JPS60214757A - Concentration and separation of highly unsaturated fatty acid or its ester - Google Patents

Abstract

PURPOSE:To concentrate and separate the titled compound useful as a preventive and remedy for thrombosis, by using carbon dioxide of liquid or super-critical gaseous state as an extractant, contacting the extractant with a highly unsaturated fatty acid or its ester in the presence of solid urea, and removing carbon dioxide from the extracted phase. CONSTITUTION:A highly unsaturated fatty acid, especially eicosapentaenoic acid, docosahexaenoic acid or various fatty acids containing said lower alcohol ester, or a mixture of lower alcohol esters, is made to contact with carbon dioxide of liquid or super-critical gaseous state in the presence of solid urea, and carbon dioxide is removed from the extracted phase obtained from the contacting zone to effect the concentration and separation of the titled compound. The extraction is carried out preferably under 70-300atm at about 20-40 deg.C lowering the pressure of the extraction phase in two or more steps.

Description

DETAILED DESCRIPTION OF THE INVENTION (Objective) - The present invention is directed to the treatment of highly unsaturated fatty acids, particularly eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), or esters thereof in raw materials containing EPA, The present invention relates to a method for concentrating and separating DHA or esters thereof.

``1'' is trying to ``1'' magazine. It is known that EPA and DHA (and their derivatives such as esters and amides) contained in marine oils and fats such as fish oil are effective in preventing and treating thrombotic diseases such as myocardial infarction and cerebral infarction. However, since the content in natural products is low, it is necessary to concentrate it for various medical and other uses. An object of the present invention is to provide an effective and economical method for concentrating and separating such highly unsaturated fatty acids or their esters.

Conventional Techniques The following terminology is conventionally used as a method for concentrating and separating a specific fatty acid or its ester from a mixture of various fatty acids or its esters: (1) The g distillation method is a high vacuum (1 mm
Hg or less), and because the separation is based on the boiling point difference, highly unsaturated fatty acids or their esters and other fatty acids (
It is difficult to separate it from saturated and low unsaturated fatty acids) or their esters, and distillation alone requires batch distillation, which has the drawback that isomerization and polymerization are likely to occur when exposed to high temperatures for a long period of time.

(2) Chromatography methods generally only handle small amounts, are extremely difficult to scale up, require a long time for separation, are complicated to operate, and have the drawbacks of requiring a large amount of solvent relative to the raw material. .

(3) The urea addition method utilizes the property of fatty acids or their esters with a low degree of unsaturation to add to urea to form crystals, and extracts highly unsaturated fatty acids or their esters from a urea addition mixture with a solvent. This method recovers highly unsaturated fatty acids or their esters from a solution, but if a polar solvent such as methanol is used as an extraction solvent, urea will dissolve and migrate into the extract, so after removing the solvent, the urea must be washed with water or subjected to column chromatography. A process of removing it using An improved method is to use an aliphatic or alicyclic hydrocarbon solvent containing 20% or less methanol (#Kaikai57-164
196) has been proposed, but this method also requires that after solvent extraction,
In order to remove the solvent, it is necessary to perform a separation operation under heat or reduced pressure.

(Structure of the Invention) , 1. The present inventors have discovered that carbon dioxide in a liquid or supercritical gas state selectively extracts highly unsaturated fatty acids or their esters from a urea addition mixture. , completed the invention.

That is, the present invention involves bringing a mixture of various fatty acids or lower alcohol esters containing a highly unsaturated fatty acid or a lower alcohol ester thereof into contact with carbon dioxide in a liquid or supercritical gas state, and solid urea, and producing a mixture obtained from the contact area. This is a method for concentrating and separating highly unsaturated fatty acids or their lower alcohol esters by removing carbon dioxide from the extracted phase.

This method is the same as the conventional urea addition method in that it utilizes the property of a fatty acid with a low degree of unsaturation or its ester to add to urea, but a liquid Alternatively, the invention is novel and inventive in that it uses carbon dioxide in a supercritical gas state.

Since urea does not dissolve in liquid or supercritical gaseous carbon dioxide, the extraction phase consists only of concentrated highly unsaturated fatty acids or lower alcohol esters thereof and carbon dioxide.

The pressure of the extraction step, which is a step of bringing a mixture of various fatty acids or lower alcohol esters containing a highly unsaturated fatty acid or a lower alcohol ester thereof into contact with carbon dioxide in a liquid or supercritical gas state, and solid urea, is 70 to 3.
00 atm, preferably 100 to 250 atm, particularly preferably around 200% pressure. There is no particular restriction on the temperature, but for ease of operation, it is recommended to keep it around room temperature, i.e. 20 to 40℃.
°C is suitable. Under these conditions, carbon dioxide exists in a liquid or supercritical gas state.

In addition, the amount of solid urea used is 1 to 10 times the weight of the various fatty acids or lower alcohol ester mixtures as raw materials.
Particularly preferred is 3 to 8 times the weight.

