maintained almost constant even when the molar ratio was increased above 0 0025 the synthesis yields of glycidol depending on the molar ratio of bmim no 3 as an ionic liquid catalyst to zn no 3 2 as a lewis acid metal salt were compared for this comparison glycidol was synthesized in the same manner as in example 1 except that the moles of bmim no 3 and zn no 3 2 were changed as shown in table 4 the results are shown in table 4 as can be seen from the results in table 4 the addition of zn no 3 2 was effective in increasing the yield of glycidol while inhibiting side reactions and the effect was maximized when zn no 3 2 was added in an amount of 0 2 moles per one mole of the catalyst bmim no 3 the synthesis yields of glycidol when metal salts other than the zinc salt were used as lewis acid metal salts were compared for this comparison glycidol was synthesized in the same manner as in example 1 except that other lewis acid metal salts were added to the catalyst bmim no 3 instead of zn no 3 2 the results are shown in table 5 as can be seen from the results in table 5 zncl 2 mgcl 2 alcl 3 were also observed to have similar effects to zn no 3 2 but sncl 4 failed to show a good yield of glycidol this phenomenon indicates that effects of.