Transition metals promoting Mg-Al mixed oxides for conversion of ethanol to butanol and other valuable products: Reaction pathways

Mück, Jáchym; Kocík, Jaroslav; Hájek, Martin; Tišler, Zdeněk; Frolich, Karel; Kašpárek, Aleš

doi:10.1016/j.apcata.2021.118380

Cited by 14 publications

(29 citation statements)

References 40 publications

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“…Obviously, the deconvolution Gaussian line shape of this profile accurately classified these acidic sites as two peaks of weak sites, one peak of medium sites, and a single peak of strong acidic sites (see Figure 7 b), as well as that peak of the physisorbed probe molecules of THF. Many published articles applied NH 3 ‐TPD technique[ 4 , 5 , 15 ] to classify the strength of the acidic sites, while others measured the IR‐spectra of pyridine[ 1 , 3 , 18 , 20 ] for the same purpose. Nothing was stated about quantitatively estimating the acidic sites with pyridine or using pyridine‐recorded DSC‐TPD profiles.…”

Section: Resultsmentioning

confidence: 99%

“…[3] Others demonstrated the NH 3 -TPD (Temperature-programmed desorption) profiles of Fe 2 O 3 nanoparticles supported on γ-χ-Al 2 O 3 , [4] and promoted MgÀ Al mixed oxides with transition metals. [5] Gafurov et al [6] employed electron paramagnetic resonance (EPR) measurements of 9,10anthraquinone as a probe molecule, as well as IR spectroscopy of CO, pyridine and NH 3 -TPD to successfully determine and differentiate between the strength of the surface Lewis acid centres of γ-alumina. They observed a good agreement between the EPR results of anthraquinone and the other exploited methods.…”

Section: Introductionmentioning

confidence: 99%

“…The above‐mentioned successful attempts,[ 1 , 2 , 3 , 4 , 5 , 6 , 7 ] which used different basic molecules, encourage us to investigate tetrahydrofuran (THF) as a probe molecule to determine acidic surface sites of our samples. Our research team has published numerous articles over the last two decades, including TPD studies of pyridine and NH 3 as probe molecules, as well as IR‐spectroscopy of pyridine[ 12 , 13 , 14 , 15 , 16 ] for the determination of the acidic sites of some catalysts.…”

Section: Introductionmentioning

confidence: 99%

“…The majority of the published articles employed the IR‐spectroscopic methods to characterise the surface acidity of solid catalysts such as: 12‐membered ring zeolites probed with 2,4,6‐tri‐ tert ‐butylpyridine, [1] TiO 2 ‐based solid catalysts by adsorption of NH 3 , [2] commercial samples of Faujasite‐type zeolite probed with six molecules as follows: pyridine, 2,6‐di‐ tert ‐butylpyridine, 2,4 dimethylquinoline, tributylamine, trihexylamine, and 2,4,6‐tri‐ tert ‐butylpyridine that with different basicities and critical diameters [3] . Others demonstrated the NH 3 ‐TPD (Temperature‐programmed desorption) profiles of Fe 2 O 3 nanoparticles supported on γ‐χ‐Al 2 O 3 , [4] and promoted Mg−Al mixed oxides with transition metals [5] . Gafurov et al [6] .…”

Section: Introductionmentioning

confidence: 99%

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Assessment of Lewis‐Acidic Surface Sites Using Tetrahydrofuran as a Suitable and Smart Probe Molecule

et al. 2022

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Measuring the Lewis‐acidic surface sites in catalysis is problematic when the material‘s surface area is very low (SBET ≤1 m2 ⋅ g−1). For the first time, a quantitative assessment of total acidic surface sites of very small surface area catalysts (MoO3 as pure and mixed with 5–30 % CdO (wt/wt), as well as CdO for comparison) was performed using a smart new probe molecule, tetrahydrofuran (THF). The results were nearly identical compared to using another commonly used probe molecule, pyridine. This audition is based on the limited values of the surface area of these samples that likely require a relatively moderate basic molecule as THF with pKb=16.08, rather than strong basic molecules such as NH3 (pKb=4.75) or pyridine (pKb=8.77). We propose mechanisms for the interaction of vapour phase molecules of THF with the Lewis‐cationic Mo and Cd atoms of these catalysts. Besides, dehydration of isopropyl alcohol was used as a probe reaction to investigate the catalytic activity of these catalysts to further support our findings in the case of THF in a temperature range of 175–300 °C. A good agreement between the obtained data of sample MoO3‐10 % CdO, which is characterised by the highest surface area value, the population of Lewis‐acidic sites and % selectivity of propylene at all the applied reaction temperatures was found.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Assessment of Lewis‐Acidic Surface Sites Using Tetrahydrofuran as a Suitable and Smart Probe Molecule

