Photoresponsive microfluidic three-phase emulsions for tandem reactions

The long-term objective of tandem reaction is to investigate ‘intelligent’ tandem reaction systems akin to living cells. Here we’ve prepared an ‘intelligent’ droplet microreactor for the tandem reaction using droplet microfluidic technology constructing a photoresponsive microfluidic tandem reaction system. The method leverages a three-phase emulsion’s ‘two membranes and three phases’ structure to segregate incompatible reagents, and introduces a stimulating surfactant to control the structure of this emulsion structure for intelligent reaction sequence control, enabling efficient, orderly tandem reaction within the same system. Validating this concept, we applied the droplet microreactor to the condensation-reduction cascade reaction, as envisioned, incompatible condensation and reduction reactions, were coordinated by cycling the UV light on /off for a smooth cascade reaction. Compared to batch reaction, the droplet microreactor showed sixfold catalytic efficiency enhancement and > 99 % reaction selectivity. Our work offers novel insights into realizing intelligent cascade reactions.