JPS63241028A - Production of polyether polyol - Google Patents

Abstract

PURPOSE:To obtain the title high-MW compound of a low impurity content, by reacting a polyhydroxy compound with an alkylene oxide in the presence of a specified alkali metal catalyst in an aprotic solvent. CONSTITUTION:An alkali metal catalyst (C) is obtained by reacting an alkali metal hydroxide (a) (e.g., KOH) with a cycloalkapolyene (b) (e.g., cyclopentadiene). A polyhydroxy compound (A) containing 4-8 OH groups and preferably being solid at room temperature (e.g., sucrose) is reacted with an alkylene oxide (B) (e.g., propylene oxide) at 100-160 deg.C under normal or elevated pressure in the presence of 1-10mol%, based on component A, compo nent C in an aprotic solvent (D), preferably, of the formula (wherein R1 is H or a 1-3C alkyl, R2-3 are each a 1-3C alkyl, R1 and R2 or R1 and R3 may be combined together to form a cyclic group), e.g., N-methylpyrrolidone, to obtain the title compound of an MW of 500-10,000 and an OH value of 10-650.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a novel method for producing polyether polyols.

(Prior art and its problems) Polyether polyol is formed by adding alkylene oxide to a polyhydroxy compound as a starting material, and is used for various purposes. Polyether polyols starting from functional polyhydroxy compounds have hydroxyl groups that can participate in three-dimensional reactions and are further useful. However, it is actually difficult to form polyether polyols starting from hydroxy compounds having 4 to 8 hydroxyl groups.

The polymerization reaction for forming a polyether polyol is usually carried out in a solution because it is easy to control the reaction, but there are few solvents that can dissolve all the substances necessary for the reaction and are inert to the polymerization reaction.

Canadian Patent No. 1,118,417 proposes the use of hydrophilic solvents such as N-methylpyrrolidone and N-methylacetamide in the formation reaction of polyether polyols. However, in the case of this patent, an amine-based catalyst is used, so the reaction is slow and the molecular weight is 900-1200.
and high molecular weight polymers are difficult to obtain.

JP-A No. 58-15933 discloses that an alkali metal hydroxide is used as a catalyst to react once in an aqueous solution to form a low molecular weight nucleus, which is further chain-extended in a second step. There is. However, since water is used as a solvent, a side reaction product between water and alkylene oxide is generated, which is extremely difficult to completely remove.

(Contents of the Invention) The present inventors have discovered that by using a special alkali metal catalyst, a useful polyether polyol having a higher molecular weight than that disclosed in the Canadian patent can be obtained.

That is, the present invention provides a polyether characterized by reacting a polyhydroxy compound and an alkylene oxide in an aprotic solvent in the presence of an alkali metal catalyst obtained by the reaction of an alkali metal hydroxide and a cycloalkapolyene. Provides a method for producing polyol.

Alkali metal hydroxides have high catalytic activity and are advantageous catalysts for the formation of polyether polyols.

However, this hydroxide is not soluble in the aprotic solvents used in the invention, especially N-methylpyrrolidone.

In the present invention, the alkali metal hydroxide is made into a form that can be dissolved in an aprotic solvent. For example, when potassium hydroxide and cyclopentadiene are used, the following reaction proceeds.

(A) This compound (A) is a solid and exhibits strong alkalinity when dissolved in an aprotic solvent such as N-methylpyrrolidone.

The alkali metal catalyst used in the production method of the present invention is obtained by reacting an alkali metal hydroxide with a cycloalkapolyene. This reaction usually occurs by mixing the two, but may be heated if necessary. Examples of alkali metal hydroxides include potassium hydroxide, sodium hydroxide, lithium hydroxide, rubidium hydroxide, and the like. Preferred are sodium hydroxide and potassium hydroxide.

Cycloalkapolyenes are usually those with an unsaturated group inside the ring, such as cyclopentadiene, cyclooctadiene, cyclododecatriene, etc., but those with an unsaturated group outside the ring, such as methylene vinyl cyclopentane, are also suitable. It is included in the cycloalkapolyene of the present invention.

A polyether polyol formation reaction is carried out in the presence of the alkali catalyst obtained by the above reaction. The reaction is carried out in an aprotic solvent. The use of solvents other than aprotic solvents is not preferred because side reactants are produced by reaction with the alkylene oxide. Preferably, the aprotic solvent has the following formula: OR.

