JP3263450B2 - Purification method of crude polyoxypropylene polyol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for purifying a crude polyoxypropylene polyol. More specifically, the present invention relates to a method for purifying a crude polyoxypropylene polyol produced by subjecting a compound having at least one active hydrogen to addition polymerization of propylene oxide. More specifically, the present invention particularly relates to a method for purifying a crude polyoxypropylene polyol containing an alkaline catalyst used as a polymerization catalyst.

[0002]

2. Description of the Related Art Hitherto, polyoxypropylene polyols have been obtained by addition polymerization of propylene oxide to an organic compound having at least one active hydrogen in the molecule in the presence of an alkaline catalyst. Examples of the alkaline catalyst used in this reaction include potassium hydroxide, sodium hydroxide, cesium hydroxide, sodium methylate, potassium methylate, metal potassium, metal sodium, potassium carbonate, and sodium carbonate. When these alkaline catalysts remain in the polyoxypropylene polyol, the applications of the polyoxypropylene polyol are polyurethane resins, cosmetic raw materials, surfactants,
Since it has a bad effect when used with a lubricant or the like, it must be removed.

A method for removing an alkaline catalyst or a neutralized salt thereof from a crude polyoxypropylene polyol containing an alkaline catalyst immediately after completion of a polymerization reaction is as follows.

For example, (A) Japanese Patent Publication No. 52-33000
(B) Activated clay, acid clay, synthetic silicic acid, by neutralizing the alkaline catalyst with an acid such as phosphoric acid, formic acid, hydrochloric acid, oxalic acid, halogenated oxyacid, or carbonic acid and removing the generated salt by filtration. A method using an alkaline adsorbent such as aluminum, synthetic magnesium silicate, etc.
A method of adding an organic solvent of No. -14359 and washing with water,
(D) A method of removing alkaline ions using an ion exchange resin, (E) A method of neutralizing an alkaline catalyst with phosphoric acid, filtering, and then deoxidizing with aluminum silicate, aluminum oxide, magnesium oxide, aluminum hydroxide, or the like. (F) a method of adding an organic solvent described in JP-B-45-40068 and removing the alkaline catalyst with aluminum silicate or the like; (G) simply adding water to the polymerization reactor after the completion of the polyoxypropylene polyol polymerization reaction and stirring. There is a washing method and the like. However, all of these methods have drawbacks, and improvements are desired.

[0005]

The conventional purification method (A)
In (A), (B) and (E), it takes a lot of time to filter the generated salts and adsorbent, and the productivity is reduced. ,
Since the filtration residue is a solid, there is a problem that the treatment of the solid is not easy. Further, since the solid content is impregnated with the polyoxypropylene polyol, reducing the yield of the polyoxypropylene polyol is also a problem. In the conventional purification methods (C) and (F), an organic solvent is used. Therefore, when this organic solvent is discarded, the cost of the organic solvent itself and a problem of wastewater treatment occur, and the organic solvent is redistilled. In the case of repeated use, problems arise in terms of equipment costs and energy costs. The conventional purification technique (D) also has a problem of regeneration of the used ion exchange resin and a problem of deterioration of the ion exchange resin.
Furthermore, the desired purification effect cannot be obtained even with the conventional purification technique (G), and if the purification becomes insufficient or a large amount of cleaning water is used to prevent this, the poly- In addition to the drawback that the amount of oxypropylene polyol increases and the yield decreases, there is also a problem that a large amount of time is required to separate water and polyoxypropylene polyol depending on the stirring conditions, thereby lowering productivity. .

The present invention has solved the above disadvantages and problems,
An object of the present invention is to provide a high-speed, high-efficiency, simple and low-cost purification method of polyoxypropylene polyol which does not use an organic solvent, an acid and an adsorbent.

[0007]

Means for Solving the Problems The present inventors have found that a high-efficiency emulsification process using a circulation type emulsifier (FIG. 1) can provide high washing efficiency and high-speed liquid separation. As a result of further study of various operating conditions, the present inventors have reached the present invention which enables continuous and effective purification of polyoxypropylene polyol. .

That is, the present invention provides a method for purifying a crude polyoxypropylene polyol, which comprises continuously contacting and emulsifying a crude polyoxypropylene polyol and water in the absence of an organic solvent in a circulation type emulsifier. It is.

The organic solvent in the present invention refers to aromatic, aliphatic, cycloaliphatic, heterocyclic organic solvents, ketones, halogenated hydrocarbons, low molecular alcohols and low molecular ethers.

[0010] The crude polyoxypropylene polyol is
Low molecular weight polyhydric alcohols such as methanol, ethanol, ethylene glycol, diethylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, and sucrose, and polyvalents such as monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, hexamethylenediamine, and aniline Amino compounds, phenol, cresol, bisphenol A,
Conventionally known active hydrogen compounds such as polyhydric phenols such as novolak, hydroxides of alkali metals such as lithium, sodium, potassium and cesium or hydroxides of alkali metals or magnesium and alkaline earth metals such as calcium Or conventional compounds such as compounds containing amino groups such as alkaline earth metals, triethylamine and triethylenetriamine, clathrate compounds consisting of alkali metals or alkaline earth metals and crown ethers, and interlayer transfer catalysts such as quaternary ammonium salts A polyoxypropylene polyol containing an alkaline catalyst and obtained by subjecting propylene oxide to ring-opening addition polymerization in the presence of a known alkaline catalyst. The alkaline catalyst is added in an amount at which the polyoxypropylene polyol can be polymerized to a molecular weight at which the polyoxypropylene polyol can be emulsified with water.

Water is a detergent for the alkaline catalyst in the crude polyoxypropylene polyol, and industrial water, ion-exchanged water and distilled water are used according to the purpose.

The circulating emulsifier preferably has the structure shown in FIG. 1, but if it has a structure capable of continuously emulsifying water and crude polyoxypropylene polyol, the structure shown in FIG. 1 is used. You don't have to have one. In FIG. 1, a crude polyoxypropylene polyol and water or a premixed crude polyoxypropylene polyol and water are charged from A into a circulation type emulsifier. The crude polyoxypropylene polyol and water are contact-emulsified by the stirring and emulsifying blade 1 of FIG. And repeated contact emulsification is performed.

This emulsion is separated into a polyoxypropylene polyol layer and an aqueous layer in a separation column, and then the polyoxypropylene polyol is heated and dried under reduced pressure to obtain a purified polyoxypropylene polyol.

The weight ratio of the crude polyoxypropylene polyol to water in the contact emulsification is usually from 1: 0.5 to 1: 2.5.
However, it is preferably 1: 0.6 to 1: 2.4, and more preferably 1: 0.7 to 1: 2.3. If the amount of water is less than this ratio, the washing of the alkaline catalyst in the crude polyoxypropylene polyol becomes insufficient,
If the ratio exceeds this ratio, the amount of the crude polyoxypropylene polyol dissolved in the aqueous layer increases, and the yield decreases or the liquid separation property deteriorates.

The temperature for carrying out the contact emulsification is 10 ° C. to 1 ° C.
00 ° C is preferred, more preferably 12 ° C to 95 ° C, most preferably 15 ° C to 90 ° C. When the contact emulsification is performed at a low temperature of less than 10 ° C., the solubility of the polyoxypropylene polyol in water increases, and the yield of the polyoxypropylene polyol decreases. When performed at a temperature higher than 100 ° C., it takes a long time (10 hours or more) to separate water and polyoxypropylene polyol, resulting in a significant decrease in productivity.

[0016]

EXAMPLES Examples of the present invention will be shown below to clarify aspects of the present invention. Example 1 A crude polyoxypropylene polyol (molecular weight 3000, potassium hydroxide content 0.15% by weight) obtained by subjecting propylene oxide to ring-opening addition polymerization of glycerin in the presence of potassium hydroxide and ion-exchanged water were as follows: 1 at a weight ratio of 1 to a circulation type emulsifier having a structure shown in FIG. 1 (discharge amount: 200 l / min, rotation speed of stirring emulsification blade: 1200 rpm).
Charged at ° C. The emulsion was sent to a separation tower, and after polyoxypropylene polyol and water, which had been emulsified and washed by contact emulsification, were separated into layers, the polyoxypropylene polyol was separated, and the potassium content after heating and drying under reduced pressure was measured. The time required to separate the polyoxypropylene polyol and water is within 10 hours. The potassium content of the purified polyoxypropylene polyol is 0.5 ppm or less, the yield of the polyoxypropylene polyol is 99%, and the purification of the polyoxypropylene polyol is carried out with extremely high efficiency. did it.

