TY - JOUR
T1 - Catalytic oxidative decomposition of dimethyl methylphosphonate over cu-substituted hydroxyapatite
AU - Lee, Kwan Young
AU - Houalla, Marwan
AU - Hercules, David M.
AU - Hall, W. Keith
PY - 1994/1/1
Y1 - 1994/1/1
N2 - The oxidative decomposition of dimethyl methyiphosphonate (DMMP) has been studied over Cu-substituted hydroxyapatite catalysts in a flow reactor in the temperature range 373-773 K. By substitution of a portion of the Ca2+ by Cu2+ in the hydroxyapatite lattice, the catalytic activity was markedly increased. The composition Cu2Ca8(PO4)6(OH)2, herein called Cu2-HA, had the highest activity among these catalysts. All the catalysts showed 100% conversion at the beginning of the reaction, but became deactivated after a period of time. Only CO2 and H2O were produced during the "protection period" of the 100% conversion. With deactivation, CO2 formation decreased and methanol and dimethyl ether appeared as products. A phosphorus-containing product was not detected in the gas phase. Some condensate of phosphoric acid appeared in the outlet of the reactor after deactivation. Several analytical methods revealed that carbonaceous compounds did not remain on the surface after 773-K oxidative regeneration, but the phosphorus compounds that had accumulated during the reaction were not eliminated. The catalytic activity of Cu-substituted hydroxyapatite was compared to that of conventional supported Pt catalysts. This study suggested that easily made and cheap Cu-substituted hydroxyapatite catalysts could be used as successful alternatives to conventional adsorbents and catalytic systems based on supported noble metals devised for protection against nerve gases in warfare.
AB - The oxidative decomposition of dimethyl methyiphosphonate (DMMP) has been studied over Cu-substituted hydroxyapatite catalysts in a flow reactor in the temperature range 373-773 K. By substitution of a portion of the Ca2+ by Cu2+ in the hydroxyapatite lattice, the catalytic activity was markedly increased. The composition Cu2Ca8(PO4)6(OH)2, herein called Cu2-HA, had the highest activity among these catalysts. All the catalysts showed 100% conversion at the beginning of the reaction, but became deactivated after a period of time. Only CO2 and H2O were produced during the "protection period" of the 100% conversion. With deactivation, CO2 formation decreased and methanol and dimethyl ether appeared as products. A phosphorus-containing product was not detected in the gas phase. Some condensate of phosphoric acid appeared in the outlet of the reactor after deactivation. Several analytical methods revealed that carbonaceous compounds did not remain on the surface after 773-K oxidative regeneration, but the phosphorus compounds that had accumulated during the reaction were not eliminated. The catalytic activity of Cu-substituted hydroxyapatite was compared to that of conventional supported Pt catalysts. This study suggested that easily made and cheap Cu-substituted hydroxyapatite catalysts could be used as successful alternatives to conventional adsorbents and catalytic systems based on supported noble metals devised for protection against nerve gases in warfare.
UR - http://www.scopus.com/inward/record.url?scp=0001682704&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0001682704&partnerID=8YFLogxK
U2 - 10.1006/jcat.1994.1026
DO - 10.1006/jcat.1994.1026
M3 - Article
AN - SCOPUS:0001682704
VL - 145
SP - 223
EP - 231
JO - Journal of Catalysis
JF - Journal of Catalysis
SN - 0021-9517
IS - 1
ER -