Synthesis of fatty ketoesters by tandem epoxidation–rearrangement with heterogeneous catalysis†
Unsaturated fatty esters can be easily transformed into ketoesters through a two-step process. The highly efficient epoxidation is carried out with tert-butyl hydroperoxide (TBHP) in α,α,α-trifluorotoluene (TFT) using a Ti–silica heterogeneous catalyst. The formed epoxide is easily rearranged by a heterogeneous Brønsted acid, with Nafion–silica SAC13 as the most efficient one. Both reactions can be combined in a tandem process, with separation of the Ti–silica catalyst by filtration from the reaction medium and addition of the second acid catalyst to perform the second reaction. Each catalyst is separated individually and can be reused, with or without re-activation, under the same conditions to maximize the productivity.