Synthesis, characterization, and catalytic properties of hydrothermally stable macro–meso–micro-porous composite materials synthesized via in situ assembly of preformed zeolite Y nanoclusters on kaolin

Tan, Qingfeng; Bao, Xiaojun; Song, Tengchun; Fan, Yu; Shi, Gang; Shen, Baojian; Liu, Conghua; Gao, Xionghou

doi:10.1016/j.jcat.2007.07.014

Cited by 123 publications

(74 citation statements)

References 38 publications

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“…Recently, we have reported that silica-aluminas with about 5 nm of mesopore prepared using malic acid influence the production of branched hydrocarbons in catalytic cracking of n-dodecane [1,2]. Hosseinpour et al [9], and Q. Tang et al [10], have also reported the matrix effect. However, these reports are not enough to understand the role of the matrix in catalytic cracking.…”

Section: Introductionmentioning

confidence: 95%

“…However, simultaneous usage of zeolite and amorphous silica-alumina maintained the crystallinity of zeolite and recrystallized zeolite, indicating that amorphous silica-alumina still has great potential for use in catalytic cracking [8]. On the other hand, growing zeolite crystals with mesopores was tried, using zeolite with micropores as a seed crystal or by assembling zeolite precursor [10,[28][29][30][31][32]. Surface-active agents, such as tetraalkylammonium salts were used with the seed crystals to grow the zeolite structure, and higher hydrothermal stability was obtained, compared with MCM-41, which had lower hydrothermal stability.…”

Section: Concerning Reaction Mechanismsmentioning

confidence: 99%

“…The pores of zeolite, which mainly consist of micropores, are disadvantageous to carry and diffuse hydrocarbons with large molecular structures, such as vacuum gas oil or atmospheric residue [5,6]. Although silica-alumina is used to control the activity of zeolite or selectivity of catalytic cracking reactions, there are fewer academic studies of silica-alumina than those of zeolite in this field [1,2,[7][8][9][10]. Recently, we have reported that silica-aluminas with about 5 nm of mesopore prepared using malic acid influence the production of branched hydrocarbons in catalytic cracking of n-dodecane [1,2].…”

Section: Introductionmentioning

confidence: 99%

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Large Mesopore Generation in an Amorphous Silica-Alumina by Controlling the Pore Size with the Gel Skeletal Reinforcement and Its Application to Catalytic Cracking

Ishihara¹,

Hashimoto²,

Nasu³

2012

Catalysts

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Tetraethoxy orthosilicate (TEOS) was used not only as a precursor of silica, but also as an agent which reinforces the skeleton of silica-gel to prepare an aerogel and resultant silica and silica-alumina with large pore size and pore volume. In this gel skeletal reinforcement, the strength of silica aerogel skeleton was enhanced by aging with TEOS/2-propanol mixed solution to prevent the shrink of the pores. When silica aerogel was reinforced by TEOS solution, the pore diameter and pore volume of calcined silica could be controlled by the amount of TEOS solution and reached 30 nm and 3.1 cm 3 /g. The results from N 2 adsorption measurement indicated that most of pores for this silica consisted of mesopores. Silica-alumina was prepared by the impregnation of an aluminum tri-sec-butoxide/2-butanol solution with obtained silica. Mixed catalysts were prepared by the combination of β-zeolite (26 wt%) and prepared silica-aluminas with large mesopore (58 wt%) and subsequently the effects of their pore sizes on the catalytic activity and the product selectivity were investigated in catalytic cracking of n-dodecane at 500 °C. The mixed catalysts exhibited not only comparable activity to that for single zeolite, but also unique selectivity where larger amounts of branched products were formed.

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Section: Introductionmentioning

confidence: 95%

Section: Concerning Reaction Mechanismsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Large Mesopore Generation in an Amorphous Silica-Alumina by Controlling the Pore Size with the Gel Skeletal Reinforcement and Its Application to Catalytic Cracking

Ishihara¹,

Hashimoto²,

Nasu³

2012

Catalysts

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“…Figure 4 shows CO2-TPD desorption curves of pure Y zeolite, where three small peaks have been detected at 200, 680 and 780°C respectively. These peaks corresponded to weak, medium and strong acid sites [12,13]. That means a view basic sites are found on pure Y zeolite catalyst.…”

mentioning

confidence: 99%

“…Since pure Y zeolite has one desorption peak starting at around 150 °C. This peak is shifted to 250 °C for the other alkali metal ions exchanged Y zeolites, corresponding to mild acid site [12,13]. It can be observed, that the amount of NH3 adsorbed decreased by increasing atomic size of alkali metal ion exchanged.…”

mentioning

confidence: 99%

Effect of Alkali Metal Ions on Different Zeolites for Alkylation of Cumene

Abdalah

2012

Al-Azhar Bulletin of Science

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The effects of alkali metal treatment on different zeolite catalysts are investigated to better understand the nature of alkali metal species for the selective catalytic alkylation of cumene by ethylene.H-ZSM5, Y and BEA zeolite catalysts with various molar ratios of K, Rb, and Cs are prepared by ion exchange method and calcined at 550 o C in air atmosphere for 2 h. The study was carried out at 300, 350, 400 and 450 °C for reaction times of 2 hours. Cumene conversion was found to increase with all different alkali metal additions and the reaction temperatures. The catalysts are characterized by temperature-programmed desorption of NH3/ or CO2 (TPD), Fourier transform infrared (FT-IR) after pyridine adsorption and inductively-coupled plasma emission spectrometry (i.c.p.e.s.). The FTIR results are compared to Lewis and Broensted acid sites. Furthermore, the relation between atomic size of alkali metal ion exchanged and the basicity of the catalyst is discussed. Among them the 0.025 M Cs exchanged is found as very active catalyst for alkylation of cumene with ethylene resulted in amyl benzene, styrene and ethyl benzene.

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