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Tube-in-tube flow reactors are emerging as a highly efficient flow chemistry strategy for performing various types of gas-liquid reactions due to their unique characteristics, such as high specific interfacial area, enhanced mass transfer and mixing, reduced material consumption, and safe handling of toxic and flammable gases. In this article we discuss the most recent advancements in utilizing tube-in-tube flow reactors for fundamental and applied studies of high-pressure gas-liquid reactions with carbon monoxide, hydrogen, and syngas. General guidelines for successful assembly of such flow chemistry platforms are discussed. In addition, a perspective on future potential directions for further development of the tube-in-tube flow reactors such as scale-up and increased robustness are provided. [ABSTRACT FROM AUTHOR]

We study microreactors with internal fields of posts as typical examples of structured microreactors to elucidate flow fields and their implications for mass transfer. Laser-induced fluorescence (LIF) visualization combined with image analysis is used to systematically quantify key features such as interfacial area, phase holdup and the characteristics of the post-wetting layer. The subsequent mass transport analysis yields insight into how the posts contribute to the overall enhanced mass transfer performance compared to open channels, and provides predictions of mass transfer performance under varying operating conditions. Computational fluid dynamic (CFD) simulations of multiphase flow using the volume-of-fluid (VOF) method are in good agreement with experimentally observed multiphase flows. [ABSTRACT FROM AUTHOR]

A multi-phase flow strategy, based on oscillatory motion of a bi-phasic slug within a fluorinated ethylene propylene (FEP) tubular reactor, under inert atmosphere, is designed and developed to address mixing and mass transfer limitations associated with continuous slug flow chemistry platforms for studies of bi-phasic catalytic reactions. The technique is exemplified with C–C and C–N Pd catalyzed coupling reactions. [ABSTRACT FROM AUTHOR]

Increase in the ionic strength of water that is mediated by the reaction of carbon dioxide (C 0 2) with nitrogenous bases is a promising approach toward phase separation in mixtures of water with organic solvents and potentially water purification. Conventional macroscale studies of this complicated process are challenging, due to its occurrence via several consecutive and concurrent steps, mass transfer limitation, and lack of control over gas—liquid interfaces. We report a new microfluidic strategy for fundamental studies of liquid—liquid phase separation mediated by CO2 as well as screening of the efficiency of nitrogenous agents. A single set of microfluidic experiments provided qualitative and quantitative information on the provided qualitative and quantitative information on the kinetics and completeness of water—tetrahydrofuran phase separation, the minimum amount of CO2 required to complete phase separation, the total CO2 uptake, and the rate of CO2 consumption by the liquid mixture. The efficiency of tertiary diamines with different lengths of alkyl chain was examined in a time- and labor-efficient manner and characterized with the proposed efficiency parameter. A wealth of information obtained using the MF methodology can facilitate the development of new additives for switchable solvents in green chemistry applications. [ABSTRACT FROM AUTHOR]