Transformation of anisole over ZnAl2O4 and Fe2O3/ZnAl2O4 catalysts

Grabowska, Hanna; Zawadzki, M.; Syper, Ludwik

doi:10.1016/j.apcata.2004.01.021

Cited by 21 publications

(3 citation statements)

References 33 publications

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“…Each method resulted in materials with different surface areas. For comparison purposes, ZnAl 2 O 4 surface area values of 17.3, 86, 99 and 58 m 2 g −1 were obtained by combustion, co‐precipitation, hydrothermal and sol‐gel techniques (respectively), whereas CuAl 2 O 4 surface area values found in the literature were of 10, 41 and 87 (respectively) for sol‐gel, modified sol‐gel and microwave combustion techniques. Therefore, the results revealed that the route presented in this work generates materials with a high surface area by a technically easier and simpler method, without the need for sophisticated procedures such as microwave or expensive precursors …”

Section: Resultsmentioning

confidence: 99%

Reactive oxygen species‐induced heterogeneous photocatalytic degradation of organic pollutant Rhodamine B by copper and zinc aluminate spinels

Vieira

Leichtweis

Foletto

et al. 2019

J of Chemical Tech & Biotech

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BACKGROUND: The importance of potable water is immeasurable and its contamination by pollutants is a serious environmental problem. Rhodamine B (RhB), one such pollutant, is highly toxic to various organisms and may cause long-term undesirable effects when improperly disposed of. Thus, development of an efficient treatment technique is necessary. Among the new oxidation methods, heterogeneous photocatalysis is an emerging pollutant destructive technology. RESULTS: The photocatalytic activities of copper (Cu) and zinc (Zn) aluminate spinels (CuAl 2 O 4 and ZnAl 2 O 4 ) was evaluated.Chemical and physical properties were considered, and ZnAl 2 O 4 showed higher RhB degradation efficiency (73.90% in only 10 min) than CuAl 2 O 4 (51.95% in 10 min), reaching up to 100% in 30 min. According to results, a further RhB catalytic degradation pathway by ZnAl 2 O 4 was monitored by UV-visible spectrometry and ultra-high performance liquid chromatography coupled to diode array detection (UHPLC-DAD) analysis. When applied to wastewater from gemstone beneficiation, containing elevated RhB concentration, the ZnAl 2 O 4 caused 88% color removal in 120 min and its pollutant removal rate was 18 times greater than the commonly used ZnO.CONCLUSION: The superior performance of ZnAl 2 O 4 can be attributed to better pore properties, responsible for providing more active sites. These identified reactive oxygen species (ROS)-induced interactions and the species demonstrated that degradation occurs due to generation of O 2•and h + . Thus, ZnAl 2 O 4 proved to be an efficient photocatalyst for quick RhB pollutant degradation with promising potential for real wastewater treatment applications. CONCLUSIONBoth Cu and Zn aluminate spinels presented elevated catalytic performance, but when compared, ZnAl 2 O 4 presented higher J Chem Technol Biotechnol 2020; 95: 791-797

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Section: Resultsmentioning

confidence: 99%

Reactive oxygen species‐induced heterogeneous photocatalytic degradation of organic pollutant Rhodamine B by copper and zinc aluminate spinels

Vieira

Leichtweis

Foletto

et al. 2019

J of Chemical Tech & Biotech

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“…The formation of 2,6-xylenol can be explained by the disproportionation reaction between two ortho-cresol molecules [Equation (4)]. [22] The high selectivity towards phenol can be interpreted by considering the adsorption of anisole, a weak Lewis base, onto the acidic Al 2 O 3 sites. This makes the anisole prone to nucleophilic attack.…”

Section: Resultsmentioning

confidence: 99%

Reductive Dealkylation of Anisole and Phenetole: Towards Practical Lignin Conversion

2011

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We present and develop alternative catalysts for biomass conversion and specifically lignin conversion into aromatics. Unlike the conventional CoMo and NiMo formulations, our catalysts can convert low-sulfur feedstocks. A set of five magnesia–alumina mixed oxides were screened in the hydrodealkylation of alkyl phenyl ethers as lignin model compounds. The typical selectivity to phenol is 30–75 %. Interestingly, we saw that the more basic the catalyst, the higher the selectivity for phenol. The results concur with the formation of phenoxide (PhO–) and RH3+ fragments on the catalyst surface. These can then react with H+ and H– species formed by the hydrogen dissociation on the MgO surface, giving phenol and hydrocarbons. We conclude that magnesia–alumina mixed oxides are attractive candidates for catalyzing lignin breakdown. These catalysts are highly stable, inexpensive, and readily available.

