Active sites in modified copper catalysts for selective liquid phase dehydration of aqueous glycerol to acetol

Mane, Rasika B.; Yamaguchi, Aritomo; Malawadkar, Atul V.; Shirai, Masayuki; Rode, Chandrashekhar V.

doi:10.1039/c3ra42348d

Cited by 36 publications

(32 citation statements)

References 41 publications

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“…However, copper-alkoxide species may also be produced by interaction with primary hydroxyl groups from glycerol to generate acetol. [8][9][10][11] On the other hand, the control of surface acid-base character of support for the copper based-catalysts plays an important role during the glycerol conversion to acetol. 5,[8][9][10][11] The most important disadvantage to the gas-phase transformation of glycerol to acetol, mainly on acid catalysts, is the deactivation due to extensive coke deposition on the catalyst surface, as well as the sintering process.…”

Section: Introductionmentioning

confidence: 99%

“…[8][9][10][11] On the other hand, the control of surface acid-base character of support for the copper based-catalysts plays an important role during the glycerol conversion to acetol. 5,[8][9][10][11] The most important disadvantage to the gas-phase transformation of glycerol to acetol, mainly on acid catalysts, is the deactivation due to extensive coke deposition on the catalyst surface, as well as the sintering process. 8,12 Therefore, the development of a catalyst resistant to deactivation by coke and the sample sintering during the conversion of glycerol to acetol in gas phase is one of the most interesting research challenges.…”

Section: Introductionmentioning

confidence: 99%

“…The glycerol dehydration proceeds through the formation of Cu-alkoxide species followed by hydrogen abstraction from the secondary hydroxyl groups. [8][9][10] The alkoxide generated from glycerol may release an OH radical from the primary OH groups to produce acetol. However, copper-alkoxide species may also be produced by interaction with primary hydroxyl groups from glycerol to generate acetol.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Non-Crystalline Copper Oxide Highly Dispersed on Mesoporous Alumina: Synthesis, Characterization and Catalytic Activity in Glycerol Conversion to Acetol

Braga¹,

Essayem²,

Valentini³

2016

Química Nova

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Polymeric precursor method and wet impregnation route were applied to synthesize copper and aluminium-based catalysts in order to obtain a material with interesting properties in catalytic reactions. The changes in the structural, morphological and textural properties due to the choice of preparation method were characterized by different techniques, such as XRD, N 2 physisorption isotherms and SEM. The XRD results of the solids present the formation of γ-Al 2 O 3 or CuO and β-Al(OH) 3 , depending on the preparation method. The average crystallite diameters of the alumina were estimated by the Scherrer's formula with a particle size of 5.2 nm. N 2 physisorption isotherms analysis shows that the alumina is a mesoporous material with a high specific surface area. An excessive increase in surface area was observed after Cu 2+ insertion by wet impregnation from β-Al(OH) 3 support, which is explained by the redissolution and recrystallization of bayerite to γ-Al 2 O 3 during the impregnation of Cu 2+ and recalcination process, respectively. The SEM images confirmed this phenomenon. Catalytic tests explain that the combination of the two methods improves the activity, selectivity and the stability in the conversion of glycerol to acetol. The results indicate that the way of catalyst preparation affects its structural, textural and morphological properties and consequently the catalytic performance.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Non-Crystalline Copper Oxide Highly Dispersed on Mesoporous Alumina: Synthesis, Characterization and Catalytic Activity in Glycerol Conversion to Acetol

Braga¹,

Essayem²,

Valentini³

2016

Química Nova

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“…In addition, Gabrysh et al. observed a very good linear correlation between the conversion of glycerol and the specific Cu surface derived from N 2 O frontal chromatography (Figure ), clearly indicating that the RDS can occur on a metallic Cu surface ,…”

Section: Deoxygenation Of Small Diols and Polyolsmentioning

confidence: 90%

Valorization of Biomass‐derived Small Oxygenates: Kinetics, Mechanisms and Site Requirements of H₂‐involved Hydrogenation and Deoxygenation Pathways over Heterogeneous Catalysts

Shi

2019

ChemCatChem

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Hydrodeoxygenation (HDO) is a key step in upgrading of biomass‐derived feedstocks to fuels and valuable chemicals. In this review, I select to discuss the current understanding of heterogeneous HDO catalysis of representative small oxygenates that are present in the bio‐crude obtained from thermochemical conversions of biomass raw materials, as the efficient valorization of these presently underutilized carbon sources would significantly improve carbon recovery and the overall process techno‐economics, in addition to facilitating downstream processing in some cases. A primary focus is laid on the kinetics, mechanisms and active site requirements of molecular H2‐involved hydrogenation and deoxygenation reactions of small aliphatic oxygenates. More often than not, surprising contrasts are found between gas‐solid and polar liquid‐solid interfaces and hint toward substantial restructuring and modifications of the catalytic surfaces and chemistries in polar liquids, particularly induced by protic molecules (the most abundant being water). Knowledge gaps, uncharted territories and associated challenges for the interrogations of these fundamental aspects are also discussed in this review.

