Process for preparing tyrosol laurate, catalyst for the preparation and process for preparing the catalyst

Abstract

The application discloses a preparation method of tyrosol laurate, a catalyst for preparation and a preparation method of the catalyst, and relates to the technical field of chemical synthesis, in particular to a preparation method of tyrosol laurate, which is prepared from tyrosol and lauric acid by using an imidazole ionic liquid 1-butyl-3-methyl imidazole hydrogen sulfate ([Bmim]HSO4) as a catalyst through an esterification reaction. The application can reduce the solvent cost in the preparation of tyrosol laurate, reduce the reaction system and facilitate product separation.

Description

Technical Field

[0001] This invention relates to the field of lipid antioxidant synthesis technology, specifically to a method for preparing tyrosol laurate, a catalyst for preparation, and a method for preparing the catalyst. Background Technology

[0002] Tyrosol is a natural phenolic compound found in plants such as Rhodiola rosea, privet, and olive. Due to its physiological activities including anticancer, anti-inflammatory, antidepressant, antiviral, antifatigue, anti-allergic, and antioxidant properties, it is used in pharmaceuticals, food, cosmetics, and agriculture. However, tyrosol's hydrophilicity and instability in vivo limit its bioavailability and application in lipid-rich foods. Tyrosol laurate is a lipophilic phenolic derivative that retains the biological activity of tyrosol while exhibiting improved lipophilicity. Being amphiphilic, tyrosol laurate can be used in lipid and oil-in-water emulsion systems. Due to the introduction of fatty acids, the highly lipophilic tyrosol laurate shows several advantages, including enhanced protection against oxidation in lipid-containing food matrices and improved pharmacological effects. Studies have shown that tyrosol laurate possesses good DPPH and ABTS free radical scavenging capabilities. Therefore, it can be used as an antioxidant in multiple fields. For example, tyrosol laurate can serve as a good antioxidant surfactant in emulsion systems, primarily acting at the oil-water interface to effectively inhibit emulsion oxidation. Furthermore, compared to tyrosol, tyrosol laurate exhibits stronger activity against trypanosomes and leishmaniasis. Therefore, it is essential to find a highly efficient, environmentally friendly, and green catalyst for the industrial preparation of tyrosol laurate.

[0003] The synthesis of tyrosol laurate is typically achieved through esterification. Due to considerations of activity and cost, it often relies on the traditional protic acid, p-toluenesulfonic acid. An acidic catalyst can form protons in the reaction system, ionizing the hydroxyl groups in the reactants and promoting the esterification reaction. P-toluenesulfonic acid has high acidity and can effectively catalyze the esterification reaction of tyrosol and laurate to prepare tyrosol laurate. However, this catalyst suffers from problems such as high acid strength and large dosage, severe equipment corrosion, generation of large amounts of waste acid polluting the environment, and difficulties in separation and recovery. Alternatively, it can be prepared under nitrogen protection, using anhydrous tetrahydrofuran as a co-solvent for tyrosol and TPP and DIAD as condensing agents, reacting for 48 hours. However, this method is more complex, the polarity of the generated byproducts is close to that of the target compound, and purification and separation of the product using silica gel column chromatography is difficult.

[0004] To further address the various problems existing in the aforementioned chemical methods, researchers have conducted extensive studies on the enzymatic catalytic preparation of tyrosol laurate. Enzymes, as catalysts for esterification reactions, can catalyze esterification or transesterification reactions under mild conditions, offering advantages such as high efficiency, high selectivity, and environmental friendliness. For example, Aissa et al. used an enzymatic catalytic esterification reaction to prepare tyrosol laurate, employing Novozym 435 as a catalyst and a tert-butanol / n-hexane mixed solvent, reacting for 72 hours, achieving a final yield of 73.33% for tyrosol laurate. Besides the one-step esterification method, methyl laurate can also be used as a raw material. Mateos et al. used tetrahydrofuran as a solvent and Novozym 435 to catalyze a transesterification reaction at 55°C to prepare tyrosol laurate, achieving a yield of 66%. Currently, Novozym 435 is commonly used to prepare tyrosol laurate; the enzyme is easily removed after the reaction, and the product tyrosol laurate can be obtained by column chromatography. However, the enzymatic synthesis of tyrosol laurate has a long reaction time (>24h), high cost ($2,500 / kg), and low yield (<75%).

