Fundamental Issues of Catalytic Conversion of Bio‐Ethanol into Butadiene

Ezinkwo, G.O.; Tretyakov, Valentine Philippovich; Aliyu, A.; Илолов, А. М.

doi:10.1002/cben.201400007

Cited by 30 publications

(35 citation statements)

References 31 publications

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“…Because the current form of the mechanism was first proposed by Kagan et al-subsequently modified by Niiyama et al, Natta et al and Bhattacharyya et al, it is referred as such in the present paper to distinguish it from the alternative mechanism [4,9]. The complete reaction pathway is believed to proceed as follows ( Figure 3): ethanol partially undergoes non-oxidative dehydrogenation, forming acetaldehyde (1); 3-hydroxybutanal (acetaldol) is produced by the adol condensation of two acetaldehyde molecules (2); acetaldol is dehydrated to acetaldehyde (3); crotonaldehyde is subjected to a Meerwein-Ponndorf-Verley-Oppenauer (MPVO) reduction involving ethanol, affording crotyl alcohol and acetaldehyde (4); crotyl alcohol is dehydrated to butadiene (5).…”

Section: The Kagan Mechanismmentioning

confidence: 99%

“…Both will be briefly discussed hereafter. Despite the debate between both mechanisms, the involvement of both ethanol and acetaldehyde in some steps of the reaction is well-established and not controversial [4,8,9]. In general, addition of acetaldehyde (in the two-step process) yields higher butadiene productivity [8].…”

Section: Generalities Mechanismmentioning

confidence: 99%

“…Promoters with redox properties (e.g., Ag, Cu, ZnO) have been repeatedly used to enhance the dehydrogenation of ethanol and increase the yield of butadiene in cases where these properties were absent or insufficient in the parent catalyst [4]. For instance, silica-supported tantalum oxide can become active for the Lebedev process with the use of copper to enable to conversion of ethanol to acetaldehyde [41].…”

Section: Catalyst Designmentioning

confidence: 99%

“…Fortunately, the dispersed literature has been summarized in review articles [4,[8][9][10]; the reader is referred to these publications for details concerning the history of the reaction, its fundamental principles, including mechanistic and thermodynamic considerations, the many catalytic systems studied and the issues regarding the design of new catalysts. Marked by the publication of "Investigation into the conversion of ethanol into 1,3-butadiene" in 2011 by Jones et al [11] the pace of scientific progress in the field of the ethanol-to-butadiene conversion has accelerated, as illustrated in Figure 1, which indicates the number of publications on the ethanol-tobutadiene reaction in the recent years.…”

Section: Scope Of the Reviewmentioning

confidence: 99%

“…At present, butadiene is predominantly extracted from the C4 steam cracker fractions [2]. Because the butadiene yield depends largely on the nature of the feedstock of the steam cracker, butadiene production is susceptible to market instability or trends in the petroleum industry, notably the emergent use of shale gas, which may lead to BD shortages [4]. The scarcity of greenhouse gas-emitting fossil fuel reserves is another long-term issue with the current butadiene production method, both in terms of commercial and environmental sustainability.…”

Section: Scope Of the Reviewmentioning

confidence: 99%

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Recent Breakthroughs in the Conversion of Ethanol to Butadiene

et al. 2016

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1,3-Butadiene is traditionally produced as a byproduct of ethylene production from steam crackers. What is unusual is that the alternative production route for this important commodity chemical via ethanol was developed a long time ago, before World War II. Currently, there is a renewed interest in the production of butadiene from biomass due to the general trend to replace oil in the chemical industry. This review describes the recent progress in the production of butadiene from ethanol (ETB) by one or two-step process through intermediate production of acetaldehyde with an emphasis on the new catalytic systems. The different catalysts for butadiene production are compared in terms of structure-catalytic performance relationship, highlighting the key issues and requirements for future developments. The main difficulty in this process is that basic, acid and redox properties have to be combined in one single catalyst for the reactions of condensation, dehydration and hydrogenation. Magnesium and zirconium-based catalysts in the form of oxides or recently proposed silicates and zeolites promoted by metals are prevailing for butadiene synthesis with the highest selectivity of 70% at high ethanol conversion. The major challenge for further application of the process is to increase the butadiene productivity and to enhance the catalyst lifetime by suppression of coke deposition with preservation of active sites.

