The direct oxidation of n-heptane to ester using air as the oxidant under mild conditions assisted by sulfated tin oxide (SO42-/SnO2) and Co modified sulfated tin oxide (SO42- /SnO2-Co2O3) 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 SO42-/SnO2-Co2O3 is higher than that Of SO42-/SnO2 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. (c) 2007 Elsevier B.V. All rights reserved.