Search

The goal of this thesis research was to develop microfluidic platforms for the study of gas-solid and gas-liquid-solid alcohol oxidation reactions. The desired products of these reactions are of great importance industrially due to their value as intermediates in industries such as the fine chemical and pharmaceutical sectors. The application of microreaction technology to these reactions is proving to be beneficial due to their high surface area-to-volume ratio, resulting in fast heat and mass transfer and an ability to circumvent problems such as high exothermicity, mass transfer limitations, and poor control of reaction conditions. Two types of reaction systems were developed to facilitate this research; a three-phase micro-packed bed reactor for the study of benzyl alcohol oxidation on supported gold-palladium catalyst and a wall-coated microreactor for the study of methanol oxidation to formaldehyde on silver catalyst. Reaction and deactivation flow studies were first conducted in continuous flow microfluidic setups to understand catalyst activation and deactivation behaviour, culminating in the selection of the most stable catalyst formulation. These reaction studies were followed by a series of hydrodynamic and mass transfer investigations, where differences in hydrodynamics to conventional macroscale systems were identified, and a classification of flow regimes applicable to micro-packed bed reactors presented. An understanding of the influence of hydrodynamics on mass transfer, catalyst deactivation and reaction performance has been developed for benzyl alcohol oxidation, resulting in enhancement in flow reactor performance in comparison to batch. Exploration of different microreactor designs, to cope with challenging process conditions, as well as the application of novel methods for reactor characterization (such as Raman spectroscopy) are also presented.