A method for purifying medium / long chain triglycerides

Abstract

The application provides a purification method of medium / long carbon chain triglyceride, and relates to the technical field of chemical engineering.The ion liquid is mixed with a polar diluent to obtain an extractant; the ion liquid comprises an anionic surface active ion liquid, a cationic surface active ion liquid or an anion-cation surface active ion liquid; the medium / long carbon chain triglyceride raw material is dissolved in a weakly polar organic solvent to obtain a raw material liquid; the raw material liquid is subjected to liquid-liquid extraction by using the extractant to obtain a raffinate phase, and the raffinate phase is subjected to distillation, and the residue is the medium / long carbon chain triglyceride; the liquid-liquid extraction comprises cross-flow extraction, countercurrent extraction or fractional distillation extraction.The purification method provided by the application has the advantages of simple process, simple operation, low cost, large processing capacity, high purification efficiency, high purity and high yield of the medium / long carbon chain triglyceride.

Description

Technical Field

[0001] This invention relates to the field of chemical engineering technology, and specifically to a method for purifying medium / long chain triglycerides. Background Technology

[0002] Triglycerides are glycerol esters formed by the esterification of all three hydroxyl groups of glycerol with fatty acids. Based on alkyl chain length, triglycerides can be classified into short-chain (C2-C5), medium-chain (C6-C12), and long-chain (C13-C24) triglycerides. Medium-chain triglycerides can be completely absorbed into the small intestinal mucosa and enter cells without bile salts, and directly enter the liver via the portal vein as fatty acids. They provide rapid energy without accumulating as fat, thus offering significant health benefits. Clinically, they are mainly used for weight loss, promoting energy metabolism, and aiding in the recovery of individuals with dementia. Furthermore, triglycerides are a major component of dietary fat and one of the primary forms of energy acquisition and storage for animals and humans. They are also important raw materials in the chemical and pharmaceutical industries. Structured triglycerides are a key raw material for the production of next-generation fat emulsions—structured fat emulsion injections (C6-24).

[0003] Triglycerides, including structural triglycerides, are prepared through chemical synthesis and enzymatic methods. During preparation, byproducts such as fatty acids, monoglycerides, and diesters are inevitably generated, requiring separation and purification to obtain high-purity triglycerides. Currently, triglyceride purification methods mainly include molecular distillation, chromatography, simulated moving bed chromatography, bio-enzymatic hydrolysis, and combined methods (e.g., silica gel adsorption / silica gel column adsorption-membrane / molecular distillation combined methods, bio-enzymatic catalysis). Molecular distillation suffers from high distillation temperatures and stringent equipment costs and parameter requirements. Chromatography separates triglycerides based on differences in product polarity, but is limited by silica gel column packing size and consumes large amounts of organic solvents, making it unsuitable for industrial applications of triglyceride purification. Simulated moving bed chromatography yields near-100% purity triglyceride monomers, but the equipment is complex and has high investment costs. Silica gel adsorption / silica gel column adsorption-membrane / molecular distillation combined methods provide high-purity triglycerides, but are cumbersome and have low throughput. The method involves using bio-enzymatic hydrolysis to convert non-triglyceride components of the raw material into non-triglyceride components, followed by removal of the aqueous phase to obtain triglycerides. This method yields high-purity triglycerides, but is relatively expensive and complex. Therefore, researching simple, low-cost, and scalable purification methods for medium / long-chain triglycerides has significant application value. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a purification method for medium / long chain triglycerides. The purification method provided by this invention is simple, low-cost, has a large throughput, high purification efficiency, and yields medium / long chain triglyceride products with high purity and high yield.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for purifying medium / long chain triglycerides, comprising the following steps:

[0007] An extractant is obtained by mixing an ionic liquid with a polar diluent; the ionic liquid includes anionic surfactants, cationic surfactants, or anionic and cationic surfactants.

[0008] Medium / long chain triglyceride raw materials are dissolved in a weakly polar organic solvent to obtain a raw material solution;

[0009] The feed liquid is subjected to liquid-liquid extraction using the extractant to obtain a raffinate phase, which is then distilled to obtain a medium / long chain triglyceride residue. The liquid-liquid extraction includes cross-current extraction, countercurrent extraction, or fractional distillation extraction.

