Cation-exchanged fluorotetrasilicic mica (Mn+–TSM; Mn+= Mn2+, Cr3+, Co2+ and Cu2+)-catalysed oxidation of alkanes with tert-butyl hydroperoxide

Abstract

Oxidation of alkanes such as cyclohexane 1, cyclooctane 4, cyclododecane 7, adamantane 10, octane 14, methylcyclohexane 18 and 2,5-dimethylhexane 23 with 70% aqueous tert-butyl hydroperoxide has been investigated in benzene in the presence of cation-exchanged fluorotetrasilicic mica (Mnⁿ⁺–TSM; Mⁿ⁺= Mn²⁺, Cr³⁺, Co²⁺ and Cu²⁺) and molecular sieves 4 Å. Compound 1 was oxidised to cyclohexanone 2(a major product) and cyclohexanol 3 in 9.7–13.4% GLC yield with turnover numbers 154–205, where Mn²⁺–TSM gave the highest turnover number. Similarly, other alkanes 4, 7, 10, 14, 18 and 23 were oxidised mainly to the corresponding ketones in the presence of Mn²⁺–TSM with a turnover number up to 435. It was confirmed in the cyclohexane oxidation that Mn²⁺–TSM was regenerated and reused. Compounds 1, 4 and 10 were shape-selectively oxidised in teh presence of Cr³⁺–TSM.