A preparation method of tetrahydropentamethylindane

Abstract

The present invention discloses a method for preparing tetrahydropentamethylindane. The method comprises the following steps: 1) introducing 1,1,2,3,3-pentamethylindane, a catalyst, a solvent, and hydrogen into a microchannel reactor; under the action of the catalyst, the 1,1,2,3,3-pentamethylindane undergoes a selective hydrogenation reaction to obtain a first hydrogenation reaction liquid; and 2) subjecting the first hydrogenation reaction liquid to a second hydrogenation reaction to obtain a second hydrogenation reaction liquid. The hydrogen used in step 2) is supplemented with 10-2000 ppm of carbon monoxide gas. The method achieves high selectivity and high yield for tetrahydropentamethylindane, while the selectivity of over-hydrogenated products, such as hexahydropentamethylindane, is reduced, thereby achieving efficient conversion of 1,1,2,3,3-pentamethylindane.

Description

Technical Field

[0001] The present invention relates to the field of chemical technology synthesis of musk-type fragrances, and in particular to a method for preparing tetrahydropentamethylindane, a cashmeranone intermediate. Background Art

[0002] Cashmeran, also known as indanone, has a rich, sweet, musky aroma with floral and ambergris notes. Cashmeran is industrially produced using pentamethylindane as a raw material, using Raney nickel as a catalyst. This is followed by selective hydrogenation to produce tetrahydropentamethylindane, which is then oxidized to produce cashmeranone.

[0003] The general reaction formula is:

[0004]

[0005] This solution involves high hydrogen pressure and temperature, posing safety risks. Furthermore, the oxidation step uses potassium dichromate as a catalyst, making the treatment of chromium-containing waste expensive and difficult, placing significant pressure on environmental protection.

[0006] US3773836A reports that the hydrogenation of 1,1,2,3,3-pentamethylindane under Raney nickel catalysis yields three products: dihydropentamethylindane, tetrahydropentamethylindane, and hexahydropentamethylindane. The hexahydro product accounts for a higher proportion than the tetrahydro product, while the target product, tetrahydropentamethylindane, accounts for less than 30%. Gu Yuncui reports (Synthesis of Cashmeranone, Flavors, Fragrances, and Cosmetics Supplement, August 2013, pp. 32-35) that using Pd / C as a catalyst for selective hydrogenation, after optimizing the conditions, the selectivity for tetrahydropentamethylindane was increased to 55% to 60%. Because the degree of hydrogenation of the pentamethylindane benzene ring is difficult to control and can easily lead to over-hydrogenation, improving the selectivity for tetrahydropentamethylindane is a challenge in this step.

[0007]

[0008] CN113929564A reports a process using 1,1,2,3,3-pentamethylindane as a starting material, hydrogenated over a palladium catalyst to produce 1,1,2,3,3-pentamethyl-4,5,6,7-tetrahydroindane. Oxygen or an oxygen-air mixture is then introduced into the 1,1,2,3,3-pentamethyl-4,5,6,7-tetrahydroindane, where it is oxidized to cashmerone using zinc nitrate and tert-butyl peroxide as catalysts. In addition to cashmerone, epoxyindanone is also produced as a byproduct, which also has a sweet and strong musky aroma. The primary product of the oxidation step in this scheme is a cashmerone mixture with a purity of approximately 57%. No chromium-containing oxidant is used, but the product yield still needs to be improved. Summary of the Invention

[0009] The invention provides a method for preparing tetrahydropentamethylindane, which solves the problem of low yield in preparing cashmeranone using 1,1,2,3,3-pentamethylindane as a raw material, in particular the problem of low selectivity of tetrahydropentamethylindane obtained by hydrogenating 1,1,2,3,3-pentamethylindane.

[0010] The present invention adopts the following technical solutions:

[0011] A method for preparing tetrahydropentamethylindane comprises the following steps:

[0012] 1) introducing 1,1,2,3,3-pentamethylindane, a catalyst, a solvent, and hydrogen into a microchannel reactor; and in the presence of the catalyst, selectively hydrogenating the 1,1,2,3,3-pentamethylindane to obtain a first hydrogenation reaction liquid;

[0013] 2) The first hydrogenation reaction liquid is subjected to a second hydrogenation reaction to obtain a second hydrogenation reaction liquid.

[0014] In the present invention, the microchannel reactor used in step 1) includes a feed pump, a preheating pipeline, a microreactor, and a delay pipeline.

