Liquid-Phase Oxidation of 2,6-Di-tert-butylphenol with Cu-Impregnated MCM-41 Catalysts in the Presence of Alkali Metals

Fujiyama, Hirofumi; Kohara, Ichitaro; Iwai, Koji; Nishiyama, Satoru; Tsuruya, Shigeru; Masai, Mitsuo

doi:10.1006/jcat.1999.2667

Cited by 41 publications

(18 citation statements)

References 23 publications

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“…zeolite, demonstrating advantages of mesoporous materials for oxidation of the bulky DTBP molecule [107,108].…”

Section: Coppermentioning

confidence: 99%

“…Although the catalytic activity was rather low (TOF = 0.4 h -1 ), the catalyst could be readily recovered and reused.Copper (II) was introduced into mesostructured silicates of the MCM-41 type having a hexagonal arrangement of mesopores-channels with uniform diameter of ca. 3.5 nm by impregnation[107] or ion exchange[108] procedures. The Cu(II)-impregnated and Cu(II)-ionexchanged MCM-41 materials showed activity in the liquid-phase oxidation of DTBP with molecular oxygen[107,108].…”

mentioning

confidence: 99%

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Recent advances in transition-metal-catalyzed selective oxidation of substituted phenols and methoxyarenes with environmentally benign oxidants

Kholdeeva

Zalomaeva

2016

Coordination Chemistry Reviews

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“…zeolite, demonstrating advantages of mesoporous materials for oxidation of the bulky DTBP molecule [107,108].…”

Section: Coppermentioning

confidence: 99%

mentioning

confidence: 99%

Recent advances in transition-metal-catalyzed selective oxidation of substituted phenols and methoxyarenes with environmentally benign oxidants

Kholdeeva

Zalomaeva

2016

Coordination Chemistry Reviews

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“…The oxidation reaction of DTBP carried out under different condition led to DTBQ and PQ mixture (table 4). In general, during the oxidation with the complex CuL, PQ appeared to be predominant product, similarly to the reaction catalysed by Cu(II) ions-amine systems [12,13,[15][16][17][18][19][25][26][27]. for Cu(II) uptake resulted in a greater yield of PQ than DTBQ.…”

Section: Resultsmentioning

confidence: 98%

“…Japanese authors [15,16] reported that liquid-phase catalytic oxidation of DTBP was performed on Cu ionexchanged Na MCM-41 support. They found that in a basic medium or in the presence of alkali metal, DTBP was easy deprotonated to phenolate anion.…”

Section: Introductionmentioning

confidence: 99%

Oxidation of 2,6-di-tert-butylphenols to Diphenoquinones Catalysed by Schiff Base-Cu(II) Systems Immobilized on Polymer Support

2006

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Benzoquinone, diphenoquinones and its derivatives are important intermediates for industrial synthesis of a wide variety of special chemicals, such as pharmaceuticals, dyes and agricultural chemicals. The useful catalyst were obtained by aminolysis of vinylbenzyl chloride/divinylbenzene copolymer with ethylenediamine (1) or urotropine (2) and then modification by salicylaldehyde (1A, 2A) or picolinaldehyde (1B, 2B). The catalytic activity of Cu(II) complexes with Schiff base immobilized on the synthesized supports were tested in the oxidation reaction of 2,6-di-tert-butylphenol (DTBP) to diphenoquinone (PQ) with tertbutylhydroperoxide. The best oxidation degree of DTBP (60-70%) and the selectivity towards PQ (80%) is revealed by Cu(II) complexes with long Schiff base ligands derived from salicylaldimine (1A), which have CuL structure (EPR measurement).

