Single-step Conversion of Methyl Ethyl Ketone to Olefins over Zn_xZr_yO_z Catalysts in Water [electronic resource]

• Ngôn ngữ: eng
• Ký hiệu phân loại: 666.3 Pottery
• Thông tin xuất bản: Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Energy Efficiency and Renewable Energy ; Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2019
• Mô tả vật lý: Size: p. 3393-3400 : , digital, PDF file.
• Bộ sưu tập: Metadata
• ID: 262831
• Chủ đề: 1. 09 biomass fuels; 2. 2,3-butanediol; 3. 37 inorganic, organic, physical, and analytical chemistry; 4. Methyl-ethyl-ketone; 5. Olefins

Tóm tắt

 In this study we investigated the conversion of aqueous methyl-ethyl-ketone (MEK) to olefin fuel precursors over Zn<
 sub>
 x<
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 Zr<
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 y<
 /sub>
 O<
 sub>
 z<
 /sub>
  mixed oxide catalysts. Experiments were carried out in water as MEK is intended to be produced from the dehydration of 2,3-butanediol in fermentation broth which is highly diluted in water. We demonstrated that Zn<
 sub>
 x<
 /sub>
 Zr<
 sub>
 y<
 /sub>
 O<
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 z<
 /sub>
  catalysts are highly effective for converting aqueous MEK to C<
 sub>
 4<
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 -C<
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 5<
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  olefins. High selectivity to olefins equal to 85% was reached at 92% per pass conversion when under H<
 sub>
 2<
 /sub>
  atmosphere. Catalyst stability was demonstrated for 60 hours' time on stream, highlighting the potential for upgrading 2,3-butanediol contained in fermentation broth without the need for energy-intensive water separation. Increased concentration of MEK in the aqueous feed results in increased activity towards olefin production. However, water inhibits catalyst deactivation from coking. A mechanistic investigation revealed the impact of the reaction environment (inert or reducing atmosphere) on the reaction pathways. In an inert environment, the mechanism involves consecutive aldol condensation of MEK and 3-pentanone intermediate. Under reducing conditions two reaction pathways compete with each other as MEK hydrogenation to butenes occurs concurrently with the aldol condensation/decomposition.