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“…[2] For the impregnated materials, it is possible to notice a reduction in the intensity of the bands related to the Brønsted acid sites and an increase in the intensity of the bands concerning the Lewis acid sites. This occurs because the ZnAl 2 O 4 material has the presence of only Lewis sites [46] which increases in quantity when incorporated into pure solid H-BEA, especially when a high spinel content is added, which results in a considerable reduction of the B/L ratio, as shown in Table 1.…”

Section: Acidic Propertiesmentioning

confidence: 99%

Glycerol Conversion into Allyl Alcohol Using a Coke‐tolerant ZnAl₂O₄‐β Zeolite Catalyst: Effect of Structural, Textural, and Acidic Properties on Catalytic Stability

et al. 2023

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Catalysts with different ZnAl 2 O 4 contents impregnated in beta zeolite were synthesized and their catalytic activity in glycerol dehydration to allyl alcohol was investigated. The materials were characterized by XRD, XRF, FTIR, DRIFTS-pyridine, NH 3 -TPD, and N 2 physisorption. In addition, the surface electrostatic potential maps were generated by a molecular mechanics approach. The XRD patterns indicated a high dispersion of the ZnAl 2 O 4 , evidenced by the absence of reflections in the diffractograms, except for the sample containing the highest spinel content. The FTIR spectra indicated the presence of zinc aluminate spinel in the zeolite matrix. The DRIFTS-pyridine and NH 3 -TPD analyses indicated that the incorporation of ZnAl 2 O 4 modifies the acidic properties of the zeolite concerning the number, type, and distribution of acid sites. The N 2 physisorption tests showed the maintenance of the micro and mesoporous properties of H-BEA after modification, despite the reduction of the specific area and pore volume values. The samples impregnated with the ZnAl 2 O 4 phase showed larger mesopores sizes, which may favor its catalytic performance. The catalytic tests indicated the allyl alcohol production for the impregnated materials, which the best results were obtained by the sample containing 2 % of ZnAl 2 O 4 , with 90.65 % glycerol conversion and 37 % allyl alcohol selectivity due to appropriate tuning of the acidic and textural properties, as well as the presence of basic sites evidenced by CO 2 -TPD analysis and electrostatic potential maps. The presence of acid-base sites is essential to conduct hydrogen transfer, according to the proposed mechanism, generating allyl alcohol. Finally, the results with a longer reaction period showed greater stability for the sample impregnated with low spinel content, whose coke deposition was smaller, which may be related to the larger size of secondary mesopores.

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Transformation of anisole over ZnAl2O4 and Fe2O3/ZnAl2O4 catalysts

Cited by 21 publications

References 33 publications

Reactive oxygen species‐induced heterogeneous photocatalytic degradation of organic pollutant Rhodamine B by copper and zinc aluminate spinels

Reactive oxygen species‐induced heterogeneous photocatalytic degradation of organic pollutant Rhodamine B by copper and zinc aluminate spinels

Reductive Dealkylation of Anisole and Phenetole: Towards Practical Lignin Conversion

Glycerol Conversion into Allyl Alcohol Using a Coke‐tolerant ZnAl₂O₄‐β Zeolite Catalyst: Effect of Structural, Textural, and Acidic Properties on Catalytic Stability

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Transformation of anisole over ZnAl2O4 and Fe2O3/ZnAl2O4 catalysts

Cited by 21 publications

References 33 publications

Reactive oxygen species‐induced heterogeneous photocatalytic degradation of organic pollutant Rhodamine B by copper and zinc aluminate spinels

Reactive oxygen species‐induced heterogeneous photocatalytic degradation of organic pollutant Rhodamine B by copper and zinc aluminate spinels

Reductive Dealkylation of Anisole and Phenetole: Towards Practical Lignin Conversion

Glycerol Conversion into Allyl Alcohol Using a Coke‐tolerant ZnAl2O4‐β Zeolite Catalyst: Effect of Structural, Textural, and Acidic Properties on Catalytic Stability

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Product

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About

Glycerol Conversion into Allyl Alcohol Using a Coke‐tolerant ZnAl₂O₄‐β Zeolite Catalyst: Effect of Structural, Textural, and Acidic Properties on Catalytic Stability