Enhancement of Microfluidic Process with UVB-LED Lighting for Vitamin D₃ Synthesis

Ultraviolet B (UVB) irradiation is essential for vitamin D3 synthesis, and traditional mercury lamps have limited efficiency in this spectral region. Herein, an innovative method was presented for synthesizing vitamin D3 in a microreactor with UVB-LED lighting as the light source. Experimental optimization of the process conditions revealed a significant enhancement in reaction efficiency, achieving a 130-fold increase in just 30 s. The energy consumption for the process was reduced from 3.21 to 0.26 kWh/g. The development and validation of kinetic models are conducive to industrial process implementation and reactor design. The emission characteristics of the light sources were compared. Under UVB-LED lighting, the measured quantum yield of 0.655 significantly surpassed the 0.367 yield observed under mercury lamp lighting, resulting in an enhancement in the reaction efficiency. Emission spectrum test results corroborated a low byproduct yield of 8%.