Abstract

Continuous-flow Photochemistry - Photochemistry 2.0?

Clemens Horn, Research Scientist, Corning SAS

Photochemistry in batch has not changed since days of G. Ciamician. A light source is placed into a reactor. Or with other words a substance is exposed for a defined time to a variable power of light of different wavelengths, since the batch is stirred and in most of the cases a mercury lamp is used as light source. Flow photochemistry is different. The distance to the light source varies much less due to the channel height. Therefore all molecules obtain a much more constant exposure to a much narrower power distribution of a narrower wavelength range than in batch. In case of a LED source the light is much “cleaner” and can be precisely dosed. The results presented show the advantage of flow photochemistry. They show how fast and easy photochemical reactions can be screened with a high performing setup. The setup used contains a multi wavelength reactor and online NMR. This allows screening various wavelengths without any change of light source and the online NMR delivers within 10 sec the results.