Montmorillonite Functionalized with Pralidoxime As a Material for Chemical Protection against Organophosphorous Compounds

Abstract

Montmorillonite K-10 functionalized with α-nucleophilic 2-pralidoxime (PAM) and its zwitterionic oximate form (PAMNa) is introduced as a versatile material for chemical protection against organophosphorous (OP) compounds such as pesticides and chemical warfare agents (CWA). Upon inclusion into the montmorillonite interlayer structure, the pyridinium group of PAMNa is strongly physisorbed onto acidic sites of the clay, leading to shrinking of the interplanar distance. Degradation of diethyl parathion by PAMNa-functionalized montmorillonite in aqueous-acetonitrile solutions occurred primarily via hydrolytic conversion of parathion into diethylthio phosphoric acid, with the initial stages of hydrolysis observed to be pseudo-first-order reactions. Hydrolysis catalyzed by the clay intercalated by PAMNa was 10- and 17-fold more rapid than corresponding spontaneous processes measured at 25 and 70 °C, respectively. Hydrolytic degradation of diisopropyl fluorophosphate (DFP), a CWA simulant, was studied on montmorillonite clay functionalized by PAMNa and equilibrated with water vapor at 100% relative humidity by ³¹P high-resolution magic angle spinning NMR and was observed to be rather facile compared with the untreated montmorillonite, which did not show any DFP hydrolysis within 24 h. The incorporation of the functionalized clay particles into elastomeric film of polyisobutylene was shown to be a means to impart DFP-degrading capability to the film, with clay particle content exceeding 18 wt %.

Oxime functionality in surfactant self-assembly: An overview on combating toxicity of organophosphates

“…Tertiary oximes viz. monoisonitrosoacetone (MINA) and butane-2,3-dione monoxime (BDMO) are strong α-nucleophiles capable of hydrolyzing phosphate ester bonds [24,41]. Oximes such as pralidoxime, HI-6, and obidoxime have been used in the clinical practice to treat intoxication by certain OPCs for decades [42,43].…”

Intercalation and Exfoliation of Kaolinite with Sodium Dodecyl Sulfate

“…Recently, rubber/layered silicate nanocomposites have attracted extensive interest both in industry and academia due to the unique characteristics of nano-sized layered silicates, including their large surface area, high surface reactivity and relatively low cost [1][2][3][4]. The layered silicates used in rubbers can increase mechanical properties, improve thermal resistance and reduce gas permeability [2,5,6].…”

“…Kaolinite (Kaol), Al 2 Si 2 O 5 (OH) 4 , is a typical 1:1 layered dioctahedral aluminum silicate, which has been widely used as a filler in rubber [6,[14][15][16][17]. The layers of kaolinite are composed of SiO 4 tetrahedral sheets linked to AlO 2 (OH) 4 octahedral sheets.…”

“…The layers of kaolinite are composed of SiO 4 tetrahedral sheets linked to AlO 2 (OH) 4 octahedral sheets. The adjacent layers are tightly held together by hydrogen bonds between hydroxyl groups on the octahedral (aluminum) sheets and the tetrahedral (silicon) sheets.…”

Ultrasensitive electrochemical immunosensor for squamous cell carcinoma antigen detection using lamellar montmorillonite-gold nanostructures as signal amplification

“…Nanomontmorillonites belong to aluminosilicate clay minerals that could be converted to sodium montmorillonites (Na-Mont) by reacting with NaCl solution [13]. Na-Mont which consisted of layered structures have proved to be an ideal host due to their inherent advantages, such as large surface area, high cation exchange capacity, superior adsorption ability, nontoxicity and chemical stability and so on [14][15][16][17][18]. Based on the cation exchange ability of Na-Mont, many organic molecules with polar functional groups and ions can be intercalated into the interlayer space of montmorillonites [15].…”