Mesoporous molecular sieves, used as catalysts and adsorbents, have aluminum in pore walls and are produced from aqueous silicic acid solution by hydrothermal crystallization in presence of template and calcination

摘要

In mesoporous molecular sieves (I) containing aluminum (Al), Al is contained in the pore walls in homogeneous distribution, such that part of the Al is in silicon (Si) lattice positions in an Al:Si ratio of 1:(1-100), the pore wall thickness is 3-6 nm and the pore size is 2-30 nm. An Independent claim is also included for producing (I) by heating a precursor containing template to 400-600 degrees C until organic constituents are completely decomposed, in which the precursor is prepared from an unstable aqueous silicic acid solution containing 0.6-18 wt.% SiO2, which has pH 1.5-3.5 and contains condensed silicate anionic and reactive silanol groups, aged for 5 minutes to 3 days at 10-50 degrees C and reacted with an aqueous solution of Al oxo-hydroxy-cations with a OH/Al ratio of 2.0-2.5 and pH 3-6, in which reaction and then crystallization are carried out for 10 hours to 20 days at 20-180 degrees C in the presence of structure-forming organic compounds.