JP2007332036A - Method for purifying glyceryl ether - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for purification by which a sufficiently deodorized glyceryl ether can efficiently be obtained. <P>SOLUTION: The method for purifying the glyceryl ether is a method for purification comprising using a distillation column having a structure in which the central part of the column is divided into two distillation parts. The method for purification is carried out as follows. The crude glyceryl ether containing the specific glyceryl ether and a lower-boiling component and a high-boiling component having a different boiling point from that of the glyceryl ether as impurities is fed to one of the divided distillation parts in the central part of the column and separated into a fraction (a) containing the low-boiling component, a fraction (b) containing the high-boiling component and the purified glyceryl ether. Furthermore, the purified glyceryl ether is separated from the other divided distillation part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a purification method of glyceryl ether, and more particularly to a purification method capable of efficiently obtaining a sufficiently deodorized purified glyceryl ether from crude glyceryl ether.

Glyceryl ether is a useful compound in the fields of cosmetics, cosmetics, chemicals, agricultural chemicals, pharmaceuticals and the like. Glyceryl ether has particularly excellent performance as a nonionic surfactant having W / O type emulsification characteristics, and has been widely applied to cosmetic base materials as emulsifiers, solubilizers, lubricants and the like. Yes.
Glyceryl ether can be obtained by hydrolyzing glycidyl ether and opening the ring, and various proposals have been made as hydrolysis methods thereof. For example, a method in which glycidyl ether is reacted with a carboxylic acid to produce a glycerol monoester and then hydrolyzed under an acid catalyst (Patent Document 1), a glycidyl ether and a carbonyl compound are reacted, and a 1,3-dioxolane compound And then hydrolyzing in the presence of an acid catalyst (Patent Document 2), hydrolyzing in the presence of carboxylic acid and alkali (Patent Document 3), and non-catalytic hydrolysis in a subcritical state (Patent Document 4) and the like are known.

On the other hand, surfactants used in the fields of cosmetics, cosmetics and the like are desired to reduce the content of odorous components as much as possible from the viewpoint of emphasizing fragrance during product preparation. Therefore, a method of deodorizing the crude glyceryl ether by bringing it into contact with water vapor, nitrogen, or an inert gas is known (Patent Document 5). However, since glyceryl ether has a high boiling point, when the odor component is not low boiling point, there are many cases where sufficient purification cannot be performed due to problems of thermal stability and chemical stability of glyceryl ether. Further, during the distillation operation, thermal decomposition of high boiling impurities in the crude glyceryl ether may occur, and a new odor component may be generated.
Moreover, although the distillation method (patent document 6) using the distillation column which has a structure where the column intermediate part was divided into two distillation parts is proposed, the concrete purification method of the compound is not disclosed.

Japanese Patent Publication No. 1-55263 Japanese Examined Patent Publication No. 61-26997 JP 2002-114727 A JP 2002-88000 A JP-A-6-80600 JP 2004-230251 A

  An object of the present invention is to provide a purification method capable of efficiently obtaining a sufficiently deodorized glyceryl ether.

When purifying glyceryl ether containing a thermally decomposable high-boiling component, the present inventors used a distillation column having a structure in which the central portion of the column is divided into two distillation portions, and used a low-boiling component, a high-boiling component, and It has been found that the above-mentioned problems can be solved by simultaneously separating purified glyceryl ether.
That is, the present invention is a purification method using a distillation column having a structure in which the central part of the column is divided into two distillation units, and includes glyceryl ether represented by the following general formula (1) and the glyceryl ether as an impurity. The crude glyceryl ether containing a low-boiling component and a high-boiling component having different boiling points is supplied to one of the separated distillation sections in the center of the column, and the fraction (a) containing the low-boiling component is mixed with the high-boiling component. There is provided a method for purifying glyceryl ether, which is separated into a fraction (b) containing, and purified glyceryl ether, and the purified glyceryl ether is extracted from the other distillation section.

(In the formula, R represents a substituted or unsubstituted saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, OA represents an oxyalkanediyl group having 2 to 4 carbon atoms, and p represents an average added mole number. The number is 0 to 20, and when p is 2 or more, OA may be the same or different.)

  According to the method of the present invention, since a low-boiling odor component generated by thermal decomposition of a high-boiling component does not enter into a refined product, a sufficiently deodorized glyceryl ether can be easily obtained.

(Glyceryl ether)
The subject of purification in the method of the present invention is a crude glyceryl ether containing as a main component a glyceryl ether represented by the following general formula (1) (hereinafter sometimes simply referred to as “glyceryl ether”). Glyceryl ether can be obtained by hydrolyzing glycidyl ether represented by the following general formula (2) (hereinafter sometimes simply referred to as “glycidyl ether”).

(In the formula, R represents a substituted or unsubstituted saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, OA represents an oxyalkanediyl group having 2 to 4 carbon atoms, and p represents an average added mole number. The number is 0 to 20, and when p is 2 or more, OA may be the same or different.)

（式中、Ｒ、ＯＡ、及びｐは、前記と同じである。）

(In the formula, R, OA, and p are the same as described above.)

  In the general formula (1), examples of the hydrocarbon group having 1 to 20 carbon atoms represented by R include a substituted or unsubstituted saturated or unsaturated hydrocarbon group. For example, a C1-C20 linear or branched alkyl group, a C2-C20 linear or branched alkenyl group, a C6-C14 aryl group, etc. are mentioned. In such hydrocarbon groups, some or all of the hydrogen atoms may be substituted with fluorine atoms. The substitution degree and substitution position in the case of substitution with a fluorine atom are not particularly limited.

Specific examples of R include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n- Decyl group, n-dodecyl group, isodecyl group, n-tetradecyl group, n-hexadecyl group, n-octadecyl group, n-eicosyl group, 2-propyl group, 2-butyl group, 2-methyl-2-propyl group, Examples include 2-pentyl group, 3-pentyl group, 2-hexyl group, 3-hexyl group, 2-octyl group, 2-methyloctyl group, 2-ethylhexyl group, isooctadecyl group, phenyl group, benzyl group and the like.
Specific examples of the hydrocarbon group in which the hydrogen atom of R is substituted with a fluorine atom include a nanofluorohexyl group, a hexafluorohexyl group, a tridecafluorooctyl group, a heptadecafluorooctyl group, a heptadecafluorodecyl group, etc. Perfluoroalkyl group and the like.
Specific examples of the oxyalkanediyl group having 2 to 4 carbon atoms represented by OA include an oxyethylene group, an oxytrimethylene group, an oxypropane-1,2-diyl group, and an oxytetramethylene group.

Specific examples of glycidyl ether that is a raw material of glyceryl ether include n-butyl glycidyl ether, 2-methyl-propyl glycidyl ether, n-pentyl glycidyl ether, 2-methyl-butyl glycidyl ether, 2-methyl-pentyl glycidyl ether, Examples include n-hexyl glycidyl ether, 2-ethyl-hexyl glycidyl ether, n-octyl glycidyl ether, 2-methyloctyl glycidyl ether, isodecyl glycidyl ether, isooctadecyl glycidyl ether, n-stearyl glycidyl ether, and phenyl glycidyl ether. .
Specific examples of glyceryl ether include glyceryl ether obtained by hydrolyzing glycidyl ether shown in the above specific examples.
Among the glyceryl ethers represented by the general formula (1), R is preferably a hydrocarbon group having 1 to 12 carbon atoms, and OA is an oxyethylene group, an oxy group from the viewpoint of improving reactivity and reaction selectivity. One or more groups selected from a trimethylene group, an oxypropane-1,2-diyl group, and an oxytetramethylene group are preferred, and p is preferably 0 to 5, and more preferably 0.

(Hydrolysis of glycidyl ether)
The hydrolysis method of glycidyl ether is not specifically limited, A well-known method is employable. For example, (i) a method in which an epihalohydrin is added to an alcohol to obtain an alkyl glycidyl ether, and this is hydrolyzed with an acid catalyst-containing aqueous solution to obtain an alkyl glyceryl ether. (Ii) a glycidyl ether is reacted with a carboxylic acid. A method in which glycerol monoester is produced and then hydrolyzed in the presence of an acid catalyst (see Japanese Patent Publication No. 1-55263), (iii) a method in which glycidyl ether is hydrolyzed in the presence of a carboxylic acid and an alkali (Japanese Patent Laid-Open No. 2002-2002) 114727), (iv) a non-catalytic hydrolysis method under subcritical conditions (see JP-A No. 2002-88000), and the like.

Among the above hydrolysis methods, high yield and no need for treatment of catalyst-containing wastewater (iv) Non-catalytic hydrolysis under subcritical conditions (hereinafter referred to as “subcritical method”) Is particularly preferred. In the subcritical method, in the presence of water in a subcritical state (subcritical water), specifically, water at a temperature exceeding a saturated vapor pressure at a temperature of 250 to 350 ° C. (4 to 16.5 MPa). Hydrolysis of glycidyl ether is carried out in the presence without catalyst. The temperature is more preferably 270 to 330 ° C., and the pressure is more preferably 6 to 13 MPa.
Since the dielectric constant of subcritical water is greatly reduced, glycidyl ether, which is insoluble in water at room temperature, is easily dissolved in subcritical water and the reaction system becomes uniform, so that the reactivity is high. The reaction proceeds even without catalyst and glyceryl ether can be obtained in high yield. In addition, in a highly stable glycidyl ether system that hardly occurs until the main chain such as a hydrocarbon chain is decomposed during hydrolysis, hydrolysis is performed in a supercritical state (374 ° C. or higher, 22 MPa or higher) exceeding the subcritical state. You can also.

The charging ratio of subcritical water and glycidyl ether (subcritical water / glycidyl ether) is preferably 20 to 500 mol times, and more preferably 40 to 200 mol times.
Hydrolysis under subcritical conditions proceeds without a catalyst, but an alkali can be added in order to avoid the influence of a small amount of chloride that may be mixed in the raw material glycidyl ether. The alkali used is preferably an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. The amount of alkali added is preferably a molar amount corresponding to the chlorine content of the chloride.
In the subcritical method, a solvent is not necessarily required, but a solvent can be used according to the properties of the raw material glycidyl ether and the solubility in subcritical water. In this case, it is preferable to use a solvent having low reactivity under subcritical conditions. The reaction form may be batch or continuous.

  The purification method of the present invention is a purification method using a distillation column having a structure in which the central part of the column is divided into two distillation parts, and the glyceryl ether represented by the following general formula (1) and the glyceryl as impurities. A crude glyceryl ether containing a low-boiling component and a high-boiling component having a boiling point different from that of ether (hereinafter, simply referred to as “crude glyceryl ether”) is supplied to one of the separated distillation sections in the center of the column to produce a low-boiling component. The glyceryl ether is separated from the fraction (a) containing high-boiling components, the fraction (b) containing high-boiling components, and the purified glyceryl ether, and the purified glyceryl ether is extracted from the other distillation section.

As the crude glyceryl ether, those obtained by hydrolyzing glycidyl ether by the above-mentioned subcritical method are preferable. This crude glyceryl ether contains glyceryl ether as a main component in an amount of 80% by mass or more, preferably 95% by mass or more. In addition, unreacted glycidyl ether, a low-boiling component, a thermally decomposable high-boiling component, etc. It contains less than 20% by mass, preferably less than 5% by mass.
Here, the low boiling point component means a low boiling point product having a higher vapor pressure than glyceryl ether, specifically, alcohols such as ethanol, isopropyl alcohol, butanol, 2-ethylhexanol, acetaldehyde, propanal, Examples include aldehydes such as butanal, glycidyl ether, and the like. The high boiling point component means a high boiling point substance having a vapor pressure lower than that of glyceryl ether, and specifically includes 1,3-dialkyl glyceryl ether, dimer of glyceryl ether, reverse adduct, and the like. It is done.

(Distillation tower)
In the present invention, a distillation column having a structure in which the central portion of the column is divided into two distillation units (hereinafter sometimes referred to as “dividing column”) is used. The distillation section in the distillation column can be divided by installing a partition plate or a cylindrical tube in the central portion (middle stage) of the distillation column.
FIG. 1 is a diagram showing an example of a distillation column in which a central portion of the column is divided using an internal partition plate. The central portion of the distillation column (dividing column) 1 is divided into two distillation portions (A, A ′) and (B, B ′) by an internal partition plate 2. The upper part (C) and the lower part (D) of the distillation column 1 are the same as the structure of a normal distillation column.
Further, the number and position of the fraction outlet are not particularly limited.
The dividing column is not particularly limited as long as multi-component separation is possible, but a distillation column such as “column in column” (Sumiju Plant Engineering Co., Ltd., registered trademark) is preferably used.

For the distillation section (gas-liquid contact section; A, A ′, B, B ′, C, and D) in the distillation column 1, any of a shelf and a packed bed can be used.
Examples of trays used for the shelves include valve trays, bubble bell trays, perforated plate trays, lift trays, flexi trays, and nutter float valve trays.
The packing used in the packed bed includes ring-type packings such as Raschig rings and pole rings, saddle (horse-shoe-shaped) packings such as bell saddles and interlock saddles, as well as McMahon packing, Canon packing and Dixon packing. , Terralet, Spray Pack, Pana Pack, Interpack, Good Low Packing, Stedman Packing, SFLOW (manufactured by Sumiju Plant Engineering Co., Ltd.), and the like. Among these, it is preferable to use a regular packing such as SFLOW (manufactured by Sumiju Plant Engineering Co., Ltd.) having a small pressure loss from the viewpoint of reducing the thermal load on the product because the number of distillation stages per packed column height is large. .

The distillation raw material (crude glyceryl ether) is supplied from the raw material supply port 3 to the central part (middle part) of the distillation column 1. In the distillation section (A, A ′) on the raw material supply side, there may be a shelf or a packed bed on both the upper and lower sides of the raw material supply port 3, and there may be a shelf or a packed bed on only one of the upper and lower sides. Good.
A distillation outlet 4 for a fraction (a) containing a low-boiling component is provided at the top of the distillation column 1, a purified product outlet 5 is provided at the middle stage of the tower, and a high-boiling component is contained at the bottom of the tower. An outlet 6 for the fraction (b) is provided. The refined product outlet 5 in the middle stage of the column is connected to the other distillation section (B, B ′) adjacent to one distillation section (distillation section on the raw material supply side; A, A ′) divided by the internal partition plate 2. Provided.
The fraction (a) containing the low-boiling components from the distillation outlet 4 at the top of the tower is discharged out of the tower as vapor, cooled by the condenser 7, and then partly taken out as a distillate and partly refluxed. It may be returned to the top, or all the condensate may be refluxed with an internal condenser (not shown) provided at the top of the column, and a part thereof may be taken out as a distillate.

A part of the fraction (b) containing the high-boiling components from the distillation outlet 6 at the bottom of the tower is heated by the heater 8 and circulated to the bottom of the tower, and a part thereof is taken out as a distillate.
The type of the heater 8 is not particularly limited, and a natural circulation type (thermo siphon type), an external circulation type, an insertion type, an overflow tube bundle type (kettle type), or the like can be used. Especially, it is preferable to use an external circulation type from a viewpoint of the deterioration prevention by the heat history of the fraction (b) containing a high boiling point component. As the heat medium, hot oil, high-pressure steam, or the like can be used.
In the present invention, the distillation method is not particularly limited as long as the distillation operation is performed using a dividing column, and a known method can be employed. The distillation operation may be either batch or continuous, and continuous distillation with a short heating residence time is more preferable. Examples of the distillation format include rectification, molecular distillation, steam distillation, and azeotropic distillation. These can be performed alone or in combination of two or more.

(Distillation purification using a dividing tower)
In distillation using a dividing column, by supplying crude glyceryl ether, a fraction (a) containing a low-boiling component is extracted from the top of the column, and a fraction (b) containing a high-boiling component is extracted from the bottom of the column, Fractions containing purified glyceryl ether are withdrawn simultaneously from the middle stage of the column.
In crude glyceryl ether, there are substances that generate odors when heat load is applied, and glyceryl ether itself is accompanied by generation of odor substances due to heat load, so the distillation operation is glyceryl ether and other pyrolytic properties. In order to suppress thermal decomposition of the substance, it is preferable that the heat load be as low as possible.
Therefore, the column bottom liquid temperature in the dividing column is preferably 100 to 300 ° C., more preferably 120 to 200 ° C., and the column bottom pressure in the dividing column is preferably 0.1 to 20 kPa, more preferably 0.1. Distillation is performed at ˜5 kPa. In addition, it is preferable to make low the liquid temperature in a division tower in the range which does not prevent the separation of a high boiling point component. Further, a method of blowing high-pressure steam or inert gas from the bottom of the dividing tower or a method of flash evaporation can be employed.
As the reflux ratio and the theoretical plate number of the distillation column (vessel), values calculated by a distillation simulator from the physical property values of various components in the raw material can be used. The number of stages of the distillation column (vessel) is usually 2 to 50, preferably 4 to 40, more preferably about 5 to 30.

Since the high boiling point component in the crude glyceryl ether contains a thermally decomposable component, the thermally decomposable high boiling point component is decomposed into a low boiling point odor component and a relatively stable component during distillation. For this reason, the fraction (b) containing the high-boiling component is relatively stable, but the fraction (a) containing the low-boiling component contains the glyceryl ether and the low amount present in the original crude glyceryl ether. A boiling-point odor component and a low-boiling point odor component generated by thermal decomposition of a part of the high-boiling component during distillation are included.
When the dividing tower in the present invention is used, most of the low-boiling odor components present in the crude glyceryl ether and the low-boiling odor components generated by thermal decomposition of a part of the high-boiling components during distillation are low. It is distilled as a fraction (a) containing a boiling component. As a result, contamination with purified glyceryl ether distilled from the middle column of the column is avoided, and purified glyceryl ether with sufficiently reduced off-flavor can be obtained.
The separated purified glyceryl ether is preferably cooled quickly in order to suppress odor degradation due to high temperature, and the temperature after cooling is preferably 50 ° C. or lower.

  As described above, the present invention is characterized in that two types of separation operations, high-boiling component removal and low-boiling component removal, are simultaneously performed using a dividing column. If the removal-high boiling point component removal is performed in this order, the object of the present invention cannot be achieved. That is, in the first distillation column, low-boiling components are discharged from the top of the still, and a fraction containing glyceryl ether and high-boiling components extracted from the bottom of the still is supplied to the second distillation column, Even if high-boiling components are discharged from the bottom of the second distillation column and glyceryl ether is extracted from the top of the second distillation column, some of the high-boiling components are thermally decomposed in the second distillation column. The low-boiling odor component produced in this way is extracted from the top of the second distillation column and mixed in glyceryl ether, so that the odor in the product cannot be reduced.

The purified glyceryl ether thus obtained can be used as a product as it is, but if desired, further known purification operations, for example, purification operations such as washing, recrystallization and column chromatography, and decolorization operations may be performed. it can.
The content of glyceryl ether in the purified glyceryl ether is preferably 80% by weight or more, more preferably 90% by weight or more, and still more preferably 95% by weight or more.

Production Example 1 (Production example of glyceryl ether)
Crude glyceryl ether was synthesized using a continuous tube reactor. 2-ethylhexyl glycidyl ether (gas chromatography purity 99% or more) 74.1 g / min (83.3 cc / min) and 716.7 g / min of ion-exchanged water heated to 280 ° C. are continuously tubular. Feeded to the reactor. The reaction temperature was maintained at 280 ° C., and the reaction pressure was maintained at 8 MPa with a back pressure valve. The flow rate was set so that the residence time inside the reaction tube was 3 min and the molar ratio of water to 1 mol of feedstock was 100 times. The dehydrated product of the reaction product was used as crude glyceryl ether and used as a raw material for distillation.

