Immobilised photosensitisers for continuous flow reactions of singlet oxygen in supercritical carbon dioxide

Abstract

Photosensitisers have been incorporated into both polymer and aerogel supports for the photochemical generation of singlet oxygen, ¹O₂, in supercritical carbon dioxide, scCO₂. These systems showed high activity and an acceptable lifetime for the photo-oxidation of α-terpinene and of citronellol in continuous reactors over a period of at least 5 h. The most effective photosensitiser was a covalently coupled analogue of tetradi(2,6)chloro-phenylporphyrin (TDCPP) on polyvinyl chloride (PVC). This immobilisation removes the need to separate the photosensitiser from the downstream solution.