Rapid Destruction of Two Types of Chemical Warfare Agent Simulants by Hybrid Polyoxomolybdates Modified by Carboxylic Acid Ligands

Abstract

Four chain-like hybrid compounds based on mixed carboxylic acid ligands-modified polyoxomolybdates, K2H[(H2O)4M][AsMo6O21(Ala)(PHBA)2]·nH2O 1–4 (M = Co, Ni, Zn, Mn; Ala = alanine; PHBA = p-hydroxybenzonic acid), were prepared and characterized by elemental analysis, IR spectroscopy, solid diffuse reflective spectroscopy, TG analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. Four isostructural compounds 1–4 not only represent the extended architectures constructed from two different organic ligands-modified polyoxometalates but also can rapidly catalyze the degradation of two chemical warfare agent simulants, 2-chloroethyl ethyl sulfide (CEES) and diethyl cyanophosphonate (DECP), at room temperature. The catalytic results were analyzed and confirmed by GC-FID, GC-MS, and 1HNMR techniques. Within 5 min, CEES was high-selectively oxidized to the corresponding nontoxic 2-chloroethyl ethyl sulfoxide (CEESO) using heterogeneous catalyst 1 with the oxidant H2O2 (conversion % = 98.5%, selectivity % > 99.9%). FTIR, PXRD techniques, and the following cycles also ascertained the stability and structural integrity of 1 in the oxidation reaction. Within 10 min, DECP can be almost entirely hydrolyzed to the nontoxic products catalyzed by 1 (conversion % = 99.0%). To our knowledge, they are in the rank of highly active catalysts for the degradation of CEES and DECP to date, accompanied by the advantages of steady reuse.