Patent ID: 6156938
Filing Date: 2000-12-05
Classification: C07C,Y02P

Abstract:
A process for hydroxylating an aromatic compound, comprising:contacting an aromatic compound with a catalyst having an average concentration of .alpha.-sites of at least about 1.multidot.10.sup.16 per gram of catalyst, the catalyst having .alpha.-oxygen loaded thereon, whereby an hydroxylated derivative of the aromatic compound is produced;reloading the catalyst with .alpha.-oxygen by contacting the catalyst with a free oxidant activator; anddetermining the progress of the reloading by:passing an input gas stream over the catalyst, the input gas stream comprising an inert gas;collecting an output gas stream that has passed over the catalyst;introducing a plurality of nitrous oxide impulses into the input gas stream, each impulse being separated by a period in which the input gas stream contains no nitrous oxide;measuring the concentrations of nitrous oxide and nitrogen gas in the output gas stream after an impulse of nitrous oxide is introduced; andcomparing the concentrations of nitrogen gas and nitrous oxide in the output gas stream.