Elucidating structure–properties relations for the design of highly selective carbon-based HMF sorbents

Abstract

5-Hydroxymethyl furfural (HMF) production from fructose dehydration in DMSO with various catalytic systems has shown superior selectivity and high yields. Yet, the subsequent need for energy-intensive separation of HMF from HMF/fructose/DMSO mixtures challenges the practical feasibility of this process. Microporous carbon materials have shown promise as substrates for alternative adsorption-based separations, but the origin of HMF selectivity and adsorption capacity, and thereby structure–properties relations enabling rational design of enhanced sorbents, has remained elusive. Through systematic quantification of the functionality and texture of various commercial (BP2000, Norit1240) and synthetic carbons (three-dimensionally ordered macroporous carbons; mesoporous carbons), we link, for the first time, adsorption capacity and HMF adsorption selectivity to two tunable materials properties of the carbon sorbents: microporosity and oxygenate functionality (i.e., carbon polarity). In the process, we exploit these newly elucidated structure–properties relations for realizing a class of synthetic carbons with sub-micron particulate morphology that achieve more than 60% higher selectivity and more than 20% higher capacity for HMF over fructose as compared to the best performing commercial product, BP2000.