다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

1.0. Introduction 4044 2.0. Biomass Chemistry and Growth Rates 4047 2.1. Lignocellulose and Starch-Based Plants 4047 2.2. Triglyceride-Producing Plants 4049 2.3. Algae 4050 2.4. Terpenes and Rubber-Producing Plants 4052 3.0. Biomass Gasification 4052 3.1. Gasification Chemistry 4052 3.2. Gasification Reactors 4054 3.3. Supercritical Gasification 4054 3.4. Solar Gasification 4055 3.5. Gas Conditioning 4055 4.0. Syn-Gas Utilization 4056 4.1. Hydrogen Production by Water−Gas Shift Reaction 4056

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Synthesis of transportation fuels from biomass: chemistry, catalysts, and engineering.

4.3. Reaction Mechanism 2373 4.4. Asymmetric Synthesis 2374 4.5. Outlook 2374 5. Alternating Polymerization of Oxiranes and CO2 2374 5.1. Reaction Outlines 2374 5.2. Catalyst 2376 5.3. Asymmetric Polymerization 2377 5.4. Immobilized Catalysts 2377 6. Synthesis of Urea and Urethane Derivatives 2378 7. Synthesis of Carboxylic Acid 2379 8. Synthesis of Esters and Lactones 2380 9. Synthesis of Isocyanates 2382 10. Hydrogenation and Hydroformylation, and Alcohol Homologation 2382

Transformation of carbon dioxide.

Interest in catalysis by metal nanoparticles (NPs) is increasing dramatically, as reflected by the large number of publications in the last five years. This field, "semi-heterogeneous catalysis", is at the frontier between homogeneous and heterogeneous catalysis, and progress has been made in the efficiency and selectivity of reactions and recovery and recyclability of the catalytic materials. Usually NP catalysts are prepared from a metal salt, a reducing agent, and a stabilizer and are supported on an oxide, charcoal, or a zeolite. Besides the polymers and oxides that used to be employed as standard, innovative stabilizers, media, and supports have appeared, such as dendrimers, specific ligands, ionic liquids, surfactants, membranes, carbon nanotubes, and a variety of oxides. Ligand-free procedures have provided remarkable results with extremely low metal loading. The Review presents the recent developments and the use of NP catalysis in organic synthesis, for example, in hydrogenation and C--C coupling reactions, and the heterogeneous oxidation of CO on gold NPs.

Nanoparticles as Recyclable Catalysts: The Frontier between Homogeneous and Heterogeneous Catalysis

Owing to the increasing emissions of carbon dioxide (CO2), human life and the ecological environment have been affected by global warming and climate changes. To mitigate the concentration of CO2 in the atmosphere various strategies have been implemented such as separation, storage, and utilization of CO2. Although it has been explored for many years, hydrogenation reaction, an important representative among chemical conversions of CO2, offers challenging opportunities for sustainable development in energy and the environment. Indeed, the hydrogenation of CO2 not only reduces the increasing CO2 buildup but also produces fuels and chemicals. In this critical review we discuss recent developments in this area, with emphases on catalytic reactivity, reactor innovation, and reaction mechanism. We also provide an overview regarding the challenges and opportunities for future research in the field (319 references).

Recent advances in catalytic hydrogenation of carbon dioxide

This paper gives a comprehensive report on a two-step synthesis of dimethyl carbonate (DMC) from epoxides, carbon dioxide and methanol using various basic metal oxide catalysts. The first step is the reaction of ethylene oxide or propylene oxide with CO 2 to form the corresponding cyclic carbonates, and the second step is the transesterification reaction of the cyclic carbonates with methanol to DMC and glycols. Among the catalysts examined, MgO is the most active and selective for both these reactions. Other alcohols can be used for the second step, but the activity decreases as the carbon number of the alcohol increases. Although a one-pot synthesis of DMC, i.e. the sequential reaction of the epoxide, CO 2 and methanol, is also possible with MgO, the selectivity is low because of the alcoholysis of the epoxide. In contrast with the reactions of ethylene oxide and propylene oxide, when styrene oxide is used for the first reaction and for the one-pot synthesis, mandelic acid is produced. Basic properties of the metal oxide catalysts were measured by temperature programmed desorption of CO 2 . The relationship between the catalytic performance and the basic property is discussed.

