This article provides an overview of nanoporous materials with MWW (Mobil twenty two) topology. It covers aspects of the synthesis of the MWW precursor and the tridimensional zeolite MCM-22 (Mobil Composition of Matter number 22) as well as their physicochemical properties, such as the Si/Al molar ratio, acidity, and morphology. In addition, it discusses the use of directing agents (SDAs) to obtain the different MWW-type materials reported so far. The traditional post-synthesis modifications to obtain MWW-type materials with hierarchical architectures, such as expanded, swelling, pillaring, and delaminating structures, are shown together with recent routes to obtain materials with more open structures. New routes for the direct synthesis of MWW-type materials with hierarchical pore architecture are also covered.
A new route to obtain pillared, disordered or desilicated MWW-type zeolites was developed assisted by quaternary ammonium surfactants with different hydrocarbon tail size acting as swelling agents (C12TA +, C16TA +, C18TA +). Effect of surfactant concentration and swelling conditions were determinant to obtain MWW-type zeolites with different lamellar organization and spatial distribution of individual zeolitic layers. Specifically, soft swelling at 25 °C preserved layer structure instead of aggressive processes at 80 °C that favored desilication, damaging the layers structure in case of C12TA + and C16TA + and C18TA +. It was proved that surfactant size combining with swelling and pillaring procedure influenced on physico-chemical and morphological nature of MWW-type materials. The obtained derivative MWW zeolites with different morphology, order and acessibility levels were firstly evaluated by catalitic dehydration fructose to 5hydroxymethylfurfural showing, superior activity compared to commercial zeolite catalyst.
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