SHUTDOWN METHOD FOR A PROCESS FOR PREPARING AN OLEFIN OXIDE

In a first aspect, the present invention relates to a shutdown method for a process for preparing an olefin oxide comprising a normal run stage, wherein the normal run stage comprises providing olefin, hydrogen peroxide and organic solvent into an epoxidation zone comprising an heterogeneous epoxidation catalyst, so that a reaction mixture comprising olefin, hydrogen peroxide and organic solvent is formed and subjecting the reaction mixture to epoxidation reaction conditions in the epoxidation zone, thereby obtaining a mixture comprising olefin oxide and organic solvent; wherein the shutdown method comprises (a) providing olefin and organic solvent for a period of time t1 to the epoxidation zone, so that a mixture is formed, which is essentially free of hydrogen peroxide; (b) contacting the mixture from (a) over t1 under epoxidation reaction conditions in the epoxidation zone with the heterogeneous epoxidation catalyst; (c) removing during t1 an effluent stream from the epoxidation zone, the effluent stream comprising olefin and organic solvent. In a second aspect, the present invention relates to a process for preparing an olefin oxide comprising a normal run stage and a shutdown stage, wherein the normal run stage comprises (A) providing olefin, hydrogen peroxide, water and organic solvent into an epoxidation zone comprising an heterogeneous epoxidation catalyst, so that a reaction mixture comprising olefin, hydrogen peroxide, water and organic solvent is formed; (B) subjecting the reaction mixture from (I) to epoxidation reaction conditions in the epoxidation zone, thereby obtaining a mixture comprising olefin oxide, water and organic solvent; (C) removing an effluent stream from the epoxidation zone, comprising olefin oxide, water and organic solvent; wherein the shutdown stage comprises steps (a), (b) and (c) as described with respect to the first aspect. Dans un premier aspect, la présente invention concerne un procédé d'extinction pour un procédé de préparation d'un oxyde d'oléfine comprenant une étape de fonctionnement normal, l'étape de fonctionnement normal comprenant l'introduction d'une oléfine, du peroxyde d'hydrogène et du solvant organique dans une zone d'époxydation comprenant un catalyseur d'époxydation hétérogène, de façon à former un mélange réactionnel comprenant une oléfine, du peroxyde d'hydrogène et un solvant organique et la soumission du mélange réactionnel à des conditions de réaction d'époxydation dans la zone d'époxydation, ce q