Molecular structure effects of [N-R,N-222][Tf2N] ionic liquids on their flow properties in the microfluidic chip reactor-a complete validation study
Abstract
N-alkyl-triethylammonium bis(trifluoromethanesulfonyl)imides ([N-R,N-222][Tf2N]) ionic liquids (different in the length of their alkyl chain) are well suited for accommodating chiral catalytic organometallics in stereoselective hydrogenation reactions. It appears, particularly in the field of industrial fine chemistry that such transformations might be of high practical importance if performed in a microfluidic reactor space.
The inspected group of ionic liquids comprises two distinctive kinds of spatial domain the ionic and the non-polar one. Due to rising the C/H ratio, the non-polar character becomes more dominant and at a certain level the molecular character resembles rather the alkane than the ionic compound.
Such significant structural changes must be in some way reflected in flow properties of these ionic liquids, and their mixtures with other fluids inside of a narrow microreactor channel. The molecules with a straight tail may reveal flow properties very different from those with a twisted chain.
The term "very different" expresses a clear deviation from trends expected on the basis of their viscosity and density data measurements. The flow conditions were first optimized for a straight capillary, then the tests were transferred to a microfluidic space of a serpentine character, however of the same volume as the original capillary.
The main intention was to adapt the microfluidic reactor chip for practical utilization in reaction systems with various [N-R,N-222][Tf2N] ionic liquids.