摘要:

Several authors have correlated catalyst structure to catalytic behavior in selective oxidation reactions. Sleight [1] reviewed the importance of the scheelite structure for the allylic oxidation and ammonoxidation of olefins; Grasselli and co-workers [2–4] extensively examined the relationship between structure and catalytic activity of bismuth-molybdates, uranium-antirnonates, and bismuth-cerium molybdates. Bordes and Courtine [5] correlated the activity in mild oxidation of 1-butene to the properties of the structure of vanadium-phosphorus oxides. However, little attention has been given in the literature to the role of the rutile structure in allylic oxidation reactions even though the high activity and selectivity of antimony oxides stabilized in matrices with rutile structure (SnO2and FeSbO4) in olefins oxidation and ammonoxidation have been known for several years. Furthermore, Tables 1 and 2 indicate that the kinetic and catalytic behavior of antimony-based catalysts in allylic oxidation reactions are very different from that of molybdate-based catalysts. This suggests that antimony- and molybdate-based catalysts are two distinct classes of catalysts of allylic oxidation, in agreement with a recent suggestion by Grasselli et al. [13].

ISSN:0161-4940    

DOI:10.1080/01614948608082250

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

In the 26 years since the term “shape-selective catalysis” was coined by P. B. Weisz and V. J. Frilette [1] to describe the unique catalytic properties of small pore molecular sieve zeolites, great strides in the use of shape-selective zeolites have been made, both scientifically and technologically. Since then, in addition to small pore zeolites, synthetic medium pore zeolites, such as ZSM-5 [2], ZSM-11 [3], ZSM-22 [4], ZSM-23 [5], ZSM-35 [6], ZSM-38 [7], ZSM-48 [8], etc., have been discovered. The availability of these synthetic medium pore zeolites has expanded the realm of “shape selectivity” beyond the original discovery of selective conversion of straight chain molecules to include certain branched molecules, single-ring aromatics, naphthenes, and nonhydrocarbons with a critical molecular dimension smaller than about 6 Å.

ISSN:0161-4940    

DOI:10.1080/01614948608082251

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A more complete understanding of the structural and mechanistic details of a catalyzed heterogeneous reaction leads both directly and indirectly to the development of new and better catalysts. For catalyst technology, the most sensitive probe of catalysts performance will continue to be the rate and selectivity of a chemical reaction. However, these macroscopic observations, adequate for determining how good a catalyst is, require supplementary microscopic information to remove ambiguity in the deduction of a catalytic mechanism. This information, almost down to the atomic level, concerning the structure and reactivity of the intermediates, the nature of adsorption sites (and sometimes the active sites) and their number, is the main objective of the science of catalysis. The most promising approach to this problem is the use of suitable probe molecules for the quantitative titration of site density and qualitative characterization of their nature by means of surface spectroscopies of the chemisorbed probe molecules [1, 21. This framework of action is schematically represented in Fig.1.

ISSN:0161-4940    

DOI:10.1080/01614948608082252

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

In 1925, H. S. Taylor [1] hypothesized that a heterogeneously catalyzed reaction occurs predominantly at a few distinct places on the catalyst's surface called “active sites.” Many models of the active site have been proposed [1–32] over the years. However, at present there is little agreement about what causes the active sites to have special catalytic properties.

ISSN:0161-4940    

DOI:10.1080/01614948608082253

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0161-4940    

DOI:10.1080/01614948608082249

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor