阅读说明：本技术 一种高含量共轭亚油酸甘油三酯及其制备方法 (High-content conjugated linoleic acid triglyceride and preparation method thereof ) 是由 姜书华 洪永德 周丽平 徐维峰 于 2018-08-22 设计创作，主要内容包括：本发明涉及共轭亚油酸甘油三酯的制备,特别是一种高含量共轭亚油酸甘油三酯及其制备方法。本发明通过在红花油甲酯异构化前用结晶提纯方法把亚油酸含量提高到95％以上,然后通过酯化反应得到高纯度、高含量的共轭亚油酸甘油三酯。本发明工艺简单,无需碱催化转位步骤,相比于传统工艺可极大减少共轭亚油酸在提纯过程中的损失,降低成本；另外,先提纯亚油酸再进行共轭化的反应可以保证共轭亚油酸甘油三酯两种同分异构体(c9,t11-CLA)和(t10,c12-CLA)的比例在保持1:1,本发明提纯方式采用结晶提纯结合高真空精馏的方法,使亚油酸提纯到95％以上,具有良好应用前景,适合规模化应用。(The invention relates to preparation of conjugated linoleic acid triglyceride, in particular to high-content conjugated linoleic acid triglyceride and a preparation method thereof. The invention increases the linoleic acid content to more than 95 percent by a crystallization purification method before the isomerization of the safflower oil methyl ester, and then obtains the conjugated linoleic acid triglyceride with high purity and high content by esterification reaction. The method has simple process, does not need the step of alkali-catalyzed transposition, and can greatly reduce the loss of the conjugated linoleic acid in the purification process and reduce the cost compared with the traditional process; in addition, the linoleic acid is purified and then conjugated, so that the proportion of two isomers (c9, t11-CLA) and (t10, c12-CLA) of the conjugated linoleic acid triglyceride can be kept at 1:1, and the purification method adopts a method of crystallization purification and high vacuum rectification, so that the linoleic acid is purified to more than 95 percent, has good application prospect and is suitable for large-scale application.)

1. A preparation method of high-content conjugated linoleic acid triglyceride is characterized by comprising the following steps:

s1, crystallization and purification

Placing safflower oil methyl ester at-16-4 deg.C, maintaining for more than 10 hr, filtering at low temperature to separate crystal and filtrate;

s2, rectification and purification

Connecting a thin film evaporator at the bottom of the rectifying tower, wherein the height of the tower is more than 1m, the number of theoretical plates is not less than 30, controlling the temperature of the thin film evaporator to be more than 200 ℃, keeping vacuum stability for 30min after reflux appears at the top of the tower, starting a condenser at the top of the tower, setting the reflux ratio to be at least 3:1, and collecting fractions to obtain purified safflower oil methyl ester;

s3. conjugation reaction

Under the vacuum condition, adding a potassium methoxide methanol solution with the mass of 10 percent of that of the safflower oil methyl ester dropwise into the purified safflower oil methyl ester, heating to 105-110 ℃ for conjugation reaction to obtain conjugated linoleic acid methyl ester;

s4, esterification reaction

Adding glycerol triacetate with the mass 0.22 time that of safflower oil methyl ester into conjugated methyl linoleate to mix, heating to 90 ℃ under the protection of nitrogen to react, then dropwise adding sodium methoxide methanol solution with the mass 3.0% of safflower oil methyl ester, heating to 130-135 ℃, keeping the temperature to react for 7-10h, washing after the reaction is finished until the pH value of a water layer is 6-7, heating to 80 ℃, and removing water;

s5, collecting

Starting a heat transfer oil system, controlling the temperature of the reaction kettle at 175-190 ℃, the system pressure at less than 20Pa, the feeding temperature at 100-120 ℃, and the feeding amount at 60-140L/h, and collecting the heavy components to obtain the conjugated linoleic acid triglyceride.

2. The method according to claim 1, wherein said step S1 of purifying safflower oil methyl ester is carried out at a low temperature of 2 ℃.

3. The method according to claim 1, wherein the conjugation reaction of step S3 is specifically: under the vacuum condition, adding a potassium methylate methanol solution which is 10 percent of the mass of the safflower oil methyl ester into the purified safflower oil methyl ester dropwise, heating to 105-110 ℃, cooling to 80 ℃ after the reaction is qualified, adding methanol, cooling to 45 ℃, adjusting the pH to 7-8, adding sodium bisulfate which is 2 percent of the mass of the safflower oil methyl ester, starting steam, heating and refluxing, and removing the catalyst sodium bisulfate to obtain the conjugated linoleic acid methyl ester.