Synthesis of dimethyl carbonate and glycols from carbon dioxide, epoxides, and methanol using heterogeneous basic metal oxide catalysts with high activity and selectivity

Development in the green synthesis of cyclic carbonate from carbon dioxide using ionic liquids

Synthesis of styrene carbonate from styrene oxide and carbon dioxide in the presence of zinc bromide and ionic liquid under mild conditions

Various nitrogen-doped carbon materials were prepared via treatments of an activated carbon (AC) with ammonia and hydrogen peroxide, and their catalytic performance was tested for aerobic oxidation of several alcohols in ethanol. The amount and nature of doped nitrogen-species were examined by X-ray photoelectron spectroscopy to discuss the genesis of active species by nitrogen doping. The nitrogen-doped AC catalysts are active for the oxidation of such alcohols as benzyl alcohol, cinnamyl alcohol, and 5-(hydroxymethyl)-2-furaldehyde, and in some cases, they are even more selective to the oxidation of the hydroxyl group compared with conventional Pt/C and Ru/C catalysts, for which coupling products with the ethanol solvent are formed at low conversion levels. Graphite-type doped nitrogen species are significant for the formation of active sites on the surface of AC. The present results demonstrate the potential of nitrogen-doped AC materials as metal-free, carbon-based catalysts useable for organic synthe...

Nitrogen-Doped, Metal-Free Activated Carbon Catalysts for Aerobic Oxidation of Alcohols

Supported Pd catalysts exhibit poor selectivity for the steam reforming of methanol, CH 3 OH+H 2 O→3H 2 +CO 2 ; hydrogen and carbon monoxide are predominantly produced by decomposition of methanol, CH 3 OH→2H 2 +CO. Upon addition of Zn to the supported Pd catalysts, however, the selectivity for the steam reforming is markedly improved. In particular, over Zn-modified Pd catalysts supported on CeO 2 and active carbon (AC), the selectivity attained is 99%. The rates of hydrogen formation of Zn-modified Pd/CeO 2 and Pd/AC are also enhanced compared with those of Zn-free ones. The selectivity for the steam reforming of Pd/CeO 2 is also improved upon the addition of such metals as Cd, In and Ga as well as Zn. These catalytic features may be ascribed to the alloying of Pd with Zn, Cd, In and Ga by the reduction of these modified Pd/CeO 2 catalysts. The effect of preparation conditions on the Zn-modified Pd/CeO 2 is also investigated. Pd/Zn/CeO 2 catalysts prepared by co-precipitation method are more highly active and selective than those prepared by impregnation or deposition–precipitation method. The rate of hydrogen formation of Zn-modified Pd/CeO 2 catalyst with Pd/Zn ratio of 1/1.5 prepared by co-precipitation method is highest among the Zn-modified Pd/CeO 2 catalysts examined. The Zn-modified Pd/CeO 2 catalyst has good thermal stability as well as high activity and selectivity and no deactivation occurred when the reaction was conducted at 623 K, the temperature at which Cu/ZnO catalyst lost its activity.

Masahiko Arai

Papers

Synthesis of dimethyl carbonate and glycols from carbon dioxide, epoxides, and methanol using heterogeneous basic metal oxide catalysts with high activity and selectivity

Development in the green synthesis of cyclic carbonate from carbon dioxide using ionic liquids

Synthesis of styrene carbonate from styrene oxide and carbon dioxide in the presence of zinc bromide and ionic liquid under mild conditions

Nitrogen-Doped, Metal-Free Activated Carbon Catalysts for Aerobic Oxidation of Alcohols

Effect of Zn addition to supported Pd catalysts in the steam reforming of methanol