A novel method for the preparation of MOR/MCM-41 composite molecular sieve

Wang, Shan; Dou, Tao; Li, Yuping; Zhang, Ying; Li, Xiaofeng; Yan, Zichun

doi:10.1016/j.catcom.2004.11.005

Cited by 68 publications

(57 citation statements)

References 15 publications

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“…[ 23 ] In the primary method, the zeolite crystallization can take place either on the external surface [49][50][51][52] of a surfactant assembly or inside. [ 53 , 54 ] Moreover, the secondary methods include the use of surfactants to mediate the assembly of zeolite seeds into mesoporous structures, [ 55 , 56 ] coating zeolite crystals with a thin layer of mesopores with the help of surfactants, [57][58][59] and application of surfactants to swell and exfoliate layered zeolite precursors into delaminated zeolites. [ 60 , 61 ] In addition, methods concerning the synthesis of microporous/mesoporous hierarchical structures using organosilane surfactants containing a hydrophobic tail and a hydrophilic head (structured like a molecular template) also fall under this category.…”

Section: B)mentioning

confidence: 99%

Zeolitic Materials with Hierarchical Porous Structures

et al. 2011

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During the past several years, different kinds of hierarchical structured zeolitic materials have been synthesized due to their highly attractive properties, such as superior mass/heat transfer characteristics, lower restriction of the diffusion of reactants in the mesopores, and low pressure drop. Our contribution provides general information regarding types and preparation methods of hierarchical zeolitic materials and their relative advantages and disadvantages. Thereafter, recent advances in the preparation and characterization of hierarchical zeolitic structures within the crystallites by post-synthetic treatment methods, such as dealumination or desilication; and structured devices by in situ and ex situ zeolite coatings on open-cellular ceramic foams as (non-reactive as well as reactive) supports are highlighted. Specific advantages of using hierarchical zeolitic catalysts/structures in selected catalytic reactions, such as benzene to phenol (BTOP) and methanol to olefins (MTO) are presented.

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Section: B)mentioning

confidence: 99%

Zeolitic Materials with Hierarchical Porous Structures

et al. 2011

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“…Hydrothermal conditions were applied to synthesis of ZSM-12/MCM-41 composites [36]. We prepared such a sample for comparison purposes, adopting similar synthesis conditions for the composite.…”

Section: A Zsm-12/mcm-41 Composite Materialsmentioning

confidence: 99%

Properties of Desilicated ZSM-5, ZSM-12, MCM-22 and ZSM-12/MCM-41 Derivatives in Isomerization of α-Pinene

2008

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Limited information is available on the isomerization of a-pinene proceeding on zeolites and related desilicated materials. We wish therefore to report on the title reaction proceeding over ZSM-5, ZSM-12 and MCM-22 type zeolites, parent and modified by the sodium hydroxide treatment. The NaOH solutions of various concentrations (0.05-1 M) were used as a desilicating agent. Such treatments with basic solutions were applied: (i) under atmospheric pressure, and (ii) under hydrothermal conditions. It was shown that ZSM-12 was more resistant towards the basic solutions treatment, and its structure was retained over a whole range of NaOH concentrations studied. Nitrogen sorption revealed strong influence of the desilication process on the pore structure of modified materials-the mesopores system was formed in the zeolite crystals. Finally, catalytic studies were carried out using ZSM-5, ZSM-12, MCM-22, their desilicated derivatives and a ZSM-12/MCM-41 composite material. Catalytic properties of the samples studied were affected to a large extent by the NaOH treatment.

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“…2 presents the N 2 adsorption-desorption isotherms of various catalysts. It is known that the steep rise at P/P 0 = 0, step at P/P 0 & 0.35 and hysteresis loop within the P/P 0 ranging from 0.5 to 1.0 corresponds to the micropores, uniform mesopores, and secondary mesopores, respectively [17,20]. It thus can be seen that alkaline treatment created a small amount of secondary mesopores for Db(0.3) indicated by a small loop and Hb?M showed a sharp step at P/P 0 & 0.35, indicating the existence of uniform mesopores because of the existence of pure MCM41.…”

Section: Xrd Resultsmentioning

confidence: 99%

“…However, the physical mixture will cause a poor connection between micropores and mesopores. In order to eliminate the gap, some researchers directly synthesized composite molecular sieves by a hydrothermal crystallization [13] that showed a better performance in many reactions such as catalytic cracking [14,15], the hydrogenation of naphthalene [16], and the hydrodealkylation of heavy aromatic hydrocarbons [17].…”

Section: Introductionmentioning

confidence: 99%

Using β-MCM41 composite molecular sieves as supports of bifunctional catalysts for the hydroisomerization of n-heptane

Liu

Yao

Wang

2010

Reac Kinet Mech Cat

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b-MCM41 composite molecular sieves were hydrothermally synthesized using NaOH treated b zeolite as precursors, and Pt/b-MCM41 bifunctional catalysts were prepared by impregnation. Hb, desilicated Hb by NaOH treatment (Db), and the physical mixture of Hb and MCM41 (b?MCM41) were also used as control supports for bifunctional catalysts. All the catalysts were characterized by ICP, XRD, BET, nitrogen adsorption-desorption isotherm and NH 3 -TPD, and evaluated in the hydroisomerization of n-heptane using an atmospheric fixed bed flow reactor. Db, b?MCM41, or b-MCM41 supported Pt catalysts showed higher selectivity to isoheptanes than the counterpart Pt/Hb did due to the presence of mesopores in addition to the zeolite micropores. Moreover, Pt/b-MCM41 was demonstrated to be a much more selective catalyst among them because the connection between mesopores and micropores accelerated the diffusion of larger molecules of isoheptanes. Under optimal conditions, Pt/b-MCM41 provided a very high selectivity to isomerization of 96.5%, coupled with a considerable high conversion of n-heptane of 56.0%.

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A novel method for the preparation of MOR/MCM-41 composite molecular sieve

Cited by 68 publications

References 15 publications

Zeolitic Materials with Hierarchical Porous Structures

Zeolitic Materials with Hierarchical Porous Structures

Properties of Desilicated ZSM-5, ZSM-12, MCM-22 and ZSM-12/MCM-41 Derivatives in Isomerization of α-Pinene

Using β-MCM41 composite molecular sieves as supports of bifunctional catalysts for the hydroisomerization of n-heptane

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