[0010] Preferably, the anionic surfactant liquid comprises short-chain cations and long-chain anions;

[0011] The short-chain cation is a cation containing a short-chain substituent, including imidazole cation, piperidine cation, pyridine cation, quaternary phosphorus cation, quaternary ammonium cation, amino acid cation, or choline cation; the short-chain substituent includes alkyl, olefinic, or hydroxylated alkyl groups, and the short-chain substituent has ≤4 carbon atoms;

[0012] The long-chain anion is an anion containing a long-chain substituent, including carboxylic acid anion, amino acid anion, phosphate anion, sulfonic acid anion, or sulfate anion; the long-chain substituent has ≥6 carbon atoms.

[0013] Preferably, the cationic surfactant liquid comprises long-chain cations and anions;

[0014] The long-chain cation is a cation containing a long-chain substituent, including imidazole cation, piperidine cation, pyridine cation, quaternary phosphorus cation, or quaternary ammonium cation; the long-chain substituent has ≥6 carbon atoms;

[0015] The anions include halide ions, perchlorate ions, nitrate ions, bisulfate ions, dihydrogen phosphate ions, carboxylic acid anions containing short-chain substituents, or amino acid anions containing short-chain substituents; the short-chain substituents in the carboxylic acid anions and amino acid anions containing short-chain substituents independently include alkyl, olefinic, or hydroxylated alkyl groups, and the number of carbon atoms in the short-chain substituents is ≤4.

[0016] Preferably, the cationic and anionic surfactant liquids comprise long-chain cations and long-chain anions;

[0017] The long-chain cation is a cation containing a long-chain substituent, including imidazole cation, piperidine cation, pyridine cation, quaternary phosphorus cation, or quaternary ammonium cation; the long-chain substituent has ≥6 carbon atoms;

[0018] The long-chain anion is an anion containing a long-chain substituent, including carboxylic acid anion, amino acid anion, phosphate anion, sulfonic acid anion, or sulfate anion; the long-chain substituent has an independent carbon number of ≥6.

[0019] Preferably, the long carbon chain substituent has 6 to 24 carbon atoms.

[0020] Preferably, the molar fraction of the ionic liquid in the extractant is 0.1% to 90%;

[0021] The polar diluent includes one or more of acetonitrile, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and methanol.

[0022] Preferably, the purity of the medium / long chain triglyceride raw material is 20-90%;

[0023] The weakly polar organic solvent includes C6-C20 straight-chain saturated alkanes and / or branched-chain saturated alkanes;

[0024] The concentration of the raw material solution is 0.1–300 g / L.

[0025] Preferably, the process parameters of the cross-flow extraction include: 2 to 8 extraction stages, a flow ratio of extractant to feed liquid of 1:(0.05 to 20), and an extraction temperature of 10 to 50°C.

[0026] Preferably, the process parameters for the countercurrent extraction include: 2 to 8 extraction stages, a flow ratio of extractant to feed liquid of 1:(0.03 to 20), and an extraction temperature of 10 to 50°C.

[0027] Preferably, a detergent is also added during the fractionation extraction process, and the detergent includes a weakly polar organic solvent;

[0028] The process parameters for fractionation extraction include: the number of extraction stages is 1 to 20, the number of washing stages is 1 to 10, the flow ratio of extractant to feed liquid is 1:(0.05 to 20), and the flow ratio of extractant to washing agent is 1:(0.05 to 20).