[0005] Meanwhile, for the synthesis of tyrosol laurate, since both tyrosol and lauric acid are solid at room temperature and pressure, a solvent is required to promote the reaction, regardless of whether acid or enzymatic catalysis is used. This not only increases the preparation cost, but the larger reaction system due to the increased solvent content also leads to a decrease in the yield of tyrosol laurate to some extent. Furthermore, the solvent needs to be removed during the purification of tyrosol laurate, but it often cannot be removed along with the catalyst and unreacted substrate, further reducing the yield of tyrosol laurate due to multiple separation and purification processes of the crude product. Summary of the Invention

[0006] The present invention aims to provide a method for preparing tyrosol laurate, a catalyst for preparation, and a method for preparing the catalyst, thereby reducing solvent costs, reducing the reaction system size, and facilitating product separation in the preparation of tyrosol laurate.

[0007] To solve the above technical problems, the specific solution adopted in this invention is as follows: a method for preparing tyrosol laurate, using tyrosol and lauric acid as raw materials, and 1-butyl-3-methylimidazolium hydrogen sulfate, an imidazole ionic liquid, as a catalyst to prepare tyrosol laurate through an esterification reaction.

[0008] Preferably, tyrosol, lauric acid and imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate are mixed and then subjected to esterification reaction. After the esterification reaction is completed, the ionic liquid is separated to obtain crude product, and then the crude product is purified to obtain tyrosol laurate.

[0009] Preferably, it includes the following steps:

[0010] 1) Mix tyrosol, lauric acid, and imidazole-based ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate and carry out the esterification reaction under nitrogen protection;

[0011] 2) After the esterification reaction is completed, the system is cooled to room temperature, and the imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate is separated to obtain the crude product;

[0012] 3) The crude product obtained in step 2) is purified by saponification to obtain tyrosol laurate.

[0013] Preferably, the molar ratio of tyrosol to lauric acid in step 1) is 1:1-9.

[0014] Preferably, in step 1), the amount of 1-butyl-3-methylimidazolium hydrogen sulfate, an imidazole ionic liquid, added is 5-15% of the total mass of the raw materials.

[0015] Preferably, the reaction conditions for the esterification reaction in step 1) are: reaction temperature 105-130℃, reaction time 9-15h.

[0016] Preferably, in step 2), the imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate is separated by elution with diethyl ether.

[0017] Preferably, the saponification method in step 3) is sodium carbonate saponification, filtration, n-hexane extraction, and rotary evaporation.

[0018] A catalyst for the esterification preparation of tyrosol laurate, wherein the catalyst is an imidazole ionic liquid, 1-butyl-3-methylimidazolium hydrogen sulfate.

[0019] A method for preparing a catalyst for the esterification of tyrosol laurate includes the following steps:

[0020] 1) Dissolve 1-butyl-3-methylimidazolium bromide and sodium bisulfate in a solvent to obtain a mixture;

[0021] 2) The mixture obtained in step 1) is heated to react and a pretreated product is obtained;

[0022] 3) The pretreated material obtained in step 2) is subjected to rotary evaporation, washing and drying to obtain a catalyst for the esterification preparation of tyrosol laurate. Beneficial effects

[0023] This invention proposes a novel method for synthesizing tyrosol laurate using 1-butyl-3-methylimidazolium hydrogen sulfate, an imidazolium-based ionic liquid, as a catalyst-solvent. Since both the reaction substrates tyrosol and lauric acid are soluble in 1-butyl-3-methylimidazolium hydrogen sulfate, this ionic liquid catalyst functions as both a catalyst and solvent, eliminating the need for additional catalysts and thus saving on solvent input costs in the production of tyrosol laurate.

