| abstract |
FIELD: chemistry. n SUBSTANCE: invention relates to a process of preparing α ethylenically unsaturated β carboxylic acid or an ester thereof, comprising the steps of driving the formaldehyde contact or a usable source with a carboxylic acid or its ester in the presence of a catalyst and optionally in the presence of an alcohol, wherein the catalyst contains crystals of barium phosphate shaped leaf plates or similar sheets or plates, or a suitable source for use is capable of forming crystals in situ under the reaction conditions. The invention also relates to a catalyst system of the reaction of formaldehyde, or a suitable source for use with a carboxylic acid or an ester thereof to obtain α,β-ethylene-unsaturated carboxylic acid or an ester thereof containing a catalyst based on crystalline barium phosphate and, optionally, a catalyst carrier, wherein the barium phosphate is in the form of crystals having the form of leaves or plates similar to plates or leaves, or suitable for use source capable of forming crystals in situ under the reaction conditions. n EFFECT: high level of selectivity of the above reactions. n 61 cl, 9 dwg, 1 tbl, 8 ex |