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Section: The Kagan Mechanismmentioning

confidence: 99%

Section: Generalities Mechanismmentioning

confidence: 99%

Section: Catalyst Designmentioning

confidence: 99%

Section: Scope Of the Reviewmentioning

confidence: 99%

Section: Scope Of the Reviewmentioning

confidence: 99%

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Recent Breakthroughs in the Conversion of Ethanol to Butadiene

et al. 2016

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Synthesis of C₄ Olefins from Acetylene over Supported Copper Catalysts

2020

ChemCatChem

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Conversion of acetylene to C4 olefins enables on‐purpose synthesis of C4 olefins using abundant natural gas resource due to acetylene can be synthesized from methane or ethane. In this study, Cu‐based catalysts supported on SiO2, ZSM‐5 and mordenite (MOR) were tested for acetylene hydrodimerization. Effect of promoters including Ru, Ga, Ag and Pd on the acetylene conversion and C4 olefins selectivity are investigated. The structures of these catalysts were characterized by TEM, XRD, BET, H2‐TPR, NH3‐TPD and XPS measurements. Results showed that temperature, pressure and hydrogen partial pressure had positive effect on acetylene conversion. In the presence of Ru promotor, 100 % acetylene conversion and 87 % selectivity to C4 olefins were achieved over Cu/MOR catalyst under conditions of 0.1 MPa and 200 °C. The mechanistic aspect of acetylene hydrodimerization was elucidated where the C4 intermediate was formed by the reaction between [Cu]−C2H2 π‐complex and [Cu]−C2H2 σ‐complex which were transformed to 1,3‐butadiene and butene.

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Understanding the Deactivation of Ag−ZrO₂/SiO₂ Catalysts for the Single‐step Conversion of Ethanol to Butenes

et al. 2020

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Ag−ZrO2/SBA‐16 has recently been found to be efficient for catalyzing the single‐step conversion of ethanol to butene (1‐ and 2‐butene mixtures) in the presence of H2. The reaction proceeds via a cascading sequence of reactions over mixed metal and Lewis sites, with the catalyst composition tuned to selectively favor butene formation. However, the catalyst slowly deactivates when evaluated over long reaction times. In this work, we evaluated the lifetime of the Ag−ZrO2/SBA‐16 catalyst system for ethanol‐to‐butene conversion at 325 °C for up to 800 hours on stream. Several characterization techniques were used to elucidate the mechanism(s) by which catalyst deactivation occurs. Coke deposition, Ag particle sintering, and Ag0‐to‐Ag+ oxidation state change were identified to be the major causes of catalyst deactivation. Coke deposits cover primarily Lewis acid sites which are responsible for aldol condensation, Meerwein‐Ponndorf‐Verley (MPV) reduction, and dehydration reactions. Ag particle sintering and Ag oxidation state change leads to a reduction in the number of metallic Ag sites responsible for the dehydrogenation/hydrogenation steps. The fresh catalyst likely experiences hydrothermal sintering in the early stage of reaction and permanently loses some active Lewis acid sites before reaching a new structural steady state. The deactivation of Lewis acid sites leads to a decrease in overall ethanol conversion, whereas the deactivation of the metallic Ag sites decreases the butene selectivity. For catalyst regeneration, oxidative calcination (at 500 °C) followed by reduction (at 325 °C) successfully removes all the coke species on the catalyst surface and restores the metallic Ag particles of the 4Ag−4ZrO2/SBA‐16 catalysts.

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Fundamental Issues of Catalytic Conversion of Bio‐Ethanol into Butadiene

Cited by 30 publications

References 31 publications

Recent Breakthroughs in the Conversion of Ethanol to Butadiene

Recent Breakthroughs in the Conversion of Ethanol to Butadiene

Synthesis of C₄ Olefins from Acetylene over Supported Copper Catalysts

Understanding the Deactivation of Ag−ZrO₂/SiO₂ Catalysts for the Single‐step Conversion of Ethanol to Butenes

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Fundamental Issues of Catalytic Conversion of Bio‐Ethanol into Butadiene

Cited by 30 publications

References 31 publications

Recent Breakthroughs in the Conversion of Ethanol to Butadiene

Recent Breakthroughs in the Conversion of Ethanol to Butadiene

Synthesis of C4 Olefins from Acetylene over Supported Copper Catalysts

Understanding the Deactivation of Ag−ZrO2/SiO2 Catalysts for the Single‐step Conversion of Ethanol to Butenes

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Product

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Synthesis of C₄ Olefins from Acetylene over Supported Copper Catalysts

Understanding the Deactivation of Ag−ZrO₂/SiO₂ Catalysts for the Single‐step Conversion of Ethanol to Butenes