Method for synthesizing cyclopentadiene from cyclopentanone

Abstract

The invention relates to the technical field of cyclopentadiene synthesis, in particular to a method for synthesizing cyclopentadiene from cyclopentanone. The method comprises the following steps: by taking cyclopentanone as a raw material, carrying out hydrodeoxygenation tandem dehydrogenation reaction in a fixed bed continuous reactor under the action of an AwBxCyOz type composite metal oxide catalyst or a C / ZnaAlbOc supported metal catalyst at the reaction temperature of 425-625 DEG C under the hydrogen pressure of 0.001 MPa, the molar ratio of hydrogen to cyclopentanone being (20-400): 1 and the weight hourly space velocity of cyclopentanone being 0.1-10h <-1 >, thereby obtaining cyclopentadiene. The method is simple in process route and environment-friendly, the catalyst is simple and convenient to prepare, and a more novel and efficient process route is provided for synthesizing cyclopentadiene from biomass-based cyclopentanone.

Description

Technical Field

[0001] The invention relates to the technical field of cyclopentadiene synthesis, and in particular to a method for synthesizing cyclopentadiene from cyclopentanone. Background Art

[0002] Cyclopentadiene, as a very important chemical, is the basic raw material for producing important organic chemicals such as ferrocene, norbornene, cyclopentene, adamantane, cyclopentane, halogenated cyclopentane and glutaraldehyde, and can also be used to prepare high value-added products such as petroleum resins and unsaturated resins and high-density aviation fuel JP-10. However, cyclopentadiene is extremely active in chemical properties and is generally sold, transported and stored in the form of dicyclopentadiene commercially. At present, the industrial preparation of cyclopentadiene mainly uses C5 obtained by cracking ethylene as a raw material, dimerizes cyclopentadiene into dicyclopentadiene at a certain temperature, and then separates high-purity dicyclopentadiene by vacuum distillation, and then heats and depolymerizes to obtain cyclopentadiene. CN1389444A discloses a method for preparing high-purity cyclopentadiene by thermal decomposition of crude dicyclopentadiene. The method uses a gas-liquid phase thermal decomposition method to add crude dicyclopentadiene into a thermal decomposer containing a heat-carrying liquid heated to 170-350°C, and collects the decomposition product at a condensation temperature of 42-80°C. Although the method is efficient and simple, the process route uses fossil energy with limited reserves and cannot be regenerated in a short time as raw materials, and involves repeated depolymerization and distillation processes, and the process equipment is complex and the energy consumption is high. Therefore, it is urgent to develop a new route for green and sustainable synthesis of cyclopentadiene.

[0003] CN113968776A discloses a method for preparing cyclopentanone from biomass raw materials. Under certain reaction conditions, the system can prepare high-yield cyclopentanone from hemicellulose, xylan, xylose and arabinose in raw materials in one step. However, up to now, there are few reports in the literature on the synthesis of cyclopentadiene using biomass cyclopentanone as raw material. This route needs to be further developed, the selectivity and conversion rate of the catalyst need to be further improved, and the stability of the catalyst is poor, making it difficult to achieve industrial application. Summary of the invention

[0004] In view of the above technical problems, the present invention adopts A w B x C y O z Type composite metal oxide catalyst and C / Zn a Al b O c Using a supported metal catalyst as a catalyst and cyclopentanone as a raw material, in a fixed bed continuous reactor, cyclopentanone is converted into the target product cyclopentadiene in one step through a series of hydrogenation, deoxygenation and dehydrogenation reactions, providing a more efficient catalyst for the biomass route of preparing high-value-added cyclopentadiene chemicals from cyclopentanone.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows:

[0006] The present invention provides a method for synthesizing cyclopentadiene from cyclopentanone, wherein cyclopentanone is used as a raw material, and in a fixed bed continuous reactor, w B x C y O z Type composite metal oxide catalyst or C / Zn a Al b O c Under the action of supported metal catalyst, the reaction is carried out by hydrogenation deoxygenation in series, the reaction temperature is 425-625℃, the hydrogen pressure is 0.001MPa, the molar ratio of hydrogen to cyclopentanone is 20-400:1, and the weight hourly space velocity of cyclopentanone is 0.1-10h -1 , to obtain cyclopentadiene;

[0007] The A w B x C y O z In the composite metal oxide, A is selected from one of Zn, Al, and Fe, B is selected from one of Mo, W, Cr, Fe, Ni, and Co, and C is selected from one of W, V, and Mo, and A, B, and C are different elements, w=0.5-1, x=1-2, y=0.05-1, and z=2.125-15.5;

[0008] The C / Zn a Al b O c Among supported metal catalysts, Zn a Al b O c is a carrier, wherein a:b=3:1, c=a+1.5b, C is an active component, and C is one of W, V, and Mo.

[0009] The chemical structural formulas of the above-mentioned raw material cyclopentanone and the target product cyclopentadiene are shown in Table 1.

[0010] Table 1 Structural formula of compounds

[0011]

[0012] Based on the above scheme, preferably, the reaction temperature is 525-625°C, the molar ratio of hydrogen to cyclopentanone is 30-350:1, and the hourly space velocity of cyclopentanone is 0.05-9h -1 .

[0013] Based on the above scheme, preferably, the reaction temperature is 550-600°C, the molar ratio of hydrogen to cyclopentanone is 50-300:1, and the hourly space velocity of cyclopentanone is 0.1-8h -1 .

[0014] Based on the above scheme, preferably, the C / Zn a Al b O c In the supported metal catalyst, the loading amount of the active component is 15-30%.

[0015] Based on the above scheme, preferably, the A w B x C y O z The composite metal oxide catalyst is ZnW2V 0.4 O8, ZnMo2V 0.2 O 7.5 ,AlWV 0.1 O 4.75 , ZnWV 0.05 O 2.125 、ZnW2VO 15.5 , Fe 0.5 WV 0.2 O8, ZnCr2MoO 5.5 、ZnW2V 0.2 O 7.5 .

[0016] Based on the above scheme, preferably, the A w B x C y O z The composite metal oxide catalyst is prepared by hydrothermal method. The specific preparation process is as follows:

[0017] The metal salts of A, B and C are mixed and dissolved in deionized water, and ultrasonicated at room temperature to obtain a suspension; the suspension is reacted at 80-220°C for 5-48h, the reaction temperature is preferably 90-200°C, more preferably 100-180°C, the reaction time is preferably 6-42h, more preferably 8-36h, filtered, washed, dried at 80°C for 1-8h, preferably 2-6h, more preferably 3-5h, and then calcined at 250-800°C for 0.5-6h, the calcination temperature is preferably 350-750°C, more preferably 400-700°C, and the calcination time is preferably 1-5h, more preferably 1-4h, to obtain A. w B x C y O z Type composite metal oxide catalyst.

[0018] Based on the above scheme, preferably, the A w Bx C y O z The composite metal oxide catalyst is prepared by precipitation method, and the specific preparation process is as follows:

[0019] The metal salts of B and C are dissolved in deionized water at a concentration of 0.5-14 mol / L, preferably 1-8 mol / L, more preferably 1.5-6 mol / L, and an aqueous ammonia solution is used as a precipitant to adjust the pH value to 8-14 to obtain a mixed solution; the aqueous metal salt solution of A is mixed with the mixed solution, and stirred for 0.5-4 h, preferably 1-3.5 h, more preferably 1-3 h, and the obtained precipitate is filtered, washed with deionized water and ethanol, dried at 50-120° C. for 4-48 h, and then calcined at 300-800° C. for 0.5-10 h, the calcination temperature is preferably 350-750° C., more preferably 400-700° C., and the calcination time is preferably 1-8 h, more preferably 1-6 h, to obtain A. w B x C y O z Type composite metal oxide catalyst.

[0020] Based on the above scheme, preferably, the A w B x C y O z The composite metal oxide catalyst is prepared by citric acid complexation method, and the specific preparation process is as follows:

[0021] The molar ratio of M: citric acid is 1:1.05-1:1-0.5:3, preferably 1:1.05-1:1-0.5:2, and more preferably 1:1.05-1:1-0.5:1.5. The metal salt of C, the metal salt of B, the metal salt of A, and citric acid are weighed, where M is the total molar sum of metal C, metal B, and metal A, and they are dissolved in deionized water to obtain metal C solution, metal B solution, and metal A solution, respectively; the metal C solution, the metal B solution, and the metal A solution are uniformly mixed, heated and evaporated in an evaporating dish, dried at 120° C. for 12 h, and then calcined at 300-800° C. for 0.5-10 h, the calcination temperature is preferably 350-750° C., and more preferably 400-700° C., and the calcination time is preferably 1-8 h, and more preferably 1-6 h, to obtain A. w B x C y O z Type composite metal oxide catalyst.

