Catalytic upgrading of biomass pyrolysis vapors and model compounds using niobia supported Pd catalyst

Teles, Camila A.; Souza, Priscilla M. de; Rabelo‐Neto, Raimundo C.; Griffin, Michael B.; Mukarakate, Calvin; Orton, Kellene A.; Resasco, Daniel E.; Noronha, Fábio B.

doi:10.1016/j.apcatb.2018.06.073

Cited by 86 publications

(55 citation statements)

References 48 publications

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“…According to the published literature, the acidic strength of active sites on the materials can be classified depending on the desorption temperature of NH 3 upon heating the sample under inert atmosphere [ 40 , 57 ]. Thus, the desorption of NH 3 in the range of 150–250 °C describes weak acid sites, 250–350 °C belongs to medium acid sites and above 350 °C corresponds to strong acid sites [ 57 , 58 ]. The results depicted in Figure 4 demonstrate that Nb 2 O 5 _SA contained medium and strong acid sites, whereas weak, medium and strong acid sites were present on Nb 2 O 5 _300_air.…”

Section: Resultsmentioning

confidence: 99%

Impact of Thermal Treatment of Nb2O5 on Its Performance in Glucose Dehydration to 5-Hydroxymethylfurfural in Water

et al. 2020

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The cascade dehydration of glucose to 5-hydroxymethylfurfural (HMF) was carried out in water over a series of Nb2O5 catalysts, which were derived from the thermal treatment of niobic acid at 300 and 550 °C, under air or inert atmosphere. Amorphous niobic acid showed high surface area (366 m2/g) and large acidity (2.35 mmol/g). With increasing the temperature of the thermal treatment up to 550 °C, the amorphous Nb2O5 was gradually transformed into a pseudohexagonal phase, resulting in a decrease in surface area (27–39 m2/g) and total acidity (0.05–0.19 mmol/g). The catalysts’ performance in cascade dehydration of glucose realized in pure water was strongly influenced by the total acidity of these materials. A remarkable yield of 37% HMF in one-pot reaction in water was achieved using mesoporous amorphous niobium oxide prepared by thermal treatment of niobic acid at 300 °C in air. The best-performing catalyst displayed a total acidity lower than niobic acid (1.69 mmol/g) which afforded a correct balance between a high glucose conversion and limited further conversion of the target product to numerous polymers and humins. On the other hand, the treatment of niobic acid at 550 °C, independently of the atmosphere used during the sample preparation (i.e., air or N2), resulted in Nb2O5 catalysts with a high ratio of Lewis to Brønsted acid sites and poor total acidity. These materials excelled at catalyzing the isomerization step in the tandem process.

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Section: Resultsmentioning

confidence: 99%

Impact of Thermal Treatment of Nb2O5 on Its Performance in Glucose Dehydration to 5-Hydroxymethylfurfural in Water

et al. 2020

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“…phenols subsequently diffuse onto the catalyst surface to undergo deoxygenation reactions. As shown in Figure 5, the deoxygenation of phenol to form benzene can proceed by three distinct pathways: the tautomerization-dehydration and tautomerization-decarbonylation routes starting from the cleavage of the O-H bond and a direct dehydration route via the breaking of the C aryl -OH bond (Lup et al, 2017;Rogers and Zheng, 2016;Teles et al, 2018). There are four generally accepted pathways for removing the methoxy group from guaiacol: (1) cleavage of the O-CH 3 bond to produce methane (demethylation) and catechol,…”

Section: Possible Reaction Pathways For the Catalytic Fast Pyrolysis mentioning

confidence: 99%

Controlling Deoxygenation Pathways in Catalytic Fast Pyrolysis of Biomass and Its Components by Using Metal-Oxide Nanocomposites

Zheng¹,

Huang²,

Wei

et al. 2020

iScience

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Selectively breaking the CO bonds within biomass during catalytic fast pyrolysis (CFP) is desired, but extremely challenging. Herein, we develop a series of metal-oxide nanocomposites composed of W, Mo, Zr, Ti, or Al. It is demonstrated that the nanocomposites of WO 3-TiO 2-Al 2 O 3 exhibit the highest deoxygenation ability during CFP of lignin, which can compete with the commercial HZSM-5 catalyst. The nanocomposites can selectively cleave the CO bonds within lignin-derived phenols to form aromatics by direct demethoxylation and subsequent dehydration. Moreover, the nanocomposites can also achieve the selective breaking of the CO bonds within xylan and cellulose to form furans by dehydration. The Brønsted and Lewis acid sites on the nanocomposites can be responsible for the deoxygenation of lignin and polysaccharides, respectively. This study provides new insights for the rational design of multifunctional catalysts that are capable of simultaneously breaking the CO bonds within lignin and polysaccharides.