4. The method of claim 1, wherein in the step S3, during steam heating reflux, the steam pressure is controlled to be less than 2.0MPa, the reflux temperature is controlled to be 65-75 ℃, and after the reaction is continued for 1h, the catalyst sodium bisulfate is removed.

5. The method according to claim 1, wherein the esterification reaction of step S4 is specifically: adding glycerol triacetate 0.18-0.25 times of safflower oil methyl ester into conjugated linoleic acid methyl ester, mixing, vacuumizing, and controlling nitrogen flow to be 15-20m³Heating to 90 ℃, dropwise adding a sodium methoxide methanol solution with the mass of 2.5-4.0% of safflower oil methyl ester, heating to 130-.

6. The method according to claim 1, wherein in step S3, the method for removing the catalyst sodium bisulfate is specifically as follows: distilling out methanol at normal pressure, simultaneously replenishing methanol into the kettle, heating until reflux appears in the kettle, continuing to react for 1h, adding water which is 0.3 times of the weight of the safflower oil methyl ester into the kettle, stirring for 20 min, standing to separate an acid water layer, adding water which is 0.2 times of the weight of the safflower oil methyl ester into the kettle each time, and stirring for 20 min until the Ph of the water layer is 6-7. Stirring, heating to 100 deg.C, and removing water under reduced pressure.

7. A conjugated linoleic acid triglyceride produced according to the method of claim 1.

8. The conjugated linoleic acid triglyceride according to claim 7, wherein the ratio of the two isomers (c9, t11-CLA) and (t10, c12-CLA) of the conjugated linoleic acid triglyceride is 1: 1.

Technical Field

The invention relates to preparation of conjugated linoleic acid triglyceride, in particular to a preparation method of high-quality and high-purity conjugated linoleic acid triglyceride.

Background

In the prior art, natural vegetable oil rich in linoleic acid is mainly adopted to prepare the conjugated linoleic acid, for example, the safflower oil is prepared into the conjugated linoleic acid by an alkali catalytic isomerization method, or the safflower oil is isomerized after alcoholysis and hydrolyzed to obtain the conjugated linoleic acid, the conjugated linoleic acid is lost in the purification process by the two methods, and the purity of the conjugated linoleic acid is reduced.

Chinese patent application CN107216249A discloses a method for preparing high-quality conjugated linoleic acid, which uses fatty acid short-chain alcohol ester as raw material to prepare conjugated linoleic acid through base-catalyzed isomerization reaction and saponification reaction. Although this solution solves the problem of the strong dependence of the conjugated linoleic acid content on the raw material, it must involve a base-catalyzed translocation step followed by purification, a process which entails loss of conjugated linoleic acid. Therefore, there is a need in the art for a method for preparing high-quality and high-purity conjugated linoleic acid.

Disclosure of Invention

In order to make up the defects of the prior art, the invention provides a high-content conjugated linoleic acid triglyceride and a preparation method thereof. The method has simple process and low cost, and can purify the conjugated linoleic acid triglyceride to more than 95%.

The invention adopts the following technical scheme that a preparation method of high-content conjugated linoleic acid triglyceride specifically comprises the following steps:

s1, crystallization and purification

Placing safflower oil methyl ester at-16-4 deg.C, maintaining for more than 10 hr, and filtering at low temperature to separate crystal and filtrate. Preferably, the safflower oil methyl ester is purified by subjecting to a low temperature of 2 ℃.

S2, rectification and purification

The bottom of the rectifying tower is connected with a thin film evaporator, the height of the tower is more than 1m, and the number of theoretical plates is not less than 30. Controlling the temperature of the thin film evaporator to be more than 200 ℃, keeping vacuum stability for 30min after reflux appears at the tower top, starting a condenser at the tower top, setting the reflux ratio to be at least 3:1, and collecting fractions to obtain purified safflower oil methyl ester.

