Sustainable and\nAdvanced LED-Implanted Microfluidic\nPhotoreactor with Coupled Optical Fiber Enabling Efficient Photocatalytic\nSynthesis Beside Online Reaction Progress Monitoring

The conventional methods for the photoinduced synthesis\nof benzimidazoles\nmay need further improvement regarding a safer and energy-efficient\nsynthesis platform with in-process monitoring for maximum yield within\na much reduced reaction time. This work describes the use of a novel\noptofluidic Lab-on-a-Chip technology for safer, energy-efficient,\nand expedited synthesis of benzimidazole derivatives in excellent\nyields along with real-time quantitative measurement during product\nformation. This innovative method involves synthesis within LED-embedded\nmicrofluidic reactors, allowing for rapid synthesis of benzimidazole\nderivatives via photoinduced condensation cyclization reactions of\naryl aldehydes and <i>o</i>-phenylenediamines using a Rose\nBengal/fluorescein photocatalyst. It results in good to excellent\nyields (85–94%) in a notably shorter period of time (10 min)\nas compared to that for the batch protocol reaction (2–3 h).\nThe incorporation of a reaction-monitoring microfluidic device precisely\nconnected to the microfluidic reactor (microreactor) unit successfully\navoids interference from light sources, ensuring consistent UV–vis\nspectroscopic observations of the produced benzimidazole derivatives.\nThis LED-embedded microfluidic device’s capability of photoinduced\nsynthesis, along with real-time spectroscopic analysis, represents\na promising breakthrough in organic synthesis. The proposed approach\nminimizes the potential for accidents, prevents waste of chemicals,\nmaximizes atom economy, and designs an energy-efficient synthesis\nroute, along with real-time in-process monitoring.