A synthesis process of 1,8-cineole

Abstract

The invention discloses a kind of synthesis technique of 1,8 cineole, belong to 1,8 cineole technical field, the synthesis technique comprises the following steps:α-terpineol is added into autoclave, autoclave is warming up to 55~65 DEG C, then stirring and adding catalyst thereto, after addition is complete, then carbon dioxide is filled into autoclave, constant temperature stirring reaction 8~12h, after completion of the reaction, pressure relief discharging, catalyst is separated using an external magnetic field, residual product 1,8 cineole. The present invention utilizes the magnetic catalyst for the homemade load with active component phosphotungstic acid to carry out the synthesis of 1,8 cineole, after testing, the conversion rate of α-terpineol reaches 95.1%~96.1%, and the selectivity of 1,8 cineole reaches 51.3%~52.5%, relative to prior art, the synthetic method provided by the present invention can significantly improve the conversion rate of α-terpineol and the selectivity of 1,8 cineole.

Description

Technical Field

[0001] The invention belongs to the technical field of 1,8-cineole, and particularly relates to a synthesis process of 1,8-cineole. Background Art

[0002] 1,8-Cineole has excellent antibacterial, anti-inflammatory, antiseptic, and insecticide and mosquito repellent properties. It is widely used in flavors and fragrances, hygiene, and medicine, and has broad market prospects. Currently, the main methods for preparing 1,8-cineole include natural extraction and chemical synthesis. Natural extraction suffers from issues such as low eucalyptus oil yield, high levels of impurities, and low extraction yield. Therefore, chemical synthesis is the primary method for preparing 1,8-cineole.

[0003] The synthesis of 1,8-cineole can be divided into a liquid acid catalysis method and a solid acid catalyst method according to the type of catalyst. Among them, many improvements have been made to the solid acid catalysis method in the prior art. For example, Chinese invention patent application number 201410063222.8 discloses a method for preparing a solid heteropolyacid catalyst for synthesizing 1,8-cineole. This invention patent uses silica as a carrier to load highly selective phosphotungstic acid. The prepared catalyst has excellent stability and is environmentally friendly. Using this preparation method to synthesize 1,8-cineole, a 97.93% α-terpineol conversion rate and 37.35% 1,8-cineole selectivity were finally obtained. Summary of the Invention

[0004] The present invention aims to provide a synthesis process for 1,8-cineole, aiming to further improve the conversion rate of α-terpineol and the selectivity of 1,8-cineole.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A synthesis process for 1,8-cineole comprises the following steps:

[0007] α-terpineol is added to the autoclave, the temperature of the autoclave is raised to 55-65° C., and the catalyst is added thereto with stirring. After the addition is completed, carbon dioxide is filled into the autoclave until the pressure in the autoclave reaches 20-25 MPa. The autoclave is then stirred and heated to 80-100° C., and the reaction is stirred at a constant temperature for 8-12 hours. After the reaction is completed, the pressure is released and the material is discharged. The catalyst is separated by an external magnetic field, and the remaining product 1,8-cineole is obtained.

[0008] Furthermore, the usage ratio of α-terpineol and catalyst is 200g:7-10g.

[0009] Furthermore, the catalyst is prepared by the following steps:

[0010] Add the amino magnetic carrier and phosphotungstic acid to dichloromethane with stirring. After the addition is completed, heat to 80°C and reflux for 12 hours. After completion, remove the solvent under reduced pressure, wash the remaining solute with ether 3 to 5 times, and then place it in a vacuum drying oven at 60 to 70°C and dry it for 12 hours. After drying, cool it to room temperature to obtain a catalyst.

[0011] Furthermore, the usage ratio of the dichloromethane, the amino magnetic carrier and the phosphotungstic acid is 100 mL: 2 g: 11.5-14.4 g.

[0012] Furthermore, the amino magnetic carrier is prepared by the following steps:

[0013] Titanium silicate magnetic carrier was added to a 75% by mass ethanol aqueous solution with stirring, ultrasonic stirring was performed for 30 minutes, 3-aminopropyltriethoxysilane was added thereto with stirring, and stirring was performed at room temperature for 3 hours. The solid component was collected with a magnet, and the solid component was washed with deionized water for 3 to 5 times. After washing, it was dried at room temperature for 12 hours to obtain an amino magnetic carrier.

