FIELD: chemistry.
SUBSTANCE: invention relates to a method of producing acrylic acid from ethanol and formaldehyde, which involves following operations: passing through first reaction zone A stream of incoming reaction gas mixture A, containing reagents – ethanol and molecular oxygen, as well as inert diluting gas different from water vapour, and when passing through said reaction zone A ethanol under conditions of heterogeneous catalysis is oxidised to acetic acid and water vapour, so that a gaseous mixture of products A, containing acetic acid, water vapour, molecular oxygen, as well as inert diluting gas different from water vapour is formed, and stream of gaseous mixture of products A leaves reaction zone A, wherein to reaction gas mixture A on its path through reaction zone can be optionally supplied additional molecular oxygen and/or additional inert gas diluent, from a stream of gaseous mixture of products A, leaving reaction zone A, and at least one other stream of substances, which contains at least one source of formaldehyde, receiving stream of incoming reaction gas mixture B containing acetic acid, water vapour, molecular oxygen, inert gas diluent, different from water vapour, and formaldehyde, wherein molar amount of contained acetic acid nNAc is more than contained therein molar amount of formaldehyde nFd, through second reaction zone B, in which is loaded a catalyst for aldol condensation B, passing stream of incoming reaction gas mixture B, and when-passing said reaction zone B formaldehyde contained in incoming reaction gas mixture supplied B, together with acetic acid contained in incoming reaction gas mixture supplied B, in conditions of heterogeneous catalysis is condensed to acrylic acid and water, to form a gaseous mixture of products B containing acrylic acid, acetic acid, water vapour, molecular oxygen, inert gas diluent, different from water vapour, and a stream of gaseous mixture of products B leaves reaction zone B, wherein to reaction gas mixture B on its path through reaction zone B can be optionally supplied additional molecular oxygen and/or additional inert gas diluent, stream of gaseous mixture of products B, leaving reaction zone B is fed into separation zone T, and in said separation zone T is divided at least into three streams substances – X, Y and Z, wherein stream of acrylic acid contained in stream of substance X is larger than flow of acrylic acid contained in streams of substances Y and Z, together taken, stream of acetic acid contained in a stream of substances Y is larger than stream of acetic acid contained in streams of substances X and Z, combined, stream of inert gas diluent, differing from water vapour contained in stream of substance Z, is greater than stream of inert gas diluent, different from water vapour contained in streams of substances X and Y, combined, and a stream of substance Y is fed back into reaction zone B and additionally is used for producing incoming reaction gas mixture B.
EFFECT: method enables to obtain an end product with high selectivity.
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