A METHOD FOR THE ACTIVATION, MAINTENANCE OF ACTIVITY, IMPROVEMENT OF ACTIVITY AND REACTIVATION OF PHOSPHOMOLYBDIC ACID BASED CATALYSTS

摘要

The present invention relates to a method for the activation, maintenance and improvement of activity during reactor shutdown, and reactivation of PMA based catalysts by treating the catalyst precursor with a nitrogen-containing compound such as an oxide of nitrogen gas or a nitrogen acid such as nitric or nitrous at a temperature of from about 10 DEG C to about 400 DEG C. The method can be employed for activation in a reactor by loading the catalyst precursor, adjusting the reactor temperature to one suitable for activation and optionally sweeping the reactor with an inert gas followed by the treating step. The method can also be employed for maintenance of activity of the catalyst in the reactor by terminating the feed of hydrocarbon to the reactor and then flushing the reactor. The method can be employed for catalyst reactivation in the reactor by terminating the feed of reactant to the reactor, adjusting the reactor temperature as may be necessary to one suitable for reactivation and sweeping the reactor with a gas. Alternatively, the catalyst can be removed from the reactor for reactivation.