[0015] In the present invention, in step 1), 1,1,2,3,3-pentamethylindane and the hydrogen-containing catalyst solution enter the preheating pipeline via a feed pump, and are then pumped into the microreactor separately. After being fully mixed and briefly stopped in the microreactor, they enter the delay pipeline section. The reaction liquid is depressurized by the pressure relief valve after the delay pipeline section and cooled before entering the first hydrogenation reaction liquid storage tank. After the reaction liquid is preheated in the preheating pipeline, the reaction liquid temperature is 60-90°C, the reaction temperature of the reaction liquid in the microreactor is 80-120°C, and the reaction temperature of the reaction liquid in the delay pipeline is 80-120°C. The residence time of the entire reaction process is 1-10 minutes, preferably 2-5 minutes.

[0016] In the present invention, the microchannel reactor in step 1) has two feed ports: a 1,1,2,3,3-pentamethylindane feed port and a hydrogen-containing catalyst solution feed port. The catalyst, solvent, and hydrogen are premixed in a tank reactor before entering the microchannel reactor. The two streams are mixed within the microchannel reactor and rapidly undergo a selective hydrogenation reaction to produce a first hydrogenation reaction solution.

[0017] In the present invention, the hydrogen pressure in the autoclave reactor in step 1) is 0.1 MPa to 5.0 MPa (gauge pressure), preferably 1.0 MPa to 3.0 MPa (gauge pressure).

[0018] In step 1) of the present invention, the solvent is selected from one or more of inert aliphatic alkanes, halogenated hydrocarbons, ethers, and alcohols that do not react with the raw materials, for example, one or more of n-heptane, 1,2-dichloroethane, tetrahydrofuran, ethanol, etc., preferably n-heptane and / or ethanol.

[0019] In step 1) of the present invention, the amount of the solvent used is 0.5 to 30 times, preferably 1 to 10 times, the mass of 1,1,2,3,3-pentamethylindane.

[0020] As a preferred embodiment, in the present invention, the catalyst in step 1) is a homogeneous hydrogenation catalyst. Preferably, it is a homogeneous catalyst obtained by complexing ruthenium, rhodium, iridium and a phosphine ligand, such as one or more of triphenylphosphine chlororuthenium (Ph3P)3RuClH, triphenylphosphine carbonyl hydride iridium (Ph3P)3(CO)IrH, and triphenylphosphine rhodium chloride (Ph3P)3RhCl, preferably triphenylphosphine rhodium chloride (Ph3P)3RhCl.

[0021] As a preferred solution, in step 1), the amount of catalyst used is 0.0005 mol‰ to 0.05 mol‰, preferably 0.001 mol‰ to 0.01 mol‰, of the molar amount of 1,1,2,3,3-pentamethylindane, calculated as the molar amount of the metal element.

[0022] The first hydrogenation reaction liquid of the present invention mainly comprises dihydropentamethylindane and tetrahydropentamethylindane, wherein the dihydropentamethylindane accounts for 5 to 95 wt% and the tetrahydropentamethylindane accounts for 5 to 95 wt%.

[0023] As a preferred solution, in the present invention, after step 1) is completed, the homogeneous hydrogenation catalyst can be removed from the first hydrogenation reaction liquid by resin adsorption or distillation.

[0024] In the present invention, the second hydrogenation catalyst in step 2) is a palladium / calcium carbonate (Lindlar) catalyst.

[0025] As a preferred solution, in step 2), the amount of catalyst used is 0.5% to 2% of the mass of the first hydrogenation reaction liquid.

[0026] In the present invention, 10-2000 ppm of carbon monoxide gas is added to the hydrogen used in step 2).

[0027] As a preferred solution, in step 2), the hydrogenation pressure (gauge pressure) is 0.5 to 3.0 MPa, preferably 1.0 to 2.0 MPa.

[0028] As a preferred solution, in step 2), the reaction temperature is 40-90° C. and the reaction time is 1-12 h.

[0029] In the present invention, the second hydrogenation reaction liquid in step 2) can be distilled or rectified to remove the solvent to purify the high-purity tetrahydropentamethylindane, or the solvent cannot be removed before entering the subsequent oxidation process.

[0030] The second hydrogenation reaction liquid of the present invention is mainly tetrahydropentamethylindane.

[0031] The positive effect of the present invention is that tetrahydropentamethylindane is prepared by step-by-step selective hydrogenation, which solves the disadvantage of low selectivity of existing process technologies, reduces the content of over-hydrogenation products such as hexahydropentamethylindane, and realizes efficient conversion and utilization of 1,1,2,3,3-pentamethylindane. DETAILED DESCRIPTION

[0032] The following examples will further illustrate the process provided by the present invention, but the present invention is not limited to the listed examples, and should also include any other known changes within the scope of the rights claimed by the present invention.

