A transparent dual-channel microreactor with highly enhanced contact area-to-volume ratio was fabricated for efficient photosensitized oxygenations. The dual-channel microreactor shielded with polyvinylsilazane (PVSZ) consisting of an upper channel for liquid flow and a lower channel for O2 flow, allows sufficient phase contact along the parallel channels through a gas permeable PDMS membrane for maintaining the O2 saturated solution. Under full exposure of reactants to light, the reactions in high concentration are completed in minutes rather than hours that it takes to complete in a batch reactor. Moreover, the scale-up process using the microreactor revealed higher productivity than the batch reactor, which would be valuable for the practical applications in a broad range of gas–liquid chemical reactions.
