A method for continuously synthesizing a pendant tetrahydrodicyclopentadiene

Abstract

The present application relates to a kind of continuous synthesis of method of hanging tetrahydrodicyclopentadiene. Including: in fixed bed reactor, upper section is loaded with hydrogenation catalyst, middle is separated with inert material, lower section is loaded with isomerization catalyst, raw material dicyclopentadiene and reaction solvent are entered into fixed bed reactor from upper end, carry out hydrogenation and isomerization reaction, product flows out from lower end, obtain hanging tetrahydrodicyclopentadiene. This method can be realized in a fixed bed, namely dicyclopentadiene hydrogenation, isomerization reaction can be completed, so as to continuously prepare hanging tetrahydrodicyclopentadiene, simplify process flow, reduce the investment of device, while mild reaction condition, reaction product yield is higher, system can be long period stable operation.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for preparing hydrocarbons, in particular to a method for preparing Exo-THDCPD. BACKGROUND

[0002] Dicyclopentadiene (DCPD) is mainly derived from C5 fraction byproduct of ethylene production process and light benzene fraction byproduct of coal coking, which is a dimer of cyclopentadiene, an important chemical intermediate, widely used in synthesis of unsaturated polyester polymer, preparation of high-density aviation fuel, preparation of medical materials, etc. In the field of aviation fuel application, DCPD can be first converted into Endo-THDCPD by hydrogenation, and Endo-THDCPD can be further isomerized into Exo-THDCPD, the conversion process is shown in the following formula.

[0003]

[0004] Exo-THDCPD, also known as JP-10, can be used alone or in combination with other fuels, which has the advantages of large density (0.94 g / cm -3 ), low freezing point (-79℃), high volumetric heat value (39.4 MJ / L) and low toxicity, and has been widely used in many types of aircraft, such as "harpoon" missile, "hatchet" missile, etc. The common DCPD hydrogenation process is mainly completed by traditional hydrogenation catalyst or Raney nickel catalyst, and the isomerization process is mainly carried out intermittently by using high-toxicity and high-pollution AlCl3 as catalyst, which cannot realize continuous production, so that the yield of Exo-THDCPD is low and the cost is high, which limits its large-scale application. For some other patents such as CN 101244978A, the method using solid inorganic acid as isomerization catalyst often needs two solid bed reactors to load hydrogenation catalyst and isomerization catalyst, which has large device investment, high operation cost and complex process flow. SUMMARY

[0005] The present application aims at the problems of high device investment and complex process flow in the process of preparing Exo-THDCPD by two-step method of hydrogenation and isomerization of DCPD, and provides a method for continuously synthesizing Exo-THDCPD in one fixed bed reactor.

[0006] A method for continuously synthesizing a hanging tetrahydrodicyclopentadiene, comprising: in a fixed bed reactor, a hydrogenation catalyst is loaded in the upper section, an inert material is used to separate the middle section, an isomerization catalyst is loaded in the lower section, a raw material of dicyclopentadiene and a reaction solvent are fed into the fixed bed reactor from the upper end, hydrogenation and isomerization reactions are carried out, and the product is discharged from the lower end to obtain a hanging tetrahydrodicyclopentadiene.

[0007] wherein the upper section reaction temperature is 60-180℃, preferably 80℃-140℃; the lower section reaction temperature is 80-180℃, preferably 120℃-170℃. The overall fixed bed reaction pressure is 0.5MPa-5MPa, preferably 1.0MPa-3MPa; the mass space velocity is 0.2h -1 -5h -1 , preferably 0.5h -1 -2h -1 , and the hydrogen / hydrocarbon volume ratio is 200-1600, preferably 600-1200.

[0008] The hydrogenation catalyst is a conventional supported metal hydrogenation catalyst, the active metal is selected from one or more of Pt, Pd, Rh, Ru, Ni, etc., and the carrier is selected from non-acid carriers such as Al2O3, SiO2, TiO2, ZrO2, CeO2, activated carbon, etc.

[0009] The isomerization catalyst is a molecular sieve supported metal catalyst, the active metal is selected from one or more of Pd, Pt, Ru, Rh, Ni, preferably Pt and Pd; the molecular sieve is a Y-type molecular sieve, such as HY, USY, REHY, NEY, SSY, etc., preferably HY, USY, REHY.

[0010] The molecular sieve supported metal catalyst can be prepared by conventional methods, such as the equal volume impregnation method, the excess volume impregnation method, etc. In particular, a certain amount of metal precursor solution is prepared according to the metal loading, then impregnated on the molecular sieve, and placed at room temperature for more than 6h with intermittent stirring, then dried at 80℃ for more than 12h, and then calcined at 450℃-550℃ in air for 2h-5h. The calcined catalyst is reduced in a reducing atmosphere such as hydrogen at 400℃-550℃ for 2h-5h to obtain the activated catalyst.

