Anilide herbicide

Anilide herbicides are metabolized in plants via cleavage of acylamide moiety. 

Wi = amount of anilide herbicides for Vi read from calibration curve (ng)... 

Vryzas Z, Papadopoulou-Mourkidou E. Determination of triazine and chloroacet-anilide herbicides in soils by microwave-assisted extraction (MAE) coupled to gas chromatographic analysis with either GC-NPD or GC-MS. J. Agric. Food Chem. 2002 50 5026-5033. 

The most important substituted anilide herbicides (Fig. 10, Table 3) are Propanil,Propachlor,and Alachlor [43,151,175-178]. 

Bartha, R. Biochemical transformations of anilide herbicides in soil, J. Agric. Food Chem., 16(4) 602-604, 1968. 

Immunoassays have been used for the anilide herbicide alachlor, although initial assays were marred by false positives from the sulfonate metabolite in view of its greater water solubility and apparent persistence, a specific ELISA method was developed and used to carry out a widespread screening for both alachlor and the sulfonate metabolite (Thurman et al. 1996). Although sample preparation is considerably less complex than that used for conventional chemical analysis, confirmation of the identity of the analytes is obligatory. 

Benzoylprop-ethyl (31) and flamprop-isopropyl (32), two anilide herbicides selective in cereals with specific efficiency for the control of wild oat Avena spp.), have been developed in the research latoratories of the Shell Research Ltd. 

Substituted aromatic amines have been widely used in the chemical industry as intermediates in the production of dyes, pesticides, pharmaceuticals, paints, etc. They may be released into the environment directly as a result of industrial discharge form factories or indirectly as a result of degradation of phenylcarbamates, phenylurea and anilide herbicides, and azodyes. Chromatographic separation and quantification of primary amines is hampered by their polarity that can cause tailing and irreversible adsorption. Aromatic primary amines were derivatized to 7/-allyl-7/ -arylthioureaby... 

The movement of the substituted anilide herbicides in soils has not been reported, but weed scientists found that the compounds, alachlor and propachlor, perform better in high organic soils and poorer in coarse textured soils than many other chemicals. This is generally attributed to the relatively high water solubilities and low adsorptivities of the chemicals. Stickler et ah 342) found that soil incorporation of alachlor and propachlor did not improve their effectiveness over surface applications. 

Sunlight irradiation of an aqueous solution or suspension of the anilide herbicide, propanil (3, 4 -dichloropropionanilide), provided propionic acid and 3,4-dichloroaniline (and other anilines) as major intermediate products (38). Propanil, otherwise quite stable in neutral aqueous solution in the dark, apparently underwent a light-energized hydrolysis. 

Anilide herbicides constitute a group of compounds whose degradation occurs mainly through hydrolysis with formation of an acidic moiety, easily consumed by microorganisms. 

Sherma, J., and Boymel, J. (1983). Densitometric quantification of urea, carbamate, and anilide herbicides on Cig reversed phase thin layers using Bratton-Marshall reagent. J. Liq. Chromatogr. 6 1183-1192. 

Twelve carbamate, urea, and anilide herbicides investigated in water and soil samples were detected with Bratton-Marshall reagent after separation on KC g reversed-phase TLC plates. These pesticides produce aromatic amines after acidic hydrolysis. These primary aromatic amines could be diazotized and detected by azo-coupling reactions giving azo-dyes. After develc ment plates were sprayed with 6 N ethanolic HCl and heated at 180 C for 10 min. After cooling they were sprayed with NaN02 solution and later with AM-naphthyl-ethylenediamine dihydrochloride solution. The colored spots were evaluated by densitometry at nanogram levels (147). 

Another group of anilide herbicides is exemplified by propanil, whose mode of action is quite different from that of the chloroacetanilides. Members of this large class of compounds, which also includes various ureas and carbamates, affect the photosynthesis apparatus of the plant. They will be discussed in more detail later. 

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