PRODUCTION OF FURAN BY VAPOR-PHASE OXIDATION OF CROTONALDEHYDE USING HETEROPOLY COMPOUNDS AS CATALYSTS

The synthesis of furan by direct vapor-phase oxidation of crotonaldehyde was studied. It is found that heteropoly compounds such as 12-molybdophosphoric acid are more effective than the mixed oxide (MoO//3-P//2O//5, P/Mo equals 1/12) as catalyst for furan formation, and that the cesium salt of 12-molybdophosphoric acid with a Cs/Mo atomic ratio of 1/12 is more effective than the 12-molybdophosphoric acid catalyst. The rate of furan formation increases with increase in steam concentration in the feed, but is nearly independent of oxygen and crotonaldehyde concentrations. The yield of furan increases by decreasing the crotonaldehyde concentration, attaining 60 mol% at a concentration of 0. 17 vol% in the feed. The conversion of crotonaldehyde at maximum yield is 90-95%.