Microwave chemistry as a tool for flow chemistry processes
A complete chemical kinetic equation for maleic anhydride esterification with 2-ethyl hexanol was experimentally determined under conventional and microwave heating, with and without p-toluene sulfonic acid as a catalyst. These empirical equations were used for simulation of batch and plug flow reactors. Simulation results showed the feasibility of microwave application to this esterification, by analysing the efficiencies of the generators and the corresponding applicators against the microwave effect of reduced reaction time. The microwave heated reaction with 0.012 M of p-toluene sulfonic acid becomes so fast, that it may considered a flash reaction.
Exothermic, explosive and fast reactions have received special attention while pursuing safer and fast chemical processing. As a result, micro reactors and flow processing technologies were successfully developed (1-3). However, endothermic, non-explosive and slow reactions had not the same evolution and are still being processed in big batch reactors. This article highlights the microwave heating as an option to process intensification for these “pacific” reactions. Microwave energy usually accelerates chemical reactions (4, 5). An experimental study of maleic anhydride (MA) esterification by 2-ethyl hexanol (HEO) was done in order to demonstrate how microwave energy is capable of transform a batch process into a flow.
Simulation of reactors applying empirical complete chemical kinetic equations results under microwave and conventional electric heating, with and without p-toluene sulfonic acid (PTSA) as catalyst were done. The simulation results demonstrated that microwave chemistry might be a resource to apply flow chemistry to slow and endothermic reactions.
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