Effect of the Si/Al ratio in Ga/mesoporous HZSM-5 on the production of benzene, toluene, and xylene <i>via</i> coaromatization of methane and propane

Gim, Min Yeong; Song, Changyeol; Lim, Yong Hyun; Lee, Kwan Young; Kim, Do Heui

doi:10.1039/c9cy01619h

Cited by 18 publications

(8 citation statements)

References 59 publications

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“…The accessibility, strength, distribution, and nature of zeolite acid sites play a crucial role in many catalytic reactions [10][11][12]. Especially for HZSM-5 with a low Si/Al ratio, the aromatization could more likely occur on its strong acid sites and the aromatics could be produced with high selectivity [13]. While increasing the Si/Al ratio of HZSM-5 could reduce the density of acid sites, so that the selectivity of light alkenes was increased [14,15].…”

Section: Introductionmentioning

confidence: 99%

Relationship between Acidity and Activity on Propane Conversion over Metal-Modified HZSM-5 Catalysts

Zhou

Zhang

et al. 2021

Catalysts

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A systematic study of the comparative performances of different metal-impregnated HZSM-5 catalysts (Zn, Ga, Mo, Co, and Zr) for propane conversion is presented. The physicochemical properties of catalysts were characterized by means of XRD, BET, SEM, TEM, FTIR, XPS, 27Al MAS NMR, NH3-TPD and Py-FTIR. It was found that the acidities of the catalysts were significantly influenced by loading metal. More specifically, Mo-, Co- or Zr-modified catalysts showed a large metal size and low acidic density, resulting high olefin selectivity, while Zn- or Ga-modified catalysts maintained their small metal size and acidic density, and mainly reduced B/L due to the Lewis acid sites created by Zn or Ga species, resulting in high aromatics selectivity. Experimental results also showed that there is a balance between metals size and medium and strong acidity on propane conversion. Moreover, based on the different acidity of metal-modified HZSM-5 catalysts, the mechanism of propane conversion was also discussed.

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Section: Introductionmentioning

confidence: 99%

Relationship between Acidity and Activity on Propane Conversion over Metal-Modified HZSM-5 Catalysts

Zhou

Zhang

et al. 2021

Catalysts

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“…However, these are considered "indirect" evidences, as they do not directly indicate the insertion of the carbon atoms of methane into aromatics. Positive values of methane conversion were observed at temperatures of 873 K or below in the presence of ethane, [38][39][40][41] propane, [42][43][44][45][46][47][48] higher alkanes, [38,[49][50][51] or olefins. [52] Generally, considerably higher values have been reported in earlier studies, including the aforementioned work by Choudhary et al [28] Anunziata et al carried out several coaromatization studies employing Zn/ZSM-11 catalysts since the late 1990s.…”

Section: Change In Methane Conversion Upon Co-feedingmentioning

confidence: 99%

“…[43,52] Meanwhile, recent studies have reported relatively low methane conversions in co-aromatization reactions. Starting in 2017, Gim et al tailored several properties of Ga/ZSM-5 for its application in methane aromatization with a small amount of propane additive and found that methane conversion hardly surpassed 10 % at 823 K. [45][46][47][48] Xu et al also investigated the reaction with a significantly higher proportion of propane by applying Zn-based core-shell catalysts. A methane conversion of 15.6 % at 823 K was observed over silicalite-1-coated Zn/ ZSM-5 (which remains the highest among recent methane coaromatization studies), [54] whereas other catalysts yielded values ranging from 5-10 %.…”

Section: Change In Methane Conversion Upon Co-feedingmentioning

confidence: 99%

Application of co‐feeds in the catalytic conversion of light alkanes to aromatics: A comprehensive review

Lim,

Ryu,

Hwang

et al. 2024

ChemCatChem

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Catalytic conversion of light alkanes (C1‐C3) to aromatics offers an attractive valorization route for abundant gas resources and has been a prevalent topic of research over the past few decades. Despite considerable advancements in the understanding of these reactions, several fundamental and practical hurdles have prevented their industrial application. Among the numerous attempts to resolve these issues, co‐feeding certain additives yields promising results, including the activation of alkanes under milder conditions, an increase in catalytic stability, and a shift in product distribution towards more desirable compounds. Systematic studies have elucidated the precise working mechanism of the co‐feeds in aromatization systems, explaining the experimentally observed results. This review provides an extensive compilation of information on the application of co‐feeds in light alkane aromatization, which has accumulated in the literature since the pioneering reports in the 1990s. Detailed summaries are provided for each additive, ranging from hydrocarbons to oxidants. Viable strategies for future work in this field, aiming to bridge the gap between academic studies and industrial applications, are also discussed.

