Haloacetic acid

An electronegative substituent particularly if it is attached to the a carbon increases the acidity of a carboxylic acid As the data m Table 19 2 show all the mono haloacetic acids are about 100 times more acidic than acetic acid Multiple halogen sub stitution increases the acidity even more trichloroacetic acid is 7000 times more acidic than acetic acid ... 

Removal of Refractory Organics. Ozone reacts slowly or insignificantly with certain micropoUutants in some source waters such as carbon tetrachloride, trichlorethylene (TCE), and perchlorethylene (PCE), as well as in chlorinated waters, ie, ttihalomethanes, THMs (eg, chloroform and bromoform), and haloacetic acids (HAAs) (eg, trichloroacetic acid). Some removal of these compounds occurs in the ozone contactor as a result of volatilization (115). Air-stripping in a packed column is effective for removing some THMs, but not CHBr. THMs can be adsorbed on granular activated carbon (GAG) but the adsorption efficiency is low. 

To synthesize the monoxacetam stmctures (Fig. 6), alkylation of A/-protected 1-hydroxyazetidinones (46) with the appropriate haloacetic acid derivatives provided (47). Alternatively, (47) could be prepared from the acycHc hydroxamate ester (48). Deprotection of (47) furnished the zwitterionic intermediate (49) [90849-16-4] CgH2QN204, which subsequendy underwent acylation using the C-3 aminothiazole oxime side chain to afford SQ 82,291 (45) also known as oximonam (37). 

Another example is the acidities of a series of carboxylic acids. It is known that the substitution effect on these compounds also depends on the environment. The behavior of the halo-substituted acetic acids is one of the prototype problems for the solvent effect on acidity The order in strength of the haloacetic acids in the gas phase is... 

Procedures to compute acidities are essentially similar to those for the basicities discussed in the previous section. The acidities in the gas phase and in solution can be calculated as the free energy changes AG and AG" upon proton release of the isolated and solvated molecules, respectively. To discuss the relative strengths of acidity in the gas and aqueous solution phases, we only need the magnitude of —AG and — AG" for haloacetic acids relative to those for acetic acids. Thus the free energy calculations for acetic acid, haloacetic acids, and each conjugate base are carried out in the gas phase and in aqueous solution. 

Haloacetic acids dichloroacetic acid (zero) trichloroacetic acid (0.3 mg/L). Monochloroacetic acid, bromoacetic acid, and dibromoacetic acid are regulated with this group but have no MCLGs. 

Molybdenum hexafluoride, in the presence of boron trifluonde, reacts with acetic acid and haloacetic acids at 130-160 °C to give respectively, 1,1,1 tri fluoroethane and 1,1 1 trifluorohaloetlianes in 60-89% yields [2d0, 241] Prolonged treatment of pyridine mono and dicarboxylic acids with an excess of molybdenum hexafluoride at elevated temperatures provides the respective mono-and bis(trifluoromethyl)pyridines in good yields [241] (equation 127)... 

This reaction is illustrative of a general procedure for the alkylation of active methylene functions in the presence of concentrated aqueous alkali catalyzed by tetraalkylammonium salts. This catalytic method has been used to alkylate arylacetonitriles with monohaloalkanes,2 dihaloalkanes,3 a-chloroethers,4 chloronitriles,.5 haloacetic acid esters,6 and halonitro aromatic compounds.7 It has also been used to alkylate ketones,8 lf/ indene,9 9i/-fluorene,ll) and the Reissert compound.11 The reaction is inhibited by alcohols and by iodide ion.2... 

Frank H, H Scholl, D Renschen, B Rether, A Laouedj, Y Norokorpi (1994) Haloacetic acids, phytotoxic secondary air pollutants. Environ Sci Pollut Res 1 4-14. 

Hashimoto S, T Azuma, A Otsuki (1998) Distribution, sources, and stability of haloacetic acids in Tokyo Bay, Japan. Environ Toxicol Chem 17 798-805. 

