Method for producing high molecular weight polyoxyalkylene polyols

Patent metadata

Field	Value
Publication number	US-10457775-B2
Application number	US-201615754491-A
Country	US
Kind code	B2
Filing date	Aug 23, 2016
Priority date	Aug 26, 2015
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

The invention relates to an efficient method for producing polyoxyalkylene polyols with equivalent molar masses between 9500 and 23000 g/mol from one or more H-functional starter compounds, and one or more alkylene oxides in the presence of a double metal cyanide catalyst, characterized in that the alkylene oxide metering rate is reduced once a calculated equivalent molar mass of between 8000 and 9500 g/mol is reached.

First claim

The invention claimed is:

1. A process for preparing a polyoxyalkylene polyol comprising reacting at least one H-functional starter compound with at least one alkylene oxide in the presence of a double metal cyanide catalyst in a reactor, by supplying the reactor continuously or discontinuously with the at least one alkylene oxide from a time t 1 until a time t 3 , and by previously commencing supply of the reactor with a portion of the total amount of the at least one alkylene oxide to be fed in for preparation of the desired polyoxyalkylene polyol from an earlier time to
wherein
from a time t 2 the mean metering rate r AO with which the at least one alkylene oxide is supplied to the reactor is not more than 42 h −1 ,
in which t 3 ≥t 2 ≥t 1 , and

r
AO

=

n
AO

n
OH

·
Δ

⁢

⁢
t

·

OH
⁢
N

target

/

(

mg
KOH

·

g

-
1

)

,

⁢

wherein
Δt: represents a period of time from t 2 until the time of ending of the alkylene oxide addition (t 3 ) in h,
n AO : represents the molar amount n of alkylene oxide in mol added in total over the period of time Δt,
n OH : represents the total molar amount n of hydroxyl groups in the starter compound used in mol,

OH
⁢
N

target

=

m
S

·

OH
⁢
N

S

m
R

;

OHN S : represents the hydroxyl number of the at least one starter compound in mg KOH/g,
m S : represents the total mass of the at least one starter compound used in g,
m R : represents the total mass of all reactants supplied to the reactor after ending of the alkylene oxide addition in g,

where the time t 2 is chosen such that the polyoxyalkylene polyol present in the reactor at this time has a calculated equivalent molar mass M(t 2 ) equiv. calc. in the range from 8000 g·mol −1 to 9500 g·mol −1 ,
where, in addition, the at least one alkylene oxide from the time t 1 and
at least until the time corresponding to the attainment of a calculated equivalent molar mass M(t) equiv. calc. of 8000 g·mol −1 and
at most until the time corresponding to the attainment of a calculated equivalent molar mass M(t) equiv. calc. of 9500 g·mol −1

is supplied to the reactor so as to attain a total alkylene oxide metering time, defined as the period of time Δt 30 =t 3 −t 0 , of 0.5 h to 13 h,
where

M
⁡

(
t
)

equiv
.

calc
.

=

m
R
t

m
S

·

OH
⁢
N

S

·

(

56100
⁢

⁢

mg
KOH

·

mol

-
1

)

,

in which
m R t : represents the total mass of all reactants supplied to the reactor up to a given time t in g.

2. The process as claimed in claim 1 , wherein the polyoxyalkylene polyol, after the total alkylene oxide metering time has elapsed, has a calculated equivalent molar mass of 9500 g·mol −1 to 23,000 g·mol −1 .

3. The process as claimed in claim 1 , wherein an alkylene oxide portion of up to 20% by mass of alkylene oxide, based on the amount of the at least one H-functional starter compound used, is supplied from a time to until a time not later than t 1 .

4. The process as claimed in claim 1 , comprising
(α) initially charging the reactor with the double metal cyanide catalyst and the at least one H-functional starter compound and, at a temperature of 60° C. to 160° C., introducing an inert gas into the mixture of double metal cyanide catalyst and the at least one H-functional starter compound, and simultaneously establishing a reduced pressure of 5 mbar to 500 mbar (absolute) by removing the inert gas (“stripping”),
(β) then feeding the at least one alkylene oxide into the mixture from step (α) in the reactor (“polymerization”), wherein commencing the su

Assignees

• Covestro Deutschland Ag

Inventors

• Lorenz Klaus
• Steinlein Christian
• Zwick Horst
• Bodenmüller Markus
• Eckelmann Stephan
• Baer Friedhelm

Classifications

• C08G65/2696

  characterised by the process or apparatus used · CPC title

• C08G65/2663 Primary

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

• C08G65/2606 Primary

  containing hydroxyl groups · CPC title

• C08G2650/24

  Polymeric initiators · CPC title

• C08G2650/58

  Ethylene oxide or propylene oxide copolymers, e.g. pluronics · CPC title