Liquid–Liquid Test Reactions to Characterize Two-Phase Mixing in Microchannels

Multiphase flow is often found in chemical engineering, food processing, or analytical devices. First contacting and droplet generation as well as coalescence and redispersion are important for the flow characteristics. In all processes, the channel geometry, fluid properties, and flow velocity determine the flow regime, droplet size, and interfacial area. The hydrolysis of alkyl acetates in organic phase with sodium hydroxide NaOH in the aqueous phase is investigated as flexible test reaction for mass transfer and interfacial area determination. The alkyl group is chosen from ethyl, isopropyl, or n-butyl, which differ in water solubility, diffusivity, and rate constant, for adequate design of the characteristic time for mass transfer. The consumption of NaOH is used for calculation of specific area and related mass transfer coefficient. Different channel geometries are characterized and design considerations are derived.

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