Abstract
Photocatalysis has progressed enormously over the last decade, with numerous applications in organic synthesis, where the energy of excited states is used to induce reactions involving intermediates that would be inaccessible by thermal means. However, the mechanistic details are often only sketchily explored, which can lead to some confusion. For example, the conversion of plastics by photocatalysts may prove useful in forming high value-added compounds whose production would justify the cost of waste treatment. Our results on the use of acridinium salts, known for their photoinduced electron transfer reactions, have shown that the formation of benzophenone from polystyrene takes place through the generation of reactive oxygen species (ROS), contrary to what was proposed. This knowledge is fundamental for optimizing processes with a view to industrial scale-up. Furthermore, although very useful from a synthetic point of view, photocatalytic processes have destructive effects on consumer products exposed to sunlight. This is particularly true for foods, whose organoleptic properties can be undesirably altered by exposure to light. Apart from physical protection (opaque containers, turning off the light), little is known about preventing photodegradation. We have undertaken to elucidate the mechanism responsible for the appearance of the light defect in Champagnes, to show the involvement of a dimeric radical cation intermediate. Are these advances enough to propose chemically-based protection strategies? Let's find out!
