title: Efficient hydrolysis of 4-nitrophenylphosphate catalyzed by copper bipyridyl in microemulsions.
abstract: The hydrolysis of 4-nitrophenylphosphate (NPP) in the presence of copper bipyridyl [Cu(bpy)(H(2)O)(2)](2+) in oil in water microemulsion media was investigated. The reaction was monitored by measuring the absorbance of the nitrophenolate ion produced in the reaction aliquots with time. The order of effectiveness of the microemulsion system towards the hydrolysis of NPP in the presence of the copper dipyridyl complex was found to be cationic>anionic>aqueous at neutral pH. The result of the present investigation exhibits catalytic turnovers for metal to NPP ratio of 1:20. Catalysis in the microemulsion mediated reaction solutions was evident even in low concentrations of the metal ions in 1:2000 metal to NPP ratio. An explanation for the enhanced catalytic activity of the [Cu(bpy)(H(2)O)(2)](2+) complex for the hydrolysis of NPP is afforded. The application of the above systems for possible environmental decontamination of aryl organophosphates is anticipated.
authors.affiliation: Department of Chemistry, University of South Africa, P.O. Box 392, UNISA Pretoria, Republic of South Africa.
authors.forename: Fikru
authors.initials: F
authors.lastname: Tafesse
authors.forename: Kennedy
authors.initials: K
authors.lastname: Eguzozie
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry; D006868:Hydrolysis; D007202:Indicators and Reagents / Q000737:chemistry*; D009596:Nitrophenols / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000737:chemistry*
chemical_list: D004655:Emulsions; D007202:Indicators and Reagents; D009596:Nitrophenols; D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; C008644:nitrophenylphosphate; D015082:2,2'-Dipyridyl; D003300:Copper