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Mono-and bimolecular intrinsic rate constants for the conversion of n-hexane over H-Y, H-ZSM-5, and H-β zeolites were measured at 623 K by combining conventional catalytic techniques with gravimetric adsorption measurements. Since H-zeolites are catalytically active, their adsorption properties under reaction conditions could not be directly obtained. Rather, adsorption experiments were carried out on the H-zeolites at temperatures below the onset of catalytic activity (450-530 K). Thermodynamic adsorption constants for the H forms at 623 K were then obtained by extrapolation. In addition, the catalytically inactive Na forms were chosen to characterize the overall temperature dependence of n-hexane adsorption on ZSM-5, Y, and β zeolites in the range 450-623 K. For the cracking experiments, monomolecular conditions were ensured by choosing a low hexane pressure (<0.57 kPa) and short contact times. The intrinsic activity for mono-and bimolecular n-hexane cracking over the zeolites, after taking into account the amounts of adsorbed hydrocarbon, was in the order H-ZSM-5 > H-β > dealuminated H-Y . H-Y.

Adsorption of H 2 , N 2 , and CO on four different protonated zeolitessH-ZSM-5, H-β, H-Y, and dealuminated H-Ysat low temperatures was studied by transmission Fourier transform infrared spectroscopy. The introduction of the basic probe molecules caused a red-shift of the IR stretching bands of the zeolitic acidic OH groups. This perturbation, which is commonly interpreted as a hydrogen bonding between the acidic OH group and the adsorbate and often taken as a measure of the acidic strength, was then compared with intrinsic activities for the acid-catalyzed cracking of n-hexane previously published for the same zeolite samples. Catalytic and spectroscopic characterization of the acidity is consistent only within the same class of zeolites, e.g. comparison of differently pretreated faujasites. Spectroscopic and catalytic observations for different types of zeolites do not match perfectly, because additional effects, such as interactions of larger molecules with pore walls and the stabilization of transition states and intermediates, can influence the course of an acid-catalyzed reaction.

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The sections in this article are Introduction: From Industrial Electrochemistry to Electrocatalysis Catalysis in Organic Electrochemistry Synthesis of Adiponitrile The S imons Process Bleached Montan Wax—Regeneration of Chromic Acid Waste Water Treatment A Anodic Oxidation of Toxic compounds a  Creating Reactive Oxygen Surface Species b  Selective Conversion vs. Total Combustion c  Common Electrode Materials B Cathodic Reduction of Toxic Compounds Catalysis in Inorganic Electrochemistry Chloralkali Electrolysis A Electrocatalytically Activated Dimensionally Stable Chlorine‐Evolving Electrodes ( DSAs ) B Electrocatalysis of Anodic Chlorine Evolution at Ru O 2 Anodes C Details of the Electrocatalytic Process D Preparation and Formulation of the Coatings for DSAs E Lifetime of Dimensionally Stable Chlorine‐Evolving Anodes F The Cathode Reaction—Oxygen‐Depolarized Cathode ( ODC ) Electrolysis of Hydrochloric Acid Preparation of Oxygen‐Depolarized Cathodes First Industrial HCl Electrolysis Using ODCs Oxygen‐Depolarized Cathodes for Chloralkali Electrolysis Industrial Water Electrolysis A The Electrochemistry of Water Electrolysis B Alkaline Water Electrolysis C PEM Water Electrolysis D High‐Temperature Water Electrolysis Summary and Outlook