One-step aldol condensation of ethyl acetate with formaldehyde over Ce and P modified cesium supported alumina catalyst

Sararuk, Chidchon; Yang, Dan; Zhang, Guoliang; Li, Chunshan; Zhang, Suojiang

doi:10.1016/j.jiec.2016.11.002

Cited by 29 publications

(6 citation statements)

References 37 publications

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“…From 323 K to about 513 K, the physically adsorbed water and small molecules are lost. From 513 K to about 833 K, the weight loss is mainly due to the combustion of deposited coke material . The weight losses of these two stages are 1.87% and 9.53%.…”

Section: Resultsmentioning

confidence: 99%

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Experimental and Theoretical Study for Vapor Phase Aldol Condensation of Methyl Acetate and Formaldehyde over Alkali Metal Oxides Supported on SBA-15

Wang

2018

Ind. Eng. Chem. Res.

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Alkali metal oxides supported on SBA-15, M/ SBA-15 (M = Li, Na, K, Rb, and Cs), prepared by the impregnation method were characterized and tested for the aldol condensation of methyl acetate and formaldehyde to methyl acrylate (MA). M/SBA-15 catalysts are active for the formation of MA while the support is inert. The supported alkali metals react with hydroxyl groups on SBA-15 by replacing the H atoms and generate weak and medium basic sites. The latter plays an important role in promoting the reaction. Coke formation results in deactivation of Cs/SBA-15, and the deactivated catalyst can be regenerated by burning off the coke. Two possible reaction pathways for the formation of MA were explored using quantum calculations. The predicated activity for M/SBA-15 is consistent with the experimental observations. A pathway with adsorbed enol molecule as an intermediate was suggested to be predominant for the formation of MA.

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Section: Resultsmentioning

confidence: 99%

“…From 513 K to about 833 K, the weight loss is mainly due to the combustion of deposited coke material. 47 The weight losses of these two stages are 1.87% and 9.53%.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 98%

Experimental and Theoretical Study for Vapor Phase Aldol Condensation of Methyl Acetate and Formaldehyde over Alkali Metal Oxides Supported on SBA-15

Wang

2018

Ind. Eng. Chem. Res.

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“…Quite unexpectedly, we found in this work that the cesium titanates Cs x Ti 2– x /4 □ x /4 O 4 ( x = 0.67 or 0.70; M = □; Cs x TO) and Cs x Ti 2– x /2 Zn x /2 O 4 ( x = 0.70; Cs 0.7 ZnTO), directly obtained right after solid state synthesis, were unusually acidic without the need for proton–ion exchange, pillaring, delamination, or restacking. These results provide an interesting example contrasting the general view that soft/polarizable cesium ions suppress acidic while promoting basic character. − Acidity and the acidic nature of the microcrystals of these compositions were evaluated by NH 3 and isopropylamine temperature-programmed desorption (TPD), Fourier transform infrared spectroscopy of adsorbed pyridine, and X-ray photoelectron spectroscopy (XPS). Effects of the Ti vacancy sites and activation temperature on acidity, including the stability of the cesium titanate, were also investigated.…”

Section: Introductionmentioning

confidence: 99%

An Unusually Acidic and Thermally Stable Cesium Titanate Cs_xTi_2–yM_yO₄ (x = 0.67 or 0.70; M = vacancy or Zn)

