JPS6220970B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for purifying polyether polyols. Conventionally, polyether polyols (hereinafter referred to as polyethers) are obtained by addition polymerizing an alkylene oxide to an organic compound having at least one active hydrogen group in the molecule in the presence of an alkaline catalyst. In addition, examples of alkaline catalysts used in this reaction include caustic potash,
Examples include caustic soda, sodium methylate, potassium methylate, metallic potassium, potassium carbonate, and sodium carbonate. If these alkaline catalysts or their neutralized salts remain in polyether, they may be used in all uses of polyether, such as raw materials for polyurethane resins, raw materials for brake fluids, raw materials for cosmetics, raw materials for activators, raw materials for synthetic lubricating oils, etc. Since it has a negative effect on the environment, it is usually removed. Conventional purification methods for removing alkaline catalysts or their neutralized salts from polyethers containing alkaline catalysts include the following. (a) A method of neutralizing an alkaline catalyst with an acid and removing the resulting salt by filtration, as disclosed in Japanese Patent Publication No. 37-5597, Japanese Patent Publication No. 41-21237, and Japanese Patent Publication No. 47-3745. (b) Special Publication No. 38-26158, Special Publication No. 13021, Special Publication No. 42-13021, Special Publication No. 32432, Special Publication No. 45-33194, Special Publication No.
52-10018 and Japanese Patent Publication No. 53-123499, etc., methods using an alkali adsorbent with or without neutralization. (c) Method of dissolving in a solvent and washing with water, as disclosed in Japanese Patent Publication No. 14359/1983. (d) A method using the ion exchange resin disclosed in Japanese Patent Publication No. 36-22148 and Japanese Patent Application Laid-Open No. 51-23211. (e) A method disclosed in Japanese Patent Publication No. 52-33000 in which an alkaline catalyst is neutralized with carbon dioxide gas and the resulting carbonate is filtered. (f) A method of neutralizing with phosphoric acid and filtration as described in JP-A-51-101098, and then deoxidizing the filtrate with magnesium silicate, aluminum oxide, magnesium oxide, aluminum hydroxide, aluminum carbonate, or a mixture thereof. All of these purification methods have major drawbacks, and improvements are desired. In other words, in (a), the salt particles produced are fine and unstable, making filtration extremely difficult, and being sensitive to fluctuations in filtration pressure, which tends to cause large variations in quality and cloudiness. . In addition, halogen-based acids extremely corrode stainless steel, which places extreme restrictions on the material of the equipment, and also causes heavy metal ions to be eluted from the equipment, interfering with the use of polyether. Although (b) is a relatively preferable method in terms of performance,
Since these adsorbents do not have sufficient alkali adsorption ability, they must be used in powder form in large quantities, and it takes a very long time to complete adsorption. Furthermore, the quality of the filtrate deteriorates as the filtration time passes and the filtration pressure increases. In (c), even if electrostatic coalescence is used to promote the purification effect, the purification effect is insufficient, and problems arise with the residual amount of potassium + sodium, odor, hue, pH value, etc. In (d), the ion exchange rate is very slow, organic impurities contained in the ion exchange resin are eluted into the polyether, deteriorating the hue, odor, etc., and the amount of potassium + sodium remaining is large. In (e), the particle strength of the alkali metal carbonate produced by carbon dioxide gas neutralization is weak, so it is destroyed by the filtration pressure and easily passes through the filter membrane, resulting in the potassium + sodium content of the polyether. The amount increases and sometimes a slight turbidity occurs. Furthermore, the polyether obtained by this method tends to have a high acid value, which is particularly problematic as a raw material for polyurethane resin. (F) is the same as method (B) up to phosphoric acid neutralization and filtration, and is a well-known fact.The feature of the invention is rather that it lowers the residual acid value, and the concept of the purification method and Judging from the effectiveness, this method is no better than method (a). The present inventors have conducted extensive research to improve the above-mentioned drawbacks, and as a result, have arrived at the present invention. That is, a polyether containing an alkaline catalyst synthesized in the presence of an alkaline catalyst is neutralized with (a) acid salts containing sodium or lithium in the presence or absence of water, and then dehydrated if necessary. A polyether purification method characterized by filtration of polyether and polyether containing an alkaline catalyst synthesized in the presence of an alkaline catalyst in the presence or absence of water (a) acidic salts containing sodium or lithium. After neutralization, (b) add adsorbent, dehydrate if necessary,
This method of purifying polyether is characterized in that it is then filtered. The polyether to which the present invention can be applied is one obtained by addition polymerizing an alkylene oxide to an organic compound having at least one active hydrogen group in the molecule in the presence of an alkaline catalyst. Examples of organic compounds having at least one active hydrogen group in the molecule used as raw materials for polyether include monohydric alcohols such as methanol, ethanol, butanol, octanol, and lauryl alcohol, ethylene glycol, propylene glycol, and 1.4. Dihydric alcohols such as butanediol,
These include polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, sorbitol, and sucrose, and amine compounds such as aniline, ammonia, ethylenediamine, diethylenetriamine, and toluenediamine. Further, the alkylene oxide includes, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, and the like. The polyether obtained by addition polymerization in this manner is usually a viscous liquid containing 0.1 to 1% by weight of an alkaline catalyst. Next, the purification method of the present invention will be described. The purification method of the present invention consists in first neutralizing the polyether containing an alkaline catalyst with an acid salt containing an excess equivalent of sodium or lithium in the presence or absence of water. When neutralization is carried out in the presence of water, up to 5% by weight, preferably from 0.5 to 2% by weight of water is added to the polyether containing the alkaline catalyst. Neutralization is carried out at a temperature of 30-100°C. The acidic salt used in the present invention is, for example,
_NaHSO3 , _NaHSO4 , _NaH2PO4 , _{NaHPO2 ,
NaHCO3} , _LiHSO3 , _LiHSO4 , _{LiH2PO4 ,}
These include LiHPO ₂ , LiHCO ₃ and their aqueous solutions. If the neutralized product shows near neutrality after neutralization,
After removal of water from the neutralized product, that is, dehydration, if necessary, is performed and then filtered. If dehydration is not necessary, it can be directly filtered. When dehydrating, the temperature should be 80℃ or higher, preferably 100℃ or higher.
Conducted at 140°C and under reduced pressure. If the neutralized product is acidic or alkaline, an adsorbent is added for treatment. If the neutralized product is acidic, an acid adsorbent is added, and if the neutralized product is alkaline, an alkali adsorbent is added. Examples of acid adsorbents include synthetic magnesium silicate, synthetic aluminum silicate, Li ₂ CO ₃ , Na ₂ CO ₃ , MgCO ₃ ,
Group and group carbonates such as CaCO ₃ , MgO,
CaO, Mg(OH) ₂ , Ca(OH) ₂ , _Al2O3 , _Al
(OH) Oxides or hydroxides of groups such as ₃ , 2.5MgO・Al ₂ O ₃・XH ₂ O, Mg ₆ Al ₂
(OH) ₁₆ Complex salts of group compounds such as CO ₃ and 4H ₂ O, or mixtures thereof. Examples of the alkali adsorbent include synthetic magnesium silicate, synthetic aluminum silicate, activated clay, and acid clay. The preferred amount of the adsorbent used in the present invention is 2% by weight or less based on the polyether,
Preferably it is 0.05 to 0.5% by weight. Next, after treating the neutralized product with an adsorbent, if dehydration is necessary, dehydration is performed under the above conditions, and then filtered. If dehydration is not necessary, it can be directly filtered. The purified polyether obtained according to the purification method of the present invention fully satisfies the specifications required for all applications, such as the following specifications required for one-shot polyurethane foam applications. Appearance Transparent liquid, *no turbidity or mist**Color (APHA=U.S. Public Health Act) 20 or less Moisture 0.05% or less*※*Potassium + Sodium 5ppm or less*※※※PH 6.5-7.5 Odor Note: Almost none Note: Turbidity, presence or absence of suspended matter or suspended particles in the misty polyether. ※※Hue Based on Hazen No. method. ※※※ Potassium + Sodium Based on atomic absorption method. ※※※※PH Dissolve 10g of sample in 100c.c. of isopropanol:water (10:6 volume ratio) solution and measure. Among the above items, regarding potassium + sodium
Must be 1.0ppm or less. If the polyether does not meet these standards, one-shot polyurethane foam may cause cracking, shrinkage, or discoloration of the foam, and polyurethane prepolymers may cause abnormal solidification or pot life abnormalities. Examples are shown below. In the examples, "%" and "part" are based on weight. Example 1 7.5 g of caustic potash (85%) was added to 92 g of glycerin, then 2500 g of propylene oxide was introduced at a reaction temperature of 130°C and a reaction pressure of 10 Kg/cm ² G, and then 500 g of ethylene oxide was added at a reaction temperature of 120°C and a reaction pressure of 3 Kg. /cm ² G to produce polyether. Next, add 30g of water and mix evenly, then add 90g of water.
Sodium bisulfite aqueous solution (30% by weight) at °C
40g was added to neutralize. The pH after neutralization was 5.8. Next, synthetic magnesium silicate was used as an acid adsorbent.
1.5g was added and treated at 90°C for 2 hours. then 120
After distilling off water at a temperature of 10 mmHg or lower, the mixture was filtered through a glass filter using diatomaceous earth as a filter aid. The filtrate showed the following analytical values and was found to have good quality as a polyether for polyurethane resin. Analysis item Analysis value Acid value (mgKOH/g) 0.007 Moisture (%) 0.016 Sodium (ppm) 0.05 Potassium (ppm) 0.10 PH 7.0 Hydroxyl value (mgKOH/g) 56.8 Appearance Colorless transparent liquid Example 2 The following three types The polyether was synthesized in the presence of an alkali catalyst. Polyether A: 4.8 kg of glycerin and 850 g of caustic potash (85%) were placed in a 200 stainless steel autoclave.
Propylene oxide 145.2 after nitrogen substitution
Kg was introduced at 125℃ and 6Kg/cm ² G, and once the reaction was completed, 30Kg of ethylene oxide was introduced.
The reaction was carried out at 115° C. and at a rate of 2 Kg/cm ² G. Polyether B: 50Kg of 70% sucrose syrup, 5Kg of ethylene glycol, 10Kg of ethylenediamine and caustic soda (48%) in 200 autoclaves
After charging 375g, heat to 105℃ after purging with nitrogen, introduce 50Kg of propylene oxide at 2Kg/cm ² G, complete the reaction, distill off water at 125℃, and then add 65Kg of propylene oxide.
was introduced at 125° C. and 2 Kg/cm ² G to complete the reaction. Polyether C: 6 kg of 70% sorbitol, 6 kg of dipropylene glycol, and 800 g of caustic potash (48%) were placed in a 200° autoclave, and after distilling water off at 125°C and below 10 mmHg, propylene oxide was added.
180 Kg was introduced at 125° C. and 5 Kg/cm ² G, and then 6 Kg of ethylene oxide was introduced at 115° C. and 2 Kg/cm ² G to complete the reaction. When these various polyethers obtained were purified according to the method of the present invention, the results were as shown in Table 1. Incidentally, the filtration was carried out using an ultra filter (manufactured by Miura Chemical Industry Co., Ltd.).

[Table] Example 3 Under the conditions of Example-2, sampling was performed over time during filtration to examine fluctuations in the analytical values of potassium and sodium in the polyether that had passed through the filter membrane. As shown in Table 2, all the samples from the initial filtration to the squeezed sample showed good analytical values, demonstrating the features of the present invention.

