Zeolite acid strength and reaction mechanisms in catalysis

The heterogeneous catalysts of greatest practical importance are acidic zeolites, and these cannot be studied using the traditional methods of UHV surface science. As recently as 1994 there was near universal agreement that zeolites were superacids, and that many of the most important reaction mechanisms in catalysis were based upon simple carbenium ions and other exotic high-energy intermediate species. This Paper reviews a series of investigations, many of them using solid-state NMR, that led to the reclassification of zeolite acidity and a theoretical basis for understanding carbenium ion stability in these fascinating solids. Building on this better understanding of zeolite acid strength and the types of carbenium ions that are reasonable intermediates in zeolites, it was possible to elucidate many of the features of a challenging mechanistic problem: methanol to hydrocarbon catalysis.

[1]  W. Hölderich,et al.  Industrial application of solid acid–base catalysts , 1999 .

[2]  Weiguo Song,et al.  Selective Synthesis of Methylnaphthalenes in HSAPO-34 Cages and Their Function as Reaction Centers in Methanol-to-Olefin Catalysis , 2001 .

[3]  Teng Xu,et al.  NMR Observation of Indanyl Carbenium Ion Intermediates in the Reactions of Hydrocarbons on Acidic Zeolites , 1994 .

[4]  B. Arstad,et al.  Methanol-to-hydrocarbons reaction over SAPO-34. Molecules confined in the catalyst cavities at short time on stream , 2001 .

[5]  Michael Stöcker,et al.  Methanol-to-hydrocarbons: catalytic materials and their behavior 1 Dedicated to my wife Wencke Ophau , 1999 .

[6]  H. Gies,et al.  One- and Two-Dimensional High-Resolution Solid-State NMR Studies of Zeolite Lattice Structures , 1991 .

[7]  B. Arstad,et al.  The reactivity of molecules trapped within the SAPO-34 cavities in the methanol-to-hydrocarbons reaction. , 2001, Journal of the American Chemical Society.

[8]  Avelino Corma,et al.  Inorganic Solid Acids and Their Use in Acid-Catalyzed Hydrocarbon Reactions , 1995 .

[9]  G. Kramer,et al.  Reactivity Theory of Zeolitic Broensted Acidic Sites , 1995 .

[10]  J. Sauer,et al.  Comparing the Acidities of Microporous Aluminosilicate and Silico-Aluminophosphate Catalysts: A Combined Quantum Mechanics-Interatomic Potential Function Study , 1998 .

[11]  Teng Xu,et al.  Benzenium Ion Chemistry on Solid Metal Halide Superacids: In Situ 13C NMR Experiments and Theoretical Calculations , 1997 .

[12]  Joachim Sauer,et al.  Molecular models in ab initio studies of solids and surfaces: from ionic crystals and semiconductors to catalysts , 1989 .

[13]  Weiguo Song,et al.  Synthesis of a Benzenium Ion in a Zeolite with Use of a Catalytic Flow Reactor , 1998 .

[14]  Weiguo Song,et al.  PULSE-QUENCH CATALYTIC REACTOR STUDIES REVEAL A CARBON-POOL MECHANISM IN METHANOL-TO-GASOLINE CHEMISTRY ON ZEOLITE HZSM-5 , 1998 .

[15]  J. Klinowski.  Solid-State NMR Studies of Molecular Sieve Catalysts , 1991 .

[16]  P. Schettler,et al.  Reactions of butadiene in zeolite catalysts by in situ variable-temperature solid-state nuclear magnetic resonance spectrometry , 1990 .

[17]  Weiguo Song,et al.  A Persistent Carbenium Ion on the Methanol-to-Olefin Catalyst HSAPO-34: Acetone Shows the Way , 2001 .

[18]  L. Curtiss,et al.  Ab initio and density functional study of the activation barrier for ethane cracking in cluster models of zeolite H-ZSM-5 , 2000 .

[19]  J. Nicholas,et al.  Kinetic NMR and density functional study of benzene H/D exchange in zeolites, the most simple aromatic substitution , 1995 .

[20]  E. Munson,et al.  Toward a Systematic Chemistry of Organic Reactions in Zeolites: In situ NMR Studies of Ketones , 1994 .

[21]  Avelino Corma,et al.  From Microporous to Mesoporous Molecular Sieve Materials and Their Use in Catalysis. , 1997, Chemical reviews.

[22]  O. Terasaki,et al.  Structural elucidation of microporous and mesoporous catalysts and molecular sieves by high-resolution electron microscopy. , 2001, Accounts of chemical research.

[23]  Teng Xu,et al.  Preparation and NMR characterization of carbenium ions on metal halide powders , 1995 .

[24]  E. Munson,et al.  Carbon monoxide is neither an intermediate nor a catalyst in MTG chemistry on zeolite HZSM-5 , 1991 .

[25]  D. B. Ferguson,et al.  Physical Organic Chemistry of Solid Acids: Lessons from in situ NMR and Theoretical Chemistry , 1996 .

