Catalytic properties of antimony-SBA-15 materials in the benzylation of aromatics reactions

Bachari, K.; Touileb, A.; Cherifi, O.

doi:10.1134/s0023158409030112

Cited by 6 publications

(6 citation statements)

References 32 publications

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“… [a] Ageing temperature; [b] Final zirconium loading measured by using ICP–OES, with incorporation efficiency in parentheses; [c] Total pore volume; [d] Micropore volume; [e] “Accessible” pore volume; [f] Pore size calculated as the maximum of pore size distribution calculated by using the BJH method using a nitrogen multilayer thickness curve specifically obtained for SBA‐15 materials;47 [g] Surface area calculated from the BET method; [h] Micropore surface area; [i] “Accessible” surface area for mesopores/macropores; [j] Interplanar spacing calculated as d 100 =( d 100 +√3⋅ d 110 +√4⋅ d 200 )/3; [k] The p 6 mm lattice parameter a =2⋅ d 100 /√3; [l] Wall thickness; [m] Acid loading calculated from NH 3 TPD profiles; [n] Maximum temperature of the NH 3 desorption profile; [o] Active surface area calculated from H + by using 0.14 nm 2 molecule −1 for the average cross‐sectional area of NH 3 ; [p] Accessibility of supported acid zirconium species, calculated as the specific number of acid sites per zirconium content. …”

Section: Resultsmentioning

confidence: 99%

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Maximizing the Accessibility of Active Species in Weakly Acidic Zr‐SBA‐15 Materials

et al. 2012

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Weakly acidic Zr‐SBA‐15 materials were synthesized by using a novel method to maximize the accessibility of zirconium sites in view of their catalytic applications. Synthesized materials at different ageing temperatures were characterized by means of several techniques such as XRD, N2 physisorption, TEM, ammonia temperature‐programmed desorption, and X‐ray photoelectron spectroscopy and subsequently used in a test acid‐catalyzed process such as the microwave‐assisted alkylation of anisole with benzyl chloride. Reaction results revealed the very high catalytic activity of the prepared Zr‐SBA‐15 materials, which depended mostly on the accessibility of the supported zirconium species and their speciation.

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Section: Resultsmentioning

confidence: 99%

“…The alkylation of aromatics with benzyl chloride has been reported to be primarily catalyzed by Lewis acid sites 46. 47 The results are summarized in Table 2 and illustrated in Figure 6. The reaction proceeded smoothly for all materials in a short reaction time (typically 5 min).…”

Section: Resultsmentioning

confidence: 99%

Maximizing the Accessibility of Active Species in Weakly Acidic Zr‐SBA‐15 Materials

et al. 2012

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“…H2SO4, HCl, HNO3) are most frequently used in the synthesis of benzylated arenes, 8 however, they cause sever environmental issues and problems with catalyst separation and regeneration. 9 Environmentally friendly heterogeneous catalysts have been developed to replace homogeneous acids, including zeolites and mesoporous silica-alumina, 7,[10][11][12][13][14][15][16][17][18][19][20][21][22] acidic oxides and sulphides, [23][24][25][26][27][28][29][30] and heteropoly acids (HPAs). 15,31 Zeolites, having crystalline framework, high surface area, regular porous structure, and strong acidity, are the most popular catalysts used in current chemical processes.…”

Section: ◼ Introductionmentioning

confidence: 99%

Catalytic arene alkylation over H-Beta zeolite: Influence of zeolite shape selectivity and reactant nucleophilicity

Zeng

Wang

Ding

et al. 2019

Journal of Catalysis

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Renewable arenes and aromatic alcohols can be derived from lignocellulose by biorefineries, which has been considered as a sustainable alternative to replace petrochemical feedstocks in the synthesis of monobenzylation products, key industrial intermediates, via benzylation reactions. Zeolites with micropores are the most widely used catalysts in the benzylation of arenes, however, their performance suffers from diffusion limitations in converting large arenes. In this work, mesoporous and microporous H-Beta zeolites were prepared and applied in the systematic study of benzylation of arenes (benzene, toluene, p-xylene and mesitylene) with benzyl alcohol (BA). The porous structure of these zeolites has been confirmed by XRD, BET and TEM techniques. The catalytically active Brønsted acid sites (BAS) were determined by quantitative 1 H magic-angle spinning (MAS) nuclear magnetic resonance (NMR) experiments. The benzylation studies have shown that introducing mesopores into H-Beta zeolites can significantly increase the diffusion/access of arenes to surface sites, particularly for bulky arenes (e.g. mesitylene), while micropores are mainly selective for the conversion of small arenes (e.g. benzene).Increasing the nucleophilicity of arenes with more alkyl groups can enhance their catalytic performance in mesopores, however, the increase hinders their conversion in micropores because of the shape selectivity due to their increasing molecular size. Compared to mesopores, micropores promote the conversion of small arenes (e.g. benzene), which can be additionally enhanced by a high Brønsted acidity. Therefore, introducing a suitable porosity balanced with acidity is are keys in the tailoring of the catalytic performance of H zeolites for target benzylation reactions.

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“…Three probable mechanistic interpretations can be found in the literature for benzylation of aromatic hydrocarbons with benzyl chloride on solid acid based supported metal catalysts, without any direct (preparative or spectroscopic) experimental verification: a simple radical step [12][13][14][15][16][17] -see Scheme 1; the presence of a benzyl chloride radical cation [4,[18][19][20][21][22][23][24][25]] -see Scheme 2; or the presence of a benzyl radical cation [26][27][28] as intermediate -see Scheme 3. In some cases the same authors have different suggestions for similar catalytic systems.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic Evidence for the Involvement of a Radical Intermediate in the Friedel-Crafts Benzylation Using Ion-Exchanged K10 Catalysts

Hell

Korecz

Békássy

2018

Period. Polytech. Chem. Eng.

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For Friedel-Crafts alkylation of aromatic hydrocarbons an ionic reaction path is considered as classical reaction mechanism. The alkylation with benzyl chloride in the presence of ion-exchanged K10 montmorillonite catalysts containing multivalent, reducible cations had an outstanding activity, therefore a radical initial step as a supplement to the ionic mechanism was proposed earlier. We made ESR investigations to clarify the existence and the nature of the suggested radical species. The ESR experiments verified that the reaction involves a radical step.

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Catalytic properties of antimony-SBA-15 materials in the benzylation of aromatics reactions

Cited by 6 publications

References 32 publications

Maximizing the Accessibility of Active Species in Weakly Acidic Zr‐SBA‐15 Materials

Maximizing the Accessibility of Active Species in Weakly Acidic Zr‐SBA‐15 Materials

Catalytic arene alkylation over H-Beta zeolite: Influence of zeolite shape selectivity and reactant nucleophilicity

Spectroscopic Evidence for the Involvement of a Radical Intermediate in the Friedel-Crafts Benzylation Using Ion-Exchanged K10 Catalysts

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