| 摘要 |
The present invention relates to a method for maintaining the activity of PMA based catalysts during reactor shutdown by flushing the reactor with an oxide of nitrogen gas at a temperature of from about 150 DEG C. to about 370 DEG C. The method can be employed in the reactor by terminating the feed of hydrocarbon to the reactor and then flushing the reactor. The method can be employed to treat PMA based catalysts having the general formula MoxPyAaBbCcDdEeOz wherein A is selected from the group consisting of ammonium, cesium, potassium, rubidium and thallium; B is selected from the group consisting of copper and vanadium; C is selected from the group consisting of antimony, arsenic, bismuth and tellurium; D is palladium; E is aluminum, barium, calcium, cerium, chromium, cobalt, iron, magnesium, manganese, nickel tantalum, titanium, tungsten, zinc, zirconium, chlorine and/or bromine; x can be 3 to 15, y can be 1 to 1.5; a can be 0.1 to 3; b can be 0.1 to 3; c can be 0 to 2; d can be 0 to 2; e can be 0 to 4 and z is a number necessary to satisfy the valence of all the other elements.
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