1-Butanol synthesis from ethanol over strontium phosphate hydroxyapatite catalysts with various Sr/P ratios

Ogo, Shuhei; Onda, Ayumu; Iwasa, Yukina; Hara, Kenji; Fukuoka, Atsushi; Yanagisawa, Kazumichi

doi:10.1016/j.jcat.2012.08.019

Cited by 147 publications

(139 citation statements)

References 27 publications

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“…These observations rather support the importance of a hydride transfer mechanism on materials free of transition metals. Hydride transfer can be realized by either formation of adsorbed proton and hydride ions 73 (borrowing-hydrogen principle, Scheme 3A) or a direct hydrogen-transfer mechanism involving a hydride shift 105 (Scheme 3B) as in the case of the MPV reaction. In the next step (Scheme 2, R3), butyraldehyde is transformed via aldolization into 2-ethyl-3-hydroxyhexanal and subsequently dehydrated (Scheme 2, R4) to 2-ethyl-2-hexenal, the coupled α,β-unsaturated aldehyde.…”

Section: Reaction Mechanisms and Thermodynamic Considerationsmentioning

confidence: 99%

“…73,96 The overall conclusion remained the same: the more basic the catalyst is or the more basic sites the catalyst possesses, the higher the selectivity will be towards the Guerbet alcohol and the less the other side reactions will occur. The importance of acid-base bifunctionality has once more been confirmed in two recent papers.…”

mentioning

confidence: 96%

“…Many publications focus on the Guerbet selfcondensation of ethanol for the production of n-butanol and higher alcohols. [65][66][67][68][69][70][71][72][73][74][75][76][77][78] Just like ethanol, n-butanol can be used as a renewable fuel, yet in comparison with ethanol, it has a higher energy density, a lower volatility and a lower propensity to absorb water. Methanol on the other hand lacks a second carbon atom and cannot self-condensate by Guerbet condensation.…”

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confidence: 99%

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Review of catalytic systems and thermodynamics for the Guerbet condensation reaction and challenges for biomass valorization

Gabriëls

Hernández

Sels

et al. 2015

Catal. Sci. Technol.

249

233

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The Guerbet condensation reaction is an alcohol coupling reaction that has been known for more than a century. Because of the increasing availability of bio-based alcohol feedstock, this reaction is of growing importance and interest in terms of value chains of renewable chemical and biofuel production. Due to the specific branching pattern of the alcohol products, the Guerbet reaction has many interesting applications. In comparison to their linear isomers, branched-chain Guerbet alcohols have extremely low melting points and excellent fluidity. This review provides thermodynamic insights and unravels the various mechanistic steps involved. A comprehensive overview of the homogeneous, heterogeneous and combined homogeneous and heterogeneous catalytic systems described in published reports and patents is also given. Technological considerations, challenges and perspectives for the Guerbet chemistry are discussed.

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Section: Reaction Mechanisms and Thermodynamic Considerationsmentioning

confidence: 99%

mentioning

confidence: 96%

mentioning

confidence: 99%

See 1 more Smart Citation

Review of catalytic systems and thermodynamics for the Guerbet condensation reaction and challenges for biomass valorization

Gabriëls

Hernández

Sels

et al. 2015

Catal. Sci. Technol.

249

233

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“…No correlation was found between catalytic activity and the specific surface area. From earlier studies, 20,22 it is known that Sr-P hydroxyapatite catalyst is considerably more basic than the Ca-P, Ca-V, and Sr-V hydroxyapatite catalysts. Therefore, we concluded that Co catalyst supported on the more basic Sr-P hydroxyapatite support showed high catalytic activity for ethanol steam reforming.…”

Section: Ethanol Conversion ð%þ ¼mentioning

confidence: 99%

Coke Resistance of Sr-Hydroxyapatite Supported Co Catalyst for Ethanol Steam Reforming

