Programmable aerosol chemistry coupled to chemical imaging establishes a new arena for automated chemical synthesis and discovery†

Aerosols have emerged as a massively parallel reaction medium promising accelerated reactivity and unanticipated reactivity outcomes, yet exploration of these properties has so far only been confined to specific reactions. Wider deployment in chemical synthesis and discovery is impeded by the lack of a general-purpose formalism for conceiving multi-step chemical transformations in the aerosol medium and standardised building blocks to enable adaptation of existing synthesis procedures to execution in the inherently stochastic and inhomogeneous aerosol phase. Here we propose a framework based on programmable timed release of reagents as atomised solutions that provides the minimum necessary building blocks for synthesis in an automated aerosol reactor. This framework both connects synthesis in traditional bulk media with aerosols and lays the foundation for massively parallel discovery in airborne microdroplets. To validate our proposed formalism with a concrete methodology, we demonstrate a prototype open hardware platform and three examples of automated procedures. Further, we propose chemical imaging as a category of analytical methodology tailored to interrogation of aerosols. As a proof-of-principle demonstration, we use optical microscopy to detect reactivity in the resulting microdroplets and study the spatial distribution of their compositions in response to changes in the synthesis program.