Method for producing polyether carbonate polyols

Patent metadata

Field	Value
Publication number	US-10836858-B2
Application number	US-201716309979-A
Country	US
Kind code	B2
Filing date	Jun 20, 2017
Priority date	Jun 22, 2016
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

The invention relates to a method for producing polyether carbonate polyols by adding alkylene oxides and carbon dioxide to an H-functional starter substance in the presence of a double metal cyanide (DMC) catalyst or in the presence of a metal complex catalyst based on the metals zinc and/or cobalt, wherein (γ) alkylene oxide and carbon dioxide are added to an H-functional starter substance in a reactor with a total pressure (absolute) of 5 to 120 bar in the presence of a double metal cyanide catalyst or in the presence of a metal complex catalyst based on the metals zinc and/or cobalt, and a reaction mixture containing the polyether carbonate polyol is obtained, (δ) the reaction mixture obtained in step (γ) remains in the reactor or is optionally continuously transferred to a downstream reactor at a starting total pressure (absolute) of 5 to 120 bar, the content of free alkylene oxide in the reaction mixture being reduced in the course of a downstream reaction in each case, and the total pressure (absolute) can be reduced by up to 50% during the step (δ), and (ζ) the content of highly volatile components of the obtained reaction mixture is thermally reduced at a temperature of 80° C. to 200° C. The invention is characterized in that (ε) the reaction mixture resulting from step (δ) is brought to a total pressure (absolute) of ≤2.0 bar, preferably 0.5 bar to 2.0 bar, particularly preferably 0.9 bar to 1.1 bar, prior to step (ζ) and then left at a temperature of 80 to 180° C. for a dwell time of at least 0.5 h. After the dwell time has expired, 5 to 100 ppm of component K is added to the resulting mixture, component K being selected from at least one compound which contains a phosphorus-oxygen-hydrogen group.

First claim

The invention claimed is:

1. A process for preparing polyether carbonate polyols comprising adding an alkylene oxide and carbon dioxide onto an H-functional starter substance in the presence of a double metal cyanide (DMC) catalyst or in the presence of a metal complex catalyst based on the metals zinc and/or cobalt, wherein the process comprises
(γ) adding the alkylene oxide and carbon dioxide onto the H-functional starter substance in a reactor at a total (absolute) pressure of 5 to 120 bar in the presence of a double metal cyanide catalyst or in the presence of a metal complex catalyst based on the metals zinc and/or cobalt to obtain a reaction mixture comprising the polyether carbonate polyol,
(δ) allowing the reaction mixture comprising the polyether carbonate polyol obtained in step (γ) in the reactor or optionally transferring the reaction mixture continuously into a postreactor at an initial total (absolute) pressure of 5 to 120 bar, wherein the content of free alkylene oxide in the reaction mixture is reduced in each case by way of a postreaction, and wherein the total (absolute) pressure during step (δ) can decrease by up to 50%, and
(ζ) thermally reducing the content of readily volatile constituents in the reaction mixture obtained at a temperature of 80° C. to 200° C.,
wherein:

(ε) prior to step (ζ), the reaction mixture resulting from step (δ) is brought to a total (absolute) pressure of ≤2.0 bar and then held at a temperature of 80 to 180° C. for a residence time of at least 0.5 h, and after this residence time has elapsed, adding 5 to 100 ppm of component K to the resulting mixture, where component K comprises at least one compound containing a phosphorus-oxygen-hydrogen group.

2. The process as claimed in claim 1 , wherein, in step (ε), the reaction mixture is held at a temperature of 80 to 180° C. for a residence time of 1.0 h to 20 h, and after this residence time has elapsed, from 5 to 100 ppm of component K is added to the resulting mixture.

3. The process as claimed in claim 1 , wherein, in step (ε), the reaction mixture is held at a temperature of 80 to 180° C. for a residence time of 1.0 h to 20 h, and after this residence time has elapsed, from 5 to 75 ppm of component K is added to the resulting mixture.

4. The process as claimed in claim 1 , wherein, in step (ε), the reaction mixture is held at a temperature of 100 to 160° C. for a residence time of 1.0 h to 20 h, and after this residence time has elapsed, from 5 to 100 ppm of component K is added to the resulting mixture.

