A method for improving the yield of hydration reaction of myrcene or dihydromyrcene and synthetic fragrance

Abstract

The invention discloses a method for improving the yield of hydration reaction of myrcene or dihydromyrcene and a synthetic fragrance, belonging to the technical field of deep processing of forest chemical products. The method comprises steps of synthesis reaction, catalyst recovery, solvent recovery, product neutralization, product fractionation, etc. The invention adopts a composite catalyst composed of one or more of zirconium sulfate, titanium sulfate, α-hydroxy acid and divalent copper salt to catalyze the hydration reaction of myrcene or dihydromyrcene, thereby improving the yield of hydration products and reducing side reactions and energy consumption.

Description

Technical Field

[0001] The invention relates to the technical field of deep processing of forest chemical products, and in particular to a method for improving the hydration reaction yield of myrcene or dihydromyrcene and a synthetic fragrance. Background Art

[0002] Linalool is also known as linalool, coriander alcohol, galool, linalool, etc. Its scientific name is 3,7-dimethyl-1,6-octadiene-3-ol, with a molecular formula of C10H180 and a molecular weight of 154.24. The main methods for synthesizing linalool are: first, β-pinene is cracked into myrcene at high temperature, and then linalool is made through hydrochloric acid, esterification, saponification and other steps. Other alcohols produced by this method include nerol, geraniol, lauryl alcohol and pinene alcohol. This method has a relatively high yield. Second, α-pinene is hydrogenated to pinane, then oxidized to pinane hydroperoxide, and then reduced to pinane alcohol, and finally pyrolyzed to produce linalool. Dihydromyrcenol is obtained by chlorinating dihydromyrcene and then hydrolyzing it in alkaline water. It can also be obtained by first esterifying dihydromyrcene with acetic acid or formic acid, and then saponifying and hydrolyzing it in alkaline. It is a liquid with lemon and lavender aromas. Dihydromyrcenol has fresh floral and white lemon-like fruity aromas and can be used in daily chemical fragrance formulas, especially suitable for soap fragrances (formula content can reach 20%). It is a representative of "excessive use" in modern men's perfumes and fragrances, with an output of about 5,000 tons.

[0003] Chinese patent application CN200810106990.1 discloses a method for synthesizing dihydromyrcenol from dihydromyrcene using a niobic acid catalyst. Chinese patent application CN201010249029.5 discloses a method for using cation exchange resins including Amberlyst35 cation exchange resins, NKC-9 cation exchange resins, and D72 cation exchange resins, and zeolite catalysts including HZSM-5 and mordenite as catalysts, and using a distillation-reaction coupling process to directly hydrate and continuously produce dihydromyrcenol from dihydromyrcene as a raw material. Chinese patent application CN200910181288.6 discloses a process for synthesizing dihydromyrcenol, using an acid (including sulfuric acid, phosphoric acid, and p-toluenesulfonic acid) as a catalyst, and using an integrated system consisting of a jet reaction device, an oil-water separation device, and a distillation device. Chinese patent application CN201110059193.4 discloses a method for continuous production of dihydromyrcenol by fixed bed hydration, wherein the reaction materials are preheated and continuously enter a tubular reactor, and after being full, the overflow enters an oil-water separator for separation, the lower aqueous phase continues to circulate and enter the reaction system, and the oil layer enters a distillation tower for distillation. Chinese patent application CN201210126871.9 discloses a method for continuous production of dihydromyrcenol by tubular reactor. Chinese patent application CN201210060876.6 discloses a method for continuous preparation of dihydromyrcenol by reactive distillation, wherein a reactive distillation tower is equipped with a corrugated wire mesh filler and a solid acid catalyst, and the raw material dihydromyrcene and the hydration solvent are preheated to 80-120°C, 85-95°C, and 70-90°C, respectively, and the materials are fed from the upper, middle, and lower parts of the reaction section of the reactive distillation tower according to a flow ratio of (1-3): (1-3). The temperature of the tower bottom is controlled at 105-120°C, and the condensation temperature of the tower top is controlled at 50-70°C. The condensate is separated into an oil phase and an aqueous phase, part of the oil phase is refluxed to the tower top, and the aqueous phase and the remaining oil phase are respectively returned to the raw material tank for recycling. Chinese patent application CN201210501734.9 discloses a production method of dihydromyrcenol, which is to introduce dihydromyrcene (hereinafter referred to as DHM) and a hydrated low-viscosity organic solvent X into a forced circulation radiation flow fixed bed reactor for a circulation reaction; the liquid after the reaction is first separated from oil and water, and the product is distilled twice to obtain a product with a purity of 99.61%, a primary conversion rate of 10.6%, and a selectivity of 98.1%. Chinese patent application CN201510276832.0 discloses a method for preparing dihydromyrcenol. First, 36% acetic acid and water are put into a reactor and mixed evenly, and then heated to 80°C to 120°C; a homemade niobic acid catalyst is added to the reactor and the reaction is carried out at a constant temperature for 1h to 3h; the product obtained by the reaction is filtered, allowed to stand for stratification, and subjected to reduced pressure distillation to obtain the product.Chinese patent application CN201510183300.2 discloses a method for preparing dihydromyrcenol from turpentine, wherein α-pinene is hydrogenated in a specific manner to obtain high-yield pinane, which is then cracked to obtain high-yield dihydromyrcene, thereby maximizing the utilization of the raw material turpentine. Chinese patent application CN201811135211.0 discloses a method for synthesizing dihydromyrcenol by hydration, which is prepared by direct hydration of dihydromyrcene, using glacial acetic acid as a solvent and SO with a high specific surface area. 4 2 - / La 2 O 3 -ZrO 2 @CNTS superacid as a catalyst. Chinese patent application CN201811135280.1 A method for preparing dihydromyrcenol, prepared by direct hydration of dihydromyrcene, by using glacial acetic acid as a solvent and SO with a high specific surface area 4 2 - / ZrO 2 @CNTS superacid as a catalyst. Chinese patent application CN202211127038.6 discloses a method for preparing dihydromyrcenol, which uses an emulsifier and ultrasound to hydrate dihydromyrcene with water under the catalysis of liquid acid to generate dihydromyrcenol.

