Aldol condensation of furfural with acetone over Ca/ZSM-5 catalyst with lower dosages of water and acetone

Fang, Xiaowei; Wang, Ze; Song, Wenli; Li, Songgeng

doi:10.1016/j.jtice.2020.01.004

Cited by 11 publications

(5 citation statements)

References 25 publications

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“…Table S6 † compares the results for SiNb42 to literature data for different silica based solid catalysts tested for the target reaction. 41,42,[43][44][45]60,73,[76][77][78][80][81][82] Fair, clear comparisons are difficult to establish due to the different reaction conditions used in the different studies, and sometimes catalytic stability tests were not reported. Hence, this section is not intended to rank catalysts, but instead to give a summarized overview.…”

Section: Resultsmentioning

confidence: 99%

“…60 Besides catalytic activity and product yields, the stability of the catalysts is important from a practical point of view. The SiNb x type materials were stable whereas, for example, Ca-ZSM-5 (entry 12), 81 1.1 K-N-BEA (entry 13) 81 and 20K 2 O/12wt% MgAl-SBA-15 (entry 19) 82 suffered relatively rapid deactivation, 80 and, on the other hand, no catalytic stability tests were reported for MCM-22 (entry 11). 45…”

Section: Resultsmentioning

confidence: 99%

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Chemical valorisation of biomass derived furanics and carboxylic acids over niobium-based catalysts

Antunes,

Skrodczky,

Cabanelas

et al. 2024

Green Chem.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Chemical valorisation of biomass derived furanics and carboxylic acids over niobium-based catalysts

Antunes,

Skrodczky,

Cabanelas

et al. 2024

Green Chem.

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“…Several experimental studies have been performed to study aldol condensation of acetone inside zeolites, − however, computational efforts have been limited to a handful of studies. − For example, Migues et al have performed DFT calculations to obtain the barriers for aldol condensation of acetone with furfural in H-ZSM5. We are not aware of any previous computational work on keto–enol tautomerization of acetone in BEA zeolite.…”

Section: Introductionmentioning

confidence: 99%

Rate-Enhancing Role of Water in H-BEA and Sn-BEA for Keto–Enol Tautomerization of Acetone: A DFT Study

Goyal,

Agarwal

2023

J. Phys. Chem. C

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Aldol condensation of furfural with acetone is an important biofuel upgrading reaction. Herein, we investigated the rate-controlling step of aldol condensation, i.e., the keto−enol tautomerization of acetone, in Sn-doped BEA (Sn-BEA) and hydrogen-compensated Al-doped BEA (H-BEA) zeolites. We also investigated the rate-enhancing role of molecular water at 373 K. In dehydrated H-BEA, we find that the reaction takes place concertedly with a free-energy barrier, which is ∼160 kJ/mol lower than the uncatalyzed gas-phase reaction. The barrier is further reduced in the presence of water, which provides an alternate path for proton transfer. Further, we find that defect-free Sn-BEA under dehydrated conditions is catalytically inactive for the tautomerization of acetone. In the presence of H 2 O, we modeled two different active sites: monohydrated closed Sn-site and an open Sn-site formed by partial hydrolysis of a closed Sn-site. We find that a monohydrated closed Sn-site is thermodynamically more stable than an open Sn-site. Our calculations suggest that both configurations have comparable activity toward keto−enol tautomerization of acetone and are much higher than a dehydrated closed Sn-site. Overall, our calculations suggest that the activity of BEA zeolite is enhanced in the presence of low concentrations of water, which acts as a cocatalyst. This is true for both Sn-doped and Al-doped BEA, and the effect is more dramatic in the Sn-doped BEA.

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“… 28 Bifunctional heterogeneous catalysts (Mg–Al and Mg–Zr) on zeolite and hydrotalcite supports in particular have also shown high promise and are reported to have a high selectivity (86%) for the C 8 cross aldol product. 33 , 34 However, rapid catalyst deactivation as a result of coking is a major issue.…”

Section: Introductionmentioning

confidence: 99%

“…Both homogeneous basic catalysts, such as NaOH, , , and heterogeneous transition metal oxides composed of Zr, Pd, Mg, and Al have been widely used. − For the combination of acetone–furfural, a maximum selectivity of 90% has been reported for C 8 and C 13 products using a Mg–Al mixed oxide catalyst system . Bifunctional heterogeneous catalysts (Mg–Al and Mg–Zr) on zeolite and hydrotalcite supports in particular have also shown high promise and are reported to have a high selectivity (86%) for the C 8 cross aldol product. , However, rapid catalyst deactivation as a result of coking is a major issue.…”

Section: Introductionmentioning

confidence: 99%

Novel Route to Produce Hydrocarbons from Woody Biomass Using Molten Salts

et al. 2022

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The thermochemical decomposition of woody biomass has been widely identified as a promising route to produce renewable biofuels. More recently, the use of molten salts in combination with pyrolysis has gathered increased interest. The molten salts may act as a solvent, a heat transfer medium, and possibly also a catalyst. In this study, we report experimental studies on a process to convert woody biomass to a liquid hydrocarbon product with a very low oxygen content using molten salt pyrolysis (350–450 °C and atmospheric pressure) followed by subsequent catalytic conversions of the liquids obtained by pyrolysis. Pyrolysis of woody biomass in molten salt (ZnCl 2 /NaCl/KCl with a molar composition of 60:20:20) resulted in a liquid yield of 46 wt % at a temperature of 450 °C and a molten salt/biomass ratio of 10:1 (mass). The liquids are highly enriched in furfural (13 wt %) and acetic acid (14 wt %). To reduce complexity and experimental issues related to the production of sufficient amounts of pyrolysis oils for further catalytic upgrading, model studies were performed to convert both compounds to hydrocarbons using a three-step catalytic approach, viz., (i) ketonization of acetic acid to acetone, (ii) cross-aldol condensation between acetone and furfural to C 8 –C 13 products, followed by (iii) a two-stage catalytic hydrotreatment of the latter to liquid hydrocarbons. Ketonization of acetic acid to acetone was studied in a continuous setup over a ceria–zirconia-based catalyst at 250 °C. The catalyst showed no signs of deactivation over a period of 230 h while also achieving high selectivity toward acetone. Furfural was shown to have a negative effect on the catalyst performance, and as such, a separation step is required after pyrolysis to obtain an acetic-acid-enriched fraction. The cross-aldol condensation reaction between acetone and furfural was studied in a batch using a commercial Mg/Al hydrotalcite as the catalyst. Furfural was quantitatively converted with over 90% molar selectivity toward condensed products with a carbon number between C 8 and C 13 . The two-stage hydrotreatment of the condensed product consisted of a stabilization step using a Ni-based Picula catalyst and a further deep hydrotreatment over a NiMo catalyst, in both batch setups. The final product with a residual 1.5 wt % O is rich in (cyclo)alkanes and aromatic hydrocarbons. The overall carbon yield for the four-step approach, from pinewood biomass to middle distillates, is 21%, assuming that separation of furfural and acetic acid after the pyrolysis step can be performed without losses.

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Aldol condensation of furfural with acetone over Ca/ZSM-5 catalyst with lower dosages of water and acetone

Cited by 11 publications

References 25 publications

Chemical valorisation of biomass derived furanics and carboxylic acids over niobium-based catalysts

Chemical valorisation of biomass derived furanics and carboxylic acids over niobium-based catalysts

Rate-Enhancing Role of Water in H-BEA and Sn-BEA for Keto–Enol Tautomerization of Acetone: A DFT Study

Novel Route to Produce Hydrocarbons from Woody Biomass Using Molten Salts

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