Example 1
2-ethylhexyl glyceryl ether was converted into a “column-in-column” rectification column (manufactured by Sumiju Plant Engineering Co., Ltd., theoretical plate number 20) (each distillation section A, A ′, B, B ′ in FIG. C and D are 5 stages each), and regular packing SFLOW700G) is used and continuously supplied at 10 kg / h from the raw material supply port 3, the bottom liquid temperature is 180 ° C., the bottom pressure is 0.67 kPa, and low boiling point components are cut. The rectification was performed at a rate of 5.0% (mass basis) and a column reflux ratio of 31. Extraction rate of fraction (a) containing low-boiling components from the top of the column to the outside is 0.5 kg / h, extraction amount of purified products from the middle stage of the column is 9.0 kg / h, high-boiling components from the bottom of the column Steady operation was performed at a discharge rate of 0.5 kg / h to the outside of the fraction (b) containing.
Finally, put 50 ml of the cooled purified product into a glass wide-mouth standard bottle with a capacity of 110 ml, and ask the panelists of 20 to 40-year-olds to smell the odors, and the sensory evaluation criteria shown in Table 1 below The grading score was calculated by rounding off the first decimal place.
As a result, it was found that the odor score of the refined product from the middle stage of the tower was 2 (almost no odor was felt) and it was sufficiently deodorized and could be suitably used for cosmetics and cosmetics. The results are summarized in Table 2.

Comparative Example 1
Crude glyceryl ether was purified using a two-column distillation apparatus 10 shown in FIG.
2-ethylhexyl glyceryl ether was packed with Sulzer Lab Packing DX (manufactured by Sulzer Chemtech Co., Ltd., with the same separation performance as SFLOW 700G of Example 1). The number of theoretical plates was 10 (the distillation units 11 and 12 in FIG. (Five stages) rectification column (column diameter 50 mm) continuously fed at 7.5 g / min, column bottom liquid temperature 150 ° C., column bottom pressure 1.2 kPa, low boiling point component cut rate 4.3% (mass basis) Then, after continuously supplying at a reflux ratio of 10, the bottoms were continuously supplied at a rate of 7 g / min to a rectification column (column diameter 50 mm) having a theoretical plate number of 10 (5 distillation units 13 and 14 in FIG. 2). Then, steady operation was performed at a tower bottom liquid temperature of 132 ° C., a tower bottom pressure of 0.3 kPa, and a high boiling point component cut rate of 6.2% (mass basis).
As a result of sensory evaluation similar to that of Example 1 using the cooled sample, the odor score was 5 (feeling odor) and could not be used for cosmetics and cosmetics. The results are summarized in Table 2.

It is a figure which shows an example of the distillation tower which divided the tower center part using the internal partition plate. 2 is a diagram showing a two-column distillation apparatus used in Comparative Example 1. FIG.

Explanation of symbols

1 Distillation tower (split tower)
2 Internal partition plate 3 Raw material supply port 4 Distillate outlet containing low-boiling components 5 Refined product outlet 6 Distillate outlet containing high-boiling components 7 Condenser at the top of the tower 8 Heater at the bottom of the tower 10 2 towers Distillation equipment

Claims (5)

A purification method using a distillation column having a structure in which the central part of the column is divided into two distillation parts, and a glyceryl ether represented by the following general formula (1) and a low boiling point different from the glyceryl ether as an impurity A crude glyceryl ether containing a component and a high-boiling component is supplied to one of the separated distillation sections at the center of the column, and a fraction containing a low-boiling component (a) and a fraction containing a high-boiling component (b) And a method for purifying glyceryl ether, which is separated into purified glyceryl ether, and the purified glyceryl ether is extracted from the other distillation section.

(In the formula, R represents a substituted or unsubstituted saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, OA represents an oxyalkanediyl group having 2 to 4 carbon atoms, and p represents an average added mole number. The number is 0 to 20, and when p is 2 or more, OA may be the same or different.) The method for purifying glyceryl ether according to claim 1, wherein the glyceryl ether is obtained by hydrolysis of glycidyl ether represented by the following general formula (2).

(In the formula, R, OA, and p are the same as described above.)   The method for purifying glyceryl ether according to claim 1 or 2, wherein the crude glyceryl ether contains 80% by mass or more of glyceryl ether.   The method for purifying glyceryl ether according to any one of claims 1 to 3, wherein the distillation is continuous distillation.   The method for purifying glyceryl ether according to any one of claims 1 to 4, wherein the distillation column is packed with a regular packing.

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