[0033] Analytical methods:

[0034] Gas chromatograph: Agilent 7820A, column HP-5 (30 m × 320 μm × 0.25 μm), inlet temperature: 150°C; split ratio: 50:1; carrier gas flow rate: 1.5 ml / min; heating program: 40°C, hold for 1 min, increase at 10°C / min to 90°C, hold for 0 min, then increase at 5°C / min to 160°C, hold for 0 min, then increase at 30°C / min to 280°C, hold for 6 min. Detector temperature: 280°C.

[0035] Microreactor model: CPMM-R300-so purchased from Dalian Weikai Chemical Co., Ltd.

[0036] Palladium-calcium carbonate catalyst: 5% Pd-5% Pb palladium-calcium carbonate catalyst, Sinoco Technology Co., Ltd.;

[0037] 1,1,2,3,3-Pentamethylindane: Purity ≥98% J&K Technology Co., Ltd.

[0038] Triphenylphosphine rhodium chloride: purity ≥98%, Beijing Yinuokai Technology Co., Ltd.

[0039] Chlorohydrotriphenylphosphine ruthenium: purity ≥98%, Beijing Yinuokai Technology Co., Ltd.

[0040] Carbonyl triphenylphosphine iridium complex: purity ≥98%, Beijing Yinuokai Technology Co., Ltd.

[0041] Example 1

[0042] First, 9.83 mg of triphenylphosphine rhodium chloride and 2000 g of ethanol were added to the autoclave. After stirring, the mixture was replaced with 2.0 MPa nitrogen six times, and then 2.0 MPa of hydrogen was introduced and maintained at 2.0 MPa. The reaction liquid temperature was controlled at 60°C. A restrictive orifice plate and flowmeter were installed at the bottom of the autoclave. The mixed liquid stream was fed into the microchannel reactor at a controlled rate of 25 g / min via the flowmeter.

[0043] The microreactor preheating tube was 1.0 m long and had an inner diameter of 1 mm. The reaction liquid was preheated to 80°C in the preheating line. After passing through the microreactor, the outlet temperature reached 120°C. The reaction continued at 120°C in the delay line, which was 15 m long and had an inner diameter of 4 mm. The raw material, 1,1,2,3,3-pentamethylindane, was fed through the preheating line at a rate of 25 g / min. The 1,1,2,3,3-pentamethylindane and the catalyst solution were thoroughly mixed in the microreactor and passed through the delay line (pressure drop to 0.15 MPa). Sampling was taken after the system stabilized. The raw material conversion was 99.80%, with selectivities for dihydropentamethylindane of 73.21% and tetrahydropentamethylindane of 25.34%.

[0044] After removing the rhodium catalyst by resin adsorption, 200 g of the first hydrogenation reaction liquid was added to an autoclave. 2 g of palladium-calcium carbonate catalyst was added to the autoclave. The autoclave was sealed and purged with nitrogen three times. After nitrogen pressure was increased to 2.0 MPa to confirm that the autoclave was well sealed, the nitrogen was vented and purged with hydrogen containing 500 ppm of carbon monoxide six times. The stirring paddle was turned on and the hydrogen pressure containing 500 ppm of carbon monoxide was maintained at 2.0 MPa. The temperature in the reactor was maintained at 80° C. for 4 hours. After stopping stirring and venting the gas, the reaction liquid was analyzed by GC, revealing a feedstock conversion of 99.9%, a tetrahydropentamethylindane selectivity of 95.62%, and a hexahydropentamethylindane selectivity of 2.91%.

[0045] Example 2

[0046] First, 11.80 mg of triphenylphosphine rhodium chloride and 2000 g of ethanol were added to the autoclave. After stirring, the mixture was replaced with 3.0 MPa nitrogen six times, and then 3.0 MPa of hydrogen was introduced and maintained at 3.0 MPa. The reaction liquid temperature was controlled at 60°C. A restrictive orifice plate and flowmeter were installed at the bottom of the autoclave. The mixed liquid stream was fed into the microchannel reactor at a controlled rate of 30 g / min via the flowmeter.

