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:
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 preparing acrylic acid from ethylene oxide and carbon monoxide, in which ethylene oxide is carbonylated in an aprotic solvent with carbon monoxide in the presence of a cobalt catalyst system to give poly-3-hydroxypropionate, the cobalt content in the poly-3-hydroxypropionate formed is reduced with the aid of water and/or an aqueous solution as a precipitation and/or wash liquid, and the poly-3-hydroxypropionate is subsequently split by thermolysis to give acrylic acid.
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 preparing acrylic acid from ethylene oxide and carbon monoxide, in which ethylene oxide is carbonylated in an aprotic solvent with carbon monoxide in the presence of a cobalt catalyst system to give poly-3-hydroxypropionate, the cobalt content in the poly-3-hydroxypropionate formed is reduced with the aid of water and/or an aqueous solution as a precipitation and/or wash liquid, and the poly-3-hydroxypropionate is subsequently split by thermolysis to give 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.
Abstract:
A process for preparing acrylic acid by thermolysis of poly-3-hydroxypropionate in the presence of one or more specific tertiary amines as a catalyst.