A process for the preparation of farnesol from nerolidol

Abstract

The application discloses a method for preparing farnesol from nerolidol, wherein a composite catalytic system composed of a phosphate and a vanadate or molybdate is used to perform isomerization reaction on nerolidol to prepare farnesol. The synthetic route of the application is simple, the catalytic system is simple and easy to obtain, the reaction process is simple, the isomerization reaction has very high chemical selectivity and stereoselectivity, and the synthesis method of farnesol is greatly simplified.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of fine chemical industry, and particularly relates to a method for preparing farnesol from nerolidol. BACKGROUND

[0002] Nerolidol, English name Nerolido, is a colorless to grass yellow syrup oil liquid, has a weak rose and apple-like fragrance, and is accompanied by very sweet, fresh, lasting fragrance, and is mainly used for preparing apple, mixed fruit and citrus essence. The high-purity nerolidol can be prepared by taking 98-102 DEG C / 53 Pa fraction of Peru balsam oil or neroli oil by vacuum fractional distillation. The synthetic nerolidol is a colorless liquid, which is a mixture of (±)-cis- and (±)-trans-nerolidol, and has a lasting, mild floral fragrance. Nerolidol exists in many natural essential oils, has a pleasant mixed woody, floral and fresh fragrance, and has been widely used in the preparation of many complex floral fragrances as a commonly used spice. As a valuable spice, nerolidol not only has a wide range of uses, but also its derivatives have important commercial value.

[0003] Farnesol is a chain sesquiterpene compound, also known as farnesol, and English name farnesol. Farnesol has a mild and delicate floral fragrance with a characteristic of lily, has a good fragrance fixing effect, and is an important component of high-grade floral essence; in addition, it has a bacteriostatic effect, and can be used in deodorants and cosmetics; it is also a component of insect juvenile hormone, and can be used for manufacturing pesticides. Farnesol exists in the essential oils of flowers, leaves and seeds of plants, such as rose grass, lime peel, citrus flowers, pine needles of Douglas fir, champagne flowers, Peruvian balsam, etc. There are many synthesis routes of farnesol, for example, nerolidol isomerization method, alkyne addition phosphine salt and aldehyde condensation, ketone (geranyl propyl ketone) and ester synthesis, alcohol aldehyde condensation and halide addition, etc. These methods have advantages and disadvantages, and the steps are relatively more when alkynes, ketones and halides are used. Although the yield of each step is relatively high, the total yield is relatively low, and the separation and purification is also a big problem. The isomerization of nerolidol to farnesol is the shortest route and has good selectivity, and the reaction product is relatively single, but the current problem is that the conversion rate is low. SUMMARY

[0004] In order to improve the conversion rate and selectivity of the isomerization reaction of nerolidol, the present application provides a new catalytic system. By using the catalytic system of the present application, farnesol can be efficiently prepared by isomerization of nerolidol. The catalytic system of the present application is simple, and has very high chemical selectivity and stereoselectivity, which can greatly improve the preparation efficiency of farnesol, and the catalytic cost is low.

[0005] The technical scheme provided by the present application is as follows:

[0006] In a first aspect of the present application, a composite catalyst system is provided, comprising: (a) a phosphoric acid ester, (b) a vanadate or molybdate; wherein the molar ratio of component (a) to component (b) is 1:1 to 2:1, preferably 1.05 to 1.3:1.

[0007] In the catalyst system of the present application, the phosphoric acid ester is preferably at least one of dimethyl phosphate, diethyl phosphate, dipropyl phosphate, dibutyl phosphate, diphenyl phosphate, dibenzyl phosphate, 2-biphenyldiphenyl phosphate, phosphite, 1-naphthyl phosphate, binaphthyl phosphate, isooctyl phosphate, trioctyl phosphate.

[0008] In the catalyst system of the present application, the vanadate is preferably at least one of sodium orthovanadate, sodium metavanadate, sodium metavanadate dihydrate, vanadyl acetate, vanadyl stearate, ammonium metavanadate, potassium metavanadate, cesium metavanadate, lithium metavanadate, cesium vanadate.

[0009] In the catalyst system of the present application, the molybdate is preferably at least one of ammonium molybdate phosphate, ammonium molybdate, potassium molybdate, ammonium dimolybdate, ammonium tetramolybdate, lithium molybdate.