[0014] Furthermore, the usage ratio of the anhydrous ethanol, the titanium silicate magnetic carrier and the 3-aminopropyltriethoxysilane is 200 mL:10 g:4-5 g.

[0015] Furthermore, the titanium silicon magnetic carrier is prepared by the following steps:

[0016] Add cobalt nitrate hexahydrate and ferric nitrate nonahydrate to the hydrochloric acid solution. After the addition is completed, place the system in a water bath at 70-80°C and stir at a constant temperature for 1-2 hours. After the stirring is completed, add citric acid thereto. After the addition is completed, continue stirring in a water bath at a constant temperature for 30-50 minutes. After the addition is completed, add titanium silicon molecular sieve thereto and stir. Continue stirring in a water bath at a constant temperature for 2-3 hours. After the completion, place the system in a constant temperature drying oven at 40-50°C and dry to constant weight to obtain a magnet carrier. Place the magnet carrier in a muffle furnace and roast at 500-550°C for 2 hours. After the roasting is completed, obtain a titanium silicon magnetic carrier.

[0017] Furthermore, the molar concentration of the hydrochloric acid solution is 0.5 mol / L.

[0018] Furthermore, the molar concentration of the citric acid is equal to the sum of the molar concentrations of the metal ions in the mixed solution.

[0019] Furthermore, the usage ratio of the hydrochloric acid solution, cobalt nitrate hexahydrate, ferric nitrate nonahydrate and titanium silicon molecular sieve is 500 mL:14.5 g:40.4 g:50 g.

[0020] Beneficial effects of the present invention:

[0021] The present invention utilizes a homemade magnetic catalyst loaded with phosphotungstic acid as an active component to synthesize 1,8-cineole. Simultaneously, the synthesis process of the present invention utilizes carbon dioxide as a reaction medium, thereby increasing the yield of the product 1,8-cineole without the involvement of a solvent. Testing shows that the conversion rate of α-terpineol reaches 95.1% to 96.1%, and the selectivity of 1,8-cineole reaches 51.3% to 52.5%. Compared with the prior art, the synthesis method provided by the present invention can significantly increase the conversion rate of α-terpineol and the selectivity of 1,8-cineole.

[0022] Among them, the present invention prepares a magnetic catalyst loaded with an active component, phosphotungstic acid. Specifically, the present invention uses titanium silicon molecular sieve as a carrier, loads the magnetic component - nano CoFe2O4 particles on the carrier surface, then uses 3-aminopropyltriethoxysilane to perform surface amination treatment on the catalyst loaded with the magnetic component, and finally loads the active component phosphotungstic acid to obtain the catalyst. The main purposes and effects of the above preparation process are as follows:

[0023] First, the present invention utilizes the three-dimensional pore structure of titanium silicate molecular sieve. The special structure of titanium silicate molecular sieve gives it a large specific surface area and excellent adsorption performance. The present invention uses titanium silicate molecular sieve as a carrier material to increase the loading amount of the active component phosphotungstic acid, thereby helping to improve the conversion rate of α-terpineol and the selectivity of 1,8-cineole.

[0024] Then, the present invention introduces a magnetic component, nano-CoFe2O4 particles, into the surface of the titanium silicon molecular sieve to improve the separation efficiency of the finally prepared catalyst, thereby helping to reduce the influence of the catalyst on the purity of the synthetic product and improving the recovery rate of the finally prepared catalyst.

[0025] Finally, the present invention uses 3-aminopropyltriethoxysilane to perform surface amination treatment on the titanium silicalite carrier loaded with the magnetic component. On the one hand, the hydrolysis of the silicon-oxygen bond in the 3-aminopropyltriethoxysilane can improve the dispersibility of the carrier and reduce the agglomeration effect of the finally prepared catalyst. On the other hand, the 3-aminopropyltriethoxysilane contains an amino group, which can improve the link strength between the phosphotungstic acid active component and the carrier through coordination and hydrogen bonding, thereby further reducing the influence of the catalyst on the purity of the synthetic product. At the same time, the improvement of the stability of the active component helps to further improve the conversion rate of α-terpineol and the selectivity of 1,8-cineole. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Example 1

[0028] Preparation of catalyst:

[0029] S1. Add 14.5 g of cobalt nitrate hexahydrate (99%; purchased from Sinopharm Chemical Reagent Co., Ltd.) and 40.4 g of ferric nitrate nonahydrate (99.99%; purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) to 500 mL of 0.5 mol / L hydrochloric acid solution (self-prepared). After the addition is complete, place the system in a 70°C water bath and stir at this temperature for 1 h. After stirring, add citric acid (99.5%; purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) and control the reaction mixture to obtain a 500 mL 0.5 mol / L hydrochloric acid solution. The molar concentration of the substance of the citric acid is equal to the sum of the molar concentrations of the metal ions in the mixed solution. After the addition is completed, the mixture is stirred in a constant temperature water bath for 30 minutes. After completion, 50 g of titanium silicate molecular sieve (TS-1; purchased from Sinopharm Chemical Reagent Co., Ltd.) is added thereto with stirring, and the mixture is stirred in a constant temperature water bath for 2 hours. After completion, the mixture is placed in a constant temperature drying oven at 40° C. and dried to constant weight to obtain a magnetic carrier. The magnetic carrier is placed in a muffle furnace and calcined at 500° C. for 2 hours. After calcination, a titanium silicate magnetic carrier is obtained.

[0030] S2. 10 g of titanium silicate magnetic carrier was added to 200 mL of ethanol aqueous solution (75% by weight of powder water; purchased from Sinopharm Chemical Reagent Co., Ltd.) with stirring, and ultrasonically stirred for 30 min. 4 g of 3-aminopropyltriethoxysilane (99%; purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) was then added thereto with stirring, and stirred at room temperature for 3 h. The solid component was collected with a magnet, and then the solid component was washed with deionized water 3 times, and then dried at room temperature for 12 h to obtain an amino magnetic carrier.

[0031] S3. Add 2 g of amino magnetic carrier and 11.5 g of phosphotungstic acid (99%; purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) to 100 mL of dichloromethane (99%; purchased from Sinopharm Chemical Reagent Co., Ltd.) with stirring. After the addition is completed, heat to 80°C and reflux for 12 hours. After completion, remove the solvent under reduced pressure, wash the remaining solute three times with ether, and then place it in a vacuum drying oven at 60°C and dry it for 12 hours. After drying, cool to room temperature to obtain the catalyst.

[0032] Example 2

[0033] Preparation of catalyst:

[0034] S1. Add 14.5 g of cobalt nitrate hexahydrate (99%; purchased from Sinopharm Chemical Reagent Co., Ltd.) and 40.4 g of ferric nitrate nonahydrate (99.99%; purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) to 500 mL of 0.5 mol / L hydrochloric acid solution (self-prepared). After the addition is complete, place the system in a 75°C water bath and stir at this temperature for 2 h. After the stirring is complete, add citric acid (99.5%; purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) and control the reaction mixture to obtain a 500 mL solution of 0.5 mol / L hydrochloric acid solution. The molar concentration of the substance of the citric acid is equal to the sum of the molar concentrations of the metal ions in the mixed solution. After the addition is completed, the mixture is stirred in a constant temperature water bath for 50 minutes. After completion, 50g of titanium silicate molecular sieve (TS-1; purchased from Sinopharm Chemical Reagent Co., Ltd.) is added thereto with stirring, and the mixture is stirred in a constant temperature water bath for 3 hours. After completion, the mixture is placed in a constant temperature drying oven at 45°C and dried to constant weight to obtain a magnetic carrier. The magnetic carrier is placed in a muffle furnace and calcined at 550°C for 2 hours. After calcination, a titanium silicate magnetic carrier is obtained.

[0035] S2. 10 g of titanium silicate magnetic carrier was added to 200 mL of ethanol aqueous solution (75% by weight of powder water; purchased from Sinopharm Chemical Reagent Co., Ltd.) with stirring, and ultrasonically stirred for 30 min. 4.5 g of 3-aminopropyltriethoxysilane (99%; purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) was then added thereto with stirring, and stirred at room temperature for 3 h. The solid component was collected with a magnet, and then the solid component was washed with deionized water 5 times, and then dried at room temperature for 12 h to obtain an amino magnetic carrier;

[0036] S3. Add 2 g of amino-containing magnetic carrier and 14.4 g of phosphotungstic acid (99%; purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) to 100 mL of dichloromethane (99%; purchased from Sinopharm Chemical Reagent Co., Ltd.) with stirring. After the addition is completed, heat to 80°C and reflux for 12 hours. After completion, remove the solvent under reduced pressure, wash the remaining solute with ether 5 times, and then place it in a vacuum drying oven at 60°C and dry it for 12 hours. After drying, cool to room temperature to obtain a catalyst.

[0037] Example 3

[0038] Preparation of catalyst:

[0039] S1. Add 14.5 g of cobalt nitrate hexahydrate (99%; purchased from Sinopharm Chemical Reagent Co., Ltd.) and 40.4 g of ferric nitrate nonahydrate (99.99%; purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) to 500 mL of 0.5 mol / L hydrochloric acid solution (self-prepared). After the addition is complete, place the system in an 80°C water bath and stir at this temperature for 2 h. After the stirring is complete, add citric acid (99.5%; purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) and control the reaction mixture to obtain a 500 mL solution of 0.5 mol / L hydrochloric acid solution. The molar concentration of the substance of the citric acid is equal to the sum of the molar concentrations of the metal ions in the mixed solution. After the addition is completed, the mixture is stirred in a constant temperature water bath for 50 minutes. After completion, 50 g of titanium silicate molecular sieve (TS-1; purchased from Sinopharm Chemical Reagent Co., Ltd.) is added thereto with stirring, and the mixture is stirred in a constant temperature water bath for 3 hours. After completion, the mixture is placed in a constant temperature drying oven at 50° C. and dried to constant weight to obtain a magnetic carrier. The magnetic carrier is placed in a muffle furnace and calcined at 550° C. for 2 hours. After calcination, a titanium silicate magnetic carrier is obtained.

[0040] S2. 10 g of titanium silicate magnetic carrier was added to 200 mL of ethanol aqueous solution (75% by weight of powder water; purchased from Sinopharm Chemical Reagent Co., Ltd.) with stirring, and ultrasonically stirred for 30 min. 5 g of 3-aminopropyltriethoxysilane (99%; purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) was then added thereto with stirring, and stirred at room temperature for 3 h. The solid component was collected with a magnet, and then the solid component was washed with deionized water 5 times, and then dried at room temperature for 12 h to obtain an amino magnetic carrier;

[0041] S3. Add 2 g of amino-containing magnetic carrier and 14.4 g of phosphotungstic acid (99%; purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) to 100 mL of dichloromethane (99%; purchased from Sinopharm Chemical Reagent Co., Ltd.) with stirring. After the addition is completed, heat to 80°C and reflux for 12 hours. After completion, remove the solvent under reduced pressure, wash the remaining solute with ether 5 times, and then place it in a vacuum drying oven at 70°C and dry it for 12 hours. After drying, cool to room temperature to obtain a catalyst.

[0042] Comparative Example 1

[0043] Comparative Example 1 is the control group of Example 2, except that the amination process in Example 2 is removed. That is, the catalyst in Comparative Document 1 is prepared by the following steps:

[0044] S1. Add 14.5 g of cobalt nitrate hexahydrate (99%; purchased from Sinopharm Chemical Reagent Co., Ltd.) and 40.4 g of ferric nitrate nonahydrate (99.99%; purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) to 500 mL of 0.5 mol / L hydrochloric acid solution (self-prepared). After the addition is complete, place the system in a 75°C water bath and stir at this temperature for 2 h. After the stirring is complete, add citric acid (99.5%; purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) and control the reaction mixture to obtain a 500 mL solution of 0.5 mol / L hydrochloric acid solution. The molar concentration of the substance of the citric acid is equal to the sum of the molar concentrations of the metal ions in the mixed solution. After the addition is completed, the mixture is stirred in a constant temperature water bath for 50 minutes. After completion, 50g of titanium silicate molecular sieve (TS-1; purchased from Sinopharm Chemical Reagent Co., Ltd.) is added thereto with stirring, and the mixture is stirred in a constant temperature water bath for 3 hours. After completion, the mixture is placed in a constant temperature drying oven at 45°C and dried to constant weight to obtain a magnetic carrier. The magnetic carrier is placed in a muffle furnace and calcined at 550°C for 2 hours. After calcination, a titanium silicate magnetic carrier is obtained.

