Herbicides chlorine-containing

The polarographic and voltammetric determination of chlorinated compounds, S-triazines, 2,4-AD-herbicides, nitro-containing pesticides, paraquat, diquat, carbamate pesti-... 

TABLE 3.11. Major Chlorine Containing Herbicides, Fungicides, and Insecticides with Regional Importance... 

The success of DDT in 1940s and 1950s led to a development of aU kinds of chlorine-containing organic compounds for pesticides, herbicides, and disinfectants. Many of them were introduced as commercial products, and used widely. Some of those compounds are shown in Fig. 16.1 along with DDT. These seven compounds (except t ,p-DDT) are often labeled as dirty seven for their toxic effects. 

Oxidation of triazine herbicides with chlorine and chlorine dioxide has been widely studied [105-108]. In the case of sulfur-containing triazines, oxidation occurs mainly via cleavage of the weakened R-S-CH3 bond rather than by addition of chlorine. Reactions of S-triazines with chlorine are faster than with chlorine dioxide, and form sulfoxide, sulfone, and a sulfone hydrolysis product. Chlorination with chlorine dioxide only produced sulfoxide [108]. Lopez et al. identified the formation of sulfonate esters during the chlorination of ametryn and terbutryn [106, 107]. Triazine DBFs identified by Brix et al. exhibited higher toxicities than the parent compounds [105]. Similar to triazines, clethodim, a cyclohexanedione herbicide, is oxidized by hypochlorite and chloramines to clethodim sulfoxide and then to sulfone [109]. 

Chlorination of waters containing two phenylurea-type herbicides, isoproturon and diuron, results in the formation of THMs. The reaction of the phenylurea-type herbicide isoproturon with chlorine produced compounds that still contained the aromatic ring of the herbicide with the urea side-chain unmodified. The formation of chlorinated and brominated derivatives was related to the bromide concentration present in the water [113]. 

Uses. As a reagent for albumin detection in making herbicides. It is found as a by-product after chlorination of water containing humic materials. 

The vendor indicates the technology can treat waste streams containing solvents, petroleum distillates, chlorinated solvents, pesticides and herbicides, as well as phenolic wastes, pulping liquors, municipal sewage, and industrial sludges. 

Micro-contaminants are present in chemicals at concentrations <1% of the mass. A very important class of micro-contaminants in a number of chlorinated chemicals is the chlorinated dioxins and furans. Dioxins are now classified as POPs [43], but in the late 1960s and early 1970s [201] became widely known when they were discovered to be micro-contaminants of 2,4,5-T-containing herbicides. There are numerous sources of dioxins but the most important source from synthetic chemicals is from... 

Chlorinated aromatic compounds are hazardous compounds that result from various industrial and agricultural activities. Water disinfection, waste incineration, and uncontrolled use of biocides are the major sources of chlorinated aromatics in the environment. Chlorinated compounds are also formed as subproducts of the biochemical reactions of herbicides containing chlorophe-noxy compounds. Treatment of chlorinated compounds has been studied using biological treatment, adsorption, air stripping, and incineration. Biodegradation of chlorinated compounds is a slow process that is ineffective for extremely low concentrations. Air stripping and adsorption simply trans-... 

In general, workers involved in the manufacture of 2,4,5-TCP and subsequent products were exposed to far greater levels of 2,3,7,8-TCDD than those involved in the handling and application of chlorinated pesticides containing CDDs. Current serum lipid levels of 2,3,7,8-TCDD in a small number of U.S. Air Force veterans who were directly involved in the aerial spraying of herbicides (Agent Orange contaminated with 2,3,7,8-TCDD) in Vietnam as part of Operation Ranch Hand,... 

Dinitroaniline herbicides. Trifluralin (Treflan ), a 4-trifluoromethyl substituted 2,6-dinitroaniline derivative, was the first main fluorine-containing herbicide to be marketed, with 18,000 tons sold in 1982 in the United States alone [16]. Trifluralin, which was introduced in 1960 by Eli Lilly, is a pre-emergence herbicide used in soybean for the control of a variety of grass and broadleaf weeds [17]. It is prepared from the nitration of 4-chlorobenzotrifluoride, followed by nucleophilic displacement of chlorine with di-n-propyl amine (Fig. 3). Following the success of trifluralin, a number of related A/,A/-dialkyl 4-trifluoromethyl 2,6-dinitroaniline herbicides were later introduced [18]. 

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