| abstract |
FIELD: chemistry. n SUBSTANCE: invention relates to method of producing α, β ethylenically unsaturated carboxylic acid or its ester, such as methacrylic acid or its alkyl ethers, for example, methyl methacrylate. Method involves stages of interaction of formaldehyde or suitable source thereof with carboxylic acid or its ester, for example, propionic acid or its alkyl ethers, in presence of catalyst and optionally in presence of alcohol, selected from C 1 -C 30 alkanol, including aryl-alcohols. Catalyst contains group II metal phosphate crystals, having rod- or needle-like morphology. Phosphate can be hydroxyapatite, pyrophosphate, hydroxyphosphate, PO 4 2- phosphate or their mixture. Metal of group II can be selected from Ca, Sr, Ba or mixtures thereof, for example hydroxyapatite strontium and calcium hydroxyapatite. Invention also relates to catalyst system containing crystalline metal phosphate catalyst and catalyst carrier. Metal phosphate has rod- or needle-like morphology. n EFFECT: technical result is high selectivity of product. n 19 cl, 10 tbl, 24 ex |