BigPatents India

The invention relates to a method for producing a cycloolefin by partially hydrogenating a single-ring aromatic hydrocarbon in the presence of a ruthenium catalyst, which comprises the steps of · Bringing the ruthenium catalyst, whose activity has decreased in the hydrogenation, into contact with oxygen in a liquid phase; · Maintaining the catalyst at a hydrogen partial pressure lower than that at the hydrogenation and at a temperature not lower than a temperature lower than 500C than the hydrogenation temperature to obtain a ruthenium catalyst restored in activity; and · Partially hydrogenating the single-ring aromatic hydrocarbon in the presence of the ruthenium catalyst restored in activity. (FIG : Nil.)