Abstract: A process for continuously preparing a butyl acrylate H2C?CH—C(?O)OR, with R=n-butyl or isobutyl, wherein aqueous 3-hydroxypropionic acid is converted under dehydrating and esterifying conditions in the presence of the corresponding butanol R—OH in a reactor with a rectification column and butyl acrylate formed, unconverted butanol and water used and formed are distilled off overhead as a ternary azeotrope, after separation into a liquid aqueous phase and liquid organic phase each of the aqueous and organic phases is at least partly discharged, and the organic phase comprising the butyl acrylate and the butanol is subjected to distillative separation.

Abstract: A process for continuously preparing a butyl acrylate H2C?CH—C(?O)OR, with R=n-butyl or isobutyl, wherein aqueous 3-hydroxypropionic acid is converted under dehydrating and esterifying conditions in the presence of the corresponding butanol R—OH in a reactor with a rectification column and butyl acrylate formed, unconverted butanol and water used and formed are distilled off overhead as a ternary azeotrope, after separation into a liquid aqueous phase and liquid organic phase each of the aqueous and organic phases is at least partly discharged, and the organic phase comprising the butyl acrylate and the butanol is subjected to distillative separation.

Abstract: The invention relates to a process for dehydrating aqueous 3-hydroxypropionic acid to acrylic acid in the liquid phase, wherein aqueous acrylic acid is removed continuously from the liquid phase and the aqueous 3-hydroxypropionic acid and/or the liquid phase have a high content of oligomeric 3-hydroxypropionic acid.

Abstract: The invention relates to a crossflow tray for a mass transfer column (27) in which a gas is conducted in countercurrent to a liquid, the crossflow tray (1) having passage orifices (3) for the gas and at least two downcomers (5), the downcomers (5) projecting beyond the top surface of the crossflow tray (1) and a collecting cup (13) being disposed beneath each downcomer (5). The downcomer (5) projects into the collecting cup (13), the minimum horizontal cross-sectional area of the collecting cup (13) is 1.2 to 4 times greater than the horizontal cross-sectional area of the downcomer (5) at the outlet, and the collecting cup (13) has a circumferential wall (15) having an overflow (19). The invention further relates to a mass transfer column comprising the crossflow trays and to a use of the mass transfer column.

Abstract: The invention relates to a process for dehydrating aqueous 3-hydroxypropionic acid to acrylic acid, wherein an aqueous mixture of 3-hydroxypropionic acid and oligomeric 3-hydroxypropionic acid is converted to acrylic acid in the liquid phase in a first step and aqueous acrylic acid is distilled out of the liquid phase, and the aqueous acrylic acid is separated by distillation into an acrylic acid-rich phase and a water-rich phase in a second step.

Abstract: The invention relates to a process for dehydrating aqueous 3-hydroxypropionic acid to acrylic acid in the liquid phase, wherein aqueous acrylic acid is removed continuously from the liquid phase and the liquid phase comprises an inert organic solvent 1.

Abstract: The invention relates to a process for dehydrating aqueous 3-hydroxypropionic acid to acrylic acid, wherein an aqueous mixture of 3-hydroxypropionic acid and oligomeric 3-hydroxypropionic acid is converted to acrylic acid in the liquid phase in a first step and aqueous acrylic acid is distilled out of the liquid phase, and the aqueous acrylic acid is separated by distillation into an acrylic acid-rich phase and a water-rich phase in a second step.

Abstract: A process for preparing acrylic acid from methanol and acetic acid, comprising (i) contacting a gaseous stream S0 comprising methanol, oxygen and inert gas with an oxidation catalyst to obtain a gaseous stream S1 comprising formaldehyde and inert gas; (ii) removing at least a portion of the inert gas present in S1 from at least a portion of the formaldehyde present in S1 by absorbing this formaldehyde in an absorbent to obtain a gaseous stream S2 comprising the portion of the inert gas removed, and to obtain a stream S3 comprising absorbent and absorbate comprising formaldehyde; (iii) optionally removing a portion or the entirety of the absorbent present in stream S3, such that a stream S3a remains from stream S3, and producing a stream S4 from at least stream S3 or stream S3a and a stream S5 comprising acetic acid; and (iv) contacting stream S4 in gaseous form with an aldol condensation catalyst to obtain a gaseous stream S6 comprising acrylic acid.

