Hydrogenolysis multiplet

The first mechanism proposed for the newly discovered hydrogenolysis of cyclopentane was the doublet mechanism (104), in line with the general multiplet theory of Balandin (105). According to this mechanism, cyclopentane is physically adsorbed on two metal atoms, and stands perpendicular to the surface in the vicinity of physically adsorbed hydrogen atoms (Fig. la). This mechanism, however, does not explain why cyclopentanes are hydro-genolyzed on platinum while cyclohexanes and paraffins are not. 

The experiment points out that Table XV, viz., its upper line, correctly shows the sequence of the ease of hydrogenolysis. It is important evidence in favor of the validity of the multiplet theory. As the molecule is oriented toward the catalyst by the breaking of the bonds. Table XV also shows the orientation of molecules at various temperatures. 

The multiplet theory substantiation of the sequence of hydrogenolysis reactions (Table XV) has been proved to be correct by numerous experimental data, as is seen from Table XVI which gives the results of calculations made similarly to the example with chloronitrobenzene (see above). In Table XVI are listed the classes of compounds subjected to hydrogenolysis [the data from the book by Sabatier (2)], and one compound from each class as an example A indicates theoretically expected products and B, reaction products obtained. The coincidence... 

Metal catalysed reactions are differentiated introducing the concept of facile and demanding reactions. In principle a single atom should be adequate for a facile (structure insensitive) reaction, while an ensemble of surface atoms is required to form a catalytic site adequate for demanding (structure sensitive) reactions. Consequently, there are reactions, which requires more than one species to form multiplets " or ensembles. In other words, some reactions depend on the surface geometry e.g. hydrogenolysis of hydrocarbons), while other may not e.g. hydrogenation of olefinic double bond). 

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