[0029] This invention involves mixing an ionic liquid with a polar diluent to obtain an extractant. The ionic liquid includes anionic surfactants, cationic surfactants, or anionic-cationic surfactants. A medium / long-chain triglyceride raw material is dissolved in a weakly polar organic solvent to obtain a raw material solution. The raw material solution is then subjected to liquid-liquid extraction using the extractant to obtain a raffinate phase. This raffinate phase is then distilled, and the residue is a medium / long-chain triglyceride. The liquid-liquid extraction includes cross-current extraction, countercurrent extraction, or fractional distillation extraction. Ionic liquids generally refer to compounds composed of anions and cations that are liquid at or near room temperature. Compared to molecular solvents, the ionic liquids utilized in this invention have unique structures, giving them unique physicochemical properties such as low volatility, low melting point, high cohesive energy, and non-flammability. Furthermore, as designable solvents, the properties of ionic liquids can be adjusted by modifying the anion and cation structures. These characteristics allow ionic liquids to serve as environmentally friendly solvents to replace traditional volatile organic solvents in liquid-liquid extraction. This invention utilizes ionic liquids for liquid-liquid extraction of medium / long-chain triglyceride raw materials, offering advantages such as high throughput and simple operation. Furthermore, this invention, targeting the structural characteristics of medium / long-chain triglycerides and their impurities, employs an ionic liquid with demonstrable activity as the extractant. Based on the differences in the strength of hydrogen bonds and other interactions between the target and impurities and the ionic liquid, molecular recognition extraction and separation are achieved, yielding high-purity medium / long-chain triglycerides. The purification method provided by this invention is simple, low-cost, has a high throughput, high purification efficiency, and produces medium / long-chain triglyceride products with high purity and high yield. Attached Figure Description

[0030] Figure 1 The process flow diagrams are for cross-current extraction, countercurrent extraction, and fractional extraction.

[0031] Figure 2 The HPLC chromatogram of the octanoic acid triglyceride product prepared in Example 1 is shown below.

[0032] Figure 3 The HPLC spectrum of the undecanoic acid triglyceride product prepared in Example 2;

[0033] Figure 4 The HPLC chromatogram of the pentadecanoic acid triglyceride product prepared in Example 19 is shown. Detailed Implementation

[0034] This invention provides a method for purifying medium / long chain triglycerides, comprising the following steps:

[0035] An extractant is obtained by mixing an ionic liquid with a polar diluent; the ionic liquid includes anionic surfactants, cationic surfactants, or anionic and cationic surfactants.

[0036] Medium / long chain triglyceride raw materials are dissolved in a weakly polar organic solvent to obtain a raw material solution;

[0037] The feed liquid is subjected to liquid-liquid extraction using the extractant to obtain a raffinate phase. The raffinate phase is then distilled, and the residue is a medium / long chain triglyceride product. The liquid-liquid extraction includes cross-current extraction, countercurrent extraction, or fractional distillation extraction.

[0038] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0039] This invention involves mixing an ionic liquid with a polar diluent to obtain an extractant.

[0040] In this invention, the ionic liquid includes anionic surfactant ionic liquid, cationic surfactant ionic liquid, or anionic and cationic surfactant ionic liquid.

[0041] In this invention, the anionic surfactant liquid preferably comprises short-chain cations and long-chain anions. The short-chain cation is preferably a cation containing a short-chain substituent, and preferably includes imidazole cations, piperidine cations, pyridine cations, quaternary phosphonium cations, quaternary ammonium cations, amino acid cations, or choline cations; the short-chain substituent preferably includes alkyl, olefinic, or hydroxylated alkyl groups, and the number of carbon atoms in the short-chain substituent is preferably ≤4, although in specific embodiments the number of carbon atoms can be 1, 2, 3, or 4. In this invention, the long-chain anion is preferably an anion containing a long-chain substituent, and the anion preferably includes a carboxylic acid anion, an amino acid anion, a phosphate anion, a sulfonic acid anion, or a sulfate anion; the number of carbons of the long-chain substituent is preferably ≥6, more preferably 6 to 24, and even more preferably 8 to 18. In specific embodiments, the number of carbons can be 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24.

[0042] In this invention, the anionic surfactant preferably includes one or more of the following: choline long-chain fatty acid salt, 1-ethyl-3-methylimidazolium long-chain fatty acid salt, 1-hydroxyethyl-3-methylimidazolium long-chain fatty acid salt, tetraethyl quaternary phosphonium long-chain fatty acid salt, and tetraethyl quaternary ammonium long-chain fatty acid salt.

