A process for the regeneration of a catalyst comprising a titanium containing zeolite of MWW framework structure as catalytically active material, comprising (i) a stage comprising (a) continuously preparing propylene oxide comprising introducing a feed stream comprising propene, hydrogen peroxide or a hydrogen peroxide source, and an organic solvent into a reactor containing a catalyst comprising the titanium containing zeolite of MWW framework structure as catalytically active material; subjecting the feed stream according to in the reactor to epoxidation conditions in the presence of the catalyst, obtaining a reaction mixture comprising the propylene oxide and the organic solvent; removing a product stream comprising the propylene oxide and the organic solvent from the reactor; (b) stopping introducing the feed stream into the reactor; (c) washing the catalyst in the reactor containing the catalyst with a liquid aqueous system containing at least 95 weight-% water, based on the total weight of the liquid aqueous system, wherein the washing is performed for 2 to 12 hours; stage (i) further comprising repeating the sequence of steps (a) to (c) n times with n being an integer in the range of from 1 to 10; the process for the regeneration further comprising (ii) a stage comprising calcining the catalyst obtained from (c) after having repeated the sequence of steps (a) to (c) n times, wherein the calcining is performed at a temperature of the catalyst in the range of from 300 to 600 °C using a gas stream comprising oxygen in the reactor containing the catalyst; wherein the sequence of stages (i) to (ii) is optionally repeated m times with m being an integer and being at least 1, wherein in each repetition of the sequence of stages (i) to (ii), n is the same or different. (i) a stage comprising (a) continuously preparing propylene oxide comprising introducing a feed stream comprising propene, hydrogen peroxide or a hydrogen peroxide source, and an organic solvent into a reactor containing a catalyst comprising the titanium containing zeolite of MWW framework structure as catalytically active material; subjecting the feed stream according to in the reactor to epoxidation conditions in the presence of the catalyst, obtaining a reaction mixture comprising the propylene oxide and the organic solvent; removing a product stream comprising the propylene oxide and the organic solvent from the reactor; (b) stopping introducing the feed stream into the reactor; (c) washing the catalyst in the reactor containing the catalyst with a liquid aqueous system containing at least 95 weight-% water, based on the total weight of the liquid aqueous system, wherein the washing is performed for 2 to 12 hours; stage (i) further comprising repeating the sequence of steps (a) to (c) n times with n being an integer in the range of from 1 to 10; the process for the regeneration further comprising (a) continuously preparing propylene oxide comprising introducing a feed stream comprising propene, hydrogen peroxide or a hydrogen peroxide source, and an organic solvent into a reactor containing a catalyst comprising the titanium containing zeolite of MWW framework structure as catalytically active material; subjecting the feed stream according to in the reactor to epoxidation conditions in the presence of the catalyst, obtaining a reaction mixture comprising the propylene oxide and the organic solvent; removing a product stream comprising the propylene oxide and the organic solvent from the reactor; introducing a feed stream comprising propene, hydrogen peroxide or a hydrogen peroxide source, and an organic solvent into a reactor containing a catalyst comprising the titanium containing zeolite of MWW framework structure as catalytically active material; subjecting the feed stream according to in the reactor to epoxidation conditions in the presence of the catalyst, obtaining a reaction mixture comprising the propylene oxide and the organic solvent; removing a product stream comprising the propylene oxide and the organic solvent from the reactor; (b) stopping introducing the feed stream into the reactor; (c) washing the catalyst in the reactor containing the catalyst with a liquid aqueous system containing at least 95 weight-% water, based on the total weight of the liquid aqueous system, wherein the washing is performed for 2 to 12 hours; (ii) a stage comprising calcining the catalyst obtained from (c) after having repeated the sequence of steps (a) to (c) n times, wherein the calcining is performed at a temperature of the catalyst in the range of from 300 to 600 °C using a gas stream comprising oxygen in the reactor containing the catalyst;