The adsorption of the herbicide imazamethabenz-methyl, a mixture of the two isomers methyl (+/-)-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-4-methylbenzoate (para isomer) and methyl(+/-)-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-methylbenzoate (meta isomer), from water onto Al3+-, Fe3+-, Ca2+-, K+- and Na+-montmorillonite was studied by analytical (HPLC) methods. The adsorption from an organic solvent was also investigated by spectroscopic (IR) and X-ray diffraction measurements. It was observed that, depending on the acidic properties of the exchangeable cations, two different mechanisms may take place. The first one, acting on Fe3+- and Al3+-clays, involves the protonation of the more basic nitrogen atom of imidazolinone ring of the herbicide because of a proton transfer from the acidic metal-bound water, followed by adsorption on the clay surfaces. In this case, the clay surfaces have greater affinity for the meta than the para isomer, due to the extra-stabilization of the meta protonated form by resonance. The second mechanism, taking place on Ca2+-, K+- and Na+-clays, is hydrogen-bond formation between the ester carbonyl group of the herbicide and hydration water metal ions and is not affected by the structure of the isomers.

ADSORPTION MECHANISMS OF IMAZAMETHABENZ-METHYL ON HOMOIONIC MONTMORILLONITE / PUSINO A; GELSOMINO A; GESSA C. - In: CLAYS AND CLAY MINERALS. - ISSN 0009-8604. - 43:3(1995), pp. 346-352. [10.1346/CCMN.1995.0430309]

ADSORPTION MECHANISMS OF IMAZAMETHABENZ-METHYL ON HOMOIONIC MONTMORILLONITE

PUSINO, Alba;
1995

Abstract

The adsorption of the herbicide imazamethabenz-methyl, a mixture of the two isomers methyl (+/-)-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-4-methylbenzoate (para isomer) and methyl(+/-)-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-methylbenzoate (meta isomer), from water onto Al3+-, Fe3+-, Ca2+-, K+- and Na+-montmorillonite was studied by analytical (HPLC) methods. The adsorption from an organic solvent was also investigated by spectroscopic (IR) and X-ray diffraction measurements. It was observed that, depending on the acidic properties of the exchangeable cations, two different mechanisms may take place. The first one, acting on Fe3+- and Al3+-clays, involves the protonation of the more basic nitrogen atom of imidazolinone ring of the herbicide because of a proton transfer from the acidic metal-bound water, followed by adsorption on the clay surfaces. In this case, the clay surfaces have greater affinity for the meta than the para isomer, due to the extra-stabilization of the meta protonated form by resonance. The second mechanism, taking place on Ca2+-, K+- and Na+-clays, is hydrogen-bond formation between the ester carbonyl group of the herbicide and hydration water metal ions and is not affected by the structure of the isomers.
ADSORPTION MECHANISMS OF IMAZAMETHABENZ-METHYL ON HOMOIONIC MONTMORILLONITE / PUSINO A; GELSOMINO A; GESSA C. - In: CLAYS AND CLAY MINERALS. - ISSN 0009-8604. - 43:3(1995), pp. 346-352. [10.1346/CCMN.1995.0430309]
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11388/49132
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? 17
social impact