Effect of CO2 on the catalytic performance of Zn/ZSM-5 towards the conversion of methanol to aromatics

Jin, Runze; Ma, Ke; Chen, Zhongshun; Tang, Zhongqiang; Hu, Haobin; Wang, Jiaofei; Zhang, Zhuangzhuang; Dai, Chengyi; Ma, Xiaoxun

doi:10.1016/j.fuel.2022.126247

Cited by 12 publications

(6 citation statements)

References 47 publications

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“…The presence of H 2 may lead to the formation of alkanes by the catalytic hydrogenation of olefins produced in the olefinic cycle. However, CO or CO 2 in the reaction system can act as an acceptor of the hydrogen anion, consume the remaining H 2 in the reaction system in situ, reduce the occurrence of the hydrogen transfer reaction, prevent the olefin from reacting with hydrogen atoms to form alkanes, and promote the MTO dual-cycle mechanism …”

Section: Resultsmentioning

confidence: 99%

Direct and Highly Selective One-Step Production of Ethylbenzene from Syngas and Benzene

Zhao,

Ma,

et al. 2023

Ind. Eng. Chem. Res.

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Due to cost and energy consumption constraints, converting benzene into ethylbenzene using low-cost syngas instead of ethylene as an alkylation reagent is significant. However, when using syngas as the reaction raw material, generating ethylated side chains on the benzene ring is challenging. Instead, toluene/xylene becomes the primary product. We used a three-bed series connection method in a reactor, achieving one-step high selectivity of syngas and benzene to produce ethylbenzene. In the first bed layer (ZnAl2O4/SAPO-34), the syngas was first converted into methanol/dimethyl ether (DME) on ZnAl2O4. Then, it was further converted into low-carbon olefins on SAPO-34, with the microporous shape-selective effect of SAPO-34, inhibiting the generation of toluene/xylene in the alkylation of benzene with methanol/DME. At the same time, we proved that the absence of microporous shape-selective effect acid sites on the outer surface of S34 can lead to the occurrence of side reactions of benzene and methanol/DME methylation. In the second bed layer, SAPO-34 could continue to convert unconverted methanol/DME in the first bed layer into low-carbon olefins. In the third layer (ZSM-5), ethylene and benzene underwent highly selective alkylation on ZSM-5 to convert it into ethylbenzene. We found a “volcanic” curve relationship between the selectivity of ethylbenzene and the Brønsted acid site density of ZSM-5. On the one hand, Brønsted acid could catalyze the formation of ethylbenzene from benzene and ethylene; On the other hand, excessive Brønsted acid could lead to the isomerization of ethylbenzene to toluene/xylene. When the Brønsted acid showed a site density of 0.7 mmol/g, the selectivity of ethylbenzene was as high as 87%, with a byproduct of xylene showing only 0.3%, which is usually difficult to separate from ethylbenzene. Finally, the three-bed catalytic system showed no deactivation after 100 h.

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Section: Resultsmentioning

confidence: 99%

Direct and Highly Selective One-Step Production of Ethylbenzene from Syngas and Benzene

Zhao,

Ma,

et al. 2023

Ind. Eng. Chem. Res.

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“…This is because the introduced Zn species interacts with the Brønsted acid sites and generates dehydrogenation sites, which improves the efficiency of the dehydrogenation step in the aromatization process increasing aromatic selectivity. 36,39,40 With the increase of Zn/Al ratios, the selectivity of 3DOMmC-Zn-Z5 for BTX and aromatics increases firstly and then decreases. When the Zn/Al ratio is 0.5, 3DOMmC-Zn-Z5-0.5 exhibits the highest BTX (29.90%) and aromatics (43.55%) selectivity, which is much higher than that of JZ-3DOMmC-Z5 (the selectivity of BTX and aromatics is 26.31% and 38.74%, respectively).…”

Section: Catalytic Performance In the Methanol To Aromatics Reactionmentioning

confidence: 99%

Novel-ordered hierarchical ZSM-5 zeolite with interconnected macro–meso–microporosity for the enhanced methanol to aromatics reaction

Wang,

Li,

Ouyang

et al. 2024

Catal. Sci. Technol.

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“…Aromatics, especially toluene and xylene, play pivotal roles as primary raw materials in the petrochemical industry and serve as vital intermediates in the production of fine chemicals. − Their applications encompass a wide range of industries, including the production of polyester fibers, resins, coatings, dyes, pesticides, and more. In recent years, both the domestic and global demand for these compounds has witnessed a substantial upsurge.…”

Section: Introductionmentioning

confidence: 99%

Diminishing Ethylbenzene in Methylation of Benzene with Methanol: Disentanglement of Methanol to Olefin Reactions over MFI Gallium Silicate

Shao,

He,

Wang

et al. 2024

Ind. Eng. Chem. Res.

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Methylation of benzene with methanol provides an efficient route to utilize the surplus benzene in aromatic united plants, facing a primary challenge from the ethylbenzene (EB) as the side product. This work discovers that EB selectivity can be significantly limited utilizing nanosized MFI type gallium silicate. Experiment and simulation results reveal diminished EB owing to the acid strength and diffusion capability. Gallium silicate zeolite, with much weaker acidity than aluminum silicate zeolite, favored higher energy barriers for polymethylbenzene formation, important precursors in methanol to olefin reactions, effectively suppressing ethene and EB. Additionally, the smaller particle size led to improved diffusion, facilitating the effusion of heavy aromatics. Therefore, nanosized MFI type gallium silicate could achieve an EB selectivity lower than 0.1% with toluene and xylene selectivities exceeding 90%. Our study provided a feasible strategy for adjusting the coordination–competition relationship between the main and side reaction mechanisms based on the synergistic effect of active sites and mass transfer.

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Effect of CO2 on the catalytic performance of Zn/ZSM-5 towards the conversion of methanol to aromatics

Cited by 12 publications

References 47 publications

Direct and Highly Selective One-Step Production of Ethylbenzene from Syngas and Benzene

Direct and Highly Selective One-Step Production of Ethylbenzene from Syngas and Benzene

Novel-ordered hierarchical ZSM-5 zeolite with interconnected macro–meso–microporosity for the enhanced methanol to aromatics reaction

Diminishing Ethylbenzene in Methylation of Benzene with Methanol: Disentanglement of Methanol to Olefin Reactions over MFI Gallium Silicate

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