[0010] In a second aspect of the present application, a method for synthesizing farnesol from nerolidol by isomerization reaction is provided, using the composite catalyst system described above as the catalyst.

[0011] In the present application, the molar amount of the composite catalyst system (calculated based on vanadate or molybdate) is 0.1% to 4%, preferably 0.1% to 0.5%, based on the molar amount of nerolidol.

[0012] In the present application, the isomerization reaction solvent is preferably one or more of benzene, toluene, xylene, methyl tert-butyl ether, ethyl acetate, dichloromethane, diethyl ether, tetrahydrofuran, n-hexane, more preferably toluene or xylene.

[0013] Preferably, the mass ratio of nerolidol to solvent is 0.2:1 to 2:1, preferably 1:1.

[0014] In the present application, the reaction temperature is preferably 100°C to 200°C, preferably 140°C to 190°C; the reaction time is 1 to 8 hours, preferably 4 to 7 hours.

[0015] As a specific embodiment, in the isomerization reaction of the present application, nerolidol is dissolved in a solvent, and the weighed components of the catalyst are added to the reaction kettle at one time, and the reaction kettle is replaced with nitrogen and heated to perform the isomerization reaction.

[0016] Compared with the prior art, the present application has the following positive effects:

[0017] The composite catalytic system of this invention is simple, and all components are commercially available. Using this catalytic system to prepare farnesol is a simple route with a conversion rate of up to 95% and a selectivity of up to 96%. The operation is simple and the cost is controllable. Detailed Implementation

[0018] The following specific embodiments are only for illustrating the present invention, but these examples are only part of the content of the present invention and do not limit the application of the present invention in other fields.

[0019] All raw materials used in the examples are conventional raw materials in the art, and the purity specifications used are analytical grade or chemically pure.

[0020] The source information of the raw materials is as follows:

[0021] Potassium metavanadate, sodium orthovanadate, dibutyl phosphate, diphenyl phosphate, naphthol phosphate, and isooctyl phosphate (CAS: 12645-31-7) are from Anaiji Chemical.

[0022] Ammonium metavanadate was sourced from Shandong Xiya Chemical Co., Ltd., and ammonium molybdate was sourced from Tianjin Damao Chemical Reagent Factory.

[0023] Nerolidol and toluene are from Merck.

[0024] The catalyst activity of the isomerization reaction was determined by qualitative and quantitative analysis of the components in the reaction solution. The conditions of the GC analytical instrument used were as follows:

[0025] Instrument Model: Shimadzu GC2010

[0026] Column: DB-5 (30m 0.25mm 0.25μm)

[0027] Column temperature program: First, maintain at 35℃ for 10 min, then increase to 280℃ at a rate of 10℃ / min, and maintain at this temperature for 10 min.

[0028] Detector temperature: 300℃

[0029] Carrier gas: 1 bar

[0030] Air: 0.3 bar

[0031] Gas (H2): 0.3 bar

[0032] Sample quality analysis was performed using the internal standard method. It should include:

[0033]

[0034] In the formula, m1 is the mass of a certain product, m is the mass of the internal standard, a1 is the peak area of ​​the product detected in gas chromatography, and a is the peak area of ​​the internal standard. k is a correction coefficient related to the analyte and detection conditions.

[0035] Example 1

[0036] Toluene and nerolidol were dried to remove water before the reaction, with a water content of <0.01%. The dried nerolidol (111.1 g, 0.5 mol), toluene (110 g), ammonium metavanadate (58.5 mg, 0.5 mmol), and dibutyl phosphate (115.6 mg, 0.55 mmol) were added sequentially to the reactor. The reactor was tightened, nitrogen was purged three times, and the mixture was heated to 180°C for 5 hours. GC analysis showed a conversion rate of 91% and a farnesol selectivity of 90%.

[0037] Example 2

[0038] Toluene and nerolidol were dried to remove water before the reaction, with a water content of <0.01%. The dried nerolidol (133.3 g, 0.6 mol), toluene (120 g), potassium metavanadate (82.8 mg, 0.6 mmol), and diphenyl phosphate (165.1 mg, 0.66 mmol) were added sequentially to the reactor. The reactor was tightened, nitrogen was purged three times, and the mixture was heated to 170°C for 6 hours. GC analysis showed a conversion rate of 95% and a farnesol selectivity of 96%.