[0047] The microreactor's preheating tube was 1.0 m long and had an inner diameter of 1 mm. The reaction liquid was preheated to 70°C in the preheating line. After passing through the microreactor, the outlet temperature reached 100°C, where it continued to react at 100°C through a 15 m long, 4 mm inner diameter delay line. The raw material, 1,1,2,3,3-pentamethylindane, was fed through the preheating line at a rate of 6 g / min. The 1,1,2,3,3-pentamethylindane and catalyst solution were thoroughly mixed within the microreactor and then passed through the delay line (pressure drop to 0.15 MPa). Sampling was performed after the system stabilized. The raw material conversion was 99.65%, with selectivities for dihydropentamethylindane of 61.34% and tetrahydropentamethylindane of 37.28%.

[0048] After removing the rhodium catalyst by resin adsorption, 200g of the first hydrogenation reaction liquid was added to an autoclave. 4g of palladium-calcium carbonate catalyst was added to the autoclave. The autoclave was sealed and purged with nitrogen three times. After nitrogen pressure was increased to 1.0 MPa to confirm that the autoclave was well sealed, the nitrogen was vented and purged with hydrogen containing 1000ppm of carbon monoxide six times. The stirring paddle was turned on and the hydrogen pressure containing 1000ppm of carbon monoxide was maintained at 1.0MPa. The temperature in the reactor was maintained at 70°C for 6h. After stopping stirring and venting the gas, the reaction liquid was analyzed by GC, showing a feedstock conversion of 99.52%, a tetrahydropentamethylindane selectivity of 96.13%, and a hexahydropentamethylindane selectivity of 2.36%.

[0049] Example 3

[0050] First, 98.34 mg of triphenylphosphine rhodium chloride and 2000 g of n-heptane were added to the autoclave. After stirring, the atmosphere was replaced with 5.0 MPa nitrogen six times, and then 5.0 MPa of hydrogen was introduced, maintaining the hydrogen pressure at 5.0 MPa. The reaction liquid temperature was controlled at 60°C. A restrictive orifice plate and flowmeter were installed at the bottom of the autoclave. The mixed liquid stream was fed into the microchannel reactor at a controlled feed rate of 64 g / min via the flowmeter.

[0051] The microreactor preheating tube was 1.0 m long and had an inner diameter of 1 mm. The reaction liquid was preheated to 60°C in the preheating line. After passing through the microreactor, the outlet temperature reached 80°C. The reaction continued at 80°C in the delay line, which was 15 m long and had an inner diameter of 4 mm. The raw material, 1,1,2,3,3-pentamethylindane, was fed through the preheating line at a rate of 8 g / min. The 1,1,2,3,3-pentamethylindane and the catalyst solution were thoroughly mixed in the microreactor and passed through the delay line (pressure drop to 0.15 MPa). Sampling was taken after the system stabilized. The raw material conversion was 98.12%, with selectivities of 83.37% for dihydropentamethylindane and 15.37% for tetrahydropentamethylindane.

[0052] After removing the rhodium catalyst by resin adsorption, 200 g of the first hydrogenation reaction liquid was added to an autoclave. 3 g of palladium-calcium carbonate catalyst was added to the autoclave. The autoclave was sealed and purged with nitrogen three times. After nitrogen pressure was increased to 3.0 MPa to confirm that the autoclave was properly sealed, the nitrogen was vented and purged six times with hydrogen containing 2000 ppm of carbon monoxide. The stirring paddle was turned on and the hydrogen pressure containing 2000 ppm of carbon monoxide was maintained at 3.0 MPa. The temperature in the reactor was maintained at 90° C. for 1 hour. After stopping stirring and venting the gas, the reaction liquid was analyzed by GC, revealing a feedstock conversion of 98.17%, a tetrahydropentamethylindane selectivity of 96.22%, and a hexahydropentamethylindane selectivity of 2.14%.

[0053] Example 4

[0054] First, 507.14 mg of triphenylphosphine ruthenium chloride and 2000 g of ethanol were added to the autoclave. After stirring, the atmosphere was replaced with 1.0 MPa nitrogen six times, and then 1.0 MPa hydrogen was introduced, maintaining the hydrogen pressure at 1.0 MPa. The reaction liquid temperature was controlled at 60°C. A restrictive orifice plate and flowmeter were installed at the bottom of the autoclave. After mixing, the liquid stream was fed into the microchannel reactor at a controlled rate of 60 g / min via the flowmeter.