R, -C-N (I) [wherein,
R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms, R7 or R3 are the same or different alkyl groups having 1 to 3 carbon atoms, and R1 and R2 or R1 and R3 may form a cyclic group. ” A typical example of an aprotic solvent that satisfies formula (1) is N.
-Methylpyrrolidone, dimethylacetamide, dimethylformamide and the like. Most preferred is N-methylpyrrolidone. Examples of aprotic solvents other than those of formula (I) include dimethyl sulfoxide, dimethylacetamide, dimethylformamide, and the like. The amount of the aprotic solvent used is 5 to 70% by weight, preferably 10 to 50% by weight, based on the total amount of the polymerization solution. Although the above upper limit may be used, it takes time to remove the solvent.

The polyhydroxy compound used in the present invention is preferably one that is solid at room temperature, but it may of course be applied to diols, triols, etc. that are liquid at room temperature.

Examples of polyhydroxy compounds that can be used are diols, such as ethylene glycol, dipropylene glycol, 1,4-butanediol, propylene glycol,
diethylene glycol, etc.; triols, such as trimethylolpropane, glycerol, etc.; tetraol, etc.
Examples include pentaerythritol: hexaols, such as D-turu, bitol, dipentaerythritol, and dioctaols, such as sucrose and lactose. Sucrose is most preferred due to its high organoleptic properties and low cost.

Any known alkylene oxide may be used. Examples of alkylene oxides include ethylene oxide, 1,2-propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, and the like. Most preferred are ethylene oxide and propylene oxide. If water is contained in the alkylene oxide, a side reaction will occur, so it may be removed by a known method.

The amount of alkylene oxide added varies greatly depending on the chain length, ie, molecular weight, or OH value of the polyether polyol. The preferred molecular weight of the polyether polyol is 500 to t.
o, o o o, preferably 700 to 8,000, and the OH value is 10 to 650, preferably 15 to 300. Therefore, polyalkylene oxide is added within this range.

The polymerization reaction is carried out by dropping or blowing the alkylene oxide into a heated aprotic solvent (containing the polyhydroxy compound and the alkali catalyst obtained by the above reaction) under normal pressure or increased pressure. The reaction temperature is usually 10
The temperature is 0 to 160°C, preferably 110 to 150°C. 1
If the temperature is below 00°C, the polymerization reaction will be slow, but side reactions will be suppressed. In other words, a product retaining a high number of functional groups can be obtained. Therefore, when a polymer with a high number of functional groups is required, it is meaningful to polymerize under pressure and heat at a temperature of 100°C or less, particularly 70 to 95°C. When the reaction temperature exceeds 160° C., side reactions in which terminal hydroxyl groups become unsaturated groups become significant.

When the unsaturated group forming reaction occurs, at the same time, the number of functional groups in the product is significantly lost. Unreacted monomers are collected and used again in the reaction.

After the polymerization reaction is completed, the catalyst is removed using an ion exchange resin substituted with the previously used aprotic solvent, and then the solvent is removed for purification.

(Effects of the Invention) The polyether polyol of the present invention is polymerized using a specific alkali catalyst, and a high molecular weight polymer can also be obtained from a highly functional polyhydroxy compound, especially sucrose. Furthermore, since a solvent that can react with alkylene oxide such as water is not used, side reaction products are less likely to be mixed in as impurities.

Furthermore, since the reaction is carried out using a hydrophilic organic solvent, purification can be easily carried out using an ion exchange resin. There is only one process and it is simplified. Furthermore, the molecular weight can be easily increased.

Multifunctional polyether polyols, especially sucrose-spaced polyether polyols, are highly advantageous for reaction with isocyanates to form the resulting polyurethanes. In the case of polyfunctional polyether polyols, thermal stability is extremely good. In the case of high molecular weight polyether polyols, the impact resistance of the resulting polyurethane is increased.

(Example) The present invention will be explained in more detail with reference to Examples.

Example 1 (Preparation of catalyst) 7.9 g of cyclopentadiene was added to 4.56 g of powdered KOH.
5 g was added, and the mixture was shaken and reacted at room temperature for about 1 hour. After the reaction, a dark brown solid (catalyst) was collected by filtration.

(Polymerization of polyol) 4.28 of the above catalyst was added to 500 mQ of N-methylpyrrolidone and dissolved with stirring. Next, sucrose 85.5
g was added thereto, and the temperature was raised while stirring to dissolve at about 90°C.

When the solution temperature reached about 130° C., 1600 mf of propylene oxide was added dropwise over about 4 hours. Approximately 430 mQ of unreacted propylene oxide was trapped. After the dropwise addition was completed, the mixture was cooled to room temperature and passed through an ion exchange resin substituted with N-methylpyrrolidone in advance. Then, using an evaporator, it was heated at about 120°C under a vacuum of 2 mmHg.
Time distillation was performed. The obtained polymer is a yellow-brown liquid with M
n=4. too, Mw/Mn=l, l2, OH value=
107, [C=C]=4. Omo1%/molof[O
H]. The above characteristic values are V manufactured by Hitachi, Ltd.
P O (V aper pressure osmo
sis) Measured with molecular pickle juice. Also, [C=C] is W
It was determined by the method of ij.

