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C.T. Kresge

Other affiliations: Mobil
Bio: C.T. Kresge is an academic researcher from Princeton University. The author has contributed to research in topics: Micelle & Molecular sieve. The author has an hindex of 2, co-authored 3 publications receiving 250 citations. Previous affiliations of C.T. Kresge include Mobil.

Papers
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Book ChapterDOI
TL;DR: The physical characterization of MCM-36 is described in this article, which unequivocally establishes its existence as a novel large pore pillared material with zeolite properties, and the pore size distribution plot obtained by Ar physisorption shows two distinct peak in the 6-7 A region.
Abstract: Publisher Summary This chapter describes the physical characterization of MCM-36, which unequivocally establishes its existence as a novel large pore pillared material with zeolite properties. MCM-36 is a pillared material obtained from MCM-22 layers. The preparation of MCM-36 involves a lamellar intermediate, designated MCM-22 precursor, produced in a hydrothermal process. The structural information concerning pore system of MCM-36 is revealed by adsorption methods. The layers in MCM-22 posses two kinds of pore systems. One consists of 10-ring interconnected channels within the layers. The second are isolated 12-ring cages on the surface, which result in pockets on the outside of MCM-22 crystal and internal supercages, accessible through 10-ring apertures, inside the crystal. Accordingly, the pore size distribution plot obtained for MCM-22 by Ar physisorption shows two distinct peak in the 6–7 A region. The complex pore structure of MCM-22 is also reflected in the unique three step uptake profile of bulky 2,2-dimethylbutane (DMB) observed in the dynamic sorption experiment.

181 citations

Book ChapterDOI
TL;DR: The influence of surfactant/silica molar ratio(Sur/Si) in M41S syntheses was studied in the simple synthesis system consisting of tetraethylorthosilicate (TEOS), water, and the cetyltrimethylammonium(CTMA) cation at 100°C.
Abstract: 1. Summary The influence of surfactant/silica molar ratio(Sur/Si) in M41S syntheses was studied in the simple synthesis system consisting of tetraethylorthosilicate(TEOS), water, and the cetyltrimethylammonium(CTMA) cation at 100°C. As the Sur/Si increased from 0.5 to 2, the siliceous products obtained were identified and could be classified into four separate groups: MCM-4 1(hexagonal), MCM-48(cubic), thermally unstable M4 1 S, and a molecular species, the organic octamer [(CTMA)SiO2, 5]8. One of the thermally unstable structures has been identified as a lamellar phase. These results are consistent with micellar phase transformations that occur at various surfactant concentrations and reinforce the concept that micelle structures serve as templating agents for the formation of M41S type materials.

78 citations

Book ChapterDOI
TL;DR: In this article, the ability of alkyltrimethylammonium surfactants to serve as structure directing agents for the formation of microporous or mesoporous molecular sieves frameworks was explored.
Abstract: Publisher Summary The chapter explores the ability of alkyltrimethylammonium surfactants of the type C n H 2n+I (CH 3 ) 3 NBr to serve as structure directing agents, or templates, for the formation of microporous or mesoporous molecular sieves frameworks At equivalent gel compositions and reaction conditions, it was observed that the alkyl chain length of the surfactant molecule dictated the nature of the silicate product obtained as indicated by the X-ray diffraction patterns Over the entire range of synthesis temperatures examined (100–200°C) the shortest alkyl chain length surfactant (n=6), produced amorphous or microporous zeolitic materials, such as ZSM-5 The zeolite contained the intact surfactant cation consistent with a commonly observed molecular templating effect At 100°C as the surfactant chain length was increased (n=8, 10, 12, 14, and 16), the formation of mesoporous molecular sieves (MCM-41) was observed In these cases, a combination of surfactant chain length and reaction conditions favor surfactant aggregation (micelles), and hence, the formation and utilization of supramolecular templates

