Mesoporous Y zeolite with homogeneous aluminum distribution obtained by sequential desilication–dealumination and its performance in the catalytic cracking of cumene and 1,3,5-triisopropylbenzene

Qin, Zhengxing; Shen, Baojian; Gao, Xionghou; Lin, Feng; Wang, Baojie; Chen, Xu

doi:10.1016/j.jcat.2010.12.013

Cited by 147 publications

(69 citation statements)

References 29 publications

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“…60%, i.e., a value typical for alkalinetreated MFI zeolites. [31] As expected, [32] the alkaline treatments of pristine Y resulted in a minor development of mesoporosity; the highest S meso did not exceed 60 m 2 g −1 . Additionally, the N 2 isotherm suggests the presence of macroporosity (Figure 2), which was confirmed by TEM (AT4 in Figure 1).…”

Section: Resultssupporting

confidence: 78%

“…Qin et al [32] performed severe alkaline treatments (368 K, 0.5-1.3 m NaOH, 1-3 h) on a pristine zeolite Y (mesopore surface area = 18 m 2 g −1 , Si/Al = 3.1), but obtained a limited mesoporosity (S meso = 61 m 2 g −1 ), whereas crystallinity remained mostly unchanged. On the contrary, de Jong et al [33] performed alkaline treatments on a severely steamed and acid-leached zeolite USY (S meso = 213 m 2 g −1 , Si/Al = 28).…”

Section: Individual Acid and Base Treatments On Zeolite Ymentioning

confidence: 99%

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Hierarchical Y and USY Zeolites Designed by Post‐Synthetic Strategies

Verboekend

Vilé

Pérez‐Ramírez

2011

Adv Funct Materials

294

209

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Strategic combinations of affordable and scalable post‐synthetic modifications enabled to design a broad family of hierarchical Y and USY zeolites (FAU topology) independent on the Si/Al ratio. Pristine (Y, Si/Al = 2.4), steamed (USY, Si/Al = 2.6), and steamed and dealuminated (USY, Si/Al = 15 and 30) zeolites were exposed to a variety of acid (H4EDTA and Na2H2EDTA) and base (NaOH) treatments, which led to the introduction of mesopore surfaces up to 500 m2 g−1, while preserving the intrinsic zeolite properties. Pristine Y and USY zeolites (Si/Al ∼ 2.5) required mild dealumination (to Si/Al > 4 in the case of Y) to facilitate subsequent efficient desilication. Alkaline treatment of Y and USY zeolites with low Si/Al ratios (∼4–6) led to an abundance of Al‐rich debris, which could be removed by a subsequent mild acid wash. On the other hand, severely steamed and dealuminated, hence Si‐rich, USY zeolites (Si/Al = 15 and 30) proved extremely sensitive to the alkaline solution, displaying facile dissolution and substantial amorphization. For the latter group of ultra‐stable Y zeolites, the presence of TPA+ in the alkaline solution enables to protect the zeolite structures upon the introduction of mesoporosity by desilication, preserving crystallinity and micropore volume. The sorption and catalytic properties of the hierarchical Y and USY zeolites were superior compared to the conventional counterparts.

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Section: Resultssupporting

confidence: 78%

Section: Individual Acid and Base Treatments On Zeolite Ymentioning

confidence: 99%

Hierarchical Y and USY Zeolites Designed by Post‐Synthetic Strategies

Verboekend

Vilé

Pérez‐Ramírez

2011

Adv Funct Materials

294

209

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“…The dealumination of USY was carried out in AHFS solutions according to the method in [25]. Ten grams of USY was suspended in 100 g distilled water and heated to 338 K, then an appropriate amount of AHFS with varying concentrations (4, 8, and 12 wt %) was added dropwise.…”

Section: Ahfs Treatmentmentioning

confidence: 99%

“…Thus, these catalysts were further investigated. As for the parent USY and desilicated USY zeolites, the framework silicon-to-aluminum ratios determined by X-ray diffraction (XRD) (Si/Al XRD ) was lower than the bulk silicon-to-aluminum ratio determined by XRF, indicating the presence of a large amount of extra-framework silicon [22,25]. This suggests that the extra-framework silicon was easier to remove or part of exfoliated silicon recrystallized in the alkali-treatment [22,25,26].…”

Section: Introductionmentioning

confidence: 99%

Hydroconversion of Waste Cooking Oil into Green Biofuel over Hierarchical USY-Supported NiMo Catalyst: A Comparative Study of Desilication and Dealumination

et al. 2017

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Abstract:The hydroconversion of waste cooking oil into hydrocarbon fuel was investigated over the hierarchical USY zeolite-supported NiMo catalysts which were prepared by dealumination ((NH 4 ) 2 SiF 6 )/desilication (NaOH). The physical and acidity properties of the hierarchical catalysts were characterized by X-ray diffraction (XRD), the Brunauer-Emmett-Teller (BET) infrared spectroscopy of adsorbed pyridine (Py-IR), ammonia temperature-programmed desorption (NH 3 -TPD), and H 2 temperature-programmed reduction (H 2 -TPR). The Brønsted/Lewis (B/L) acid distribution was little affected by dealumination and the acid density decreased significantly. However, the highly-desilicated catalysts decreased the B/L ratio obviously. Therefore, many more Mo species in the NiMoO 4 − and MoO 3 phases were produced in the AHFS-treated catalysts, while more high-valence-state Mo species in the NiMoO 4 − phase were formed in the NaOH-treated catalysts.The AHFS-treated catalysts showed higher catalytic activity and better DCO 2 selectivity and selective cracking for jet fuel. The 42.3% selectivity of jet fuel and 13.5% selectivity of jet-range aromatics was achieved over the 8 wt % (NH 4 ) 2 SiF 6 -treated catalyst with 67% DCO 2 selectivity.

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“…The results of desilication showed decreases of the population of both microporosity and mesoporosity. The EDX and pore size distribution showed evidence of creating the mesoporosity, so the decreasing in the surface area explained by deposition of the Al species on the outer surface [3,[15][16][17][18][19][20][21]. In this work, the deposited Al was removed by acid treatment and the samples were evaluated in dimethyl ether (DME) to olefins.…”

Section: Introductionmentioning

confidence: 99%