Methods for synthesizing methylindane and tetrahydronaphthalene from cyclopentanone

Abstract

This invention relates to a method for synthesizing methylindane and tetrahydronaphthalene from the biomass platform compound cyclopentanone. Using cyclopentanone as a raw material, the method involves a fixed-bed continuous reactor where, under the action of a molecular sieve catalyst, cyclopentanone is converted in one step into the target products methylindane and tetrahydronaphthalene. This invention features a simple process route, is environmentally friendly, and utilizes inexpensive and readily available catalysts, providing a novel approach for the synthesis of methylindane and tetrahydronaphthalene from cyclopentanone.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for synthesizing methylindane and tetrahydronaphthalene from cyclopentanone BACKGROUND

[0002] Methylindane and tetrahydronaphthalene are very important chemicals, which are widely used in chemical, pharmaceutical and rubber industries, and are also important additives for improving the thermal stability and shock resistance of aviation fuel. Currently, tetrahydronaphthalene is mainly prepared by catalytic hydrogenation of naphthalene, which is the most abundant aromatic compound in coal tar. CN108059581A provides a method for preparing tetrahydronaphthalene by hydrogenation of naphthalene, in which a mixture of naphthalene and benzene is hydrogenated at 240-320℃, and the product is hydrogenated again, then the twice hydrogenated product is cooled, flashed and separated in sequence to obtain tetrahydronaphthalene product. CN108325517A discloses a method for producing tetrahydronaphthalene from industrial naphthalene containing more impurities, in which the naphthalene is hydrogenated in the presence of sulfided Ni x Al y Si z Mo 10 The conversion rate of naphthalene is higher than 95% and the selectivity of tetrahydronaphthalene tends to 100% under the optimal conditions of using composite metal as catalyst. In addition, it is found in CN109092315A that the oxidized NiMo / Al2O3 catalyst also has significant effect on the selective hydrogenation of naphthalene to prepare tetrahydronaphthalene. Methylindane is usually obtained by further isomerization of tetrahydronaphthalene, and there is a large amount of methylindane in the reaction product of catalytic cracking of tetrahydronaphthalene. Although the above methods are commonly used, the raw materials are non-renewable, and the yield of tetrahydronaphthalene and methylindane obtained from fossil energy is low, and the process involves rectification separation process or catalyst preparation is complicated, the process equipment is complex, and the energy consumption is high. Therefore, it is necessary to develop green and renewable production technology of tetrahydronaphthalene and methylindane in the long run.

[0003] To meet the needs of sustainable development and environmental protection, the catalytic conversion of renewable, abundant, and carbon-neutral biomass into high-quality fuels and high-value-added chemicals has attracted widespread attention. For example, CN113968776A discloses a method for preparing cyclopentanone from biomass feedstock. This system, under certain reaction conditions, can prepare cyclopentanone in high yield from hemicellulose, xylan, xylose, and arabinose in a single step. Furthermore, CN107814676A provides a novel route for synthesizing tetrahydronaphthalene from cyclopentanone aldol condensation / hydrogenation to obtain cyclopentylcyclopentanone, cyclopentylcyclopentanone, cyclopentylcyclopentanol, or cyclopentylcyclopentanol. This route mainly includes the following steps: 1) hydrogenation of polycyclic ketones to polycyclic alcohols under the promotion of a metal catalyst; 2) dehydration isomerization of polycyclic alcohols to obtain octahydronaphthalene under acid catalysis; 3) dehydrogenation of octahydronaphthalene to prepare tetrahydronaphthalene under the action of a metal catalyst. The numerous steps make this method impractical for industrial application. To date, no literature has reported the direct preparation of tetrahydronaphthalene and methyl indanone from cyclopentanone. Summary of the Invention

[0004] The key technical problem to be solved by this invention is to provide a novel, simple, and efficient method for converting cyclopentanone into methyl indenhydride and tetrahydronaphthalene. This invention uses cyclopentanone as a raw material and synthesizes tetrahydronaphthalene and methyl indenhydride in one step via aldol condensation / rearrangement / aromatization reaction in a fixed-bed continuous reactor.