[0022] Based on the above scheme, preferably, the C / Zn a Al b O c The specific preparation process of the supported metal catalyst is as follows:

[0023] Weigh the metal salt solution of C, dissolve it in deionized water, and add it to the calcined Zn a Al b O c On the carrier, the calcination temperature is 300-800°C, preferably 300-700°C, more preferably 350-650°C, the calcination time is 0.5-12h, preferably 1-12h, more preferably 2-10h, and the stirring is 0.5-24h, preferably 1-24, more preferably 2-20h; after rotary evaporation at 70-90°C, preferably 75-90°C, more preferably 75-85°C, dried at 50-120°C for 0.5-12h, the drying temperature is preferably 60-110°C, more preferably 70-100°C, the drying time is preferably 2-12h, more preferably 2-8h, and then calcined at 300-800°C for 1-10h, the calcination temperature is preferably 300-750°C, more preferably 300-700°C, and the calcination time is preferably 1-8h, more preferably 1-7h, to obtain the supported metal catalyst.

[0024] Based on the above scheme, preferably, the catalyst is reduced in hydrogen before use; wherein the conditions for the reduction treatment are: hydrogen pressure 0.001-2.0MPa, preferably 0.005-1.5MPa, more preferably 0.01-1MPa, hydrogen flow rate 20-300mL / min, preferably 5-250mL / min, more preferably 10-200mL / min, reduction temperature 450-650°C, preferably 450-620°C, more preferably 480-610°C, reduction time 0.5-12h, preferably 0.7-10h, more preferably 1-8h.

[0025] The catalyst synthesized by the method described in the present invention can realize the direct synthesis of high-value-added cyclopentadiene from the biomass platform compound cyclopentanone, and provides a new catalyst design idea for the biomass synthesis route of cyclopentadiene.

[0026] The beneficial effects of the present invention are:

[0027] The process route of the invention is simple, easy to operate, and environmentally friendly. The cyclopentanone can be converted into cyclopentadiene in one step through a hydrogenation and deoxygenation series dehydrogenation reaction, which is a new green and efficient approach.

[0028] The catalyst of the invention is simple to prepare and can be synthesized in large quantities. The reaction conditions are mild, the cyclopentanone conversion rate is above 95%, the cyclopentadiene selectivity is above 90%, the catalytic performance is good, and the stability is good. After the reaction for 48 hours, the cyclopentadiene selectivity is still maintained at above 90%.

[0029] The present invention A w B x C y Oz The composite structure of the composite metal oxide catalyst is conducive to reducing the catalyst reduction temperature, increasing the content of oxygen vacancies and acidity, and the addition of the C element produces a synergistic effect with the B element, so that the catalyst has better cyclopentadiene selectivity and cyclopentanone conversion rate than the ABO type catalyst, and the catalyst of the present invention has higher stability; the use of Zn a Al b O c The supported metal catalyst is a carrier and one of W, V and Mo is an active component. The dispersion of the active component is improved, the mechanical properties of the catalyst are enhanced, and the Al on the carrier is 3+ The invention provides abundant Lewis acid sites, which is beneficial to promote the dehydrogenation reaction and improve the yield of catalytic conversion of cyclopentanone to cyclopentadiene. w B x C y O z Type composite metal oxide or C / Zn a Al b O c The supported metal catalyst is used in a fixed-bed continuous reactor to directly synthesize high value-added cyclopentadiene in one step through a series of hydrogenation, deoxygenation and dehydrogenation reactions. This method has excellent raw material conversion rate and product selectivity, and has the advantages of high operability, low energy consumption and environmental friendliness, and can be used for actual industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a gas chromatogram of the product of synthesizing cyclopentadiene from cyclopentanone in Example 20;

[0031] Figure 2 This is a mass spectrum comparison chart of the target product cyclopentadiene in Example 20. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to these embodiments.

[0033] Example 1

[0034] A w B x C y O z Composite metal oxide catalyst ZnW2V 0.4 Preparation of O8, the specific preparation process is:

[0035] 0.56 g of ammonium metavanadate and 5.91 g of ammonium metatungstate were dissolved in 200 mL of deionized water, and a 4 mol / L ammonia aqueous solution was used as a precipitant to adjust the pH value to 11 to obtain a mixed solution; 3.57 g of zinc nitrate was dissolved in 100 mL of deionized water to obtain a zinc nitrate aqueous solution, and the zinc nitrate aqueous solution was added dropwise to the mixed solution and stirred for 2 h. The obtained precipitate was filtered, washed with deionized water and ethanol, dried at 60 ° C for 4 h, and then calcined at 300 ° C for 4 h to obtain ZnW2V 0.4 O8 type composite metal oxide catalyst.

