An-Najah Staff

Supported tetra(-4-pyridyl)porphyrinato-manganese(III) [MnIII(TPyP)]+ and -tin(IV) [SnIV(TPyP)]2+ have been prepared. The solid support was iodonated poly(siloxane) surface prepared by condensation reactions of (EtO)4Si with (MeO)3Si(CH2)3I. The supported metalloporphyrins were employed as catalysts for the oxidation reactions of 1-octene and of cyclohexene. NaBH4 was used to reduce [MnIII(TPyP)]+ and [SnIV(TPyP)]2+ back to their catalytically active MnII and SnII forms, respectively. Contrary to their homogeneous counterparts, both of the supported metalloporphyrins catalysed the cyclohexene oxidation reaction to yield only 2-cyclohexen-1-one with no other products over a reaction time of 10 h. In addition to cyclohexene oxidation, the supported [MnIII(TPyP)]+ catalysed 1-octene oxidation as well, whereas the supported [SnIV(TPyP)]2+ was inactive for the oxidation of 1-octene.

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Water-in-oil (w/o) microemulsions are very appealing reaction media due to their ability to provide huge surface of contact between water-soluble and oil-soluble reactants. Their application as reaction media, including the preparation of nanoparticles, is, however, limited to water soluble precursors. In this study, we present a first step scheme in a two-step process for the preparation of metal oxide nanoparticles starting from their water-insoluble metal oxide bulk powder. This step involves solubilizing the metal oxide in the water pools of the microemulsion with the aid of a solubilizing agent. The variables affecting the solubilizing capacity of iron and copper oxides,as examples of important metal oxides, in single HCl-containing AOT/water/isooctane microemulsions were investigated. The effect of the following variables on the solubilization capacity is reported, namely, mixing time, surfactant concentration, water to surfactant mole ratio (R),and the nominal concentration of HCl in the water pool. At 300-rpm, time-invariant concentration of the metals in the microemulsions was achieved in about 6 hours. These values were quoted as the solubilization capacity of the metal oxide at the corresponding conditions.Solubilization capacity increased linearly with the surfactant concentration and R, and portrait a power function with the nominal concentration of HCl in the water pool. A mathematical model previously derived to describe nanoparticle uptake by single microemulsion accurately accounted for the effect of the aforementioned variables on the solubilization capacity.