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

Abstract

Photooxygenation reactions involving singlet oxygen (1O2) are utilized industrially as a mild and sustainable access to oxygenated products. Due to the usage of organic dyes as photosensitizers, these transformations can be successfully conducted using natural sunlight. Modern solar chemical reactors enable outdoor operations on the demonstration (multigram) to technical (multikilogram) scales and have subsequently been employed for the manufacturing of fine chemicals such as fragrances or biologically active compounds. This review will highlight examples of solar photooxygenations for the manufacturing of industrially relevant target compounds and will discuss current challenges and opportunities of this sustainable methodology.

Direct synthesis of oxaspirolactones in batch, photoflow, and silica gel-supported solvent-free conditionsviavisible-light photo- and heterogeneous Brønsted acid relay catalysis

“…To our delight, our protocol is indeed not only flexible, robust and operational even under alternative reaction set-ups or conditions but it is also simple and accessible, especially when using sunlight irradiation so specialized devices, such as concentrated solar reactors (CSR), are not needed. 38 However, the availability of appropriate weather conditions is a limiting factor for this strategy, thus reaction times could vary (see the ESI, section 5.2.3†). To address this issue, the feasibility of standard household fluorescent tubes as a light source for our reaction of interest was also investigated.…”

Development of an Off‐Grid Solar‐Powered Autonomous Chemical Mini‐Plant for Producing Fine Chemicals

“…Applying this easy‐to‐build system to a known industrial photochemical process, such as Dragoco's rose oxide synthesis,[ 40 , 41 ] can justify its use against other options. The key photooxidation can be performed under solar irradiation [42] and would benefit from our LSC‐PM technology.…”

Progress in Development of Photocatalytic Processes for Synthesis of Fuels and Organic Compounds under Outdoor Solar Light

“…Previously, there were successful attempts to utilize ICP/flatbed reactors for organic synthesis, but the concentrator-based process remains dominating in the field . A similar reactor is also operational in JCU in Townsville, Australia, using reflecting back surface and homogeneous catalysts . Still, there is a significant gap between current state-of-the-art flatbed photoreactors for organic syntheses and their industrial implementation as there are issues with poor mass transfer in laminar flow (in general) and in contact between the liquid phase and a catalyst (for reactors with heterogeneous catalyst bed).…”