Naming Surface Species in Organic Reactions on Surfaces

Avoiding poisons is aided by scrupulous attention to cleanliness. 

Raney catalysts are usually shipped under water, so if water is an undesirable solvent, it must be displaced by appropriate washings with the desired solvent. Care should be taken when using ketones. Special care should be taken with nitrobenzene, which undergoes highly exothermic hydrogenation at room temperature (see Section 2.1.3).53 

DRAWING AND NAMING SURFACE SPECIES IN ORGANIC REACTIONS ON SURFACES 

Without substantial artistic talent, depicting organic reaction mechanisms on surfaces is difficult. Over the years, a variety of methods have been invented and used with differing successes. Frequently used is an asterisk, an M, or sometimes the symbol of the metal catalyst to designate a surface catalytic 

Likewise, showing a generic surface such as a flat plane.54 without emphasizing the individual atoms is awkward, as shown in Fig. 1.8. 

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Drawing and Naming Surface Species in Organic Reactions on Surfaces... 

Zeolites are the main catalyst in the petrochemical industry. The importance of these aluminosilicates is due to their capacity to promote many important reactions. By analogy with superacid media (1), carbocations are believed to be key intermediates in these reactions. However, simple carbocationic species are seldom observed on the zeolite surface as persistent intermediates within the time-scale of spectroscopic techniques. Indeed, only some conjugated cyclic carbocations were observed as long living species, but covalent intermediates, namely alkyl-aluminumsilyl oxonium ions (2) (scheme 1), where the organic moiety is bonded to the zeolite structure, are usually thermodynamically more stable than the free carbocations (3,4). 

In summary, the Kobayashi solution to the development of a SILP for catalytic applications in liquid biphasic conditions implies the adoption of a more robust anchoring technique of the catalytically active species to the solid support and of a IL/solvent pair as far as possible in terms of mutual solubility, namely water and [dbim][SbF6]. The role of the IL impregnated on the solid support is that of creating a hydrophobic environment on the surface of the silica material where the catalyst, ionically bound to the organic spacer, exerts its role promoting the desired reaction. Since the catalyst is easily separated from water, the system could be easily optimised for recycle. 

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