et al. 2022

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“…Traditionally, n-butanol is produced through fossil-based oxo process or the fermentation of sugar-containing crops (ABE process) [13,14]. Alternatively, with the increased availability of ethanol from biomass, the direct conversion of ethanol into butanol has been proposed to be an economical and sustainable route for butanol production [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Copper Supported on MgAlOx and ZnAlOx Porous Mixed-Oxides for Conversion of Bioethanol via Guerbet Coupling Reaction

Liu

Ding

et al. 2022

Catalysts

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The direct conversion of biomass-derived ethanol to high-valued-added chemicals has attracted widespread attention recently due to the great economic and environmental advantages. In the present study, the conversion of bioethanol through the Guerbet coupling process was studied in a fixed-bed reactor for MgAlOx and ZnAlOx mixed-oxides supported Cu catalysts. From the results, Cu adding into the system greatly enhance the dehydrogenation of ethanol and increase the H-transfer in the course of Guerbet coupling process. Simultaneously, the porous mixed-oxides provide the acid-base property of the catalysts for intermediate transformation. Notably, for Cu/MgAlOx, the main product of ethanol conversion is butanol, but for Cu/ZnAlOx, the primary product is ethyl acetate. Characterizations such as X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and CO2 temperature programmed desorption (TPD) were carried out to evaluate the structure and property of the catalysts. In combination with the catalytic performances with the characterization results, the synergistic catalytic effect between metal sites and acid-base sites were elaborated.

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The utilization of bio-ethanol for production of 1-butanol catalysed by Mg–Al mixed metal oxides enhanced by Cu or Co

Frolich

Malina

Hájek

et al. 2023

Clean Techn Environ Policy

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The Guerbet reaction is a possible way for transformation of ethanol to 1-butanol (important for many kinds of industries), which consists of four steps: dehydrogenation, aldol condensation, dehydration, and hydrogenation. Due to the elimination of possible side-reactions, the selective catalysis is required to favour production of 1-butanol at temperature below 350 °C. The main aim of this work was the ethanol transformation via heterogeneous catalysis using active Mg–Al mixed oxides with copper or cobalt carried out in the microflow reactor in the reaction temperature interval 280–350 °C. The novelty lies in the statistical analysis of results from characterization of catalyst structure and surface with catalysis results providing more sophisticated perspective on the ethanol valorization. The series of Mg–Al catalysts containing copper showed an overall higher conversion of ethanol and selectivity to butanol compared to the series containing cobalt. Major difference of catalytic activity was at low reaction temperatures and at a lower copper content in the Mg–Al matrix, which is significant from the point of view of environmentally clean processes. A multi-step mechanism of the Guerbet reaction involving an aldol condensation was verified for both tested catalysts series and reaction conditions. Graphic abstract

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Transition metals promoting Mg-Al mixed oxides for conversion of ethanol to butanol and other valuable products: Reaction pathways

Cited by 14 publications

References 40 publications

Assessment of Lewis‐Acidic Surface Sites Using Tetrahydrofuran as a Suitable and Smart Probe Molecule

Assessment of Lewis‐Acidic Surface Sites Using Tetrahydrofuran as a Suitable and Smart Probe Molecule

Copper Supported on MgAlOx and ZnAlOx Porous Mixed-Oxides for Conversion of Bioethanol via Guerbet Coupling Reaction

The utilization of bio-ethanol for production of 1-butanol catalysed by Mg–Al mixed metal oxides enhanced by Cu or Co

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