A transmission infrared spectroscopic investigation of the reaction of dimethyl ether with alumina surfaces

Chen, J. G.; Basu, Pallabita; Ballinger, Todd H.; Yates, John T.

doi:10.1021/la00086a011

Cited by 39 publications

(24 citation statements)

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“…The desorption of benzene occurred below 450 K. The fact that the peak temperatures for DME and its decomposition products were not affected by benzene may indicate that there are no interaction between DME and benzene in the adsorbed layer. This is confirmed by FTIR spectroscopic studies, which showed only the absorption bands belonging to undissociated DME, methoxy and methyl species [27,31,32], which were not affected by benzene. On ZSM-5(280) we measured much less amounts of DME, alkenes and n-butane desorbed.…”

Section: Tpd and Ftir Measurementssupporting

confidence: 58%

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Dimethyl Ether as a Source of Reactive Species for Alkylation of Benzene

Széchenyi

Solymosi

2008

Catal Lett

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The co-reaction of dimethyl ether and benzene has been investigated on pure and promoted-ZSM-5 catalysts at 473-773 K. It was found that the addition of benzene to dimethyl ether markedly increased the formation of toluene, xylene and C 9 aromatics on ZSM-5 at and above 623 K. This feature is attributed to the reaction of benzene with the reactive hydrocarbon species formed in the decomposition of dimethyl ether on the acidic sites of ZSM-5 zeolite. The extent of the enhancement was further increased by ZnO and Mo 2 C promoters.

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Section: Tpd and Ftir Measurementssupporting

confidence: 58%

“…are formed [27,31,32], the reaction of which may lead to the formation of C-C bond. Besides, the hydrocarbon-pool mechanism has also gained increasing acceptance [16,39].…”

Section: Catalytic Studiesmentioning

confidence: 99%

Dimethyl Ether as a Source of Reactive Species for Alkylation of Benzene

Széchenyi

Solymosi

2008

Catal Lett

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“…Studies of adsorption of dimethyl ether (DME) on an Al 2 O 3 film under UHV conditions found no dissociation of the ether [13]. But in studies on high surface area Al 2 O 3 containing hydroxyls, the DME is observed to dissociate [14]. Arai et al [15] studied the adsorption of diethyl ether (DEE) on high surface area alumina catalysts by infrared spectroscopy .…”

Section: Introductionmentioning

confidence: 99%

Structure and Reactivity of Alkyl Ethers Adsorbed on CeO2(111) Model Catalysts

et al. 2011

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The effect of surface hydroxyls on the adsorption of ether on ceria was explored. Adsorption of dimethyl ether (DME) and diethyl ether (DEE) on oxidized and reduced CeO 2 (111) films was studied and compared with Ru(0001) using RAIRS and sXPS within a UHV environment. On Ru(0001) the ethers adsorb weakly with the molecular plane close to parallel to the surface plane. On the ceria films, the adsorption of the ethers was stronger than on the metal surface, presumably due to stronger interaction of the ether oxygen lone pair electrons with a cerium cation. This interaction causes the ethers to tilt away from the surface plane compared to the Ru(0001) surface. No pronounced differences were found between oxidized (CeO 2 ) and reduced (CeOx) films. The adsorption of the ethers was found to be perturbed by the presence of OH groups on hydroxylated CeOx. In the case of DEE, the geometry of adsorption resembles that found on Ru, and in the case of dimethyl ether DME is in between that one found on clean CeOx and the metal surface. Decomposition of the DEE was observed on the OH/CeOx surface following high DEE exposure at 300 K and higher temperatures. Ethoxides and acetates were identified as adsorbed species on the surface by means of RAIRS and ethoxides and formates by s-XPS. No decomposition of dimethyl ether was observed on the OH/CeOx at these higher temperatures, implying that the dissociation of the C-O bond from ethers requires the presence of b-hydrogen.

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“…The bands in region A can in more detail be assigned to the C-H vibrations of formates and methoxy species, except for the band at 2928 cm -1 as seen from Table 3. According to Chen et al [26], molecularly adsorbed DME exhibits a clear band at 2922 cm -1 , which diminishes and shifts to 2962 cm -1 Scheme 1 Graphical illustration of species occurring during different conditions on an Al 2 O 3 surface during DME-SCR at 350°C in the presence of gas phase reactions [41,42] when adsorbed DME transforms to methoxy groups. Taking into account that the band at 2928 cm -1 is most pronounced when DME is present in the feed gas mixture and when no gas phase reactions occur ( Fig.…”

Section: Assignments Of Ir Absorption Bandsmentioning

confidence: 99%