S3. conjugation reaction

Under the vacuum condition, adding a potassium methoxide methanol solution with the mass of 10 percent of that of the safflower oil methyl ester dropwise into the purified safflower oil methyl ester, heating to 105-110 ℃ for conjugation reaction to obtain conjugated linoleic acid methyl ester;

more specifically, the conjugation reaction step is: under vacuum, a 10% methanol solution of potassium methoxide based on the weight of safflower oil methyl ester was added dropwise to the purified safflower oil methyl ester. The temperature is raised to 105-110 ℃. And after the reaction is qualified, cooling to 80 ℃, adding methanol, cooling to 45 ℃, adjusting the pH to 7-8 by using a methanol sulfate solution, adding sodium bisulfate accounting for 2% of the weight of the safflower oil methyl ester, starting steam, heating and refluxing, controlling the steam pressure to be less than 2.0MPa and the reflux temperature to be 65-75 ℃, continuously reacting for 1h, and removing the catalyst sodium bisulfate to obtain the conjugated methyl linoleate. The judgment standard of qualified reaction is as follows: and when the residual amount of the linoleic acid is less than or equal to 1.5 percent, judging that the reaction is qualified.

S4, esterification reaction

Adding glycerol triacetate with the mass of 0.18-0.25 times (preferably 0.22 times) of safflower oil methyl ester into conjugated linoleic acid methyl ester, mixing, vacuumizing, controlling nitrogen flow, and stabilizing at 15-20m³H, heating to 90 ℃. Dropwise adding sodium methoxide methanol solution with the mass of 2.5-4.0% (preferably 3.0%) of safflower oil methyl ester at a small flow rate, controlling the adding time to be finished for 30min, heating to 130-135 ℃, and carrying out heat preservation reaction for 7-10 h. After the reaction is finished, the nitrogen is broken. Cooling to 45 ℃, adding water in an amount which is 1 time of the weight of the safflower oil methyl ester into the kettle for washing until the Ph of a water layer is 6-7, heating to 80 ℃, and removing water.

S5, collecting

Starting a heat transfer oil system, controlling the temperature of the reaction kettle at 175-.

In the step S3, the method for removing the catalyst sodium bisulfate specifically comprises: and (3) evaporating methanol at normal pressure, simultaneously replenishing methanol into the kettle, heating until reflux appears in the kettle, and continuing to react for 1 hour. Adding water 0.3 times the weight of safflower oil methyl ester into the kettle, stirring for 20 minutes, and standing to remove acid water layer. Adding water 0.2 times the weight of safflower oil methyl ester into the kettle, and stirring for 20 minutes until the Ph of the water layer is 6-7. Stirring, heating to 100 deg.C, and removing water under reduced pressure.

Another object of the present invention is to claim the conjugated linoleic acid triglyceride obtained by the above process, wherein the ratio of the two isomers (c9, t11-CLA) to (t10, c12-CLA) is maintained at 1: 1.

The content of linoleic acid in safflower oil methyl ester is about 80%, but the safflower oil methyl ester contains fatty acids such as palmitic acid, stearic acid, oleic acid and the like in addition to linoleic acid, therefore, the direct preparation of linoleic acid with a certain purity by taking safflower oil methyl ester as a raw material increases the consumption of the raw material and improves the production cost, in addition, in the traditional process, the proportion of the safflower oil methyl ester isomer meeting the production requirements is difficult to maintain, the invention skillfully adjusts the process sequence, the linoleic acid content is increased to more than 95 percent by a crystallization purification method before the isomerization of the safflower oil methyl ester, then high-purity and high-content conjugated linoleic acid triglyceride is obtained by esterification reaction, the method can obviously improve the loss of the conjugated linoleic acid caused by purification after isomerization in the traditional process, not only saves the isomerization cost, but also more importantly improves the quality of the conjugated linoleic acid triglyceride.

Has the advantages that: the method has simple process, does not need the step of alkali-catalyzed transposition, and can greatly reduce the loss of the conjugated linoleic acid in the purification process and reduce the cost compared with the traditional process; in addition, the linoleic acid is purified and then conjugated, so that the proportion of two isomers (c9, t11-CLA) and (t10, c12-CLA) of the conjugated linoleic acid triglyceride can be kept at 1:1, and the purification method adopts a method of crystallization purification and high vacuum rectification, so that the linoleic acid is purified to more than 95 percent, has good application prospect and is suitable for large-scale application.

Drawings

FIG. 1 is a liquid phase spectrum of the product of example 1.

Detailed Description

The invention is described in more detail below with reference to specific examples, without limiting the scope of the invention. Unless otherwise specified, the experimental methods adopted by the invention are all conventional methods, and experimental equipment, materials, reagents and the like used in the experimental method can be obtained from commercial sources.