摘要:

Information concerning the oxidation ofo-xylene and naphthalene, the two main processes for producing phthalic anhydride, is updated and analyzed. New techniques for the preparation of catalysts, all based in the impregnation method and involving the control of parameters such as pH and ionic strength of solutions, are described; the performance of the resulting catalysts is compared with that of catalysts prepared by other methods. Sulfur-containing substances and promoters such as Ag, P, Nb, and Sb have been shown to enhance catalyst performance; studies of their effect on the surface area, acidic properties, and stabilization of the oxidation state of vanadium in supported V2O5catalysts are described.

ISSN:0161-4940    

DOI:10.1080/01614949709353776

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The review presents a comparison and discussion of the substantial amount of information about the state and coordination of titanium ions in titanium silicalites. The results from structural characterization of titanium silicalites with spectral, electrochemical, and quantum-chemical methods with emphasis on location of the Ti ions in framework or extraframework positions, their coordination, and the relationship of some spectral features to concrete structures at the atomic level are summarized. The main methods for the determination of some specific characteristics of titanium silicalite samples are considered—presence of metal ion impurities, extraframework titania, acidity, hydrophobicity, diffusion, and other sterical restrictions. Speculations on how these properties influence the catalytic activities and selectivities of the samples are discussed. Some experimental results for interaction of molecules—solvents, water, and hydrogen peroxide—with titanium silicalites are also presented. The review could be used as an appropriate basis for continuation of the discussion on molecular aspects of catalytic activity of titanium silicalites in partial oxidation with hydrogen peroxide.

ISSN:0161-4940    

DOI:10.1080/01614949709353777

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Hardening of vegetable oils is reviewed from an engineering point of view. The present review focuses on kinetics of the hydrogenation and relevant transport and adsorption steps. It aims to contribute to accelerate new research to improve substantially on selectivities in general and a decrease of trans fatty acid content in particular.

ISSN:0161-4940    

DOI:10.1080/01614949709353778

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor