The invention relates to use of trioxepan compounds of formula I with R1-3 being independently selected from substituted or unsubstituted hydrocarbyl groups in the process to make fuels with improved ignition properties. Preferably, R1 and R3 are selected from lower alkyl groups, such as methyl, ethyl, and isopropyl, while R2 is preferably selected from methyl, ethyl, isopropyl, isobutyl, amyl, isoamyl, cyclohexyl, CH3C(O)CH2—, C2H5OC(O)CH2—, HOC(CH3)2CH2—, and