[0043] In this invention, the cationic surfactant preferably comprises long-chain cations and anions. The long-chain cation is preferably a cation containing long-chain substituents, and the cation preferably includes imidazole cations, piperidine cations, pyridine cations, quaternary phosphonium cations, or quaternary ammonium cations. The long-chain substituent preferably has ≥6 carbon atoms, more preferably 6–24, and even more preferably 8–18. In specific embodiments, the carbon number can be 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24. In this invention, the anion preferably includes halide ions, perchlorate ions, nitrate ions, hydrogen sulfate ions, dihydrogen phosphate ions, carboxylic acid anions containing short-chain substituents, or amino acid anions containing short-chain substituents; the short-chain substituents in the carboxylic acid anions and amino acid anions containing short-chain substituents preferably independently include alkyl, olefinic, or hydroxylated alkyl groups, and the number of carbon atoms in the short-chain substituents is preferably ≤4, but in specific embodiments the number of carbon atoms can be 1, 2, 3, or 4.

[0044] In this invention, the cationic surfactant preferably includes one or more of tetraethyl quaternary phosphonium dodecyl sulfonate, 1-vinyl-3-methylimidazolium dodecyl sulfonate, 1-dodecyl-3-methylimidazolium acetate, 1-dodecyl-3-methylimidazolium chloride, dodecyltrimethylammonium chloride, and dodecylpyridine chloride or 1-decyl-3-methylimidazolium hydrogen sulfate.

[0045] In this invention, the cationic and anionic surfactants preferably include long-chain cations and long-chain anions. The types of long-chain cations are the same as those of long-chain cations in the cationic surfactant, and the types of long-chain anions are the same as those of long-chain anions in the anionic surfactant. These will not be described in detail here.

[0046] In this invention, the anionic and cationic surfactant ionic liquids preferably include one or more of tetraoctyl quaternary phosphonium long-chain fatty acid salt, 1-octyl-3-methylimidazolium long-chain fatty acid salt, dodecyltrimethylammonium long-chain sulfonate, 1-octyl-3-methylimidazolium long-chain sulfate, and 1-octyl-3-methylimidazolium long-chain amino acid salt.

[0047] In this invention, the polar diluent preferably includes one or more of water, acetonitrile, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and methanol.

[0048] In this invention, the molar fraction of the ionic liquid in the extractant is preferably 0.1% to 90%, more preferably 0.5% to 50%. In specific embodiments of this invention, it can be 0.1%, 0.5%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%. In this invention, excessive addition of the ionic liquid will result in excessively high extractant viscosity, which is detrimental to mass transfer.

[0049] This invention dissolves medium / long chain triglyceride raw materials in a weakly polar organic solvent to obtain a raw material solution.

[0050] In this invention, the purity of the medium / long chain triglyceride raw material is preferably 20-90%, and in specific embodiments of this invention, it can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%. In this invention, the impurities in the medium / long chain triglyceride raw material preferably include one or more of medium / long chain fatty acids, medium / long chain monoglycerides, and medium / long chain diesters. In this invention, the medium / long chain triglycerides in the medium / long chain triglyceride raw materials preferably include medium chain triglycerides or long chain triglycerides; the number of carbon atoms in the medium / long chain of the medium / long chain triglycerides, medium / long chain fatty acids, medium / long chain monoglycerides and medium / long chain diesters is preferably 8 to 24, and in specific embodiments of this invention, it can be 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24.

[0051] In this invention, the weakly polar organic solvent preferably includes straight-chain saturated alkanes and / or branched-chain saturated alkanes of C6 to C20, and more preferably C6 to C12. In specific embodiments, C6 to C20 can be C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19 or C20.

[0052] In this invention, the concentration of the raw material solution is preferably 0.1–300 g / L, more preferably 20–200 g / L. In specific embodiments of this invention, it can be 0.1 g / L, 0.5 g / L, 1 g / L, 5 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L, 55 g / L, 60 g / L, 65 g / L, 70 g / L, 75 g / L, 80 g / L, 85 g / L, 90 g / L, 95 g / L, 100 g / L, 105 g / L, 110 g / L, 115 g / L, 120 g / L, 125 g / L, 130 g / L, 1 35g / L, 140g / L, 145g / L, 150g / L, 155g / L, 160g / L, 165g / L, 170g / L, 175g / L, 180g / L, 185g / L, 190g / L, 195g / L, 200g / L, 205g / L, 210g / L, 215g / L, 220g / L, 225g / L, 230g / L, 235g / L, 240g / L, 245g / L, 250g / L, 255g / L, 260 g / L, 265g / L, 270g / L, 275g / L, 280g / L, 285g / L, 290g / L, 295g / L or 300g / L.

