| abstract |
The invention relates to a method of producing an ethylenically unsaturated carboxylic acid or ester, preferably an α, β ethylenically unsaturated carboxylic acid or ester. The method includes contacting formaldehyde or a suitable source thereof with a carboxylic acid or ester in the presence of a catalyst and optionally in the presence of an alcohol. The catalyst comprises a nitrided metal oxide having at least two types of metal cations, M |