Patent ID: 8134018

Claim:
A process for epoxidizing an olefin comprising (a) reacting an olefin with hydrogen peroxide in the presence of methanol as solvent in at least two reaction stages to obtain a mixture (M-a) comprising olefin oxide, unreacted olefin, methanol, and water, wherein said olefin oxide is separated by distillation between said at least two reaction stages; (b) separating unreacted olefin from said mixture (M-a) by distillation to obtain a mixture (M-bi) comprising at least 80 weight % of olefin and a mixture (M-bii) comprising methanol, water, and at least 7 weight % of olefin oxide; (c) separating olefin oxide from said mixture (M-bii) in at least one distillation stage to obtain a mixture (M-ci) comprising at least 99 weight % of olefin oxide and a mixture (M-cii) comprising water and at least 55 weight % of methanol; and (d) separating methanol from said mixture (M-cii) in at least one distillation stage to obtain a mixture (M-di) comprising at least 85 weight % of methanol and up to 10 weight % of water and a mixture (M-dii) comprising at least 90 weight % of water; wherein a vapor top stream (Td) is obtained from at least one distillation column used in (d) and is used to operate at least partially at least one vaporizer used in at least one distillation column used in at least one of (a), (b) and (c), and wherein said vapor top stream (Td) comprises at least 85 weight % methanol.