Abstract:

A simple strategy for the modification of polymers having hydroxyl or amino groups on their surfaces by o-iodoxybenzoyl (IBX) groups is described. The synthetic route involves modification of 5-hydroxy-2-iodobenzoic acid with 3-isocyanatopropyltriethoxysilane in nonaqueous solvent followed by conjugation of the resulting triethoxysilanylpropylcarbamoyloxyiodobenzoic acid with the −OH groups of the polymers via sol–gel reaction in the presence of water. The formation of silica conjugated to the polymer creates organic–inorganic particles. The iodobenzoic groups on the particle surfaces are further oxidized by Oxone tetrabutylammonium salt into IBX. The IBX-modified poly(vinyl alcohol) and microcrystalline cellulose were shown to be capable of hydrolyzing diisopropyl fluorophosphate (DFP), an analogue of sarin and soman, at pH 7.4 with the apparent second-order rate constants (k′′) of 4.6 × 10⁻² and 2.7 × 10⁻² M⁻¹ s⁻¹, respectively. The IBX−cellulose and IBX−PVA suspensions accelerated chlorpyrifos degradation 26- and 122-fold compared to the corresponding unmodified cellulose and PVA suspensions, respectively. Approximately 43-fold acceleration of the chlorpyrifos oxon degradation was measured in the IBX−PVA suspensions compared to the corresponding PVA solutions. The IBX-modified particles were capable of oxidizing the thiophosphate (PS) group to the corresponding oxon (PO). The developed modification route is appropriate for a wide variety of surfaces for chemical defense applications.