The invention relates to a process for the manufacture of a 1,2-epoxide by catalytic oxidation of a terminal olefin with hydrogen peroxide wherein the catalytic oxidation is performed in a biphasic system comprising an organic phase and an aqueous reaction medium, wherein a water-soluble manganese complex is used as oxidation catalyst, wherein a terminal olefin is used with a solubility at 20° C. of at least 0.01 to 100 g in 1 liter water, and wherein the molar ratio of terminal olefin to hydrogen peroxide is in the range of from 1:0.1 to 1:2.