A compact photomicroreactor design for kinetic studies of gas‐liquid photocatalytic transformations

Abstract

A compact photomicroreactor assembly consisting of a capillary microreactor and small-scale LEDs was developed for the study of reaction kinetics in the gas-liquid photocatalytic oxidation of thiophenol to phenyl disulfide within Taylor flow. The importance of photons was convincingly shown by a suction phenomenon due to the fast consumption of oxygen.Mass transfer limitations were evaluated and an operational zone without mass transfer effects was chosen to study reaction kinetics. Effects of photocatalyst loading and light sources on the reaction performance were investigated. Reaction kinetic analysis was performed to obtain reaction orders with respect to both thiophenol and oxygen based on

Chemical reaction engineering, process design and scale-up issues at the frontier of synthesis: Flow chemistry

“…As described previously, scale-up and modelling of photo-microreacting systems is still in pioneering Furthermore, a photomicroreactor has been specifically designed for kinetic investigations by Su et al [145]. They considered as model reaction a gas-liquid one, i.e.…”

Local Mass Transfer Phenomena and Chemical Selectivity of Gas‐Liquid Reactions in Capillaries

“…These reactions are often limited by mass transfer or low chemical selectivity, which can be addressed by employing microstructured devices with high surface-to-volume ratio as well as enhanced mass and heat transfer [2]. Gas-liquid capillary flow with Taylor bubbles is frequently investigated and often employed in chemical synthesis [3,4]. Coiled capillaries can further increase the yield of gas-liquid reactions compared to straight capillaries as shown by Kurt et al [5].…”

Beyond Organometallic Flow Chemistry: The Principles Behind the Use of Continuous-Flow Reactors for Synthesis

“…For a simplified A→B reaction and under plug flow behavior, the rate equation can be described as follows: 137 () r LVRPA     (27) For the photocatalytic aerobic oxidation of thiols to disulfides, 138 Noël et al have investigated the effect of the photon flux on reaction yield: a clear effect can be seen on the reaction rate constant (Figure 12). 66,120 At low photon fluxes, no difference is noticed between a high and a low catalyst loading (Figure 12a). This indicates that the reaction occurs under a photon limited regime and the photons are constantly consumed to excite the photocatalyst.…”

“…Noël et al have calculated Ha for the photocatalytic aerobic oxidation of thiols to disulfides and found that the value was lower than 0.06. 66 This low value indicates that the reaction occurs in the bulk phase and that no mass transfer limitations are present in this gas-liquid photocatalytic process. The absence of mass transfer limitations allows one to determine intrinsic kinetics with microreactor technology.…”