Spectroscopic characterization of iron nanoparticles in Fe-mesoporous silicate catalysts

Bachari, K.; Millet, J.M.M.; Bonville, P.; Cherifi, O.; Figuéras, F.

doi:10.1016/j.jcat.2007.03.028

Cited by 50 publications

(32 citation statements)

References 23 publications

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“…Addition of the alcohol during the course of the reaction with tert-butylchloride virtually stopped the alkylation, indicating that oxygenated compounds act as poisons of the active sites. A similar situation was reported 16,17 to explain the preferential adsorption of benzyl ether and benzyl alcohol over clay catalysts, impairing the conversion of benzyl chloride in the Friedel-Crafts alkylation of toluene Recently, it was reported 15 that the presence of water leads to significant drop in the benzylation of benzene catalyzed by iron mesoporous molecular sieve. In fact, it has been reported that other Lewis acid catalysts 18 are also affected by the presence of water in the reaction medium.…”

Section: Effect Of Oxygenated Compoundssupporting

confidence: 64%

“…Bachari et al 15 found no correlation of the rate of benzylation of toluene, over iron mesoporous molecular sieve, with σ or σ + constants. In fact, they showed that there exists some correlation with the ionization potential of the aromatic substrate, interpreting these results in terms of one electron transfer mechanism.…”

Section: Effect Of Oxygenated Compoundsmentioning

confidence: 99%

“…Bachari et al 15 have recently revisited the mechanism of benzylation over iron-exchanged materials. They found no correlation between the rate of the reaction with several substituted benzene derivatives and the σ + constant.…”

Section: Introductionmentioning

confidence: 99%

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Mechanistic aspects of Friedel-Crafts alkylation over FeY zeolite

Bidart¹,

Borges²,

Chagas³

et al. 2006

J. Braz. Chem. Soc.

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Foram estudados os efeitos da razão molar aromático/cloreto de alquila, adição de base, solvente e agente alquilante, na alquilação do etilbenzeno catalisada pela zeólita FeY. Ficou caracterizada a alquilação ocorrendo no interior dos poros da zeólita, uma vez que ela é pouco afetada pela razão molar dos reagentes. A adição de bases e solventes oxigenados, capazes de complexar com o sítio ativo, inibe a reação. Foi proposto um mecanismo envolvendo transferência de um elétron entre as espécies de ferro ativas e o cloreto de alquila, para explicar os resultados.The effect of aromatic/alkylchloride molar ratio, base addition, solvent and alkylating agent on the ethylbenzene alkylation over FeY zeolite was investigated. It was shown that alkylation occurs inside the pores and it is little affected by the reactants molar ratio. On the other hand, addition of bases or oxygenated compounds, capable of complexing with the active site, blocks the reaction. A mechanism involving single electron transfer between the active iron species and the alkylchloride was propose to account for the results.

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Section: Effect Of Oxygenated Compoundssupporting

confidence: 64%

Section: Effect Of Oxygenated Compoundsmentioning

confidence: 99%

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Mechanistic aspects of Friedel-Crafts alkylation over FeY zeolite

Bidart¹,

Borges²,

Chagas³

et al. 2006

J. Braz. Chem. Soc.

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“…As shown in Fig. 3, the thermal variation of f p (T) shows two "plateaux", which means that the size distribution is bimodal, with two maxima [7]. Assuming K = 10 5 ergs/cm 3 , which is a typical value for ferric oxides, one can reproduce the thermal variation of f p (T) by varying the weights of the two distributions.…”

Section: Size Of the Ferrihydrite Nanoparticlesmentioning

confidence: 92%

57Fe Mössbauer study of a deposit in an industrial cooling circuit supplied with raw river water

Horner¹,

Herbelin²,

Goudot³

et al. 2010

Hyperfine Interact

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In this work, the nature of the deposit found inside an industrial cooling circuit (which consists of a mixture of different iron containing phases) has been characterized in detail by 57 Fe Mössbauer spectroscopy. Electron Paramagnetic Resonance spectroscopy was also used to check for the presence of other metals, mainly manganese and copper, detected by the Inductive Coupled Plasma method. We conclude that the deposit contains a large amount of Fe(III), probably consisiting of ferrihydrite nanoparticles and of goethite, either bulk or as large particles. It also contains traces of an Fe(II) species (about 3%), probably adsorbed on the iron oxides. Mn(II) and traces of Cu(II) are also present.

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“…[1 -3] The new environmental legislation pushes for the replacement of all liquid acids by solid acid catalysts which are environmentally more friendly catalysts and which lead to minimal pollution and waste. [4,5] Indeed, several solid acid catalysts have already been proposed which are efficient catalysts such as: Fe-modified ZSM-5 and H-β zeolites; Fe 2 O 3 or FeCl 3 deposited on micro-, meso-and macroporous [6] ; Fe-containing mesoporous molecular sieves materials [7,8] ; Fe-, Zn-, Ga-and In-modified ZSM-5 type zeolite catalysts [9] ; Ga-SBA-15 [10] ; InCl 3 , GaCl 3 , FeCl 3 and ZnCl 2 supported on clays and Si-MCM-41 [11] ; transition metal chloride-supported mesoporous SBA-15 [12] ; Sb supporting K10 [13] ; solid superacid and silica-supported polytrifluoro-methanesulfosil oxane [14] ; H 2 SO 4 , HNO 3 and HClO 4 /metakaolinite [15] ; alkali metal salts and ammonium salts of keggin-type heteropolyacids [16] ; ionexchanged clays [17] ; clayzic [18] ; solid superacids based on sulfated ZrO 2 [19] ; HY [20] ; Fe, Ce, W-modified Hβ zeolites [21] ; H-ZSM-5 [22] and FeCl 3 , MnCl 2 , CoCl 2 , NiCl 2 , CuCl 2 , ZnCl 2 supported on acidic alumina [23] for the benzylation of benzene and other aromatic compounds. However, the reports on the use of basic catalysts for the benzylation reactions are scarce.…”

Section: Introductionmentioning

confidence: 99%

Mg‐Fe‐hydrotalcite as catalyst for the benzylation of benzene and other aromatics by benzyl chloride reactions

Tahir

Abdelssadek

Halliche

et al. 2008

Surface & Interface Analysis

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The benzylation of benzene and substituted benzenes reaction employing benzyl chloride as the alkylating agent over Mg-Fe-LDH (Mg/Fe = 2) clay without or with calcination (at 473-1073 K) has been investigated. Hydrotalcite before and after its calcination was characterized for surface area and crystalline phases. The catalyst derived from the hydrotalcite by its calcination at 473-1073 K show high catalytic activity for the benzylation of benzene and other aromatic compounds. The catalytically active species present in the catalyst in its most active form are the oxides of iron on the catalyst surface. The activity of the catalyst calcined at 1073 K for the benzylation of different aromatic compounds is in the following order: benzene> toluene> p-xylene> anisole. Kinetics of the benzene benzylation over these catalysts have also been investigated. Copyright

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Spectroscopic characterization of iron nanoparticles in Fe-mesoporous silicate catalysts

Cited by 50 publications

References 23 publications

Mechanistic aspects of Friedel-Crafts alkylation over FeY zeolite

Mechanistic aspects of Friedel-Crafts alkylation over FeY zeolite

57Fe Mössbauer study of a deposit in an industrial cooling circuit supplied with raw river water

Mg‐Fe‐hydrotalcite as catalyst for the benzylation of benzene and other aromatics by benzyl chloride reactions

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