Patent ID: 6039902
Filing Date: 2000-03-21
Classification: B01D,B01J,C07C,Y02P

Abstract:
A method of maintaining catalyst in solution after water removal, outside a reaction zone, in a process comprising oxidation of a hydrocarbon by a gaseous oxidant to a respective intermediate oxidation product at an operation temperature in the reaction zone containing a mixture comprising the hydrocarbon, the catalyst, the water, a solvent, and an optional initiator, the method comprising sequential steps of:(a) changing, outside the reaction zone, the operation temperature of the mixture to a second temperature below a precipitation temperature, at which and over which precipitation temperature, the catalyst in the first mixture precipitates, at least partially, if the water level in the first mixture is reduced to or under a precipitation water level, while the catalyst in the first mixture remains in solution if the water level in the first mixture is maintained above the precipitation water level;(b) removing an amount of water from the first mixture, but maintaining the water level in the mixture over the precipitation water level at the second temperature;(c) removing at least part of the intermediate oxidation product; and(d) re-circulating the remaining mixture to the reaction zone.