[0011] The inert material is selected from SiO2, Al2O3, carbon materials, quartz sand, etc., preferably quartz sand.

[0012] The reaction solvent is a hydrocarbon with a boiling point of 40-200℃, such as cyclohexane, methylcyclohexane, dichloromethane, etc., preferably a C6-C10 hydrocarbon, such as cyclohexane, methylcyclohexane; after mixing with the reaction solvent, the mass concentration of the dicyclopentadiene is 10%-50%, preferably 10%-30%.

[0013] The method of the present application realizes continuous preparation of Exo-THDCPD in a fixed bed reactor, reduces the investment requirement for the device, reduces the operation cost, simplifies the whole process flow, and at the same time, the reaction conditions are mild, the yield of the product is high, and the system can be stably operated for a long period. DETAILED DESCRIPTION

[0014] The present application provides a method for continuously preparing Exo-THDCPD, which comprises: loading a conventional hydrogenation catalyst into an upper section of a fixed bed reactor, separating the middle section with inert material quartz sand, and loading an isomerization catalyst into a lower section; then mixing dicyclopentadiene and a reaction solvent uniformly and feeding them into the fixed bed reactor; and continuously converting the dicyclopentadiene into Exo-THDCPD through hydrogenation in the upper section and isomerization in the lower section, wherein the reaction temperature of the upper section is 60-180℃, the reaction temperature of the lower section is 80-180℃, the pressure of the whole fixed bed reactor is 0.5-5MPa, the mass space velocity is 0.2-5h-1, and the volume ratio of hydrogen to hydrocarbon is 200-1600. -1 -1 Since the dicyclopentadiene is relatively active due to its two double bonds, a conventional metal type hydrogenation catalyst can be used.

[0015] According to the present application, the dicyclopentadiene and the reaction solvent are uniformly premixed in a raw material tank, then pumped to the top end of the fixed bed reactor, and then the reaction product flows out from the lower end of the fixed bed. After the system is stable for 20h, a sample is taken out for gas chromatography analysis, and the conversion rate of the reactant and the selectivity of the product are calculated according to the area normalization method.

[0016] The specific embodiments of the present application are further illustrated below in combination with examples.

[0017] Example 1 (influence of different isomerization catalysts)

[0018] ​The raw material was methylcyclohexane solution containing 20wt% dicyclopentadiene; the hydrogenation catalyst was 20wt% Ni / SiO2, the reaction temperature in hydrogenation section was 100°C, the reaction temperature in isomerization section was 150°C, the whole fixed bed reaction pressure was 1 MPa, the mass space velocity was 1 h -1 The hydrogen / hydrocarbon volume ratio was 1000, and the influence of different isomerization catalysts was investigated. The results are shown in Table 1.

[0019] Table 1

[0020]

[0021] Example 2 (Influence of Different Reaction Temperatures)

[0022] The raw material was methylcyclohexane solution containing 20wt% dicyclopentadiene; the hydrogenation catalyst was 20wt% Ni / SiO2, the isomerization catalyst was 0.3% Pt / REHY, the whole fixed bed reaction pressure was 1 MPa, the mass space velocity was 1 h -1 The hydrogen / hydrocarbon volume ratio was 1000, and the influence of reaction temperature was investigated. The results are shown in Table 2.

[0023] Table 2

[0024]

[0025] Example 3 (Influence of Different Reaction Pressures)

[0026] The raw material was methylcyclohexane solution containing 20wt% dicyclopentadiene; the hydrogenation catalyst was 20wt% Ni / SiO2, the isomerization catalyst was 0.3% Pt / REHY, the reaction temperature in hydrogenation section was 100°C, the reaction temperature in isomerization section was 150°C, the mass space velocity was 1 h -1 The hydrogen / hydrocarbon volume ratio was 1000, and the influence of reaction pressure was investigated. The results are shown in Table 3.

[0027] Table 3

[0028]

[0029] Example 4 (Influence of Different Reaction Space Velocities)

[0030] The raw material was methylcyclohexane solution containing 20wt% dicyclopentadiene; the hydrogenation catalyst was 20wt% Ni / SiO2, the isomerization catalyst was 0.3% Pt / REHY, the reaction temperature in hydrogenation section was 100°C, the reaction temperature in isomerization section was 150°C, the whole fixed bed reaction pressure was 1 MPa, the hydrogen / hydrocarbon volume ratio was 1000, and the influence of reaction space velocity was investigated. The results are shown in Table 4.

