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

Yuanhai Su and Volker HesselMicro Flow Chemistry and Process Technology, Dept. of Chemical Engineering and Chemistry, EindhovenUniversity of Technology, Den Dolech 2, 5600 MB Eindhoven, The NetherlandsTimothy No€elMicro Flow Chemistry and Process Technology, Dept. of Chemical Engineering and Chemistry, EindhovenUniversity of Technology, Den Dolech 2, 5600 MB Eindhoven, The NetherlandsDept. of Organic Chemistry, Ghent University, Krijgslaan 281 (S4), 9000 Gent, BelgiumDOI 10.1002/aic.14813Published online in Wiley Online Library (wileyonlinelibrary.com)A compact photomicroreactor assembly consisting of a capillary microreactor and small-scale light emitting diodes wasdeveloped for the study of reaction kinetics in the gas-liquid photocatalytic oxidation of thiophenol to phenyl disulfidewithin Taylor flow. The importance of photons was convincingly shown by a suction phenomenon due to the fast con-sumption of oxygen. Mass transfer limitations were evaluated and an operational zone without mass transfer effects waschosen to study reaction kinetics. Effects of photocatalyst loading and light sources on the reaction performance wereinvestigated. Reaction kinetic analysis was performed to obtain reaction orders with respect to both thiophenol and oxy-gen based on heterogeneous and homogeneous experimental results, respectively. The Hatta number further indicatedelimination of mass transfer limitations. Reaction rate constants at different photocatalyst loadings and different photonflux were calculated. Furthermore, the advantages of this photomicroreactor assembly for studying gas-liquid photocata-lytic reaction kinetics were demonstrated as compared with batch reactors.