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“…[22][23][24][25][26] Aromatic products can be formed on Pt, [27] especially on bifunctional Pt catalysts. [23,[28][29][30] Noronha, Resasco and co-workers [29,[31][32][33] have studied alkylphenol HDO with a bifunctional, niobia-supported palladium catalyst. Niobia, a reducible oxide, [34] is a promising support for bifunctional catalysts: [32,33,35] compared to Pd/SiO 2 , Pd/Nb 2 O 5 provided a 40-fold higher selectivity to benzene in phenol HDO.…”

Section: Introductionmentioning

confidence: 99%

“…[23,[28][29][30] Noronha, Resasco and co-workers [29,[31][32][33] have studied alkylphenol HDO with a bifunctional, niobia-supported palladium catalyst. Niobia, a reducible oxide, [34] is a promising support for bifunctional catalysts: [32,33,35] compared to Pd/SiO 2 , Pd/Nb 2 O 5 provided a 40-fold higher selectivity to benzene in phenol HDO. [32] A similar catalyst, multifunctional Pt/NbOPO 4 , has been used in the one-pot conversion of wood sawdust into hexane, pentane, and alkylcyclohexanes with yields up to 28.1 wt%.…”

Section: Introductionmentioning

confidence: 99%

“…Regarding the reaction medium in alkylphenol HDO, recent studies have focused on vapor-phase operation, and they often report high selectivities to aromatic hydrocarbons. [23,[31][32][33]37] However, HDO in liquid solvents might be beneficial for integration with liquefaction. Many studies on the HDO of phenolics with solvents have focused mostly on guaiacol, rather than on alkylphenols.…”

Section: Introductionmentioning

confidence: 99%

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Hydrodeoxygenation of Propylphenols on a Niobia‐Supported Platinum Catalyst: Ortho, Meta, Para Isomerism, Reaction Conditions, and Phase Equilibria

Escobedo

Mäkelä

Neuvonen

et al. 2020

Advanced Sustainable Systems

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managed responsibly. [2,3] Such renewable biofuels are especially promising for sustainable aviation. [4] The biopolymers that constitute lignocellulose can be broken down, among other means, by liquefaction. [5-7] Liquefaction relies on thermochemistry (200-400 °C) and on a liquid solvent, such as a high boiling point hydrocarbon. [6,7] The same solvent can be used in subsequent upgrading steps. The product of liquefaction is biocrude: a complex mixture of phenolics, furanics, cyclic ketones, carboxylic acids, and other compounds. [6] The high concentration of oxygenates renders biocrudes chemically unstable, poor in heating value, corrosive, highly viscous, and prone to form coke. [6,8] Hence, further upgrading is necessary, with a possible upgrading step being hydrodeoxygenation (HDO): a type of hydrotreatment, in which biocrude constituents react with dihydrogen on a heterogeneous catalyst, producing deoxygenated compounds and water. [8] Fittingly, HDO can proceed in the presence of an organic solvent. [7] Liquefaction biocrudes are highly unsaturated (60-65% carbon) and resemble lignin or pyrolysis liquids. [6] They are rich in phenolic compounds, and hence they are a potential source of bio-based aromatic hydrocarbons. Aromatic hydrocarbons are essential to the chemical industry, [9-12] and they are also required in fuels. [4] For example, international standards stipulate that jet fuel should contain 8% to 25% aromatics. [4,13,14] Although the abundant phenolics produced in liquefaction are suitable for conversion to aromatic hydrocarbons via HDO, the challenge, especially with alkylphenols, is that the aryl-hydroxyl bond is among the strongest in lignocellulose. [8] Furthermore, it is necessary to prevent the hydrogenation of the aromatic ring. Thus, in order to overcome these obstacles, it is pertinent to study the HDO of alkylphenols, for which catalyst development is essential. Many factors in the HDO process can influence the performance of a HDO catalyst. Some of these factors are the reaction medium, [15,16] the reaction temperature and pressure with their thermodynamic and kinetic effects, [17] and the ortho, meta, and para isomerism of alkylphenols. [18] Sulfided catalysts are considered conventional in commercial hydrotreatment. [19,20] Unfortunately, the activity of sulfided The alkylphenols found in liquefied lignocellulose could become a source of biobased aromatic hydrocarbons for fuel components. In the hydrodeoxygenation (HDO) of alkylphenols, hydroxyl groups must be removed while avoiding the hydrogenation of the aromatic ring. Here, the HDO of propylphenols is studied using a Pt/Nb 2 O 5 catalyst and n-tetradecane solvent. HDO experiments are performed using different reaction conditions of batch residence time (0-161 min g cat g reactant −1), pressure (20-30 bar H 2), and temperature (300-375 °C). HDO is studied with ortho-, meta-, and para-propylphenol. The influence of vapor-liquid equilibrium and chemical equilibrium are assessed using thermodynamic calculations. Almost full deoxygena...

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Catalytic upgrading of biomass pyrolysis vapors and model compounds using niobia supported Pd catalyst

Cited by 86 publications

References 48 publications

Impact of Thermal Treatment of Nb2O5 on Its Performance in Glucose Dehydration to 5-Hydroxymethylfurfural in Water

Impact of Thermal Treatment of Nb2O5 on Its Performance in Glucose Dehydration to 5-Hydroxymethylfurfural in Water

Controlling Deoxygenation Pathways in Catalytic Fast Pyrolysis of Biomass and Its Components by Using Metal-Oxide Nanocomposites

Hydrodeoxygenation of Propylphenols on a Niobia‐Supported Platinum Catalyst: Ortho, Meta, Para Isomerism, Reaction Conditions, and Phase Equilibria

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