Simultaneously enhanced aromatics selectivity and catalyst lifetime in methanol aromatization over [Zn, Al]-ZSM-5 via isomorphous substitution with optimized acidic properties and pore structure

Liu, Xinhui; Chen, Yan; Wang, Yilin; Zhang, Peng; Yan, Siyan; Zhuang, Jianguo; Zhu, Xuedong; Zhu, Xuedong

doi:10.1016/j.fuel.2023.128758

Cited by 5 publications

(5 citation statements)

References 75 publications

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“…Figure a exhibits the XRD spectra of all samples, depicting their high crystallinity through distinct diffraction peaks observed at 2θ values of 8.0, 8.8, 23.0, 23.8, and 24.3, corresponding to (101), (200), (501), (151), and (303) planes of the MFI topology structure, − respectively, confirming the propitious synthesis of MFI zeolites. In addition, the absence of diffraction peaks attributed to gallium oxide phases implied the effective integration of gallium atoms into the framework or their highly dispersed nature within the zeolites.…”

Section: Resultsmentioning

confidence: 79%

“…This observed phenomenon aligned with established findings in prior literature regarding zeolite synthesis and heteroatom substitution. Previous studies had demonstrated that the incorporation of larger atoms, such as Fe, Ga, or Ti, into the MFI structure typically induced cell expansion, , while smaller atoms, like B, tended to result in contraction , within zeolite framework. Hence, the observed shift in the diffraction peaks provided compelling evidence supporting the successful incorporation of gallium atoms into the zeolite framework via isomorphous substitution.…”

Section: Resultsmentioning

confidence: 99%

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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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Section: Resultsmentioning

confidence: 79%

Section: Resultsmentioning

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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“…Introducing Zn species to Cu/FeO x catalysts facilitated the formation of both Brønsted and Lewis acidic sites, especially for Brønsted acidic sites (Table ). Introducing Zn species formed more Brønsted acidic sites in Cu/Zn-FeO x catalysts . The presence of Zn species in Cu/Zn-FeO x catalysts significantly impacted the physicochemical properties of the catalysts by increasing the dispersion of Cu species and the formation of more developed pore structures and more acidic sites.…”

Section: Resultsmentioning

confidence: 99%

“…Introducing Zn species formed more Brønsted acidic sites in Cu/Zn-FeO x catalysts. 34 The presence of Zn species in Cu/Zn-FeO x catalysts significantly impacted the physicochemical properties of the catalysts by increasing the dispersion of Cu species and the formation of more developed pore structures and more acidic sites. This might also affect the catalytic behaviors of Cu-based catalysts for catalyzing the conversion of PET.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Synergy between Cu and Lewis Acidic Sites in Cu/Zn-FeO_x Catalysts for the Selective Conversion of Poly(ethylene terephthalate) Waste to p-Xylene and Ethylene Glycol

Shao,

Kong,

Fan

et al. 2024

ACS Sustainable Chem. Eng.

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Poly(ethylene terephthalate) (PET)-derived plastics are an important fraction of plastic waste. Selective hydrogenolysis of PET to p-xylene (xylene) and ethylene glycol (EG) could partially recover its value as a chemical feedstock. Herein, Cu/Zn-FeO x catalysts were prepared for the conversion of PET to xylene and EG in 1,4-dioxane at 180−200 °C. The results showed that Zn in Cu/Zn-FeO x created more Lewis acidic sites and enhanced the dispersion of metallic Cu species by developing a porous structure and promoting the reduction of CuO. Cu 2.0 /Zn 1.0 -FeO x was much more active than Cu/FeO x for the conversion of PET to xylene at 180 °C (yield: 93.7% vs 40.7%) but also for further hydrogenolysis of EG, diminishing EG in products. Cu 1.0 /Zn 2.0 -FeO x with a lower availability of Cu sites could also achieve a xylene yield of 98.6% and retain more EG (yield: 53.3%). A kinetic study showed that hydrogenolysis of intermediates like p-tolylmethanol but not hydrogenation was the rate-determining step. The lower activation energy for hydrogenolysis over Cu 2.0 /Zn 1.0 -FeO x than over Cu/FeO x (57.8 vs 65.8 kJ•mol −1 ) rendered the higher turnover frequency for xylene formation. In situ IR characterization showed that Lewis acidic sites induced by Zn addition were important for the adsorption/activation of O-containing functionalities (i.e., C−OH) of the reaction intermediates and consequently further hydrogenolysis.

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“…In addition to the sharp peak at 0.56 nm, another peak centering at 20 nm as well as a shoulder at 70 nm can also be observed for MTBBP-ZSM-5, indicating the existence of meso-to marco-pores. Hence, MTBBP-ZSM-5 can be regarded as a hierarchical zeolite [41][42][43].…”

Section: Resultsmentioning

confidence: 99%

Disinfectant-Assisted Preparation of Hierarchical ZSM-5 Zeolite with Excellent Catalytic Stabilities in Propane Aromatization

Zhang,

Zhuang,

et al. 2024

Nanomaterials

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A series of quaternary ammonium or phosphonium salts were applied as zeolite growth modifiers in the synthesis of hierarchical ZSM-5 zeolite. The results showed that the use of methyltriphenylphosphonium bromide (MTBBP) could yield nano-sized hierarchical ZSM-5 zeolite with a “rice crust” morphology feature, which demonstrates a better catalytic performance than other disinfect candidates. It was confirmed that the addition of MTBBP did not cause discernable adverse effects on the microstructures or acidities of ZSM-5, but it led to the creation of abundant meso- to marco- pores as a result of aligned tiny particle aggregations. Moreover, the generation of the special morphology was believed to be a result of the coordination and competition between MTBBP and Na+ cations. The as-synthesized hierarchical zeolite was loaded with Zn and utilized in the propane aromatization reaction, which displayed a prolonged lifetime (1430 min vs. 290 min compared with conventional ZSM-5) and an enhanced total turnover number that is four folds of the traditional one, owing to the attenuated hydride transfer reaction and slow coking rate. This work provides a new method to alter the morphological properties of zeolites with low-cost disinfectants, which is of great potential for industrial applications.

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Simultaneously enhanced aromatics selectivity and catalyst lifetime in methanol aromatization over [Zn, Al]-ZSM-5 via isomorphous substitution with optimized acidic properties and pore structure

Cited by 5 publications

References 75 publications

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

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

Synergy between Cu and Lewis Acidic Sites in Cu/Zn-FeO_x Catalysts for the Selective Conversion of Poly(ethylene terephthalate) Waste to p-Xylene and Ethylene Glycol

Disinfectant-Assisted Preparation of Hierarchical ZSM-5 Zeolite with Excellent Catalytic Stabilities in Propane Aromatization

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Simultaneously enhanced aromatics selectivity and catalyst lifetime in methanol aromatization over [Zn, Al]-ZSM-5 via isomorphous substitution with optimized acidic properties and pore structure

Cited by 5 publications

References 75 publications

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

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

Synergy between Cu and Lewis Acidic Sites in Cu/Zn-FeOx Catalysts for the Selective Conversion of Poly(ethylene terephthalate) Waste to p-Xylene and Ethylene Glycol

Disinfectant-Assisted Preparation of Hierarchical ZSM-5 Zeolite with Excellent Catalytic Stabilities in Propane Aromatization

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Synergy between Cu and Lewis Acidic Sites in Cu/Zn-FeO_x Catalysts for the Selective Conversion of Poly(ethylene terephthalate) Waste to p-Xylene and Ethylene Glycol