[0004] The main problems of the existing myrcene or dihydromyrcene hydration process are: first, the direct hydration reaction is accompanied by the dehydration cyclization side reaction of the alcohol, resulting in a low yield of the target product; second, a reaction-distillation coupling process is required, which results in a large energy loss. Summary of the invention

[0005] The invention provides a method for improving the yield of the hydration reaction of myrcene or dihydromyrcene in order to overcome the problems of low yield and high energy consumption of the direct hydration reaction of myrcene or dihydromyrcene. The composite catalyst of the invention is used to catalyze the hydration reaction at a relatively low temperature to obtain a target product.

[0006] In order to achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A method for improving the yield of the hydration reaction of myrcene or dihydromyrcene, comprising the following steps:

[0008] (1) Synthesis reaction: adding myrcene or dihydromyrcene, water, polar organic solvent and composite catalyst into a reaction kettle in a mass ratio of 100:(15-200):(100-800):(20-150), stirring at a temperature of 50° C. to 70° C., and reacting for 24 h to 48 h; the composite catalyst is composed of one or more of zirconium sulfate, titanium sulfate, α-hydroxy acid and divalent copper salt;

[0009] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0010] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0011] (4) Product neutralization: The product obtained in step (3) is neutralized with a dilute alkali solution, and then washed with water 2 to 3 times;

[0012] (5) Product fractionation: the product obtained in step (4) is transferred into a fractionation tower, and myrcene or dihydromyrcene is recovered by vacuum fractionation, and the recovered raw materials are added to a reaction kettle after being measured; the hydration product obtained by separation is linalool or dihydromyrcenol.

[0013] Preferably, the divalent copper salt in step (1) includes one or more of copper sulfate, copper nitrate, copper chloride, copper formate, and copper acetate.

[0014] Preferably, the α-hydroxycarboxylic acid in step (1) comprises one or more of tartaric acid, citric acid, malic acid, mandelic acid, lactic acid and glycolic acid.

[0015] Furthermore, the composite catalyst described in step (1) also includes boric acid.

[0016] Preferably, the composite catalyst described in step (1) is tartaric acid, boric acid, and divalent copper salt, and the mass ratio thereof is (5-10):(0.5-2):(0.2-1).

[0017] Preferably, the polar organic solvent in step (1) is one or more of acetic acid, propionic acid, butyric acid, valeric acid, ethyl acetate, and tetrahydrofuran.

[0018] Preferably, the product fractionation in step (5) comprises the following steps:

[0019] S1: First exhaust the air from the distillation tower to make the vacuum degree in the distillation tower ≤-0.10MPa;

[0020] S2: transporting the neutralized and washed product to the reactor of a distillation tower;

[0021] S3: heating to keep the bottom temperature at 110-120° C. and the top temperature at 80-90° C., reflux for 1-2 hours, and collect myrcene or dihydromyrcene at a reflux ratio of 10-13:1;

[0022] S4: raising the temperature to keep the bottom temperature at 130-140° C., the top temperature at 90-95° C., the reflux ratio at 15-20:1, and collecting the hydration product, such as linalool or dihydromyrcenol;

[0023] S5: raising the temperature to keep the bottom temperature at 140-150° C., the top temperature at 95-105° C., the reflux ratio at 15-20:1, and collecting ester products, such as linalyl or dihydromyrcenyl ester.

[0024] The invention also provides a synthetic fragrance, which comprises myrcene with a GC content of (10% to 30%), linalool or dihydromyrcenol (30% to 60%), and linalyl or dihydromyrcenyl ester (1% to 5%).

[0025] Furthermore, the linalyl or dihydromyrcenyl ester is one or more of acetate, propionate, butyrate and valerate.

[0026] Furthermore, the linalyl or dihydromyrcenyl ester is an α-hydroxycarboxylate; the α-hydroxycarboxylic acid includes one or more of tartaric acid, citric acid, malic acid, mandelic acid, lactic acid, and glycolic acid.

[0027] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0028] 1. The composite catalyst used in the present invention has the advantages of easy availability of raw materials, good repeatability, low corrosivity, easy separation from the product after the reaction, and easy industrial promotion and application.

[0029] 2. Compared with catalysts such as sulfuric acid, the composite catalyst used in the present invention has fewer side reactions and a lighter product color.

[0030] 3. Compared with the conventional reaction-distillation coupling process, the method of the present invention consumes a lot of heat because the conventional process requires heating the raw materials such as dihydromyrcene and hydrated solvent to boiling. However, the reaction temperature of the method of the present invention is lower than 70°C, which is beneficial to energy saving.

[0031] 4. Compared with the prior art, the method of the present invention has a GC content of cyclization byproducts in the dihydromyrcene hydration product lower than 1%, which is beneficial to improving the aroma of the product.

[0032] 5. The method of the present invention can obtain a fragrance containing linalyl and dihydromyrcenol esters, and the ester products in the product can provide a unique fragrance.

[0033] 6. After the reaction of the method of the present invention is completed, the solvent is recovered and the myrcene or dihydromyrcene is separated and can be reused, which greatly reduces the cost. DETAILED DESCRIPTION

[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0035] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0036] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0037] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0038] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0039] Sample analysis test method

[0040] Analytical instrument: Aglient7890A gas chromatograph, Agilent, USA; Chromatographic column: AT-35, quartz capillary column (60m×0.25mm×0.25μm). GC analysis conditions: Carrier gas, high-purity nitrogen; Program temperature: 70℃ (2min), increase to 150℃ at 50℃ / min, stay for 3min, increase to 230℃ at 30℃ / min, stay for 40min; Injection port temperature: 250℃, total flow rate 130.5ml / min, split ratio 50:1, septum purge 3ml / min; FID detection, detection port temperature: 250℃, hydrogen flow rate 40ml / min, air 450ml / min, nitrogen purge, 25ml / min. Injection volume 0.2ul.

[0041] The area normalization method was used to approximate the conversion amount of myrcene or dihydromyrcene by subtracting the GC content of myrcene or dihydromyrcene in the product from the GC content of myrcene or dihydromyrcene in the raw material.

[0042] Conversion rate of myrcene or dihydromyrcene = (GC content of myrcene or dihydromyrcene in the raw material - GC content of myrcene or dihydromyrcene in the product) / GC content of myrcene or dihydromyrcene in the raw material;

[0043] Selectivity of linalool or dihydromyrcenol = (GC content of linalool or dihydromyrcenol in the product) / (GC content of myrcene or dihydromyrcene in the raw material - GC content of myrcene or dihydromyrcene in the product).

[0044] Example 1

[0045] A method for improving the yield of dihydromyrcene hydration reaction comprises the following steps:

[0046] (1) Synthesis reaction: dihydromyrcene (GC content 85%, the same below), water, polar organic solvent, and composite catalyst are added to a reaction kettle in a mass ratio of 100:100:550:110, the temperature is 60° C., stirred, and the reaction time is 48 hours; the composite catalyst is composed of zirconium sulfate and copper sulfate in a mass ratio of 10:1; the polar solvent is acetic acid and ethyl acetate in a mass ratio of 25:30;

[0047] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0048] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0049] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 50% of the mass of the product was added with water, and washed three times;

[0050] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and dihydromyrcene is recovered by vacuum fractionation. The recovered raw material is metered and added into a reaction kettle; the hydrated product obtained by separation is dihydromyrcenol.

