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001-es BibID:BIBFORM103329
035-os BibID:(WOS)000562983300018 (Scopus)85089709649
Első szerző:Simon Fruzsina (vegyész)
Cím:The chlorination of N-methyl amino acids with hypochlorous acid: kinetics and mechanisms / Fruzsina Simon, Eszter Kiss, Mária Szabó, István Fábián
Dátum:2020
ISSN:0893-228X
Megjegyzések:The formation and decomposition kinetics of N-chloro-N-methyl amino acids were studied to predict the fate and impact of these compounds in water treatment technologies and biological systems. These compounds form in fast second-order reactions between N-methyl amino acids and hypochlorous acid. The comparison of the activation parameters for the reactions of N-methyl substituted and nonsubstituted branched-chain amino acids reveals the transition-state features less organized structure and stronger bonds between the reactants in the reactions with the N-methyl derivatives. This is due to a combined positive inductive effect of the N-methyl group and the alkyl side chain as well as to the steric effects of the substituents. N-Methyl-N-chloro amino acids decompose much faster than the nonsubstituted compounds. The reaction rates do not depend on the pH, and the same final product is formed in the entire pH range. N-Chlorosarcosine is an exception, as it decomposes via competing paths, k(d)(obs) = k(d) + k(d)(OH)[OH-], yielding different final products. This feature is most likely due to the lack of an alkyl substituent on the alpha-carbon atom. Under physiological pH, aldehydes and methylamine form in these reactions, which are not particularly toxic.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Chemical Research In Toxicology. - 33 : 8 (2020), p. 2189-2196. -
További szerzők:Kiss Eszter (1995-) Szabó Mária (1991-) (vegyész) Fábián István (1956-) (vegyész)
Pályázati támogatás:GINOP-2.3.2-15-2016-00008
GINOP
K-124983
OTKA
ÚNKP-19-3
Egyéb
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DOI
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2.

001-es BibID:BIBFORM062694
Első szerző:Szabó Mária (vegyész)
Cím:Decomposition of N-Chloroglycine in Alkaline Aqueous Solution: Kinetics and Mechanism / Szabó Mária, Baranyai Zsolt, Somsák László, Fábián István
Dátum:2015
ISSN:0893-228X
Megjegyzések:The decomposition kinetics and mechanism of N-chloroglycine (MCG) was studied under very alkaline conditions ([OH-] = 0.01-0.10 M). The absorbance change is consistent with two consecutive first-order processes in the 220-350 nm wavelength range. The first reaction is linearly dependent on [OH-] and interpreted by the formation of a carbanion from MCG in an equilibrium step (KOH) and a subsequent loss of chloride ion from this intermediate: kobs1 = KOH k1 = (6.4 ? 0.1) ? 10-2 M-1 s-1, I = 1.0 M (NaClO4), and T = 25.0 ?C. The second process is assigned to the first-order decomposition of N-oxalylglycine, which is also formed as an intermediate in this system: kobs2 = (1.2 ? 0.1) ? 10-3 s-1. Systematic 1H and 13C NMR measurements were performed in order to identify and follow the concentration changes of the reactant, intermediate, and product. It is confirmed that the decomposition proceeds via the formation of glyoxylate ion and produces N-formylglycine as a final product. This compound is stable for an extended period of time but eventually hydrolyses into formate and glycinate ions. A detailed mechanism is postulated which resolves the controversies found in earlier literature results.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Chemical Research in Toxicology. - 28 : 6 (2015), p. 1282-1291. -
További szerzők:Baranyai Zsolt (1977-) (vegyész) Somsák László (1954-) (vegyész) Fábián István (1956-) (vegyész)
Pályázati támogatás:NK 105156
OTKA
TÁMOP-4.2.2.A-11/1/KONV-2012-0043
TÁMOP
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DOI
Intézményi repozitóriumban (DEA) tárolt változat
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