Manganese-containing MCM-41 for epoxidation of styrene and stilbene

Zhang, Qinghong; Wang, Ye; Itsuki, Satoko; Shishido, Tetsuya; Takehira, Katsuomi

doi:10.1016/s1381-1169(02)00323-0

Cited by 135 publications

(94 citation statements)

References 33 publications

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“…A serious leaching of V species was also observed at higher V-loading as compared to Mn, which was observed to be very stable in silica framework. This observation was in good agreement with Zhang et al [30] who investigated the epoxidation of styrene and stilbene in presence of V-and Mn-grafted MCM-41 taking TBHP as oxidant. Further work is needed to understand the mechanism of this epoxidation process.…”

Section: Epoxidation Of Cyclohexenesupporting

confidence: 92%

Enhanced Catalytic Activity of Ti, V, Mn-Grafted Silica Spheres Towards Epoxidation Reaction

Das

Parida

2008

Catal Lett

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A simple, cost effective and reusable transition metal (M = Ti, V, Mn)-grafted mesoporous silica spheres were synthesized by sol-gel technique and characterized by SXRD, FTIR, UV-Vis DRS, SEM, EDS, BET-surface area, pore volume and average pore diameter. Epoxidation of cyclohexene to cyclohexene oxide over these modified silica spheres using TBHP as oxidant was performed to compare the catalytic activities. Cyclohexene oxide selectivity was recorded to be 87.5% with 72.5% conversion over 8 wt% Ti-grafted silica spheres in comparison to V and Mn-grafted catalysts.

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Section: Epoxidation Of Cyclohexenesupporting

confidence: 92%

Enhanced Catalytic Activity of Ti, V, Mn-Grafted Silica Spheres Towards Epoxidation Reaction

Das

Parida

2008

Catal Lett

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“…Thus the band at 500 nm was assigned to Mn 2+ probably existing on the surface of MCM-41. These absorption maxima coincide with the reports in the literature [30]. From the above results, it is inferred that the Mn 2+ and Mn 3+ ions may be coordinated with Si(IV) by disordered octahedral and tetrahedral environments, respectively.…”

Section: Dr Uv-vis Spectroscopysupporting

confidence: 90%

A Comparative Study on the Catalytic Activity of Mn Containing MCM-41 Molecular Sieves for Oxidation of p-Cymene

Vetrivel

Pandurangan

2007

Catal Lett

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Mesoporous silica molecular sieves SiMCM-41, AlMCM-41 with Si/Al ratio equal to 158 and MnMCM-41 with Si/Mn ratio equal to 29 were synthesized by hydrothermal method. Manganese oxide impregnated on SiMCM-41 and on AlMCM-41 catalysts were also prepared by wet impregnation method. These catalysts referred as Mn/SiMCM-41 and Mn/AlMCM-41 (158). Both the manganese incorporated and impregnated catalysts structure was elucidated by XRD. Nitrogen adsorption isotherm was used to determine specific surface area, pore volume, and pore size distribution. The thermal stability of the as-synthesized catalyst was studied using TG-DTA. The presence of Mn 2+ was evident through DR UV-VIS and ESR spectroscopy. Through ESR studies, MnMCM-41 (29) was assigned to have framework Mn(II) sites. Extraframework manganese species with well-resolved sextet, centered at g = 2.00 had octahedral symmetry was observed in Mn/SiMCM-41 and Mn/AlMCM-41 (158). Mn retained its +2 oxidation state (ESR active) even upon calcination at 550°C in presence of air. The catalytic activity of the above-mentioned manganese containing MCM-41 catalysts were tested by vapor phase oxidation of p-cymene with CO 2 -free air in the temperature range from 200 to 400°C in steps of 50°C. The major products were 4-methylacetophenone (4-MAP), 4-isopropyl benzaldehyde (4-IPB), 1,2-epoxyisopropyl benzaldehyde or 1,2-epoxycumenaldehyde (1,2-ECA) and 4-methyl styrene (4-MS). Among the product selectivity, (4-MAP) was found to be higher than that of others. The order of the activity of catalysts followed Mn/SiMCM-41 [ Mn/AlMCM-41 (158) [ Mn/SiO 2 .

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“…It finds applications for the oxidation of -pinene by means of metals salts of Cu, Co, Mn and Pd 125 and for the manufacture of oxygenated terpenes. 126 Further examples include: cyclohexene oxidation to cyclohexane epoxide by Ru clusters, 127 epoxidation of styrene and stylbene from Mn supported on MCM-41, 128 asymmetric epoxidation of allylic alcohols by V centres. 129 When TBPH is used, the by-product of the reaction is tert-butyl alcohol (TB-OH), which can be recycled by subsequent reaction with H 2 O 2 in acid media.…”

Section: Oxygen Donors For Catalytic Oxygen Transfermentioning

confidence: 99%

Catalytic oxygen activation versus autoxidation for industrial applications: a physicochemical approach

Liu

Ryabenkova

Conte

2015

Phys. Chem. Chem. Phys.

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The activation and use of oxygen for the oxidation and functionalization of organic substrates is among the most important reactions in a chemist's toolbox. Nevertheless, despite the vast literature on catalytic oxidation, the phenomenon of autoxidation, an ever-present background reaction that occurs in virtually every oxidation process, is often neglected. In contrast, autoxidation can affect the selectivity to a desired product, to those dictated by pure freeradical chain pathways, thus affecting the activity of any catalyst used to carry out a reaction.This critical review compares catalytic oxidation routes by transition metals versus autoxidation, particularly focusing on the industrial context, where highly selective and "green" processes are needed. Furthermore, the application of useful tests to discriminate between different oxygen activation routes, especially in the area of hydrocarbon oxidation, with the aim of an enhanced catalyst design, is described and discussed. In fact, one of the major targets of selective oxidation is the use of molecular oxygen as ultimate oxidant, combined with the development of catalysts capable to perform the catalytic cycle in a real energy and cost effective manner on a large scale. To achieve this goal, insights from metallo-proteins that could find application in some areas of industrial catalysis are presented, as well as considering the physicochemical principles that are at the fundament of oxidation and autoxidation processes.3

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Manganese-containing MCM-41 for epoxidation of styrene and stilbene

Cited by 135 publications

References 33 publications

Enhanced Catalytic Activity of Ti, V, Mn-Grafted Silica Spheres Towards Epoxidation Reaction

Enhanced Catalytic Activity of Ti, V, Mn-Grafted Silica Spheres Towards Epoxidation Reaction

A Comparative Study on the Catalytic Activity of Mn Containing MCM-41 Molecular Sieves for Oxidation of p-Cymene

Catalytic oxygen activation versus autoxidation for industrial applications: a physicochemical approach

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