[0024] Furthermore, the catalytic preparation of tyrosol laurate from tyrosol and lauric acid in a solvent-free system allows for a smaller homogeneous reaction, enabling sufficient contact between the reactants and catalyst. This allows for more efficient utilization of 1-butyl-3-methylimidazolium hydrogen sulfate. The acidity of the catalyst provides [H]+ active sites for the esterification system, which helps the reactants and catalyst to come into full contact, thereby accelerating the reaction and increasing the yield of tyrosol laurate.

[0025] Finally, after the esterification reaction, since the product contains no solvent, the loss of tyrosol laurate due to solvent removal is eliminated, further improving the yield of tyrosol laurate. In a preferred embodiment of the invention, the ionic liquid catalyst can be eluted using diethyl ether, and the purification of tyrosol laurate only requires simple steps such as saponification, extraction, and rotary evaporation. This can be achieved using extraction flasks, funnels, etc., making the process simple and easy to implement.

[0026] In summary, compared with commonly used inorganic acid catalysis and enzymatic catalysis for the preparation of tyrosol laurate, the ionic liquid catalyst provided by this invention requires a shorter reaction time (<15h) and a higher yield of tyrosol laurate (>90%) due to the absence of solvent addition. Furthermore, the absence of solvent reduces preparation costs and simplifies the purification process of tyrosol laurate. Attached Figure Description

[0027] Figure 1 Synthetic route for the ionic liquid catalyst [Bmim]HSO4.

[0028] Figure 2 The infrared spectra of the ionic liquid synthesis precursor [Bmim]Br, sodium bisulfate, and catalyst [Bmim]HSO4 in Example 14 of this invention are shown.

[0029] Figure 3 Thermogravimetric curve of the ionic liquid catalyst [Bmim]HSO4 prepared in this invention.

[0030] Figure 4 The tyrosol laurate prepared in Example 14 of this invention 1 H NMR spectrum.

[0031] Figure 5The tyrosol laurate prepared in Example 14 of this invention 13 C NMR spectrum.

[0032] Figure 6 The graph shows the yield of tyrosol laurate and the yield of ionic liquid after multiple cycles of the catalyst [Bmim]HSO4 used in this invention.

[0033] Figure 7 The reaction pathway diagram for the preparation of tyrosol laurate by esterification catalyzed by the ionic liquid catalyst [Bmim]HSO4. Detailed Implementation

[0034] This invention discloses a method for preparing tyrosol laurate, using tyrosol and lauric acid as raw materials and an imidazole ionic liquid [Bmim]HSO4 as a catalyst, to prepare tyrosol laurate via an esterification reaction. The imidazole ionic liquid [Bmim]HSO4 is 1-butyl-3-methylimidazolium hydrogen sulfate, with the following structural formula:

[0035]

[0036] The preparation of tyrosol laurate specifically includes the following steps:

[0037] 1) Mix tyrosol, lauric acid, and imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate and protect with nitrogen; carry out esterification reaction under nitrogen protection; wherein the molar ratio of tyrosol to lauric acid is 1:1-9, the amount of imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate added is 5-15% of the total mass of raw materials, and the reaction conditions for esterification reaction are: reaction temperature 105-130℃, reaction time 9-15h.

[0038] 2) After the esterification reaction is completed, the system is cooled to room temperature, and the crude product is obtained by elution with diethyl ether to separate the imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate.

[0039] 3) The crude product obtained in step 2) was purified by saponification to obtain tyrosol laurate. The saponification method consisted of sodium carbonate saponification, filtration, hexane extraction, and rotary evaporation. Specifically, the mixture was washed multiple times with ether to remove the ionic liquid. After rotary evaporation at 30°C to obtain the crude product, the crude product (1g) was refluxed with a mixture of excess sodium carbonate, 95% ethanol (15ml), and water (5ml) for 20 minutes (45°C) under nitrogen protection for saponification. Excess sodium carbonate was removed by filtration. Then, it was extracted three times with hexane (20ml), and the hexane was removed by rotary evaporation (40°C). Finally, the product was lyophilized to obtain tyrosol laurate.

[0040] The preparation method of the above-mentioned imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate catalyst is as follows:

[0041] Accurately weigh 10.95 g (0.05 mol) of [Bmim]Br and 7.2 g (0.06 mol) of NaHSO4 into a 100 mL round-bottom flask. Add 30 mL of methanol as solvent and stir at 60 °C for 24 h. Filter to remove unreacted NaHSO4 and the generated bromide salt, then remove the solvent methanol by rotary evaporation (50 °C). Wash with ethyl acetate to remove unreacted [Bmim]Br, repeating several times until clean. Finally, remove ethyl acetate by rotary evaporation and dry under vacuum at 70 °C to obtain a yellow viscous liquid, [Bmim]HSO4.

[0042] The following method is used to recover and reuse the above-mentioned imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate catalyst in the production of tyrosol laurate:

[0043] Step 1): After the reaction is complete, add diethyl ether to wash away the ionized liquid catalyst [Bmim]HSO4, repeating several times until completely clean.

[0044] Step 2: The recovered catalyst [Bmim]HSO4 is rotary evaporated and vacuum dried before being used in the next esterification reaction.

[0045] This invention provides an ionic liquid catalyst, [Bmim]HSO4, for the catalytic reaction of tyrosol and lauric acid. [Bmim]HSO4 first reacts with the carbonyl group of lauric acid to enhance the positive charge of the carbonyl carbon, followed by an anionic attack of [Bmim]HSO4 to form a tetrahedral intermediate. Then, the nucleophile tyrosol undergoes a nucleophilic substitution reaction with this tetrahedral intermediate, decomposing to form the product tyrosol laurate. Simultaneously, the ionic liquid [Bmim]HSO4 is released back into the atmosphere. This results in the efficient synthesis of tyrosol laurate and enables the reuse of the ionic liquid. In some examples, the yield of tyrosol laurate remained above 88% even after the catalyst was reused up to seven times.

[0046] The following 25 examples illustrate the preparation method of tyrosol laurate of the present invention. In the examples of the present invention, high performance liquid chromatography equipped with an ultraviolet detector was used to analyze the reaction products. The chromatographic column used was a Symmetry C18 column (5μm, 250×4.6nm). The internal standard method was used to detect the product at an absorption wavelength of 224nm, and the yield of tyrosol laurate was calculated.

[0047] Example 1

[0048] 0.4145 g (3 mmol) of tyrosol, 0.6010 g (3 mmol) of lauric acid, and 0.1016 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 130 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 66.84%.

[0049] Example 2

[0050] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.3419 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 91.20%.

[0051] Example 3

[0052] 0.4145 g (3 mmol) of tyrosol, 5.4086 g (27 mmol) of lauric acid, and 0.2912 g of catalyst [Bmim]HSO4 (5% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 90.02%.

[0053] Example 4

[0054] 0.4145 g (3 mmol) of tyrosol, 5.4086 g (27 mmol) of lauric acid, and 0.5823 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 110 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 88.67%.

[0055] Example 5

[0056] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.1710 g of catalyst [Bmim]HSO4 (5% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 15 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 88.49%.

[0057] Example 6

[0058] 0.4145 g (3 mmol) of tyrosol, 0.6010 g (3 mmol) of lauric acid, and 0.1523 g of catalyst [Bmim]HSO4 (15% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 63.38%.

[0059] Example 7

[0060] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.5129 g of catalyst [Bmim]HSO4 (15% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 9 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 85.09%.

[0061] Example 8

[0062] 0.4145 g (3 mmol) of tyrosol, 5.4086 g (27 mmol) of lauric acid, and 0.5823 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 9 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 89.93%.

[0063] Example 9

[0064] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.5129 g of catalyst [Bmim]HSO4 (15% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 110 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 85.59%.

[0065] Example 10

[0066] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.3419 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 130 °C and esterified for 9 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 88.49%.

[0067] Example 11

[0068] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.1710 g of catalyst [Bmim]HSO4 (5% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 130 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 91.80%.

