JPH06184297A - Production of polyether polyol - Google Patents

Abstract

PURPOSE:To improve the reaction rate at a low cost and obtain the subject compound having high quality by using a phosphine oxide as a cocatalyst in the polymerization of an alkylene oxide using an alkali metal compound as a catalyst. CONSTITUTION:The objective compound is produced by the polymerization of an alkylene oxide (preferably simple propylene oxide or a combination of propylene oxide and ethylene oxide) using preferably an alkali metal hydroxide (especially KOH) as a catalyst and a phosphine oxide (e.g. triphenylphosphine oxide and tri-n-octylphosphine oxide) as a cocatalyst. The amount of the cocatalyst is preferably 5-100mol% based on the catalyst.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an improved process for producing polyether polyols.

[0002]

2. Description of the Related Art Polyether polyol is synthesized by subjecting a compound having active hydrogen capable of reacting with an alkylene oxide such as a hydroxyl group, an amino group, a mercapto group, and a carboxyl group as an initiator to ring-opening addition polymerization of the alkylene oxide, A compound having an ether bond in the molecular chain and a hydroxyl group at the terminal. Particularly, a polyether polyol having an average of two or more terminal hydroxyl groups 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 applications.

Conventionally, as a method for producing a polyether polyol, a method of reacting an alkylene oxide in the presence of an alkali catalyst such as potassium hydroxide has been widely used. In order to improve the reaction rate in this production method using an alkali catalyst, methods such as increasing the reaction temperature, increasing the amount of catalyst, and increasing the alkylene oxide concentration in the reactor can generally be used. However, propylene oxide, which is the main raw material of the polyether polyol, increases the proportion of isomerization by changing these conditions and increases the production amount of the polyether monool having an unsaturated bond at the end, for example, industrial Chemical magazine, 6
9 , 501 (1966). Therefore, conventionally, it has been impossible to improve the reaction rate by a production method using an alkali catalyst alone without increasing the side reaction of forming a polyether monool having an unsaturated bond.
The increase in polyether monools with unsaturated bonds is
It is known to reduce various physical properties of the polyurethane resin, which is not preferable.

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

[0005]

The present invention is directed to the polymerization of alkylene oxides using an alkali catalyst, particularly to the polymerization of propylene oxide without increasing the production of polyether monool having unsaturated bonds. As a method for improving the reaction rate, an inexpensive and easy-to-handle co-catalyst is added.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that when an alkylene oxide is polymerized using an anionic polymerization catalyst such as an alkali catalyst, particularly propylene oxide is polymerized. It was found that the addition of phosphine oxides as a co-catalyst improves the reaction rate without increasing the production of polyether monool having an unsaturated bond, and as a result, the polyether polyol can be efficiently produced. 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, which comprises using phosphine oxides as a promoter when 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.

The phosphine oxides used as a cocatalyst in the present invention include triphenylphosphine oxide, tri-n-octylphosphine oxide and tri-n-.
Butylphosphine oxide and the like, these alone,
Alternatively, two or more kinds can be mixed and used. Also, polyphosphine oxide can be used.

As the catalyst, compounds such as lithium, sodium, potassium, rubidium and cesium can be used, but alkali metal hydroxides are preferable, and potassium hydroxide is particularly preferable.

The amount of phosphine oxides used is not particularly limited, but is preferably 1 mol% or more, and particularly preferably 5 to 100 mol% with respect to the catalyst arbitrarily selected from the group consisting of alkali metal compounds. Is. The amount of the catalyst used is also not particularly limited, but 1 to 50 mol% is appropriate with respect to 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 capable of adding an alkylene oxide 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 for polyurethane, the initiator requires at least two active hydrogens, and therefore polyhydric alcohols, amines and the like are suitable as the initiator. Further, the polyether polyol itself can be used as an initiator of 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, but not limited to, carried out under conventional conditions. For example, usually an alkali metal compound catalyst is based on the functional group of the initiator,
The alkylene oxide is added at 1 to 50 mol% and at a temperature of 80 to 180 ° C. under normal pressure or a pressure of 5 kgf / cm ² G or less. In the present invention, these conditions can be used as they are, or the reaction can be carried out under milder or more violent conditions.

[0013]

EXAMPLES The present invention will be described below with reference to examples. Parts in the 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 was dissolved in 20 parts of water, added, charged into a 2 L autoclave, and heated to 100 ° C. 10mmHg while heating up to
It was dehydrated for 1.5 h under reduced pressure. After charging 33.3 parts of triphenylphosphine oxide into the autoclave, the internal pressure of the autoclave was adjusted to 0 kgf / cm ² G by nitrogen substitution, and the temperature was 110-115 ℃.
1,200 parts of propylene oxide was charged over 3 hours while controlling the temperature inside the autoclave. Further, while maintaining the temperature, the aging reaction was carried out for 1.75 hours until no decrease in the internal pressure was observed. The total reaction time was 4.75 hours.
After the reaction was completed, the alkali was neutralized with phosphoric acid, dehydrated under reduced pressure of 10 mmHg for 2 hours, and filtered with filter paper to give a hydroxyl value of 3
A polyether polyol having 2.3 mgKOH / g and a total degree of unsaturation of 0.056 meq / g was obtained.

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

Comparative Example 1 By the same procedure as in Example 1 except that phosphine oxides were not used as a cocatalyst and the aging reaction was performed for 2.25 hours.
A polyether polyol having a hydroxyl value of 33.1 mg KOH / g and a total degree of unsaturation of 0.070 meq / g was obtained. The total reaction time was 5.25 hours.

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

[0018]

INDUSTRIAL APPLICABILITY The present invention provides a method for adding phosphine oxides as a co-catalyst when polymerizing alkylene oxide by using an alkali metal compound as a catalyst to produce a polyether polyol, and is used as a polyurethane raw material or the like. It exhibits a particularly excellent effect in improving the production efficiency of ether polyol.

Claims (3)

[Claims] 1. A process for producing a polyether polyol, which comprises using phosphine oxides as a co-catalyst when 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.