(154a) Microreaction Engineering Chemistry in Flow for Sustainable Chemicals, Energy, and Healthcare
Flow chemistry, important to the global chemicals, energy, and healthcare segments, depends on the symbiosis between chemical reaction engineering and organic synthesis. The design of microchemical systems for reactions in flow impacts a broad cross-section of societal issues. Organometallic C-C and C-N bond formations, as examples, yield aryl heteroatoms for natural products, materials, and pharmaceuticals. Studying their chemical physics on-chip can accelerate research and manufacturing. Reductions in discovery times, solvent waste consumptions, and the energy requirements motivate the use of microsystems across multiple scales. However, the handling of insoluble inorganic salt by-products remains a major roadblock that commercial tubing does not resolve. Aqueous-phase catalyzed cross-couplings (e.g., Heck alkynylations) are partial solutions, but such reactions require understandings of the reaction and transport time scales. The application of traditional reaction engineering principles can help discover why water influences the catalysis of Heck alkynylations. Water influences the free energy barriers, and it potentially switches the mechanism. The resultant predictive kinetic models are also useful for greener scale-ups that reduce the E-factor.
On-chip investigations of natural macromolecular aromatics, as examples asphaltenes, directly impact hydrocarbon and natural gas productions. High-throughput packed-bed microreactors with online analytics generate scalable knowledge of asphaltenes accumulation mechanisms in unconsolidated, siliceous materials. Water also switches the accumulation mechanism. Flow and reaction in porous media, in general, is an important field that remains central to green chemistry and environmental sciences. Methane-water interactions with naturally derived macromolecules, as an example methane-cyclodextrin thermodynamics, are key to methane as a resource for chemicals, its natural sequestration, and polysaccharide aqueous chemistry that inhibits the formation of icy inclusion compounds. Transport limitations render kinetics of inclusion materials, such as hybrid cyclodextrin-gas hydrates, challenging to study. Their on-chip formation and dissociation directly impact the energy sector, yet the potential exists for use in chemo-selective reactive separations. Partnerships between scientists and engineers are needed to drive innovations in flow chemistry using microchemical systems and chemical reaction engineering is key to sustainability.