Microfluidic synthesis of elastomeric microparticles: A case study in catalysis of palladium‐mediated cross‐coupling

• Published in: AIChE journal 2018-08, Vol.64 (8), p.3188-3197
• Main Authors: Bennett, Jeffrey A., Kristof, Andrew J., Vasudevan, Vishal, Genzer, Jan, Srogl, Jiri, Abolhasani, Milad
• Format: Article
• Language: English
• Subjects: Annular flow; Capillary flow; Case studies; Catalysis; Catalysts; Chemical synthesis; Coaxial flow; Coupling; cross‐coupling; Dilution; Elasticity; Elastomers; Flow rates; Flow velocity; interfacial processes; microfluidics; Microparticles; multiphase flow; Organic chemistry; Packed beds; Palladium; polymerization; Polymers; reactor analysis
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.16119

Palladium (Pd)‐loaded poly‐hydromethylsiloxane (PHMS) microparticles of tunable size and elasticity are prepared in a capillary‐based coaxial flow‐focusing microfluidic device constructed using off‐the‐shelf components. Simultaneous droplet formation and chemical cross‐linking processes are performed by tuning the dilution of the cross‐linking catalyst in the annular flow of the microreactor, resulting in PHMS microparticles synthesized in a single step. The size of the elastomeric microparticles can be tuned by adjusting the flow rate ratio of the polymer and cross‐linker mixture to water, while the elasticity can be tuned by the polymer to cross‐linker ratio as well as the flow rate ratio of the polymer mixture to cross‐linking catalyst mixture. Microparticle elasticity is characterized by the degree of solvent uptake. Application of the synthesized PHMS microparticles in organic synthesis is demonstrated by producing monodispersed Pd‐loaded microparticles and utilizing them as microreaction vessels for continuous Suzuki‐Miyaura cross‐coupling in a Pd‐loaded microparticle‐packed bed reactor. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3188–3197, 2018