Potential applications of vitamin Bi2 in electrocatalytic degradation of dibromide and a-haloacetic acid pollutants has been demonstrated in aqueous buffers303,304 and in surfactant-stabilized emulsions.305 Electroreductive dehalogenations in water and microemulsions were also efficiently catalyzed by a vitamin Bi2 derivative grafted onto a polylysine-coated electrode.306... 

Hall-Petch relationship, 13 497 Haloacetic acids (HAAs), removal from drinking water, 17 806—807 Haloacetones, 1 163 Haloalkylating agents, 12 167 Haloalkylation, 12 166-168 Haloalkylbenzenes, intramolecular alkylation of, 12 169 IV-Halo-a-amino acids, 13 107 Haloaromatics, 13 573 Halobenzenes, as Friedel-Crafts arylating agents, 12 171 Halobismuthines, 4 28-29 Haloboration, 14 270 Halobrom (BCDMH,... 

B. Pauli and L. Barron, Using ion chromatography to monitor haloacetic acids in drinking water a review of current technologies. J. Chromatogr.A 1046 (2004) 1-10. 

The electroreductive dehalogenation of a-haloacetic acids has been achieved with cobalamin [387]. The hydrophobic vitamin B12 Co complex immobilized on a glassy carbon electrode (252) may catalyze the electrochemical carbon-skeleton rearrangements of... 

Ahrer, W., and Buchberger, W. (1999). Determination of haloacetic acids by the combination of nonaqueous capillary-electrophoresis and mass-spectrometry. Fresenius J. Anal. Chem. 365, 604-609. 

Determination of Haloacetic Acids in Drinking Water by LLE, Derivatization, and GC with ECD... 

Determination of Haloacetic Acids and Dalapon in Drinking Water by Ion-Exchange LSE and GC widi ECD... 

IB Micro LLE GC Method (Haloacetic acids and Trichlorophenol)... 

Total THMs (chloroform, bromodichloromethane, chlorodibromomethane, bromoform 5 Haloacetic acids (chloro-, bromo-, dichloro-, dibromo-, trichloroacetic acid)... 

GC/electron capture detection (ECD) is also used to measure DBFs. In particular, EFA Method 552.2 and 552.3 are commonly used to measure haloacetic acids in drinking water [156, 157]. ECD is very sensitive toward halogenated compounds and allows low-level detection for HAAs (0.012-0.17 pg/L detection limits for EFA Method 552.3). 

Hunter ES III, Rogers EH, Schmid JE, Richard A (1996) Comparative effects of haloacetic acids in whole embryo culture. Teratology 54 57-64... 

Cardador MJ, Gallego M (2011) Haloacetic acids in swimming pools swimmer and worker exposure. Environ Health Perspect 118 1545-1550... 

Munch DJ, Munch JW, Pawlecki AM (1995) EPA Method 552.2. Determination of haloacetic acids and dalapon in drinking water by liquid-liquid extraction, derivatization and gas chromatography with electron capture detection. U.S. EPA, Cincinnati, OH, Available at http //www.caslab.com/EPA-Methods/PDF/552 2.pdf... 

Ells B, Barnett DA, Purves RW, Guevremont R (2000) Detection of nine chlorinated and brominated haloacetic acids at part-per-trillion levels using ESI-FAIMS-MS. Anal Chem 72 (19) 4555 559... 

Gabryelski W, Wu F, Froese KL (2003) Comparison of high-field asymmetric waveform ion mobility spectrometry with GC methods in analysis of haloacetic acids in drinking water. Anal Chem 75(10) 2478-2486... 

Here we discuss several examples of the multicomponent processes involving aminoazoles, aldehydes, and other organic components such as mercaptoacids, haloacetic acids and their ester, a,p-unsaturated imines, etc., which were not incorporated into the previous two sections of the review. 

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