JP2742569B2 - Method for separating polyunsaturated fatty acid ester having double bond at ω3 position and ω6 position - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for separating a highly unsaturated fatty acid ester having at least ω3 and ω6 double bonds from a mixture of unsaturated fatty acid esters derived from fats and oils. .

(Prior art and its problems) Polyunsaturated fatty acids having a double bond at the ω3 and ω6 positions such as γ-linolenic acid, eicosapentaenoic acid, and docohexosaenoic acid are called essential fatty acids, and are considered as essential fatty acids. It is essential for maintenance, but cannot be biosynthesized in the animal body, so it must be taken from the outside.

Such essential fatty acids are present in the form of triglycerides in fats and oils such as fish oils, vegetable oils and fungus body oils. As a method for separating an essential fatty acid component from fats and oils, a fat and oil is subjected to a transesterification reaction to form a fatty acid ester mixture, and this mixture is then subjected to a urea adduct method (Japanese Patent Application No. 57-187397).
No., JP-A-58-8037, JP-A-60-133094, JP-A-62
-72793), a crystallization method (Japanese Patent Application Laid-Open No. 59-67241, etc.) and a distribution chromatographic method (Japanese Patent Application Laid-Open No. 60-208940) have been proposed, but from the industrial point of view. It was not yet a satisfactory method. That is, in the urea adduct method, it is difficult to obtain a high-purity product because the separation coefficient of the target substance is small. The crystallization method is economically disadvantageous because it needs to be cooled to an extremely low temperature, and it is difficult to obtain a high-purity product because the separation factor of the target product is low. In the distribution chromatography, the adsorption capacity of the column is small, and it is necessary to use a large amount of an expensive column, and there is a problem that the product is diluted with an eluent, so that it cannot be a practical method.

According to JP-A-63-264555, an adsorption separation method using a zeolite adsorbent has been proposed for separating γ-linolenic acid ester. However, in this separation method, since the operation method is a batch type, the amount of the adsorbent and the desorbent is much larger than that of a product which can obtain the required amount, and the operation is complicated, so that it cannot be said that this method is industrially advantageous. Further, the continuous adsorption separation method of fatty acid esters is described in, for example, JP-A-54-119503, JP-A-55-136248, and the like, but these separation methods are only included from the fatty acid ester mixture. It is intended to separate saturated fatty acid components with high purity and does not disclose separation of essential fatty acid components.

(Problems of the Invention) The present invention provides a method for separating a high-purity unsaturated fatty acid ester having a double bond at least in the ω3 and ω6 positions contained therein from a mixture of unsaturated fatty acid esters derived from fats and oils. Make it an issue.

(Means for Solving the Problems) The present inventors have conducted intensive studies to solve the above problems, and as a result, have completed the present invention.

That is, according to the present invention, in separating a highly unsaturated fatty acid ester having a double bond at least at the ω3 and ω6 positions contained therein from the unsaturated fatty acid ester mixture derived from fats and oils, it is separated from the unsaturated fatty acid ester mixture. The same fraction having the same carbon number is introduced into a simulated moving bed adsorption / separation apparatus containing a faujatoite type zeolite adsorbent substituted with a group IA metal cation and a desorbent represented by the following general formula (I) or (II). Contacting the adsorbent and the desorbent, and separating the polyunsaturated fatty acid ester having a double bond at least at the ω3 position and the ω6 position as an extract from the adsorption separation device as an extract.
A method for separating a highly unsaturated fatty acid ester having a double bond at the 6-position is provided.

(Wherein R ¹ and R ² are hydrogen or a lower alkyl group) R ³ —O—R ⁴ (II) (wherein R ³ and R ⁴ are a lower alkyl group) And unsaturated fatty acid ester mixtures derived from fats and oils. Such a raw material can be obtained by hydrolyzing an oil or fat and then esterifying it, or by directly transesterifying the oil or fat. In this case, examples of the unsaturated fatty acid ester include alkyl esters such as methyl ester, ethyl ester, propyl ester and butyl ester. The fats and oils, sardine oil, fish oil such as herring oil, evening primrose oil,
Vegetable oils such as palm oil, and cell oils obtained from cells such as Mortierella spp. And Aspergillus spp.