[0005] This invention is achieved through the following technical solution:

[0006] A method for synthesizing methyl indenhydride and tetrahydronaphthalene from cyclopentanone, the method being as follows: using cyclopentanone as a raw material, in a fixed-bed continuous reactor, under the action of a molecular sieve catalyst, cyclopentanone is converted into the target products methyl indenhydride and tetrahydronaphthalene in one step through a series of aldol condensation / rearrangement / aromatization reactions, thereby achieving the synthesis of methyl indenhydride and tetrahydronaphthalene.

[0007] The chemical structural formulas of the above-mentioned raw material cyclopentanone and the target products methylindanone and tetrahydronaphthalene are shown in Table 1.

[0008] Table 1 Structural formulas of the compounds

[0009]

[0010] Based on the above scheme, preferably, the molecular sieve catalyst includes one or more of H-ZSM-5, H-USY, HY, H-β, H-MOR, H-ZSM-35, H-MCM-22, H-ZSM-22 and H-ZSM-11.

[0011] Based on the above scheme, preferably, the molar silicon-to-aluminum ratio of the molecular sieve is 2-500, more preferably between 5-400, and even more preferably between 5-300.

[0012] Based on the above scheme, preferably, the reaction temperature in the fixed-bed reactor is 300-600℃, more preferably between 400-500℃, and even more preferably between 425-475℃.

[0013] Based on the above scheme, preferably, the reaction gas in the fixed-bed reactor is nitrogen, and the pressure is 0.0001-1 MPa, more preferably the reaction pressure is between 0.0001-0.8 MPa, and more preferably the reaction pressure is between 0.0001-0.5 MPa.

[0014] Based on the above scheme, preferably, the molar ratio of nitrogen to cyclopentanone in the fixed-bed reactor is 10-400:1, more preferably between 20-300:1, and even more preferably between 30-200:1.

[0015] Based on the above scheme, preferably, the space velocity of cyclopentanone in the fixed-bed reactor is 0.01-10 h⁻¹. -1 The preferred cyclopentanone time space velocity is 0.05-8 h⁻¹. -1 More preferably, cyclopentanone has a space velocity of 0.1-6 h⁻¹. -1 between.

[0016] The method described in this invention enables the direct synthesis of high-value-added methylindanone and tetrahydronaphthalene from the biomass platform compound cyclopentanone.

[0017] The beneficial effects of this invention are:

[0018] This invention presents a simple and convenient process route, enabling the one-step conversion of cyclopentanone into methylindane and tetrahydronaphthalene via a cascaded aldol condensation / rearrangement / aromatization reaction. This green and efficient new route provides a novel approach for the synthesis of methylindane and tetrahydronaphthalene from cyclopentanone. To date, there have been no reports on the synthesis of methylindane and tetrahydronaphthalene from cyclopentanone via aldol condensation / rearrangement / aromatization.

[0019] The catalyst of this invention is inexpensive and readily available, the reaction conditions are mild, the conversion rate of cyclopentanone is over 90%, the total selectivity of methylindanone and tetrahydronaphthalene is over 70%, and the catalytic performance is good.

[0020] This invention employs a fixed-bed continuous flow reactor, which, under the action of a molecular sieve catalyst, can convert cyclopentanone into methyl indenman and tetrahydronaphthalene in one step. The process route is simple, environmentally friendly, and the catalyst is inexpensive and readily available. It has the advantages of high operability, low energy consumption, and environmental friendliness, and can be used for actual industrial production. Attached Figure Description

[0021] Figure 1 Gas chromatograms of the products synthesized from cyclopentanone into methyl indanone and tetrahydronaphthalene.

[0022] Figure 2 Mass spectra of the target products methylindane and tetrahydronaphthalene. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0024] The experiment to prepare methylindanone and tetrahydronaphthalene from cyclopentanone was conducted in a fixed-bed reactor. A pure cyclopentanone solution was pumped in at a certain rate using a liquid chromatography pump. Molecular sieves were used as catalysts, and the reaction was carried out at a set temperature, nitrogen pressure, nitrogen to cyclopentanone molar ratio, and cyclopentanone hourly space velocity.

