufos and quintozene. 

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