FIELD: organic chemistry, chemical technology. SUBSTANCE: invention describes method of epoxidation of C2-C4-olefins involving: (a) reaction of secondary C3-C4-alcohol and molecular oxygen in liquid phase to yield oxidative mixture consisting of secondary C3-C4,-alcohol, C1-C4- -ketone corresponding to secondary C3-C4-alcohol and hydrogen peroxide; (b) isolation of practically total amount of C1-C4- -ketone from oxidative mixture and preparing the flow containing concentrated hydrogen peroxide and involving secondary C3-C4-alcohol, hydrogen peroxide and 1 weight % of C3-C4-ketone, not less; (c) reaction of the flow containing concentrated hydrogen peroxide with C2-C4-olefin in the presence of titanium silicate as a catalyst. At the stage (c) the flow containing concentrated hydrogen peroxide interacts with C2-C4-olefin in the presence of methanol as a diluting agent to yield the epoxidation reaction mixture involving C2-C4-epoxide corresponding to C2-C4-olefin, water and secondary C3-C4-alcohol and then stage (d) is carried out additionally that involves isolation of practically total amount of C2-C4-epoxide from the epoxidation reaction mixture to form the first flow of crude alcohol involving water, secondary C3-C4,-alcohol and less 1 weight % of C2-C4-epoxide; (e) isolation of practically total amount of methanol from the first flow of crude alcohol to form the second flow of crude alcohol involving water, secondary C3-C4-alcohol and less 1 weight % of methanol; (f) recirculation of at least part of methanol isolated at stage (e) for using as a diluting agent at the stage (c). EFFECT: improved method of epoxidation, enhanced selectivity of process. 18 cl, 1 dwg, 4 ex
