Synergistic effects in organic mixtures for enhanced catalytic hydrogenation and hydrodeoxygenation

The hydrogenation and hydrodeoxygenation (HDO) of organic mixtures are important processes in bio-oil conversion and plastics upcycling. Understanding how the presence of co-reactants in organic mixtures affects the kinetics is critical for designing reactors that can convert these mixtures into desired products. Here, we discuss cases in (electro)catalysis where the presence of a co-reactant R2 enhances the rate of hydrogenation or HDO of another reactant R1 beyond the rate if only R1 is present. We divide the discussion into simple and complex mutual influences. Simple mutual influences occur when the presence of R2 does not change the mechanism or values of rate constants of elementary steps for R1. A complex mutual influence of R2 on R1 occurs if the presence of R2 changes the rate constants of elementary steps involving R1. We discuss challenges and opportunities in discerning the different mutual influences and increasing their synergistic effects in organic mixtures. [Display omitted] Challenges and opportunities:•There is a practical need for the hydrogenation and hydrodeoxygenation of organic mixtures to value-added products such as fuels and chemicals•Organic mixtures may have simple or complex mutual influences that cause the catalytic rate and selectivity to be different compared to converting a single organic species•Future work should study the catalytic conversion of binary organic mixtures to elucidate the simple and complex mutual interactions We discuss cases where general intuition on how rates may change in organic mixtures is helpful and highlight situations where rates are accelerated in mixtures. Mutual influences between organics in mixtures have been shown to enhance the catalytic hydrogenation and hydrodeoxygenation of a reactant R1 in organic mixtures by up to a factor of three compared to the reactant R1 alone. More knowledge of mutual influences will aid the conversion of organic mixtures such as bio-oils to fuels and chemicals.