[0051] The product fractionation in step (5) comprises the following steps:

[0052] S1: First exhaust the air from the distillation tower to make the vacuum degree in the distillation tower ≤-0.10MPa;

[0053] S2: transporting the neutralized and washed product to the reactor of a distillation tower;

[0054] S3: heating to keep the bottom temperature at 110-120° C. and the top temperature at 80-90° C., reflux for 1.5 h, and collect myrcene or dihydromyrcene at a reflux ratio of 10-13:1;

[0055] S4: raising the temperature to keep the bottom temperature at 130-140° C., the top temperature at 90-95° C., the reflux ratio at 15-20:1, and collecting the hydration product, such as linalool or dihydromyrcenol;

[0056] S5: raising the temperature to keep the bottom temperature at 140-150° C., the top temperature at 95-105° C., the reflux ratio at 15-20:1, and collecting ester products, such as linalyl or dihydromyrcenyl ester.

[0057] The ester products, such as linalyl or dihydromyrcenyl ester, are collected.

[0058] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of dihydromyrcene was 70%, the selectivity of dihydromyrcenol was 88%, and the product also contained 1.7% of dihydromyrcenyl acetate.

[0059] Example 2

[0060] A method for improving the yield of dihydromyrcene hydration reaction comprises the following steps:

[0061] (1) Synthesis reaction: dihydromyrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:100:500:90, the temperature is 60°C, stirred, and the reaction time is 48 hours; the composite catalyst is composed of titanium sulfate and copper sulfate in a mass ratio of 8:1; the polar solvent is propionic acid and ethyl acetate in a mass ratio of 1:1;

[0062] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0063] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0064] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 80% of the mass of the product was added with water, and washed three times;

[0065] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and dihydromyrcene is recovered by vacuum fractionation. The recovered raw material is metered and added into a reaction kettle; the hydrated product obtained by separation is dihydromyrcenol.

[0066] The product fractionation step in step (5) is the same as that in Example 1.

[0067] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of dihydromyrcene was 72%, the selectivity of dihydromyrcenol was 90%, and the product also contained 2.0% of dihydromyrcenyl propionate.

[0068] Example 3

[0069] A method for improving the yield of dihydromyrcene hydration reaction comprises the following steps:

[0070] (1) Synthesis reaction: dihydromyrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:100:350:110, the temperature is 60°C, stirred, and the reaction time is 48 hours; the composite catalyst is composed of zirconium sulfate and copper sulfate in a mass ratio of 8:1; the polar solvent is butyric acid;

[0071] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0072] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0073] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 50% of the mass of the product was added with water, and washed three times;

[0074] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and myrcene or dihydromyrcene is recovered by vacuum fractionation. The recovered raw materials are metered and added to a reaction kettle; the hydrated product obtained by separation is dihydromyrcenol.

[0075] The product fractionation step in step (5) is the same as that in Example 1.

[0076] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of dihydromyrcene was 75%, the selectivity of dihydromyrcenol was 90.5%, and the product also contained 2.5% of dihydromyrcenyl butyrate.

[0077] Example 4

[0078] A method for improving the yield of dihydromyrcene hydration reaction comprises the following steps:

[0079] (1) Synthesis reaction: dihydromyrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:150:450:110, the temperature is 60°C, stirred, and the reaction time is 48 hours; the composite catalyst is composed of zirconium sulfate and copper sulfate in a mass ratio of 8:1; the polar solvent is valeric acid;

[0080] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0081] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0082] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 150% of the mass of the product was added with water, and washed twice;

[0083] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and dihydromyrcene is recovered by vacuum fractionation. The recovered raw material is metered and added into a reaction kettle; the hydrated product obtained by separation is dihydromyrcenol.

[0084] The product fractionation step in step (5) is the same as that in Example 1.

[0085] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of dihydromyrcene was 76%, the selectivity of dihydromyrcenol was 91%, and the product also contained 3.1% of dihydromyrcenyl valerate.

[0086] Example 5

[0087] A method for improving the yield of dihydromyrcene hydration reaction comprises the following steps:

[0088] (1) Synthesis reaction: dihydromyrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:150:450:80, the temperature is 60°C, stirred, and the reaction time is 48 hours; the composite catalyst is composed of tartaric acid, boric acid and copper sulfate in a mass ratio of 5:2:1; the polar solvent is acetic acid and tetrahydrofuran in a mass ratio of 2:1;

[0089] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0090] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0091] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 150% of the mass of the product was added with water, and washed twice;

[0092] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and dihydromyrcene is recovered by vacuum fractionation. The recovered raw material is metered and added into a reaction kettle; the hydrated product obtained by separation is dihydromyrcenol.

