Guidelines for Mastering the Properties of Molecular Sieves: Relationship between the Physicochemical Properties of Zeolitic Systems and Their Low Dimensionality(221 NATO Science Series B:)

Low dimensionality is a multifarious concept which applies to very diversified materials. Thus, examples of low-dimensional systems are structures with one or several layers, single lines or patterns of lines, and small clusters isolated or dispersed in solid systems. Such low­ dimensional features can be produced in a wide variety of materials systems with a broad spectrum of scientific and practical interests. These features, in turn, induce specific properties and, particularly, specific transport properties. In the case of zeolites, low dimensionality appears in the network of small-diameter pores of molecular size, extending in one, two or three di­ mensions, that these solids exhibit as a characteristic feature and which explains the term of "molecular sieves" currently used to name these ma­ terials. Indeed, a large number of industrial processes for separation of gases and liquids, and for catalysis are based upon the use of this low­ dimensional feature in zeolites. For instance, zeolites constitute the first class of catalysts employed allover the world. Because of the peculiarity and flexibility of their structure (and composition), zeolites can be adapted to suit many specific and diversified applications. For this reason, zeolites are presently the object of a large and fast-growing interest among chemists and chemical engineers.

Table of Contents:
Orientation of Chemical Properties by Direct Synthesis of Molecular Sieves.- Effects of substitution in SAPO-n frameworks on their properties as acid catalysts.- Zeolite synthesis and crystal tailoring.- New mobilizing and templating agents in the synthesis of crystalline microporous solids.- A 13C- and 129Xe- NMR study of the role of the tetraalkylammonium cations in the synthesis of high-silica zeolites.- Promoter effects on phase growth in aluminophosphate and silicalumino-phosphate gel systems.- Characterisation of Structural and Physicochemical Properties of Zeolitic Systems.- Recent advances in techniques for characterizing zeolite structures.- Recent progress in the understanding of chemical properties of zeolites.- The determination of (Si, Al) distribution in zeolites.- Solid state ion exchange-Phenomenon and mechanism.- Static and Dynamic Parameters in Adsorption and Catalysis in Zeolites.- Temperature dependence of the mobility of molecules sorbed in type A zeolites.- NMR-studies of molecular motion of hydrocarbons in different faujasites.- Zeolitic heteropolyoxometalates.- Localized and Overall Properties Related to the Nature and Structural Organization of the Framework Atoms.- On lattice dynamics, stability and acidity of zeolites.- Confinement effects in sorption and catalysis by zeolites.- Cooperative and localised effects in catalysis over zeolites.- Long range versus short range interactions in zeolites.- Acid function in zeolites: recent progress.- Directing activity and selectivity of large pore acid zeolites through the control of their physicochemical properties.- Orientation of the Path of Reactions (Catalysis, Adsorption) By Chemical or other Geometric or Non Geometric Effects.- Is the shape selectivity always responsible for the orientation of,the reaction path in zeolite catalysis?.- Factors influencing the selectivity of hydrocracking in zeolites.- Hydroisomerization and hydrocracking of alkanes. 6. Influence of the pore structure on the selectivity of Pt-zeolite.- The structural elements of faujasite and their impact on cracking selectivity.- Overview of the Workshop.- Relationship between the physicochemical properties of zeolitic systems and their low dimensionality.- Discussion Reports.- Orientations of Chemical Properties by direct synthesis of molecular sieves.- Characterisation of structural and physico-chemical properties of zeolitic systems.- Static and dynamic parameters in adsorption and catalysis in zeolites.- Localized and overall properties related to the nature and the structural organization of the framework atoms.- Orientation of the path of reactions (catalysis, adsorption) by chemical or other geometric or non geometric effects.- Participants.