Continuous-Flow Photochemical Transformations of 1,4-Naphthoquinones and Phthalimides in a Concentrating Solar Trough Reactor

Abstract

A series of photochemical transformations has been successfully conducted under continuous-flow conditions in a concentrating solar trough reactor. Photoacylations and [2+2]-photocycloadditions involving 1,4-naphthoquinones gave the corresponding photoproducts in moderate to high yields with residence times of 70min. Likewise, acetone-sensitized photodecarboxylations involving phthalimides furnished the corresponding benzylated hydroxy phthalimidines in good to excellent yields and purity with residence times of 40min. Compared with corresponding exposures to direct sunlight conducted in a solar float, flow operation generally gave superior conversions and subsequent yields.

Solar Photooxygenations for the Manufacturing of Fine Chemicals—Technologies and Applications

“…Visible-light photoredox catalysis, for example, has seen remarkable growth over the last decade [ 135 , 136 , 137 ], but no large-scale solar processes have been reported yet [ 138 ]. Likewise, new solar chemical reactor concepts have been recently developed, including continuous-flow trough and luminescent solar concentrators [ 139 , 140 , 141 ]. These chemical and technological advances have complemented past and existing activities in green photochemistry [ 142 , 143 , 144 , 145 , 146 , 147 , 148 ].…”