The present disclosure relates to a method of epoxidizing an olefin to form an epoxide, the method comprising contacting an alkene(C≤12) or aralkene(C≤12) with a titanium silica catalyst, a peroxide, a buffer, and one or more organic solvents in a reaction mixture, wherein the one or more organic solvents comprise a first organic solvent selected from: R1—OH  (I), R2—CN  (II), R3—C(O)—R4  (III) or R5—O—R6  (IV) wherein: R1 is alkyl(C≤12), aryl(C≤12), aralkyl(C≤12) or a substituted version of any of these groups; R2 is alkyl(C≤12), aryl(C≤12), aralkyl(C≤12) or a substituted version of any of these groups; R3 is hydrogen, alkyl(C≤6) or substituted alkyl(C≤6); and R4, R5, and R6 are each independently selected from alkyl(C≤12), aryl(C≤12), aralkyl(C≤12) or a substituted version of any of these groups, or are taken together are alkoxydiyl(C≤12), alkanediyl(C≤12), substituted alkoxydiyl(C≤12) or substituted alkanediyl(C≤12).