A novel method for enhancing the stability of ZSM-5 zeolites used for catalytic cracking of LPG: Catalyst modification by dealumination and subsequent silicon loading

Vafi, Leyla; Karimzadeh, Ramin

doi:10.1016/s1872-2067(15)61062-2

Cited by 13 publications

(5 citation statements)

References 40 publications

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“…Dealumination by bulky trichloroacetic acid has also been reported to be selective to the surface. 259 An alternative procedure is treatment with SiCl 4 , which can afford isomorphic substitution of framework Al by Si. SiCl 4 may encounter diffusional limitations in the zeolite micropores, leading to a Sienriched shell.…”

Section: Tuning Almentioning

confidence: 99%

“…Inagaki et al proposed a HNO 3 treatment aimed to dealuminate the crystal external surface. , This approach applies to OSDA-free synthesized ZSM-5 zeolite, possibly due to a lower amount of defects inside the crystal and/or to a different distribution of Al among framework positions. Dealumination by bulky trichloroacetic acid has also been reported to be selective to the surface . An alternative procedure is treatment with SiCl 4 , which can afford isomorphic substitution of framework Al by Si.…”

Section: Recent Advances In Zeolite Science Relevant To Catalytic Cra...mentioning

confidence: 99%

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Engineering Zeolites for Catalytic Cracking to Light Olefins

et al. 2017

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Propene is a key building block for the petrochemical industry whose demand is increasing strongly in recent years, even faster than that of ethene. The availability of propene is limited, and therefore, efforts to optimize its production are being pursued. On the occasion of the 75th anniversary of the first FCC unit, we analyze some recent advances that have been achieved in the understanding and development of zeolites aiming to increase the production of light olefins as petrochemical building blocks by means of catalytic cracking. We discuss a selected group of emerging strategies in zeolite engineering that have great prospects for research and that we consider could impact the sector in the near future. These include advances in crystal engineering and hierarchization achieved through bottom-up and top-down approaches, composite materials, tuning of the location of active sites among the different crystallographic positions available, and, importantly, how to characterize these modifications and their impact on the catalysis. Finally, we survey what advances are actually being implanted into the current industrial practice and conclude with a reflection on the future of zeolite research to satisfy light olefin demand.

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Section: Tuning Almentioning

confidence: 99%

Section: Recent Advances In Zeolite Science Relevant To Catalytic Cra...mentioning

confidence: 99%

Engineering Zeolites for Catalytic Cracking to Light Olefins

et al. 2017

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“…According to the IUPAC classification, Figure a shows characteristics of combined type I and type IV isotherms with type H4 hysteresis loops which indicate the formation of a hierarchical porous system containing both micropores and mesopores. Capillary condensation in inter‐/intra‐crystalline mesopore void spaces present in the initially de‐aluminated HZSM‐5 and hybrid materials can be assumed in the region 0.4 < P / P 0 < 0.95 . Figure b portrays the Barrett–Joyner–Halenda (BJH) pore size distribution plot of the parent HZSM‐5 and 2d (17% loading) using only the adsorption branch of the isotherm.…”

Section: Resultsmentioning

confidence: 99%

“…Capillary condensation in inter-/intra-crystalline mesopore void spaces present in the initially de-aluminated HZSM-5 and hybrid materials can be assumed in the region 0.4 < P/P 0 < 0.95. [50][51][52] Figure 12b portrays the Barrett-Joyner-Halenda (BJH) pore size distribution plot of the parent HZSM-5 and 2d (17% loading) using only the adsorption branch of the isotherm. The mean size of the micropores in HZSM-5 and the highest loaded composites was estimated to be about 17.34 Å (1.7 nm).…”

Section: Bet Analysismentioning

confidence: 99%

Supported dual‐acidic 1,3‐disulfoimidazolium chlorozincate@HZSM‐5 as a promising heterogeneous catalyst for synthesis of indole derivatives

Saikia

Puri

Borah

2019

Applied Organom Chemis

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HZSM‐5‐supported Brönsted and Lewis acidic ionic solid 1,3‐disulfoimidazolium chlorozincate materials ([dsim]2[ZnCl4]@HZSM‐5) were synthesized with various ratios (3, 6, 9, 17 and 50% w/w). The heterogeneous materials were characterized via a variety of spectroscopic techniques. Dual acidity of these materials was determined using specified techniques. These acidic solids were examined as stable heterogeneous catalysts for the Fischer indole reaction of equimolar amounts of phenylhydrazine hydrochloride and various aliphatic or aromatic ketones at 80–90°C in neat condition to produce substituted indole derivatives. The efficient 17% ionic salt‐loaded HZSM‐5 composite was easily reused for ten consecutive cycles with a slight loss of its activity. The recycled catalyst was further analysed using powder X‐ray diffraction and inductively coupled plasma optical emission spectrometric techniques.

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“…Acid leaching serves as a fundamental tool to modulate the acid property of zeolite crystals. − Inagaki et al found that the HNO 3 washing of ZSM-5 via organotemplate-free synthesis selectively removed the external acid sites, finally resulting in a high durability to coke formation during the catalytic cracking of n -hexane. The selective coverage/passivation of external acid sites by bulky organosilane, , organophosphorus compounds, , and nitrogenous compounds is an another effective method.…”

Section: Introductionmentioning

confidence: 99%

Promising Strategy to Synthesize ZSM-5@Silicalite-1 with Superior Catalytic Performance for Catalytic Cracking Reactions

Shen

et al. 2021

Ind. Eng. Chem. Res.

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with regular morphology was prepared through an innovative tandem synthesis strategy for the first time, which combined the insertion of almost all aluminum sites by organotemplate-free synthesis and the sequential crystallization of residual silica sites by organotemplate-oriented synthesis. Samples with different Si and Al distributions could be synthesized by adjusting the tandem synthesis process, including temperature, time, Na 2 O/SiO 2 , etc. The obtained Si-rich-ZSM-5 and conventional C-ZSM-5 with a similar Si/Al ratio but different Al distributions, which were demonstrated by X-ray fluorescence (XRF), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), and 1,3,5triisopropylbenzene catalytic cracking analysis, were employed in n-hexane catalytic cracking reaction. Si-rich-ZSM-5 showed a higher stability with a n-hexane conversion of 57.7% at 100 h compared with that of C-ZSM-5 (24.6%), which was attributed to its inactive outer shell. Besides, a high para-xylene selectivity in xylene for the Si-rich-ZSM-5 catalyst was obtained. Hence, this study provides a simple and cost-effective strategy to fabricate highly stable catalysts for cracking reactions.

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A novel method for enhancing the stability of ZSM-5 zeolites used for catalytic cracking of LPG: Catalyst modification by dealumination and subsequent silicon loading

Cited by 13 publications

References 40 publications

Engineering Zeolites for Catalytic Cracking to Light Olefins

Engineering Zeolites for Catalytic Cracking to Light Olefins

Supported dual‐acidic 1,3‐disulfoimidazolium chlorozincate@HZSM‐5 as a promising heterogeneous catalyst for synthesis of indole derivatives

Promising Strategy to Synthesize ZSM-5@Silicalite-1 with Superior Catalytic Performance for Catalytic Cracking Reactions

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