4 citations


Cited by
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Journal ArticleDOI
TL;DR: Corma et al. as mentioned in this paper used the Dupont Award on new materials (1995), and the Spanish National Award “Leonardo Torres Quevedo” on Technology Research (1996) on technology research (1996), to recognize the performance of zeolites as catalysts for oil refining and petrochemistry.
Abstract: It is possible to say that zeolites are the most widely used catalysts in industry They are crystalline microporous materials which have become extremely successful as catalysts for oil refining, petrochemistry, and organic synthesis in the production of fine and speciality chemicals, particularly when dealing with molecules having kinetic diameters below 10 A The reason for their success in catalysis is related to the following specific features of these materials:1 (1) They have very high surface area and adsorption capacity (2) The adsorption properties of the zeolites can be controlled, and they can be varied from hydrophobic to hydrophilic type materials (3) Active sites, such as acid sites for instance, can be generated in the framework and their strength and concentration can be tailored for a particular application (4) The sizes of their channels and cavities are in the range typical for many molecules of interest (5-12 A), and the strong electric fields2 existing in those micropores together with an electronic confinement of the guest molecules3 are responsible for a preactivation of the reactants (5) Their intricate channel structure allows the zeolites to present different types of shape selectivity, ie, product, reactant, and transition state, which can be used to direct a given catalytic reaction toward the desired product avoiding undesired side reactions (6) All of these properties of zeolites, which are of paramount importance in catalysis and make them attractive choices for the types of processes listed above, are ultimately dependent on the thermal and hydrothermal stability of these materials In the case of zeolites, they can be activated to produce very stable materials not just resistant to heat and steam but also to chemical attacks Avelino Corma Canos was born in Moncofar, Spain, in 1951 He studied chemistry at the Universidad de Valencia (1967−1973) and received his PhD at the Universidad Complutense de Madrid in 1976 He became director of the Instituto de Tecnologia Quimica (UPV-CSIC) at the Universidad Politecnica de Valencia in 1990 His current research field is zeolites as catalysts, covering aspects of synthesis, characterization and reactivity in acid−base and redox catalysis A Corma has written about 250 articles on these subjects in international journals, three books, and a number of reviews and book chapters He is a member of the Editorial Board of Zeolites, Catalysis Review Science and Engineering, Catalysis Letters, Applied Catalysis, Journal of Molecular Catalysis, Research Trends, CaTTech, and Journal of the Chemical Society, Chemical Communications A Corma is coauthor of 20 patents, five of them being for commercial applications He has been awarded with the Dupont Award on new materials (1995), and the Spanish National Award “Leonardo Torres Quevedo” on Technology Research (1996) 2373 Chem Rev 1997, 97, 2373−2419

5,290 citations

Journal ArticleDOI
TL;DR: The chiral stationary phase for high-performance liquid chromatography showed good chiral recognition ability towards various racemates, including Na6(CO3)(SO4)2, Na2SO4, and Na2CO3.
Abstract: Wieslaw J. Roth,†,∥ Petr Nachtigall,‡ Russell E. Morris, and Jirí̌ Čejka*,† †J. Heyrovsky ́ Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejsǩova 3, CZ-182 23 Prague 8, Czech Republic ‡Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, Prague 2, 128 00, Czech Republic EaStCHEM School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Scotland Faculty of Chemistry, Jagiellonian University in Krakoẃ, ul. Ingardena 3,30-060 Krakoẃ, Poland

576 citations

Journal ArticleDOI
Carlo Perego1, Roberto Millini1
TL;DR: New synthesis strategies, especially designed for preparing materials with improved physico-chemical and textural properties, together with the catalytic features of the resulting materials, are described and discussed in the second part of the review.
Abstract: The discovery of ordered mesoporous materials has opened great opportunities for new applications in heterogeneous catalysis, thanks to their hitherto unprecedented intrinsic structural features. Evidence shows that, however, these materials have not met the researchers' expectations mainly because of the severe limitations related to the strength of acid sites and to the thermal/hydrothermal stability, significantly lower than those of zeolites and due to the amorphous nature of the mesostructured materials. These features are highlighted in the first part of this review, where the peculiarities of mesostructured materials are compared with those of zeolite catalysts in some reactions of industrial interest. New synthesis strategies, especially designed for preparing materials with improved physico-chemical and textural properties, together with the catalytic features of the resulting materials, are described and discussed in the second part of the review.

510 citations

Journal ArticleDOI
TL;DR: The present approach using a zeolite structure-directing functional group contained in a surfactant would be suitable for the synthesis of other related nanomorphous zeolites in the future.
Abstract: Zeolite MFI nanosheets of 2-nm thickness have been hydrothermally synthesized via cooperative assembly between silica and an organic surfactant, which is functionalized with a diquaternary ammonium group. The zeolite nanosheets have been further assembled into their ordered multilamellar mesostructure through hydrophobic interactions between the surfactant tails located outside the zeolite nanosheet. This assembly process involves successive transformations from an initially hexagonal mesophase to a multilamellar mesophase without crystallinity and then to a lamellar mesophase with a crystalline zeolite framework. The mesopore volume in the interlamellar space could be retained by supporting the zeolite nanosheets with silica pillars, as in pillared clays, even after surfactant removal by calcination. The mesopore diameters could be controlled according to the surfactant tail lengths. Due to the interlamellar structural coherence, the hierarchically mesoporous/microporous zeolite could exhibit small-angle X-ray diffraction peaks up to the fourth-order reflections corresponding to the interlayer distance. In addition, an Ar adsorption analysis and transmission electron microscopic investigation indicated that the pillars were highly likely to be built with an MFI structure. The present approach using a zeolite structure-directing functional group contained in a surfactant would be suitable for the synthesis of other related nanomorphous zeolites in the future.

443 citations

Journal ArticleDOI
TL;DR: In this paper, a review paper deals with proven and potential applications of mesoporous molecular sieves in catalysis, and is divided into two parts, respectively, dedicated to the design of solid catalysts and catalyst supports and to some relevant examples of catalytic processes.
Abstract: This review paper deals with proven and potential applications of mesoporous molecular sieves in catalysis. In addition to introduction and conclusion, the text is divided into two parts, respectively, dedicated to the design of solid catalysts and catalyst supports and to some relevant examples of catalytic processes.

440 citations