[0053] After obtaining the extractant and the raw material liquid, the present invention uses the extractant to perform liquid-liquid extraction on the raw material liquid to obtain the raffinate phase, and then distills the raffinate phase to obtain the residue as medium / long chain triglycerides.

[0054] In this invention, the extraction liquid includes cross-current extraction, countercurrent extraction, or fractional distillation extraction. The process flow diagram for cross-current extraction in this invention is shown below. Figure 1 In this cross-current extraction process, fresh extractant is used in each stage, allowing for higher product purity within a lower number of stages. The process flow diagram for this counter-current extraction is shown below. Figure 1 In countercurrent extraction, the raw material and detergent enter from opposite ends of the extraction device. After thorough mixing and phase separation in each stage, the light and heavy phases enter the adjacent extraction stages respectively. This method is simple to operate. The process flow diagram of the fractionation extraction in this invention is shown below. Figure 1 Fractional extraction consists of an extraction section and a washing section. The feed liquid is injected between the extraction section and the washing section. This method can simultaneously obtain high purity and high recovery rate.

[0055] In this invention, the preferred process parameters for the cross-flow extraction include: 2 to 8 extraction stages, which in specific embodiments can be 2, 3, 4, 5, 6, 7, or 8 stages; and a flow ratio (rate ratio) of 1:(0.05 to 20), preferably 1:(0.1 to 10, which in specific embodiments can be 1:0.05, 1:0.1, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1: 8, 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.5, 1:12, 1:12.5, 1:13, 1:13.5, 1:14, 1:14.5, 1:15, 1:15.5, 1:16, 1:16.5, 1:17, 1:17.5, 1:18, 1:18.5, 1:19, 1:19.5, or 1:20; the extraction temperature is 10–50°C, preferably 20–35°C, and in specific embodiments of the present invention, it can be 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, or 50°C. The medium / long chain triglycerides obtained by the cross-flow extraction method of the present invention have high purity.

[0056] In this invention, the preferred process parameters for countercurrent extraction include: 2 to 8 extraction stages, which in specific embodiments can be 2, 3, 4, 5, 6, 7, or 8 stages; and a flow ratio of extractant to feed liquid of 1:(0.03 to 20), preferably 1:(0.1 to 10, which in specific embodiments can be 1:0.03, 1:0.04, 1:0.05, 1:0.1, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, or 1:7. 5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.5, 1:12, 1:12.5, 1:13, 1:13.5, 1:14, 1:14.5, 1:15, 1:15.5, 1:16, 1:16.5, 1:17, 1:17.5, 1:18, 1:18.5, 1:19, 1:19.5, or 1:20; the extraction temperature is 10–50°C, preferably 20–35°C, and in specific embodiments of the present invention, it can be 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, or 50°C.

[0057] In this invention, a detergent is preferably added during the fractionation extraction process. The detergent preferably includes a weakly polar organic solvent. The types of weakly polar organic solvents that can be selected are the same as those selected for the weakly polar organic solvents in the feed liquid, and will not be repeated here. In this invention, the process parameters for the fractionation extraction preferably include: the number of extraction stages is 1 to 20, preferably 2 to 8. In specific embodiments of this invention, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 5, 16, 17, 18, 19, or 20 stages; the number of washing stages is 1 to 10, preferably 2 to 4 stages. In specific embodiments of this invention, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 stages. The flow ratio of extractant to feed liquid is 1:(0.05-20), preferably 1:(0.1-10). In specific embodiments of the present invention, it can be 1:0.05, 1:0.1, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.5, 1:12, etc. The ratios of extractant to detergent are 1:12.5, 1:13, 1:13.5, 1:14, 1:14.5, 1:15, 1:15.5, 1:16, 1:16.5, 1:17, 1:17.5, 1:18, 1:18.5, 1:19, 1:19.5, or 1:20; the flow ratio of extractant to detergent is 1:(0.05~20), preferably 1:(0.1~10, and in specific embodiments of the present invention, it can be 1:0.05, 1:0.1, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, etc. The ratios are 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.5, 1:12, 1:12.5, 1:13, 1:13.5, 1:14, 1:14.5, 1:15, 1:15.5, 1:16, 1:16.5, 1:17, 1:17.5, 1:18, 1:18.5, 1:19, 1:19.5, or 1:20. The medium / long chain triglycerides obtained by fractional distillation extraction in this invention have high purity and high yield.