[0036] The above ZnW2V 0.4 0.5 g of O8 catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 1 h at a hydrogen pressure of 0.001 MPa, a hydrogen flow rate of 150 mL / min, and a reduction temperature of 550 ° C. Then, the reaction temperature was controlled to be 550 ° C, the hydrogen pressure was 0.001 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, and the hourly space velocity of cyclopentanone was 0.13 h -1 The conversion rate of cyclopentanone is 100% and the selectivity of cyclopentadiene is 90%.

[0037] Example 2

[0038] A w B x C y O z Composite metal oxide catalyst ZnMo2V 0.2 O 7.5 The specific preparation process is as follows:

[0039] 0.28 g of ammonium metavanadate and 4.24 g of ammonium molybdate were dissolved in 200 mL of deionized water, and a 4 mol / L ammonia aqueous solution was used as a precipitant to adjust the pH value to 11.5 to obtain a mixed solution; 3.57 g of zinc nitrate was dissolved in 100 mL of deionized water to obtain a zinc nitrate aqueous solution, and the zinc nitrate aqueous solution was added dropwise to the mixed solution and stirred for 2 h. The obtained precipitate was filtered, washed with deionized water and ethanol, dried at 60 ° C for 4 h, and then calcined at 300 ° C for 4 h to obtain ZnMo2V 0.2 O 7.5 Type composite metal oxide catalyst.

[0040] The above ZnMo2V 0.2 O 7.51 g of the catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 1 h at a hydrogen pressure of 0.001 MPa, a hydrogen flow rate of 150 mL / min, and a reduction temperature of 550° C., and then the reaction temperature was controlled to be 550° C., the hydrogen pressure was 0.001 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, and the hourly space velocity of cyclopentanone was 0.13 h -1 The conversion rate of cyclopentanone is 100% and the selectivity of cyclopentadiene is 92%.

[0041] Example 3

[0042] A w B x C y O z AlWV composite metal oxide catalyst 0.1 O 4.75 Preparation:

[0043] 0.28 g of ammonium metavanadate and 4.24 g of ammonium metatungstate were dissolved in 200 mL of deionized water, and a 4 mol / L ammonia aqueous solution was used as a precipitant to adjust the pH value to 11.5 to obtain a mixed solution; 2.56 g of aluminum nitrate was dissolved in 100 mL of deionized water to obtain an aluminum nitrate aqueous solution, and the aluminum nitrate aqueous solution was added dropwise to the mixed solution and stirred for 2 h. The obtained precipitate was filtered, washed with deionized water and ethanol, dried at 60 ° C for 4 h, and then calcined at 300 ° C for 4 h to obtain AlWV 0.1 O 4.75 Type composite metal oxide catalyst.

[0044] The above AlWV 0.1 O 4.75 0.5 g of the catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 1 h at a hydrogen pressure of 0.001 MPa, a hydrogen flow rate of 150 mL / min, and a reduction temperature of 550° C., and then the reaction temperature was controlled to be 550° C., the hydrogen pressure was 0.001 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, and the hourly space velocity of cyclopentanone was 0.13 h -1 The conversion rate of cyclopentanone is 100% and the selectivity of cyclopentadiene is 92%.

[0045] Example 4

[0046] A w B x C y O z ZnWV composite metal oxide catalyst 0.05 O 2.125 The specific preparation process is as follows:

[0047] 0.07 g of ammonium metavanadate and 2.96 g of ammonium metatungstate were dissolved in 200 mL of deionized water, and a 4 mol / L ammonia solution was used as a precipitant to adjust the pH value to 11.5; 3.56 g of zinc nitrate was dissolved in 100 mL of deionized water to obtain a zinc nitrate aqueous solution, and the zinc nitrate aqueous solution was added dropwise to the mixed solution obtained above, stirred for 2 h, and the obtained precipitate was filtered, washed with deionized water and ethanol, dried at 60 ° C for 4 h, and then calcined at 300 ° C for 4 h to obtain ZnWV 0.05 O 2.125 Type composite metal oxide catalyst.

[0048] The above ZnWV 0.05 O 2.125 0.5 g of the catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 1 h at a hydrogen pressure of 0.001 MPa, a hydrogen flow rate of 150 mL / min, and a reduction temperature of 550° C., and then the reaction temperature was controlled to be 550° C., the hydrogen pressure was 0.001 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, and the hourly space velocity of cyclopentanone was 0.13 h -1 The conversion rate of cyclopentanone is 100% and the selectivity of cyclopentadiene is 88%.

[0049] Example 5

[0050] A w B x C y O z Composite metal oxide catalyst ZnW2VO 15.5 The specific preparation process is as follows:

[0051] 1.4 g of ammonium metavanadate and 5.9 g of ammonium metatungstate were dissolved in 200 mL of deionized water, and a 4 mol / L ammonia solution was used as a precipitant to adjust the pH value to 11.5; 3.57 g of zinc nitrate was dissolved in 100 mL of deionized water to obtain a zinc nitrate aqueous solution, and the zinc nitrate aqueous solution was added dropwise to the mixed solution obtained above, stirred for 2 h, and the obtained precipitate was filtered, washed with deionized water and ethanol, dried at 60 ° C for 4 h, and then calcined at 300 ° C for 4 h to obtain ZnW2VO 15.5 Type composite metal oxide catalyst.

[0052] The above ZnW2VO 15.50.5 g of the catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 1 h at a hydrogen pressure of 0.001 MPa, a hydrogen flow rate of 150 mL / min, and a reduction temperature of 550° C., and then the reaction temperature was controlled to be 550° C., the hydrogen pressure was 0.001 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, and the hourly space velocity of cyclopentanone was 0.13 h -1 The conversion rate of cyclopentanone is 99% and the selectivity of cyclopentadiene is 88%.

[0053] Example 6

[0054] A w B x C y O z Type composite metal oxide catalyst Fe 0.5 WV 0.2 Preparation of O8, the specific preparation process is:

[0055] 0.28 g of ammonium metavanadate and 5.91 g of ammonium metatungstate were dissolved in 200 mL of deionized water, and a 4 mol / L ammonia solution was used as a precipitant to adjust the pH value to 11.5; 2.42 g of ferric nitrate was dissolved in 100 mL of deionized water to obtain an aqueous solution of ferric nitrate, and the aqueous solution of ferric nitrate was added dropwise to the mixed solution obtained above, stirred for 2 h, and the obtained precipitate was filtered, washed with deionized water and ethanol, dried at 60 ° C for 4 h, and then calcined at 300 ° C for 4 h to obtain Fe 0.5 WV 0.2 O8 type composite metal oxide catalyst.

[0056] The above Fe 0.5 WV 0.2 0.5 g of O8 catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 1 h at a hydrogen pressure of 0.001 MPa, a hydrogen flow rate of 150 mL / min, and a reduction temperature of 550 ° C. Then, the reaction temperature was controlled to be 550 ° C, the hydrogen pressure was 0.001 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, and the hourly space velocity of cyclopentanone was 0.13 h -1 The conversion rate of cyclopentanone is 95% and the selectivity of cyclopentadiene is 92%.

[0057] Example 7

[0058] AwBxCyOz type composite metal oxide catalyst ZnCr2MoO 5.5 The specific preparation process is as follows:

[0059] 2.12 g of ammonium molybdate and 9.6 g of chromium nitrate were dissolved in 200 mL of deionized water, and a 4 mol / L ammonia solution was used as a precipitant to adjust the pH value to 11.5; 3.57 g of zinc nitrate was dissolved in 100 mL of deionized water to obtain a zinc nitrate aqueous solution, and the zinc nitrate aqueous solution was added dropwise to the mixed solution obtained above, stirred for 2 h, and the obtained precipitate was filtered, washed with deionized water and ethanol, dried at 60 ° C for 4 h, and then calcined at 300 ° C for 4 h to obtain ZnCr2MoO 5.5 Type composite metal oxide catalyst.

[0060] The above ZnCr2MoO 5.5 0.5 g of the catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 1 h at a hydrogen pressure of 0.001 MPa, a hydrogen flow rate of 150 mL / min, and a reduction temperature of 550° C., and then the reaction temperature was controlled to be 550° C., the hydrogen pressure was 0.001 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, the hourly space velocity of cyclopentanone was 0.13 h-1, the conversion rate of cyclopentanone was 98%, and the selectivity of cyclopentadiene was 93%.

[0061] Example 8

[0062] A w B x C y O z ZnWV composite metal oxide catalyst 0.2 O 4.5 The specific preparation process is as follows:

[0063] 3.57g zinc nitrate, 0.28g ammonium metavanadate, and 2.95g ammonium metatungstate were dissolved in deionized water and ultrasonicated at room temperature to obtain a suspension. The suspension was reacted at 160°C for 6h, filtered, washed, dried at 120°C for 12h, and then calcined at 300°C for 4h to obtain ZnWV 0.2 O 4.5 Type composite metal oxide catalyst.

