@article{davis_genzer_efimenko_abolhasani_2023, title={Continuous Ligand-Free Catalysis Using a Hybrid Polymer Network Support}, volume={7}, ISSN={["2691-3704"]}, url={https://doi.org/10.1021/jacsau.3c00261}, DOI={10.1021/jacsau.3c00261}, abstractNote={Although the pharmaceutical and fine chemical industries primarily utilize batch homogeneous reactions to carry out chemical transformations, emerging platforms seek to improve existing shortcomings by designing effective heterogeneous catalysis systems in continuous flow reactors. In this work, we present a versatile network-supported palladium (Pd) catalyst using a hybrid polymer of poly(methylvinylether-alt-maleic anhydride) and branched polyethyleneimine for intensified continuous flow synthesis of complex organic compounds via heterogeneous Suzuki–Miyaura cross-coupling and nitroarene hydrogenation reactions. The hydrophilicity of the hybrid polymer network facilitates the reagent mass transfer throughout the bulk of the catalyst particles. Through rapid automated exploration of the continuous and discrete parameters, as well as substrate scope screening, we identified optimal hybrid network-supported Pd catalyst composition and process parameters for Suzuki–Miyaura cross-coupling reactions of aryl bromides with steady-state yields up to 92% with a nominal residence time of 20 min. The developed heterogeneous catalytic system exhibits high activity and mechanical stability with no detectable Pd leaching at reaction temperatures up to 95 °C. Additionally, the versatility of the hybrid network-supported Pd catalyst is demonstrated by successfully performing continuous nitroarene hydrogenation with short residence times (<5 min) at room temperature. Room temperature hydrogenation yields of >99% were achieved in under 2 min nominal residence times with no leaching and catalyst deactivation for more than 20 h continuous time on stream. This catalytic system shows its industrial utility with significantly improved reaction yields of challenging substrates and its utility of environmentally-friendly solvent mixtures, high reusability, scalable and cost-effective synthesis, and multi-reaction successes.}, journal={JACS AU}, author={Davis, Bradley A. and Genzer, Jan and Efimenko, Kirill and Abolhasani, Milad}, year={2023}, month={Jul} }
 @article{davis_bennett_genzer_efimenko_abolhasani_2022, title={Intensified Hydrogenation in Flow Using a Poly(beta-cyclodextrin) Network-Supported Catalyst}, volume={11}, ISSN={["2168-0485"]}, url={https://doi.org/10.1021/acssuschemeng.2c05467}, DOI={10.1021/acssuschemeng.2c05467}, abstractNote={The intersection of heterogeneous catalysis and flow chemistry is of great importance for the emerging distributed manufacturing of specialty chemicals. Specifically, continuous production of aryl amines is an essential step for on-demand and on-site manufacturing of fine chemicals. This work presents a heterogeneous flow chemistry route for accelerated chemoselective hydrogenation of nitroarenes using a poly(β-cyclodextrin) network-supported palladium catalyst. The developed packed-bed flow reactor enables the selective hydrogenation of a rationally selected library of nitroarenes with >99% yield at room temperature and short residence times (1 min). Utilizing sodium borohydride as the hydrogen carrier in a pressurized packed-bed flow reactor allows safe and efficient delivery of hydrogen to nitroarene molecules. We demonstrate the robustness and versatility of the flow reactor packed with the network-supported catalyst through its consistently high reaction yield over a 3 day run and its reusability and stability in several solvent mixtures with a single-reactor aryl amine manufacturing throughput of up to 31.5 g/day. Furthermore, the catalytic packed-bed reactor is used in a case study for a two-step telescopic synthesis of a critical intermediate for the antibacterial drug linezolid, further supporting its utility as an industrially relevant catalyst for the broad application of catalytic hydrogenations in flow.}, journal={ACS SUSTAINABLE CHEMISTRY & ENGINEERING}, author={Davis, Bradley A. and Bennett, Jeffrey A. and Genzer, Jan and Efimenko, Kirill and Abolhasani, Milad}, year={2022}, month={Nov} }