[0093] The product fractionation step in step (5) is the same as that in Example 1.

[0094] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of dihydromyrcene was 78%, the selectivity of dihydromyrcenol was 92%, and the product also contained 2.0% of dihydromyrcenyl acetate.

[0095] Example 6

[0096] A method for improving the yield of dihydromyrcene hydration reaction comprises the following steps:

[0097] (1) Synthesis reaction: dihydromyrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:150:450:125, the temperature is 60°C, stirring, and the reaction time is 48 hours; the composite catalyst is composed of lactic acid, boric acid and copper sulfate in a mass ratio of 10:1.5:1; the polar solvent is acetic acid and tetrahydrofuran in a mass ratio of 2:1;

[0098] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0099] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0100] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 150% of the mass of the product was added with water, and washed twice;

[0101] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and dihydromyrcene is recovered by vacuum fractionation. The recovered raw material is metered and added into a reaction kettle; the hydrated product obtained by separation is dihydromyrcenol.

[0102] The product fractionation step in step (5) is the same as that in Example 1.

[0103] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of dihydromyrcene was 77.8%, the selectivity of dihydromyrcenol was 92.3%, and the product also contained 1.8% of dihydromyrcenyl acetate and 0.7% of dihydromyrcenyl lactate.

[0104] Example 7

[0105] A method for improving the yield of dihydromyrcene hydration reaction comprises the following steps:

[0106] (1) Synthesis reaction: dihydromyrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:150:450:125, the temperature is 60°C, stirred, and the reaction time is 48 hours; the composite catalyst is composed of mandelic acid, boric acid and copper sulfate in a mass ratio of 10:1.5:1; the polar solvent is composed of acetic acid and tetrahydrofuran in a mass ratio of 2:1;

[0107] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0108] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0109] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 50% of the mass of the product was added with water, and washed twice;

[0110] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and dihydromyrcene is recovered by vacuum fractionation. The recovered raw material is metered and added into a reaction kettle; the hydrated product obtained by separation is dihydromyrcenol.

[0111] The product fractionation step in step (5) is the same as that in Example 1.

[0112] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of dihydromyrcene was 78.1%, the selectivity of dihydromyrcenol was 92.5%, and the product also contained 2.1% of dihydromyrcenyl acetate and 0.6% of dihydromyrcenyl mandelate.

[0113] Example 8

[0114] A method for improving the yield of dihydromyrcene hydration reaction comprises the following steps:

[0115] (1) Synthesis reaction: dihydromyrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:150:400:125, the temperature is 60°C, stirred, and the reaction time is 48 hours; the composite catalyst is composed of glycolic acid, boric acid and copper sulfate in a mass ratio of 10:1.5:1; the polar solvent is tetrahydrofuran;

[0116] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0117] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0118] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 100% of the mass of the product was added with water, and washed twice;

[0119] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and dihydromyrcene is recovered by vacuum fractionation. The recovered raw material is metered and added into a reaction kettle; the hydrated product obtained by separation is dihydromyrcenol.

[0120] The product fractionation step in step (5) is the same as that in Example 1.

[0121] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of dihydromyrcene was 78.5%, the selectivity of dihydromyrcenol was 91.8%, and the product also contained 0.9% of dihydromyrcenyl glycolate.

[0122] Example 9

[0123] A method for improving the yield of dihydromyrcene hydration reaction comprises the following steps:

[0124] (1) Synthesis reaction: dihydromyrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:150:400:105, the temperature is 60°C, stirred, and the reaction time is 48 hours; the composite catalyst is composed of citric acid, boric acid and copper sulfate in a mass ratio of 8:1.5:1; the polar solvent is composed of acetic acid and tetrahydrofuran in a mass ratio of 2:1;

[0125] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0126] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0127] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 200% of the mass of the product was added with water, and washed twice;

[0128] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and dihydromyrcene is recovered by vacuum fractionation. The recovered raw material is metered and added into a reaction kettle; the hydrated product obtained by separation is dihydromyrcenol.

[0129] The product fractionation step in step (5) is the same as that in Example 1.

[0130] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of dihydromyrcene was 78.8%, the selectivity of dihydromyrcenol was 92.3%, and the product also contained 1.8% of dihydromyrcenyl acetate.

