Synthesis and characterization of Al-MSU-S mesoporous and meso-microporous molecular sieves and their catalytic performance

Al-MSU-S mesoporous molecular sieve (Al-MSU-S(me)) with high hydrothermal stability and acidity was reported recently. In this work, the Al-MSU-S(me) and the Al-NISU-S meso-microporous molecular sieve (Al-NISU-S(me-mi)) were prepared by the assembly of protozeotitic nanoclusters. When the Al content in Al-MSU-S was 2.5 % similar to 20 % and 25 % similar to 33.3 % respectively, the corresponding hexagonal mesoporous and meso-microporous structure was obtained. Three IR vibrational bands were observed in the range of 560 - 690 cm(-1), being comparable to microporous faujusite. The tetrahedral coordinated aluminum was found in all the Al-MSU-S molecular sieves, indicating that all the aluminum had entered Al-MSU-S framework. Both Al-MSU-S(me) and Al-MSU-S(me-mi) possessed medium and stronger acid sites. The acid amount of Al-MSU-S(me) increased as Al content decreased, and the acid amount of Al-MSU-S(me-mi) was much more than that of Al-MSU-S(me), and the acid strength of Al-MSU-S(me-mi) was much stronger than that of Al-MSUS(me). The catalytic activity of Al-MSU-S in H+ form was measured by diisopropylbenzene(DIPB) cracking reaction at different temperatures and pressure. Under the pressure of 0.1. MPa the Al-MSU-S ( me-mi) had higher activity than the Al-MSU-S(me), while the catalytic activity of Al-NISU-S(me) increased steadily as Al content decreased