Maintaining activity of cuprous oxide catalyst in oxidation of olefins

Claim 1

IN A PROCESS FOR THE OXIDATION OF AN OLEFIN CONTAINING AT LEAST THREE CARBON ATOMS TO A PRODUCT OF PARTIAL OXIDATION BY REACTION WITH MOLECULAR OXYGEN IN THE PRESENCE OF A MOBILE BED OF A SOLID CATALYST ESSENTIALLY COMPRISING CUPROUS OXIDE, WHEREIN A GASEOUS MIXTURE COMPRISING SAID OLEFIN AND MOLECULAR OXYGEN IS PASSED INTO CONTACT WITH THE CATALYST IN A FIRST REACTION ZONE MAINTAINED UNDER CONDITIONS OF OPERATION CONDUCIVE TO GRADUAL DEACTIVATION OF THE CATALYST, THE METHOD OF MAINTAINING, OR RESTORING HIGH ACTIVITY OF THE CATALYST WHICH COMPRISES TRANSFERRING PARTIALLY DEACTIVATED CATALYST WHICH IS FREE OF MATERIAL DEPOSITS OF CARBONACEOUS, TARRY AND LIKE MATERIAL FROM SAID REACTION ZONE TO A SECOND REACTION ZONE, THEREIN PASSING A GASEOUS MIXTURE COMPRISING SAID OLEFIN AND OXYGEN INTO CONTACT WITH THE CATALYST AT CONDITIONS OF AT LEAST ONE OF: TEMPERATURE AND PRESSURE, DIFFERING FROM THOSE IN THE FIRST REACTION ZONE BY AN AMOUNT REPRESENTED BY A VALUE OF 1.1 TO 4.0 FOR THE RATIO