PROCESS FOR REGENERATION OF AN EPOXIDATION REACTOR

The present invention relates in a first aspect to a process for the regeneration of an epoxidation reactor, the epoxidation reactor having been used in a method for the preparation of an olefin oxide comprising: (i) providing an organic solvent, an olefin, an epoxidation agent and water to the reactor, which comprises an heterogeneous epoxidation catalyst in an epoxidation zone, so that a reaction mixture comprising olefin, hydrogen peroxide, water and organic solvent is formed; (ii) subjecting the mixture of (i) in the reactor's epoxidation zone to epoxidation conditions in the presence of the catalyst, thereby obtaining a mixture comprising water, the organic solvent and olefin oxide; (iii) removing the mixture comprising water, the organic solvent and olefin oxide obtained in (ii) from the reactor; whereby a precipitate is deposited in the reactor; said process for the regeneration comprising: (a) stopping providing organic solvent, olefin, epoxidation agent and water to the reactor; (b) introducing a liquid aqueous system into the reactor, wherein the liquid aqueous system comprises a chelating agent, which comprises diphosphonic acid of formula (I) (OH)2(O=)P-CR1R2-P(=O)(OH)2 (I), wherein R1 and R2 are independently selected from the group consisting of hydrogen atom, hydroxyl group and C1 to C5 alkyl group, wherein R1 is preferably a hydroxyl group and R2 is preferably a methyl group (1-hydroxy ethylidene-1,1-diphosphonic acid, HEDP). A second aspect of the invention is related to a combined process for preparation of an olefin oxide comprising a preparation stage and a stage of regeneration of the epoxidation reactor, the preparation stage comprising steps (i), (ii) and (iii), whereby a precipitate is deposited in the reactor; the regeneration stage comprising steps (a) and (b). La présente invention concerne, dans un premier aspect, un procédé de régénération d'un réacteur d'époxydation, le réacteur d'époxydation ayant été utilisé dans un procédé de préparation d'un oxyde d'oléfine comprenant les étapes consistant à : (i) fournir un solvant organique, une oléfine, un agent d'époxydation et de l'eau au réacteur, qui comprend un catalyseur d'époxydation hétérogène dans une zone d'époxydation, de telle sorte qu'un mélange réactionnel comprenant une oléfine, du peroxyde d'hydrogène, de l'eau et un solvant organique est formé ; (ii) soumettre le mélange de (i) dans la zone d'époxydation du réacteur à des conditions d'époxydation en présence du catalyse