摘要:

This review presents the iron phosphorus oxides used as catalysts for isobutyric acid oxidative dehydrogenation. Research on this catalytic system has been developed in the last decade and many publications have been devoted to this reaction, as it can be a step in a new process of production of methyl methacrylate. We emphasize particularly the nature of the active phase, the active centers, and the role of water and promoters. The mechanistic aspects of the reaction, which corresponds to an extension of the Mars and van Krevelen mechanism with a special role of water partial pressure, are discussed.

ISSN:0161-4940    

DOI:10.1080/01614949808007104

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The fluid catalytic cracking (FCC) process converts heavy oil into voluable fuel products and petrochemical feedstocks. Environmental regulations are a key driving force for reducing FCC process air-pollutant emissions and for changing the composition of fuel products. Environmental considerations are affecting the design and operation of the FCC and are providing opportunities for the development of in-process additives. The present article reviews developments in these environmental technologies.

ISSN:0161-4940    

DOI:10.1080/01614949808007105

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The synthesis of a large number of fine chemicals, particularly in the field of flavor and fragrance chemistry [1,2] and pharmaceuticals [3], involves the selective hydrogenation of unsaturated carbonyl intermediates as a critical step. The hydrogenation of α,β-unsaturated carbonyls into saturated carbonyls is comparatively easy to achieve because thermodynamics favor the hydro-genation of the C═C bonds; therefore, research efforts were more directed at improving the selectivity to unsaturated alcohols. When a substituent is present on the carbon atom of the carbonyl group (i.e. with ketones), there is no chance to hydrogenate selectively the C═O bond, and saturated ketones are obtained with a high yield. This review is thus mostly restricted to the hydrogenation of α, β-unsaturated aldehydes into the corresponding unsaturated alcohols.

ISSN:0161-4940    

DOI:10.1080/01614949808007106

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The application of (picosecond) nonlinear infrared spectroscopy to investigate zeolite catalysts and adsorbates is reviewed. In these time-resolved experiments, one specific vibration in the zeolite system (i.e., a zeolite or adsorbate vibration) is selectively excited with an ultrashort (tunable) mid-infrared pulse. The effect of this excitation and the subsequent energy relaxation can be monitored real time, providing information on the structure of the bare zeolite and adsorption complexes. More importantly, with this technique the picosecond energy flow at the catalytic site and thedynamicsof the catalyst-adsorbate interaction can be investigated: Short-lived transient species (e.g., reaction intermediates) are observed and the picosecond relaxation rates and pathways at the catalytic site render insights into the dynamics of the interaction between the zeolite catalyst and its adsorbates at a molecular level. This illustrates the potential of time-resolved infrared spectroscopy in the investigations of catalytic systems.

ISSN:0161-4940    

DOI:10.1080/01614949808007107

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Heterogeneous catalysis plays a central role in most chemical reactions of industrial importance [1], but new advanced catalysts (superselective, able to transform new feedstocks and to synthesize new products, etc.) are required to comply with the future energy, safety, health, and environmental needs of the chemical industry [2]. The design of these new catalytic materials requires further understanding of the surface processes determining the catalytic transformations [3].

ISSN:0161-4940    

DOI:10.1080/01614949808007108

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0161-4940    

DOI:10.1080/01614949808007109

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor