JPH07113060B2 - Polyether polyol manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a process for producing a novel high molecular weight polyether polyol.

(Prior Art) A high molecular weight polyether polyol is formed by adding a alkylene oxide to a polyhydroxy compound as a starting material and used for various purposes. Among these, the high molecular weight polyether polyol starting from a polyhydroxy compound having three or more functional groups has a hydroxyl group that can participate in a three-dimensional reaction, and is more useful. However, in spite of a simple reaction mechanism for producing this high molecular weight polyether polyol, it is quite difficult to obtain a high purity high molecular weight polyether polyol having a narrow molecular weight distribution. This is because impurities introduced at various stages of production or side reactions other than the main reaction occur to generate new initiator compounds and the like.

(Problems to be Solved by the Invention) An object of the present invention is to obtain a high molecular weight polyether polyol having high purity and a narrow molecular weight distribution.

(Means for Solving the Problems) As a result of studies to achieve the above object, the present inventors have completed the present invention.

That is, in the present invention, a polyhydroxy compound which is solid at room temperature is reacted with an alkylene oxide in the presence of a catalyst to form a liquid prepolymer, and the prepolymer is further mixed with an alkylene oxide in the presence of a catalyst. In the method for producing a polyether polyol, which comprises a second step of reacting to increase the molecular weight, the liquid prepolymer formed is purified, and then alkali metal alcoholate is added as a catalyst in the absence of a solvent to cause a reaction. A process for producing a high-molecular-weight polyether polyol (hereinafter referred to as a first process) is characterized in that after removing a molecular weight alcohol by distillation, an alkylene oxide is added and a reaction is carried out at 100 ° C or lower.

Further, in the present invention, a polyhydroxy compound which is solid at room temperature and an alkali metal alcoholate are reacted in a water-soluble organic solvent, and the produced low molecular weight alcohol is removed by distillation, and then reacted with an alkylene oxide at 100 ° C. or lower. A process for producing a high molecular weight polyether polyol (hereinafter, referred to as a second process) is provided.

Furthermore, the present invention is to react a low-molecular weight polyether polyol which is liquid at room temperature with an alkali metal alcoholate in a water-soluble organic solvent or an inorganic solvent, and after removing the low-molecular weight alcohol produced by distillation by an alkylene oxide. A method for producing a high molecular weight polyether polyol characterized by reacting (hereinafter, referred to as a third production method) is provided below.

First Production Method Although any of various methods may be used in the first step of the present invention, the prepolymer obtained in the first step is specifically a liquid polymer, preferably having a molecular weight of 4000 or less. If the molecular weight exceeds 4000, the amount of impurities increases and it becomes difficult to remove the impurities.

In the present invention, this liquid prepolymer is refined into a highly pure prepolymer. Various methods are used for purification. For example, methods such as distillation, filtration and extraction are preferably used. Vacuum distillation, which is a distillation under vacuum, is extremely suitable because it can remove trace impurities brought from various by-products and raw materials. Filtration is preferred if there is a precipitate. As for the method of this purification, various methods are combined depending on which method is used in the first step. Therefore, this method is well known to those skilled in the art.

In the present invention, the liquid prepolymer purified as described above is dissolved by adding an alkali metal alcoholate as a catalyst in the absence of a solvent and then adding an alkylene oxide and reacting at a temperature of 100 ° C. or lower. The alkali metal alcoholate is obtained by reacting an alkali metal with an alcohol (eg, ethanol, n-propanol, isopropanol, sec-butanol, t-butanol, etc.), and most preferably potassium tertiary butoxide. Alkali metal that can be used is sodium,
Examples thereof include potassium and lithium, but potassium is preferable.

In the method of the present invention, the above catalyst is first dissolved in the liquid polymer. Melting is carried out at a temperature of 150 ° C or lower, usually around 120 ° C. The amount of the catalyst used is 1 mol% or more, preferably 4 to 20 mol% based on the prepolymer. Dissolution may be carried out usually in an autoclave. When the catalyst is an alkali metal alcoholate, it reacts with the frepolymer to form a small amount of low molecular weight alcohol, but this low molecular weight alcohol causes impurities and is removed by distillation.

Examples of alkylene oxides that can be used include ethylene oxide, propylene oxide, butylene oxide and the like. The alkylene oxide may be continuously added dropwise or may be charged all at once. The addition reaction of alkylene oxide is carried out at a temperature of 100 ° C or lower. The reaction is usually performed in an autoclave. Above 100 ° C,
The purity of the product is reduced.

In the present invention, the alkylene oxide is preferably continuously added dropwise. It may be added all at once, but when it is added continuously, the molecular weight is easily increased and the reaction rate is not decreased.

In the first step of the present invention, the liquid prepolymer may be used by any method, but the polyhydroxy compound is preferably reacted in a hydrophilic organic solvent in the presence of a catalyst. Specific examples of the polyhydroxy compound include trimethylolpropane, glycerol, pentaerythritol, D-
Examples thereof include sorbitol, mannitol, dipentaerythritol, maltitol, sucrose, lactose, tripentaerythritol and the like. Examples of hydrophilic organic solvents include N-methylpyrrolidone, dimethylacetamide, dimethylformamide, dimethylsulfoxide, dioxane and the like. The catalyst that can be used may be an alkali metal alcoholate that can be used in the second step, but various catalysts conventionally used for prepolymerization of this type, such as triethylenediamine, triethylamine, triethanolamine, diethylenetriamine, N,
Amine-based catalysts such as N'-dimethyl-1,6 hexanediamine, N, N'-dimethyl-cyclohexylamine and 1,5-dimethyl-hexylamine, alkali metal hydroxides such as potassium hydroxide and sodium hydroxide Etc. may be used.
The amount of catalyst used is 1 for 1 mol of the polyhydroxy compound.
It is at least mol%, preferably from 4 to 20 mol%. The reaction temperature in the first step is generally not limited, and is in the range of 50 to 150 ° C.
It is preferably in the range of 70 to 100 ° C. A small amount of water may be present as a solvent in the first step, but the presence of water promotes the production of glycol as a side reaction product and is not preferred.

In the present invention, by refining the liquid prepolymer, deactivation of the catalyst used in the second step can be prevented and high molecular weight can be achieved. Further, in the second step, since the reaction is carried out in the absence of a solvent, it becomes easier to increase the molecular weight, and it is possible to prevent the reaction rate from decreasing. Further, the catalyst used in the second step has a long-lasting activity associated with the fact that it is in the absence of a solvent, and no reduction in the reaction rate is observed.

Second manufacturing method and third manufacturing method Since the second and third manufacturing methods are the same as the first manufacturing method,
Describe the difference.

The low molecular weight polyether polyol which is liquid at room temperature used in the third production method includes the liquid prepolymer of the first production method. The low molecular weight polyol is preferably one having a molecular weight of 500 or more, preferably 500 to 4,000, which is synthesized by the reaction of 1 mol of a polyhydroxy compound which is solid at room temperature and 3 mol or more of an alkylene oxide.

Conventionally, reaction with an alkylene oxide is carried out in the presence of a polyhydroxy compound, a catalyst and a solvent. The most serious problem in this method is that the by-products remain in the reaction system as they are, the molecular weight distribution of the obtained polyol becomes large, and the activity of the catalyst decreases, making it difficult to increase the molecular weight. In the second production method of the present invention, a polyhydroxy compound (solid) and a catalyst are dissolved and reacted in a water-soluble organic solvent to remove a low molecular alcohol by-product by distillation to synthesize a polyhydroxy compound salt (initiator salt). To do. (In the conventional method, since an alkali metal hydroxide is used as a catalyst, it is difficult to dissolve in a water-soluble organic solvent,
Therefore, the initiator salt cannot be synthesized. The reaction between the synthesized initiator salt and the alkylene oxide gives a high molecular weight polyol because there is no low molecular weight compound that inhibits the activity. In the third production method, the liquid polyether polyol is directly reacted with the metal-existing metal K which is a solvent-free or water-soluble organic solvent. By-product hydrogen is easily removed from the system.
Alternatively, an alkali metal alcoholate is used as a catalyst to react with the presence of a solvent-free or water-soluble organic solvent, and by-produced low molecular weight alcohol is removed by distillation to synthesize an initiator salt.

The reaction of the synthesized compound with the alkylene oxide gives a high molecular weight polyol, since there is no low molecular weight compound which inhibits the activity.

A low molecular weight alcohol produced by the reaction of a polyhydroxy compound that is solid at room temperature with an alkali metal alcoholate or a low molecular weight alcohol produced by the reaction of a low molecular weight polyether polyol with an alkali metal alcoholate is xylene, toluene, etc. in the system. It is easily removed by adding a small amount of and distilling under reflux.

The reaction with the alkylene oxide is carried out below 100 ° C.
Although the reaction activity decreases due to the reaction at a low temperature, a high molecular weight polyol having a narrow molecular weight distribution can be achieved relatively easily because there is no low molecular weight compound (alcohol or hydrogen) that inhibits the reaction activity. The reaction needs to be carried out under pressure in an autoclave. The reaction rate under normal pressure is slow. The reaction must be completely replaced with nitrogen.
In the presence of oxygen, an oxidative reaction occurs, chain decomposition occurs, and it becomes difficult to obtain a high molecular weight.

According to the method of the present invention, the catalyst can sufficiently perform its original function, and the factor of side reaction is removed,
Alternatively, it disappears, and a high molecular weight polyether polyol having a narrow molecular weight distribution can be obtained with high purity.

(Example) The present invention will be described in more detail based on an example. The invention should not be construed as limited to these examples.

Example 1 Synthesis of Prepolymer 1000 ml of N-methylpyrrolidone and 18.1 g of potassium t-butoxide were added to a 5 l autoclave and stirred at room temperature. Then, 342 g of sucrose was added, the atmosphere was replaced with nitrogen, and the temperature was raised with stirring. It melted at about 100 ° C. Next, 800 ml of propylene oxide was added dropwise using a high-pressure injection metering pump over about 2 hours. The reaction temperature was kept at 90-95 ° C. After completion of the dropwise addition, heating was continued for 1 hour to complete the reaction. The obtained liquid was a reddish brown transparent liquid.

Next, this polymer solution was subjected to vacuum distillation (2 mmHg) at 120 ° C. on an oil bath, and turbidity was generated. When it was filtered to remove turbidity, it was a transparent yellowish brown oil.

When this oil was analyzed, the molecular weight was Mn = 980, Mw / Mn = 1.
05, [C = C] = 0.10 mol% / mol of [OH].

Synthesis of Polyether Polyol 500 g of the obtained prepolymer was taken and 9.0 g of potassium t-butoxide was added and dissolved by heating. Next purified toluene 25
0 ml was added and the mixture was distilled at about 110 ° C. Toluene and t-BuOH produced from the catalyst were removed by distillation. After cooling to about 90 ° C., 3400 ml of propylene oxide was added dropwise over about 10 hours. After completion of dropping, the mixture was further heated for 1 hour in order to complete the reaction. After completion of the reaction, the catalyst was removed through an ion exchange resin or the like, and vacuum distillation was performed to obtain a yellow oily polymer. The properties of this polymer were as follows: Mn = 6200; Mw / Mn = 1.37; [C = C] = 4.7 mol% mol / of
[OH] Example 2 Synthesis of Prepolymer Synthesis was performed in the same manner as in Example 1 except that 136 g of pentaerythritol was used instead of 324 g of sucrose according to Example 1. The properties of the resulting prepolymer were as follows: Mn = 770; Mw / Mn = 1.04; [C = C] = 0.05 mol% / mol of
[OH] Synthesis of Polyether Polyol To 400 g of the above prepolymer, 7.0 g of potassium t-butoxide was added and dissolved. Next, 200 ml of purified toluene was added and the mixture was distilled at about 110 ° C. Toluene and t-butanol produced from the catalyst were removed by distillation. After cooling to about 90 ° C., 4500 ml of propylene oxide was added dropwise over about 17 hours. After the dropping was completed, the reaction and purification were carried out in the same manner as in Example 1 to obtain a yellow oily polymer. The properties of the polymer were as follows: Mn = 7200; Mw / Mn = 1.53; [C = C] = 10.3 mol% / mol o
f [OH] Example 3 Synthesis of Prepolymer A prepolymer was synthesized in the same manner as in Example 1 except that 182 g of D-sorbitol was used instead of 342 g of sucrose.
The properties of the resulting prepolymer were as follows: Mn = 820; Mw / Mn = 1.06; [C = C] = 0.07 mol% / mol of
[OH] Synthesis of polyether polyol To 400 g of the above prepolymer, 7.5 g of potassium t-butoxide was added and dissolved by heating. Next, 200 ml of purified toluene was added and the mixture was distilled at about 110 ° C. Toluene and t-BuOH produced from the catalyst were removed by distillation. After cooling to about 90 ℃,
4500 ml of propylene oxide was added dropwise over about 8 hours. After the dropwise addition, the reaction and purification were carried out in the same manner as in Example 1 to obtain a yellow oily polymer. The properties of the polymer were as follows: Mn = 7300; Mw / Mn = 1.47; [C = C] = 7.5 mol% / mol of
[OH] Comparative Example 1 1000 m of N-methylpyrrolidone was placed in a 10 l autoclave.
l, KOH (9 g) and pentaerythritol (135 g) were added, and the atmosphere was replaced with nitrogen. After cooling the temperature to 90 ° C., 7600 ml of propylene oxide was added dropwise using a high-pressure injection metering pump over about 15 hours. After completion of the dropwise addition, the reaction mixture was further heated for 1 hour in order to complete the reaction. After completion of the reaction, the catalyst was removed through an ion exchange resin, and vacuum distillation was performed to obtain a yellow oily polymer. The properties of the polymer were as follows: Mn = 5200; Mw / Mn = 1.46; [C = C] = 9.7 mol% / mol of
[OH] Example 4 In a 2 liter round bottom flask equipped with stirrer, condenser, thermometer, 11.2 g potassium tert-butoxide, 68 g
Of pentaerythritol and 500 ml of N-methylpyrrolidone were charged, and the temperature was raised to about 100 ° C. with stirring under nitrogen. The reaction mixture had a clear deep red color. The mixed solution was further heated to 120 ° C. and heated for about 2 hours. After heating, it was cooled to about 70 to 80 ° C. and distilled under reduced pressure of 8 mmHg. The by-product tert-butanol was collected. After cooling to room temperature, the obtained reaction product was transferred to an autoclave container equipped with a stirrer, a thermometer, and a cooling coil, 3500 g of propylene oxide was added, and the atmosphere was sufficiently replaced with nitrogen. While stirring, the temperature was slowly raised to about 90 ° C., and the reaction was performed by heating for about 22 hours. The polymer solution obtained after the reaction was purified to obtain a yellow oily polymer. The properties of the polymer were as follows:

Mn = 6665, Mw / Mn = 1.04 Unsaturated group = 3.65 × 10 ⁻⁵ mol / g Example 5 In the same manner as in Example 1, in a 2 liter round bottom flask, 4.48
g of potassium tert-butoxide, 360 g of pentaerythritol based prepolymer (Mn = 1800, Mw / Mn = 1.13)
Then, 400 ml of N-methylpyrrolidone was charged, and the temperature was raised to about 100 ° C. under nitrogen with stirring. The reaction mixture had a clear deep red color. 120 ° C for the mixed solution
The temperature was raised to about 2 hours. After heating, it was cooled to about 70 to 80 ° C. and distilled under reduced pressure of 8 mmHg. By-product tert-
After cooling to room temperature where butanol was collected, the obtained reaction product was transferred to a 5 liter autoclave container equipped with a stirrer, a thermometer, and a cooling coil in the same manner as in Example 1, and 1400 g of propylene oxide was added. Then, the nitrogen was sufficiently replaced. While stirring, slowly raise the temperature to 90 ± 5 ° C for approx. 15
The reaction was heated for a period of time. The polymer solution obtained after the reaction was purified to obtain a yellow oily polymer. The properties of the polymer were as follows:

Mn = 7630, Mw / Mn = 1.04 Unsaturated group = 4.15 × 10 ⁻⁵ mol / g Example 6 In the same manner as in Example 1, in a 2 liter round bottom flask, 3.50
g of potassium methoxide and 532 g of a pentaerythritol-based prepolymer (Mn = 2665, Mw / Mn = 1.15) were charged, and the mixture was heated to about 120 ° C. under nitrogen with stirring and heated for about 2 hours. The reaction mixture became brown and clear. After heating, it was cooled to about 70 to 80 ° C. and distilled under a reduced pressure of 8 mmHg. By-product methanol was collected. After cooling to room temperature, the obtained reaction product was transferred to a 5 liter autoclave container equipped with a stirrer, a thermometer, and a cooling coil in the same manner as in Example 1, and then 1400 g of propylene oxide was added and sufficiently replaced with nitrogen. did. While stirring, slowly raise the temperature to 90
The reaction was carried out by heating at ± 5 ° C for about 18 hours. The polymer solution obtained after the reaction was purified to obtain a yellow oily polymer. The properties of the polymer were as follows:

Mn = 8520, Mw / Mn = 1.05 Unsaturated group = 4.50 × 10 ⁻⁵ mol / g Example 7 In the same manner as in Example 1, in a 2 liter round bottom flask, 5.60
Then, g of potassium tert-butoxide, 85.6 g of sucrose and 400 ml of N-methylpyrrolidone were charged, and the temperature was raised to about 100 ° C. with stirring under nitrogen. The reaction mixture had a clear deep red color. The mixed solution was further heated to 120 ° C. and heated for about 2 hours. After heating, cool it down to about 70-80 ℃, 8mmHg
Distillation was performed under reduced pressure. The by-product tert-butanol was collected. After cooling to room temperature, the reaction product obtained was transferred to a 5 liter autoclave container equipped with a stirrer, a thermometer, and a cooling coil in the same manner as in Example 1, and 1500 g of propylene oxide was added, and nitrogen was added sufficiently. Was replaced. While stirring, the temperature was slowly raised and the reaction was carried out by heating at 90 ± 5 ° C. for about 12 hours. The polymer solution obtained after the reaction was purified to obtain a yellow oily polymer. The properties of the polymer were as follows:

Mn = 5342, Mw / Mn = 1.19 Unsaturated group = 3.17 × 10 ⁻⁵ mol / g Comparative Example 2 In a 5 liter autoclave vessel equipped with a stirrer, thermometer and cooling coil, 68 g of pentaerythritol,
5.6 g of potassium hydroxide and 500 ml of N-methylpyrrolidone as a solvent were added, and after sufficiently replacing with nitrogen, the temperature was raised to about 120 ° C. with stirring to heat and dissolve.
The solution was deep red transparent. After cooling to room temperature, add 3600 g of propylene oxide and replace with nitrogen.
The reaction was heated for a period of time. The polymer solution obtained after the reaction was purified to obtain a yellow oily polymer. The properties of the polymer were as follows: Mn = 5062, Mw / Mn = 1.43 Unsaturated group = 8.76 × 10 ⁻⁵ mol / g Comparative Example 3 5 liter autoclave vessel equipped with stirrer, thermometer and cooling coil 68g of pentaerythritol,
5.6 g of potassium hydroxide and 500 ml of N-methylpyrrolidone as a solvent were added, and after sufficiently replacing with nitrogen, the temperature was raised to about 120 ° C. with stirring to heat and dissolve.
The solution was deep red transparent. After cooling to room temperature, add 2800 g of propylene oxide and replace with nitrogen.
The reaction was heated for a period of time. The polymer solution obtained after the reaction was purified to obtain a yellow oily polymer. The properties of the polymer were as follows:

Mn = 4061, Mw / Mn = 1.27 Unsaturated group = 3.15 × 10 ⁻⁵ mol / g Comparative Example 4 85.6 g sucrose, 2.33 g in a 5 liter autoclave container equipped with a stirrer, thermometer, and cooling coil. After adding 400 ml of N-methylpyrrolidone as the potassium hydroxide and the solvent and sufficiently replacing with nitrogen, the temperature was raised to about 130 ° C. with stirring. The solution exhibited a dark red slurry. After cooling to room temperature, 1500 g of propylene oxide was added, and after purging with nitrogen, the reaction was carried out by heating at 90 ± 5 ° C. for about 20 hours. After the reaction, when cooled to room temperature, large lumps were formed.

Comparative Example 5 68 g of pentaerythritol, 5.6 g in a 2 liter round bottom Fracaco equipped with stirrer, thermometer and condenser.
Potassium hydroxide and 500 ml of N-methylpyrrolidone as a solvent, and after sufficiently replacing with nitrogen,
The temperature was raised to about 130 ° C. with stirring, and the mixture was heated and dissolved. The solution was deep red transparent. 2500 g of propylene oxide was added dropwise from a dropping funnel under nitrogen over 8 hours. The reaction was carried out at 135 ± 5 ° C. After the reaction, the obtained polymer solution was purified to obtain a yellow oily polymer. The properties of the polymer were as follows:

Mn = 3528, Mw / Mn = 1.34 Unsaturated group = 6.66 × 10 ^-5 mol / g

Claims (15)

[Claims] 1. A first step in which a polyhydroxy compound which is solid at room temperature is reacted with an alkylene oxide in the presence of a catalyst to form a liquid prepolymer, and the prepolymer is further mixed with an alkylene oxide in the presence of a catalyst. In the method for producing a polyether polyol, which comprises the second step of reacting to increase the molecular weight, after purifying the liquid prepolymer formed,
After removing the low molecular weight alcohol produced by the reaction by adding an alkali metal alcoholate as a catalyst in the absence of a solvent by distillation, adding alkylene oxide 10
A process for producing a high molecular weight polyether polyol, which is characterized by reacting at 0 ° C or lower. 2. The method for producing a polyether polyol according to claim 1, wherein the polyhydroxy compound which is solid at room temperature is sucrose, pentaerythritol or D-sorbitol. 3. The method for producing a polyether polyol according to claim 1, wherein the alkylene oxide is propylene oxide. 4. The method for producing a polyether polyol according to claim 1, wherein the alkali metal alcoholate is potassium t-butoxide. 5. The method according to claim 1, wherein the reaction at 100 ° C. or lower is carried out in an autoclave. 6. A polyhydroxy compound which is solid at room temperature and an alkali metal alcoholate are reacted in a water-soluble organic solvent,
A process for producing a high-molecular-weight polyether polyol, which comprises removing the produced low-molecular weight alcohol by distillation and then reacting it with an alkylene oxide at 100 ° C or lower. 7. The method according to claim 6, wherein the polyhydroxy compound is pentaerythritol, sucrose or sorbitol. 8. The alkali metal alcoholate is potassium t-.
The method according to claim 6, which is butoxide, potassium methoxide or potassium ethoxide. 9. The method according to claim 6, wherein the water-soluble organic solvent is N-methylpyrrolidone. 10. The method according to claim 6, wherein the alkylene oxide is propylene oxide or ethylene oxide. 11. A low-molecular-weight polyether polyol which is liquid at room temperature and an alkali metal alcoholate are reacted in a water-soluble organic solvent or in the absence of a solvent, and the low-molecular-weight alcohol produced is removed by distillation, followed by alkylene oxide. A method for producing a high-molecular-weight polyether polyol characterized by reacting. 12. The low molecular weight polyether polyol which is liquid at room temperature is a polyether polyol having a molecular weight of 500 or more obtained by the reaction of 1 mol of a polyhydroxy compound and 3 mol or more of an alkylene oxide which is solid at room temperature.
The manufacturing method described. 13. The alkali metal alcoholate is potassium t.
-The process according to claim 11, which is butoxide, potassium methoxide or potassium ethoxide. 14. The method according to claim 11, wherein the water-soluble organic solvent is N-methylpyrrolidone. 15. The method according to claim 11, wherein the alkylene oxide is propylene oxide or ethylene oxide.