Multiplet theory of catalysis

Here the role of the geometrical factors in chemisorption is especially vividly expressed. These factors have been analyzed in detail by A. A. Balandin and co-workers in their papers (see, for example, ref. 18) on the multiplet theory of catalysis, in which they show their prime importance in a number of cases of the catalytic process. The electronic mechanism of chemisorption does not at all exclude these factors, but just stresses their role it retains the geometrical schemes of the multiplet theory but gives them physical content. 

The Nature of Reactants. No less effect on z and e is exerted by the nature of the reacting atoms of the molecule. The values of z and e are distinctly different for hydrocarbons, amines, and alcohols (on the same or similar catalysts). This complies with the multiplet theory of catalysis, according to which in the three reactions the following atomic groups, in which the vertical bonds pass over to the horizontal, are in contact with the catalyst ... 

A. A. Balandin, Multiplet Theory of Catalysis Theory of Hydrogenation, Moscow State Univ., Moscow, 1970, in Russian. 

A.A. Balandin. Multipletnaya teoriya kataliza (The Multiplet Theory of Catalysis), pt. 3, MGU Publ., 1970. 

The following facts convince one that Eqs. (II.9)-(II.12) correspond to relations existing in reality, which confirms the multiplet theory of catalysis. 

Balandin not only developed the multiplet theory of catalysis but was its most active proponent. He constantly wrote papers stating the achievements in this field. Recentl3q ho wrote the monograph The Multiplet Theory of Catalysis, two parts of which were published by... 

Scheme 4.10. corresponds to the "doublet" scheme of the multiplet theory of catalysis by Balandin but the Ni centers should not be applied as centers of the multiplet theory but used in accordance with the principle of microscopic reversibility . ... 

Balandin, A.A. (1970) Multiplet theory of catalysis. Part III. Theory of hydrogenation. Classification of organic reactions. Theory of complicate reactions. Structural algebra in chemistry, (russ., Klabimovskii, E.I., ed.), Publ. Moscow University, 475 pp. 

Balandin A. 1969. Modem state of the multiplet theory of heterogeneous catalysis. Adv Catal 19 1. 

The practice of considering the catalyst as a featureless surface or a planar array of atomic centers deprives theory of an adequate concern for the geometry of the transition from reactants to products. Balandin (23) recognized the importance of the concept of a transition state to the development of a mechanistic theory of catalysis, and in his hands the multiplet theory proved fruitful. However the directional properties of binding orbitals, a subject of more recent development, apparently has not been incorporated into his theory. 

Balandin, A. A., Present State of the Multiplet Theory of Heterogeneous Catalysis. Nauka, Moscow (1968). 

Soon after the multiplet theory had appeared, Polanyi 34) advanced his theory of catalysis. It is based on quantum-mechanical assumptions, and conclusions from it are very similar to what the multiplet theory suggests and can virtually be interpreted by the index (I.l). The intermediate state according to Polanyi s theory is such a state at which the bonds A—B and C—D are completely broken, and the atoms A, B, C, and D are chemically bound with the valencies of the surface (Fig. 4). Polanyi points out (3<5), and with good reason, that the states (a)... 

Summing up the relations between the multiplet theory and the theory of intermediate surface compounds, one can come to the conclusion that both theories agree in the following They both consider that catalysis is brought about by chemical forces which yield some intermediate species forms. The main difference is that the multiplet theory deals with deformation and structural and energetic factors such as atomic radii and bond energies. Other differences have been pointed out above. Deformation of reacting molecules and bonds is the point that is common to the deformation theories of catalysis of Mendeleev, Zelinskii, and Bodenstein, developed and specified on the basis of modern data. 

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