Chlorinated aliphatic acids

This group of pesticides comprises different families of chemicals with her-bicidal action including substituted phenols, chlorinated aliphatic acids, chloro-phenoxy alkanoic acids, and substituted benzoic acids, which possess carboxyl or phenolic functional groups capable of ionization in aqueous media to yield anionic species [47,151,168-170]. 

Figure 2 shows a simplified process flow diagram for halogenated aliphatic acid production facilities [8]. Halogenated aliphatic acids include chlorinated aliphatic acids and their salts, for example, TCA, Dalapon, and Fenac herbicides. Chlorinated aliphatic acids can be prepared by nitric acid oxidation of chloral (TCA) or by direct chlorination of the acid. The acids can be sold as mono- or dichloro acids, or neutralized to an aqueous solution with caustic soda. The neutralized solution is generally fed to a dryer from which the powdered product is packaged. 

Foy, C.L. (1976) The chlorinated aliphatic acid. In Herbicides Chemistry, Degradation and Mode of Action, Marcel Dekker, New York. 

Dalapon, a chlorinated aliphatic acid, was introduced by Dow Chemical in 1953 (Fig. 3). It is a grass killer, controlling tough perennial grasses such as johnsongrass, bermudagrass, and quackgrass. It possesses almost no crop selectivity. 

Eight of the nine compounds are chlorinated phenoxyadds dalapon is a chlorinated aliphatic acid. The positive ion thermospray mass spectra of these pesticides are summarized in Table I. The base peak in all cases is the (M+NH4)+ ion for 2,4-DB the (M+H) ion is present No ions were detected for dalapon. Since the protonated molecule is present for 2,4-DB this compound has the highest apparent proton affinity among these herbicides. 

The biochemical mode of action of dalapon has not been unequivocally elucidated. The protein precipitating action of chlorinated aliphatic acids, hence of dalapon, is known (Redemann and Hamaker, 1954), and it has also been proved by the investigations of Kemp et al. (1969) that the acid form of dalapon is able to form a hydrogen bond with the amide group of the protein molecule, so that this mechanism, in blocking enzyme activity, may be the cause of the phytotoxic action. Hilton et al. (1959) proved that dalapon inhibits the pantothenic acid synthesis of plants. 

S02C12 does not chlorinate aliphatic acids or acid chlorides appreciably in the dark and in the absence of catalysts if, however, a halogen carrier is introduced, the a-chloro acids are formed. 

Behaviour and fate of chlorinated aliphatic acids in soil. 

A stable material in humid conditions at temperatures up to 105°C, polyphenylene oxide is resistant to most aqueous solutions of acids and alkalis but is attacked by many organic solvents, particularly by aromatics and chlorinated aliphatics. 

Fluorescein paraffin derivatives, waxes, hydrocarbons [140,141] aliphatic acids [142] hydroquinone and chlorinated derivatives [143] isoprenoids, quinones [111,144] oxathizine fungicides [145] barbiturates, phenothiazines [146]... 

The action of chlorine on the aliphatic acids takes place in presence of sunlight, also on the addition of small quantities of the halogen-carriers, iodine, sulphur, and red phosphorus. By the action ofiodine, I Cl is formed, which decomposes moie readily than the molecule of chlorine, and hydriodic acid is libciatcd,... 

New Jersey 08360. A Dimroth condenser is recommended for use with refluxing liquids that boil up to 160°. Since the points of sealing are situated above the zone with a high temoerature gradient, the risk of cracking from thermal stress is minimized. The a-chlorination of aliphatic acids by this procedure is usually carried out at 110-140° (see Table I). The submitters circulated ice-cold water through the condenser. 

Driscoll TR, Hamdan HH, Wang G, et al. 1992. Concentrations of individual serum or plasma bile acids in workers exposed to chlorinated aliphatic hydrocarbons. Br J Ind Med 49 700-705. 

Figure 2 General process flow diagram for halogerated aliphatic acid production facilities. Major processes for pesticide production, including chlorination, cooling, crystallization, centrifying, and drying. The salt of the pesticide is produced by another route (from Ref. 8).

Weather- Sunlight Ozone NaOH Acid Degreasers Chlorinated Aliphatic ... 

TEES is capable of treating several classes of organic compounds, including aliphatics, aromatics, chlorinated aliphatics and aromatics, polycyclic aromatics, cyanides, amines, phenolics, organic acids, and ketones. 

The tetraiodide is slightly soluble in acetone and in ethanol (about 1 gm PoI4/liter) but is insoluble in dilute mineral acids and in ethers, aliphatic acids and hydrocarbons. It is slowly hydrolyzed by water and by concentrated alkali, the white product presumably being a basic iodide, and is decomposed by chlorine, hypochlorite, nitrite, and hot concentrated nitric acid. It does not react with ammonia gas but is reduced to the metal on heating in hydrogen sulfide. Suspensions of the tetraiodide in 0.1 N hydriodic acid are unaffected by hydrazine or sulfur dioxide, even on boiling, and there is no evidence for a diiodide. 

Use of the resins with samples containing free chlorine residual is not recommended. Cheh (35) suggested that chlorine may produce mutagenic artifacts on XAD-4. Our experiment with 2-mg/L chlorine residual appeared to promote the release of irreversibly adsorbed spiked standards Six model compounds were recovered at levels several times higher than those observed in normal blank runs. In addition, many resin artifacts were eluted after exposure to this chlorine level, primarily aromatic and aliphatic acids, aldehydes, and ketones. Stoichiometric dechlorination (ferrous ion) is therefore recommended in order to avoid cross contamination between samples and inclusion of undesirable resin artifacts in the residue to be bioassayed. 

Kohler-Staub, D. Kohler, H-P. E. (1989). Microbial degradation of / -chlorinated four-carbon aliphatic acids. Journal of Bacteriology, 171, 1428-34. 

Noryl is a rigid dimensionally stable material. Dimensional stability results from a combination of low mold shrinkage, low coefficient of thermal expansion (5.9 x 10-5 per° C), good creep resistance (0.6—0.8% in 300 h at 13.8 MPa (2000 psi)), and the lowest water absorption rate of any of the engineering thermoplastics (0.07% in 24 h at room temperature). Noryl resins are completely stable to hydrolysis. They are not affected by aqueous acids or bases and have good resistance to some oiganic solvents, but they are attacked by aromatic or chlorinated aliphatic compounds. 

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