[0064] The above ZnFeW 0.5 0.5 g of O4 catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 1 h at a hydrogen pressure of 0.001 MPa, a hydrogen flow rate of 150 mL / min, and a reduction temperature of 550 ° C. Then, the reaction temperature was controlled to be 550 ° C, the hydrogen pressure was 0.001 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, and the hourly space velocity of cyclopentanone was 0.13 h -1 The conversion rate of cyclopentanone is 100% and the selectivity of cyclopentadiene is 91%.

[0065] Example 9

[0066] A w B x C y O z ZnFeW composite metal oxide catalyst 0.5 Preparation of O4, the specific preparation process is as follows: first, 3.57g zinc nitrate, 4.84g iron nitrate, 1.48g ammonium metatungstate, dissolved in deionized water to prepare a solution, EDTA dissolved in 4mol / L ammonia water, and then the metal salt solution was poured into EDTA-NH3·H2O buffer solution, heated and stirred; then, a certain amount of citric acid was added, wherein the molar ratio of EDTA, citric acid and Zn, Fe, W metal ions was 1:1.5:1:1:0.5, and the pH value was adjusted to 7.0 with ammonia water; the solution was heated and stirred at 80°C to obtain a light yellow gel, and the gel was placed in an oven and dried at 120°C for 12h. Finally, the dried gel was calcined at 300°C for 4h to obtain ZnFeW 0.5 O4 type composite metal oxide catalyst.

[0067] The above ZnFeW 0.5 0.5 g of O4 catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 1 h at a hydrogen pressure of 0.001 MPa, a hydrogen flow rate of 150 mL / min, and a reduction temperature of 550 ° C. Then, the reaction temperature was controlled to be 550 ° C, the hydrogen pressure was 0.001 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, and the hourly space velocity of cyclopentanone was 0.13 h -1 The conversion rate of cyclopentanone is 97% and the selectivity of cyclopentadiene is 87%.

[0068] Example 10

[0069] Supported metal catalyst 30% W / Zn3AlO 4.5 The specific preparation process is as follows:

[0070] Dissolve 3.57 g zinc nitrate in 100 mL deionized water to obtain a zinc nitrate aqueous solution, dissolve aluminum nitrate in deionized water to obtain an aluminum nitrate aqueous solution, and dropwise add the zinc nitrate aqueous solution into the aluminum nitrate solution to obtain Zn3AlO 4.5 Carrier: Weigh 1.15g of ammonium metatungstate and dissolve it in 40ml of deionized water, to which 2g of Zn3AlO calcined at 400℃ for 2h in a muffle furnace is added. 4.5 The carrier was stirred for 6 hours and then the excess water was removed by rotary evaporation at 80°C. After drying at 120°C for 3 hours, it was calcined at 600°C in a tube furnace for 1 hour to obtain 30% W / Zn3AlO 4.5 catalyst.

[0071] The above 30% W / Zn3AlO 4.5 1 g of the catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 1 h at a hydrogen pressure of 0.10 MPa, a hydrogen flow rate of 150 mL / min, and a reduction temperature of 550° C., and then the reaction temperature was controlled to be 550° C., the hydrogen pressure was 0.08 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, and the hourly space velocity of cyclopentanone was 0.13 h -1 The conversion rate of cyclopentanone is 100% and the selectivity of cyclopentadiene is 91%.

[0072] Embodiment 11

[0073] Supported metal catalyst 15% V / Zn3AlO 4.5 Preparation: Weigh 0.36g of ammonium metavanadate and dissolve it in 40ml of deionized water, add 2g of Zn3AlO calcined at 400℃ in a muffle furnace for 2h 4.5 The carrier was stirred for 6 hours and then the excess water was removed by rotary evaporation at 80°C. After drying at 120°C for 3 hours, it was calcined at 600°C in a tube furnace for 1 hour to obtain 15% W / Zn3AlO 4.5 catalyst.

[0074] The above 15% V / Zn3AlO 4.5 1 g of the catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 2 h at a hydrogen pressure of 0.001 MPa, a hydrogen flow rate of 150 mL / min, and a reduction temperature of 550 ° C. Then, the reaction temperature was controlled to be 550 ° C, the hydrogen pressure was 0.001 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, and the hourly space velocity of cyclopentanone was 0.13 h -1 The conversion rate of cyclopentanone is 100% and the selectivity of cyclopentadiene is 94%.