By heating or depressurizing the extraction phase from this extraction step, the carbon dioxide is rapidly vaporized and can be easily and completely removed, creating a concentrated polyunsaturated fatty acid or its lower alcohol ester that is completely free of urea and solvents. can be separated (separation step).

Furthermore, the separation effect is improved by installing two or more separators, reducing the pressure of the extraction phase in two or more pressure stages, and separating concentrated highly unsaturated fatty acids or their lower alcohol esters in each stage. can be done. This is particularly effective for separating EPA, DHA or their esters.

The carbon dioxide separated in the separation process can be compressed and reused.

Support 1 The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto.

The raw material used in Examples 1 to 6 below was obtained by alkaline decomposition of fish oil with an ethanolic potassium hydroxide aqueous solution. The composition of the fatty acids was determined by converting the fatty acid mixture into methyl esters with anhydrous hydrogen chloride methanol solution, and analyzing the methyl esters by gas chromatography. The composition was expressed as area % on a gas chromatograph.

Example 1 The apparatus shown in FIG. 1 was used. Fatty acids 52.
0g and solid urea 156g (3 times the raw material), carbon dioxide was transferred from pump 2 with pump 3, heated with heater 4 so that the extraction temperature was 25℃, and 200Kg/cm
A constant pressure of 2G was sent to extractor I. Extraction phase is by pressure reducing valve 5
The pressure was reduced to atmospheric pressure in the separator 6, and the carbon dioxide gas from which the extracted oil was separated was measured in the gas meter 7 and discharged to the outside of the system.

The extracted oil collected in the separator 6 was 19.7 g (38 g of the raw material
%)Met. The carbon dioxide content of the raw materials, extracted oil, and raffinate oil was 1.07 Nm' (2,09 Kg), and the extraction time was 1.5 hours.

In the display of fatty acid components in Table 1, for example, 18:2 indicates a fatty acid (linoleic acid) having 18 carbon atoms and 2 double bonds. Eicosapentaenoic acid (EPA) is 2o
:5, and docosahexaenoic acid (DHA) is 22:6.

EPA increased from 18.4% to 22.4%, and DHA increased to 11.
It had increased from 1% to 13.6% [16].

Example 2 The same raw fatty acid mixture and the same equipment as in Example 1 were used. 35.1 g of fatty acids and 18 Ig of solid urea (raw material 5
．． 2 times) and put it in extractor 1, 25℃, 200K.
g/Cm2c't'o, 64Nm" (1,24Kg
) was extracted with carbon dioxide for 1.5 hours, and the extracted oil to, t
g (29% of raw material) was obtained. Composition analysis values are shown in Table 2.

Table 2 EPA increased from 18.4% to 29.4%, DMA increased to 11.
It was concentrated from 1% to 21.5%.

Example 3 Separation pressure of extracted oil was changed in two steps using the apparatus shown in FIG. 2. Raw fatty acid 34.7g and solid urea 181g
g (5.2 times the raw material) and put it into the extractor l,
Extraction with carbon dioxide was performed at 0°C and 200Kg/cm2G. The pressure of the extraction phase is reduced to 120 kg/cm2G by a pressure reducing valve 5a, and a portion of the extracted oil is separated by a separator 6a. 6a
The carbon dioxide containing the extracted oil that was not separated is further reduced in pressure to atmospheric pressure in the pressure reducing valve 5b, and the extracted oil is completely separated in the separator 6a. In this way, 0.74Nm3 (
1,54Kg) t7) Extraction using carbon dioxide over 1.5 hours resulted in 6.8g (20% of the raw material) in the separator 6a and 5.7g (17% of the raw material) in the separator 6b. An extracted oil was obtained. The results of the compositional analysis are shown in Table 3.

In the extracted oil collected in separator 6a, EPA is lj'l
-A Qi) Chi 30-3%, DNA from 11.1% to 2
It was concentrated to 5.0%. Also, in the extracted oil collected in the separator 6b, EPA is 28.3% and DHA is 17.3%.
It was concentrated to %.

Table 3 Examples 4 to 6 The weight of solid urea relative to the raw fatty acid mixture was 1.0 times (Example 4), 2.9 times (Example 5), and 8.2 times (Example 6), respectively. Extraction with carbon dioxide was performed at 40° C. and 200 Kg/Cm 3 in the same manner as in Example 3, except for the following. The concentrations of EPA and DHA contained in the extracted oil and raffinate oil at this time, including the case of Example 3,
They are shown in FIGS. 3 and 4, respectively.

In Fig. 3, the horizontal axis is the usage ratio of solid urea to the raw fatty acid mixture, and the vertical axis is the usage ratio of eicosapentaenoic acid (E P
The concentration (%) of A) is shown, and the O mark indicates the concentration (%) of separator 6a (120
Kg/cm2G), the 0 mark indicates the EPA concentration in the extracted oil collected by the separator 6b (atmospheric pressure), and the Δ mark indicates the raffinate oil.

