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Nanocrystalline Metal Oxides as Destructive Adsorbents for Organophosphorus Compounds at Ambient Temperatures
Author(s) -
Rajagopalan Shyamala,
Koper Olga,
Decker Shawn,
Klabunde Kenneth J.
Publication year - 2002
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20020603)8:11<2602::aid-chem2602>3.0.co;2-3
Subject(s) - paraoxon , nanocrystalline material , adsorption , reactivity (psychology) , chemisorption , chemistry , metal , oxide , monolayer , inorganic chemistry , organic chemistry , crystallography , medicine , biochemistry , enzyme , alternative medicine , pathology , acetylcholinesterase
Nanocrystals of magnesium oxide react with organophosphorus compounds at room temperature by dissociative chemisorption, which we term “destructive adsorption”. This process involves cleavage of PO and PF bonds (but not PC bonds) and immobilization of the resultant molecular fragments. These ultrafine powders have unusual crystalline shapes and possess high surface concentrations of reactive edge/corner and defect sites, and thereby display higher surface reactivity, normalized for surface area, than typical polycrystalline material. This high surface reactivity coupled with high surface area allows their use for effective decontamination of chemical warfare agents and related toxic substances. Herein data is presented for paraoxon, diisopropylfluorophosphate (DFP), and (CH 3 CH 2 O) 2 P(O)CH 2 SC 6 H 5 (DEPTMP). Solid‐state NMR and IR spectroscopy indicate that all OR and F groups dissociate; this leaves bound PO 4 , F, and OR groups for paraoxon, DFP, and DEPTMP, respectively. For paraoxon, it was shown that one monolayer reacts. For DEPTMP, the OR groups dissociate, but not the PCH 2 SC 6 H 5 group. The nanocrystalline MgO reacts much faster and in higher capacity than typical activated carbon samples, which physisorb but do not destructively adsorb these phosphorous compounds.