Process for purification of crude polyether polyols

Patent metadata

Field	Value
Publication number	US-10597490-B2
Application number	US-201615757392-A
Country	US
Kind code	B2
Filing date	Sep 2, 2016
Priority date	Sep 4, 2015
Publication date	Mar 24, 2020
Grant date	Mar 24, 2020

Abstract

A process for the purification of a crude polyether polyol is provided, where the crude polyether polyol is prepared by anionic polymerization of alkylene oxides in the presence of basic catalysts. The process includes neutralizing of the catalysts with mineral acid to form a salt, addition an adsorption agent and/or filter aid and removing the salt and adsorption agent and/or filter aid by filtration to form a filter. In a subsequent step, the filter cake is pressed to recuperate the polyether polyol.

First claim

The invention claimed is:

1. A process for purifying a crude polyether polyol prepared by anionic polymerization of an alkylene oxide in the presence of a basic catalyst, the process comprising
neutralizing the catalyst with a mineral acid to form a salt,
adding an adsorption agent and/or a filter aid,
removing the salt and the adsorption agent and/or the filter aid by filtration to form a filter cake, and
subsequently pressing the filter cake to recuperate the polyether polyol from the filter cake.

2. The process of claim 1 , further comprising:
heating the filter cake prior to pressing the filter cake.

3. The process of claim 2 , wherein a temperature of the filter cake during said pressing ranges from 40° C. to 90° C.

4. The process of claim 1 , wherein the filter cake is pressed using a pressure ranging from 20 to 200 bar.

5. The process of claim 1 , wherein the filter cake is pressed for 1 minute to 10 minutes.

6. The process of claim 1 , wherein a high-pressure chamber press filter is used for pressing the filter cake.

7. The process of claim 1 , wherein the polyether polyol is recuperated from the filter cake by first drying the filter cake by blowing out residual polyether polyol using nitrogen and then subsequently pressing the filter cake.

8. The process of claim 1 , wherein the process is conducted batch-wise, and said pressing is performed at the end of a batch.

9. The process of claim 8 , wherein a cycle time of pressing the filter cake is less than half a cycle time of a batch and one filter press is shared between at least two production lines.

10. The process of claim 1 , further comprising:
blending the recuperated polyether polyol with filtered polyether polyol to obtain a blended polyether polyol such that viscosity and/or residual amounts of the basic catalyst of the blended polyether polyol are within specified ranges.

11. The process of claim 10 , wherein the process is conducted batch-wise, the filter cake is pressed at the end of a batch, and the recuperated polyether polyol is blended with purified polyether polyol of a subsequent batch.

12. The process of claim 11 , wherein the recuperated polyether polyol of the last batch of a production cycle is stored and blended with filtered polyether polyol of the first batch of a subsequent production cycle.

13. The process of claim 1 , wherein a residual amount of polyether polyol in the filter cake after pressing is less than 40% by weight.

14. The process of claim 1 , wherein the basic catalyst is potassium hydroxide.

15. The process of claim 1 , wherein the alkylene oxide is ethylene oxide, propylene oxide, or a mixture of ethylene oxide and propylene oxide.

16. The process of claim 1 , wherein the filter cake after removing the salt and the adsorption agent and/or the filter aid by a filtration is wet filter cake, and the wet filter cake is removed from the filtration and inserted into a press for the subsequent pressing of the wet filter cake.

17. The process of claim 1 , wherein the filtration comprises a plate filter, a candle filter or a chamber filter.

Assignees

• Basf Se

Inventors

• Janssens Vincent Filip
• Akhandaf Yassine

Classifications

• B01D39/00

  Filtering material for liquid or gaseous fluids · CPC title

• B01D29/0093

  Making filtering elements not provided for elsewhere · CPC title

• C08G65/2606

  containing hydroxyl groups · CPC title

• C08G65/2642

  characterised by the catalyst used · CPC title

• C08G65/30 Primary

  Post-polymerisation treatment, e.g. recovery, purification, drying · CPC title