In addition, the horizontal axis in Figure 4 is the usage ratio of solid urea to the raw fatty acid mixture, and the vertical axis is docosahexaenoic acid
), and the O mark indicates the concentration (%) of separator 6a (120,
Kg/am2G), the 0 mark indicates the DMA concentration in the extracted oil collected by the separator 6b (atmospheric pressure), and the Δ mark indicates the raffinate oil concentration.

It has been shown that the higher the ratio of urea, the better the separation efficiency, and it becomes almost constant at about 8 times the weight.

Example 7 57.9 g of a methyl ester mixture prepared from fish oil in methanol using sodium methoxide as a catalyst and solid urea Z7O (2.9 times the amount of SGC methyl ester) were placed in the extractor shown in Figure 2 and extracted. The temperature was 40°C, the extraction pressure was 150 Kg/cm2G, the pressure of separator 6a was 100Kg/cm2G, the pressure of separator 6b was atmospheric pressure, and 0.26Nm3 (0.51'g) of carbon dioxide was added. When extraction was carried out for 1 hour using
g (35% of the raw material), 9.8 g (17% of the raw material) of extracted oil was obtained in separator 6b. Composition analysis values are shown in Table 4.

In the extracted oil collected in the separator 6a, the methyl ester of EPA was concentrated from 14.7% to 25.8%, and the methyl ester of DMA was concentrated from 12.2% to 19.6%. Furthermore, in the extracted oil collected by the separator 6b, EPA methyl ester was concentrated to 22.2%, and DHA methyl ester was concentrated to 13.4%.

Table 4 Example 8 42.0 g of the same methyl ester mixture as in Example 7 and 253.3 g of solid urea (6.0 times the amount of methyl ester) were placed in the extractor shown in Figure 2, and the extraction temperature was 40'C. ! , extraction pressure 200Kg/cm2G, pressure of separator 6a 120
Kg/cm2G, assuming the pressure of the separator 6b to be atmospheric pressure, 0
．． 15Nm3 (0.

When extracted using carbon dioxide (29 kg) for about 1 hour, 15.1 g (36% of the original size) was found in the separator 6a.
, 5.0 g (12% of the raw material) of extracted oil was obtained in separator 6b. Composition analysis values are shown in Table 5.

Table 5 In the extracted oil collected by separator 6a, methyl ester of EPA was concentrated from 14.7% to 26.2%, and methyl ester of DHA was concentrated from 12.2% to 20.0%. . Also, in the extracted oil collected by the separator 6b, EPA methyl ester was concentrated to 24.3% and DHA methyl ester was concentrated to 16.2%.

(Effects) a) Carbon dioxide used as a solvent is inexpensive and harmless to the human body.

b) Since urea is not extracted with carbon dioxide and the solvent carbon dioxide can be easily and completely removed from the extraction phase, highly unsaturated fatty acids or their esters can be effectively extracted from fatty acids or their esters made from natural fats and oils. Can be concentrated and separated.

C) Since extraction can be carried out at low temperatures, isomerization and polymerization of highly unsaturated fatty acids are unlikely to occur.

[Brief explanation of drawings]

Figure 1 is a diagram showing the apparatus used in Examples 1 and 2;
The figure shows the equipment used in Examples 3 to 8. Figure 3 shows the amount of eicosapentaenoic acid (EPA) in the concentrated isolate when the usage ratio of solid urea to the raw fatty acid mixture was changed.
Figure 4 is a diagram showing changes in the concentration of docosahexaenoic acid (DHA) in the concentrated isolate when the usage ratio of solid urea to the raw fatty acid mixture was changed. Applicant JGC Co., Ltd. Company agent Patent attorney Masa Aoma 2nd 1st cause 21st! 1st

Claims (1)

[Claims] 1. Various fatty acids containing a highly unsaturated fatty acid or a lower alcohol ester thereof, or a mixture of lower alcohol esters thereof, carbon dioxide in a liquid or supercritical gas state, and solid urea are brought into contact, and the contact area A method for concentrating and separating highly unsaturated fatty acids or their lower alcohol esters, which comprises removing carbon dioxide from the extracted phase obtained from 2 The highly unsaturated fatty acid is eicosapentaenoic acid (EPA
) or docosahexaenoic acid (DHA). 3 Extraction pressure is 70-300 atm, extraction temperature is 20-4
The method according to claim 1 or 2, wherein the temperature is 0°C. 4 Reduce the pressure of the extraction phase in two or more pressure stages to -LA+
12jJ U MFI'L 7--a3m(db"th-+
J-1 white rRFfh'>1 (1Rk connbMT) is claimed in claim 1 to separate its lower alcohol ester.
3. The method described in Section 2, Section 2, or Section 3.