Microporous acidic oxide with catalytic properties itq - 18

摘要

The invention relates to a microporous crystalline material with a characteristic X-ray diffractogram, comprised of tetrahedra of oxygen and a metal (T?+4 and T+3¿) with possibility of introducing superficial acidity produced by substitution in the network of certain cations T+4 (normally Si+4) by cations T+3 (normally Al+3), thereby causing a deficiency in the structural charge which can be compensated by protons, Brönsted acidity, and/or cations with high charge-radius ratio, Lewis acidity. The preparation method is based on the modification of the laminar structure of a mixed oxide (normally SiO¿2?, Al2O3) which is synthesized from a gel having been treated in controlled hydrothermal conditions and intercalating between its sheets organic molecules which have a proton acceptor group and a long hydrocarbon chain. The sheets of the intercalated material are quite separated between each other due to the presence of organic chains between the sheets. The swollen material is then treated in order to separate and disperse the sheets. The final washing and subsequent calcination result in a microporous material with large external surface.