In a spin

Flasks have long been the fundamental piece of equipment for chemical syntheses and separations. In recent years, batch-reactor and flow-based systems have been created to run multistep processes without the need for manual handling or intermediates, but both approaches require a high degree of precision engineering to set up and control. In this week’s issue, Bartosz Grzybowski and his colleagues present rotating chemical reactors based on self-organizing concentric layers of immiscible or pairwise-immiscible liquids, each hundreds of micrometres to millimetres thick. Multiple steps in a process are dictated by the ordering of the layers and transport is facilitated by mixing through periodic variations in the reactor’s rotational speed. The team demonstrates the use of the liquid reactors in multistep chemical syntheses, simultaneous acid-base extractions and the separation of complex reaction mixtures.