Boron - An Acidity and Texture Modifier for Alumina Supported Catalysts

Engels, S.; Herold, E.; Lausch, H.; Mayr, Hermann O.; Meiners, H.-W.; Wilde, M.

doi:10.1016/s0167-2991(08)64354-2

Cited by 7 publications

(5 citation statements)

References 5 publications

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“…For the boron modified adsorbent, despite the decrease in the specific surface area values, an increase in the pore diameter values was observed. This behavior can be due to the formation of new pores in the γ-Al 2 O 3 by the incorporation of boron or for the obstruction of pores with minor diameter, which was also observed by Engelso et al [37] when studying the boron incorporation on alumina. These authors suggest that with boron incorporation, the diameters of pores < 10 nm will be diminished, and new pores > 50 nm will appear.…”

Section: Resultssupporting

confidence: 58%

Simultaneous Adsorption of 4,6-Dimethyldibenzothiophene and Quinoline over Nickel and Boron Modified Gamma-Al2O3 Adsorbent

et al. 2020

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The simultaneous adsorption of quinoline and 4,6-dimethyldibenzothiophene over adsorbents, based on alumina modified with boron and nickel under ambient temperature and pressure, was studied. The adsorbents were characterized by BET specific surface area, a potentiometric method for the determination of acid strength, electrophoretic migration, and X-ray diffraction. The results showed that the adsorbent containing nickel had better adsorption capacity than the adsorbent modified with nickel and boron, which was attributed to its greater acidity and ability to generate π-complexation between the adsorbent and the molecules. In terms of selectivity, quinoline was more adsorbed than 4,6-dimethyldibenzothiophene in all systems, due to the basic nature of quinoline. The experimental data in all cases were adjusted by three kinetic models (Yoon–Nelson, Yan and Thomas), and the regression coefficients in all models were close to one. Finally, the values of the kinetic constant obtained by the Thomas model were used to relate the adsorption capacity results.

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Section: Resultssupporting

confidence: 58%

Simultaneous Adsorption of 4,6-Dimethyldibenzothiophene and Quinoline over Nickel and Boron Modified Gamma-Al2O3 Adsorbent

et al. 2020

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“…A binary oxide system, Al 2 O 3 /B 2 O 3 , has been applied in many reactions based on the use of heterogeneous catalysts. Thanks to its acidity, this system can be used in the reactions of Beckmann rearrangement [4][5][6][7][8][9][10], alcohol dehydration [11][12][13][14], partial oxidation of olefins [15][16][17][18][19], cracking [20][21][22][23], isomerization of hydrocarbons [24,25] and toluene disproportionation [25,26]. On the other hand, this system proved to be an effective support of metallic phase active in a number of reactions important for industry, like in the reactions of metathesis where it was a support of rhenium [27,28], cyclohexene hydrogenation, where it was a support of platinum [29] or carbon oxide hydrogenation as a support of ruthenium [30].…”

Section: Introductionmentioning

confidence: 99%

Highly dispersed Pt on B2O3/Al2O3 support: catalytic properties in the total oxidation of 1-butene

Przekop

Kirszensztejn

2016

Reac Kinet Mech Cat

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Applying a newly proposed method for the synthesis of a binary system Al 2 O 3 /B 2 O 3 , a series of metal phase supports with the ratio of B:Al components varied in the range from 0.05 to 1 was obtained. The supports were loaded with a metal phase from the water solution of H 2 PtCl 6 to get the final load of 1 % of the metallic phase. The samples were subjected to thermal treatment under oxidizing or reducing conditions. The degree of dispersion of the metal phase, evaluated on the basis of hydrogen chemisorption, was very high, reaching a maximum of over 150 %. The catalytic performance of the catalysts was tested in the reaction of temperature-programmed complete oxidation of 1-butene.

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“…This is the case for reactions such as the Beckmann rearrangement of cyclohexanone, − the dehydration of alcohols such as methanol, 2-propanol, , or butanol, the partial oxidation of alcanes such as ethane − or propane, cracking reactions, − but-1-ene 22 and the m -xylene isomezation, , and finally toluene disproportionation. , Boria−alumina mixed oxides can also be used for supporting active phases (typically metals). For instance, boria−alumina-supported Re has been used for metathesis reactions, , supported Pt has been used for cyclohexene hydrogenation, n -heptane conversion, dehydrocyclization, and hydroconversion 29 of n -octane. Supported Ru has been used for CO hydrogenation .…”

Section: Introductionmentioning

confidence: 99%

Characterization of Boria−Alumina Mixed Oxides Prepared by a Sol−Gel Method. 1. NMR Characterization of the Xerogels

et al. 2005

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While boria-alumina mixed oxides have been widely used for various catalytic reactions, their structure has never been satisfactory elucidated and is still a matter of debates. The present paper deals with the elucidation of the structure of boria-alumina prepared by a sol-gel method with B/Al atomic ratio varying from 0.013 to 1.643. The powders were prepared by hydrolysis of aluminum tri-sec-butoxide in the presence of (NH 4 ) 2 B 4 O 7 ‚4H 2 O. Then, the solid-state magic angle spinning (MAS) NMR spectroscopy was used to characterize the obtained solids in the dried state (xerogels), the calcined state being the object of a next paper. Both 27 Al and 11 B MAS NMR spectra were recorded with subsequent simulation of these last ones. This allowed to build a consistent structural model of these xerogels, taking into account the evolutions of calculated parameters such as the quadrupolar interaction, the real chemical shift, and the relative quantity of, respectively, BO 3 , BO 4 , tetrahedral, pentahedral, and octahedral aluminum species as a function of the B/Al atomic ratio. As a result, it was found that, for B/Al < 0.06, presence of boron induces the creation of bulk and surface tetrahedral aluminum species. Then, for B/Al > 0.06, BO 3 chains attached to these tetrahedral aluminum species are formed and start to grow through the matrix. Further, for B/Al > 0.15, when the boron loading increases, the BO 3 chains progressively emerge outside of the matrix, crossing it over. Furthermore, for B/Al > 0.26, some pentahedral aluminum species are formed supposedly due to the considerable steric strains afforded by some particular aluminum atoms. In brief, the presented model elucidates the structure of the dried alumina-based xerogels and is the key starting point to explain the structure of the oxides obtained after calcination and presented in the following paper.

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Boron - An Acidity and Texture Modifier for Alumina Supported Catalysts

Cited by 7 publications

References 5 publications

Simultaneous Adsorption of 4,6-Dimethyldibenzothiophene and Quinoline over Nickel and Boron Modified Gamma-Al2O3 Adsorbent

Simultaneous Adsorption of 4,6-Dimethyldibenzothiophene and Quinoline over Nickel and Boron Modified Gamma-Al2O3 Adsorbent

Highly dispersed Pt on B2O3/Al2O3 support: catalytic properties in the total oxidation of 1-butene

Characterization of Boria−Alumina Mixed Oxides Prepared by a Sol−Gel Method. 1. NMR Characterization of the Xerogels

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