The generation of high-value chemicals from renewable feedstocks presents a promising alternate route to routine production of chemicals from petroleum sources. Ethanol (ETH), as a potential renewable feedstock, has been identified as a versatile platform chemical for conversion and efficient integration of biofuels with bio-based products. Butadiene (BD) is an important building block chemical in the petrochemical industry with a worldwide production of 12 million tons/year. Currently, BD is primarily obtained as a by-product of the naphtha steam cracking process that is in decline due to the recent increase in shale gas production in the USA. The targeted conversion of ETH to BD has recently garnered much attention due to its economic feasibility, however, increasing the selectivity and yield of BD to industrially relevant throughputs is necessary to achieve commercial viability. Recently, we have developed a Ag-ZrO2/SiO2 catalyst enabling an ethanol conversion of 99% and a BD selectivity of 71%, thus providing an unprecedented yield to BD of 70% (325oC, 1 atm, 0.3 hr-1). In this talk, we discuss our findings on the structure-function relationships existing in the Ag-ZrO2/SiO2 that make it an effective catalyst for ETH to BD conversion. The individual contributions of this multifunctional catalyst are decoupled using first principles theoretical calculations to assess the independent and in-conjunction contributing role of the component to the reaction chemistry. Herein, we demonstrate how the amorphous SiO2 support and the interaction between the Ag and ZrO2 particles can strongly influence the catalytic reactivity and selectivity. By carefully considering the rational design space of this catalyst, we correlate the composition of the catalyst to the rate-limiting and selectivity determining steps in the transformation of ETH to BD.

Elucidating the multi-functionality of Ag-ZrO2/SiO2 catalysts in the single-step thermal conversion of ethanol to butadiene

256th National Meeting (2018)

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