Supported Keggin type heteropolycompounds for ecofriendly reactions

Pizzio, Luis R.; Vázquez, Patricia; Cáceres, Carmen Victoria; Blanco, Mirta N.

doi:10.1016/s0926-860x(03)00394-6

Cited by 253 publications

(123 citation statements)

References 34 publications

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“…42 TRMC measurements were carried out as previously described. 43 The incident microwaves were generated by a Gunn diode in the K a band (29)(30)(31). The experiments were performed at 30.0 GHz, frequency corresponding to the highest microwave power.…”

Section: Characterization Of the Solidsmentioning

confidence: 99%

“…Therefore, the spectra indicate that the The typical FTIR spectrum of the Keggin species was completely absent for the samples POM/Al 2 O 3 and POM/ZnO, indicating that the integrity of the POM system was strongly disturbed in agreement with previous studies. 23,28,29 This was attributed to an acid-base reaction between the acidic POM and the basic surface of these supports, as demonstrated by the PZC of the oxides. This strong interaction of POM with the basic metal-oxide support results in a decline of its acidity and the detrimental effect of such interactions on the catalytic activity of the binary material has been well documented.…”

mentioning

confidence: 94%

“…34 These strong interactions were attributed to the basicity of the support 28 and the detrimental effect of such interactions on the catalytic activity has also been well documented. [27][28][29] In a previous paper the catalytic and catalytic photo-assisted activity of the H 3 PW 12 O 40 POM supported on TiO 2 Evonik P25 and SiO 2 was studied and a beneficial role of the photocatalytically active support on the reaction rate was reported. 35 The contemporary presence of heat and UV light improved the activity of the POM supported materials for the propene hydration reaction and the catalytic photo-assisted reaction occurred at a higher rate than the catalytic one when the solid support was an irradiated semiconductor.…”

Section: Introductionmentioning

confidence: 99%

“…This strong interaction of POM with the basic metal-oxide support results in a decline of its acidity and the detrimental effect of such interactions on the catalytic activity of the binary material has been well documented. 23,28,29,61 It is worth noting that the analogous FTIR spectra of the POM supported materials after being used for 10 h in catalytic or catalytic photo-assisted reactions, not reported for the sake of brevity, showed no significant differences, in the range 1200-800 cm À1 , with respect to the fresh powders indicating that no modifications of the POM Keggin unit occurred after the reactivity. The point of zero charge (PZC) value of surfaces of the various supports can give an idea of the acidic-basic entity of the surface.…”

mentioning

confidence: 99%

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Keggin heteropolyacid H3PW12O40 supported on different oxides for catalytic and catalytic photo-assisted propene hydration

Marcı̀

García‐López

Bellardita

et al. 2013

Phys. Chem. Chem. Phys.

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Catalytic and catalytic photo-assisted hydration of propene to form 2-propanol in gas-solid regime at atmospheric pressure and 85 1C were carried out by using a heteropolyacid (POM) supported on different oxides. Binary materials were prepared by impregnation of H 3 PW 12 O 40 on different commercial and home prepared supports (TiO 2 , SiO 2 , WO 3 , ZrO 2 , ZnO, Al 2 O 3 ). Some of the composites were active both for catalytic and catalytic photo-assisted reactions. The Keggin type POM was completely and partially degraded, when supported on ZnO and Al 2 O 3 , respectively, and these binary solids always resulted as inactive for both catalytic and catalytic photo-assisted reactions. The supported Keggin POM species played a key role both for the catalytic and the photo-assisted catalytic reactions, due to their strong acidity and ability to form strong oxidant species under UV irradiation, respectively. The contemporary presence of heat and UV light improved the activity of almost all POM supported materials. All materials were characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM), diffuse reflectance spectroscopy (DRS), determination of the conduction and valence band energy by photovoltage measurements, Fourier transform infrared spectroscopy (FTIR), NH 3 -TPD experiments and time resolved microwave conductivity (TRMC).

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Section: Characterization Of the Solidsmentioning

confidence: 99%

mentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Keggin heteropolyacid H3PW12O40 supported on different oxides for catalytic and catalytic photo-assisted propene hydration

Marcı̀

García‐López

Bellardita

et al. 2013

Phys. Chem. Chem. Phys.

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“…The Ei indicates the maximum acid strength of the surface sites [53]. It can be observed that Ei increased with the amount of PW immobilized in SBA-15, which can be due to the increase in the amount of protons with PW loading of the SBA-15 support.…”

Section: Valorization Of Waste Cooking Oil Into Biodiesel Over Heteromentioning

confidence: 96%

Valorization of Waste Cooking Oil into Biodiesel over Heteropolyacids Immobilized on Mesoporous Silica — A Kinetic Study

Caiado¹,

Tropecêlo²,

Castanheiro³

2015

Biofuels - Status and Perspective

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A Kinetic Investigation of Triacetin Methanolysis and Assessment of the Stability of a Sulfated Zirconium Oxide Catalyst

Temoteo

Silva

Rodrigues

et al. 2018

J Americ Oil Chem Soc

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In this work, the activity and stability of a sulfated zirconium catalyst in transesterification reactions of triacetin, a model molecule, were investigated. This catalyst has Lewis and Brønsted acid sites and has shown to be highly active in reactions converting triacetin into methyl esters. This catalyst was synthesized using the impregnation method, and systematically characterized using the techniques of x‐rays diffraction (XRD), scanning electron microscopy, Fourier transform‐infrared spectroscopy (FT‐IR), Brunauer, Emmett, and Teller, and thermal gravimetry analysis (TGA). Kinetic studies were carried out to determine the activation energy as well as the reaction order. The effects of the main reaction parameters, such as temperature, the molar ratio, and the catalyst content, were evaluated. The reuse and possible leaching of the catalyst were also investigated. The highest efficiency (ca. 99% of methyl esters) was achieved in the sulfated zirconium oxide‐catalyzed transesterification reaction.

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Supported Keggin type heteropolycompounds for ecofriendly reactions

Cited by 253 publications

References 34 publications

Keggin heteropolyacid H3PW12O40 supported on different oxides for catalytic and catalytic photo-assisted propene hydration

Keggin heteropolyacid H3PW12O40 supported on different oxides for catalytic and catalytic photo-assisted propene hydration

Valorization of Waste Cooking Oil into Biodiesel over Heteropolyacids Immobilized on Mesoporous Silica — A Kinetic Study

A Kinetic Investigation of Triacetin Methanolysis and Assessment of the Stability of a Sulfated Zirconium Oxide Catalyst

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