Segmented Tube Reactors (STR): A Simple Tool To Screen Multiple Reactions in Parallel in Batch Mode within a Single Tube

Abstract

A simple tool to perform multiple reactions in parallel in batch mode in static segments within a single tube is described. The Segmented Tube Reactor (STR) involves using syringe pumps to load a section of Teflon tubing with solutions of reaction components while forming a preprogrammed gradient of one of the components (e.g., equivalents, concentration) along its length. Simultaneously, a chemically inert spacer is loaded to break the gradient into discrete static segments. Ten or more distinct sets of conditions can be quickly set up in a single experiment. Although the STR is set up in flow mode, reactions occur in batch mode within the tubes, usually by heating the STR for a desired duration. Segments are then individually sampled and analyzed to identify the conditions that provide the best performance. The technology is translatable: the STR was employed to screen for preferred reaction stoichiometries that were then duplicated on larger scale in batch mode in traditional lab equipment.

Parallel multi-droplet platform for reaction kinetics and optimization

“… 28 For larger-scale reactions (on the order of a milliliter), well plate-style approaches with glass vials for broad chemical compatibility and a top-plate for sealing can be used to enable heating without solvent loss, 43 but the confinement of all reactions in the plate to one set of continuous reaction variables remains, at the expense of sampling for reaction kinetic analysis. An alternative approach involves generating unique reaction droplets sequentially in a tube by varying the amount of reagent injected into each droplet, 44 but the lack of total independence of the conditions of reactions running in parallel persists. To increase the “universality” of automated platforms, various types of automated modular platforms 45 (some of which autonomously rearrange themselves to suit chemistries and process sequences of interest 38 ) have been developed, but there remains a need to translate these concepts of universality to automation at the micro- and nanomole scale.…”