The production of furan by the vapor-phase oxidation of butadiene using heteropoly compounds as catalysts

Abstract

Supported heteropoly compounds, such as salts of 12-molybdophosphoric acid (H 3PMo 12O 40), were found to be effective as catalysts for the synthesis of furan in the vapor-phase oxidation of 1,3-butadiene. The rate of the reaction increases with the contents of oxygen and steam in the feed gas, whereas it decreases with the butadiene content. The yield of furan attains a maximum at a conversion of about 70%, regardless of the reaction conditions and the catalysts. From tests on 18 salts of 12-molybdophosphoric acid with an M n+ Mo atomic ratio of 1 12n ( M 1 n H 2PMo 12O 40 ) as catalysts, it was found that the best results for furan formation are obtained with the cesium, sodium, and ammonium salts. The effect of cesium content was also studied. The best results for both the yield of furan and the oxidation activity are obtained at a Cs Mo atomic ratio of from 1 12 to 1.5 12 . The results were discussed in the light of the acid-base properties of the cataysts.