[0039] Example 3

[0040] Toluene and nerolidol were dried to remove water before the reaction, with a water content of <0.01%. The dried nerolidol (155.54 g, 0.7 mol), toluene (100 g), ammonium molybdate (137.2 mg, 0.7 mmol), and isooctyl phosphate (191.7 mg, 0.84 mmol) were added sequentially to the reactor. The reactor was tightened, nitrogen was purged three times, and the mixture was heated to 180°C for 5 hours. GC analysis showed a conversion rate of 89% and a farnesol selectivity of 92%.

[0041] Example 4

[0042] Toluene and nerolidol were dried to remove water before the reaction, with a water content of <0.01%. The dried nerolidol (88.9 g, 0.4 mol), 150 g toluene, sodium orthovanadate (147.1 mg, 0.8 mmol), and naphthol phosphate (334.3 mg, 0.96 mmol) were added sequentially to the reactor. The reactor was tightened, nitrogen was purged three times, and the mixture was heated to 150°C for 6 hours. GC analysis showed a conversion rate of 90% and a farnesol selectivity of 93%.

[0043] Comparative Example 1

[0044] Toluene and nerolidol were dried to remove water before the reaction, with a water content of <0.01%. Dried nerolidol (22.2 g, 0.1 mol), toluene (40 g), and ammonium metavanadate (29.2 mg, 0.25 mmol) were added sequentially to the reaction flask. Nitrogen gas was purged three times, and the mixture was heated to 180°C. Toluene was removed via a water separator during the reaction. The reaction was carried out for 5 hours. GC analysis showed a conversion rate of 39.2% and a farnesol selectivity of 95.6%.

[0045] Comparative Example 2

[0046] Toluene and nerolidol were dried to remove water before the reaction, with a water content of <0.01%. Dried nerolidol (22.2 g, 0.1 mol), 40 g toluene, and tributyl orthovanadate (68.6 mg, 0.24 mmol) were added sequentially to the reaction flask. Nitrogen gas was purged three times, and the mixture was heated to 180°C. Toluene was removed via a water separator during the reaction. The reaction time was 4.5 h. GC analysis showed a conversion rate of 39.6% and a farnesol selectivity of 94%.

Claims

1. A method for synthesizing farnesol from nerolidol by isomerization reaction, characterized in that, The nerolidol is dissolved in a solvent, components (a) phosphates, component (b) vanadate or molybdate are added as a composite catalyst into a reaction kettle, the reaction kettle is replaced with nitrogen and heated to perform isomerization; wherein, the molar ratio of component (a) to component (b) is 1:1-2:1, the phosphates are selected from at least one of dimethyl phosphate, diethyl phosphate, dipropyl phosphate, dibutyl phosphate, diphenyl phosphate, dibenzyl phosphate, 2-biphenyldiphenyl phosphate, phosphite, 1-naphthyl phosphate, binaphthol phosphate, isooctyl phosphate, trioctyl phosphate.

2. The method of claim 1, wherein, The molar ratio of component (a) to component (b) is 1.05-1.3:

1.

3. The method of claim 1, wherein, The vanadate is selected from at least one of sodium orthovanadate, sodium metavanadate, sodium metavanadate dihydrate, vanadyl acetate, vanadyl stearate, ammonium metavanadate, potassium metavanadate, cesium metavanadate, lithium metavanadate, cesium vanadate.

4. The method of claim 1, wherein, The molybdate is selected from at least one of ammonium molybdate, ammonium molybdate, potassium molybdate, ammonium dimolybdate, ammonium tetramolybdate, lithium molybdate.

5. The method according to any one of claims 1 to 4, wherein, The molar amount of the composite catalyst is 0.1-4% based on the molar amount of nerolidol, calculated based on vanadate or molybdate.

6. The method of claim 5, wherein, The molar amount of the composite catalyst is 0.1-0.5% based on the molar amount of nerolidol, calculated based on vanadate or molybdate.

7. The method of claim 1, wherein, The reaction temperature is 100-200°C; the reaction time is 1-8h.

8. The method of claim 1, wherein, The reaction temperature is 140-190°C; the reaction time is 4-7h.

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