Abstract: A process for obtaining acrylic acid, comprising (a) providing a liquid stream S7 comprising acetic acid and acrylic acid, where the molar ratio of acetic acid to acrylic acid in stream S7 is greater than 1:1, (b-1) crystallizing a portion of the acetic acid present in stream S7 to obtain solid crystallized acetic acid in its mother liquor, (b-2) separating the mother liquor from the acetic acid crystallized in (b-1) to obtain the solid crystallized acetic acid and a liquid stream S8 comprising acrylic acid and acetic acid, (c) separating stream S8 into at least one stream S10 depleted of acrylic acid compared to S8 and a stream S11 enriched in acrylic acid compared to S8.

Abstract: The invention relates to a crossflow tray for a mass transfer column (27) in which a gas is conducted in countercurrent to a liquid, the crossflow tray (1) having passage orifices (3) for the gas and at least two downcomers (5), the downcomers (5) projecting beyond the top surface of the crossflow tray (1) and a collecting cup (13) being disposed beneath each downcomer (5). The downcomer (5) projects into the collecting cup (13), the minimum horizontal cross-sectional area of the collecting cup (13) is 1.2 to 4 times greater than the horizontal cross-sectional area of the downcomer (5) at the outlet, and the collecting cup (13) has a circumferential wall (15) having an overflow (19). The invention further relates to a mass transfer column comprising the crossflow trays and to a use of the mass transfer column.

Abstract: The invention relates to a process for dehydrating aqueous 3-hydroxypropionic acid to acrylic acid in the liquid phase, wherein aqueous acrylic acid is removed continuously from the liquid phase and the liquid phase comprises an inert organic solvent 1.

Abstract: The invention relates to a process for dehydrating aqueous 3-hydroxypropionic acid to acrylic acid in the liquid phase, wherein aqueous acrylic acid is removed continuously from the liquid phase and the aqueous 3-hydroxypropionic acid and/or the liquid phase have a high content of oligomeric 3-hydroxypropionic acid.

Abstract: A process for obtaining acrylic acid, comprising (a) providing a liquid stream S7 comprising acetic acid and acrylic acid, where the molar ratio of acetic acid to acrylic acid in stream S7 is greater than 1:1, (b-1) crystallizing a portion of the acetic acid present in stream S7 to obtain solid crystallized acetic acid in its mother liquor, (b-2) separating the mother liquor from the acetic acid crystallized in (b-1) to obtain the solid crystallized acetic acid and a liquid stream S8 comprising acrylic acid and acetic acid, (c) separating stream S8 into at least one stream S10 depleted of acrylic acid compared to S8 and a stream S11 enriched in acrylic acid compared to S8.

Abstract: A process for preparing acrylic acid from methanol and acetic acid, comprising (i) contacting a gaseous stream S0 comprising methanol, oxygen and inert gas with an oxidation catalyst to obtain a gaseous stream S1 comprising formaldehyde and inert gas; (ii) removing at least a portion of the inert gas present in S1 from at least a portion of the formaldehyde present in S1 by absorbing this formaldehyde in an absorbent to obtain a gaseous stream S2 comprising the portion of the inert gas removed, and to obtain a stream S3 comprising absorbent and absorbate comprising formaldehyde; (iii) optionally removing a portion or the entirety of the absorbent present in stream S3, such that a stream S3a remains from stream S3, and producing a stream S4 from at least stream S3 or stream S3a and a stream S5 comprising acetic acid; and (iv) contacting stream S4 in gaseous form with an aldol condensation catalyst to obtain a gaseous stream S6 comprising acrylic acid.

Abstract: In a process for preparing acrylic acid, a reaction gas which comprises a gaseous formaldehyde source and gaseous acetic acid and in which the partial pressure of the formaldehyde source, calculated as formaldehyde equivalents, is at least 85 mbar and in which the molar ratio of the acetic acid to the formaldehyde source, calculated as formaldehyde equivalents, is at least 1 is contacted with a solid condensation catalyst. The space-time yield can be enhanced significantly by increasing the partial pressure of the reactants. The space-time yield remains high even after prolonged process duration.