Ethanol is a promising platform chemical for renewable production of a wide range of distillate fuels and chemicals. Continuing advancements in production efficiency and feedstock diversification will contribute to excess ethanol production past the “blend wall”, generating competitively priced feedstock for conversion to compounds traditionally derived from oil. While this provides an opportunity for producers of ethanol to expand their product offerings, robust processes for ethanol conversion to fuels and chemicals are currently deficient. We have recently developed a multifunctional catalyst system composed of metal-supported ZrO2/SiO2 with tailored metal and Lewis acid sites for producing either butadiene (BD) or n-butenes from ethanol with outstanding activity, selectivity, and stability. BD is a valuable precursor in the petrochemical industry used to produce many synthetic rubber materials. Producing BD from ethanol is beneficial as ethylene manufacturers, the main production source for BD, now produce less BD as a co-product due to a shift to lighter steam cracker feedstocks. Butenes are a high-volume commodity chemical useful in the production of distillate range fuels. The direct conversion of ethanol to n-butene-rich olefins is a significant improvement of the current state-of-the-art alcohol-to-jet process as it involves one less unit operation. Selectivity toward the targeted product is obtained by tuning the feed gas composition. Under N2, an ethanol conversion of 99% and selectivity of 71% to BD is obtained. Under H2, an ethanol conversion of 99% and selectivity of 88% to butene-rich olefins is achieved. Stability for 100+ h TOS is demonstrated for BD and n-butenes-rich olefins production. Insights into structure-activity relationships and the reaction mechanism were found through investigations using operando NMR, DFT, and in-situ XPS. In conclusion, the presented system is promising for the renewable production of BD or n-butenes-rich olefins from ethanol with its exceptional yield to products and stability under productive process conditions.

Tailored metal and Lewis-acid sites for the single-step conversion of ethanol to n-butene-rich olefins or butadiene over metal supported ZrO2/SiO2 catalysts

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.