Process for preparing vinylidenecarboxylic acid (ester)s by reaction of formaldehyde with alkylcarboxylic acid (ester)s

摘要

Process for preparing a vinylidenecarboxylic acid or ester thereof, wherein a reaction gas comprising gaseous formaldehyde, molecular oxygen and an alkycarboxylic acid or ester thereof is brought into contact with a solid catalyst whose active composition comprises a vanadium-phosphorus oxide having an average oxidation state of vanadium of from +4.40 to +5.0 to give a product gas comprising the vinylidenecarboxylic acid or ester thereof.

主权项

1. A process for preparing a compound of formula (I), where R1 and R2 are each, independently of one another, H or (C1-C4)-alkyl, the process comprising contacting (i) a reaction gas comprising gaseous formaldehyde, molecular oxygen and a gaseous compound of formula (II) with (ii) a solid catalyst whose active composition comprises a vanadium-phosphorus oxide having an average oxidation state of vanadium of from greater than +4.65 to +5.0, to obtain a product gas comprising the compound of the formula (I).