Immobilization of the pesticide 2,4-dichlorophenoxyacetic acid on a silicagel surface

A route for the immobilization of 2,4-dichlorophenoxyacetic acid (2,4-D) on silica gel has been developed. In the first step the precursor was prepare d by reacting the silylating agent 3-(trimethoxysilyl)propylamine with sili ca gel. Nitrogen analysis of this anchored compound showed the presence of 1.16 mmol of amine groups per gram of support. The herbicide was covalently bonded to the amine groups previously anchored onto silica gel. Infrared, [C-13] and [Si-29] NMR spectra supported the reaction between the nitrogen of the amine group of the anchored silica with the carbon on the para-posit ion of the aromatic ring of 2,4-D. The reaction yield, 90.3%, was confirmed through elemental analysis. (C) 2000 Society of Chemical Industry.