Heterolytic dissociation of hydrogen

Scheme 10. Hydrogenation of olefin caused by heterolytic dissociation of hydrogen.

ELECTROSTATIC EFFECTS IN THE HETEROLYTIC DISSOCIATION OF HYDROGEN AT MAGNESIUM OXIDE... 

Abstract. An embedded-cluster approximation is adopted for simulating the heterolytic dissociation of hydrogen at two intrinsic defects on the (001) surface of magnesium oxide the isolated anion vacancy, and the tub divacancy. The dissociation process is shown to be critically dependent on the structure of the electrostatic field at the surface both as concerns energetics and final configuration. 

Electrostatic effects in the heterolytic dissociation of hydrogen at magnesium oxide 247... 

Intermediates which are involved in heterogeneous catalysis could have ionic character, which require an extention of the general treatment of complex reactions. As an example we can consider the catalytic hydrogenation over oxides and sulphides, where intermediates of cationic character were proposed. Ionic intermediates are also possible in catalysis over metals, for instance in the case of neopentane transformations over electron deficient palladium, which occur via formation of carbocations. If we consider olefin hydrogenation over oxides or sulphide with a heterolytic dissociation of hydrogen, the mechanismn of this reaction can be presented in the following form... 

Heterolytic dissociation of hydrogen on MgO surface is demonstrated by IR spectroscopy. IR bands of both O-H and Mg-H stretching are observed as shown in Fig. 3,9. 

The transition metal oxides form the other principal class of catalysts. These differ from the metals in that they have both acid and base sites in the same surface (the metal and oxygen atoms/ions, respectively) and react differently according to which of these properties is dominant. Figure 14 shows the infrared spectrum from the heterolytic dissociation of hydrogen on polycrystalline ZnO to given surface... 

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