As expected, with longer residence times, i.e. with lower liquid flowrates, the yield was improved. This result was similar to what was obtained in the microreactor. However, we observed that the rotation speed had a huge influence on yield and selectivity. This is most likely due to the improvements in mass transfer and the more effective mixing that occurs with high rotation speeds. With more effective mixing, we ensure that an excited oxygen species is more efficient in meeting a substrate before falling back to its ground state, i.e. within 16 µs. Similarly, with higher mass transfer rates, we can guarantee that the maximum dissolved oxygen concentration is reached quickly, and that the oxygen consumed due to reaction, can be quickly replenished in the liquid phase. This assures that we reach as close to intrinsic kinetic rates as possible. Furthermore, it is possible that with a higher turnover rate of the liquid close to the quartz plate, the light penetration improves, therefore also improving the yields.