Size- and support-dependency in the catalysis of gold

Although homogeneous gold catalysis was known previously, an exponential growth was only induced 12 years ago. The key findings which induce that rise of the field are discussed. This includes early reactions of allenes and furanynes and intermediates of these conversions as well as hydroarylation reactions. Other substrate types addressed are alkynyl epoxides and N-propargyl carboxamides. Important vinylgold intermediates, the transmetalation from gold to other transition metals, the development of new ligands for gold catalysis, and significant contributions from computational chemistry are other crucial points for the field highlighted here.

Gold-Catalyzed Organic Reactions

Metal species with different size (single atoms, nanoclusters, and nanoparticles) show different catalytic behavior for various heterogeneous catalytic reactions. It has been shown in the literature that many factors including the particle size, shape, chemical composition, metal–support interaction, and metal–reactant/solvent interaction can have significant influences on the catalytic properties of metal catalysts. The recent developments of well-controlled synthesis methodologies and advanced characterization tools allow one to correlate the relationships at the molecular level. In this Review, the electronic and geometric structures of single atoms, nanoclusters, and nanoparticles will be discussed. Furthermore, we will summarize the catalytic applications of single atoms, nanoclusters, and nanoparticles for different types of reactions, including CO oxidation, selective oxidation, selective hydrogenation, organic reactions, electrocatalytic, and photocatalytic reactions. We will compare the results o...

Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles.

This critical review is intended to attract the interest of organic chemists and researchers on green and sustainable chemistry on the catalytic activity of supported gold nanoparticles in organic transformations. In the general part of this critical review, emphasis is given to the different procedures to form supported gold nanoparticles and to the importance of the support cooperating in the catalysis. Also the convergence of homogeneous and heterogeneous catalysis in the study of gold nanoparticles has been discussed. The core part of this review is constituted by sections in which the reactions catalyzed by supported gold nanoparticles are described. Special emphasis is made on the unique ability of gold catalysts to promote additions to multiple C–C bonds, benzannulations and alcohol oxidation by oxygen (282 references).

Supported gold nanoparticles as catalysts for organic reactions

Recent advances in transition metal catalyzed oxidation of organic substrates with molecular oxygen.

Selective Vapor-Phase Epoxidation of Propylene over Au/TiO2Catalysts in the Presence of Oxygen and Hydrogen

Vapor-Phase Selective Oxidation of Aliphatic Hydrocarbons over Gold Deposited on Mesoporous Titanium Silicates in the Co-Presence of Oxygen and Hydrogen

An alcohol or a ketone or a mixture thereof is produced from a saturated hydrocarbon or an epoxide is produced from an unsaturated hydrocarbon by passing a mixture comprising of molecular hydrogen, the saturated or unsaturated hydrocarbon and oxygen through a bed of a catalyst comprising a titanium dioxide carrier and ultrafine gold particles deposited on the carrier, thereby effecting the oxidation of the hydrocarbon with oxygen.

Method for production of alcohol, ketone, and aldehyde by oxidation of hydrocarbon

Gas phase selective oxidation of propylene to propylene oxide (PO) or propionaldehyde (PA) in the presence of H2 and O2has been carried out with a propylene conversion in the range of 0.5-3.7% over gold deposited on titanosilicates by deposition-precipitation (DP) method; PO was obtained with a selectivity above 90% at the temperature range of 50 °C-120 °C whereas PA was obtained at temperatures higher than 200 °C with a selectivity above 70% over throughly washed catalysts with low Au loadings.

Selective oxidation of propylene to propylene oxide or propionaldehyde over au supported on titanosilicates in the presence of h2 and o2

A catalyst for partial oxidation of hydrocarbons, comprising gold, titanium oxide and a support having a specific surface area of at least 50 m2/g. The support is preferably silicon oxide and/or aluminum oxide. The gold content of the catalyst is preferred to range from 0.05 to 5 % by weight. Another catalyst for partial oxidation of hydrocarbons comprises gold, a titanium-containing metallic oxide and at least one member selected from the group consisting of alkali metals, alkaline earth metals and thallium. The catalysts thus provided have excellent activity and selectivity in the partial oxidation of hydrocarbons conducted in the presence of hydrogen and oxygen. Also, there is provided a method comprising partially oxidizing hydrocarbons with the use of either of the above catalysts in the presence of hydrogen and oxygen. This method enables production of epoxides from olefinic hydrocarbons and alcohols and A/or ketones from saturated hydrocarbons in high selectivity and high conversion.

Toshio Hayashi

Papers

Selective Vapor-Phase Epoxidation of Propylene over Au/TiO2Catalysts in the Presence of Oxygen and Hydrogen

Vapor-Phase Selective Oxidation of Aliphatic Hydrocarbons over Gold Deposited on Mesoporous Titanium Silicates in the Co-Presence of Oxygen and Hydrogen

Method for production of alcohol, ketone, and aldehyde by oxidation of hydrocarbon

Selective oxidation of propylene to propylene oxide or propionaldehyde over au supported on titanosilicates in the presence of h2 and o2

Catalysts for partial oxidation of hydrocarbons and method of partial oxidation of hydrocarbons