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“…9−11 At the same time, due to the growing demand for downstream products, the growth in demand for BTX is much more than that for refined oil. 12,13 The high content of potential aromatics in LCO makes it a possible source for the production of light aromatics. As a result, the techniques to convert LCO into BTX have gradually become a hot research field.…”

Section: Introductionmentioning

confidence: 99%

“…Light cycle oil (LCO), as the main byproduct in fluid catalytic cracking processes, is majorly composed of condensed aromatics (>75%), most of which are bi- or tricyclic homologues such as naphthalene, alkylnaphthalene, anthracene, and phenanthrene. − LCO used to be added into diesel oil for viscosity adjustment; however, for diesel upgrading, this demand has witnessed a steep decrease during the last decade owing to its drawbacks like the low cetane number and poor ignition performance. , Meanwhile, light aromatics such as benzene, toluene, and xylene (BTX) are important raw materials in the chemical market, and demand will continue to increase in the future . For example, the worldwide increasing demand in paraxylene (PX) will maintain a growth of 3.5% over the next 5 years as a result of its importance as a major chemical in producing plastics and synthetic fibers. − At the same time, due to the growing demand for downstream products, the growth in demand for BTX is much more than that for refined oil. , The high content of potential aromatics in LCO makes it a possible source for the production of light aromatics. As a result, the techniques to convert LCO into BTX have gradually become a hot research field.…”

Section: Introductionmentioning

confidence: 99%

Identifying the Location of Real Active Sites in ZSM-5 Zeolites for Tetralin Conversion into Light Aromatics

Guan

Zhang

et al. 2023

Energy Fuels

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Light cycle oil (LCO) can no longer be used as fuel additives for diesel upgrading, and hence, the catalytic cracking of LCO into light aromatics has become an urgent job for its proper utilization. In this work, toward the rational design of catalysts for LCO cracking, various ZSM-5 zeolites were prepared and utilized in tetralin (as a presentative compound of LCO) cracking to determine the essential locations of active sites. Results show that tetralin could hardly penetrate into the micropores constituted by the 10-member-ring channels of ZSM-5 owing to the large molecular size. Instead, this reaction majorly proceeds via the acid sites residing on the external surfaces rather than those in the intracrystal mesopores. Meanwhile, the external acid sites also possess the advantage of rapid diffusion, which significantly decreases the formation of coke and promotes the catalytic lifetime. Consequently, the morphologies of ZSM-5 play a pivotal role in catalytic performances, among which the nanosized ZSM-5 catalyst was the most outstanding candidate, exhibiting a tetralin conversion of 87.0%, benzene/toluene/xylene total yields of 51.3%, and a lifetime of 22 h as a result of the most abundant external acid sites. These findings disclosed the locations of real active sites in ZSM-5 zeolites in the cracking of tetralin and developed methods to enhance the catalytic performances, which are helpful for the rational design of catalysts for tetralin cracking.

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Effect of the Si/Al ratio in Ga/mesoporous HZSM-5 on the production of benzene, toluene, and xylene via coaromatization of methane and propane

Abstract: In this work, a series of GaOy supported on mesoporous HZSM-5 (GaOy/meso-XHZSM-5; Si/Al (X), X = 10, 20, 30, and 40) catalysts with different Si/Al molar ratios were prepared for use in the coaromatization of methane and propane.

Cited by 18 publications

References 59 publications

Relationship between Acidity and Activity on Propane Conversion over Metal-Modified HZSM-5 Catalysts

Relationship between Acidity and Activity on Propane Conversion over Metal-Modified HZSM-5 Catalysts

Application of co‐feeds in the catalytic conversion of light alkanes to aromatics: A comprehensive review

Identifying the Location of Real Active Sites in ZSM-5 Zeolites for Tetralin Conversion into Light Aromatics

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