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Registro Completo |
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Biblioteca(s): |
Embrapa Instrumentação. |
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Data corrente: |
22/12/1999 |
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Data da última atualização: |
22/12/1999 |
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Autoria: |
SPOSITO, G.; MARTIN-NETO, L.; YANG, A. |
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Afiliação: |
University of California-Ecosystem Sciences Division; EMBRAPA-CNPDIA. |
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Título: |
Atrazine complexation by soil humic acids. |
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Ano de publicação: |
1996 |
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Fonte/Imprenta: |
Journal of Environmental Quality, Madison, v.25, n.6, p.1203-1209, Nov./Dec. 1996. |
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Idioma: |
Inglês |
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Conteúdo: |
Atrazine complexation pathways with soil humic acid remain a controversial issue, in part because of the absence of direct spectroscopic information. Recent optical and magnetic resonance spectral data indicate that proton-transfer and, to a lesser extent, hydrogen bonding are as important as electron-transfer in the mechanisms of reaction between atrazine and humic acid, whereas other s-triazines appear to react more strongly by electron transfer mechanisms. Two representative temperate-zone humic acids were selected to probe the issue of complexation mechanisms more decisively. They were reacted at pH < 7 with 140mmol mE-3 atrazine solution under exclusion of light. Infrared and electron spin resonance spectra of the resulting products gave evidence for proton-transfer and, under certain conditions, electron-transfer reactions. The spectroscopic data were analyzed in terms of the molecular properties of humic acids and s-triazines. The analysis suggested a general guiding principle to characterize the complexation mechanisms of s-triazines with soil humic acids. Proton-transfer is favored (and electron-transfer is disfavored) for humic acids of high acidic functional group content and for s-triazines of low basicity. Electron-transfer mechanisms are favored for humic acids of low acidic functional group content and for s-triazines of high basicity. This principle illustrates the importance of specific molecular structure to understanding reactivity between the s-triazines and humic acids. MenosAtrazine complexation pathways with soil humic acid remain a controversial issue, in part because of the absence of direct spectroscopic information. Recent optical and magnetic resonance spectral data indicate that proton-transfer and, to a lesser extent, hydrogen bonding are as important as electron-transfer in the mechanisms of reaction between atrazine and humic acid, whereas other s-triazines appear to react more strongly by electron transfer mechanisms. Two representative temperate-zone humic acids were selected to probe the issue of complexation mechanisms more decisively. They were reacted at pH < 7 with 140mmol mE-3 atrazine solution under exclusion of light. Infrared and electron spin resonance spectra of the resulting products gave evidence for proton-transfer and, under certain conditions, electron-transfer reactions. The spectroscopic data were analyzed in terms of the molecular properties of humic acids and s-triazines. The analysis suggested a general guiding principle to characterize the complexation mechanisms of s-triazines with soil humic acids. Proton-transfer is favored (and electron-transfer is disfavored) for humic acids of high acidic functional group content and for s-triazines of low basicity. Electron-transfer mechanisms are favored for humic acids of low acidic functional group content and for s-triazines of high basicity. This principle illustrates the importance of specific molecular structure to understanding reactivity between the s-triazines ... Mostrar Tudo |
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Categoria do assunto: |
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Marc: |
LEADER 01920naa a2200145 a 4500
001 1026424
005 1999-12-22
008 1996 bl --- 0-- u #d
100 1 $aSPOSITO, G.
245 $aAtrazine complexation by soil humic acids.
260 $c1996
520 $aAtrazine complexation pathways with soil humic acid remain a controversial issue, in part because of the absence of direct spectroscopic information. Recent optical and magnetic resonance spectral data indicate that proton-transfer and, to a lesser extent, hydrogen bonding are as important as electron-transfer in the mechanisms of reaction between atrazine and humic acid, whereas other s-triazines appear to react more strongly by electron transfer mechanisms. Two representative temperate-zone humic acids were selected to probe the issue of complexation mechanisms more decisively. They were reacted at pH < 7 with 140mmol mE-3 atrazine solution under exclusion of light. Infrared and electron spin resonance spectra of the resulting products gave evidence for proton-transfer and, under certain conditions, electron-transfer reactions. The spectroscopic data were analyzed in terms of the molecular properties of humic acids and s-triazines. The analysis suggested a general guiding principle to characterize the complexation mechanisms of s-triazines with soil humic acids. Proton-transfer is favored (and electron-transfer is disfavored) for humic acids of high acidic functional group content and for s-triazines of low basicity. Electron-transfer mechanisms are favored for humic acids of low acidic functional group content and for s-triazines of high basicity. This principle illustrates the importance of specific molecular structure to understanding reactivity between the s-triazines and humic acids.
700 1 $aMARTIN-NETO, L.
700 1 $aYANG, A.
773 $tJournal of Environmental Quality, Madison$gv.25, n.6, p.1203-1209, Nov./Dec. 1996.
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Registro original: |
Embrapa Instrumentação (CNPDIA) |
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 | Acesso ao texto completo restrito à biblioteca da Embrapa Acre. Para informações adicionais entre em contato com cpafac.biblioteca@embrapa.br. |
Registro Completo
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Biblioteca(s): |
Embrapa Acre. |
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Data corrente: |
14/06/2010 |
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Data da última atualização: |
06/11/2023 |
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Tipo da produção científica: |
Artigo em Anais de Congresso |
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Autoria: |
AMARAL, E. F. do; BROWN, I. F. |
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Afiliação: |
EUFRAN FERREIRA DO AMARAL, CPAF-AC; IRVING FOSTER BROWN, UNIVERSIDADE FEDERAL DO ACRE. |
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Título: |
O papel da reserva extrativista nos ciclos biogeoquímicos no Acre. |
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Ano de publicação: |
1997 |
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Fonte/Imprenta: |
In: WORKSHOP THE BIOGEOCHEMICAL CONSEQUENCES OF LAND USE CHANGE IN THE WESTERN BRAZILIAN AMAZON BASIN, 1997, Cuiabá. Report... [Cuiabá]: Interamerican Institute for Global Change Research, 1997. |
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Páginas: |
3 p. |
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Idioma: |
Português |
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Palavras-Chave: |
Extrativismo. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 00553nam a2200133 a 4500
001 1855032
005 2023-11-06
008 1997 bl uuuu u00u1 u #d
100 1 $aAMARAL, E. F. do
245 $aO papel da reserva extrativista nos ciclos biogeoquímicos no Acre.$h[electronic resource]
260 $aIn: WORKSHOP THE BIOGEOCHEMICAL CONSEQUENCES OF LAND USE CHANGE IN THE WESTERN BRAZILIAN AMAZON BASIN, 1997, Cuiabá. Report... [Cuiabá]: Interamerican Institute for Global Change Research$c1997
300 $a3 p.
653 $aExtrativismo
700 1 $aBROWN, I. F.
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