[0131] Example 10

[0132] A method for improving the yield of dihydromyrcene hydration reaction comprises the following steps:

[0133] (1) Synthesis reaction: dihydromyrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:150:350:110, the temperature is 60°C, stirred, and the reaction time is 48 hours; the composite catalyst is composed of zirconium sulfate, lactic acid and copper sulfate in a mass ratio of 5:5:1; the polar solvent is acetic acid and tetrahydrofuran in a mass ratio of 2:1;

[0134] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0135] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0136] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 200% of the mass of the product was added with water, and washed twice;

[0137] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and dihydromyrcene is recovered by vacuum fractionation. The recovered raw material is metered and added into a reaction kettle; the hydrated product obtained by separation is dihydromyrcenol.

[0138] The product fractionation step in step (5) is the same as that in Example 1.

[0139] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of dihydromyrcene was 78.1%, the selectivity of dihydromyrcenol was 92.2%, and the product also contained 2.6% of dihydromyrcenyl acetate and 0.5% of dihydromyrcenyl lactate.

[0140] Embodiment 11

[0141] A method for improving the yield of dihydromyrcene hydration reaction comprises the following steps:

[0142] (1) Synthesis reaction: dihydromyrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:150:350:110, the temperature is 60°C, stirred, and the reaction time is 48 hours; the composite catalyst is composed of zirconium sulfate, malic acid and copper sulfate in a mass ratio of 5:5:1; the polar solvent is acetic acid and tetrahydrofuran in a mass ratio of 2:1;

[0143] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0144] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0145] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 150% of the mass of the product was added with water, and washed twice;

[0146] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and dihydromyrcene is recovered by vacuum fractionation. The recovered raw material is metered and added into a reaction kettle; the hydrated product obtained by separation is dihydromyrcenol.

[0147] The product fractionation step in step (5) is the same as that in Example 1.

[0148] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of dihydromyrcene was 78.5%, the selectivity of dihydromyrcenol was 92.4%, and the product also contained 2.3% of dihydromyrcenyl acetate and 0.3% of dihydromyrcenyl malate.

[0149] Example 12

[0150] A method for improving the yield of dihydromyrcene hydration reaction comprises the following steps:

[0151] (1) Synthesis reaction: dihydromyrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:150:350:110, the temperature is 60°C, stirred, and the reaction time is 48 hours; the composite catalyst is composed of titanium sulfate, tartaric acid and copper sulfate in a mass ratio of 5:5:1; the polar solvent is acetic acid and tetrahydrofuran in a mass ratio of 2:1;

[0152] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0153] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0154] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 150% of the mass of the product was added with water, and washed twice;

[0155] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and dihydromyrcene is recovered by vacuum fractionation. The recovered raw material is metered and added into a reaction kettle; the hydrated product obtained by separation is dihydromyrcenol.

[0156] The product fractionation step in step (5) is the same as that in Example 1.

[0157] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of dihydromyrcene was 78.5%, the selectivity of dihydromyrcenol was 92.4%, and the product also contained 2.3% of dihydromyrcenyl acetate and 0.2% of dihydromyrcenyl tartrate.

[0158] Example 13

[0159] A method for improving the yield of myrcene hydration reaction comprises the following steps:

[0160] (1) Synthesis reaction: Myrcene (GC content of 90%, the same below), water, polar organic solvent, and composite catalyst are added to a reaction kettle in a mass ratio of 100:150:350:110, the temperature is 60° C., stirred, and the reaction time is 48 hours; the composite catalyst is composed of zirconium sulfate, tartaric acid, and copper sulfate in a mass ratio of 5:5:1; the polar solvent is acetic acid and tetrahydrofuran in a mass ratio of 2:1;

[0161] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0162] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0163] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 150% of the mass of the product was added with water, and washed twice;

[0164] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and myrcene is recovered by vacuum fractionation. The recovered raw material is weighed and added into a reaction kettle; the hydrated product obtained by separation is linalool.

[0165] The product fractionation step in step (5) is the same as that in Example 1.

[0166] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of myrcene was 90.2%, the selectivity of linalool was 60.7%, and the product also contained 3.8% of linalyl acetate and 0.2% of myrcene tartrate.

[0167] Embodiment 14

[0168] A method for improving the yield of myrcene hydration reaction comprises the following steps:

[0169] (1) Synthesis reaction: Myrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:150:350:100, the temperature is 60°C, stirred, and the reaction time is 48 hours; the composite catalyst is composed of zirconium sulfate, lactic acid and copper sulfate in a mass ratio of 6:3:1; the polar solvent is acetic acid and tetrahydrofuran in a mass ratio of 2:1;

[0170] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0171] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0172] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 80% of the mass of the product was added with water, and washed three times;

[0173] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and myrcene is recovered by vacuum fractionation. The recovered raw material is weighed and added into a reaction kettle; the hydrated product obtained by separation is linalool.