[0058] Prior to distillation, the present invention preferably includes water washing, and the resulting water washing residue is then subjected to further distillation. The medium / long chain triglyceride product obtained by distillation after water washing has higher purity. The present invention does not have any particular limitation on the distillation, as long as the solvent can be removed, such as vacuum distillation.

[0059] Ionic liquids generally refer to compounds composed of cations and anions that are liquid at or near room temperature. Compared to molecular solvents, the ionic liquids utilized in this invention possess unique structures, giving them distinctive physicochemical properties such as low volatility, low melting point, high cohesive energy, and non-flammability. Furthermore, as designable solvents, the properties of ionic liquids can be adjusted by modifying the structures of the cations and anions. These characteristics allow ionic liquids to serve as environmentally friendly alternatives to traditional volatile organic solvents in liquid-liquid extraction. This invention utilizes ionic liquids for liquid-liquid extraction of medium / long-chain triglyceride raw materials, offering advantages such as high throughput and simple operation. Moreover, this invention, targeting the structural characteristics of medium / long-chain triglycerides and their impurities, employs ionic liquids with apparent activity as extractants. Based on the differences in the strength of hydrogen bonds and other interactions between the target and impurities and the ionic liquid, molecular recognition extraction and separation are achieved, yielding high-purity medium / long-chain triglycerides. The purification method provided by this invention is simple, low-cost, has a high throughput, high purification efficiency, and produces medium / long-chain triglyceride products with high purity and high yield.

[0060] To further illustrate the present invention, the purification method for medium / long chain triglycerides provided by the present invention is described in detail below with reference to the embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0061] In the following examples, caprylic triglyceride is n-caprylic triglyceride, undecanoic triglyceride is n-undecanoic triglyceride, pentadecanoic triglyceride is n-pentadecanoic triglyceride, and teicocyanic triglyceride is n-teicocyanic triglyceride.

[0062] Example 1

[0063] Caprylic triglyceride feedstock (HPLC purity 62.1%) was dissolved in n-hexane to obtain a feedstock solution with a concentration of 50 g / L. Acetonitrile and choline laurate were mixed to obtain an extractant with a choline laurate concentration of 5 mol%. The feedstock solution was subjected to a four-stage cross-flow extraction using the extractant, with a flow ratio of extractant to feedstock of 0.5:1 in each stage, and an extraction temperature of 30℃. The raffinate was collected, washed with water, and then distilled under reduced pressure. The residue was the caprylic triglyceride product. The HPLC purity of the caprylic triglyceride product was 97.3%, and the yield was 80.4%. The HPLC chromatogram of the caprylic triglyceride product is shown below. Figure 2 As shown.

[0064] Example 2

[0065] Undecanoic acid triglyceride raw material (HPLC purity 73.0%) was dissolved in n-hexane to obtain a raw material solution with a concentration of 100 g / L. Choline laurate was mixed with DMSO to obtain an extractant with a choline laurate concentration of 10 mol%. The raw material solution was subjected to a four-stage cross-flow extraction at 30°C, with an extractant-to-raw material flow ratio of 1:1. The raffinate was washed with water and then distilled under reduced pressure to obtain the undecanoic acid triglyceride product. The HPLC purity of the undecanoic acid triglyceride product was 97.9%, and the yield was 74.0%. The HPLC chromatogram of the undecanoic acid triglyceride product is shown below. Figure 3 As shown.