[Table] Comparative Example 1 A polyether was synthesized in exactly the same manner as in Example-1. This polyether was neutralized by adding 37.1 g of a 30% phosphoric acid aqueous solution at 90°C. The pH of the neutralized polyether was 5.6. Next, 15 g of acid adsorbent 2.5MgO.Al ₂ O ₃ .XH ₂ O was added and treated at 90° C. for 2 hours. Next, after distilling off the water at 120℃ and below 10mmHg,
It was filtered through a glass filter using diatomaceous earth as a filter aid. The filtrate had white fine particles suspended in it and had a strong aldehyde odor. Analysis item Analysis value Moisture (%) 0.014 Acid value (mgKOH/g) 0.21 PH 6.0 Sodium (ppm) 0.10 Potassium (ppm) 142 Hydroxyl value (mgKOH/g) 57.1 Appearance White suspension liquid comparative example 2 Example - A polyether was synthesized using exactly the same procedure as in Example 1. An attempt was made to purify this polyether using the following procedure. (1) Neutralize polyether by adding 37.1g of 30% phosphoric acid aqueous solution at 90℃, then neutralize it at 120℃ for 10
After water was distilled off at a temperature below mmHg, the mixture was filtered using diatomaceous earth as a filter aid. The analytical values of the purified polyether were as shown in Table 3. (2) 31g of synthetic magnesium silicate in polyether
and 60 g of water were added thereto, followed by stirring at 120° C. for 1 hour, dehydration, and filtration using diatomaceous earth as a filter aid. The analytical values of the purified polyether were as shown in Table 3. (3) 2000g of normal hexane was added to polyether and dissolved. Next, 2000 g of water was added, mixed and allowed to stand, but the mixture remained in an emulsified state and no signs of separation were visible even after 24 hours. (4) After adding 6 g of water to the polyether and stirring it uniformly, the mixture was neutralized by blowing in 8.5 g of carbon dioxide gas at 55°C. The pH became 6.7 and the mixture became cloudy. Next, nitrogen gas was bubbled at 80 ml/min for 30 minutes while maintaining the same temperature. Take this out and under reduced pressure
After dehydration at 110°C for 30 minutes, the mixture was filtered using diatomaceous earth as a filter aid. The analytical values of the purified polyether were as shown in Table 3. (5) Add 150g of water to polyether and add H
Space velocity is lowered through a heat insulating tube with an inner diameter of 35 mm (kept at 80°C) filled with 300 ml of cation exchange resin (Daiseion SKIB, Mitsubishi Kasei Corporation) recycled into a mold.
12.5 and then dehydrated on a rotary evaporator at 120°C and below 10 mmHg. The obtained purified polyether showed the analytical values shown in Table 3.

[Table] All of the polyethers for polyurethane resin were of poor quality, but method (4) was relatively good. Comparative Example 3 Polyether A, polyether B, and polyether C were synthesized in the same manner as in Example-2. For these polyethers, a scale-up test was conducted using method (4), which had relatively good results in Comparative Example-2. That is, in a 200 stainless steel autoclave, 2% water was added to polyether, mixed uniformly, and then neutralized by blowing in a predetermined amount of carbon dioxide gas at 60°C, and then mixed with nitrogen gas while stirring. Bubbled for 30 minutes. Then 110℃
After dehydration by topping for 30 minutes, the mixture was filtered through an Ultra Filter (manufactured by Miura Chemical Industry Co., Ltd.) using diatomaceous earth as a filter aid. When samples were taken at regular intervals from the start of filtration, the results were as shown in Table 4, and it was found that there was extremely large variation in quality.

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Claims (1)

[Claims] 1. A polyether polyol containing an alkaline catalyst synthesized in the presence of an alkaline catalyst is neutralized with (a) acidic salts containing sodium or lithium in the presence or absence of water, and then A method for purifying polyether polyol, which comprises dehydration if necessary and then filtration. 2. Polyether polyol containing an alkaline catalyst synthesized in the presence of an alkaline catalyst is neutralized with (a) acid salts containing sodium or lithium in the presence or absence of water, and then (b) adsorbent is added. A method for purifying a polyether polyol, which comprises adding, dehydrating if necessary, and then filtering. 3. The method for purifying polyether polyol according to claim 2, wherein the adsorbent is an acid adsorbent or an alkali adsorbent.