Synthesis, characterization and catalytic properties of microporous cobalt aluminosilicate (CoLTL) molecular sieves

Thermally stable divalent cobalt substituted microporous aluminosilicate (CoLTL) molecular sieves were synthesized and characterized. These studies revealed isomorphous substitution of divalent cobalt in tetrahedral framework of LTL structure. In addition, the typical blue color of CoLTL confirms the tetrahedral environment of divalent cobalt in the framework, and as a result the catalyst showed excellent activity for the oxidation of cyclohexane under mild reaction conditions. Furthermore, unlike the many other cobalt-based microporous (heterogeneous) catalysts reported so far, CoLTL does not show any dislodgement or segregation of cobalt upon calcination or any other post-synthesis treatments. In this study, the performance of CoLTL was also compared with cobalt-containing aluminophosphate and silicate molecular sieves having AFI and MF1 structures, respectively. © 2008 al-Farabi Kazakh National University.