[0045] S2. Add 2 g of titanium silicate magnetic carrier and 14.4 g of phosphotungstic acid (99%; purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) to 100 mL of dichloromethane (99%; purchased from Sinopharm Chemical Reagent Co., Ltd.) with stirring. After the addition is completed, heat to 80°C and reflux for 12 hours. After completion, remove the solvent under reduced pressure, wash the remaining solute with ether 5 times, and then place it in a vacuum drying oven at 60°C and dry it for 12 hours. After drying, cool to room temperature to obtain the catalyst.

[0046] Comparative Example 2

[0047] Comparative Example 2 is the control group of Example 2, in which the magnetization and amination processes in Example 2 are removed, that is, the catalyst in Comparative Document 2 is prepared by the following steps:

[0048] To 100 mL of dichloromethane (99%; purchased from Sinopharm Chemical Reagent Co., Ltd.) was added 2 g of titanium silicate molecular sieve (TS-1; purchased from Sinopharm Chemical Reagent Co., Ltd.) and 14.4 g of phosphotungstic acid (99%; purchased from Shanghai MacLean Biochemical Technology Co., Ltd.) with stirring. After the addition was completed, the temperature was raised to 80°C and refluxed for 12 hours. After completion, the solvent was removed under reduced pressure, and the remaining solute was washed 5 times with ether and then placed in a vacuum drying oven at 70°C for 12 hours. After drying, the mixture was cooled to room temperature to obtain a catalyst.

[0049] Example 4

[0050] A synthesis process for 1,8-cineole comprises the following steps:

[0051] 200g of α-terpineol (98%; purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) was added to the autoclave, the autoclave was warming up to 55°C, and then the catalyst prepared by Example 1 of 7g was stirred and added thereto. After completion of the addition, carbon dioxide (99.8%; purchased from Shanghai Canghai Industrial Gas Co., Ltd.) was charged into the autoclave, and the pressure in the autoclave reached 20Mpa. The autoclave was stirred and warmed to 80°C, and the reaction was stirred at a constant temperature for 8h. After completion of the reaction, the pressure was released and the catalyst was separated by an external magnetic field. The residual product was analyzed and detected by gas chromatograph (Agilent-7890-GC) and gas chromatography-mass spectrometry (Shimadzu, Japan) to determine the composition of the product. The conversion of α-terpineol was 95.1%, and the selectivity of 1,8-cineole was 51.3%.

[0052] Example 5

[0053] A synthesis process for 1,8-cineole comprises the following steps:

[0054] 200g of α-terpineol (98%; purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) was added to the autoclave, the autoclave was warming up to 60°C, and then the catalyst prepared by Example 2 of 10g was added thereto with stirring. After completion of the addition, carbon dioxide (99.8%; purchased from Shanghai Canghai Industrial Gas Co., Ltd.) was charged into the autoclave, and the pressure in the autoclave reached 25Mpa. The autoclave was stirred and warmed to 90°C, and the reaction was stirred at a constant temperature for 10h. After completion of the reaction, the pressure was released and the catalyst was separated by an external magnetic field. The residual product was analyzed and detected by gas chromatograph (Agilent-7890-GC) and gas chromatography-mass spectrometry (Shimadzu, Japan) to determine the composition of the product. The conversion of α-terpineol was 96.1%, and the selectivity of 1,8-cineole was 52.5%.

[0055] Example 6

[0056] A synthesis process for 1,8-cineole comprises the following steps:

[0057] 200g of α-terpineol (98%; purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) was added to the autoclave, the autoclave was warming up to 65°C, and then the catalyst prepared by Example 3 of 10g was stirred and added thereto. After completion of the addition, carbon dioxide (99.8%; purchased from Shanghai Canghai Industrial Gas Co., Ltd.) was charged into the autoclave again, and the pressure in the autoclave reached 25Mpa. The autoclave was stirred and warmed to 100°C, and the reaction was stirred at a constant temperature for 12h. After completion of the reaction, the pressure was released and the catalyst was separated by an external magnetic field. The residual product was analyzed and detected by gas chromatograph (Agilent-7890-GC) and gas chromatography-mass spectrometry (Shimadzu, Japan) to determine the composition of the product. The conversion of α-terpineol was 95.7%, and the selectivity of 1,8-cineole was 52.2%.

