We report an automated microfluidic system for screening and optimization of chemical reactions performed inside microliter liquid droplets. The system offers precise control over generation, merging and flow of droplet “micro-reactors” and over reaction conditions, including the volumes of the reagents, temperature and time. The high level of control coupled with the ability to quickly screen multiple reaction conditions allow us to thoroughly monitor the impact of input parameters on the yield of the reaction. In addition, the reagent consumption is kept remarkably low. As an exemplary use of our system we demonstrate a comprehensive study of acid-catalyzed (para-toluenesulfonic acid, p-TsOH) model imine formation (condensation of ortho-nitrobenzaldehyde and phenylethylamine) in an organic solvent (ethanol). By use of novel screening methods described herein, we unfold that the acid-catalyzed model imine formation in the organic medium can be considered as an assembly of acid-mediated and non-catalyzed reactions, both of which accelerate with increasing temperature.

我们报告了一种自动微流控系统，用于筛选和优化微升液滴内进行的化学反应。该系统可对液滴“微反应器”的产生，合并和流动以及反应条件（包括试剂的体积，温度和时间）进行精确控制。高水平的控制能力以及快速筛选多种反应条件的能力使我们能够彻底监控输入参数对反应产率的影响。另外，试剂的消耗保持在非常低的水平。作为我们系统的示例使用，我们证明了对酸催化的（对甲苯磺酸，对-TsOH）模型亚胺形成（邻位缩合）的全面研究。-硝基苯甲醛和苯乙胺）在有机溶剂（乙醇）中。通过使用本文所述的新颖的筛选方法，我们揭示了有机介质中酸催化的模型亚胺的形成可以被认为是酸介导的反应和非催化反应的集合，两者均随着温度的升高而加速。