5. The process as claimed in claim 1 , wherein, in step (ε), the reaction mixture is held at a temperature of 100 to 160° C. for a residence time of 2.0 h to 10 h, and after this residence time has elapsed, from 5 to 75 ppm of component K is added to the resulting mixture.

6. The process as claimed in claim 1 , wherein component K, in addition to step (ε), is added during step (δ) at a free alkylene oxide content of 1 g/L to 10 g/L alkylene oxide.

7. The process as claimed in claim 1 , wherein prior to step (γ)
(β) adding a portion (based on the total amount of the alkylene oxides used in the activation and copolymerization) of alkylene oxide to a mixture of H-functional starter substance and DMC catalyst or to a mixture of suspension medium and DMC catalyst to activate the catalyst, wherein this addition of the portion of alkylene oxide can optionally be effected in the presence of CO 2 , and in each case awaiting the temperature peak (“hotspot”) that occurs owing to the subsequent exothermic chemical reaction and/or a pressure drop in the reactor, and wherein activation step (β) can also be effected repeatedly.

8. The process as claimed in claim 1 , wherein in a first step
(α) initially charging the H-functional starter substance or a suspension medium, and removing any water and/or other readily volatile compounds by elevated temperature and/or reduced pressure (“drying”), wherein the DMC catalyst is added to the H-functional starter substance or to the suspension medium before or after the drying.

9. The process as claimed in claim 1 , wherein in step (γ) alkylene oxide, H-functional starter substance and DMC catalyst are continuously metered into the reactor during the reaction in the presence of carbon dioxide and the resulting reaction mixture is continuously removed from the reactor.

10. The process as claimed in claim 1 , wherein component K comprises at least one of
phosphoric acid,
mono- and/or dialkyl esters of phosphoric acid,
mono- and/or diaryl esters of phosphoric acid,
mono- and/or dialkaryl esters of phosphoric acid,
(NH 4 ) 2 HPO 4 ,
phosphonic acid,
monoalkyl esters of phosphonic acid,
monoaryl esters of phosphonic acid,
monoalkaryl esters of phosphonic acid,
phosphorous acid,
mono- and/or dialkyl esters of phosphorous acid,
mono- and/or diaryl esters of phosphorous acid,
mono- and dialkaryl esters of phosphorous acid,
and
phosphinic acid.

11. The process as claimed in claim 1 , wherein component K comprises at least one of phosphoric acid, phosphonic acid, and phosphinic acid.

12. The process as claimed in claim 1 , wherein component K comprises phosphoric acid.

13. The process as claimed in claim 1 , wherein the H-functional starter substance comprises at least one of ethylene glycol, propylene glycol, propane-1,3-diol, butane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, 2-methylpropane-1,3-diol, neopentyl glycol, hexane-1,6-diol, octane-1,8-diol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol, sorbitol, polyether carbonate polyols having a molecular weight Mn in the range from 150 to 8000 g/mol with a functionality of 2 to 3, and polyether polyols having a molecular weight Mn in the range from 150 to 8000 g/mol with a functionality of 2 to 3.

14. The process as claimed in claim 1 , wherein in step (δ) the reaction mixture obtained in step (γ) is transferred continuously into a postreactor, wherein the postreactor is a tubular reactor.

15. The process as claimed in claim 1 , wherein in step (δ) the reaction mixture obtained in step (γ) is transferred continuously into a postreactor, wherein the content of free alkylene oxide is reduced to less than 0.5 g/L by way of postreaction.

Assignees

• Covestro Deutschland Ag

Inventors

• Hofmann Jörg
• Rauwald Urs
• Braun Stefanie
• Wohak Matthias
• Nefzger Hartmut
• Welsch Nicole
• Wolf Aurel
• Traving Michael
• Krueger Lars

Classifications

• C08G64/0208

  saturated · CPC title

• C08G65/2663 Primary

  Metal cyanide catalysts, i.e. DMC's · CPC title

• C08G64/34 Primary

  and cyclic ethers · CPC title

• C08G65/266

  Metallic elements not covered by group C08G65/2648 - C08G65/2645, or compounds thereof · CPC title

• C08G65/2606

  containing hydroxyl groups · CPC title