[0055] The microreactor preheating tube was 1.0 m long and had an inner diameter of 1 mm. The reaction liquid was preheated to 70°C in the preheating line. After passing through the microreactor, the outlet temperature reached 90°C. The reaction continued at 90°C in the delay line, which was 15 m long and had an inner diameter of 4 mm. The raw material, 1,1,2,3,3-pentamethylindane, was fed through the preheating line at a rate of 6 g / min. The 1,1,2,3,3-pentamethylindane and the catalyst solution were thoroughly mixed in the microreactor and passed through the delay line (pressure drop to 0.15 MPa). Sampling was taken after the system stabilized. The raw material conversion was 97.51%, with selectivities for dihydropentamethylindane of 86.75% and tetrahydropentamethylindane of 9.81%.

[0056] After removing the rhodium catalyst by resin adsorption, 200 g of the first hydrogenation reaction liquid was added to an autoclave. 4 g of palladium-calcium carbonate catalyst was added to the autoclave. The autoclave was sealed and purged with nitrogen three times. After nitrogen pressure was increased to 2.0 MPa to confirm that the autoclave was well sealed, the nitrogen was vented and purged six times with hydrogen containing 100 ppm of carbon monoxide. The stirring paddle was turned on and the hydrogen pressure containing 100 ppm of carbon monoxide was maintained at 2.0 MPa. The temperature in the reactor was maintained at 40° C. for 8 hours. After stopping stirring and venting the gas, the reaction liquid was analyzed by GC, revealing a feedstock conversion of 97.33%, a tetrahydropentamethylindane selectivity of 94.25%, and a hexahydropentamethylindane selectivity of 3.78%.

[0057] Example 5

[0058] First, 85.72 mg of triphenylphosphine iridium carbonyl hydrogenate and 2000 g of ethanol were added to the autoclave. After stirring, the mixture was replaced with 4.0 MPa nitrogen six times, and then hydrogen was introduced at 4.0 MPa, maintaining the hydrogen pressure at 4.0 MPa. The reaction liquid temperature was controlled at 60°C. A restrictive orifice plate and flowmeter were installed at the bottom of the autoclave. The mixed liquid stream was fed into the microchannel reactor at a controlled rate of 24 g / min via the flowmeter.

[0059] The microreactor's preheating tube was 1.0 m long and had an inner diameter of 1 mm. The reaction liquid was preheated to 90°C in the preheating line. After passing through the microreactor, the outlet temperature reached 110°C. The reaction continued at 110°C in the delay line, which was 15 m long and had an inner diameter of 4 mm. The raw material, 1,1,2,3,3-pentamethylindane, was fed through the preheating line at a rate of 4 g / min. The 1,1,2,3,3-pentamethylindane and the catalyst solution were thoroughly mixed in the microreactor and passed through the delay line (pressure drop to 0.15 MPa). Sampling was taken after the system stabilized. The raw material conversion was 97.06%, with selectivities for dihydropentamethylindane of 82.21% and tetrahydropentamethylindane of 13.54%.

[0060] 200g of the first hydrogenation reaction liquid was added to an autoclave after removing the rhodium catalyst through resin adsorption. 1g of palladium-calcium carbonate catalyst was added to the autoclave. The autoclave was sealed and purged with nitrogen three times. After nitrogen pressure was pressed to 1.0 MPa to confirm that the autoclave was well sealed, the nitrogen was vented and purged with hydrogen containing 10 ppm of carbon monoxide six times. The stirring paddle was turned on and the hydrogen pressure containing 10 ppm of carbon monoxide was maintained at 1.0 MPa. The temperature in the reactor was maintained at 60°C for 12 hours. After stopping stirring and venting the gas, the reaction liquid was analyzed by GC, showing a feedstock conversion of 96.91%, a tetrahydropentamethylindane selectivity of 92.85%, and a hexahydropentamethylindane selectivity of 5.31%.

[0061] Comparative Example 1

[0062] A first hydrogenation reaction liquid was prepared and a second hydrogenation was performed according to the method of Example 1, except that the hydrogen used in the second hydrogenation did not contain carbon monoxide. After stopping stirring and venting the gas, GC analysis of the reaction liquid showed a feed conversion rate of 99.80%, a tetrahydropentamethylindane selectivity of 47.63%, and a hexahydropentamethylindane selectivity of 51.34%.

[0063] Comparative Example 2

[0064] A first hydrogenation reaction liquid was prepared according to the method of Example 1, except that the temperature of the reaction liquid was raised to 120° C. after being preheated through the preheating pipeline, the outlet temperature of the reaction liquid reached 150° C. after passing through the microreactor, and the reaction was continued at 150° C. through the delay pipeline. The conversion rate of 1,1,2,3,3-pentamethylindane was 99.98%, the selectivity of dihydropentamethylindane was 13.60%, the selectivity of tetrahydropentamethylindane was 46.15%, and the selectivity of hexahydropentamethylindane was 35.72%.

