Fernando Ramôa Ribeiro

Zeolite microporous solids : synthesis, structure, and reactivity

I. Synthesis.- Some thermodynamic and kinetic effects related to zeolite crystallization.- Organic and inorganic agents in the synthesis of molecular sieves.- Non-conventional crystalline microporous solids.- Molecular engineering of lamellar solids. I. Principles derived from the pillaring of smectite clays.- Molecular engineering of layered structures II. Synthetic approaches to some new pillared derivatives.- II. Characterization.- General overview of the characterization of zeolites.- Sorption of single gases and their binary mixtures in zeolites.- Frequency-response measurements of diffusion of sorbates in zeolites.- Diffraction Studies of zeolites.- Spectroscopic investigations of zeolite properties.- The impact of NMR spectroscopy in molecular sieve characterization I. Low Si/Al ratio materials.- The impact of NMR spectroscopy in molecular sieve characterization II. Investigations of highly siliceous systems.- III. Modification, Reactivity, and Catalytic Activity.- Modification of zeolites and new routes to ion-exchange.- Zeolite framework substitution reliable characterization methods.- Evaluation and tailoring of acid-base properties of zeolites Part 1.- Evaluation and tailoring of acid-base properties of zeolites Part 2.- Catalysis by exchanged cations and zeolite framework sites.- Zeolites in oil refining and petrochemistry.- Composition of the carbonaceous compounds responsible for zeolite deactivation. Modes of formation.- Deactivation of zeolites by coking. Prevention of deactivation and regeneration.- IV. Novel Developments and Vistas.- Molecular sieves with pore openings consisting of more than 12-T atoms.- Chemical bonding in zeolites.- Some aspects of molecular shape-selective catalysis with hydrocarbons in zeolites.- New applications of nonclassical molecular sieve catalysts.- Enzyme mimicking with zeolites.- Microporous materials in organic synthesis.- Concluding Remarks.- List of Participants.

Activity–acidity relationship in zeolite ZSM-5. Application of Brönsted-type equations

In this paper the relation between activity and acidity in a variety of ZSM-5 zeolite catalysts, with different Si/Al ratios and different protonic content, is analysed and a quantitative correlation is obtained. The acid site strength distribution was estimated using temperature-programmed desorption (TPD) of ammonia by applying a digital deconvolution method to the curves. These data were then correlated with experimental catalytic activity data for the same catalysts towards n-heptane cracking reaction, by means of a Bronsted-type equation similar to the ones used for homogeneous acid catalysis and already used for other zeolites. It can be noticed that the same types of equation that are used for homogeneous acid catalysis also hold for heterogeneous acid catalysis and that the activation energy for ammonia desorption can be used as acid-strength scale for the purpose of correlation with catalytic activity.

Hydroisomerization of n-hexane on platinum zeolites: I. Kinetic study of the reaction on platinum/Y-zeolite catalysts: Influence of the platinum content

Abstract The transformation of n -hexane has been carried out under hydrogen pressure on a series of platinum-stabilized Y-zeolites with platinum contents varying from 0 to 17.7 wt% (platinum area ranging from 0 to 10 m 2 g −1 ). The conventional bifunctional mechanism accounts for the change in the isomerization activity and selectivity with the platinum area and with various operating conditions (temperature, n -hexane and H 2 pressures, H 2 S and NH 3 poisoning). Moreover, the cracking mechanism shifts from a carbonium ion one on small platinum area catalysts to hydrogenolysis on large platinum area catalysts.

Acylation of phenol with acetic acid over a HZSM5 zeolite, reaction scheme

Abstract The scheme of the gas phase phenol acylation with acetic acid on a HZSM5 zeolite was established from the effect of contact time (hence of conversion) on the product distribution. Phenyl acetate and o -hydroxyacetophenone are primary products, O-acylation being much faster than C-acylation. At high conversion, part of the o -hydroxyacetophenone results from the acylation of phenol with phenyl acetate. The formation of p -hydroxyacetophenone which does not occur through phenol acylation involves the hydrolysis of p -acetoxyacetophenone selectively formed through the autoacylation of phenyl acetate. The ortho -selectivity of phenol acylation can be related to a pronounced stabilization of the transition state while the para -selectivity of phenyl acetate autoacylation could be due to a steric hindrance to the approach of the acetyl group in the ortho -position of phenyl acetate.

