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

From Microporous to Mesoporous Molecular-Sieve Materials and Their Use in Catalysis

3.2.3. Hydroformylation 2467 3.2.4. Dimerization 2468 3.2.5. Oxidative Cleavage and Ozonolysis 2469 3.2.6. Metathesis 2470 4. Terpenes 2472 4.1. Pinene 2472 4.1.1. Isomerization: R-Pinene 2472 4.1.2. Epoxidation of R-Pinene 2475 4.1.3. Isomerization of R-Pinene Oxide 2477 4.1.4. Hydration of R-Pinene: R-Terpineol 2478 4.1.5. Dehydroisomerization 2479 4.2. Limonene 2480 4.2.1. Isomerization 2480 4.2.2. Epoxidation: Limonene Oxide 2480 4.2.3. Isomerization of Limonene Oxide 2481 4.2.4. Dehydroisomerization of Limonene and Terpenes To Produce Cymene 2481

Chemical Routes for the Transformation of Biomass into Chemicals

Ordered mesoporous materials in catalysis

A surface science perspective on TiO2 photocatalysis

In the last few years there has been a rapid growth in governmental funding and research activities worldwide for CO2 capture, storage and utilization (CSU), due to increasing awareness of the link between CO2 accumulation in the atmosphere and global warming. Among the various technologies and processes that have been developed and are emerging for CSU of CO2, solid CO2-adsorbents are widely applied. In this review, these solid CO2-adsorbents are classified into three types according to their sorption/desorption temperatures: low-, intermediate- and high-temperature adsorbents with temperatures ranging from below 200 °C, between 200–400 °C and above 400 °C, respectively. For each type of solid CO2-adsorbent, the synthesis, interaction mechanism with CO2 and sorption performance, potential applications and problems are reviewed. In the last section, several representative CO2-sorption-enhanced catalytic reactions are discussed. It is expected that this review will not only summarize the main research activities in this area, but also find possible links between fundamental studies and industrial applications.

CO2 capture by solid adsorbents and their applications: current status and new trends

Transition-metal ions in aluminophosphate and silicoaluminophosphate molecular sieves: location, interaction with adsorbates and catalytic properties.

Mesoporous silica SBA-15 molecular sieve has been synthesized and incorporated with aluminum via three different postsynthesis procedures by reacting SBA-15 with AlCl3 in dry ethanol (route 1), wit...

Alumination and Ion Exchange of Mesoporous SBA-15 Molecular Sieves

Mesoporous silica molecular sieve SBA-15 has been synthesized and incorporated with variable amounts of titanium via incipient-wetness impregnation with titanium isopropoxide in ethanol followed by calcination. Characterization by powder X-ray diffraction, nitrogen adsorption, X-ray photoelectron, Raman, and diffuse reflectance ultraviolet spectroscopies has been carried out to understand the chemical nature of the titanium. The results suggest that titanium is present in two distinct chemical forms and that their relative amounts depend on the titanium loading. At low titanium loading of 1 atom % relative to silicon, the titanium ions are monatomically dispersed and the pore size of SBA-15 is not altered. This isolated titanium species reaches a maximum concentration around 6 atom % relative to silicon. At higher titanium loading, titanium dioxide (anatase) is also formed. The materials with significant titanium dioxide formation have reduced pore diameters, which suggests that the titanium dioxide exist...

Incorporation of Titanium into Mesoporous Silica Molecular Sieve SBA-15

Fourier Transform Electron Spin Resonance (M. Bowman) New Trends in Pulsed Electron Spin Resonance Methodology (A. Schweiger) Two-Dimensional Electron Spin Resonance (J. Gorcester, et al.) Pulsed ENDOR Spectroscopy in Solids (A. Grupp & M. Mehring) Developments in Electron Spin-Echo Modulation Analysis (L. Kevan) High-Frequency Pulsed Electron Spin Resonance (J. Allgeier, et al) Continuous-Wave Transient Electron Spin Resonance (K. McLauchlan) High-Frequency Continuous-Wave Electron Spin Resonance (Y. Lebedev) Electron Spin Resonance Imaging (S. Eaton & G. Eaton) Index.

Modern pulsed and continuous-wave electron spin resonance

Powder X-ray diffraction (XRD), 29Si magic-angle-spinning (MAS) NMR spectroscopy, and transmission electron microscopy (TEM) as well as N2 adsorption have been employed to study the formation of various mesophases that lead to the synthesis of cubic mesoporous MCM-48 molecular sieve. A typical synthesis is performed at 373 K, pH = 11.8 using tetraethyl orthosilicate as the silicon source and cetyltrimethylammonium bromide (CTAB) as the structure-directing agent with a molar gel composition of 1:0.23:0.55:112SiO2/Na2O/CTAB/H2O. XRD shows that a disordered tubular mesophase (H1) rapidly forms and then transforms to a layered phase (L1) upon heating at 373 K for 5−10 h. After the hydrothermal treatment continues for 72 h, the layered phase (L1) gradually transforms to a cubic MCM-48 mesophase (V), which is accompanied by a slight pH increase of about 0.2 units. Prolonged hydrothermal treatment for over 120 h results in further structural transformation from the cubic mesophase V to a second layered phase (L2...

Larry Kevan

Papers

Transition-metal ions in aluminophosphate and silicoaluminophosphate molecular sieves: location, interaction with adsorbates and catalytic properties.

Alumination and Ion Exchange of Mesoporous SBA-15 Molecular Sieves

Incorporation of Titanium into Mesoporous Silica Molecular Sieve SBA-15

Modern pulsed and continuous-wave electron spin resonance

A Reliable Synthesis of Cubic Mesoporous MCM-48 Molecular Sieve