Direct oxidation of n-heptane to ester over modified sulfated SnO2 catalysts under mild conditions.

The direct oxidation of n-heptane to ester using air as the oxidant under mild conditions assisted by sulfated tin oxide (SO(4)(2-)/SnO(2)) and Co modified sulfated tin oxide (SO(4)(2-)/SnO(2)-Co(2)O(3)) prepared by chemical co-precipitation method and characterized by means of SEM, XRD, FT-IR and XPS techniques was studied. From the results it was found that the catalytic activity of SO(4)(2-)/SnO(2)-Co(2)O(3) is higher than that of SO(4)(2-)/SnO(2) in this target reaction, and two asymmetric esters: diisobutyl phthalate and cyclohexylmethyl tridecyl oxalate that have not been reported in the directly oxidation of n-heptane by traditional method have been obtained. The possible mechanism was also discussed.