Sustainable strategies for the upgrading of natural gas : fundamentals, challenges, and opportunities

Preface. Section I. Lectures. Natural Gas: Fuel or Feedstock? J.R. Rostrup-Nielsen. Molecular Chemistry of Alkane Activation F. Solymosi. Economics of Alkane Conversion J.-P. Lange. Theoretical Basis of the Activation of Light Alkanes M. Witko et al. Surface Organometallic Chemistry of Tantalum: Application to the Metathesis of Alkanes Catalyzed by a Tantalum Hydride Supported on Silica J. Thivolle-Cazat et al. The Challenges in Converting Remote Natural Gas to Valuable Products D. Trimm. Alternative Routes To Synfuel From Natural Gas D. Trimm. New Technologies for Light Alkane Upgrading. J. Gascon et al. Fundamentals of the Fischer-Tropsch Synthesis A.L. Lapidus. Reactor Technology for Syngas and Hydrogen E.H. Stitt. Engineering Alkanes to Olefins and Higher Value Chemicals D. Sanfilippo et al. Membrane Reactors For The Fischer-Tropsch Synthesis A.A. Khassin. Sources of methane for sustainable development V.N. Parmon. Section II. Communications. CO2 Separation by Membranes in Natural Gas Processing G. Clarizia, E. Drioli. Structural and Textural Properties of MCM-41 Mesoporous Molecular Sieves Containing Nb, V, Mo - Alternative Catalysts for Hydrocarbons Oxidation I. Nowak et al. Acidic and Catalytic Properties of Dealuminated BEA Zeolites J. P. Marques et al. Influence of the H-Ferrierite Sample on the Selectivity of Skeletal n-Butene Isomerization B. De Menorval et al. Study on the Lattice Defects in the Mixed Oxides of Neodymium and Alkaline Earth Elements and their Role on the Oxidative Coupling of Methane D. Filkova. Molecular Mechanism of the Methane Dissociation on the Vanadium Oxides Clusters. DFT Calculations W. Piskorz, E. Broclawik. Acidity, Activity and Micro-Kinetics Studies in a H-ZSM5 P. Borges et al. Microkinetic Model for Propane Activation over H-ZSM5 P. Borges et al. 13C MAS NMR Mechanistic Study of the Initial Stages of Propane Activation over Zn/H-MFI Catalyst Yu.G. Kolyagin et al. Dehydrogeflationof Propane over Chromium-Based Catalysts P. Michorczyk et al. Catalytic Oxidation of Methanol to Formaldehyde A. H. Yilmaz et al. Conversion of Gas Condensate over Metal-Containing MFI Catalysts A.G. Popov et al. Coke Formation on Alumina and Alumina Supported Platinum Catalysts Z. Sarbak. Activation Studies of the Cs-Doped Cu/ZnO Catalyst for the Higher Alcohol Synthesis L. Nowicki et al. Development of high temperature catalytic reactors for oxidative conversion of natural gas S. Cimino et al. The Effect of Process Conditions on Product Formation in Fischer-Tropsch Synthesis Sh.S. Itkulova. Mathematical Modeling of Steam Reforming Tubes with Shaped Particles A.P. Kagyrmanova et al. Application of NMR Microimaging for the Investigation of the Heterogeneous Catalytic Reactions Inside Catalyst Pellets and Fixed Catalyst Bed A.A. Lysova et al. Section III. Conclusions. Natural Gas as Feedstock J.C. Vedrine. Sustainable Strategies for the Upgrading of Natural Gas Eric G. Derouane. Participants. Subject Index. Author Index.

