Basf Se Corporation

Till Christian Brueggemann

Nicolai Tonio Woerz

Yong Liang Liu

Marco Hartmann

Michael Ludwik Lejkowski

Lukas Schulz

Johannes Lieberknecht

Wolfgang Siegel

Stephan Freyer

Gabriele Iffland

Jens Wittenberg

Suman Thotla

Stefanie Demming

Yvonne Hoelzl

Astrid Ruppel

The invention relates to a process for continuously preparing di-C-alkyl succinates by reacting succinic acid with an C-alkanol in the presence of a fixed-bed heterogeneous acidic esterification catalyst in a tubular reactor at a temperature in the range of from 60 to 100&#xb0; C., wherein a mixture, comprising succinic acid, C-alkanol, mono-C-alkyl succinate, di-C-alkyl succinate and water, is formed in a mixing stage and fed to the entrance of the tubular reactor, and wherein 5 to 75% of the outlet flow rate of the tubular reactor are recycled directly to the mixing stage as a recycle stream, and the molar ratio of C-alkanol to succinic acid added to the mixing zone, and not including the C-alkanol and succinic acid at the recycle stream, being in the range of from 2.0 to 9.5. The invention furthermore relates to a process for separating the reactor effluent of an esterification of succinic acid with an C-alkanol to give di-C1-3-alkyl succinates by distillation, wherein the separation is performed in a divided wall column in which C-alkanol and water are removed in a top draw of the column, di-C-alkyl succinate is removed in a side draw of the column, and wherein mono-C-alkyl succinate and succinic acid are removed in a bottom draw of the column.

[object Object]

The invention relates to a process for preparing acrylic acid from formaldehyde and acetic acid, comprising

Process for preparing acrylic acid from formaldehyde and acetic acid

A process for preparing acrylic acid from formaldehyde and acetic acid, is performed by (i) providing a gaseous stream S1 comprising formaldehyde, acetic acid, oxygen and water, where the formaldehyde content of stream S1 is in the range from 8% to 18% by volume, based on the total volume of stream S1, the ratio of the volumes of acetic acid to formaldehyde is in the range from 0.6:1 to 1.1:1, and the molar ratio of oxygen to the total amount of organic carbon is in the range from 0.02:1 to 0.15:1; and (ii) contacting stream S1 with an aldol condensation catalyst in a reaction zone to obtain a gaseous stream S2 containing acrylic acid.

Process for preparing acrylic acid

The present invention relates to a process for preparing acrylic acid from formaldehyde and acetic acid, comprising reacting formaldehyde and acetic acid via an aldol condensation in a reaction unit comprising n reaction zones arranged in series, each comprising an aldol condensation catalyst, where n is at least 2, and wherein at least one stream leaving a reaction zone, before being fed into the reaction zone immediately downstream, is mixed with a stream comprising formaldehyde and optionally comprising acetic acid. The present invention further relates to an apparatus for preparing acrylic acid from formaldehyde and acetic acid and to the use of this apparatus.

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Ludwigshafen, Germany

Till Christian Brueggemann