[0174] The product fractionation step in step (5) is the same as that in Example 1.

[0175] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of myrcene was 94.2%, the selectivity of dihydromyrcenol was 65.3%, and the product also contained 3.8% of linalyl acetate and 0.7% of myrcenyl lactate.

[0176] Embodiment 15

[0177] A method for improving the yield of myrcene hydration reaction comprises the following steps:

[0178] (1) Synthesis reaction: Myrcene, water, polar organic solvent and composite catalyst are added into a reaction kettle in a mass ratio of 100:150:350:75, the temperature is 60°C, stirred, and the reaction time is 48 hours; the composite catalyst is composed of tartaric acid, boric acid and copper sulfate in a mass ratio of 5:1.5:1; the polar solvent is acetic acid and tetrahydrofuran in a mass ratio of 2:1;

[0179] (2) Catalyst recovery: After the reaction is completed, the reaction mixture is allowed to stand, the upper liquid product is filtered and then transferred to a solvent recovery tank, and then a polar organic solvent is added to the reactor to wash the catalyst at the bottom of the reactor. The washing liquid is filtered and then transferred to a solvent recovery tank;

[0180] (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering;

[0181] (4) Product neutralization: The product obtained in step (3) was neutralized with a dilute alkali solution, and then 150% of the mass of the product was added with water, and washed twice;

[0182] (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and myrcene is recovered by vacuum fractionation. The recovered raw material is weighed and added into a reaction kettle; the hydrated product obtained by separation is linalool.

[0183] The product fractionation step in step (5) is the same as that in Example 1.

[0184] After the reaction was completed, the product was sampled for GC analysis, which showed that the conversion rate of myrcene was 95.2%, the selectivity of dihydromyrcenol was 66.5%, and the product also contained 4.5% of linalyl acetate.

[0185] Comparative Example 1

[0186] Blank experiment. Synthesis reaction: Add dihydrolauric acid and water in a mass ratio of 1:10 into a reactor, start stirring, control the reaction temperature to 70°C, and the reaction time to 72h; no catalyst. After the reaction, samples were taken for GC analysis. The GC content of dihydromyrcene in the product was 85%, and no dihydromyrcenol was detected. It can be seen that dihydromyrcene does not react with water without a catalyst.

[0187] Comparative Example 2

[0188] Sulfuric acid was used as a catalyst. Other conditions were the same as in Example 1. The product was black in color. After the reaction was completed, the product was directly sampled, washed with water until neutral, and dissolved in ethyl acetate for GC analysis. By GC analysis of the product, it was found that there were more cyclized by-products, and the content of cyclized acetate was 10%. The selectivity of dihydromyrcenol was 53.5%, which was significantly lower than the selectivity of the target product of the present invention. The disadvantages of sulfuric acid as a catalyst are that it is highly corrosive, side reactions are prone to occur, and it is difficult to recycle after being dissolved in the product.

[0189] Comparative Example 3

[0190] Zirconium sulfate is used as a catalyst. Other conditions are the same as in Example 1. The color of the product is dark brown. After the reaction is completed, the product is directly sampled, washed with water to neutrality, and GC analysis is performed after dissolving in ethyl acetate. By performing GC analysis on the product, it is found that there are more cyclization by-products, and the content of cyclized acetate is 2%. The selectivity of dihydromyrcenol is 68%, which is lower than the selectivity of the target product of the present invention. Compared with sulfuric acid, when zirconium sulfate is used as a catalyst, although the cyclization by-products are reduced, the product color is dark, and a decolorization step needs to be added, thereby increasing the complexity of the process. The addition of divalent copper salt can effectively inhibit the occurrence of cyclization and color-forming side reactions, thereby reducing the complexity of the process and improving the quality of the product.

[0191] Comparative Example 4

[0192] Tartaric acid and boric acid are used as composite catalysts in a mass ratio of 5:2. Other conditions are the same as in Example 5. The product color is dark brown. After the reaction is completed, the product is directly sampled, washed with water to neutrality, and GC analysis is performed after dissolving in ethyl acetate. By performing GC analysis on the product, it is found that there are more cyclization by-products, and its cyclization acetate content is 4.5%. The selectivity of dihydromyrcenol is 65%, which is lower than the selectivity of the target product of the present invention. Compared with sulfuric acid, when tartaric acid and boric acid are used as catalysts, the cyclization by-products are reduced, but the product color is dark, and it is still necessary to increase the decolorization step, which also increases the complexity of the process. And in Example 5, adding a divalent copper salt to the composite catalyst can effectively inhibit the occurrence of cyclization and color-forming side reactions, reduce the complexity of the process, and improve the product quality.

