Hierarchical mesoporous ZSM-5 for the dehydration of methanol to dimethyl ether

Yang, Qi; Zhang, Haitao; Kong, Meng; Bao, Xiuxiu; Fei, Jinhua; Zheng, Xiaoming

doi:10.1016/s1872-2067(12)60621-4

Cited by 20 publications

(13 citation statements)

References 30 publications

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“…The catalyst synthesized with a 0% of CTAB showed the poorest catalytic activity (only 25 and 56% of methanol conversion at 200 and 220°C, respectively). These results differed from those published elsewhere reporting an excellent activity for pure ZSM‐5. However, ZSM‐5 showed a poor catalytic performance herein because it only contains a microporous ZSM‐5 structure.…”

Section: Resultscontrasting

confidence: 99%

Effect of the template on the hydrothermal synthesis of mixed molecular sieves for methanol dehydration

Zhang

2018

Env Prog and Sustain Energy

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In this work, microporous–mesoporous H‐ZSM‐5/MCM‐41 mixed molecular sieves catalyst was successfully synthesized using a hydrothermal synthesis technology. Mesoporous MCM‐41 sieves were obtained by partial alkali treatment of microporous H‐ZSM‐5. The effect of the amount of template (i.e., cetyltrimethyl ammonium bromide, CTAB) on the preparation process of catalyst was investigated. The catalyst was characterized using X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and N2 adsorption–desorption. Methanol dehydration to dimethyl ether was selected to evaluate the catalytic performance of H‐ZSM‐5/MCM‐41. The content of mesoporous MCM‐41 in the mixed molecular sieve catalyst as well as its particle and pore sizes increased with the amount of CTAB, thereby enhancing the catalytic activity of the final material while keeping constant the microporous ZSM‐5 loadings. Thus, the amount of mesoporous MCM‐41 in the mixed molecular sieve catalyst reached a maximum at a CTAB loading of 10%, with the resultant material showing a maximum specific surface area of 335 m2/g and a mean pore size of 3.8 nm. Additionally, this material showed optimum catalytic activity (84% methanol conversion at 220°C). © 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901–1907, 2018

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Section: Resultscontrasting

confidence: 99%

Effect of the template on the hydrothermal synthesis of mixed molecular sieves for methanol dehydration

Zhang

2018

Env Prog and Sustain Energy

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“…Several studies [21][22][23] reveal that surface acidity and catalyst structure control the product selectivity in MTD reaction. In the present study, the effect of the pretreatment variables (pH and Si/Al ratio) and posttreatment variable (steaming time) are assessed on the characterization and reactor results.…”

Section: Experimental Designmentioning

confidence: 99%

Adjusting acidity and porosity of Al‐SBA‐15 catalyst for methanol to dimethyl ether reaction

Kharaji

Beheshti

Tangestaninejad

et al. 2020

Asia-Pacific J Chem Eng

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The present study aims to conduct a systematic assessment of Al-SBA-15 as the aluminum-substituted mesoporous catalyst for raw methanol dehydration to dimethyl ether (MTD). The catalysts are synthesized by varying the pretreatment variables (pH of the preparation and Si/Al ratio), the posttreatment variable (steaming time), and by the addition of aluminophosphate as the binder. The experimental design and the analysis of the results, especially the relation of characterization results and reactor performance, are performed by the optimal response surface method in Design-Expert software. The prepared micro-mesoporous catalyst exhibits an excellent activity, stability, and DME selectivity; therefore, it can be introduced as an efficient catalyst for raw methanol dehydration.

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“…28 Nevertheless, to avoid this, the strength and surface density of acid sites can be varied to a certain extent in order to improve the zeolite's catalytic properties. 17 Different technical solutions were proposed in this aim: partial neutralization of strong acid sites with alkaline metals, 16,31 H-ZSM-5 binding in a matrix of alumina (which is diluting the density of strong acid centers), 16 reducing the acidity by increasing the Si/Al ratio, 24,33,34 decreasing the zeolite crystal size by appropriate synthesis techniques, 35 selection of special organic compounds as templates in the zeolite synthesis, 36 an alkaline treatment at the synthesis step combined with partial activation, 37 working in the presence of air, 38 and modification of HZSM-5 with a small amount of antimony oxide. 39 Several studies 24,34 observed an increase of reaction rate (methanol conversion) with an increase in the Si/Al ratio.…”

Section: ■ Introductionmentioning

confidence: 99%

An Evaluation of Published Kinetic Models for Vapor Phase Methanol Conversion to Dimethyl Ether over the H-ZSM-5 Catalyst

et al. 2018

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The published kinetic models for methanol etherification over ZSM-5 zeolite were evaluated against our own experimental data. The process was investigated over a synthesized H-ZSM-5 zeolite using a laboratory fixed-bed reactor. The experiments were carried out at atmospheric pressure, temperatures of 170−270 °C, methanol feed concentrations up to 15 mol %, and gas phase velocity (WHSV) values in the range of 15−48 h −1 . The results showed a decrease of methanol conversion with respect to feed methanol concentration, with the single reaction product obtained in significant concentrations being dimethyl ether (no secondary products were observed in significant concentrations). The methanol conversion measurements were compared with theoretical predictions based on the main kinetic models published for methanol etherification over ZSM-5 zeolites with different acidities. As none of the published models fitted satisfactorily with our experimental data, we re-estimated the parameters of the tested models and applied a discrimination procedure in order to identify the most suitable one. The best quality of the fit was obtained by using an LH kinetic model based on the associative surface reaction mechanism. The adequacy of this kinetic model was confirmed by statistical and thermodynamic consistency criteria.

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Hierarchical mesoporous ZSM-5 for the dehydration of methanol to dimethyl ether

Cited by 20 publications

References 30 publications

Effect of the template on the hydrothermal synthesis of mixed molecular sieves for methanol dehydration

Effect of the template on the hydrothermal synthesis of mixed molecular sieves for methanol dehydration

Adjusting acidity and porosity of Al‐SBA‐15 catalyst for methanol to dimethyl ether reaction

An Evaluation of Published Kinetic Models for Vapor Phase Methanol Conversion to Dimethyl Ether over the H-ZSM-5 Catalyst

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