FIELD: chemical or physical processes.
SUBSTANCE: invention relates to a multimodal silica catalyst and a method of producing ethylenically unsaturated carboxylic acids or esters. Described is a catalyst for producing α,β-unsaturated carboxylic acids or esters, containing a silica support, a modifier metal and a catalytic alkali metal, where the silica support has a multimodal pore size distribution, comprising: a) a mesoporous pore size distribution having an average pore size in range of 2 to 50 nm and a volume of said mesopores in range of 0.2 to 3 cm3/g; and b) a macroporous pore size distribution having an average pore size in range of 50 to 1,000 nm and a volume of said macropores in range of 0.1 to 3 cm3/g, where the level of the catalytic alkali metal on the silica support ranges from 2 to 10 mol.%, and where the modifier metal is selected from Mg, B, Al, Ti, Zr and Hf. Method of producing said catalyst comprises steps of: (a) preparing an oxide for a silica support which is modified with a modifier metal selected from Mg, B, Al, Ti, Zr and Hf; (b) treating the modified silicon oxide with a catalytic alkali metal to obtain a catalyst; (c) macropores are added to the silica support before step (a), before step (b) or after step (b). Also described is a method of producing an ethylenically unsaturated carboxylic acid or ester, comprising steps of, on which formaldehyde or a suitable source thereof is reacted with a carboxylic acid or an ester in the presence of the above catalyst. Disclosed is a method of producing ethylenically unsaturated carboxylic acid or ester, in which alkanoic acid or ester of formula R1-CH2-COOR3 is reacted with formaldehyde or a suitable source of formaldehyde with formula (I), where R5 denotes methyl, and R6 denotes H; X denotes O; m is equal to 1; and n is integer from 1 to 20, or any mixture thereof; in the presence of the above catalyst; where R1 is hydrogen or an alkyl group with 1–12 carbon atoms, and R3 independently represents hydrogen or an alkyl group with 1–12 carbon atoms.
EFFECT: high selectivity of the reaction and/or reduced formation of heavy products.
32 cl, 4 dwg, 2 tbl, 32 ex
