Dissipation of molinate in a rice field

Abstract

The dissipation of the herbicide molinate (S-ethyl hexahydro-1H-azepine-1-carbothioate) in a California rice field was investigated. Laboratory experiments indicated that while dilute aqueous solutions of molinate were stable in sunlight, irradiation in the presence of tryptophan resulted in decomposition primarily to 1-[(ethylsulfinyl)carbonyl]hexahydro-1H-azepine, S-ethyl hexahydro-2-oxo-1H-azepine-1-carbothioate, and hexamethyleneimine. Analysis for molinate and its degradation products at sub-ppm levels in water, soil, and air samples collected from a commercially treated field, together with laboratory studies, showed that volatilization of molinate from water was the primary mode of dissipation, although photodecomposition products were present in field water. © 1977, American Chemical Society. All rights reserved.