[0066] Example 3

[0067] The only difference from Example 2 is that a two-stage cross-flow extraction was performed, and the HPLC purity of the undecanoic acid triglyceride product was 95.3%, with a yield of 83.2%.

[0068] Example 4

[0069] The only difference from Example 2 is that the ionic liquid cation is different; the ionic liquid is 1-butyl-3-methylimidazolium laurate, and the HPLC purity of the obtained undecanoic acid triglyceride product is 95.1%, with a yield of 76.9%.

[0070] Example 5

[0071] The only difference from Example 2 is the different anion of the ionic liquid. The ionic liquid is choline octanoate, and the HPLC purity of the obtained undecanoic acid triglyceride product is 94.4%, with a yield of 80.1%.

[0072] Example 6

[0073] The only difference from Example 2 is that the multi-stage extraction method is 4-stage countercurrent extraction, and the HPLC purity of the obtained undecanoic acid triglyceride product is 95.5%, with a yield of 86.2%.

[0074] Example 7

[0075] Undecanoic acid triglyceride raw material (HPLC purity 73.0%) was dissolved in n-hexane to obtain a raw material solution with a concentration of 100 g / L. Choline laurate was mixed with DMSO to obtain an extractant with a choline laurate concentration of 10 mol%. The raw material solution was fractionally extracted with the extractant at 30 °C. The washing agent was the same as the raw material solvent. The flow ratio of raw material solution, extractant, and washing agent was 0.8:1:0.2. The extraction stage and washing stage were 3 and 1 stages, respectively. The extraction temperature was 30 °C. The raffinate was washed with water and then distilled under reduced pressure to obtain undecanoic acid triglyceride. The HPLC purity of the undecanoic acid triglyceride product was 95.1%, and the yield was 90.4%.

[0076] Example 8

[0077] The only difference from Example 7 is that the number of multi-stage extraction stages is different. The extraction stage has 5 stages and the washing stage has 3 stages. The HPLC purity of the obtained undecanoic acid triglyceride product is 95.4% and the yield is 98.3%.

[0078] Example 9

[0079] The only difference from Example 7 is that the concentration of choline laurate in the extractant is 5 mol%, and the HPLC purity of the obtained undecanoic acid triglyceride product is 95.4%, with a yield of 96.5%.

[0080] Example 10

[0081] The only difference from Example 7 is that the concentration of choline laurate in the extractant is 50 mol%, and the HPLC purity of the obtained undecanoic acid triglyceride product is 99.4%, with a yield of 98.5%.

[0082] Example 11

[0083] The only difference from Example 7 is that the polar diluent in the extractant is NMP, and the HPLC purity of the obtained undecanoic acid triglyceride product is 98.6%, with a yield of 96.8%.

[0084] Example 12

[0085] The only difference from Example 7 is that the extraction temperature was 45°C, and the HPLC purity of the obtained undecanoic acid triglyceride product was 94.3%, with a yield of 96.4%.

[0086] Example 13

[0087] The only difference from Example 7 is that the concentration of the raw material solution is 20 g / L, and the HPLC purity of the obtained undecanoic acid triglyceride product is 95.3%, with a yield of 94.6%.

[0088] Example 14

[0089] The only difference from Example 7 is that the solvent in the raw material solution is n-decane, and the HPLC purity of the obtained undecanoic acid triglyceride product is 95.5%, with a yield of 94.8%.

[0090] Example 15

[0091] The only difference from Example 8 is that the HPLC purity of the undecanoic acid triglyceride raw material is 41.6%, the HPLC purity of the obtained undecanoic acid triglyceride product is 91.4%, and the yield is 97.6%.

[0092] Example 16

[0093] The only difference from Example 7 is that the ionic liquid is tetraethyl quaternary phosphonium dodecyl sulfonate, and the HPLC purity of the obtained undecanoic acid triglyceride product is 93.7%, with a yield of 98.1%.

[0094] Example 17

[0095] The only difference from Example 7 is that the ionic liquid is 1-octyl-3-methylimidazolium N-palmitoylalanine salt, and the HPLC purity of the obtained undecanoic acid triglyceride product is 95.2%, with a yield of 99.0%.

