Properties of modified aluminas

Jirátová, Květa; Beránek, L.

doi:10.1016/0166-9834(82)80196-6

Cited by 52 publications

(16 citation statements)

References 9 publications

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“…When the sodium content exceeds 1.0%, almost no NH 3 desorption at higher temperature appears. This result clearly indicates that sodium can neutralize the strong acidic sites of the catalysts effectively, which is consistent with the results of prior research [29,30].…”

Section: Catalysts Characterizationsupporting

confidence: 81%

Effect of Sodium Addition to PtSn/AlSBA-15 on the Catalytic Properties in Propane Dehydrogenation

et al. 2010

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The effect of Na addition to PtSn/AlSBA-15 on the catalytic properties in propane dehydrogenation was studied. The catalysts were characterized by XRF, BET, HR-TEM, NH 3 -TPD, TPO and TPR. Results showed that the presence of sodium could not only modify the acid function of the catalysts but also the structure of metallic phase, thus reduce the amount of coke deposition. Among the catalysts investigated, PtSnNa (1.0%)/AlSBA-15 had the best catalytic performance in terms of propane conversion and stability. The high catalytic performance may be owing to the strong interaction between metal and support.

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Section: Catalysts Characterizationsupporting

confidence: 81%

Effect of Sodium Addition to PtSn/AlSBA-15 on the Catalytic Properties in Propane Dehydrogenation

et al. 2010

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“…Thus, Pines and Haag [8] found that alkali metal ions poison the Lewis acidic sites of the alumina. Jiratová and Beranek [9] reported a selective poisoning of the support when alumina is doped with Na ions. García Cortez et al [10] and Bocanegra et al [11], found that Li, Na and K ions poison the acidic sites of alumina.…”

Section: Introductionmentioning

confidence: 99%

Characterization and Catalytic Performance of PtSn Catalysts Supported on Al2O3 and Na-doped Al2O3 in n-butane Dehydrogenation

et al. 2007

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PtSn/Al 2 O 3 and PtSn/Al 2 O 3 -Na catalysts display important modifications of the metallic phase with respect to Pt/Al 2 O 3 one. In this sense, TPR and XPS results show the presence of strong interactions between Pt and Sn, with probable alloy formation, which would be responsible for the decrease of the reaction rate and the increase of the activation energy in cyclohexane dehydrogenation. Besides the experiments of cyclopentane hydrogenolysis show that the alkali metal addition to bimetallic PtSn/Al 2 O 3 catalysts completely eliminates the hydrogenolytic ensembles, which could be due to a geometric modification of the metallic phase. These important modifications in the nature of the metallic function due to the simultaneous addition of Na and Sn to Pt/Al 2 O 3 are responsible for the excellent catalytic performance in the n-butane dehydrogenation, thus giving high conversions, selectivities to butenes higher than 95%, and lower deactivation capacity than those corresponding to bimetallic PtSn catalysts (with different Sn contents) supported on undoped alumina. The excellent stability of PtSn/Al 2 O 3 -Na catalysts would be due to a low carbon formation during the reaction, such as it was observed from pulse experiments.

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“…In this way, a great e!ort has been carried out for controlling the crystalline structure of the alumina (4,6), as well as its surface properties; for example, by changing the synthesis conditions (7). These properties can vary with the alumina hydration degree or the impurities incorporated into its crystalline structure.…”

Section: Introductionmentioning

confidence: 99%