Formaldehyde prepn. by oxidn. of methanol - in a methanol-air mixt. using metal oxide catalysts

摘要

Formaldehyde is prepd. by the oxidn. of MeOH in an MeOH air mixture in the presence of a metal oxide catalyst at 280-420 degrees C, (320-370) degrees C. MeOH or an MeOH-water mixture, in liq. form, is finely divided at 20-150 degrees C/3-20 bars press. into droplets 1-1000, (1-200) mu m in dia. The droplets are then (partially) vaporised in air at 140-350 degrees C/1.2-2 bars pressure and the resulting mixt. of air and MeOH or air, MeOH and water reacted as above. HCHO is obtd. in improved yields, vol-time yields and purity. Only small amts. of impurities, e.g. HCOOH, or unreacted MeOH are obtained. The catalyst exhibits longer life, esp. at high throughputs.