[0193] Comparative Example 5

[0194] Sulfuric acid is used as a catalyst. Other conditions are the same as in Example 13. The color of the product is black. After the reaction is completed, the product is directly sampled, washed with water until neutral, and dissolved in ethyl acetate for GC analysis. By performing GC analysis on the product, it is found that there are more cyclization by-products such as dipentene, and the content of the cyclization by-products reaches 40.6%. The selectivity of linalool is 35%, which is significantly lower than the selectivity of the target product of the present invention. The disadvantage of sulfuric acid as a catalyst is that it is highly corrosive, side reactions are very likely to occur, and it is dissolved in the product and is not easy to be recycled.

[0195] The above contents are further detailed descriptions of the present invention in combination with specific / preferred implementations, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, they can also make several substitutions or modifications to these described embodiments without departing from the concept of the present invention, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for improving the yield of the hydration reaction of myrcene or dihydromyrcene, comprising the following steps: (1) Synthesis reaction: add myrcene or dihydromyrcene, water, polar organic solvent and composite catalyst into a reaction kettle at a mass ratio of 100:(15-200):(100-800):(20-150), stir at a temperature of 50°C-70°C, and react for 24h-48h; the composite catalyst is composed of one or more of zirconium sulfate, titanium sulfate, α-hydroxy acid and divalent copper salt; (2) Catalyst recovery: After the reaction is completed, let it stand, filter the upper liquid product and move it into a solvent recovery tank, then add a polar organic solvent into the reactor to wash the catalyst at the bottom of the reactor, filter the washing liquid and move it into a solvent recovery tank; (3) Solvent recovery: The solvent is recovered by vacuum distillation, and the recovered solvent is added to the reactor after metering; (4) Product neutralization: The product obtained in step (3) is neutralized with a dilute alkali solution, and then washed with water 2 to 3 times; (5) Product fractionation: The product obtained in step (4) is transferred into a fractionation tower, and myrcene or dihydromyrcene is recovered by vacuum fractionation. The recovered raw materials are weighed and added to a reaction kettle; the hydrated product obtained by separation is linalool or dihydromyrcenol.

2. The method for improving the hydration reaction yield of myrcene or dihydromyrcene according to claim 1, characterized in that: The divalent copper salt in step (1) includes one or more of copper sulfate, copper nitrate, copper chloride, copper formate, and copper acetate.

3. The method for improving the hydration reaction yield of myrcene or dihydromyrcene according to claim 1, characterized in that: The α-hydroxycarboxylic acid in step (1) includes one or more of tartaric acid, citric acid, malic acid, mandelic acid, lactic acid, and glycolic acid.

4. The method for improving the hydration reaction yield of myrcene or dihydromyrcene according to claim 1, characterized in that: The composite catalyst described in step (1) also includes boric acid.

5. The method for improving the hydration reaction yield of myrcene or dihydromyrcene according to claim 4, characterized in that: The composite catalyst is tartaric acid, boric acid and divalent copper salt, and the mass ratio thereof is (5-10): (0.5-2): (0.2-1).

6. The method for improving the hydration reaction yield of myrcene or dihydromyrcene according to claim 1, characterized in that: The polar organic solvent in step (1) is one or more of acetic acid, propionic acid, butyric acid, valeric acid, ethyl acetate and tetrahydrofuran.

7. The method for improving the hydration reaction yield of myrcene or dihydromyrcene according to claim 1, characterized in that: The product fractionation in step (5) comprises the following steps: S1: First exhaust the air from the distillation tower to make the vacuum degree in the distillation tower ≤-0.10MPa; S2: transporting the neutralized and washed product to the reactor of a distillation tower; S3: heating to keep the bottom temperature at 110-120° C. and the top temperature at 80-90° C., reflux for 1-2 hours, and collect myrcene or dihydromyrcene at a reflux ratio of 10-13:1; S4: raising the temperature to keep the bottom temperature at 130-140° C., the top temperature at 90-95° C., the reflux ratio at 15-20:1, and collecting the hydration product, such as linalool or dihydromyrcenol; S5: Raise the temperature to keep the bottom temperature at 140-150° C., the top temperature at 95-105° C., the reflux ratio at 15-20:1, and collect ester products, such as linalyl or dihydromyrcenyl ester.