Resnick Institute Lecture

Mechanochemistry is a growing field that offers the promise of scalable syntheses without the use of solvents. Through the use of discrete element models and empirical measurements we have found that the reaction environment is a unique combination of high-pressure and low-temperature, a regime that has been poorly studied. We have used this insight to design catalysts specifically for use in mechanically induced reactions. The most efficient catalysts are based on solid structures with low dimensionality such as sheet silicates like kaolinite. Layered acidic catalysts can be used to mechanocatalytically depolymerize cellulose from any source. The pressures achieved during mechanical processing can exceed 0.6 GPa. This has allowed us to investigate unique reaction pathways, such as the f-block catalyzed retro aldol reaction of glucose and xylose to produce glyceraldehyde, glycoaldehyde, and dihydroxyacetone. These compounds can be produced from the same feedstocks used to produce biofuels and have a higher value than the sugars themselves. The realization of high value co-products will reduce the costsassociated with producing biofuels and accelerate their acceptance. Our approach is also feedstock independent, this will reduce the need for starch-based feedstocks such as corn. In order to expand the utility of this approach, we are now investigating hybrid catalysts that consist of active catalytic species tethered to robust sheet structures. These include silicates and oxidized graphite. Mechanochemical processes produce less waste and allow multiple products to be realized from a single source.