Process for preparing polyether alcohols

Patent metadata

Field	Value
Publication number	US-9120731-B2
Application number	US-201113813300-A
Country	US
Kind code	B2
Filing date	Aug 8, 2011
Priority date	Aug 9, 2010
Publication date	Sep 1, 2015
Grant date	Sep 1, 2015

Abstract

What is proposed is a process for preparing polyether alcohols by conversion of the following reactants: a) one or more alkylene oxides and optionally carbon dioxide and b) one or more H-functional starter substances, in the presence of a catalyst, to form a liquid reaction mixture, in a reaction unit ( 1 ), which is characterized in that the reaction unit ( 1 ) has internals ( 2 ) which form a multitude of microstructured flow channels which bring about multiple splitting of the liquid reaction mixture into component flow paths and recombination thereof in altered arrangement, the multiple splitting and recombination being repeated several times and the microstructured flow channels having a characteristic dimension which is defined as the greatest possible distance of any particle in the liquid reaction mixture from the wall of a flow channel closest to the particle, in the range from 20 to 10 000 μm, the result being that the flow profile of the liquid reaction mixture approximates to ideal plug flow as a result of the microstructured flow channels.

First claim

The invention claimed is:

1. A process for preparing polyether alcohols, the process comprising:
reacting
a) one or more alkylene oxides and optionally carbon dioxide, and
b) one or more H-functional starter substances,
in the presence of a catalyst, to form a liquid reaction mixture in a reaction unit,
wherein:
the reaction unit has internals which form a multiplicity of microstructured flow channels, which effect multiple splitting of the liquid reaction mixture into component flow pathways and renewed recombining thereof in altered arrangement,
the multiple splitting and renewed recombining are repeated 10 to 10,000 times, and
the microstructured flow channels having a characteristic dimension, defined as the greatest possible distance of any particle in the liquid reaction mixture to the flow channel wall closest to the particle, in a range of from 20 to 10,000 μm, so that a flow profile of the liquid reaction mixture through the microstructured flow channels is approximate to an ideal plug flow and away from a parabolic flow profile.

2. The process according to claim 1 , wherein some or all of a) and b) and optionally the catalyst are premixed in a mixer outside the reaction unit at a temperature lower than a temperature of reacting.

3. The process according to claim 1 , wherein the characteristic dimension of the microstructured flow channels is in a range of from 40 to 6000 μm.

4. The process according to claim 1 , wherein:
the internals are reaction plates, with two or more of the reaction plates arranged in parallel above one another and in a principal direction of flow through the reactor unit to form a reactor module,
the reaction unit comprises one or more reactor modules,
each reaction plate comprises a multiplicity of slots of constant or variable width arranged parallel to one another and at a nonzero angle a to the principal direction of flow,
an immediately adjacent reaction plate comprises a multiplicity of geometrically identical slots arranged at an angle of −α,
the slots of all reaction plates are arranged one above another forming a flow channel,
a) and b) are fed into the flow channel and a product mixture is removed from the flow channel,
a separator sheet arranged parallel to each reaction plate and on both sides of the reactor module completely closes off the slots, and
a heat transfer medium circulates through one or more cooling or heating plates adjacent to each separator sheet on a side of the separator sheet opposite to the reactor module.

5. The process according to claim 4 , wherein the angle αis 45°.

6. The process according to claim 4 , wherein:
two or more cooling or heating plates are provided, with each cooling or heating plate comprising a multiplicity of slots of constant or variable width that are arranged parallel to one another and at the angle a to the principal direction of flow of the heat transfer medium,
an immediately adjacent cooling or heating plate comprises a multiplicity of geometrically identical slots arranged at the angle of −α, and
the slots of all the cooling or heating plates arranged one above another form a flow channel, with the heat transfer medium being fed into one end of the flow channel and removed at the other end of the flow channel.

7. The process according to claim 1 , wherein the reaction of the one or more alkylene oxides takes place with addition of a comonomer or carbon dioxide, wherein the comonomer is a cyclic anhydride, a lactone, or any mixture thereof.

8. The process of claim 1 ,
wherein:
i) the reaction occurs in block operation with two or more reaction units,
ii) a) and b) are mixed in a ratio and fed to a first reaction unit to give a first reaction mixture,
iii) the first reaction mixture is optionally cooled or heated after leaving the first reaction unit,
iv) one or more additional materials either the same as or different from a) and b) are mixed in a mixing ratio different from the ratio in ii) to give a second reaction mixture, which is fed to a second reaction unit, and
v) the first and second reaction mixtures are fed to a third reaction unit, with iii) and iv) being repeated accordingly.

9. The process according to claim 2 , wherein:
the one or more alkylene oxides, and optionally the carbon dioxide, are firstly premixed with the catalyst in a first mixing step in the mixer, and
the one or more H functional starter substances are mixed in a second mixing step.

10. The process according to claim 1 , wherein a) are ethylene oxide, propylene oxide, butylene oxide, pentene oxide, glycidyl ether, hexene oxide, styrene oxide, carbon dioxide, or any mixtures thereof.

11. The process according to claim 1 , wherein the H functional starter substances are one or more alcohols having a functionality of from 1 to 8.

12. The process according to claim 11 , wherein
the alcohol having a functionality of 1 has the general formula R-OH, wherein R is a saturated or unsaturated alkyl, aryl, aralkyl or alkylaryl radical comprising 1 to 60.

13. The process according to claim 11 , wherein the alcohols having a functionality of from 2 to 8 are ethylene glycol, propylene glycol, glycerol, trimethylolpropane, pentaerythritol, or any mixture thereof.

14. The process according to claim 1 , wherein the catalyst is a multimetal cyanide complex catalyst.

15. The process according to claim 1 , wherein the catalyst is potassium hydroxide, alkali metal alkoxide, or amine.

16. The process according to claim 14 , wherein the multimetal cyanide complex catalyst is recovered by membrane crossflow filtration of a reaction discharge from the reaction unit and is recycled to the process.

17. The process according to claim 1 , wherein the characteristic dimension of the microstructured flow channels is in a range of from 50 to 4000 μm.

18. The process according to claim 11 , wherein the alcohol having a functionality of 1 is methanol, butanol, hexanol, heptanol, octanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, butenol, hexenol, heptenol, octenol, nonenol, decenol, undecenol, vinyl alcohol, allyl alcohol, geraniol, linalool, citronellol, phenol, nonylphenol, or any mixture thereof.

Assignees

• Loeffler Achim
• Stoesser Michael
• Loth Wolfgang
• Boehling Ralf
• Zarbakhsh Sirus
• Basf Se

Inventors

• Loeffler Achim
• Stoesser Michael
• Loth Wolfgang
• Boehling Ralf
• Zarbakhsh Sirus

Classifications

• C07C41/02 Primary

  from oxiranes · CPC title

• C08G65/2609 Primary

  containing aliphatic hydroxyl groups · CPC title

• C08G65/2696 Primary

  characterised by the process or apparatus used · CPC title

• C08G67/02

  Copolymers of carbon monoxide and aliphatic unsaturated compounds · CPC title

• C08G65/2663

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