[0096] Example 18

[0097] The only difference from Example 7 is that the ionic liquid is 1-dodecyl-3-methylimidazolium chloride, and the HPLC purity of the obtained undecanoic acid triglyceride product is 96.7%, with a yield of 98.3%.

[0098] Example 19

[0099] The only difference from Example 7 is that the raw material was pentadecanoic acid triglyceride (HPLC purity 74.9%), and the obtained pentadecanoic acid triglyceride product had an HPLC purity of 95.7% and a yield of 94.1%. The HPLC chromatogram of the pentadecanoic acid triglyceride product is shown below. Figure 4 As shown.

[0100] Example 20

[0101] The only difference from Example 7 is that the raw material is caprylic triglyceride (HPLC purity of 69.2%), and the HPLC purity of the obtained caprylic triglyceride product is 95.9%, with a yield of 98.2%.

[0102] Example 21

[0103] The only difference from Example 12 is that the raw material is triglyceride cocoate (HPLC purity of 69.2%), and the HPLC purity of the obtained triglyceride cocoate product is 98.2%, with a yield of 97.3%.

[0104] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for purifying medium / long chain triglycerides, comprising the following steps: An extractant is obtained by mixing an ionic liquid with a polar diluent; the ionic liquid includes anionic surfactants, cationic surfactants, or anionic and cationic surfactants. Medium / long chain triglyceride raw materials are dissolved in a weakly polar organic solvent to obtain a raw material solution; the weakly polar organic solvent includes C6~C20 straight-chain saturated alkanes and / or branched-chain saturated alkanes. The feed liquid is subjected to liquid-liquid extraction using the extractant to obtain a raffinate phase, which is then distilled to obtain a medium / long chain triglyceride residue. The liquid-liquid extraction includes cross-current extraction, countercurrent extraction, or fractional distillation extraction. The anionic surfactant liquid comprises short-chain cations and long-chain anions; the short-chain cations are cations containing short-chain substituents, and the cations are imidazole cations, quaternary phosphonium cations, or choline cations; the long-chain anions are anions containing long-chain substituents, and the anions are carboxylic acid anions or sulfonic acid anions. The cationic surfactant liquid comprises long-chain cations and anions; the long-chain cations are cations containing long-chain substituents, the cations are imidazole cations, and the anions are halide ions; The long-chain substituents in the anionic and cationic surfactant ionic liquids have ≥6 carbons, the short-chain substituents have ≤4 carbons, and the substituents are alkyl groups. The anionic and cationic surfactant ionic liquid is 1-octyl-3-methylimidazolium N-palmitoylalanine salt; The polar diluent is one or more of acetonitrile, dimethyl sulfoxide, and N-methylpyrrolidone.

2. The purification method according to claim 1, characterized in that, The long carbon chain substituent has 6 to 24 carbon atoms.

3. The purification method according to claim 1, characterized in that, The molar fraction of ionic liquid in the extractant is 0.1-90%.

4. The purification method according to claim 1, characterized in that, The purity of the medium / long chain triglyceride raw material is 20-90%; The concentration of the raw material solution is 0.1~300g / L.

5. The purification method according to claim 1, characterized in that, The process parameters for the cross-flow extraction include: 2 to 8 extraction stages, a flow ratio of extractant to feed liquid of 1:(0.05 to 20), and an extraction temperature of 10 to 50°C.

6. The purification method according to claim 1, characterized in that, The process parameters for the countercurrent extraction include: 2 to 8 extraction stages, a flow ratio of extractant to feed liquid of 1:(0.03 to 20), and an extraction temperature of 10 to 50°C.

7. The purification method according to claim 1, characterized in that, A detergent is also added during the fractionation extraction process, and the detergent includes a weakly polar organic solvent; The process parameters for fractionation extraction include: the number of extraction stages is 1 to 20, the number of washing stages is 1 to 10, the flow ratio of extractant to feed liquid is 1:(0.05 to 20), and the flow ratio of extractant to washing liquid is 1:(0.05 to 20).

Images