Photochemical microfluidic synthesis of vitamin D3 by improved light sources with photoluminescent substrates

This study presents a novel technique for the controllable preparation of photoluminescent substrates to enhance the photochemical microfluidic synthesis of vitamin D-3. The dip-coating method to prepare the substrates was experimentally optimized, and the corresponding emission behaviors were systematically investigated. The substrates were successfully used to enhance the ultraviolet B (UVB) emission of a low-power light source (e.g., an 8 W lamp), whose UVB emission intensity was increased by approximately 11 times. By virtue of the novel light source, the productivity of a single set of photochemical microreactor with a 12-meter-long channel (0.6 mm i. d.) was increased to 1.83 kg.a(-1), which was 42% higher than that of a 100 W lamp, and no cooling devices were used. The method is simple and has great potential to replace traditional medium-pressure mercury lamps for UVB-irradiated photochemical reactions. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.