Interaction of Fluazifop with Al-, Fe3+-, and Cu2+-Saturated Montmorillonite

G. Micera1, A. Pusino2, C. Gessa2 and S. Petretto2
1 Dipartimento di Chimica, Università di Sassari Via Vienna 2, 07100 Sassari, Italy
2 Istituto di Chimica Agraria, Università di Sassari Via E. de Nicola 10, 07100 Sassari, Italy

Abstract: The adsorption of the pesticide Fluazifop, (RS)-2-[4-[[(5-trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid, on homoionic Cu2+-, Fe3+-, and Al-bentonites was investigated by infrared and electron spin resonance spectroscopy. For comparison, the binary complexes of the acid containing the above ions were prepared and characterized. On the whole, the results show that the interaction of the acid with the clay may have involved both the protonation of the pyridine nitrogen atom, due to a proton transfer from the acid metal-bound water, and the formation of direct bonds between the carboxylate groups and the exchange cations. The extent of these interactions was dependent on the nature of the metal ions, the Cu ions being more effective in producing CHCl3-extractable neutral carboxylate complexes, while Al and Fe favored the formation of species bearing protonated nitrogen atoms and undissociated carboxyl groups.

Key Words: Adsorption • Electron spin resonance • Fluazifop • Infrared spectroscopy • Interlayer cations • Pesticide

Clays and Clay Minerals; August 1988 v. 36; no. 4; p. 354-358; DOI: 10.1346/CCMN.1988.0360410
© 1988, The Clay Minerals Society
Clay Minerals Society (www.clays.org)