Evolution of Catalysts Directed by Genetic Algorithms in a Plug-Based Microfluidic Device Tested with Oxidation of Methane by Oxygen

Abstract

This paper uses microfluidics to implement genetic algorithms (GA) to discover new homogeneous catalysts using the oxidation of methane by molecular oxygen as a model system. The parameters of the GA were the catalyst, a cocatalyst capable of using molecular oxygen as the terminal oxidant, and ligands that could tune the catalytic system. The GA required running hundreds of reactions to discover and optimize catalyst systems of high fitness, and microfluidics enabled these numerous reactions to be run in parallel. The small scale and volumes of microfluidics offer significant safety benefits. The microfluidic system included methods to form diverse arrays of plugs containing catalysts, introduce gaseous reagents at high pressure, run reactions in parallel, and detect catalyst activity using an in situ indicator system. Platinum(II) was identified as an active catalyst, and iron (II) and the polyoxometalate H 5 PMo 10 V 2 O 40 (POM-V2) were identified as active cocatalysts. The Pt/Fe system was further optimized and characterized using NMR experiments. After optimization, turnover numbers of approximately 50 were achieved with approximately equal production of methanol and formic acid. The Pt/Fe system demonstrated the compatibility of iron with the entire catalytic cycle. This approach of GA-guided evolution has the potential to accelerate discovery in catalysis and other areas where exploration of chemical space is essential, including optimization of materials for hydrogen storage and CO 2 capture and modifications.

Liquid phase oxidation chemistry in continuous-flow microreactors

“…The group of Ismagilov used this evolution protocol to determine a new generation of active homogeneous catalyst systems for the aerobic oxidation of methane to methanol. 162 Parameters chosen were the catalysts itself (gene A), co-catalysts (gene B) and ligands (gene C). Microfluidic devices were used in order to run numerous reactions in parallel while minimizing consumption of reagents, reducing waste and improving safety.…”

Catalytic Oxy‐Functionalization of Methane and Other Hydrocarbons: Fundamental Advancements and New Strategies

“…The requirement of two oxidation states has been a particularly vexing issue with these systems, and the development of processes with oxidants other than Pt IV has been challenging. [20,54,55] Periana et al developed an alternative to Pt IV as a stoichiometric oxidant in Pt-catalyzed methane functionalization. [14] The reaction of methane in sulfuric acid catalyzed by (bpym)PtCl 2 (bpym = 2,2'-bipyrimidine) produces methyl bisulfate in greater than 70 % yield based on methane [Equation (2)].…”

Droplet Microfluidics as a Tool for the Generation of Granular Matters and Functional Emulsions

“…The high-throughput and spatial separation of samples make droplet microfluidics perfectly suitable for discovery chemistry-screening the libraries of compounds in search of, e.g. new catalysts (Goodell et al, 2009;Kreutz et al, 2010). Droplet microfluidics is also a perfect tool to investigate the chemical communication of compartments comprising chemical oscillators such as the Belousov-Zhabotinsky reaction (Guzowski et al, 2016).…”