Comparative Example 1 Crude polyoxypropylene polyol (molecular weight: 3,000, potassium hydroxide content: 0.15% by weight) obtained by subjecting propylene oxide to ring-opening addition polymerization of glycerin in the presence of potassium hydroxide, and ion-exchanged water At a weight ratio of 1: 1 into a conventional reactor equipped with a squid-type stirrer, and washed with stirring at 20 ° C. (rotation speed of stirring blades: 120 rpm). Although there was no problem in the liquid separation properties of the emulsion, the potassium content in the purified polyoxypropylene polyol after heating and drying under reduced pressure was 340 ppm, and the removal of the alkali component in the polyoxypropylene polyol was insufficient.

Comparative Example 2 Crude polyoxypropylene polyol (molecular weight: 3000, potassium hydroxide content: 0.15% by weight) obtained by subjecting propylene oxide to ring-opening addition polymerization of glycerin in the presence of potassium hydroxide, and ion-exchanged water Was performed in a weight ratio of 1: 0.3, and the same operation as in Example 1 was performed, but the potassium content of the purified polyoxypropylene polyol was 240 ppm.
And the purification of the polyoxypropylene polyol was insufficient.

Comparative Example 3 Crude polyoxypropylene polyol (molecular weight 3000, potassium hydroxide content 0.15% by weight) obtained by ring-opening addition polymerization of propylene oxide with glycerin in the presence of potassium hydroxide, and ion-exchanged water Was used in a weight ratio of 1: 3.0, and the same operation as in Example 1 was performed. The potassium content of the purified polyoxypropylene polyol is 0.5 ppm, and there is no problem in the purification of the polyoxypropylene polyol. However, the yield of the purified polyoxypropylene polyol is 88%, which is not practical.

Comparative Example 4 A crude polyoxypropylene polyol (molecular weight 3000, potassium hydroxide content 0.15% by weight) obtained by ring-opening addition polymerization of propylene oxide with glycerin in the presence of potassium hydroxide, and ion-exchanged water At a weight ratio of 1: 1 to a circulation type emulsifier having a structure shown in FIG. 1 (discharge rate: 200 l / min, stirring emulsifier blade rotation speed: 1200 rpm) at 5 ° C.
Was charged. The emulsion was sent to a separation tower, and after polyoxypropylene polyol and water, which had been emulsified and washed by contact emulsification, were separated into layers, the polyoxypropylene polyol was separated, and the potassium content after heating and drying under reduced pressure was measured. The time required for separation of the polyoxypropylene polyol and water was within 10 hours, and the potassium content of the purified polyoxypropylene polyol was 0.5 ppm or less, but the problem that the yield was reduced to 90% occurred. .

Comparative Example 5 A crude polyoxypropylene polyol (molecular weight 3000, potassium hydroxide content 0.15% by weight) obtained by subjecting propylene oxide to ring-opening addition polymerization of glycerin in the presence of potassium hydroxide and ion-exchanged water At a weight ratio of 1: 1 to a circulating emulsifier having a structure shown in FIG. 1 (discharge amount: 200 l / min, rotation speed of stirring emulsifying blade: 1200 rpm).
Charged at 0 ° C. The emulsion was sent to a separatory column, and an attempt was made to separate the water from the polyoxypropylene polyol emulsified and washed by contact emulsification. The water was not separated even after 10 hours, and the polyoxypropylene polyol was not separated from the water. The polyol could not be purified.

[0022]

According to the present invention, polyoxypropylene polyol can be continuously purified with extremely high efficiency without using an organic solvent.

[0023]

[Brief description of the drawings]

FIG. 1 shows an example of a cross-sectional view of a circulation type emulsifier of the present invention.

[Explanation of symbols]

 1 stirring emulsifying wing

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Seiji Asai 2-1-1 Tango-dori, Minami-ku, Nagoya-shi, Aichi Examiner at Mitsui Toatsu Chemicals Co., Ltd. ▲ Yoshi ▼ Eiichi Sawa (56) Reference 1-294733 (JP, A) JP-A-60-255824 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 65/00-65/48 C08J 3/00 B01D 11 / 00-12/00

Claims (3)

(57) [Claims] 1. A method for purifying a crude polyoxypropylene polyol, comprising continuously contacting and emulsifying a crude polyoxypropylene polyol and water in a circulation type emulsifier in the absence of an organic solvent. 2. The method for purifying a crude polyoxypropylene polyol according to claim 1, wherein the weight ratio of the crude polyoxypropylene polyol to water is 1: 0.5 to 1: 2.5. 3. The method for purifying a crude polyoxypropylene polyol according to claim 1, wherein the crude polyoxypropylene polyol and water are contact-emulsified at 10 ° C. to 100 ° C.