Process and plant for the purification of acrylic acid

Patent metadata

Field	Value
Publication number	US-10029976-B2
Application number	US-201515317755-A
Country	US
Kind code	B2
Filing date	Jun 16, 2015
Priority date	Jun 26, 2014
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

Furthermore, the invention may include a plant for carrying out this process.

First claim

The invention claimed is:

1. A process for the purification of acrylic acid from a mixture containing acrylic acid and acetic acid, comprising the following steps:
i) extracting the mixture containing acrylic acid and acetic acid with an extractant stream, whereby a raffinate stream and an extract stream are obtained; and
ii) distilling the extract stream, whereby an acrylic acid stream and a return stream are obtained,
wherein the return stream contains acetic acid and is recirculated into the extraction,
wherein for the extraction a mixture of isopropyl acetate and cyclohexane is used as extracting agent,
wherein before the distillation of the extract stream cyclohexane is separated from the extract stream.

2. The process as claimed in claim 1 , wherein an absolute amount of acetic acid in the raffinate stream is greater than an absolute amount of acetic acid in the return stream.

3. The process as claimed in claim 1 , wherein the return stream contains at least 90 wt-% of the acetic acid contained in the extract stream.

4. The process as claimed in claim 1 , wherein before the extraction the mixture containing acrylic acid and acetic acid is mixed with a liquid.

5. The process as claimed in claim 1 , wherein the raffinate stream is separated into a stripping agent stream and a residual stream by means of stripping, wherein the acetic acid contained in the raffinate stream remains in the stripping agent stream.

6. The process as claimed in claim 5 , wherein the residual stream is supplied to the extractant stream.

7. The process as claimed in claim 6 , wherein the residual stream is separated into a less dense and into a denser phase, wherein the less dense phase is supplied to the extractant stream and the denser phase is supplied to the raffinate stream.

8. The process as claimed in claim 1 , wherein that the distillation of the extract stream is carried out in two stages, wherein in a first distillation stage the acrylic acid stream is at least partly discharged and a remaining stream of a second distillation stage is separated into a return stream and a recirculation stream, wherein the recirculation stream is completely recirculated into the first stage of the distillation.

Assignees

• Air Liquide
• Air Liquide

Inventors

• Gutermuth Thomas
• Kreich Markus
• Castillo-Welter Frank

Classifications

• C07C51/44 Primary

  by distillation · CPC title

• C07C51/48 Primary

  by liquid-liquid treatment · CPC title

• B01D3/143

  by two or more of a fractionation, separation or rectification step · CPC title

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title

• B01D11/0492

  Applications, solvents used · CPC title