The formation of zeolitic coatings and their properties, such as the t
hickness, continuity and orientation of the crystals, are related to t
he presence and macro-organization of a precursor phase. Based on this
view, preshaped zeolitic coatings can be prepared which may be either
active catalysts themselves or an inert thin membrane on an existing
catalyst. They can be applied in low pressure drop reactors, in adsorp
tion units, in catalytic distillation units and in integrated reaction
separation systems as zeolitic membranes, Coating preparation and par
ticular aspects of the performance of the zeolitic coatings in a membr
ane configuration, in selective catalytic conversion of NOx, as an ine
rt membrane on a catalyst phase, and model structured catalyst systems
are discussed. (C) 1998 Elsevier Science B.V. All rights reserved.