Effects of zeolite structure and composition on the synthesis of dimethyl carbonate by oxidative carbonylation of methanol on Cu-exchanged Y, ZSM-5, and Mordenite

Zhang, Yihua; Briggs, Daniel N.; Smit, Emiel de; Bell, Alexis T.

doi:10.1016/j.jcat.2007.07.018

Cited by 72 publications

(41 citation statements)

References 27 publications

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“…Comparing this behavior with NMR spectra (Figure ) suggests that group (1) corresponds to methoxy species bonded to the zeolite, while group (2) is associated with molecularly adsorbed methanol. This attribution is in line with literature data, showing a blue shift of the C−H stretching vibrations in methoxy species with respect to molecular methanol . The band at 2159 cm −1 of group (3) is typical of carbon monoxide adsorbed over Cu I and formed by thermal decomposition of formate, as revealed by NMR (Figure and Figure ).…”

Section: Resultssupporting

confidence: 91%

Pathways of Methane Transformation over Copper‐Exchanged Mordenite as Revealed by In Situ NMR and IR Spectroscopy

2019

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The reaction of methane with copper‐exchanged mordenite with two different Si/Al ratios was studied by means of in situ NMR and infrared spectroscopies. The detection of NMR signals was shown to be possible with high sensitivity and resolution, despite the presence of a considerable number of paramagnetic CuII species. Several types of surface‐bonded compounds were found after reaction, namely molecular methanol, methoxy species, dimethyl ether, mono‐ and bidentate formates, CuI monocarbonyl as well as carbon monoxide and dioxide, which were present in the gas phase. The relative fractions of these species are strongly influenced by the reaction temperature and the structure of the copper sites and is governed by the Si/Al ratio. While methoxy species bonded to Brønsted acid sites, dimethyl ether and bidentate formate species are the main products over copper‐exchange mordenite with a Si/Al ratio of 6; molecular methanol and monodentate formate species were observed mainly over the material with a Si/Al ratio of 46. These observations are important for understanding the methane partial oxidation mechanism and for the rational design of the active materials for this reaction.

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Section: Resultssupporting

confidence: 91%

Pathways of Methane Transformation over Copper‐Exchanged Mordenite as Revealed by In Situ NMR and IR Spectroscopy

2019

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“…The CuMOR structure (the chemical composition of the unit cell is Cu 2 Al 2 Si 46 O 97 ) has been considered because it allows formation of the centers, probably, of the CuOCu type, which oxidize CH 4 and is involved in the carbonylation with a moderate yield, while the carbonylation is the target for the next step calculations. The carbonate formation from CO 2 and H 2 O has been considered in NaX model (the chemical composition of the unit cell is Na 24 Al 24 Si 24 O 96 ).…”

Section: Computational Detailsmentioning

confidence: 99%

Carbonates in zeolites: Formation, properties, reactivity

Rybakov

Bryukhanov

Larin

et al. 2015

Int. J. Quantum Chem.

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Two possible schemes of carbonate formation (with and without water participation) in cationic form zeolites are considered. Activation energy for the formation of hydrogen carbonate in NaX zeolite from water and carbon dioxide is calculated at the DFT level with periodic boundary conditions, while the problems of modeling the formation of symmetric carbonate in the same zeolite are discussed. The formation of copper carbonate is studied using binuclear CuOCu clusters from CO 2 where the influence of water on the barrier is discussed. The questions related to DFT application to binuclear copper clusters are also considered by comparison with the data obtained at the MP2 level. The reactivity of copper carbonate is tested in the reaction with methanol.

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“…For the rst method of direct introduction of Cu(I), both vapor phase ion exchange (VPIE) and solid state ion exchange (SSIE) have been employed. [19][20][21][22] In addition to high temperatures, the harmful byproduct HCl is usually formed in the direct introduction of Cu(I). [13][14][15] This interesting method can achieve high Cu(I) loading, while high preparation temperatures (ca.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature fabrication of Cu(i) sites in zeolites by using a vapor-induced reduction strategy

et al. 2015

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Due to their versatility, nontoxicity, and low cost, Cu(I) ion exchanged zeolites are of great interest for various applications. Despite many attempts, the development of an efficient, controllable, and energysaving approach to fabricate Cu(I) sites in zeolites remains an open question. In this study, a strategy was developed to convert Cu(II) in zeolites to Cu(I) selectively using vapor-induced reduction (VIR) with methanol. The methanol vapors generated at elevated temperatures diffuse into the pores of zeolites and interact with Cu(II) ions, leading to the formation of Cu(I). This strategy allows the construction of Cu(I) sites at low temperatures and avoids the formation of Cu(0). Moreover, the obtained material exhibits excellent performance in the adsorptive separation of propylene/propane with regard to both capacity and selectivity, which is obviously superior to the material prepared by the conventional autoreduction method as well as using various typical adsorbents.

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Effects of zeolite structure and composition on the synthesis of dimethyl carbonate by oxidative carbonylation of methanol on Cu-exchanged Y, ZSM-5, and Mordenite

Cited by 72 publications

References 27 publications

Pathways of Methane Transformation over Copper‐Exchanged Mordenite as Revealed by In Situ NMR and IR Spectroscopy

Pathways of Methane Transformation over Copper‐Exchanged Mordenite as Revealed by In Situ NMR and IR Spectroscopy

Carbonates in zeolites: Formation, properties, reactivity

Low-temperature fabrication of Cu(i) sites in zeolites by using a vapor-induced reduction strategy

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