Process of oxidizing monoketones

Claim 1

IN A CONTINUOUS PROCESS FOR OXIDIZING METHYL ETHYL KETONE BY DIRECT REACTION WITH MOLECULAR OXYGEN IN THE PRESENCE OF A CATALYST ESSENTIALLY COMPRISING CUPROUS OXIDE TO FROM DIACETYL, WHICH PROCESS COMPRISING PASSING A GASEUOS MIXTURE COMPRISING METHYL ETHYL KETONE AND MOLECULAR OXYGEN IN A MOLAR RATIO OF AT LEAST 2 TO 1 INTO CONTACT WITH SAID CATALYST AT A TEMPERATURE FROM ABOUT 150* C. TO ABOUT 450* C., WHEREBY THERE IS FORMED A GASEOUS PRODUCT CONTAINING DIACETYL, SEPARATING SAID PRODUCT FROM THE CATALYST, THE IMPROVEMENT WHEREBY A HIGH LEVEL OF CATALYST ACTIVITY IS MAINTAINED, SAID IMPROVEMENT CONSISTING OF AT INTERVALS OF TIME DECREASING FOR A BRIEF PERIOD OF TIME THE FLOW OF MOLECULAR OXYGEN TOTHE CATALYST WHILE MAINTAINING THE CONDITIONS OTHERWISE SUBSTANTIALLY UNCHANGED, AND AFTER EACH PERIOD OF DECREASED FLOW OF OXYGEN TO THE CATALYST RESTORING THE FLOW OF OXYGEN TO THE CATALYST.