Inversely Finding Peculiar Reaction Conditions toward Microfluidic Droplet Synthesis

Abstract

With the development of microfluidics, there are increasing reports of syntheses using not only conventional laminar flow at the microscale, but also the dissociation and aggregation of microdroplets. It is known, to some extent, that the microfluidics scale differs from normal scales in terms of the specific surface area, mass diffusion, and heat conduction; these are opposite to those in scale-up in-plant chemical engineering. However, it is not easy to determine what changes when the microdroplet flows through the channel. In this context, the author would like to clarify how the behavior of chemical species, which is expected to appear unique at the nanoscale, contributes to chemical reactions. What do we need in order to develop a completely new theory of chemical reactions? The characteristics of chemical reactions on the nanoscale are clarified via the encountering of solutions by the microfluidic device itself, or the chemical reaction of nanoscale droplets generated by the microfluidic device. Specifically, in recent years, experimental reports have accumulated that are expected to develop a fluidic device that can stably generate nanodroplets, and complex reactions of different reactivity are expected to occur that are specific to the nanoscale. In this short article, microfluidic devices, nanoscale droplets, experimental synthetic examples, and findings that may provide solutions are described.

Verification of the Inverse Scale Effect Hypothesis on Viscosity and Diffusion by Azo-Amino Acid Schiff Base Copper Complexes

“…The rate of crystal growth is adjusted by controlling the initial solution concentration, temperature, evaporation rate, etc., and it is generally good to set the time required for crystallization from several hours to several days. Indeed, we have obtained single crystals of "similar" copper(II) complexes suitable for X-ray analysis [21].…”

“…In order to test this hypothesis, in this study, we reexamined the polarization-induced molecular orientation in polymer films and then investigated the synthesis reaction of amino acid Schiff base copper(II) complexes on a beaker scale by adjusting the volume and viscosity of the solvent so that the reaction was unfavorable. We then decided to examine the conditions for growing single crystals of related complexes, where the azo group makes the solubility and crystal growth disadvantageous [21].…”