use of a melt of vanadium pentoxide and potassium sulphate as a catalyst for the catalytic oxidation of naphthalene to phthalsaeureanhydrid

摘要

In a process for the production of glass, vanadium pentoxide is dissolved in molten potassium pyrosulphate in a molecular ratio of K2O:V2O5 bewteen 1:1 and 6:1 and the solution is allowed to cool and solidity. The potassium pyrosulphate may be formed by heating together potassium sulphate and sulphuric acid and adding vanadium pentoxide thereto so as to provide a K2O : V2O5 ratio within the above range, heating the resulting solution between 350 DEG and 400 DEG C. to drive off any surplus sulphur trioxide and allowing the whole to cool to a solid glass, the latter being subsequently crushed to form catalyst particles. The catalyst particles may be used in the oxidation of polynuclear aromatic compounds and especially the oxidation of napththalene to phthalic anhydride. An example is given.