[0065] Comparative Example 3

[0066] The first hydrogenation reaction liquid was prepared according to the method of Example 1, except that after the mixture of triphenylphosphine rhodium chloride and ethanol, the liquid phase was fed into the microchannel reactor at a controlled feed rate of 5 g / min via a flowmeter. The raw material, 1,1,2,3,3-pentamethylindane, was fed through the preheating line at a rate of 5 g / min. The conversion of 1,1,2,3,3-pentamethylindane was 99.91%, the selectivity for dihydropentamethylindane was 17.72%, the selectivity for tetrahydropentamethylindane was 51.34%, and the selectivity for hexahydropentamethylindane was 27.25%.

Claims

1. A method for preparing tetrahydropentamethylindane, comprising the following steps: 1) introducing 1,1,2,3,3-pentamethylindane, a catalyst, a solvent, and hydrogen into a microchannel reactor; and in the presence of the catalyst, selectively hydrogenating the 1,1,2,3,3-pentamethylindane to obtain a first hydrogenation reaction liquid; 2) performing a second hydrogenation reaction on the first hydrogenation reaction liquid to obtain a second hydrogenation reaction liquid; In the step 1), the catalyst is selected from one or more of triphenylphosphine ruthenium chloride, triphenylphosphine iridium carbonyl hydrogenation, and triphenylphosphine rhodium chloride; and in the step 2), the second hydrogenation catalyst is a palladium / calcium carbonate catalyst.

2. The method according to claim 1, characterized in that The microchannel reactor used in step 1) includes a feed pump, a preheating pipeline, a microreactor, and a delay pipeline; 1,1,2,3,3-pentamethylindane and a hydrogen-containing catalyst solution enter the preheating pipeline through the feed pump and are preheated to 60-90° C., and then are pumped into the microreactor respectively to react at 80-120° C., and after staying in the microreactor, enter the delay pipeline section to react at 80-120° C., and the reaction liquid is depressurized by the pressure relief valve after the delay pipeline section and cooled before entering the first hydrogenation reaction liquid storage tank; the residence time of the entire reaction process is 1-10 minutes.

3. The method according to claim 2, characterized in that The residence time of the entire reaction process is 2 to 5 minutes.

4. The method according to claim 1, wherein In the step 1), the hydrogen pressure in the microchannel reactor is 0.1 MPa to 5.0 MPa.

5. The method according to claim 1, wherein In the step 1), the hydrogen pressure in the microchannel reactor is 1.0 MPa to 3.0 MPa.

6. The method according to claim 1, characterized in that In step 1), the solvent is selected from one or more of inert aliphatic alkanes, halogenated hydrocarbons, ethers, and alcohols that do not react with the raw materials; and / or the amount of the solvent is 0.5 to 30 times the mass of 1,1,2,3,3-pentamethylindane.

7. The method according to claim 1, characterized in that In step 1), the solvent is selected from one or more of n-heptane, 1,2-dichloroethane, tetrahydrofuran, and ethanol; and / or the amount of the solvent is 1 to 10 times the mass of 1,1,2,3,3-pentamethylindane.

8. The method according to claim 1, characterized in that In the step 1), the amount of the catalyst used is 0.0005 mol‰ to 0.05 mol‰ of the molar amount of 1,1,2,3,3-pentamethylindane based on the molar amount of metal atoms.

9. The method according to claim 1, characterized in that In the step 1), the amount of the catalyst used is 0.001 mol‰ to 0.01 mol‰ of the molar amount of 1,1,2,3,3-pentamethylindane based on the molar amount of the metal atom.

10. The method according to claim 1, characterized in that The first hydrogenation reaction liquid contains 5 to 95 wt% of dihydropentamethylindane and 5 to 95 wt% of tetrahydropentamethylindane.

11. The method according to claim 1, wherein In the step 2), the amount of the second hydrogenation catalyst used is 0.5% to 2% of the mass of the first hydrogenation reaction liquid.

12. The method according to claim 1, characterized in that 10-2000 ppm of carbon monoxide gas is added to the hydrogen used in step 2).

13. The method according to claim 1, wherein In the step 2), the hydrogenation pressure is 0.5-3.0 MPa; the reaction temperature is 40-90° C., and the reaction time is 1-12 h.

14. The method according to claim 1, wherein In the step 2), the hydrogenation pressure is 1.0 to 2.0 MPa.

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