- Formation of the haloacetic acids during ozonation and chlorination of water in warsaw waterworks (Poland)
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The results of the study of the HAAs formation in Water Works in Warsaw, Poland are presented. Water taken from Zegrzynskie Lake is characterized by elevated content of humic substances and algae bloom in hot seasons. The water is ozonated and chlorinated
- Dojlido, Jan,Zbiec, Edward,Swietlik, Ryszard
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- Reduction of haloacetic acids by Fe0: Implications for treatment and fate
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To predict the fate of haloacetic acids (HAAs) in natural or engineered systems, information is needed concerning the types of reactions that these compounds undergo, the rates of those reactions, and the products that are formed. Given that many drinking water distribution systems consist of unlined cast iron pipe, reactions of HAAs with elemental iron (Fe0) may play a role in determining the fate of HAAs in these systems. In addition, zerovalent iron may prove to be an effective treatment technology for the removal of HAAs from chlorinated drinking water and wastewater. Thus, batch experiments were used to investigate reactions of four trihaloacetic acids, trichloroacetic acid (TCAA), tribromoacetic acid (TBAA), chlorodibromoacetic acid (CDBAA), and bromodichloroacetic acid (BDCAA), with Fe0. All compounds readily reacted with Fe0, and investigation of product formation and subsequent disappearance revealed that the reactions proceeded via sequential hydrogenolysis. Bromine was preferentially removed over chlorine, and TBAA was the only compound completely dehalogenated to acetic acid. In compounds containing chlorine, the final product of reactions with Fe0 was monochloroacetic acid. Halogen mass balances were 95-112%, and carbon mass balances were 62.6-112%. The pseudo-first-order rate constants for trihaloacetic acid degradation were as follows: BDCAA (10.6 ± 3.1 h-1) > CDBAA (1.43 ± 0.32 h-1) ≈ TBAA (1.41 ± 0.28 h--1) ? TCAA (0.08 ± 0.02 h-1).
- Hozalski, Raymond M.,Zhang, Li,Arnold, William A.
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- A Straightforward Homologation of Carbon Dioxide with Magnesium Carbenoids en Route to α-Halocarboxylic Acids
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The homologation of carbon dioxide with stable, (enantiopure) magnesium carbenoids constitutes a valuable method for preparing α-halo acid derivatives. The tactic features a high level of chemocontrol, thus enabling the synthesis of variously functionalized analogues. The flexibility to generate magnesium carbenoids through sulfoxide-, halogen- or proton- Mg exchange accounts for the wide scope of the reaction. (Figure presented.).
- Monticelli, Serena,Urban, Ernst,Langer, Thierry,Holzer, Wolfgang,Pace, Vittorio
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supporting information
p. 1001 - 1006
(2019/01/30)
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- Liquid-phase oxidation of bromovinyl compounds with molecular oxygen
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Liquid-phase oxidation of bromovinyl compounds with the aim to obtain the corresponding α-bromo acids was studied.
- Bayatyan,Bayatyan,Saakyan
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p. 1849 - 1852
(2008/02/08)
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- Chemical and biological characterization of newly discovered iodoacid drinking water disinfection byproducts
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Iodoacid drinking water disinfection byproducts (DBPs) were recently uncovered in drinking water samples from source water with a high bromide/iodide concentration that was disinfected with chloramines. The purpose of this paper is to report the analytical chemical identification of iodoacetic acid (IA) and other iodoacids in drinking water samples, to address the cytotoxicity and genotoxicity of IA in Salmonella typhimurium and mammalian cells, and to report a structure-function analysis of IA with its chlorinated and brominated monohalogenated analogues. The iodoacid DBPs were identified as iodoacetic acid, bromoiodoacetic acid, (Z)- and (E)-3-bromo-3-iodopropenoic acid, and (E)-2-iodo-3-methylbutenedioic acid. IA represents a new class (iodoacid DBPs) of highly toxic drinking water contaminants. The cytotoxicity of IA in S. typhimurium was 2.9× and 53.5× higher than bromoacetic acid (BA) and chloroacetic acid (CA), respectively. A similar trend was found with cytotoxicity in Chinese hamster ovary (CHO) cells; IA was 3.2× and 287.5× more potent than BA and CA, respectively. This rank order was also expressed in its genotoxicity with IA being 2.6× and 523.3× more mutagenic in S. typhimurium strain TA100 than BA and CA, respectively. IA was 2.0× more genotoxic than BA and 47.2× more genotoxicthan CA in CHO cells. The rank order of the toxicity of these monohalogenated acetic acids is correlated with the electrophilic reactivity of the DBPs. IA is the most toxic and genotoxic DBP in mammalian cells reported in the literature. These data suggest that chloraminated drinking waters that have high bromide and iodide source waters may contain these iodoacids and most likely other iodo-DBPs. Ultimately, it will be important to know the levels at which these iodoacids occur in drinking water in order to assess the potential for adverse environmental and human health risks.
- Plewa, Michael J.,Wagner, Elizabeth D.,Richardson, Susan D.,Thruston Jr., Alfred D.,Woo, Yin-Tak,McKague, A. Bruce
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p. 4713 - 4722
(2007/10/03)
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- Microsomal oxidation of tribromoethylene and reactions of tribromoethylene oxide.