[0058] Comparative Example 3

[0059] Comparative Example 3 is a control group of Example 5, wherein the catalyst prepared in Example 2 in Example 5 is replaced by the catalyst in Comparative Example 1, and the remaining raw materials, raw material amounts, process steps and parameters remain unchanged, and finally a product is obtained. The composition of the product is analyzed and detected by gas chromatograph (Agilent-7890-GC) and gas chromatography-mass spectrometry (Shimadzu, Japan), wherein the conversion rate of α-terpineol is 61.3%, and the selectivity of 1,8-cineole is 33.5%.

[0060] Comparative Example 4

[0061] Comparative Example 4 is a control group of Example 5, wherein the catalyst prepared in Example 2 in Example 5 is replaced by the catalyst in Comparative Example 2, and the remaining raw materials, raw material amounts, process steps and parameters remain unchanged, and finally a product is obtained. The composition of the product is analyzed and detected by gas chromatograph (Agilent-7890-GC) and gas chromatography-mass spectrometry (Shimadzu, Japan), wherein the conversion rate of α-terpineol is 52.7%, and the selectivity of 1,8-cineole is 28.4%.

[0062] It should be noted that, in this document, terms such as "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0063] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A synthesis process for 1,8-cineole, characterized in that, The following steps are involved: α-terpineol is added to an autoclave, the autoclave is heated to 55-65° C., and a catalyst is added thereto with stirring. After the addition is complete, carbon dioxide is introduced into the autoclave until the pressure in the autoclave reaches 20-25 MPa. The autoclave is then heated to 80-100° C. with stirring and reacted at a constant temperature for 8-12 hours. After the reaction is complete, the pressure is released and the material is discharged. The catalyst is separated using an external magnetic field, and the remaining product, 1,8-cineole, is obtained. The catalyst is prepared by the following steps: Add cobalt nitrate hexahydrate and ferric nitrate nonahydrate to the hydrochloric acid solution, after the addition is completed, place the system in a water bath at 70-80° C. and stir at a constant temperature for 1-2 hours, after the stirring is completed, add citric acid thereto, after the addition is completed, continue to stir in a water bath at a constant temperature for 30-50 minutes, after the addition is completed, add titanium silicon molecular sieve thereto with stirring, continue to stir in a water bath at a constant temperature for 2-3 hours, after the completion, place in a constant temperature drying oven at 40-50° C. and dry to constant weight to obtain a magnetic carrier, place the magnetic carrier in a muffle furnace at 500-550° C. and roast for 2 hours, after the roasting is completed, obtain a titanium silicon magnetic carrier; A titanium silicate magnetic carrier was added to a 75% by mass ethanol aqueous solution with stirring, and ultrasonic stirring was performed for 30 minutes. 3-aminopropyltriethoxysilane was then added thereto with stirring, and the mixture was stirred at room temperature for 3 hours. The solid component was collected with a magnet, and the solid component was washed with deionized water 3 to 5 times, and then dried at room temperature for 12 hours to obtain an amino magnetic carrier. Add the amino magnetic carrier and phosphotungstic acid to dichloromethane with stirring. After the addition is completed, heat to 80°C and reflux for 12 hours. After completion, remove the solvent under reduced pressure, wash the remaining solute with ether 3 to 5 times, and then place it in a vacuum drying oven at 60 to 70°C and dry it for 12 hours. After drying, cool it to room temperature to obtain a catalyst.

2. A synthesis process for 1,8-cineole according to claim 1, characterized in that, The usage ratio of the α-terpineol and the catalyst is 200g:7-10g.

3. A synthesis process for 1,8-cineole according to claim 1, characterized in that, The usage ratio of the dichloromethane, the amino magnetic carrier and the phosphotungstic acid is 100 mL: 2 g: 11.5-14.4 g.

4. A synthesis process for 1,8-cineole according to claim 1, characterized in that, The molar concentration of the hydrochloric acid solution is 0.5 mol / L.

5. A synthesis process for 1,8-cineole according to claim 1, characterized in that, The molar concentration of the citric acid is equal to the sum of the molar concentrations of the metal ions in the mixed solution.

6. A synthesis process for 1,8-cineole according to claim 1, characterized in that, The usage ratio of the hydrochloric acid solution, cobalt nitrate hexahydrate, ferric nitrate nonahydrate and titanium silicon molecular sieve is 500 mL:14.5 g:40.4 g:50 g.