Catalysis by some metal oxides modified with phosphate ions

Surface acidity of phosphate modified La2O3,CeO2 and SnO2 has been estimated by titrimetric Method using Hammett Indicators.Mixed Oxides of tin and lanthanum have also been prepared and subjected to phosphate modification.Surface characterizartion of the samples has been carried out using XRD, surface area,thermal analysis and IR spectroscopy. Phosphate content in the samples has been chemically estimated. The catalytic activity for benzylation and esterification reaction has also been investigated.

Electron donating properties and catalytic actiVity of cerium oxide and its mixed oxides with alumina

The electron donating properties of Ce02 and its mixed oxides with alumina have been determined from the studies of adsorption of electron acceptors of various electron affinities on the surface of these oxides. The catalytic activity of these oxides towards some reactions such as oxidation of alcohols and reduction of ketones have been Correlated with their surface electrondonor properties. The surface acidity/basicity of these oxides have also been determined by titration method using a set of Hammett indicators.

Basicity and electron donor properties of lanthanum oxide and its mixed oxides with alumina

The electron donating properties of La2O3 activated at 300, 500 and 800·C and its mixed oxides with alumina are reported from the studies on adsorption of electron acceptors of varying electron affinity on La203. The electron acceptors with their electron affinity values given in parenthesis are: 7,7,8,8-tetracyanoquinodimethane (2.84 eV), 2,3,5,6-tetrachloro-I,4-benzoquinone (2.40 eV) and p-dinitrobenzene(l.77eV). The basicity of the oxide has been determined by titration with n-butylamine and Ho.max values are reported. The limit of electron transfer from the oxide to the electron acceptor is between 2.40 and 1.77 eV. It is observed that La203 promotes the surface electron properties of alumina without changing its limit of electron transfer.

Acid-base, electron-donating and magnetic properties of Nd2O3 and its mixed oxides with alumina catalysts

The electron donor properties of Nd2O3 activated at 300, 500 and 800°C were investigated through studies on the adsorption of electron acceptors of various electron affinities - 7, 7, 8,8-tetracyanoquinodimethane (2.84 eV). 2, 3, 5, 6-tetrachloro-l , 4-benzoquinone (2.40 eV). p-dinitrobenzene (1.77 eV), and m-dinitrobenzene (1.26 eV) in solvents acetonitrile and 1, 4-dioxan. The extent of electron transfer during adsorption has been found from magnetic measurements and electronic spectral data. The corresponding data on mixed oxides of neodymium and aluminium are reported for various. compositions. The acid-base properties of catalysts were also determined using a set of Hammett indicators.

Surface acidity/basicity of yttria and its mixed oxides with alumina catalysts

Acid/base strength distribution of Y2O3 and its mixed oxides with alumina catalysts are measured on Hammett acidity function scale and expressed in terms of H0max value. Basicity of Y2O3 increases with increase in activation temperature and for mixed oxides the basicity increases with increase in concentration of Y2O3, in the catalyst.

Electron Donating Property and Catalytic Activity of Perovskite-type Mixed Oxides (ABO3 ) Consisting of Rare Earth and 3d Transition Metals

The catalytic activity of Perovskite-type mixed oxides (LaCo03 . PrCo03 and SmCo03 ) for the reduction of cyclohexanone to cyclohexanol with 2-propanol (Meerwein-Ponndorf-Verley reduction) has been studied. The data have been correlated with the surface electron donor properties of these mixed oxides.

Electron donor strength of rare earth oxides

The adsorption of electron acceptors, viz.,7,7,8,8-tetracyanoquinodimethane(TCNQ), 2,3,5,6-tetrachloro-p- benzoquinone (chloranil) and p-dinitrobenzene (PDNB) on the surface of three rare earth oxides Y2O3, Nd203 and Pr6O11 has been studied in acetonitrile and dioxan. From the radical concentration on the surface determined using ESR spectral data, the electron donor strength of the rare earth oxides are reported.

Acid-Base, Surface electron donating and catalytic properties of binary oxides of Zr with rare earth elements

Department of Applied Chemistry, Cochin University of Science and Technology

Surface Electron Donor Properties of Dy2O3,Y2O3 and Their Mixed Oxides with Alumina Catalyst

The limit of electron transfer in electron affinity from the oxide surface to the electron acceptor (EA) are reported from the adsorption of EA on DY203, mixed oxides of DY203 with alumina and mixed oxides of Y203 with y-alumina. The extent of electron transfer is understood from magnetic measurements.

Catalytic activity of some of the perovskite-type mixed oxides (ABO3) consisting of rare earth and 3d transition metals

The catalytic activity of some of the ABO3 (A = La, Pr and Sm, B= Cr, Mn, Fe, Co and Ni) perovskite-type oxides for the liquid phase reduction of ketone and oxidation of alcohol in 2-propanol medium has been studied. The data have been correlated with the surface electron donor properties of these oxides. The surface electron donor properties have been determined from the adsorption of electron acceptors of varying electron affinities on the oxide surface.

The surface acidity/basicity and catalytic activity of ternary oxides of La, Ce and AI

The surface acidity and basicity of ternary oxides of La, Ce and AI have been determined using a set of Hammett indicators. The data have been correlated with the catalytic activity of these oxides towards the liquid phase reduction of cycIohexanone in 2-propanol.

Surface acidity/basicity and catalytic activity of ternary oxides of Al, Ce and Dy

The surface acidity and basicity of ternary oxides of AI, Ce and Dy have been determined using a set of Hammett indicators. The data have been correlated with the catalytic activity of these oxides towards the liquid phase reduction of cyclohexanone in 2-propanol. The reaction is favoured by the higher basicity of the ternary oxide.

Surface acidity/basicity and catalytic activity of mixed oxides of Zr, La and Al

The surface acidity/basicity of binary oxides of Zr and La and the ternary oxides of Zr, La and Al are reported. The data have been correlated with their catalytic activity towards liquid phase reduction of cyclohexanone.

Acidity, basicity and catalytic activity of La−Zn mixed oxides

Surface acidity/Basicity of mixed oxides of La and Zn activated at three different temperatures were determined. The data have been correlated with the catalytic activity for liquid phase reduction of cyclohexanone in isopropanol.

Preparation and Characterization of Magnetic and Non-magnetic Nanosized Spinel Oxides, Nickel Nanoparticles and Nickel-Polymer Nanocomposites

Department of Physics, Cochin University of Science and Technology