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“…[33][34][35] It was already mentioned that the presence of Cu 0 /Cu I and the synergetic effect of Cu 0 and Cu + may favor the conversion of glycerol to acetol and 1,2-propanediol under specific reaction conditions. [36][37][38][39][40][41] Xiao et al 33 proposed that the metal copper was mainly responsible for the activation of hydrogen, while Cu + was for dehydration due to the presence of Lewis acid sites. The dehydration also takes place at metallic copper site, since glycerol may also be dehydrated to acetol.…”

Section: Temperature Programmed Reduction (Tpr)mentioning

confidence: 99%

Gas-Phase Conversion of Glycerol to Acetol: Influence of Support Acidity on the Catalytic Stability and Copper Surface Properties on the Activity

Braga¹,

Essayem²,

Prakash³

et al. 2016

Journal of the Brazilian Chemical Society

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Mesoporous mixed copper-aluminum oxides and copper-silicon oxides were synthesized with polymeric precursors route in order to evaluate the effect of the support acidity on the catalytic stability due to the carbon deposit and the copper surface characteristics on the catalytic activity for the gas-phase conversion of glycerol to acetol. The samples were characterized by different techniques such as inductively coupled plasma (ICP), thermogravimetry and differential thermal analyses (TGA-DTA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption isotherms, temperature-programmed reduction with H 2 (H 2 -TPR) and microcalorimetry of NH 3 adsorption. The metallic copper surface was shown by XPS, which was observed an increase with the copper loading without marked changes between Si or Al support using the same copper content. The Cu-Al catalysts present acidic properties close to that of the pure alumina support while the Cu-Si solid is not acid, as expected. Reduced catalysts were evaluated in the reaction of glycerol conversion. The catalytic results showed a clear dependence of the glycerol conversion to acetol with the Cu metal surface and the initial catalytic properties did not depend on the support acidity, since the copper is the major active site. It was observed 95% of acetol selectivity and 80% of glycerol conversion for the best catalyst. However, the support acidity influenced the catalyst stability, since Cu-Al solid deactivated continuously by contrast to Cu-Si sample, which reached stability after 2 h of reaction. The higher acidity for the Al support leads to a greater carbon deposit compared to Si support, blocking the active sites and providing a rapid catalytic deactivation.

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Active sites in modified copper catalysts for selective liquid phase dehydration of aqueous glycerol to acetol

Cited by 36 publications

References 41 publications

Non-Crystalline Copper Oxide Highly Dispersed on Mesoporous Alumina: Synthesis, Characterization and Catalytic Activity in Glycerol Conversion to Acetol

Non-Crystalline Copper Oxide Highly Dispersed on Mesoporous Alumina: Synthesis, Characterization and Catalytic Activity in Glycerol Conversion to Acetol

Valorization of Biomass‐derived Small Oxygenates: Kinetics, Mechanisms and Site Requirements of H₂‐involved Hydrogenation and Deoxygenation Pathways over Heterogeneous Catalysts

Gas-Phase Conversion of Glycerol to Acetol: Influence of Support Acidity on the Catalytic Stability and Copper Surface Properties on the Activity

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Active sites in modified copper catalysts for selective liquid phase dehydration of aqueous glycerol to acetol

Cited by 36 publications

References 41 publications

Non-Crystalline Copper Oxide Highly Dispersed on Mesoporous Alumina: Synthesis, Characterization and Catalytic Activity in Glycerol Conversion to Acetol

Non-Crystalline Copper Oxide Highly Dispersed on Mesoporous Alumina: Synthesis, Characterization and Catalytic Activity in Glycerol Conversion to Acetol

Valorization of Biomass‐derived Small Oxygenates: Kinetics, Mechanisms and Site Requirements of H2‐involved Hydrogenation and Deoxygenation Pathways over Heterogeneous Catalysts

Gas-Phase Conversion of Glycerol to Acetol: Influence of Support Acidity on the Catalytic Stability and Copper Surface Properties on the Activity

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Valorization of Biomass‐derived Small Oxygenates: Kinetics, Mechanisms and Site Requirements of H₂‐involved Hydrogenation and Deoxygenation Pathways over Heterogeneous Catalysts