JP3229680B2 - Method for producing polyether polyol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for producing a polyether polyol.

[0002]

2. Description of the Related Art Polyether polyols are synthesized by ring-opening addition polymerization of an alkylene oxide using a compound having an active hydrogen capable of reacting with an alkylene oxide such as a hydroxyl group, an amino group, a mercapto group or a carboxyl group as an initiator. A compound having an ether bond in the molecular chain and a hydroxyl group at the terminal. Particularly, a polyether polyol having two or more terminal hydroxyl groups on average is one of the main raw material compounds in the polyurethane industry and the like. Also,
It is an industrially important compound that can be widely used for surfactants, lubricating oils and other uses.

Conventionally, polyether polyols have been produced.
As a method, in the presence of an alkali catalyst such as potassium hydroxide
The method of reacting an alkylene oxide with
ing. This production method using an alkali catalyst improves the reaction rate.
In order to increase the temperature, generally raise the reaction temperature, catalyst
Increasing the volume and increasing the alkylene oxide concentration in the reactor
Methods such as increasing can be used. However,
Propyleneoxy, the main raw material for reether polyols
Changes in these conditions increase the rate of isomerization
And polyether monool having an unsaturated bond at the terminal
Increase in the production of, for example, industrial chemistry magazine,6
9, 501 (1966). Therefore, conventionally, unsaturated
Side reaction of the formation of polyether monools with bonds
Use of an alkali catalyst alone without increasing the reaction
It was not possible to increase the reaction rate by the production method.
The increase in polyether monools having unsaturated bonds,
It is known that it reduces various physical properties of polyurethane resin.
Is not preferred.

On the other hand, when polymerizing alkylene oxide using an alkali catalyst, a method of increasing the reaction rate by adding a co-catalyst is also known. For example, Acta
Polymerica 35 , 28 (1984) describes that when polymerizing propylene oxide with an alkali metal compound, the addition of a crown ether can improve the reaction rate without increasing the number of monools having an unsaturated bond. However, crown ethers are problematic in that they are very expensive and their toxicity, and are not satisfactory as an industrial production method.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a method for polymerizing an alkylene oxide using an alkali catalyst, particularly when polymerizing propylene oxide, without increasing the production of polyether monool having an unsaturated bond. An object of the present invention is to provide a method for adding a cocatalyst which is inexpensive and easy to handle as a method for improving the reaction rate.

[0006]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, when polymerizing alkylene oxide using an anionic polymerization catalyst such as an alkali catalyst, particularly polymerizing propylene oxide. It has been found that by adding phosphine oxides as a co-catalyst, the reaction rate is improved without increasing the production of polyether monool having an unsaturated bond, and as a result, a polyether polyol can be efficiently produced. Thus, the present invention has been completed. .

That is, the present invention is as follows (1) to (3). (1) A method for producing a polyether polyol, comprising using a phosphine oxide as a cocatalyst in polymerizing an alkylene oxide with a catalyst arbitrarily selected from the group consisting of alkali metal compounds. (2) The method according to (1), wherein the catalyst for polymerizing the alkylene oxide is an alkali metal hydroxide. (3) The method according to (1), wherein the alkylene oxide is propylene oxide alone or a combination of propylene oxide and ethylene oxide.

In the present invention, the phosphine oxides used as cocatalysts include triphenylphosphine oxide, tri-n-octylphosphine oxide, tri-n-
Butyl phosphine oxide and the like, these alone,
Alternatively, two or more kinds can be used in combination. Also, polyphosphine oxide can be used.

As the catalyst, compounds such as lithium, sodium, potassium, rubidium, cesium and the like can be used, but an alkali metal hydroxide is preferred, and potassium hydroxide is particularly preferred.

Although the amount of the phosphine oxide is not particularly limited, it is preferably at least 1 mol%, more preferably 5 to 100 mol%, based on a catalyst arbitrarily selected from the group consisting of alkali metal compounds. It is. The amount of the catalyst used is not particularly limited, either, but is suitably 1 to 50 mol% based on the functional group of the active hydrogen compound as the initiator.