[0075] Example 12

[0076] Supported metal catalyst 20% Mo / Zn3AlO 4.5 Preparation of catalyst: Weigh 0.24g ammonium molybdate and dissolve it in 40ml deionized water, add 2g Zn3AlO calcined in a muffle furnace at 400℃ for 2h 4.5 The carrier was stirred for 6 hours and then the excess water was removed by rotary evaporation at 80°C. After drying at 120°C for 3 hours, it was calcined at 600°C in a tube furnace for 1 hour to obtain 20% W5% V / Zn3AlO 4.5 catalyst;

[0077] The above 20% Mo / Zn3AlO 4.51 g of the catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 0.5 h at a hydrogen pressure of 0.001 MPa, a hydrogen flow rate of 90 mL / min, and a reduction temperature of 550° C., and then the reaction temperature was controlled to be 550° C., the hydrogen pressure was 0.001 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, and the hourly space velocity of cyclopentanone was 0.13 h -1 The conversion rate of cyclopentanone is 100% and the selectivity of cyclopentadiene is 93%.

[0078] The test results of the above-mentioned embodiments 1-12 are shown in Table 2.

[0079] Table 2 Test results of cyclopentadiene synthesis from cyclopentanone

[0080]

[0081]

[0082] Embodiment 13

[0083] A w B x C y O z Composite metal oxide catalyst ZnW2V 0.2 O 7.5 The specific preparation process is as follows:

[0084] 0.28 g of ammonium metavanadate and 5.91 g of ammonium metatungstate were dissolved in 200 mL of deionized water, and a 4 mol / L ammonia solution was used as a precipitant to adjust the pH value to 11.5; 3.57 g of zinc nitrate was dissolved in 100 mL of deionized water to obtain a zinc nitrate aqueous solution, and the zinc nitrate aqueous solution was added dropwise to the mixed solution obtained above, stirred for 2 h, and the obtained precipitate was filtered, washed with deionized water and ethanol, dried at 60 ° C for 4 h, and then calcined at 300 ° C for 4 h to obtain ZnW2V 0.2 O 7.5 Type composite metal oxide catalyst.

[0085] The above ZnW2V 0.2 O 7.5 1 g of the catalyst was uniformly mixed with 2 g of quartz sand (40-70 mesh), loaded into a fixed bed continuous reactor, and then reduced for 1 h at a hydrogen pressure of 0.001 MPa, a hydrogen flow rate of 150 mL / min, and a reduction temperature of 550° C., and then the reaction temperature was controlled to be 550° C., the hydrogen pressure was 0.001 MPa, the molar ratio of hydrogen to cyclopentanone was 87:1, and the hourly space velocity of cyclopentanone was 0.13 h -1 The conversion rate of cyclopentanone is 100% and the selectivity of cyclopentadiene is 95%.

[0086] Examples 14-28

[0087] Using the ZnW2V prepared in Example 13 0.2 O 7.5 The catalyst was added, and the reaction temperature and hourly space velocity conditions were changed. The other reaction conditions were the same as those in Example 13.

[0088] Table 3 ZnW2V under different reaction conditions 0.2 O 7.5 Test results of catalytic cyclopentanone to cyclopentadiene

[0089] Example Reaction temperature℃ <![CDATA[Space-time velocity h -1 > Cyclopentanone conversion rate / % Cyclopentadiene selectivity % Embodiment 14 425 0.13 100 90 Embodiment 15 475 0.13 100 91 Example 16 525 0.13 100 93 Embodiment 17 575 0.13 100 95 Embodiment 18 600 0.13 100 96 Embodiment 19 625 0.13 100 92 Embodiment 20 600 0.10 100 91 Embodiment 21 600 0.16 100 97 Embodiment 22 600 0.19 100 98 Embodiment 23 600 0.22 100 93 Embodiment 24 600 0.5 100 89 Embodiment 25 600 1 100 87 Embodiment 26 600 3 100 83 Embodiment 27 600 5 100 78 Embodiment 28 600 10 100 72

[0090] Embodiment 29

[0091] After reacting for 48 hours under the same conditions as in Example 18, the cyclopentanone conversion rate was still 100%, and the selectivity of the target product was as high as 92%.

[0092] Examples 30-39

[0093] The 30% W / Zn3AlO prepared in Example 10 was used. 4.5 The catalyst was added, and the reaction temperature and hourly space velocity conditions were changed. The other reaction conditions were the same as those in Example 10.