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Halogenated olefins are of interest because of their widespread use in industry and their potential toxicity to humans. Epoxides are among the enzymatic oxidation products and have been studied in regard to their toxicity. Most of the attention has been given to chlorinated epoxides, and we have previously studied the reactions of the mono-, di-, tri-, and tetrachloroethylene oxides. To further test some hypotheses concerning the reactivity of these compounds, we prepared tribromoethylene (TBE) oxide and compared it to trichloroethylene (TCE) oxide and other chlorinated epoxides. TBE oxide reacted with H(2)O about 3 times faster than did TCE oxide. Several hydrolysis products of TBE oxide were the same as formed from TCE oxide, i.e., glyoxylic acid, CO, and HCO(2)H. Br(2)CHCO(2)H was formed from TBE oxide; the yield was higher than for Cl(2)CHCO(2)H formed in the hydrolysis of TCE oxide. The yield of tribromoacetaldehyde was 0.4% in aqueous buffer (pH 7.4). In rat liver microsomal incubations containing TBE and NADPH, Br(2)CHCO(2)H was a major product, and tribromoacetaldehyde was a minor product. These results are consistent with schemes previously developed for halogenated epoxides, with migration of bromine being more favorable than for chlorine. Reaction of TBE oxide with lysine yielded relatively more N-dihaloacetyllysine and less N-formyllysine than in the case of TCE oxide. This same pattern was observed in the products of the reaction of TBE oxide with the lysine residues in bovine serum albumin. We conclude that the proposed scheme of hydrolysis of halogenated epoxides follows the expected halide order and that this can be used to rationalize patterns of hydrolysis and reactivity of other halogenated epoxides.
- Yoshioka, Tadao,Krauser, Joel A,Guengerich, F Peter
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p. 1414 - 1420
(2007/10/03)
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- Effects of bromide on the formation of THMs and HAAs
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The role of bromide in the formation and speciation of disinfection by-products (DBPs) during chlorination was investigated. The molar ratio of applied chlorine to bromide is an important factor in the formation and speciation of trihalomethanes (THMs) and halogenacetic acids (HAAs). A good relationship exists between the molar fractions of THMs and the bromide incorporation factor. The halogen substitution ability of HOBr and HOCl during the formation of THMs and HAAs can be determined based on probability theory. The formation of HAAs, and their respective concentrations, can also be estimated through use of the developed model.
- Chang,Lin,Chiang
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p. 1029 - 1034
(2007/10/03)
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- Synthesis of isotopically labelled L-phenylalanine and L-tyrosine
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A synthetic route to stable-isotope-substituted L-phenylalanine is presented, which allows the introduction of 13C, 15N, and deuterium labels at any position or combination of positions. For labelling of the aromatic ring, a synthetic route to ethyl benzoate (or benzonitrile) has been developed, based on the electrocyclic ring-closure of a 1,6-disubstituted hexatriene system, with in situ aromatization by elimination of one (amino) substituent. Several important (highly isotopically enriched) synthons have been prepared, namely benzonitrile, benzaldehyde, ethyl benzoate, and ethyl diphenyloxyacetate. Labelled L-phenylalanines have been synthesized from both aromatic precursors by initial conversion into sodium phenylpyruvate and subsequent transformation of this intermediate into the L-α-amino acid by an enzymatic reductive amination reaction. In this manner, highly enriched phenylalanines are obtained on the 10-gram scale and with high enantiomeric purities (≥ 99% ee). The method has been validated by the synthesis of [1'13C]-L-Phe and [2-D]-L-Phe. In addition, two methods are described for the introduction of isotopes into L-tyrosine starting from the isotopically enriched precursors benzonitrile and ethyl benzoate.
- Raap, Jan,Nieuwenhuis, Saskia,Creemers, Alain,Hexspoor, Sander,Kragl, Udo,Lugtenburg, Johan
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p. 2609 - 2621
(2007/10/03)
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- Degradation of Lactic Acid and Pyruvic Acid in Belousov-Zhabotinskii Reactions
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The temporal degradation of the Belousev-Zhabotinskii substrates lactic acid, pyruvic acid, bromo- and dibromo pyruvic acid is investigated.The only final product of non-brominated substrates is acetic acid.From brominated educts only brominated acetic acids result.The concentrations of the stable products are determined as a function of time.The gross reactions are mainly based on simple consecutive first order reactions.For the pyruvic acid rate constants are determined. - Keywords: Belousov-Zhabotinskii Reaction, Lactid Acid, Pyruvic Acid, Bromo Pyruvic Acid
- Blume, Ruediger,Wiechoczek, Dagmar,Meier, Heinrich,Wedekind, Frank
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p. 598 - 608
(2007/10/02)
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- MERCURATION OF 2-ALKYL-1,3-DIOXOLAN-2-YLIUM SALTS: NEW METHOD FOR THE SYNTHESIS OF α-MERCURIO CARBOXYLIC ACIDS
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In the mercuration of 2-alkyl-1,3-dioxolan-2-ylium perchlorates with mercury acetate of trifluoroacetate high yileds of mono-, di-, and tri-α-mercurio derivatives of carboxylic acids wre obtained, depenging on the proportions of the reacting substrates.
- Boev, V. I.,Dombrovskii, A. V.
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p. 1927 - 1930
(2007/10/02)
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