In the present invention, first, the unsaturated fatty acid ester mixture has the same carbon number as the desired highly unsaturated fatty acid ester component having a double bond at the ω3 and ω6 positions (hereinafter, also simply referred to as an essential fatty acid ester component). Separate the fractions. For this separation, a conventionally known method such as a distillation treatment or a solvent extraction method can be employed. The separation of the same carbon fraction is carried out by separating 90% by weight of fatty acid ester components having the same carbon number.
This is performed so as to be at least 95% by weight or more.

Next, the fraction having the same carbon number separated in this way is
This is introduced into a simulated moving bed adsorption / separation device containing an adsorbent and a desorbent to perform an adsorption / separation treatment, and an essential fatty acid ester is separated as an extract. This extract is composed of an essential fatty acid ester and a desorbing agent, and the essential fatty acid ester can be recovered by subjecting the extract to a distillation treatment.

In the adsorptive separation of the same carbon fraction, a faujasite-type zeolite adsorbent substituted with at least one metal cation selected from Group IA metals is used.

This faujasite-type zeolite is a crystalline aluminosilicate represented by the following general formula.

0.9 ± M ₂ O: Al ₂ O ₃ : xSiO ₂ : yH ₂ O In the above formula, M is a Group IA metal cation, and examples thereof include sodium, potassium and lithium. Faujasite type zeolites are classified into X type and Y type, and in the case of X type,
X is 2.5 ± 0.5, and for Y type, x is 3-6.
y varies depending on the degree of hydration, but generally ranges from 0 to 9.

The faujasite-type zeolite used in the present invention may be partially modified in its structure, for example, may be subjected to a dealumination treatment, and may contain another metal depending on the case. In the present invention, the use of a Y type is preferred. The faujasite-type zeolite used in the present invention needs to be substituted with a Group IA metal cation. When a material substituted with a polyvalent metal ion such as calcium or magnesium is used, a polymerization reaction of an unsaturated fatty acid ester occurs at the time of adsorptive separation, and good results cannot be obtained.

As the desorbing agent in the present invention, a compound represented by the general formula (I) or (II) is used. It is also effective to use a mixture of both. Even if alcohols and esters are used, effective separation of essential fatty acid esters cannot be performed.

Examples of the desorbing agent represented by the general formula (I) include benzene, toluene, xylene, ethylbenzene,
Isopropylbenzene, n-propylbenzene and the like can be mentioned. Examples of the desorbing agent represented by the general formula (II) include dimethyl ether, diethyl ether, diisopropyl ether, methyl ethyl ether and the like.

According to the study of the present inventors, the above-mentioned general formulas (I) and (I)
It has been found that the adsorption strength and desorption strength of the compound represented by I) with respect to the zeolite adsorbent are not too strong and not too weak, respectively, as compared with the essential fatty acid ester, and have excellent properties as a desorbent. Was done.

The adsorption separation in the present invention is performed by a simulated moving bed system. Adsorption separation by the simulated moving bed method is an already established technique, which is applied to adsorption separation of a xylene isomer mixture, for example, Japanese Patent Publication No. 42-15681,
It is described in Japanese Patent Publication No. 50-10547. In such an adsorption separation technique, an extract comprising an essential fatty acid ester and a desorbing agent is obtained, and a raffinate comprising a fatty acid ester component other than the essential fatty acid ester and a desorbing agent is obtained. These extracts and raffinates are subjected to a distillation treatment and separated into respective components, and the separated desorbent is recycled again.

Next, the adsorption separation technique by the simulated moving bed method will be described in more detail. This adsorption separation technique continuously circulates the following adsorption operation, concentration operation, desorption operation and desorbent recovery operation as basic operations. Will be implemented.

(1) Adsorption operation: The mixture containing the essential fatty acid ester comes into contact with the adsorbent, the essential fatty acid ester is selectively adsorbed as the strongly adsorbed component, and the other component, which is the weakly adsorbed component, is recovered together with the desorbent as a raffinate stream. Is done.

(2) Concentration operation: The adsorbent selectively adsorbing the essential fatty acid ester is brought into contact with a part of the extract described later, and the weakly adsorbed component remaining on the adsorbent is expelled, and the essential fatty acid ester is removed. It is concentrated.

(3) Desorption operation: The adsorbent containing the concentrated essential fatty acid ester is brought into contact with the desorbent, the essential fatty acid ester is expelled from the adsorbent, and is recovered as an extract stream with the desorbent.

(4) Adsorbent recovery operation: The adsorbent having substantially adsorbed only the adsorbent comes into contact with a part of the raffinate stream, and a part of the desorbent contained in the adsorbent is recovered as a desorbent recovery stream.

FIG. 1 shows a schematic diagram of an adsorption separation apparatus using a simulated moving bed. In this figure, 1 to 12 are adsorption chambers containing an adsorbent, which are connected to each other. 13 is a desorbent supply line,
14 is an extract extraction line, 15 is a raw material supply line,
16 indicates a raffinate extraction line, and 17 indicates a recycling line. In the arrangement state of the adsorption chambers 1 to 12 and the respective lines 13 to 16 shown in the drawing, a desorption operation is performed in the adsorption chambers 1 to 3, a concentration operation is performed in the adsorption chambers 4 to 7, an adsorption operation is performed in the adsorption chambers 7 to 10, and the adsorption chamber 11 The desorbent recovery operation is performed at ~ 12.

In such a simulated moving bed adsorption / separation apparatus, each supply and withdrawal line is moved by one valve in the liquid flow direction at regular time intervals by operating a valve. Therefore, in the next arrangement state of the adsorption chambers, the desorption operation in the adsorption chambers 2 to 4, the concentration operation in the adsorption chambers 5 to 7, the adsorption operation in the adsorption chambers 8 to 11, and the desorbent recovery operation in the adsorption chambers 12 to 1, respectively. Will be done. By performing such operations sequentially,
An adsorption separation process is achieved. It should be noted that in the drawings, the number of the suction chambers is specified to be 12, but the number of the suction chambers is not limited.

Next, specific operating conditions when performing adsorption separation by a simulated moving bed will be described.

(I) Desorption operation zone L (I) / S (I)> 0.3A + L (IV) / S (IV) (where L (I) is the liquid flow rate (cc / h) flowing through the desorption operation zone
r) and S (I) are the adsorbent flow rates (c
c / hr), L (IV) is the liquid flow rate (cc) flowing through the desorbent recovery zone.
/ hr) and S (IV) indicate the adsorbent flow rate (cc / hr) moving through the desorbent recovery zone.) (ii) Concentration operation zone L (II) / S (II)> 0.1 / A + L (IV) / S (IV) (where L (II) is the liquid flow rate (cc / h
r) and S (II) are the adsorbent flow rates (c
(iii) C / hr) (iii) Adsorption operation zone L (III) / S (III) <0.6A + L (IV) / S (IV) (where L (III) is the liquid flow rate flowing through the adsorption operation zone) (Cc /
hr) and S (III) indicate the flow rate (cc / hr) of the adsorbent moving in the adsorption operation zone.) (iv) Desorption agent recovery operation zone 0.8 <L (IV) / S (IV) <1.3 , L (IV) indicates the liquid flow rate (cc / hr) flowing through the desorbent recovery operation zone, and S (IV) indicates the adsorbent flow rate (cc / hr) moving through the desorbent recovery operation zone. The value of A is 1.0 to 5.0 when separating ethyl eicosapentaenoic acid; 0.5 to 3.0 when separating ethyl docosahexaenoic acid; γ
-When separating linolenic acid ethyl ester: 1.0 to
The value is 4.2, which is determined appropriately by preliminary experiments.

The temperature in the adsorption separation is 30 to 200 ° C., preferably 60
100100 ° C. and pressure is normal pressure 常 50 kg / cm ² G, preferably 3
Is a ~30kg / cm ² G.

(Effects of the Invention) According to the present invention, an essential fatty acid ester contained in a mixture of unsaturated fatty acid esters derived from fats and oils can be efficiently and continuously purified with high purity.

(Example) Next, the present invention will be described in more detail with reference to examples.

The relative separation coefficients β (IA / i) and β (IA / D) based on the essential fatty acid ester (IA) used as indices indicating the adsorption characteristics of the adsorbent are each the component i
And for the desorbing agent and are represented by the following formula:

β (IA / i) = K (IA) / K (i) β (IA / D) = K (IA) / K (D) where K (IA), K (i) and K (D) Are solid-liquid equilibrium constants of an essential fatty acid ester, an i component, and a desorbing agent, respectively, and are defined by the following equations.

When the relative separation coefficient β (IA / i) indicates a value larger than 1, it means that the essential fatty acid ester is more strongly adsorbed to the adsorbent than the mixed component i. Conversely, a mixed component i in which β (IA / i) is close to or less than 1 indicates that the adsorbent adsorbs to the adsorbent at a level equal to or stronger than the essential fatty acid ester. From the viewpoint of separating the essential fatty acid ester with high purity, the relative separation coefficient β (IA / i) is preferably a value that is at least twice the relative separation coefficient of the essential fatty acid ester.

Reference Example 1 (1) Transesterification 15 kg of sardine oil or Mortierella cell oil (triglyceride) and 1.5 kg of ethanol were mixed, and 30 g of sodium ethylate was added as a catalyst to the mixture.
For about 2 hours.

Next, the obtained reaction product was mixed with about 3.0 kg of saturated saline, and an oil phase composed of a higher fatty acid ethyl ester mixture was collected. Table 1 shows the result of measuring the composition of the higher fatty acid ethyl ester mixture obtained from the sardine oil by gas chromatography. Table 2 shows the results of measuring the composition of the higher fatty acid ethyl ester mixture obtained from Mortierella cell oil by gas chromatography.

In addition, "CX: y" shown in Table-1, Table-2 and below
Represents an ethyl ester of a fatty acid having X carbon atoms and having y unsaturated bonds. Therefore, EPA (eicosapentaenoic acid) ethyl ester is represented by “C20: 5”, and DHA (docosahexaenoic acid) ethyl ester is represented by “C22:
5 '', and γ-linolenic acid ethyl ester is represented by `` C1
8: 3 ".

(2) Adsorption experiment Adsorption experiments were performed as follows using the mixture of fatty acid ethyl esters derived from sardine oil or Mortierella cell oil shown in Tables 1 and 2 obtained by the transesterification.

2 g of each ester mixture, 6 g of isooctane as diluent
Then, 4 g of sodium-type Y-type zeolite was placed in an Erlenmeyer flask as an adsorbent, stirred well, and allowed to stand overnight. Next, after collecting a sample of the liquid phase (raffinate), the liquid phase in the flask was discarded, and isooctane was charged to wash and remove the ethyl ester not adsorbed on the zeolite. Finally, ethanol was charged into the flask to desorb the ethyl ester mixture adsorbed on the zeolite.
All the liquid phases in the flask were collected in a beaker, and then the ethanol was added to the flask to wash the zeolite, and the liquid phase in the flask was collected in a beaker again to remove all the adsorbed ethyl ester mixture. Collected in a beaker. The liquid phase in the beaker was used as an extract, and the composition of the raffinate previously collected and the composition of the extract were measured by gas chromatography, and the relative separation coefficient was determined based on the measurement result.
The results are shown in Tables 3 and 4. Table 3 shows the results for sardine oil esters, and Table 4 shows the results for bacterial oil esters.

From the results shown in Tables 3 and 4, among fatty acid esters having the same number of carbon atoms, the fatty acid ester having a larger number of unsaturated bonds has stronger adsorption, and also has the same number of unsaturated bonds but different numbers of carbon atoms. It can be seen that the adsorption force is different. Therefore, in order to separate the essential fatty acid esters ethyl γ-linolenate, ethyl eicosapentaenoate and ethyl docosahexaenoate from these mixtures at a high purity, the same number of carbon atoms is determined in advance by a method such as distillation or solvent extraction. It turns out that it is indispensable to separate into components rich in fatty acid esters.

(4) Distillation Treatment 1.0 kg of each of the higher fatty acid ethyl ester mixtures shown in Tables 1 and 2 was subjected to a distillation treatment using a batch distillation apparatus packed with McMahon packing having an inner diameter of 20 mm and a height of 180 mm. The pressure during distillation was 1 mmHg, and the reflux ratio was 20. As a result, from the ethyl ester mixture obtained from sardine oil,
170 g of an ethyl ester mixture of fatty acids having 20 carbon atoms (C20 fraction) and 103 g of an ethyl ester mixture of fatty acids having 22 carbon atoms (C22 fraction) were obtained. Tables 5 and 6 show the results of measuring the composition of these fractions by gas chromatography.

In addition, from the ethyl ester mixture 1.0 kg obtained from Mortierella cell oil in the same manner, a fraction having 18 carbon atoms is about 100 g.
Obtained. Table 7 shows the results of measuring the composition of the fatty acid ester mixture having 18 carbon atoms by gas chromatography.

Reference Example 2 (1) EPA ethyl ester (C
20: 5), 2 g of the C20 fraction, 2 g of the desorbent, and 2 g of the diluent (isooctane) shown in Table 5 above were placed in an Erlenmeyer flask, and a faujasite-type ion was used. 4 g of Y-type zeolite in which the exchange metal species was Na was charged into this flask, stirred well, and allowed to stand overnight. Next, after collecting a liquid phase sample (raffinate),
Discard the liquid phase in the flask, add isooctane,
The ethyl ester not adsorbed on the zeolite was washed and removed. Finally, ethanol was charged into the flask to desorb the ethyl ester mixture adsorbed on the zeolite. All the liquid phases in the flask are collected in a beaker, and then the ethanol is added to the flask to wash the zeolite, and the liquid phase in the flask is collected in a beaker again to remove all the adsorbed ethyl ester mixture. Collected in a beaker. The liquid phase in this beaker was used as an extract, and the composition of the raffinate collected earlier and the composition of this extract were measured by gas chromatography. Based on these measurement results, the relative separation coefficient β of each component was calculated based on EPA ethyl ester (C20: 5). The results are shown in Table-8. In addition, the adsorption capacity of the adsorbent was 0.2 to 0.3 g / g.

(2) DHA ethyl ester (C2
2: 6), the C22 fraction shown in Table 6 above was used to determine the relative separation coefficient of the C22 component based on the above (1).
An adsorption test was performed in the same manner as described above. The results are shown in Table-9. The adsorption capacity at this time was about 0.3 g / g.

(3) To determine the relative separation coefficient of C18 component based on γ-linolenic acid ethyl ester (C18: 3),
Using the C18 fraction shown in No. 7, an adsorption test was performed in the same manner as in the above (1). Table 10 shows the results. The adsorption capacity at this time was 0.3 g / g.

Comparative Reference Example EPA ethyl ester, D
Adsorption experiments were performed using three kinds of oils including HA ethyl ester and γ-linolenic acid ethyl ester as raw material oils, and using ethanol, cyclohexanol, propyl acetate and diethyl ketone as desorbents. When these desorbents were used, almost no essential fatty acid ester was present in the extract, and it was confirmed that the adsorptive power of the desorbent was too strong to be unsuitable as a desorbent in the present invention.

Example 1 The adsorptive separation of the C20 fraction shown in Table-5 was carried out using the simulated moving bed continuous adsorptive separator shown in FIG. 1, and EPA ethyl ester was separated as an extract from the raw material mixture.

In the apparatus shown in FIG. 1, adsorbents shown in Reference Example 1 were packed in adsorbent columns 1 to 12 each having an internal volume of 20 cm ³ . The feedstocks shown in Table 5 were supplied from line 15 at 100 cm ³ / hr, and the desorbent (mixture of benzene and p-xylene) was supplied from line 13 at 159 cm ³ / hr. The extract was extracted from line 14 at 129 cm ³ / hr, and the raffinate was extracted from line 16 at 129 cm ³ / hr. At this time, column 1 was moved to 2, 11 to 10, 7 to 6, and 4 to 3 at an interval of 497 seconds. The adsorption temperature was 40 ° C., and the pressure was 5 kg / cm ² G.
At this time, the concentration of EPA ethyl ester in the extract was about 10 wt%, and the recovery of EPA ethyl ester was 98%.

Next, the desorbent was removed from the obtained extract by distillation to obtain a product EPA ethyl ester. EPA in products
The concentration of the ethyl ester was 99% by weight or more.

