Fundamentals of micelle templating

06-0-01 - The effect of stoichiometry and synthesis conditions on the properties of mesoporous M41S family silicates 

ExxonMobil Research and Engineering, Annandale, USA wieslawJ roth email.mobil.com, James c yartuli email. mobil. com 

Basic quantitative relationships and trends governing the formation of the M41S mesoporous molecular sieves MCM-41 and MCM-48 are presented. The syntheses with hydroxide/surfactant molar ratio close to unity afforded high quality MCM-41 and proved particularly suitable for quantifying the effects of synthesis mixture composition and synthesis conditions upon the nature and properties of the mesoporous products. Increasing temperature and duration of crystallization resulted in unit cell expansion and a more robust silica framework. Syntheses with silica to surfactant molar ratio equal to 5 1 and higher gave MCM-41 while MCM-48 was observed at lower (3.5 1) ratios. 

MPIfur Kohlenforschung, 45470 Mulheim/Ruhr, marlow mpi-muelheim.mpg.de, Germany 

06-0-03 - Hierarchically mesostructured zeolitic materials with the MFI structure 

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Transition-metal nanopartides are of fundamental interest and technological importance because of their applications to catalysis [22,104-107]. Synthetic routes to metal nanopartides include evaporation and condensation, and chemical or electrochemical reduction of metal salts in the presence of stabilizers [104,105,108-110]. The purpose of the stabilizers, which include polymers, ligands, and surfactants, is to control particle size and prevent agglomeration. However, stabilizers also passivate cluster surfaces. For some applications, such as catalysis, it is desirable to prepare small, stable, but not-fully-passivated, particles so that substrates can access the encapsulated clusters. Another promising method for preparing clusters and colloids involves the use of templates, such as reverse micelles [111,112] and porous membranes [106,113,114]. However, even this approach results in at least partial passivation and mass transfer limitations unless the template is removed. Unfortunately, removal of the template may re-... 

To use templates or envelopes as a controlled reaction space was developed in the early 1980s, such as the use of inverse micelle technique (4). Another fundamental idea is to use the atomic periodicity of surfactant molecules by using them as surface ligands for sequential addition of anions and cations under the concept of semiconductive compounds like CdSe as a living polymer (3). 

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