[0025] Examples 1-33

[0026] The activity of different catalysts in the synthesis of methylindane and tetrahydronaphthalene from cyclopentanone was investigated: 0.6 g of one or more of the following catalysts was uniformly mixed with 2 g of quartz sand (40-70 mesh) and packed into a fixed-bed continuous reactor. The temperature was increased to 450 °C at a rate of 10 °C / min, and then the reaction was carried out under nitrogen pressure of 0.01 MPa, a nitrogen to cyclopentanone molar ratio of 40:1, and a cyclopentanone time space velocity of 0.4 h⁻¹. -1 The reaction was carried out under the following conditions, and the experimental results are shown in Table 2.

[0027] Table 2. Reactivity of different molecular sieve catalysts for the synthesis of methylindene and tetrahydronaphthalene from cyclopentanone.

[0028]

[0029]

[0030] The data in Table 2 show that the molecular sieve catalysts listed in the table all have good effects on the synthesis of methylindane and tetrahydronaphthalene from cyclopentanone. The silica-alumina ratio of different molecular sieves also has a certain influence on the conversion rate of cyclopentanone and the total selectivity of methylindane and tetrahydronaphthalene. Under the action of the H-ZSM-5(160) molecular sieve catalyst, complete conversion of cyclopentanone can be achieved, and the total selectivity of the target products methylindane and tetrahydronaphthalene reaches 86%.

[0031] Examples 34-43

[0032] The effect of reaction temperature on the reaction activity of cyclopentanone in the synthesis of methylindene and tetrahydronaphthalene was investigated: 0.6 g of the H-ZSM-5 (160) molecular sieve catalyst used in Example 6 was uniformly mixed with 2 g of quartz sand (40-70 mesh) and packed into a fixed-bed continuous reactor. The temperature was increased to the investigated temperature at a rate of 10 °C / min. Then, the reaction was carried out under nitrogen pressure of 0.01 MPa, a nitrogen to cyclopentanone molar ratio of 40:1, and a cyclopentanone time space velocity of 0.4 h⁻¹. -1 The reaction was carried out under the specified conditions, and the experimental results are shown in Table 3.

[0033] Table 3. Effect of reaction temperature on the reactivity of cyclopentanone in the synthesis of methylindenam and tetrahydronaphthalene.

[0034]

[0035]

[0036] The data in Table 3 show that, under the same conditions, the reaction temperature has a significant impact on the conversion rate of cyclopentanone and the total selectivity of methylindanone and tetrahydronaphthalene. Increasing the reaction temperature will improve the reaction activity to some extent, but excessively high temperatures will decrease the total selectivity of methylindanone and tetrahydronaphthalene.

[0037] Examples 44-49

[0038] The effect of nitrogen pressure on the reactivity of cyclopentanone in the synthesis of methylindane and tetrahydronaphthalene: 0.6 g of the H-ZSM-5(160) molecular sieve catalyst used in the above examples was uniformly mixed with 2 g of quartz sand (40-70 mesh) and packed into a fixed-bed continuous reactor. The temperature was increased to 425 °C at a rate of 10 °C / min, and the molar ratio of nitrogen to cyclopentanone was controlled at 40:1, with a cyclopentanone hourly space velocity of 0.4 h⁻¹. -1 The reaction was then carried out under different nitrogen pressures, and the experimental results are shown in Table 4.

[0039] Table 4. Effect of nitrogen pressure on the reactivity of cyclopentanone in the synthesis of methylindenam and tetrahydronaphthalene.

[0040]

[0041] The data in Table 4 show that, under the same conditions, nitrogen pressure has no effect on the conversion rate of cyclopentanone, but it has a significant impact on the overall selectivity of methylindanone and tetrahydronaphthalene. As the nitrogen pressure gradually decreases, the overall selectivity of methylindanone and tetrahydronaphthalene gradually increases and then remains constant.

[0042] Examples 50-57

[0043] The effect of the molar ratio of nitrogen to cyclopentanone on the reactivity of cyclopentanone in the synthesis of methyl indenhydride and tetrahydronaphthalene: 0.6 g of the H-ZSM-5(160) molecular sieve catalyst used in the above examples was uniformly mixed with 2 g of quartz sand (40-70 mesh) and packed into a fixed-bed continuous reactor. The temperature was increased to 425 °C at a rate of 10 °C / min, while the nitrogen pressure was controlled at 0.001 and the cyclopentanone hourly space velocity was 0.4 h⁻¹. -1 The reaction was then carried out at different molar ratios of nitrogen to cyclopentanone, and the experimental results are shown in Table 5.

