Nomenclature, molecular sieve materials

There is no systematic nomenclature developed for molecular sieve materials. The discoverer of a synthehc species based on a characteristic X-ray powder diffraction pattern and chemical composihon typicaUy assigns trivial symbols. The early syn-thehc materials discovered by Milton, Breck and coworkers at Uruon Carbide used the modem Lahn alphabet, for example, zeoHtes A, B, X, Y, L. The use of the Greek alphabet was inihated by Mobil and Union Carbide with the zeoHtes alpha, beta, omega. Many of the synthetic zeoHtes which have the structural topology of mineral zeoHte species were assigned the name of the mineral, for example, syn-thehc mordenite, chabazite, erionite and offretite.The molecular sieve Hterature is replete with acronyms ZSM-5, -11, ZK-4 (Mobil), EU-1, FU-1, NU-1 (ICI), LZ-210, AlPO, SAPO, MeAPO, etc. (Union Carbide, UOP) and ECR-1 (Exxon). The one pubHcaHon on nomenclature by lUPAC in 1979 is Hmited to the then-known zeoHte-type materials [3]. 

Based on the lUPAC nomenclature, microporous molecular sieves have pores with dimensions up to 2.0 nm in dimension. The mesopore dimension is between 2.0 and 50 nm, while macropores exhibit pores larger than 50 nm. Shown in Fig. 2 are the pore size and schematic structure of several zeolites, zeotypes, and mesoporous molecular sieves. Evidently, a large number of different zeolite or zeotype structures and mesoporous materials are available from which the optimum one for the given application can be selected. 

The number of cases where adsorption microcalorimetry has been successfully applied to this end has increased in recent years, especially in the field of determination of the acidic function of molecular sieves, and extensive reviews of the systems investigated using this methodology have been published [2,5-18]. In particular, a review has been written [19] summarizing some of the most recently pubUshed results concerning the appUcations of microcalorimetry to the study of the acid/base sites of zeoUtes and meso-porous materials. The efficiency of thermal analysis techniques for the characterization of the acid/base strength of zeoUte materials is discussed, as weU as their ability to provide information consistent with catalytic data [19]. The reader is referred to the Atlas of Zeolite Structures [20] for nomenclature used throughout the text. 

Molecular sieves and other porous materials based on inorganic aluminosilicates, aluminophosphates and related frameworks can be prepared with pores of different diameters, [10,100] and are used both in large scale industrial applications as well as in the laboratory [101]. However, these are not the subjects of this book, although they have been (and are) important in the development of theory and nomenclature for 3D-nets [102,103]. 

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