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

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.