Convergent synthesis of polyamide dendrimer using a continuous flow microreactor

Dendrimers are nanoscale macromolecules that have highly branched, core-shell structures. Higher generation dendrimers have close-packed peripheral functional groups and a hollow interior. The chemistry of the core and the terminal functionalities can be tailored according to the specific application. These structural characteristics provide room for the design of dendrimers to meet a wide set of supra-molecular recognition and hosting tasks. Dendrimers are synthesized in a stepwise manner to higher generations using a number of chemical reactions, so carrying out the synthesis in a conventional reactor is time-consuming. Therefore the dendrimer products are expensive. In this work, convergent synthesis of dendrimer was carried out in a continuous flow microreactor. Pure dendrons and dendrimers could be synthesized using the microreactors within seconds of residence time. In comparison, the conventional flask synthesis took several hours for a similar yield. The reaction kinetics of G1 dendron synthetic process was conducted using the microreactor and compared with the flask synthesis. The data indicated the reaction is in fact a fast one which suggested the flask synthesis is hindered by mass transfer.