[26]  J. Nicholas,et al.  Solvent-assisted proton transfer in catalysis by zeolite solid acids , 1997, Nature.

[27]  Weiguo Song,et al.  An oft-studied reaction that may never have been: direct catalytic conversion of methanol or dimethyl ether to hydrocarbons on the solid acids HZSM-5 or HSAPO-34. , 2002, Journal of the American Chemical Society.

[28]  J. Nicholas,et al.  Acid-base chemistry of a carbenium ion in a zeolite under equilibrium conditions: verification of a theoretical explanation of carbenium ion stability. , 2001, Journal of the American Chemical Society.

[29]  Weiguo Song,et al.  Roles for Cyclopentenyl Cations in the Synthesis of Hydrocarbons from Methanol on Zeolite Catalyst HZSM-5 , 2000 .

[30]  Weiguo Song,et al.  Methylbenzenes Are the Organic Reaction Centers for Methanol-to-Olefin Catalysis on HSAPO-34 , 2000 .

[31]  S. Kolboe,et al.  On the Reaction Mechanism for Hydrocarbon Formation from Methanol over SAPO-34 , 1996 .

[32]  Ivar M. Dahl,et al.  On the Reaction Mechanism for Hydrocarbon Formation from Methanol over SAPO-34 2. Isotopic Labeling Studies of the Co-reaction of Propene and Methanol , 1994 .

[33]  Ø. Mikkelsen,et al.  The conversion of methanol to hydrocarbons over zeolite H-beta , 1999 .

[34]  T. Mole,et al.  Aromatic co-catalysis of methanol conversion over zeolite catalysts , 1983 .

[35]  R. F. Sullivan,et al.  A New Reaction That Occurs in the Hydrocracking of Certain Aromatic Hydrocarbons , 1961 .

[36]  E. Munson,et al.  In situ variable-temperature MAS carbon-13 NMR study of the reactions of isobutylene in zeolites HY and HZSM-5 , 1991 .

[37]  K. C. Hunter,et al.  Properties of C−C Bonds in n-Alkanes: Relevance to Cracking Mechanisms , 2002 .

[38]  J. F. Haw,et al.  The Prediction of Persistent Carbenium Ions in Zeolites , 1998 .

[39]  G. Kramer,et al.  An ab-initio study of D/H exchange between CD4 and the H-forms of zeolites FAU and MFI , 1995 .

[40]  Weiguo Song,et al.  In Situ NMR Investigations of Heterogeneous Catalysis with Samples Prepared under Standard Reaction Conditions. , 1998, Angewandte Chemie.

[41]  J. Nicholas,et al.  13C CHEMICAL SHIFT TENSOR OF THE ISOPROPYL CATION , 1996 .

[42]  B. Langner.  Reactions of methanol on zeolites with different pore structures , 1982 .

[43]  C. Catlow,et al.  SAPO-18 Catalysts and Their Broensted Acid Sites , 1994 .

[44]  J. F. Haw,et al.  Methylbenzene Chemistry on Zeolite HBeta: Multiple Insights into Methanol-to-Olefin Catalysis , 2002 .

[45]  J. Sauer,et al.  Ab initio molecular dynamics simulation of methanol interacting with acidic zeolites of different framework structure , 2000 .

[46]  Weiguo Song,et al.  Supramolecular origins of product selectivity for methanol-to-olefin catalysis on HSAPO-34. , 2001, Journal of the American Chemical Society.

[47]  J. F. Haw,et al.  Experimental considerations in variable-temperature solid-state nuclear magnetic resonance with cross polarization and magic-angle spinning , 1986 .

[48]  Weiguo Song,et al.  NMR and Theoretical Study of Acidity Probes on Sulfated Zirconia Catalysts , 2000 .

[49]  Teng Xu,et al.  A Solid Acid Catalyst at the Threshold of Superacid Strength: NMR, Calorimetry, and Density Functional Theory Studies of Silica-Supported Aluminum Chloride , 1997 .

[50]  Frerich J. Keil,et al.  Methanol-to-hydrocarbons: process technology , 1999 .

[51]  S. Blaszkowski,et al.  Activation of C-H and C-C Bonds by an Acidic Zeolite: A Density Functional Study , 1996 .

[52]  E. Munson,et al.  A report of a persistent allyl cation on H-ZSM-5 zeolite was due to propanal , 1994 .

[53]  Teng Xu,et al.  Cyclopentenyl Carbenium Ion Formation in Acidic Zeolites: An in situ NMR Study of Cyclic Precursors , 1994 .

[54]  T. Mole,et al.  Conversion of methanol to hydrocarbons over ZSM-5 zeolite: An examination of the role of aromatic hydrocarbons using 13carbon- and deuterium-labeled feeds , 1983 .

[55]  J. A. Speed,et al.  Reactions of propene on zeolite HY catalyst studied by in situ variable-temperature solid-state nuclear magnetic resonance spectroscopy , 1989 .