Principles and methods for accelerated catalyst design and testing

Table of Contents. Preface. Section 1: Lectures. Challenges and Strategies for the Implementation of Combinatorial Methods and High Throughput Testing in Heterogeneous Catalysis E.G. Derouane. Problems and Challenges About Accelerated Testing of the Catalytic Activity of Catalysts L. Petrov. Mass Transfer Limitations: A Bottleneck for High Throughput Screening in Multiphase Catalysis? C. de Bellefon. Combinatorial Methodology and its Experimental Validation by Parallel Synthesis, Testing And Characterization of Solid Catalytic Materials M. Baerns, et al. The Combinatorial Approach for Heterogeneous Catalysis: a Challenge for Academic Research D. Farrusseng, et al. An Evolutionary Strategy for the Design and Evaluation of High-Throughput Experiments D. Wolf. Organometallic Combinatorial Chemistry O. Lavastre, et al. Application of Genetic Algorithms to the Development and Optimisation of Light Paraffin Isomerisation Catalysts A. Corma, et al. Serial and Parallel Ways to Enhance and Accelerate Catalyst Testing P.P. Pescarmona, T. Maschmeyer. Rapid Catalyst Testing in The Boreskov Institute of Catalysis N.N. Bobrov, V.N. Parmon. Analysis and Modelling of Multi-Site Acid Catalysts F. Lemos, et al. Combinatorial and High Throughput Approaches in Heterogeneous Catalysis: Reality or Illusion C. Nacchace. Ultrafast Gas Chromatography V.N. Sidelnikov, et al. Section 2: Communications. Parallel Catalytic Synthesis of Phosphines and Related Ligands L. Xu, et al. Mixed Oxide Catalysts for Oxidation of Propane to Acrylic Acid: a Method for the Preparation of Realistic Catalyst Libraries and Their Quantitative Assessment L. Chen, et al. High Throughput Testing of Catalysts for the Hydrogenation of Carbon Monoxide to Ethanol O.M. Wilkin, et al. Transformation of Short Chain n-Alkanes on Dodecatungstophosphoric Acid and its Cesium Salts Ph. Bichon, et al. Complete Catalytic Oxidation of Methane and Ethane over Supported Platinum, Palladium and Manganese Oxide Catalysts G.C. Bond, et al. Rational Catalyst Selection and Optimization Versus Combinatorial? Case Study: Hydrogenolysys of Ethyl Laurate to 1-Dodecanol on Ru(Rh)-Sn(Re)/g-Al2O3 Catalysts S. Gobolos, et al. Studies on the Ultrasonic Enhancement of the Catalytic Activity in the Hydrogenation of Citral J.-P. Mikkola, et al. Future Trends in the Worldwide Oil Refining Industry R.P. Silvy. Catalyst Preparation and Testing for Catalytic Combustion of Chloromethanes S. Atalay, et al. Impulse Oscillation Model for Accelerated Catalyst Design M.A. Borowiak. Catalytic Oxidation of BINAP on (BINAp)Rh(co)cl K.A. Bunten, et al. Catalysts for Wastewater Treatment I. Castelo-Branco, et al. The Routes of Deep Oxidation Reactions on the CuCl2/Al2O3 Catalysts in the Ethylene Oxychlorination Process M.R. Flid, et al. The Catalytic Dehydrochlorination of Polychloroethanes in a Gas Phase M.A. Trushechkina, et al. The Bimetallic Co-Containing Supported on Alumina Catalysts in the Synthesis on the Base of Carbon Oxides Sh.S. Itkulova. Theoretical Investigations of Mo Catalysts in Olefin Metathesis J. Handzlik, J. Ogonowski. Differential Thermal Analysis and Thermal Gravimetry as Fast Methods to Test Catalytic Oxidation of Carbon Particulates Z. Sarbak, K. Surma. Aniline Methylation over Modified Micro- and Mesoporous Catalysts O.A. Ponomoreva, et al. Live Catalysis C. Lobato da Silva, et al. Section 3: Workshop. Accelerated Catalyst Preparation an

Hydroisomerization of n-hexane on platinum zeolites: II. Comparison between the reaction mechanisms on platinum/Y-zeolite and on platinum/mordenite

Abstract The transformation of n-hexane was carried out under hydrogen pressure, on platinum/mordenite and platinum/Y-zeolite with platinum areas ranging from 0 to 10–15 m2 g−1. For both series, as can be expected from the conventional bifunctional process, the isomerization activity is proportional to the platinum area for small platinum areas and almost independent of it for large platinum areas. However, the primary products of n-hexane and 3-methylpentane isomerization are notably different: the selectivity of platinum/Y-zeolite with a platinum area ≥0.5 m2 g−1 is typical of a bifunctional reaction with, as limiting step, the skeletal isomerization of intermediate olefins; that of platinum/mordenite, even with a platinum area equal to 15 m2 g−1, remains intermediate between those of platinum-free zeolites and large platinum area Y catalysts. These differences are clearly related to the higher activity of platinum/mordenite, to its lower hydrogenation activity as well as to diffusional limitations in the practically unidimensional porous structure of mordenite.

Phenol acylation: unexpected improvement of the selectivity to o-hydroxyacetophenone by passivation of the external acid sites of HZSM5

The acylation of phenol by acetic acid on zeolite ZSM5 is unexpectedly oriented towards o-hydroxyacetophenone by dealumination of the outer surface of the crystallites, which can be ascribed to the existence of two different pathways for the formation of o- and p-hydroxyacetophenones.

Textural characteristics of Y and ZSM-20 zeolites determined by nitrogen adsorptions

The adsorption of nitrogen at 77 K on Y and ZSM-20 zeolites has been studied. The isotherms have been analyzed by use of the α s method and the Dublinin-Radushkevich equation, and the microporous capacities, sizes of pores, and the external areas were evaluated. The mechanisms involved in the microporous filling of these solids, which have pores of uniform size and shape, are discussed.

Homogeneous Ziegler–Natta Polymerisation: a Kinetic Approach1. Steady-State Kinetics

This series of papers describes a kinetic approach to the study of homogeneous Ziegler-Natta polymerisation of light olefins. Several kinetic rate laws, based on models proposed in the literature, are developed and discussed, and fitted to several sets of experimental results. In this first part, the questions that are raised in stationary state conditions are examined.