1-Butanol dehydration and oxidation over vanadium phosphate catalysts

The transformation of 1-butanol into either butenes or maleic anhydride was carried out both with and without oxygen, using V/P/O catalysts. With vanadyl pyrophosphate prepared by coprecipitation, at temperature lower than 240 °C and without oxygen, selectivity to butenes was higher than 90%, but a slow deactivation took place. At temperature higher than 300 °C and in the presence of air, maleic and phthalic anhydrides were the prevailing products, with selectivity of 60% and 14%, respectively. Catalytic performance was affected by crystallinity and acidity. αI-VOPO4 showed a poor performance in the absence of air, with a quick deactivation due to coke accumulation; but it displayed an excellent selectivity to butenes (close to 98%) at temperatures lower than 320 °C in the presence of air, with stable performance. At temperature higher than 360 °C, α I-VOPO4 was reduced to vanadyl pyrophosphate and catalyzed the direct oxidation of 1-butanol into maleic anhydride, but with 35% selectivity. [Display omitted] •(VO)2P2O7 catalyses 1-butanol oxidation to maleic anhydride with 60% yield.•The maximum yield to maleic anhydride decreases on increasing 1-butanol inlet concentration.•Both (VO)2P2O7 and αI-VOPO4 catalyse 1-butanol dehydration to butenes but deactivate.•In the presence of O2, αI-VOPO4 catalyses 1-butanol dehydration with 98% yield to butenes.•The catalytic performance of αI-VOPO4 in the presence of O2 is also very stable, with no deactivation.