Carbon Promoted ZrO<sub>2</sub> Catalysts for Aqueous-Phase Ketonization of Acetic Acid

Wu, Kejing; Yang, Mei; Pu, Weihua; Wu, Youqing; Shi, Yanchun; Hu, Husheng

doi:10.1021/acssuschemeng.7b00226

Cited by 30 publications

(34 citation statements)

References 53 publications

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“…The main product is 3-pentanone, the selectivity of which is higher than 97.5% on the two catalysts ( Figure 4B), and the minor products include methylketene, propionic anhydride and propanal, in accordance with others' reports on ZrO 2 [25,26]. The surface-based intrinsic reaction rate of propionic acid is higher on t-ZrO 2 than that on m-ZrO 2 in the temperature range of 300-375 • C ( Figure 5), which is consistent with previous studies on acetic acid ketonization [28,31].…”

Section: Catalytic Performancesupporting

confidence: 92%

“…This may be due to the different reaction conditions (condensed phase and vapor phase) via the different reaction mechanisms or different metal oxides used.As the higher activity catalyst in the ketonization of carboxylic acid, ZrO 2 and the modified ZrO 2 catalysts have been studied using experimental measurements and density functional theory calculations (DFT) [28][29][30][31][32][33][34][35]. Wu et al performed acetic acid ketonizaion over carbon promoted ZrO 2 catalysts and on the Zr/Mn mixed oxides at 340 • C in the aqueous-phase ketonization [28,29]. They found that carbon promoted ZrO 2 with tetragonal phase was more active than that possessing monoclinic phase, and the different carbon species and carbon content resulted in different stability.…”

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confidence: 99%

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Effect of Zirconia Polymorph on Vapor-Phase Ketonization of Propionic Acid

Ding

Zhao

2019

Catalysts

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Vapor-phase ketonization of propionic acid derived from biomass was studied at 300-375 • C over ZrO 2 with different zirconia polymorph. The tetragonal ZrO 2 (t-ZrO 2 ) are more active than monoclinic ZrO 2 (m-ZrO 2 ). The results of characterizations from X-ray diffraction (XRD) and Raman suggest m-ZrO 2 and t-ZrO 2 are synthesized by the solvothermal method. NH 3 and CO 2 temperature-programmed desorption (NH 3 -TPD and CO 2 -TPD) measurements show that there were more medium-strength Lewis acid base sites with lower coordination exposed on m-ZrO 2 relative to t-ZrO 2 , increasing the adsorption strength of propionic acid. The in situ DRIFTS (Diffuse reflectance infrared Fourier transform spectroscopy) of adsorbed propionic acid under ketonization reaction reveal that as the most abundant surface intermediates, the monodentate propionates are more active than bidentate propionates. In comparison with m-ZrO 2 , the t-ZrO 2 surface favors monodentate adsorption over bidentate adsorption. Additionally, the adsorption strength of monodentate propionate is weaker on t-ZrO 2 . These differences in adsorption configuration and adsorption strength of propionic acid are affected by the zirconia structure. The higher surface concentration and weaker adsorption strength of monodentate propionates contribute to the higher ketonization rate in the steady state.Catalysts 2019, 9, 768 2 of 15 coordination of Ti 4+ cations exposed on the surface. Stubenrauch et al. studied the reaction of formic acid and acetic acid on CeO 2 (111) and (100) surface [24]. On both surfaces, CH 2 CO was produced through acetic acid dehydration near 600 K. However, acetone was detected only on the (111) surface during acetic acid decomposition at 600 K. This result is different from that obtained by Kim et al., since Ce 4+ cations of (111) surface possess one vacancy relative to the Ce 4+ cations in the bulk. Wang et al. carried out ketonization of carboxylic acid on anatase and rutile TiO 2 , monoclinic and tetragonal ZrO 2 at 503-533 K [25,26]. They showed that the reaction activity of acetic acid was higher over anatase TiO 2 than that over rutile TiO 2 , and attributed that to the more reactive monodentate acetate present on anatase TiO 2 , whereas unreactive bidentate acetate was present on rutile TiO 2 . The effect of different nanocrystals (nanocubes, nanorods and nanopolyhedra) of CeO 2 on acetic acid ketonization was studied by Snell et al. at 503 K in the condensed phase and at 623 K in the vapor phase [27]. They found that the crystal of CeO 2 was disrupted in the condensed phase with the formation of metal carboxylate, whereas the bulk structure was maintained during the vapor phase reaction. They suggested that the morphology of CeO 2 did not have a critical influence on the reaction activity in the condensed and vapor phase. Although some work has been done on the influence of the structure, no consensus has been reached. This may be due to the different reaction conditions (condensed phase and vapor phase) via the different reaction...

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Section: Catalytic Performancesupporting

confidence: 92%

mentioning

confidence: 99%

Effect of Zirconia Polymorph on Vapor-Phase Ketonization of Propionic Acid

Ding

Zhao

2019

Catalysts

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“…Although SZr has been extensively used in different organic transformations, as far as we know, only a few examples of carbon supported Zr and SZr have been recently reported . Among them, Zr‐supported on carbon nanotubes has been reported for the ketonization of acetic acid . In this sense, we tested the carbon supported Zr and SZr in the reaction under study.…”

Section: Resultssupporting

confidence: 91%

“…[26][27][28] Among them, Zr-supported on carbon nanotubes has been reported for the ketonization of acetic acid. [29] In this sense, we tested the carbon supported Zr and SZr in the reaction under study. As can be observed from Figure 7, conversion values of 2 were up to 80 %, after the first 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 15 min of reaction time, when operating in the presence of the N catalysts.…”

Section: Resultsmentioning

confidence: 99%

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Enhanced Catalytic Properties of Carbon supported Zirconia and Sulfated Zirconia for the Green Synthesis of Benzodiazepines

et al. 2018

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This work reports for the first time a new series of promising porous catalytic carbon materials, functionalized with Lewis and Brønsted acid sites useful in the green synthesis of 2,3‐dihydro‐1H‐1,5‐benzodiazepine – nitrogen heterocyclic compounds. Benzodiazepines and derivatives are fine chemicals exhibiting interesting therapeutic properties. Carbon materials have been barely investigated in the synthesis of this type of compounds. Two commercial carbon materials were selected exhibiting different textural properties: i) Norit RX3 (N) as microporous sample and ii) mesoporous xerogel (X), both used as supports of ZrO2 (Zr) and ZrO2/SO42− (SZr). The supported SZr led to higher conversion values and selectivities to the target benzodiazepine. Both chemical and textural properties influenced significantly the catalytic performance. Particularly relevant are the results concerning the non‐sulfated samples, NZr and XZr, that were able to catalyze the reaction leading to the target benzodiazepine with high selectivity (up to 80 %; 2 h). These results indicated an important role of the carbon own surface functional groups, avoiding the use of H2SO4. Even very low amounts of SZr supported on carbon reveal high activity and selectivity. Therefore, the carbon materials herein reported can be considered an efficient and sustainable alternative bifunctional catalysts for the benzodiazepine synthesis.

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