Processes for purifying polyether polyols using ion exchange resins

Patent metadata

Field	Value
Publication number	US-12515212-B2
Application number	US-202318371808-A
Country	US
Kind code	B2
Filing date	Sep 22, 2023
Priority date	Oct 12, 2022
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

Processes for purifying polyether polyols via treatment with ion exchange resins. A mixture that includes the polyether polyol and alkali metal ions is passed through a first bed that includes a cation exchange resin comprising carboxylic acid and/or phosphonic acid groups to remove alkali metal ions from the mixture. Thereafter, the product is passed through a second bed comprising an anion exchange resin comprising quaternary ammonium groups and a cation exchange resin comprising carboxylic acid and/or phosphonic acid groups to thereby produce a purified polyether polyol.

First claim

What is claimed is:

1 . A process for removing alkali metal ions from a polyether polyol, comprising: (a) passing a mixture comprising the polyether polyol and the alkali metal ions through a first bed comprising a cation exchange resin comprising carboxylic acid and/or phosphonic acid groups to remove alkali metal ions from the mixture; and (b) passing the product of step (a) through a second bed comprising an anion exchange resin comprising quaternary ammonium groups and a cation exchange resin comprising carboxylic acid and/or phosphonic acid groups to thereby produce a purified polyether polyol, wherein the first bed and the second bed are each free of a cation exchange resin that comprises sulfonic acid groups.

2 . The process of claim 1 , wherein the polyether polyol has a hydroxyl number of no more than 56 mg KOH/gram, measured according to ASTM D4274-16.

3 . The process of claim 2 , wherein the polyether polyol has a hydroxyl number of 25 to 35 mg KOH/gram, measured according to ASTM D4274-16.

4 . The process of claim 1 , wherein the mixture comprising the polyether polyol and the alkali metal ions is combined with a mixture comprising water and a polar organic solvent prior to passing the mixture comprising the polyether polyol and the alkali metal ions through the first bed, wherein a relative weight ratio of polar organic solvent and water in the mixture comprising water and polar organic solvent is within a range of 1:1 to 10:1.

5 . The process of claim 4 , wherein the mixture comprising water and polar organic solvent is present in an amount of 10 to 40% by weight, based on the total combined weight of (i) the mixture comprising water and polar organic solvent and (ii) the mixture comprising the polyether polyol and the alkali metal ions.

6 . The process of claim 1 , wherein at least one of a container that includes the first bed and a container that includes the second bed is operated liquid-full throughout the process.

7 . The process of claim 6 , wherein the liquid level in the container operated liquid-full throughout the process is maintained at a level that is at least 95% of the total container height throughout the process.

8 . The process of claim 1 , wherein cation exchange resin that comprises sulfonic acid groups is present in an amount of no more than 1% by weight, based on the total weight of ion exchange resin used in each bed.

9 . The process of claim 1 , further comprising removing organic solvent and water from the purified polyether polyol.

10 . The process of claim 9 , wherein the removing organic solvent and water from the purified polyether polyol comprises at least atmospheric distillation and vacuum distillation.

11 . The process of claim 9 , wherein, after removal of organic solvent and water, the purified polyether polyol has a 2M2P (2-Methyl-2-Pentenal) content of no more than 5 ppm, based on total weight of the polyether polyol, as measured by Headspace Gas Chromatography and Mass Spectrometry (HS GC-MS).

12 . The process of claim 9 , wherein, after removal of organic solvent and water, the purified polyether polyol has a 2M2P (2-Methyl-2-Pentenal) content of no more than 1 ppm, based on total weight of the polyether polyol, as measured by Headspace Gas Chromatography and Mass Spectrometry (HS GC-MS).

13 . The process of claim 12 , wherein the purified polyether polyol has an acid number of no more than 0.1 mg KOH/g measured according to ASTM D7253-16.

14 . The process of claim 12 , wherein the purified polyether polyol has an alkalinity, determined by visual titration, of no more than 0.2 meq/kg.

15 . A process for producing a polyether polyol, comprising: (a) adding an alkylene oxide onto an H-functional starter in the presence of an alkali metal catalyst to produce an alkali metal-containing crude polyol comprising a mixture comprising the polyether polyol and alkali metal ions; (b) passing the mixture through a first bed comprising a cation exchange resin comprising carboxylic acid and/or phosphonic acid groups to remove alkali metal ions from the mixture; and (c) passing the product of step (b) through a second bed comprising an anion exchange resin comprising quaternary ammonium groups and a cation exchange resin comprising carboxylic acid and/or phosphonic acid groups to thereby produce a purified polyether polyol, wherein the first bed and the second bed are each free of a cation exchange resin that comprises sulfonic acid groups.

16 . The process of claim 13 , wherein the polyether polyol has a hydroxyl number of no more than 56 mg KOH/gram, measured according to ASTM D4274-16.

17 . The process of claim 15 , wherein cation exchange resin that comprises sulfonic acid groups is present in an amount of no more than 1% by weight, based on the total weight of ion exchange resin used in each bed.

18 . The process of claim 15 , further comprising removing organic solvent and water from the purified polyether polyol.

19 . The process of claim 18 , wherein, after removal of organic solvent and water, the purified polyether polyol has a 2M2P (2-Methyl-2-Pentenal) content of no more than 5 ppm, based on total weight of the polyether polyol, as measured by Headspace Gas Chromatography and Mass Spectrometry (HS GC-MS).

20 . The process of claim 18 , wherein, after removal of organic solvent and water, the purified polyether polyol has a 2M2P (2-Methyl-2-Pentenal) content of no more than 1 ppm, based on total weight of the polyether polyol, as measured by Headspace Gas Chromatography and Mass Spectrometry (HS GC-MS).

Assignees

• Covestro Llc

Inventors

• Wagner Daniel R
• Neal Brian L

Classifications

• C08G18/48

  Polyethers · CPC title

• B01J41/10

  Inorganic material · CPC title

• B01J39/12

  Compounds containing phosphorus · CPC title

• B01D3/10

  Vacuum distillation (B01D3/12 takes precedence) · CPC title

• C02F1/42

  by ion-exchange (ion-exchange in general B01J) · CPC title