ИСТИНА

The lecture provides a survey of the effects of microwave irradiation in catalyst preparation and catalytic processes. The existing technologies mostly reached the saturation level in their development and the further progress becomes possible, if at all, by using non-traditional approaches, such as the non-equilibrium conditions, gradient technologies, combination of endothermic and exothermic processes, ex-situ or in-situ application of electromagnetic activation modes, such as microwave activation, low-temperature plasma etc. Microwave technologies have been introduced as benign and robust approaches in quite many areas, including the industrial processes. Microwave irradiation (in the heating or plasma option) is widely explored in the processes of heavy oil and gas processing. It is obvious that in this case the dipolar polarization mechanism does not work and a conduction mechanism or Maxwell-Wagner effects can be responsible for the microwave heating. The microwave activation is widely used in the preparation of heterogeneous catalysts. The microwave activation of catalysts either at the stage of decomposition of precursors or further reduction allows the skillful scientists to prepare unique materials with very uniform distribution of supported metal or metal oxide nanoparticles in diverse (MW-absorbing or not) matrices. The MW-assisted preparation of catalysts allows one to accelerate the procedure. In the case of catalysts consisting of several phases, the replacement of traditional with microwave heating can contribute to the preferable formation of specific phases. Hydrogenation/dehydrogenation, cyclization, aromatization, methane conversion, organic syntheses and other processes are outlined from the viewpont of the application of microwave irradiation. Microwave radiation creating temperature gradients in a heterogeneous system whose components differently interact with electromagnetic fields can then cause substantial changes in the rate of the process and, which is especially important, distribution of reaction products. Though the oil processing under MW radiation is unlikely in the nearest future because of the upscaling problems, the use of MW-technologies for some gas processing is still quite perspective, because typically the volume of the reactors in these processes is much smaller compared to the oil processing and petrochemistry. Of course, this can be considered only for the processes and catalysts that have demonstrated significant advantages over the conventional thermal processes and the MW-conditions are optimized, including the operating frequency, input power, gas mixture flow rate, contact time and the configuration of the microwave electromagnetic field. Concerning the latter, a multi-mode reactor or a mono-mode resonator reactor can be used. There are also good grounds in certain instances for believing that catalytic processes of biomass and renewable conversion occur under the action of microwave fields differently than under traditional thermal activation with convective or conductive heating. The necessary conditions for the efficient action of a microwave field on a process is the strong interaction of a solid (a catalyst or its separate components, carbon species present in the biomass) or dipolar liquid components with this field.