Heterogeneous catalysis organometallic cluster models

The high catalytic activity of zeolites arises from the Bronsted acidity of A1 sites, represented in resonance pair 26.18 the Si Al ratio affects the number of such sites and acid strength of the zeolite. 

Zeolite catalysts are important in the catalytic cracking of heavy petroleum distillates. Their high selectivities and high rates of reactions, coupled with reduced coking effects, are major advantages over the activities of the alumina/silica 

One of the driving forces behind organometallic cluster research is to model metal-surface catalysed processes such as the Fischer-Tropsch reaction. The cluster-surface analogy assumes that discrete organometallic clusters containing rf-block metal atoms are realistic models for the bulk metal. In many small clusters, the arrangements of the metal atoms mimic units from close-packed arrays, e.g. 

The success of modelling studies has been limited, but a well-established and much-cited result is that shown 

Model studies involve transformations of organic fragments which are proposed as surface intermediates, but do 

Recent advances have shown zeolites are effective in catalysing the direct conversion of synthesis gas to motor fuels. The MTO (methanol-to-olefins) process converts MeOH to C2-C4 alkenes and is also catalysed by ZSM-5. The development of a gallium-modified ZSM-5 catalyst (Ga-ZSM-5) has provided an efficient catalyst for the production of aromatic compounds from mixtures of C3 and C4 alkanes (commonly labelled LPG). 

What are the similarities and differences between the structures of a feldspar mineral and a zeolite  

How does a zeolite function as a Lewis acid catalyst  

The following terms have been used in this chapter. 

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Chapter 26 Heterogeneous catalysis organometallic cluster models 807... 

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