2 research outputs found
Switchable Water: Microfluidic Investigation of Liquid–Liquid Phase Separation Mediated by Carbon Dioxide
Increase
in the ionic strength of water that is mediated by the
reaction of carbon dioxide (CO<sub>2</sub>) 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 CO<sub>2</sub> as well as screening of
the efficiency of nitrogenous agents. A single set of microfluidic
experiments provided qualitative and quantitative information on the
kinetics and completeness of water–tetrahydrofuran phase separation,
the minimum amount of CO<sub>2</sub> required to complete phase separation,
the total CO<sub>2</sub> uptake, and the rate of CO<sub>2</sub> 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
Metal-Free Catalytic Hydrogenation of Polar Substrates by Frustrated Lewis Pairs
In 2006, our group reported the first metal-free systems that reversibly activate hydrogen. This finding was extended to the discovery of “frustrated Lewis pair” (FLP) catalysts for hydrogenation. It is this catalysis that is the focal point of this article. The development and applications of such FLP hydrogenation catalysts are reviewed, and some previously unpublished data are reported. The scope of the substrates is expanded. Optimal conditions and functional group tolerance are considered and applied to targets of potential commercial significance. Recent developments in asymmetric FLP hydrogenations are also reviewed. The future of FLP hydrogenation catalysts is considered