Example 2 The adsorptive separation of the C22 fraction shown in Table-6 was carried out using the simulated moving bed continuous adsorptive separator shown in FIG. 1 to separate DHA ethyl ester as an extract from the raw material mixture.

In the apparatus shown in FIG. 1, adsorbents shown in Reference Example 1 were packed in adsorbent columns 1 to 12 each having an internal volume of 50 cm ³ . The feedstocks shown in Table 6 were supplied from line 15 at 100 cm ³ / hr, and the desorbent (mixture of benzene and diisopropyl ether) was supplied from line 13 at 280 cm ³ / hr. The extract was extracted from line 14 at 151 cm ³ / hr, and the raffinate was extracted from line 16 at 229 cm ³ / hr. At this time 463
At intervals of 2 seconds, column 1 is 2, 11 is 10, 7 is 6, 4 is 3.
Was moved at the same time. Adsorption temperature is 40 ℃, pressure is 5kg / cm ³ G
Met. At this time, the concentration of DHA ethyl ester in the extract was about 10 wt%, and the recovery of DHA ethyl ester was 98%.

Next, the desorbing agent was removed from the obtained extract by distillation to obtain a product DHA ethyl ester. DHA in product
The concentration of the ethyl ester was 99% by weight or more.

Example 3 The adsorptive separation of the C18 fraction shown in Table 7 was carried out using the simulated moving bed continuous adsorptive separator shown in FIG. 1, and γ-linolenic acid ethyl ester was extracted from the raw material mixture as an extract. separated.

In the apparatus shown in FIG. 1, adsorbents shown in Reference Example 1 were packed in adsorbent columns 1 to 12 each having an internal volume of 20 cm ³ . The feedstocks shown in Table 7 were supplied from line 15 at 100 cm ³ / hr, and the desorbent (benzene) was supplied from line 13 at 145 cm ³ / hr. The extract was extracted from line 14 at 129 cm ³ / hr, and the raffinate was extracted from line 16 at 115 cm ³ / hr. At this time, column 1 is changed to 2 and 11 is changed to 10
, 7 and 6, 4 and 3 were simultaneously moved. The adsorption temperature is
At 40 ° C., the pressure was 5 kg / cm ² G. At this time, the concentration of γ-linolenic acid ethyl ester in the extract was about
10 wt%, and the recovery of ethyl linolenic acid ethyl ester was 98%.

Next, the desorbing agent was removed from the obtained extract by distillation to obtain a product γ-linolenic acid ethyl ester.
The concentration of γ-linolenic acid ethyl ester in the product is 99wt%
That was all.

[Brief description of the drawings]

FIG. 1 is a schematic view of an adsorption separation apparatus using a simulated moving bed. 1-12 Adsorption chamber 13 Desorbent supply line 14 Extract extraction line 15 Raw material mixture supply line 16 Raffinate extraction line 17 Recycle line 18 Pump

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiya Hirohama 63-2 Higashikawashima-cho, Hodogaya-ku, Yokohama, Kanagawa Prefecture (56) References JP-A-63-264555 (JP, A) JP-A-63-290845 (JP, A) JP-A-54-119503 (JP, A) JP-A-2-145695 (JP, A)

Claims (2)

(57) [Claims] 1. A method for separating a highly unsaturated fatty acid ester having a double bond at least at the ω3 and ω6 positions contained therein from the mixture of unsaturated fatty acid esters derived from fats and oils, wherein the same is separated from the unsaturated fatty acid ester mixture. The carbon number fraction is introduced into a simulated moving bed adsorption / separation apparatus containing a faujatoite type zeolite adsorbent substituted with a group IA metal cation and a desorbent represented by the following general formula (I) or (II). And contacting with a desorbing agent, and separating the polyunsaturated fatty acid ester having a double bond at least at the ω3 and ω6 positions from the adsorption separation device as an extract. A method for separating a highly unsaturated fatty acid ester having the same. (Wherein R ¹ and R ² are hydrogen or a lower alkyl group) R ³ —O—R ⁴ (II) (where R ³ and R ⁴ are a lower alkyl group) 2. The method according to claim 1, wherein the polyunsaturated fatty acid ester to be separated is γ-linolenic acid ester, eicosapentaenoic acid ester or dochexaenoic acid ester.