[0069] Example 12

[0070] 0.4145 g (3 mmol) of tyrosol, 5.4086 g (27 mmol) of lauric acid, and 0.5823 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 130 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 95.06%.

[0071] Example 13

[0072] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.3419 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 130 °C and esterified for 15 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 93.09%.

[0073] Example 14

[0074] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.3419 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 93.04%.

[0075] Example 15

[0076] 0.4145 g (3 mmol) of tyrosol, 0.6010 g (3 mmol) of lauric acid, and 0.1016 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 110 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 59.48%.

[0077] Example 16

[0078] 0.4145 g (3 mmol) of tyrosol, 0.6010 g (3 mmol) of lauric acid, and 0.0508 g of catalyst [Bmim]HSO4 (5% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 59.99%.

[0079] Example 17

[0080] 0.4145 g (3 mmol) of tyrosol, 0.6010 g (3 mmol) of lauric acid, and 0.1016 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 9 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 59.17%.

[0081] Example 18

[0082] 0.4145 g (3 mmol) of tyrosol, 5.4086 g (27 mmol) of lauric acid, and 0.5823 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 15 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 93.53%.

[0083] Example 19

[0084] 0.4145 g (3 mmol) of tyrosol, 5.4086 g (27 mmol) of lauric acid, and 0.8735 g of catalyst [Bmim]HSO4 (15% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 95.10%.

[0085] Example 20

[0086] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.5129 g of catalyst [Bmim]HSO4 (15% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 130 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 93.05%.

[0087] Example 21

[0088] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.5129 g of catalyst [Bmim]HSO4 (15% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 15 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 93.84%.

[0089] Example 22

[0090] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.3419 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 110 °C and esterified for 9 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 68.19%.

[0091] Example 23

[0092] 0.4145 g (3 mmol) of tyrosol, 0.6010 g (3 mmol) of lauric acid, and 0.1016 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 120 °C and esterified for 15 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 66.93%.

[0093] Example 24

[0094] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.3419 g of catalyst [Bmim]HSO4 (10% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 110 °C and esterified for 15 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 86.45%.

[0095] Example 25

[0096] 0.4145 g (3 mmol) of tyrosol, 3.0048 g (15 mmol) of lauric acid, and 0.1710 g of catalyst [Bmim]HSO4 (5% of the total reactants) were added to a two-necked flask. Under nitrogen protection, the mixture was heated to 110 °C and esterified for 12 h with magnetic stirring at 500 rpm. After the reaction, the system was cooled to room temperature using cooling water, and samples were taken. The yield of tyrosol laurate was determined by high-performance liquid chromatography (HPLC). The remaining mixture was washed with diethyl ether to remove the ionic liquid catalyst [Bmim]HSO4, and then subjected to rotary evaporation and saponification to obtain the product tyrosol laurate. The final yield of tyrosol laurate was 69.41%.

Claims

1. A method for preparing tyrosol laurate, characterized in that: Tyrosol laurate was prepared by esterification reaction using tyrosol and lauric acid as raw materials and imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate as catalyst. Tyrosol, lauric acid and imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate were mixed and subjected to esterification reaction. After the esterification reaction was completed, the ionic liquid was separated to obtain crude product, and then the crude product was purified to obtain tyrosol laurate. Includes the following steps: 1) Mix tyrosol, lauric acid, and imidazole-based ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate and carry out the esterification reaction under nitrogen protection. 2) After the esterification reaction is completed, the system is cooled to room temperature, and the imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate is separated to obtain the crude product; the imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate is separated by elution with diethyl ether. 3) The crude product obtained in step 2) is purified by saponification to obtain tyrosol lauryl ester; In step 1), the molar ratio of tyrosol to lauric acid is 1:1-9; In step 1), the amount of imidazole ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate added is 5-15% of the total mass of the raw materials; The reaction conditions for the esterification reaction in step 1) are: reaction temperature 105-130℃, reaction time 9-15h.

2. The method for preparing tyrosol laurate as described in claim 1, characterized in that: The saponification process in step 3) involves sodium carbonate saponification, filtration, hexane extraction, and rotary evaporation.

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