The pesticide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (Diuron) immobilizedon silica gel surface

A route for 3-(3,4-dichlorophenyl)-1,l-dimethylurea (diuron) immobilization on silica gel was established after reacting at the first stage the precur sor silylant agent 3-trimethoxysilylpropylamine to the support. The pestici de was covalently bonded to available amine groups of the precursor, giving 1.03 mmol of amine per gram of silica. Infrared, C-13, and Si-29 NMR spect ra are in agreement with the proposed reaction between nitrogen of the amin e group of the previously anchored silica to carbon on the para-position of the aromatic ring of the pesticide. The immobilization is clearly affected by the presence or absence of disprotonating agent, to give 12.50 and 68.4 0% reaction yield, respectively; these results were confirmed through eleme ntal analysis. (C) zool Academic Press.