[0031] Table 4

[0032]

[0033] Example 5 (Effect of different hydrogen / hydrocarbon volume ratio)

[0034] The methylcyclohexane solution containing 20wt% dicyclopentadiene was used as raw material; 20wt% Ni / SiO2 was used as hydrogenation catalyst and 0.3% Pt / REHY was used as isomerization catalyst; the temperature of hydrogenation section was 100°C, the temperature of isomerization section was 150°C, the pressure of the whole fixed bed reaction was 1 MPa, the mass space velocity was 1 h -1 , and the effect of hydrogen / hydrocarbon volume ratio was investigated. The results are shown in Table 5.

[0035] Table 5

[0036]

[0037] Example 6 (Effect of different solvents and solvent ratio)

[0038] The methylcyclohexane, cyclohexane, dichloromethane and isopropyl alcohol were used as reaction solvents to prepare 20wt% dicyclopentadiene reaction solution; the methylcyclohexane was used as reaction solvent to prepare dicyclopentadiene reaction solution with different concentrations; 20wt% Ni / SiO2 was used as hydrogenation catalyst and 0.3% Pt / REHY was used as isomerization catalyst; the temperature of hydrogenation section was 100°C, the temperature of isomerization section was 150°C, the pressure of the whole fixed bed reaction was 1 MPa, the mass space velocity was 1 h -1 , the hydrogen / hydrocarbon volume ratio was 1000, and the effect of different solvents and solvent ratio was investigated. The results are shown in Table 6.

[0039] Table 6

[0040]

[0041]

[0042] Example 29 (System running cycle investigation)

[0043] The methylcyclohexane solution containing 20wt% dicyclopentadiene was used as raw material; 20wt% Ni / SiO2 was used as hydrogenation catalyst and 0.3% Pt / REHY was used as isomerization catalyst; the temperature of hydrogenation section was 100°C, the temperature of isomerization section was 150°C, the pressure of the whole fixed bed reaction was 1 MPa, the mass space velocity was 1 h -1 , the hydrogen / hydrocarbon volume ratio was 1000, and the system running cycle was investigated. The results are shown in Table 7.

[0044] Table 7

[0045]

Claims

1. A method for the continuous synthesis of pedigree tetrahydrodicyclopentadiene, comprising: In a fixed-bed reactor, a hydrogenation catalyst is loaded in the upper section and separated by an inert material. An isomerization catalyst is loaded in the lower section. The feedstock dicyclopentadiene and the reaction solvent enter the fixed-bed reactor from the upper end for hydrogenation and isomerization reactions. The product flows out from the lower end, yielding hanging tetrahydrodicyclopentadiene. The reaction temperature in the upper section is 60℃-180℃, and the reaction temperature in the lower section is 80℃-180℃. The overall fixed-bed reaction pressure is 0.5MPa-3MPa, and the mass hourly space velocity (WHSV) is 0.2h⁻¹. -1 -5h -1 The hydrogen-to-hydrogen volume ratio is 200-1600, and the isomerization catalyst is a molecular sieve supported metal catalyst, wherein the active metal is selected from one or more of Pd, Pt, Ru, and Rh, and the molecular sieve is selected from HY, USY, and REHY.

2. The method according to claim 1, wherein, The upper reaction temperature is 80℃-140℃, and the lower reaction temperature is 120℃-170℃.

3. The method according to claim 1, wherein, The entire fixed-bed reaction pressure is 1.0 MPa-3 MPa, and the mass hourly space velocity is 0.5 h⁻¹. -1 -2h -1 The hydrogen-to-hydrogen volume ratio is 600-1200.

4. The method according to claim 1, wherein, The hydrogenation catalyst is a supported metal hydrogenation catalyst.

5. The method according to claim 1 or 4, wherein, In the hydrogenation catalyst, the active metal is selected from one or more of Pt, Pd, Rh, Ru, and Ni, and the support is selected from non-acidic supports such as Al2O3, SiO2, TiO2, ZrO2, CeO2, and activated carbon.

6. The method according to claim 1, wherein, The inert material is selected from SiO2, Al2O3, carbon materials, and quartz sand.

7. The method according to claim 1, wherein, The reaction solvent is a hydrocarbon with a boiling point of 40℃ to 200℃.

8. The method according to claim 1, wherein, The reaction solvent is selected from C6-C10 hydrocarbons.

9. The method according to claim 1, wherein, The reaction solvent is cyclohexane or methylcyclohexane.

10. The method according to claim 1, wherein, When dicyclopentadiene is mixed with the reaction solvent, the mass concentration of dicyclopentadiene is 10%-50%.

11. The method according to claim 1, wherein, When dicyclopentadiene is mixed with the reaction solvent, the mass concentration of dicyclopentadiene is 10%-30%.

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