Example 2 4.0 g of the catalyst obtained in the same manner as in Example 1 was added to 500 mf2 of N-methylpyrrolidone and dissolved with stirring.

Subsequently, 68 g of pentaerythritol was added, the temperature was raised while stirring, and the mixture was dissolved at about 80°C. The solution is about 140℃
The temperature rose to . Next, propylene oxide about 150On++2
was added dropwise over about 3 hours. Approximately 300 mC of unreacted propylene oxide was recovered. After the dropwise addition was completed, the mixture was cooled to room temperature and passed through an ion exchange resin that had been substituted with N-methylpyrrolidone in advance. Subsequently, the solvent was removed by distillation using an evaporator at about 120° C. under a vacuum of 2 mm) Lg for 2 hours. The obtained polymer was yellowish brown and had Mn=21.
00, Mw/Mn=1, 10, ON value=10
6, [C=C]=2.5mol%/mol of [O
I had H'l.

Comparative Example 1 4.2 g of powdered KO was mixed with 500 m of N-methylpyrrolidone.
f2 and stirred. The solution had a yellowish brown color, but K
OI (was hardly dissolved. Next, sucrose 85
．． 5 g was added, and the temperature was raised to about 140°C while stirring. Sucrose melted at about 90°C, but KOH did not.
It remained granular. 500ml of propylene oxide as is
When 2 was added dropwise over about 2 hours, a large amount of precipitate was formed.

Example 3 N-methylpyrrolidone 5 in a 512 autoclave container
00m+2. 4.29% of the catalyst from Example 1 was added and stirred to dissolve. Subsequently, 85.5y of sucrose was added, and after sufficient nitrogen substitution, the temperature was raised with stirring (nitrogen pressure 2
kg/am. Sucrose melted at about 90°C. While maintaining the temperature at 95°C, 1,600 m (2) of propylene oxide was added dropwise using a high-pressure injection metering pump over a period of about 8 hours.
It took a while to react.

After the reaction, the reaction mixture was cooled to room temperature and passed through an ion exchange resin substituted with N-methylpyrrolidone to remove the catalyst. Next, use an evaporator to heat the temperature to about 120°C.
, 2 mm 1'l was distilled under vacuum for 2 hours. The obtained polymer was a yellowish brown liquid with M n -5,100, Mw/M
n=l, I3.0f-1 valence=84, [C=C]
=2.5mol%/mol of [OH].

Example 4 68 g of pentaerythritol was added in place of sucrose, and the pentaerythritol was dissolved at about 80°C. An experiment was carried out in the same manner as in Example 3, except that 1600 mC of propylene oxide was added dropwise over about 6 hours, and after the addition was completed, the reaction was further heated for 1 hour to terminate the reaction. The obtained polymer has Mn=2
,600, Mw/Mn=1.15, OH value=84,
[C=C-co 1.4mol1%/mol of [OI
(I had this.

Example 5 D-sorbitol 919 was added instead of sucrose,
D-sorbitol dissolved at about 70°C.

An experiment was carried out in the same manner as in Example 2, except that 1200 mQ of propylene oxide was added dropwise over about 4 hours, and after the dropwise addition was completed, the reaction was further heated for 1 hour to terminate the reaction. The obtained polymer had Mn=2.1001Mw/Mn=1°12, OH value=1
56, [C=C]=0.6mol%/mol of [
01~() existed.

Claims (1)

[Claims] 1. A polyhydroxy compound and an alkylene oxide are reacted in an aprotic solvent in the presence of an alkali metal catalyst obtained by the reaction of an alkali metal hydroxide and a cycloalkapolyene. A method for producing polyether polyol. 2. The method according to item 1, wherein the polyhydroxy compound has 4 to 8 hydroxyl groups. 3. The method according to item 2, wherein the polyhydroxy compound is sucrose. 4. The method according to item 1, wherein the alkali metal catalyst is a reaction product of potassium hydroxide and cyclopentadiene. 5. The method according to item 1, wherein the alkali metal catalyst is used in an amount of 1 to 10 mol % based on 1 mol of the polyhydroxy compound. 6. Aprotic solvents have the formula ▲ Numerical formulas, chemical formulas, tables, etc.
R_1 and R_2 or R_1 and R_3 may form a cyclic group. ] The manufacturing method according to item 1, which has the following. 7. No. 6 where the aprotic solvent is N-methylpyrrolidone
Manufacturing method described in section.