Heterogeneous Photochemical Process Intensification: Crystallization-Induced Dynamic Resolution of Amines

Area of Science:

• Chemical Engineering
• Photochemistry
• Crystallization

Background:

• Scaling up solid-containing photochemical reactions faces challenges like light scattering and mass transport limitations.
• Reactive crystallizations are valuable for driving equilibria and simplifying purification in chemical processes.
• In situ product precipitation can enhance reaction efficiency and product isolation.

Purpose of the Study:

• To implement and evaluate a photoredox-driven crystallization-induced dynamic resolution of a racemic amine on a multidecagram scale.
• To develop an intensified process by addressing challenges in solid-containing photochemical reactions.

Main Methods:

• Utilized a recirculating photoreactor system designed for solid-containing reaction mixtures.
• Integrated continuous filtration of crystallized product from the reaction slurry.
• Employed photoredox catalysis to drive the dynamic resolution process.

Main Results:

• Achieved successful multidecagram scale production of a resolved amine via crystallization-induced dynamic resolution.
• The recirculating photoreactor design mitigated light attenuation and reduced crystal holdup.
• Demonstrated a 1000-fold intensification compared to original batch conditions, with shortened reaction times and accelerated enantioenrichment.

Conclusions:

• The recirculating photoreactor system effectively overcomes scale-up limitations in solid-containing photochemical reactions.
• This approach enables highly intensified and efficient dynamic resolution processes.
• The technology offers a viable strategy for large-scale enantioselective synthesis.