II. Structure of Perovskites 1982 A. Crystal Structure 1982 B. Nonstoichiometry in Perovskites 1983 1. Oxygen Nonstoichiometry 1983 2. Cation Nonstoichiometry 1984 C. Physical Properties 1985 D. Adsorption Properties 1986 1. CO and NO Adsorption 1986 2. Oxygen Adsorption 1987 E. Specific Surface and Porosity 1987 F. Thermal Stability in a Reducing Atmosphere 1989 III. Acid−Base and Redox Properties 1990 A. Acidity and Basicity 1990 B. Redox Processes 1991 1. Kinetics and Mechanisms 1992 2. Reduction−Oxidation Cycles 1993 C. Ion Mobility 1993 1. Oxygen Transport 1993 2. Cation Transport 1994 IV. Heterogeneous Catalysis 1995 A. Oxidation Reactions 1995 1. CO Oxidation 1995 2. Oxidation of Hydrocarbons 1996 B. Pollution Abatement 2001 1. NOx Decomposition 2001 2. Exhaust Treatment 2002 3. Stability 2004 C. Hydrogenation and Hydrogenolysis Reactions 2004 1. Hydrogenation of Carbon Oxides 2004 2. Hydrogenation and Hydrogenolysis Reactions 2006

Chemical structures and performance of perovskite oxides.

Palladium-catalyzed carbonylation reactions of aromatic halides in the presence of various nucleophiles have undergone rapid development since the pioneering work of Heck and co-workers in 1974, such that nowadays a plethora of palladium catalysts are available for different carbonylative transformations. The carboxylic acid derivatives, aldehydes, and ketones prepared in this way are important intermediates in the manufacture of dyes, pharmaceuticals, agrochemicals, and other industrial products. In this Review, the recent academic developments in this area and the first industrial processes are summarized.

Palladium-catalyzed carbonylation reactions of aryl halides and related compounds.

A variety of spray pyrolysis (SP) techniques have been developed to directly produce ceramic powders from solutions. This paper reviews the current status of these processes in terms of the process parameters that enable the formation of particles with controlled morphology and composition. A model incorporating solute diffusion in the droplet and solvent evaporation from the droplet surface is presented to establish the critical parameters leading to solid particle formation. The model illustrates that solid particles can be obtained if solutes with high solubility and a large difference between the critical supersaturation and equilibrium concentration are used and if the process is designed to avoid solvent boiling. It is demonstrated that mixed metal oxide, non-oxide, and composite particles that are solid, hollow, porous, or fibrous can be produced by modifying the precursor characteristics, solution properties, and process parameters. The physical and chemical flexibility of SP processes offers numerous opportunities for the controlled synthesis of advanced ceramic powders and films. However, production rates are limited by the need to produce <5-[mu]m-diameter droplets and to avoid subsequent droplet coagulation. Developments in process controls, atomization, and system design are required for wider commercialization of SP-type processes.

Ceramic Powder Synthesis by Spray Pyrolysis

Mixed ionic-electronic conducting (MIEC) ceramic-based membranes for oxygen separation

Fourier transform IR spectroscopy has been used to investigate the interaction of carbon dioxide with polymers. IR transmission and attenuated total reflectance spectra were obtained for CO2 impregnated into polymer films. It has been shown that the polymers possessing electron-donating functional groups (e.g., carbonyl groups) exhibit specific interactions with CO2, most probably of Lewis acid−base nature. An unusual aspect is the use of the bending mode (ν2) of CO2 to probe polymer−CO2 interactions. The evidence of the interaction is the observation of the splitting of the band corresponding to the CO2 ν2 mode. This splitting indicates that the double degeneracy of the ν2 mode is removed due to the interaction of electron lone pairs of the carbonyl oxygen with the carbon atom of the CO2 molecule. This splitting has not been observed for polymers lacking electron-donating functional groups (e.g., poly(ethylene)). In contrast, the ν3 mode shows little if any sensitivity to this interaction, which is in ac...

Specific Intermolecular Interaction of Carbon Dioxide with Polymers

The partial oxidation of methane to synthesis gas (syngas, CO + H2) was performed in a mixed-conducting perovskite dense membrane reactor at 850°C, in which oxygen was separated from air and simultaneously fed into the methane stream. Steady-state oxygen permeation rates for La1-xA′xFe0.8 Co0.2O3-δ perovskite membranes in nonreacting air/helium experiments were in the order of A′x = Ba0.8 > Ba0.6 > Ca0.6 > Sr0.6. Deep oxidation products were obtained from a La0.2 Ba0.8 Fe0.8 Co0.2 O3–δ disk-shaped membrane reactor without catalyst, with a 4.6% CH4 inlet stream. These products were further reformed to syngas when a downstream catalytic bed was added. Packing the 5% Ni/Al2O3 catalyst directly on the membrane reaction-side surface resulted in a slow fivefold increase in O2 permeation, and a fourfold increase in CH4 conversion. XRD, EDS, and SEM analyses revealed structure and composition changes on the membrane surfaces. Oxygen continuously transported from the air side appeared to stabilize the membrane interior, and the reactor was operated for up to 850 h.

Dense perovskite membrane reactors for partial oxidation of methane to syngas

La1-xA′xFe0.8Co0.2O3-δ (A′= Ca, Sr, Ba) perovskite powders were synthesized to attain the desired properties of high O2 flux and stability under reducing conditions. Steady-state oxygen permeation rates for La1-xA′xFe0.8-Co0.2O3-δ perovskite membranes in nonreacting experiments with air on one side and helium on the other side of the membrane were in the order A′x= Ba0.8 > Ba0.6 > Ca0.6 > Sr0.6. Partial oxidation of methane to syngas (CO + H2) was performed in a dense La0.2Ba0.8Fe0.8Co0.2O3-δ membrane reactor at 850°C in which oxygen was separated from air and simultaneously fed into the methane stream. The reducing atmosphere affected the membrane reaction-side surface while barium enrichment occurred on the air-side surface. Oxygen continuously transported from the air side appeared to stabilize the membrane interior, and the reactor was operated for up to 850 h.

Dense Perovskite, La1-xA′xFe1-yCoyO3-δ (A′= Ba, Sr, Ca), Membrane Synthesis, Applications, and Characterization

The mechanism of phosphine-modified rhodium-catalyzed hydroformylation studied by CIR-FTIR

Mechanistic studies of the palladium-catalyzed reaction of methanol with bromobenzene and carbon monoxide to produce methyl benzoate. 1. Stoichiometric study

A process for the preparation of nanophase solid state materials having crystallite morphology and particle sizes in the range of from about 1 nm to 30 nm is disclosed. Novel nanophase solid state materials are also disclosed.

William R. Moser

Papers

Dense perovskite membrane reactors for partial oxidation of methane to syngas

Dense Perovskite, La1-xA′xFe1-yCoyO3-δ (A′= Ba, Sr, Ca), Membrane Synthesis, Applications, and Characterization

The mechanism of phosphine-modified rhodium-catalyzed hydroformylation studied by CIR-FTIR

Mechanistic studies of the palladium-catalyzed reaction of methanol with bromobenzene and carbon monoxide to produce methyl benzoate. 1. Stoichiometric study

Preparation of nanophase solid state materials.