Direct synthesis of Cu-containing Beta zeolite without template for selective oxidation of cyclohexane.

Cu-containing Beta zeolites (Cu-Beta) are straightforwardly synthesized in a one-pot method without template, where the crucial step is the co-hydrolysis/condensation of silica source and copper salt at the moderate acidic condition. In the solvent-free oxidation of cyclohexane with molecular oxygen (O₂), the best cyclohexane conversion result (9.7%) with a KA-oil (cyclohexanone and cyclohexanol) selectivity of 94.1% is obtained over Cu-Beta(100). Structure—activity relationship analysis indicates that the isolated tetrahedral framework Cu²⁺ species and chemisorption oxygen species in high concentration on the catalyst surface enhannce the catalic performance. In addition, the catalyst can be easily separated and still remain stable after recycling five times, providing new insights into catalysts design for the catalytic oxidation of cyclohexane to KA-oil. [ABSTRACT FROM AUTHOR]