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“…A certain amount of Si-MCM-41, prepared by the solgel method as described elsewhere, 12 was dispersed in 0.1 M aqueous (NH 4 ) 2 TiF 6 solution for various durations (148 h) at 30°C. The structure and deposition behavior were investigated with transmission electron microscopy (TEM), X-ray diffraction (XRD), N 2 adsorption/desorption isotherms, and inductively coupled plasma atomic emission spectroscopy (ICP-AES).…”

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confidence: 99%

Surface Modification of Porous Silica with the Liquid Phase Deposition Process Using Solid Materials for Fluorine Scavenger

2012

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TiO 2 -modified silica-based MCM-41 (Si-MCM-41) was prepared by liquid phase deposition (LPD) without a conventional fluorine scavenger such as H 3 BO 3 . TiO 2 was deposited on Si-MCM-41 by LPD reactions for 148 h. Using Si-MCM-41, TiO 2 was deposited on the inner surface of silica with etching phenomena. After the LPD reactions, Si species were detected in the reaction solution as a result of etching phenomena of silica. It was confirmed that Si-MCM-41 also acted as a fluorine scavenger by dissolving and forming hexafluorosilicate in aqueous hexafluorotitanate solution. The deposition behavior was greatly influenced by the volume of the reaction solution. The photocatalytic activity of the modified Si-MCM-41 was much higher than that of conventional catalysts such as TiO 2 :P25.Porous materials are currently a major field of investigation for power-storage 1 and catalytic substances 2 because they provide large areas for these reactions. Metal oxides have a variety of functions such as electrical transport, magnetism, and optical responses. When these metal oxides can be prepared with porous structures, their functions are expected to be enhanced compared with those of nonporous materials, for the above reasons.TiO 2 itself has wide range of functions; in particular, highly active TiO 2 -MCM-41 has been proposed for various applications such as photocatalysts and electrode materials, because they have functional surfaces. However, high crystallinity causes a lack of structural ordering of mesoporous materials.3,4 TiO 2 thin films can be prepared by the controlled hydrolysis equilibrium of titaniumfluoro complexes by adding a fluorine scavenger, the so-called liquid phase deposition (LPD) process, 3 on various kinds of nanomaterials. In previous reports, various fluorine scavengers such as H 3 BO 3 and Fe(NO 3 ) 3 have been investigated.58 When such fluorine scavengers are used, the deposition species will infiltrate voids, and this is known as the liquid phase infiltration (LPI) process. In this study, we prepared TiO 2 -modified mesoporous silica Si-MCM-41 by the LPD method, without any conventional fluorine scavenger such as H 3 BO 3 . On-site (pore surface) synthesis of TiO 2 is expected when using solid materials as the fluorine scavenger. The stability of the fluoro complex is subject to the stability constant. When dipping the SiO 2 in the aqueous titaniumfluoro complex solution, since SiF 6 2¹ ions have large dissociation constants (pK d ca. 30), 10 TiF 6 2¹ is thought to be hydrolyzed to TiO 2 (pK d ca. 12).11 When choosing a solid-state scavenger, surface modification is expected and a large reaction field can be provided for the catalytic application. The reaction in this study is expressed by the following chemical reaction.Because MCM-41 has a well-defined structure and large specific surface area, we think that it can be used as a model case for surface modification on a highly structured material. While silica can have an arbitrary shape depending on its process, the surface is mostly inert for r...

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Liquid-Phase Oxidation of 2,6-Di-tert-butylphenol with Cu-Impregnated MCM-41 Catalysts in the Presence of Alkali Metals

Cited by 41 publications

References 23 publications

Recent advances in transition-metal-catalyzed selective oxidation of substituted phenols and methoxyarenes with environmentally benign oxidants

Recent advances in transition-metal-catalyzed selective oxidation of substituted phenols and methoxyarenes with environmentally benign oxidants

Oxidation of 2,6-di-tert-butylphenols to Diphenoquinones Catalysed by Schiff Base-Cu(II) Systems Immobilized on Polymer Support

Surface Modification of Porous Silica with the Liquid Phase Deposition Process Using Solid Materials for Fluorine Scavenger

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