The active hydrogen compound serving as an initiator is a compound having a functional group to which an alkylene oxide can be added, such as a hydroxyl group, an amino group, a mercapto group, and a carboxyl group. In order to produce a polyether polyol which is a raw material of polyurethane, an initiator requires at least two active hydrogens, and accordingly, polyhydric alcohols and amines are suitable as the initiator. Also, the polyether polyol itself can be used as an initiator for a higher molecular weight polyether polyol. The hydroxyl value of the polyether polyol produced by the method of the present invention is not particularly limited, but as a polyurethane raw material, 10 to 400 mgKOH /
g is preferred.

The reaction is preferably performed under conventional conditions, but is not limited thereto. For example, an alkali metal compound catalyst is usually used for a functional group of an initiator.
Alkylene oxide is added at a temperature of 80 to 180 ° C. under normal pressure or under a pressure of 5 kgf / cm ² G or less. In the present invention, these conditions can be used as they are, and of course, the reaction can be carried out under milder or more severe conditions.

[0013]

The present invention will be described below with reference to examples. Parts in Examples and Comparative Examples represent parts by weight.

Example 1 To 300 parts of a polyether polyol having a molecular weight of 1000 obtained by adding propylene oxide to propylene glycol, 7 parts of potassium hydroxide dissolved in 20 parts of water was added, and the mixture was charged into a 2 L autoclave and heated at 100 ° C. 10mmHg while heating up
The mixture was dehydrated under reduced pressure for 1.5 hours. After charging the autoclave with 33.3 parts of triphenylphosphine oxide, the internal pressure of the autoclave was reduced to 0 kgf / cm ² G by nitrogen replacement, and the autoclave was heated to 110 to 115 ° C.
While controlling the internal temperature of the autoclave, 1200 parts of propylene oxide was charged over 3 hours. Further, an aging reaction was performed for 1.75 hours while maintaining the temperature until no decrease in internal pressure was observed. Total reaction time was 4.75 hours.
After completion of the reaction, the alkali was neutralized with phosphoric acid, dehydrated under a reduced pressure of 10 mmHg for 2 hours, and filtered using a filter paper to give a hydroxyl value of 3
A polyether polyol having 2.3 mg KOH / g and a total degree of unsaturation of 0.056 meq / g was obtained.

Example 2 Instead of triphenylphosphine oxide, 46.4 parts of tri-n-octylphosphine oxide was used, and
A hydroxyl value was obtained in the same manner as in Example 1 except that the hydroxyl value was
A polyether polyol having 33.0 mg KOH / g and a total degree of unsaturation of 0.058 meq / g was obtained. Total reaction time was 5 hours.

Comparative Example 1 The same operation as in Example 1 was carried out except that the aging reaction was carried out for 2.25 hours without using phosphine oxides as a cocatalyst.
A polyether polyol having a hydroxyl value of 33.1 mgKOH / g and a total degree of unsaturation of 0.070 meq / g was obtained. Total reaction time was 5.25 hours.

From a comparison between Examples 1 and 2 and Comparative Example 1,
It can be seen that the use of phosphine oxides as cocatalysts can increase the reaction rate without increasing the total unsaturation.

[0018]

The present invention provides a method for adding a phosphine oxide as a co-catalyst when a polyether polyol is produced by polymerizing an alkylene oxide using an alkali metal compound as a catalyst. Particularly effective in improving the production efficiency of ether polyol.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-174091 (JP, A) JP-B-47-896 (JP, B1) JP-B-47-404 (JP, B1) (58) Field (Int.Cl. ⁷ , DB name) C08G 65/00-65/48 WPI / L

Claims (3)

(57) [Claims] 1. A method for producing a polyether polyol, comprising using a phosphine oxide as a cocatalyst in polymerizing an alkylene oxide with a catalyst arbitrarily selected from the group consisting of alkali metal compounds. 2. The method according to claim 1, wherein the catalyst for polymerizing the alkylene oxide is an alkali metal hydroxide. 3. The method according to claim 1, wherein the alkylene oxide is propylene oxide alone or a combination of propylene oxide and ethylene oxide.