Enhanced Concentration of Medium Strength Brönsted Acid Sites in Aluminium-Modified β Zeolite

Esquivel, Dolores; Cruz‐Cabeza, Aurora J.; Jiménez‐Sanchidrián, César; Romero–Salguero, Francisco J.

doi:10.1007/s10562-011-0736-6

Cited by 8 publications

(6 citation statements)

References 28 publications

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“…The XRD patterns of the metal exchanged zeolite β ( Figure 1 ) were almost identical to that of the protonic zeolite [ 22 ]. No diffraction lines corresponding to oxide crystallites were observed, thus indicating that metal cations were well dispersed on the zeolite.…”

Section: Resultsmentioning

confidence: 98%

“…The highest populations of Lewis sites were found for the samples exchanged with Co 2+ , Ni 2+ and Cu 2+ . The marked decrease in Lewis acidity for sample Al-β has been recently explained by the reduction of the octahedrally coordinated aluminium atoms [ 22 ]. Also, strong sites were absent in zeolite Pb-β, similar to alkaline-earth exchanged zeolite β [ 19 ].…”

Section: Resultsmentioning

confidence: 99%

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Metal-Exchanged β Zeolites as Catalysts for the Conversion of Acetone to Hydrocarbons

et al. 2012

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Various metal-β zeolites have been synthesized under similar ion-exchange conditions. During the exchange process, the nature and acid strength of the used cations modified the composition and textural properties as well as the Brönsted and Lewis acidity of the final materials. Zeolites exchanged with divalent cations showed a clear decrease of their surface Brönsted acidity and an increase of their Lewis acidity. All materials were active as catalysts for the transformation of acetone into hydrocarbons. Although the protonic zeolite was the most active in the acetone conversion (96.8% conversion), the metal-exchanged zeolites showed varied selectivities towards different products of the reaction. In particular, we found the Cu-β to have a considerable selectivity towards the production of isobutene from acetone (over 31% yield compared to 7.5% of the protonic zeolite). We propose different reactions mechanisms in order to explain the final product distributions.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Metal-Exchanged β Zeolites as Catalysts for the Conversion of Acetone to Hydrocarbons

et al. 2012

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“…Based on the peak areas, the amounts of the weak, strong, and total acids were quantitatively obtained (Table ). It was observed that the position of the desorption peak of the strong acid shifted to the low-temperature region after NaOH desilication; however, it shifted to a high-temperature region after mild treatment, employing the mixed acid. Combined with the structural characterization results, the tetrahedral-framework Al was inevitably removed during the alkali treatment, thereby weakening the strong-acid site .…”

Section: Resultsmentioning

confidence: 99%

Enhancing the Catalytic Properties of Mordenites via an Alkali–Acid Treatment and by Loading Nickel–Cerium during o-Ethyltoluene Isomerization

Cao

Wang

et al. 2021

ACS Omega

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The catalytic performance of the selective isomerization of oethyltoluene (O-ET) is crucial to increasing the m-ethyltoluene (M-ET) and pethyltoluene (P-ET) yields. During the isomerization of O-ET, traditional (commercial) mordenites (HM) are generally limited by a high reaction temperature (235 °C), as well as a low yield of the isomerization product (49.0%). In this study, micro-mesoporous mordenites were obtained by treating commercial mordenites with NaOH, NaOH−HNO 3 , and NaOH−mixed acid (HNO 3 −oxalic). Thereafter, their structure, porosity, and acidity were investigated via X-ray diffraction, transmission electron microscopy, inductively coupled plasma, N 2 sorption, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy of pyridine, temperature-programmed desorption of ammonia, and nuclear magnetic resonance. Among the various treated samples, the accessibility of the acidic sites and the B/L value of the alkali− mixed HNO 3 −oxalic one were enhanced, achieving the highest yield (53.6%) and lowest reaction temperature (165 °C), thus significantly reducing the energy consumption of the reaction process. Furthermore, Ni and Ce were successfully loaded via the incipient wetness impregnation of the micro-mesoporous mordenite to significantly prolong the catalytic life. This study affords a new strategy for obtaining high M-ET and P-ET yields from the isomerization of O-ET in mixed C 9 aromatics on an industrial scale.

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“…The desorption peaks in the ranges of 150-200 °C (T 1 ), 230-260 °C (T 2 ), and 430-470 °C (T 3 ) are attributed to weak, medium, and strong acid sites, respectively. 31 According to the literature, 32,33 medium and strong acid sites are collectively called strong acid sites. Based on the peak areas and total acid amounts, 32 the amounts of weak and strong acid sites were calculated (Table 3).…”

Section: Characterisation Of Catalystmentioning

confidence: 99%

Comparison of surface passivation modification of two mordenite zeolites and their application on the isomerisation of o-ethyltoluene

et al. 2022

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Enhanced Concentration of Medium Strength Brönsted Acid Sites in Aluminium-Modified β Zeolite

Cited by 8 publications

References 28 publications

Metal-Exchanged β Zeolites as Catalysts for the Conversion of Acetone to Hydrocarbons

Metal-Exchanged β Zeolites as Catalysts for the Conversion of Acetone to Hydrocarbons

Enhancing the Catalytic Properties of Mordenites via an Alkali–Acid Treatment and by Loading Nickel–Cerium during o-Ethyltoluene Isomerization

Comparison of surface passivation modification of two mordenite zeolites and their application on the isomerisation of o-ethyltoluene

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