[0044] Table 5. Effect of the molar ratio of nitrogen to cyclopentanone on the reactivity of cyclopentanone in the synthesis of methylindanone and tetrahydronaphthalene.

[0045]

[0046] As can be seen from the data in Table 5, under the same conditions, the molar ratio of nitrogen to cyclopentanone has little effect on the conversion of cyclopentanone to methylindanone and tetrahydronaphthalene.

[0047] Examples 58-68

[0048] The effect of cyclopentanone hourly space velocity on the reactivity of cyclopentanone in the synthesis of methyl indenman and tetrahydronaphthalene: A certain amount of H-ZSM-5(160) molecular sieve catalyst used in the above examples was uniformly mixed with 2g of quartz sand (40-70 mesh) and packed into a fixed-bed continuous reactor. The temperature was increased to 425℃ at a rate of 10℃ / min, the nitrogen pressure was controlled at 0.001, and the molar ratio of nitrogen to cyclopentanone was 30:1. The reaction was then carried out at different cyclopentanone hourly space velocities. The experimental results are shown in Table 6.

[0049] Table 6. Effect of space velocity on the reaction activity of cyclopentanone in the synthesis of methylindenam and tetrahydronaphthalene.

[0050]

[0051] The data in Table 6 show that, under the same conditions, the space velocity (WHV) of cyclopentanone has a significant impact on the conversion of cyclopentanone to methylindenam and tetrahydronaphthalene. Increasing the WHV of cyclopentanone will improve the overall selectivity of methylindenam and tetrahydronaphthalene to some extent, but excessively high WHV of cyclopentanone will reduce the reactivity, and both the conversion rate of cyclopentanone and the overall selectivity of methylindenam and tetrahydronaphthalene will be significantly reduced.

Claims

1. Process for the synthesis of methylindane and tetrahydronaphthalene from cyclopentanone, characterized in that, The method is as follows: taking cyclopentanone as raw material, cyclopentanone is converted into methylindane and tetrahydronaphthalene in one step under the action of molecular sieve catalyst in a fixed bed continuous reactor; The molecular sieve catalyst is one or more of H-ZSM-5, H-USY, H-Y, H-beta, H-MOR, H-ZSM-35, H-MCM-22, H-ZSM-22 and H-ZSM-11; The reaction temperature in the fixed bed reactor is 300-600 DEG C; The reaction gas in the fixed bed reactor is nitrogen, and the pressure is 0.0001-1 MPa; The molar ratio of nitrogen to cyclopentanone in the fixed bed reactor is 10-400:

1.

2. The method of claim 1, wherein: The molar silicon aluminum ratio of the molecular sieve is 2-500.

3. The method of claim 2, wherein: The molar silicon aluminum ratio of the molecular sieve is 5-400.

4. The method of claim 3, wherein: The molar silicon aluminum ratio of the molecular sieve is 5-300.

5. The method of claim 1, wherein: The reaction temperature in the fixed bed reactor is 400-500 DEG C.

6. The method of claim 5, wherein: The reaction temperature in the fixed bed reactor is 425-475 DEG C.

7. The method of claim 1, wherein: The reaction pressure in the fixed bed reactor is 0.0001-0.8 MPa.

8. The method of claim 7, wherein: The reaction pressure in the fixed bed reactor is 0.0001-0.5 MPa.

9. The method of claim 5, wherein: The molar ratio of nitrogen to cyclopentanone in the fixed bed reactor is 20-300:

1.

10. The method of claim 9, wherein: The molar ratio of nitrogen to cyclopentanone in the fixed bed reactor is 30-200:

1.

11. The method of claim 1, wherein: The space time velocity of cyclopentanone in the fixed bed reactor is 0.01-10 h -1 .

12. The method of claim 11, wherein: The space time velocity of cyclopentanone in the fixed bed reactor is 0.05-8 h -1 .

13. The method of claim 12, wherein: The space time velocity of cyclopentanone in the fixed bed reactor is 0.1-6 h -1 .

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