Commercial-Scale Visible Light Trifluoromethylation of 2-Chlorothiophenol Using CF3I Gas

Despite the growth of photoredox methods in academia, application of photoredox at scale in the pharmaceutical and fine chemical industries has been slow. In this report, a photoredox trifluoromethylation of a thiophenol was modified from the original literature report, and the mechanism was investigated to define the key scale-up parameters. The mechanistic insight was leveraged in the design and execution of two different reactor designs: an LED-based plug flow photoreactor and a laser-based continuous stirred tank photoreactor. In one of the first examples of commercial-scale photoredox chemistry, the process was scaled to provide over 500 kg of the desired intermediate and amended to fully continuous manufacturing.