et al. 2019

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Proton-free, alkali-containing layered metal oxides are thermally stable compared to their protonic counterparts, potentially allowing catalysis by Lewis acid sites at elevated temperatures. However, the Lewis acidic nature of these materials has not been well explored, as alkali ions are generally considered to promote basic but to suppress acidic character. Here, we report a rare example of an unusually acidic cesium-containing oxide Cs x Ti 2−y M y O 4 (x = 0.67 or 0.70; M = Ti vacancy □ or Zn). These lepidocrocitetype microcrystals desorbed NH 3 at >400 °C with a total acidity of ≲410 μmol g −1 at a specific surface area of only 5 m 2 g −1 , without the need for lengthy proton−ion exchange, pillaring, delamination, or restacking. The soft and easily polarized Cs + ion essentially drives the formation of the Lewis acidic site on the surfaces as suggested by IR of sorbed pyridine. The twodimensional layered structure was preserved after the oxide was employed in the ethanol conversion at 380 °C, the temperature at which the protonic form could have converted to anatase. The structure was also retained after the NH 3 temperatureprogrammed desorption measurement up to 700 °C. The production of ethylene from ethanol, well-known to occur over acid sites, unambiguously confirmed the acidic nature of this cesium titanate.

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“…Yan et al 30 found that the mean pore diameters of Cs/SBA-15 catalysts increase from 7.22 to 8.27 nm with Cs content increasing from 0 to 20%. Sararuk et al 31 reported that the catalyst surface areas and pore volumes decreased but pore size increased with increasing Cs and P contents and interpreted it as being caused by pore blockage. It is important to note that catalyst channel characteristics, especially surface area, change significantly in the first 10 min of the initial adsorption stage, but the changes gradually weakened with the adsorption time.…”

Section: Catalyst Characterizationmentioning

confidence: 99%

Gradient Concentration Control of Active Components on the Industrial Cs-P/γ-Al₂O₃ Catalyst

Ran

Deng

Zhang

et al. 2022

Ind. Eng. Chem. Res.

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For supported catalysts, it is particularly important to ensure the effective loading of the active component on the support. A new industrial Cs-P/γ-Al2O3 catalyst with controllable distribution of active components was developed and applied to the aldol condensation reaction of methyl propionate and formaldehyde. The distribution of active components was controlled by adjusting the preparation conditions, especially the adsorption time, to form the catalyst with a gradient concentration of active components, which had been confirmed by the EMPA and SEM-EDS characterization. In addition, the kinetic equations including pseudo-first- and pseudo-second-order kinetic models as well as isotherm equations based on Freundlich and Langmuir models were used to describe the adsorption process to provide valuable process parameters for industrial production of catalysts.

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One-step aldol condensation of ethyl acetate with formaldehyde over Ce and P modified cesium supported alumina catalyst

Cited by 29 publications

References 37 publications

Experimental and Theoretical Study for Vapor Phase Aldol Condensation of Methyl Acetate and Formaldehyde over Alkali Metal Oxides Supported on SBA-15

Experimental and Theoretical Study for Vapor Phase Aldol Condensation of Methyl Acetate and Formaldehyde over Alkali Metal Oxides Supported on SBA-15

An Unusually Acidic and Thermally Stable Cesium Titanate Cs_xTi_2–yM_yO₄ (x = 0.67 or 0.70; M = vacancy or Zn)

Gradient Concentration Control of Active Components on the Industrial Cs-P/γ-Al₂O₃ Catalyst

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One-step aldol condensation of ethyl acetate with formaldehyde over Ce and P modified cesium supported alumina catalyst

Cited by 29 publications

References 37 publications

Experimental and Theoretical Study for Vapor Phase Aldol Condensation of Methyl Acetate and Formaldehyde over Alkali Metal Oxides Supported on SBA-15

Experimental and Theoretical Study for Vapor Phase Aldol Condensation of Methyl Acetate and Formaldehyde over Alkali Metal Oxides Supported on SBA-15

An Unusually Acidic and Thermally Stable Cesium Titanate CsxTi2–yMyO4 (x = 0.67 or 0.70; M = vacancy or Zn)

Gradient Concentration Control of Active Components on the Industrial Cs-P/γ-Al2O3 Catalyst

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An Unusually Acidic and Thermally Stable Cesium Titanate Cs_xTi_2–yM_yO₄ (x = 0.67 or 0.70; M = vacancy or Zn)

Gradient Concentration Control of Active Components on the Industrial Cs-P/γ-Al₂O₃ Catalyst