JP2003113239A - Purified polyalkylene glycol and method for producing the same - Google Patents

Abstract

(57) [Problem] To provide a purified polyalkylene glycol from which low-molecular compounds in the polyalkylene glycol are efficiently removed, and to provide a method for producing such a purified polyalkylene glycol. SOLUTION: A crude polyalkylene glycol obtained by addition polymerization of a compound having two or more active hydrogens with an alkylene oxide is treated under reduced pressure with a thin-film molecular distillation machine to obtain water, ethylene glycol, diethylene glycol and lower aldehyde. To remove low molecular compounds such as

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a purified polyalkylene glycol and a method for producing the same, more specifically,
The present invention relates to a purified polyalkylene glycol from which low-boiling compounds, particularly water, ethylene glycol, diethylene glycol and lower aldehyde compounds have been removed, and a method for producing the same.

[0002]

2. Description of the Related Art Generally, polyalkylene glycol is produced by addition-polymerizing alkylene oxide such as ethylene oxide and propylene oxide with water and a compound having two or more active hydrogens such as ethylene glycol, diethylene glycol and propylene glycol. It At that time, in the step of producing the polyalkylene glycol, although the production amount varies depending on the production conditions, ethylene glycol, diethylene glycol, lower aldehydes and the like are simultaneously produced as a small amount of low molecular weight compounds. Regarding the removal of the relatively low boiling point compounds among these low molecular weight compounds, a method of already depressurizing the inside of the kettle after the alkylene oxide addition reaction and removing the compounds (Japanese Patent Laid-Open No. 11-116669)
Is proposed.

However, this method has not yet been able to remove relatively high-boiling compounds such as ethylene glycol and diethylene glycol from the above low-molecular compounds. In addition, commercially available products of these polyalkylene glycols usually contain the above-mentioned compounds because they are difficult to purify, the process cost is high, and the analysis of the low-molecular compounds is not easy. Has been sold and used. Therefore, in cosmetics, paints and the like, which are applications of these polyalkylene glycols, problems such as odor due to these by-products and adverse effects on emulsion stability and the like often occur.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a purified polyalkylene glycol in which low molecular weight compounds in polyalkylene glycol are efficiently removed. Another object of the present invention is to provide a method for producing such a purified polyalkylene glycol.

[0005]

In order to solve these problems, the present inventors have conducted diligent studies, and as a result, in order to efficiently obtain a purified polyalkylene glycol from which low molecular compounds in the polyalkylene glycol compound have been removed. I arrived. That is, as a result of various experiments, it was found that the low molecular weight compound can be efficiently removed by using the thin film type molecular distillation machine, and the present invention has been completed.

The purified polyalkylene glycol of the present invention is a polyalkylene glycol obtained by addition-polymerizing an alkylene oxide to a compound having two or more active hydrogens, and a low molecular weight compound having a molecular weight of 107 or less is not substantially detected. Characterize.

Since the purified polyalkylene glycol of the present invention is substantially free of low molecular weight compounds, it does not adversely affect odor and emulsion stability when used in cosmetics, paints and the like.

The method for producing a purified polyalkylene glycol of the present invention is a method for purifying a polyalkylene glycol obtained by addition-polymerizing an alkylene oxide to a compound having two or more active hydrogens. It is characterized in that a low molecular weight compound having a molecular weight of 107 or less is removed to obtain a purified polyalkylene glycol by treating with a thin film molecular distillation machine.

In the production method of the present invention, the thin-film molecular distillation machine is used for removing low-molecular compounds, so that it can be substantially detected by chemical analysis, instrumental analysis such as high performance liquid chromatography (HPLC), and the like. It becomes possible to remove low-molecular compounds to the extent that they cannot be performed.

The term "purification" used in the present invention is different from the known removal of the catalyst and the neutralized salt of the catalyst used in the production of polyalkylene glycol in the known purification of polyalkylene glycol. This means removing water, ethylene glycol, diethylene glycol, acetaldehyde, formaldehyde, etc. contained in polyalkylene glycol, which is not removed by the purification method.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the polyalkylene glycol is an organic compound having two or more hydroxyl groups and having a hydroxyl group at the terminal, which is obtained by adding an alkylene oxide to an organic compound having two or more active hydrogens. Says a compound. Here, the molecular weight of the polyalkylene glycol is 300 to
It is preferably in the range of 50,000. Molecular weight is 3
If it is less than 00, the polyalkylene glycol other than the low molecular weight compound to be removed may be partially removed, and if it is more than 50,000, the melt viscosity of the polyalkylene glycol is increased and the molecular distillation machine It becomes difficult to transfer and thin the film during processing. Active hydrogen 2 used in the preparation of polyalkylene glycol in the present invention
As the compound having at least one, generally, a compound having an alcoholic hydroxyl group, an amino group and a phenolic hydroxyl group can be mentioned. Specific examples thereof include ethylene glycol, propylene glycol, water, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, bisphenol A, butylamine, aniline glycerin, trimethylolpropane, tris (hydroxyethyl) isocyanurate, Pentaerythritol,
Examples thereof include compounds such as diglycerin, dipentaerythritol, sorbitol, monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, ethylenediamine and polyethyleneimine.

The alkylene oxide added to the compound having two or more active hydrogens is ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc. One of these alkylene oxides or a combination of two or more thereof is also available. It can be used in the present invention. In particular, a combination of ethylene oxide and other alkylene oxide is preferably used. When two or more polyalkylene glycols are used in combination, the present invention can be applied regardless of whether the addition form of alkylene oxide is block or random.

In the present invention, the low molecular weight compound removed from the crude polyalkylene glycol has a molecular weight of 107 or less, and examples thereof include compounds selected from water, ethylene glycol, diethylene glycol, acetaldehyde and formaldehyde. be able to.

Next, the thin film type molecular distillation machine used in the present invention will be explained. In general, thin-film molecular distillation machines include falling-film type ones in which liquid is made into a thin film and separated in a decompressed environment, and centrifugal force generated by rotation of a rotary disk while supplying liquid onto a high-speed rotary disk. There is a centrifugal type in which a thin film is formed and separated. Although any method can be used in the present invention, a centrifugal molecular distillation machine is preferable because a thin film thickness is easily obtained and the separation of low molecular weight compounds is good.

The method for producing a purified polyalkylene glycol using a centrifugal type molecular distillation machine comprises the steps of melting and liquefying the polyalkylene glycol, guiding the liquid polyalkylene glycol to the rotating disk, and conducting the guiding step. A temperature adjustment step of adjusting the polyalkylene glycol to a predetermined temperature, and a vaporization step of vaporizing the low-molecular compound by supplying a liquid polyalkylene glycol to the high-speed rotating disk under high vacuum to form a thin film. There is.

The treatment with the centrifugal molecular distillation machine according to the invention is performed by supplying the temperature of the crude polyalkylene glycol to the rotary disk, the rotation speed of the rotary disk, the degree of vacuum, the film thickness of the polyalkylene glycol on the rotary disk, etc. Affected by the conditions. Specifically, the supply temperature of the crude polyalkylene glycol to the rotary disk is preferably 100 to 250 ° C.
If this temperature is lower than 100 ° C, the low molecular weight compound cannot be effectively removed, and if it is higher than 250 ° C,
The purified polyalkylene glycol may be thermally deteriorated.

The rotating speed of the turntable is 500 to 20.
A range of 00 rpm is preferred. The rotating speed of the turntable is 50
When it is lower than 0 rpm, the polyalkylene glycol is not sufficiently thinned, and when it is higher than 2000 rpm, the low-molecular compound cannot be effectively removed, which is not preferable.

