Transition Metal Free Alkyne Hydrogenation and Semihydrogenation Catalysts
Novel, transition metal-free catalysts capable of alkyne hydrogenation and semihydrogenation under modest conditions.
Numerous industrial processes require alkyne semihydrogenation or hydrogenation reactions. For example, hydrogenation is necessary for the industrial-scale synthesis vitamin A, the creation of high molecular weight polymers, and the processing of petroleum into functionally useful derivatives. Catalysts are typically employed to facilitate these reactions. However, existing catalysts suffer from several shortcomings: they are composed of expensive transition metals and require substantial energy input (in the form of high temperatures, pressures, or electrical overpotentials) to run. For example, the current industry standard catalyst for alkyne semihydrogenation requires palladium, which is one of the rarest and most expensive naturally occurring elements. Thus, there is a need for catalysts that utilize less energy and that are composed of less expensive, earth-abundant elements.
Researchers at The Ohio State University led by Dr. Joshua Goldberger have discovered a new family of Zintl phase, transition-metal free catalysts. Specifically, Dr. Goldberger and his team have developed a BaGa2 catalyst capable of alkyne hydrogenation and semihydrogenation at efficiencies rivaling that of commercial palladium-based catalysts. The researchers have demonstrated that this catalyst mediates hydrogenation of the alkyne-containing phenylacetylene into styrene and ethylbenzene (important industrial chemicals) even under modest pressure and temperature conditions. Furthermore, the catalyst has been shown to retain its activity even after multiple cycles. This family of catalysts promises to greatly reduce the financial and energy costs currently incurred during hydrogenation and semihydrogenation reactions, potentially impacting multiple industries.