2017

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Co/Sr-hydroxyapatite catalyst (Co/Sr 10 (PO 4 ) 6 (OH) 2 : Co/ Sr-P) shows high activity and low carbon formation on ethanol steam reforming. H 2 -TPR measurements revealed that the Co species supported on Co/Sr-P was reduced only slightly more than that on typical Co/α-Al 2 O 3 . XAFS measurements revealed that Co 2+ species was observed mainly on the Co/Sr-P catalyst after H 2 -reduction at reaction temperature of 823 K. Co 2+ , i.e. CoO particle, on Co/Sr-P catalyst plays an important role as an active site for ethanol steam reforming with high coke resistance.Keywords: Hydrogen production | Hydroxyapatite support | Coke resistanceBiomass-derived ethanol (bioethanol) is anticipated as an important renewable resource.1 Especially, direct production of hydrogen by ethanol steam reforming is being developed intensively as a highly efficient energy production process. 2,3Moreover, since ethanol steam reforming is an endothermic reaction, as shown in eq 1, the reformate has a higher heating value of about 1450.9 kJ mol ¹1 (1277.4 for ethanol ¦H c + 173.5) after ethanol steam reforming. Therefore, ethanol steam reforming might increase the exergy rate considerably. 4 The exergy rate is defined as the ratio of Gibbs free energy (potential useful work) over the combustion enthalpy (energy supplied). Development of highly active and selective catalysts for ethanol steam reforming has been pursued actively. Among transition-metal catalysts, Co-based catalysts have been used extensively because of their higher activity and lower cost than those of noble metal catalysts.511 However, catalyst deactivation by coke formation presents an important difficulty. Therefore, the suppression of coke formation is strongly desired. Two solutions have been proposed for suppressing coke formation in ethanol steam reforming over Co-based catalysts: addition of another element 8,1014 and controlling the catalytic support. 6,7,1416 Reportedly, the use of basic supports (CeO 2 , ZnO, Mg-Al hydrotalcite, perovskite oxides, etc.) can suppress formations of coke and by-products effectively. The substituted hydroxyapatite supports were prepared using a hydrothermal method according to a published procedure with some modifications. 2022 The crystalline structure was confirmed using powder X-ray diffractometry (XRD). These XRD patterns were attributed to each hydroxyapatite with a single phase (not shown). Samples of the prepared M-phosphate and M-vanadate hydroxyapatite (M = Ca and Sr) supports are designated as Ca-P, Sr-P, Ca-V, and Sr-V.The Co catalysts supported on the hydroxyapatite supports were prepared using an impregnation method. Co(NO 3 ) 2 ¢6H 2 O was used as a metal precursor. The Co loading amount was 5 wt %. The hydroxyapatite support was mixed with distilled water in vacuo at room temperature for 2 h using a rotary evaporator. Then aqueous solution of Co precursor was added and stirred for 2 h. The obtained solution was then evaporated under heating and stirring. Subsequently, the obtained powder was dried at 393 K overnigh...

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“…Marcel Guerbet first published on the alcohol coupling reaction in the 1890s [1], and ethanol coupling has been patented since the 1930's [3,4]. Coupling of short chain alcohols over heterogeneous catalysts has been the focus of recent works as well [29,31,32,46,55,69,74,180,181], in part due to a desire to produce chemicals and fuels from renewable feedstocks.…”

Section: Introductionmentioning

confidence: 99%

Carbon-Carbon Bond Forming Reactions Over Metal Oxide Catalysts

Kozlowski¹

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Alcohol coupling, also known as the Guerbet reaction, is a potentially important process to increase the value of short chain alcohols. Metal oxides, metal phosphates and supported transition metals like copper are some examples of heterogeneous catalysts for the reaction.However, the wide variety of catalyst compositions, reaction conditions, and reactor configurations used to study the reaction complicates a direct comparison of various catalysts.Herein, rates over different catalysts will be compared. One existing gap in the current literature is a thorough comparison of the surface acid and base properties of catalysts employed in the Guerbet coupling of alcohols. In this work, various bifunctional materials were synthesized, characterized, and used in Guerbet alcohol coupling and other probe reactions of acid and base catalysts.One well-studied reaction catalyzed by acids and bases is transesterification. Two series of Mg:Zr mixed oxides, prepared by either co-precipitation or sol-gel synthesis, were characterized and evaluated in the base-catalyzed transesterification of tributyrin with methanol.A co-precipitated Mg-rich mixed oxide catalyst with Mg:Zr 11:1 was approximately 300% more active than MgO on a surface area basis, whereas pure ZrO 2 was inactive for the reaction. To explore the nature of the activity enhancement, samples were characterized by X-ray diffraction, N 2 adsorption, CO 2 adsorption microcalorimetry and DRIFTS of adsorbed CO 2 and CH 3 OH.Although the sol-gel synthesis method provided better atomic-level mixing of Mg and Zr, the resulting catalysts were not as effective as mixed oxides prepared by co-precipitation. The most active mixed oxide (Mg:Zr 11:1) exhibited a high initial heat of CO 2 adsorption and modified modes of methanol adsorption compared to MgO. However, the CO 2 adsorption capacity did not correlate to catalyst activity.

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1-Butanol synthesis from ethanol over strontium phosphate hydroxyapatite catalysts with various Sr/P ratios

Cited by 147 publications

References 27 publications

Review of catalytic systems and thermodynamics for the Guerbet condensation reaction and challenges for biomass valorization

Review of catalytic systems and thermodynamics for the Guerbet condensation reaction and challenges for biomass valorization

Coke Resistance of Sr-Hydroxyapatite Supported Co Catalyst for Ethanol Steam Reforming

Carbon-Carbon Bond Forming Reactions Over Metal Oxide Catalysts

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