Highly Efficient Asymmetric Paternò-Büchi Reaction in a Microcapillary Reactor Utilizing Slug Flow

Abstract

An asymmetric Paternò-Büchi-type photoreaction between 2,3-dimethyl-2-butene and benzoylformic acid ester with a chiral menthyl auxiliary was studied in a continuous-flow microcapillary reactor. The fluorinated ethylene propylene (FEP) microcapillary reactor using normal one-layer flow mode gave oxetane products with better efficiency than the batch system. In addition, the slug flow mode in microcapillary reactor using inactive reagent, N 2 gas or H 2 O, improved the reaction efficiency dramatically because of synergistic light dispersion, stirring and thin layer film effects. The reaction efficiencies under each condition were discussed as energy efficiencies calculated from reactors' parameters.

Photon Transport and Hydrodynamics in Gas‐Liquid Flows Part 1: Characterization of Taylor Flow in a Photo Microreactor

“…As can be seen in Figure , the variation found in our actinometric measurements is similar to the values obtained in the Paternò‐Büchi photoreactions by Terao et al . and Nakano et al .…”

“…They attributed this observation to the reduction of liquid mixing with increasing viscosity. Previously, they conducted investigations of the same type of reactions in toluene‐water Taylor flows . In this case, toluene was the phase that wetted the channel and water was the unreactive dispersed phase.…”

A revised 1D equivalent model for the determination of incident photon flux density in a continuous-flow LED-driven spiral-shaped microreactor using the actinometry method with Reinecke’s salt

“…Other authors have pointed out that using Taylor flows with an inert phase (i.e. an unreactive phase) dispersed in the continuous phase could be a promising way to achieve higher and selective conversions in the case of photochemical reactions, such as the Paterno-Büchi photoreaction or the [2 + 2] photocycloaddition of cinnamate [35][36][37][38].…”

Lattice-Boltzmann Simulation and Experimental Validation of a Microfluidic T-Junction for Slug Flow Generation

“…The scope of this study is droplet formation in a 1-mm channel geometry. In this range, droplet flow is successfully used in liquid/liquid systems for extraction [8][9][10] and synthesis of fine chemicals and pharmaceuticals [11][12][13][14]. In gas/liquid systems, applications include membrane fuel cells [15] and chemical synthesis [16][17][18].…”

“…For chemical synthesis, the short diffusion times for mass of process steps, faster exchange of matter, and reduction in chemical consumption, LLE in microsystems leads to highly efficient processes [8][9][10]. For chemical synthesis, the short diffusion times for mass and heat transfer lead to a new field of process intensification, which includes high temperatures, high pressures, and high concentrations (solvent-free) to explosive conditions [11][12][13][14]. To achieve highly productive microfluidic systems, a parallelization of the microchannel is crucial [19].…”