The degree of vacuum in the centrifugal molecular distillation machine is 1.
It is preferably in the range of 33 to 0.133 Pa. When the degree of vacuum is higher than 1.33 Pa, the low molecular weight compound cannot be sufficiently removed, and it is actually difficult to reduce the degree of vacuum to lower than 0.133 Pa.

Further, the film thickness on the rotating disk of the centrifugal type molecular distillation machine is preferably in the range of 10 to 100 μm at its end. If the film thickness is less than 10 μm, the treatment can be efficiently performed by the distiller, but it is necessary to increase the number of rotations of the turntable to obtain the film thickness, which is difficult. Further, if the film thickness is larger than 100 μm, the low molecular weight compound cannot be effectively removed, which is not preferable.

These conditions are not fixed and are not particularly limited to the above operating conditions as long as polyalkylene glycol can be obtained. Further, in the present invention, an azeotropic compound may be added in advance in order to efficiently remove the low molecular weight compound.

[0021]

The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 Crude polyethylene glycol 1000 (crude PEG100) was prepared by adding 21 mol of ethylene oxide to 1 mol of ethylene glycol by a known method.
0, molecular weight: 1000) was produced. This crude PEG1
For 000, the water content, ethylene glycol, diethylene glycol, and acetaldehyde were measured in advance by the following measuring method. Next, a centrifugal molecular distiller (MS-
180: manufactured by Nippon Vehicle Manufacturing Co., Ltd., the temperature of the supply liquid is 200 ° C., the degree of vacuum is 0.266 Pa, and the diameter of the rotating disk is 38 c
m, rotation speed of the turntable 1300 rpm, supply speed 20 kg
/ H and a film thickness of 18 μm at the end of the turntable was treated with crude polyethylene glycol 1000. About the obtained purified PEG1000 ethylene glycol,
Water content, ethylene glycol, diethylene glycol and acetaldehyde were measured by the same method as above. The measurement results are shown in Table 1.

Example 2 A crude polypropylene glycol polyethylene glycol block (with a molecular weight of 2000) was produced by adding 16 mol of propylene oxide to 1 mol of ethylene glycol by a known method and then adding 23 mol of ethylene oxide. Water, ethylene glycol and diethylene glycol, and acetaldehyde of this crude reaction product were measured in advance by the following method. Next, using the same centrifugal type molecular distillation machine as above, the temperature of the supply liquid is 200 ° C., the degree of vacuum is 0.133 Pa,
Rotating disk rotation speed 1000 rpm, supply speed 20 kg /
h, the treatment was performed under the condition that the film thickness at the end of the rotary disk was 25 μm. The water content, ethylene glycol, diethylene glycol and acetaldehyde of the obtained purified polypropylene glycol polyethylene glycol block were measured by the same method as described above. The measurement results are shown in Table 1.

(Method for measuring ethylene glycol and diethylene glycol) The ethylene glycol and diethylene glycol in the polyalkylene glycol were measured as follows. The elution time of ethylene glycol and diethylene glycol is measured in advance by preparative GPC. Next, ethylene glycol and diethylene glycol in the polyalkylene glycol are used for the above-mentioned preparative G
It was fractionated by PC and quantified by capillary GC. The analytical limit in this measuring method is 5 PPM or less.

(Determination of acetaldehyde) Acetaldehyde was determined by dissolving polyalkylene glycol in water and then reacting it with 2,4-dinitrophenylhydrazine to form a hydrazone compound. Extracted. Next, the methylene chloride extract was diluted with acetonitrile to a predetermined concentration, and this acetonitrile solution was measured by HPLC to quantify acetaldehyde.

(Measurement method of water content of polyalkylene glycol) The water content of the polyalkylene glycol was measured by dissolving the polyalkylene glycol in toluene having a known water content at a predetermined concentration and using a Karl Fischer water content meter. At that time, during the operation of molecular distillation and water content measurement, in order to avoid absorption of water in the atmosphere, in the molecular distillation, the effluent outlet was surrounded and the effluent was taken out while flowing dry air. The water content was measured in a glow box in a dry air atmosphere. The measurement limit is 5 PPM.

[0027]

[Table 1]

As is clear from the results in Table 1, ethylene glycol, diethylene glycol and acetaldehyde were all detected in the crude polyalkylene glycol, but in the polyalkylene glycol purified by molecular distillation, the above-mentioned three low molecular weight compounds were used. Is below the measurement limit. From this result, it can be seen that the treatment with the molecular distillation machine is very effective in removing these low molecular weight compounds.

[0029]

Since the purified polyalkylene glycol of the present invention does not contain a low molecular weight compound, it does not adversely affect odor, emulsion stability and the like when used in cosmetics, paints and the like.

Further, in the method for producing a purified polyalkylene glycol of the present invention, since the treatment is carried out by using a thin film molecular distillation machine, for example, chemical analysis, instrumental analysis such as high performance liquid chromatography (HPLC), etc. Low molecular weight compounds can be removed to the extent that they are substantially undetectable. Therefore, even if the obtained purified polyalkylene glycol is used in cosmetics, paints, etc., it does not adversely affect odor, emulsion stability and the like.

Claims (15)

[Claims] 1. A purified polyalkylene glycol characterized in that, in a polyalkylene glycol obtained by addition-polymerizing an alkylene oxide to a compound having two or more active hydrogens, a low molecular weight compound having a molecular weight of 107 or less is not substantially detected. . 2. The purified polyalkylene glycol according to claim 1, wherein the molecular weight of the polyalkylene glycol is in the range of 300 to 50,000. 3. The purified polyalkylene glycol according to claim 1 or 2, wherein the low molecular weight compound is removed by treating the polyalkylene glycol with a thin film molecular distillation machine. 4. The purified polyalkylene glycol according to claim 3, wherein the thin film molecular still is a centrifugal thin film molecular still. 5. The purified polyalkylene glycol according to any one of claims 1 to 4, wherein the polyalkylene glycol is polyethylene glycol. 6. The purified polyalkylene glycol according to claim 1, wherein the low molecular weight compound is a compound selected from water, ethylene glycol, diethylene glycol, acetaldehyde and formaldehyde. 7. A method for purifying polyalkylene glycol obtained by addition-polymerizing alkylene oxide to a compound having two or more active hydrogens, wherein crude polyalkylene glycol is treated with a thin film molecular distillation machine to obtain a molecular weight of 107. A method for producing a purified polyalkylene glycol, which comprises removing the following low molecular weight compound to obtain a purified polyalkylene glycol. 8. The method for producing a purified polyalkylene glycol according to claim 7, wherein the molecular weight of the polyalkylene glycol is in the range of 300 to 50,000. 9. The method for producing a purified polyalkylene glycol according to claim 7, wherein the thin film molecular distillation machine is a centrifugal thin film molecular distillation machine. 10. The method for producing a purified polyalkylene glycol according to claim 9, wherein the supply temperature of the crude polyalkylene glycol is 100 to 250 ° C. 11. The method for producing a purified polyalkylene glycol according to claim 9, wherein the rotating speed of the rotary disk of the thin film molecular distillation machine is 500 to 2000 rpm. 12. The vacuum degree of the thin film molecular distillation machine is 1.3.
It is 3-0.133 Pa, The manufacturing method of the refined polyalkylene glycol in any one of Claims 9 thru | or 11. 13. The film thickness of the polyalkylene glycol at the end of the rotary disk of the thin film molecular distillation machine is 10 to 10.
The method for producing a purified polyalkylene glycol according to any one of claims 9 to 12, wherein the range is 100 µm. 14. The method for producing a purified polyalkylene glycol according to claim 9, wherein the polyalkylene glycol is polyethylene glycol. 15. The production of the purified polyalkylene glycol according to claim 9, wherein the low molecular weight compound is a compound selected from water, ethylene glycol, diethylene glycol, acetaldehyde and formaldehyde. Method.