high productivity process to produce n-butane maleic anhydride.

摘要

A process for the preparation of oxidation catalysts containing vanadium-phosphorus mixed oxides, consisting of:a) contacting a phosphorus compound with a vanadium compound in an organic solvent under conditions allowing the preparation, recovery, drying of said precursor,b) submitting the precursor, prior to calcination, to a treatment by contacting with a stream of dry inert gas containing vapors of an aliphatic anhydride, having from 4 to 8 carbon atoms, preferably acetic anhydride, at a temperature not exceeding 200° C.,c) calcinating the precursor under an atmosphere containing air, steam, or inert gas or a mixture of them at a temperature between 350° C. and 550° C. at controlled rate of temperature increase during the time necessary to obtain active catalysts,d) using of said catalysts for the production of maleic anhydride by oxidation of aliphatic hydrocarbons.The catalysts prepared according the procedures of this invention are particularly suited for use for the production of maleic anhydride, preferably by partial or total gas recycle process.