Imidazolium Catalysts Formed by an Iterative Synthetic Process as a Model System for Chemical Evolution
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Processes exhibiting diversity and selection would have been necessary to promote chemical evolution on early Earth. In this work, a model process was developed using non-kinetic selection to synthesize and isolate small molecule imidazolium catalysts. These catalysts were purified by affinity chromatography and recycled back into the process, forming a product feedback loop. In dimethylformamide, the catalysts activated the coupling of formaldehyde to short chain sugars. This sugar mixture was reacted with aniline, acetic acid, and paraformaldehyde to generate new catalysts. Thus chemical diversity was produced through non-selective, multi-component synthesis. Applying sequential dilution-reaction-purification cycles it was demonstrated that this process can function independently of starting catalyst. Over three process cycles, the initiator catalyst is effectively diluted out as a new catalyst population emerges to take its place. This system offers an alternative viewpoint for chemical evolution via the generation of small molecule organocatalysts.
KeywordsImidazolium Catalysis Process chemistry Evolution Sugars
Ryan Clairmont graciously thanks Dr. Ram Krishnamurthy and Dr. Charlie Liotta for helpful discussions, Anthony Thompson Jr and Christine Conwell for their indispensable support, and many colleagues for productive advice: Beth Cope, Chris Butch, Jon Park, “T” Rubin, “Mick” Robbins, Steph Didas, and Justin Vaughn. The work was jointly supported by the National Science Foundation and the National Aeronautics and Space Administration Exobiology Program, under the NSF-Center for Chemical Evolution, CHE-1004570.
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