Abstract
We studied catalytic photooxidation with molecular oxygen to improve the characteristics of the existing oxidation reactions and have found several oxidation methods using mild conditions. These oxidations are appealing in terms of green chemistry since they reduce waste, use molecular oxygen, and do not require heavy metals; however, longer reaction times were required to accomplish them in batch reactions. This is due to both a small specific interfacial area and a large decrease in the energy of light traveling through the reaction mixture. With these reaction characteristics in mind, we designed a glass continuous flow microreactor that can form a slug flow region on the chip and irradiate light effectively at a very close distance. In slug flow, internal circulation, accelerating the mixing of the gas and liquid phases and increasing the reaction rate, occurs within a slug. Furthermore, internal circulation flow prevents the liberation of precipitate on the channel walls and causing blockages in the channel. We examined the development of our aerobic photooxidation with our continuous flow microreactor that can form a slug flow region on the chip, and solved problems raised by using batch system as mentioned above. Although many reaction devices designed for photoreactions have been studied previously, the glass continuous flow microreactor, which had not been studied yet, is a very suitable reaction device for photoreactions. Here we report our detailed study of aerobic photooxidation with this microreactor.