[0094] Table 4 30% W / Zn3AlO under different reaction conditions 4.5 Test results of catalytic synthesis of cyclopentadiene from cyclopentanone

[0095]

[0096]

[0097] Embodiment 40

[0098] After reacting for 43 hours under the same conditions as in Example 32, the cyclopentanone conversion rate was still 100%, and the selectivity of the target product was as high as 94%.

[0099] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the implementation methods. The protection scope of the present invention shall be subject to the scope defined in the claims. Other different forms of changes or modifications may be made based on the above description. Obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for synthesizing cyclopentadiene from cyclopentanone, characterized in that: Cyclopentanone was used as raw material in a fixed bed continuous reactor. w B x C y O z Type composite metal oxide catalyst or C / Zn a Al b O c Under the action of supported metal catalyst, the reaction is carried out by hydrogenation deoxygenation in series, the reaction temperature is 425-625℃, the hydrogen pressure is 0.001MPa, the molar ratio of hydrogen to cyclopentanone is 20-400:1, and the weight hourly space velocity of cyclopentanone is 0.1-10h -1 , to obtain cyclopentadiene; The A w B x C y O z In the composite metal oxide, A is selected from one of Zn, Al, and Fe, B is selected from one of Mo, W, Cr, Fe, Ni, and Co, and C is selected from one of W, V, and Mo, and A, B, and C are different elements, w=0.5-1, x=1-2, y=0.05-1, and z=2.125-15.5; The C / Zn a Al b O c Among supported metal catalysts, Zn a Al b O c is a carrier, wherein a:b=3:1, c=a+1.5b, C is an active component, and C is one of W, V, and Mo.

2. The method according to claim 1, characterized in that: The reaction temperature is 525-625°C, the molar ratio of hydrogen to cyclopentanone is 30-350:1, and the hourly space velocity of cyclopentanone is 0.05-9h -1 .

3. The method according to claim 2, characterized in that: The reaction temperature is 550-600°C, the molar ratio of hydrogen to cyclopentanone is 50-300:1, and the hourly space velocity of cyclopentanone is 0.1-8h -1 .

4. The method according to claim 1, characterized in that: The C / Zn a Al b O c In the supported metal catalyst, the loading amount of the active component is 15-30%.

5. The method according to claim 1, characterized in that: The A w B x C y O z The composite metal oxide catalyst is ZnW2V 0.4 O8, ZnMo2V 0.2 O 7.5 ,AlWV 0.1 O 4.75 , ZnWV 0.05 O 2.125 、ZnW2VO 15.5 , Fe 0.5 WV 0.2 O8, ZnCr2MoO 5.5 、ZnW2V 0.2 O 7.5 .

6. The method according to claim 1, characterized in that: The A w B x C y O z The composite metal oxide catalyst is prepared by hydrothermal method. The specific preparation process is as follows: The metal salts of A, B and C are mixed and dissolved in deionized water, and ultrasonicated at room temperature to obtain a suspension; the suspension is reacted at 80-220°C for 5-48h, filtered, washed, dried at 80°C for 1-8h, and then calcined at 250-800°C for 0.5-6h to obtain A w B x C y O z Type composite metal oxide catalyst.

7. The method according to claim 1, characterized in that: The A w B x C y O z The composite metal oxide catalyst is prepared by precipitation method, and the specific preparation process is as follows: The metal salts of B and C are dissolved in deionized water, and the pH value is adjusted to 8-14 using a 0.5-14 mol / L ammonia solution as a precipitant to obtain a mixed solution; the metal salt aqueous solution of A is mixed with the mixed solution, stirred for 0.5-4h, the obtained precipitate is filtered, washed with deionized water and ethanol, dried at 50-120°C for 4-48h, and then calcined at 300-800°C for 0.5-10h to obtain A w B x C y O z Type composite metal oxide catalyst.

8. The method according to claim 1, characterized in that: The A w B x C y O z The composite metal oxide catalyst is prepared by citric acid complexation method, and the specific preparation process is as follows: Weigh the metal salt of C, the metal salt of B, the metal salt of A, and citric acid at a molar ratio of M: citric acid = 1:1.05 to 1:1 to 0.5:3, where M is the total molar sum of metal C, metal B, and metal A, and dissolve them in deionized water to obtain metal C solution, metal B solution, and metal A solution, respectively; The metal C solution, metal B solution and metal A solution are uniformly mixed, heated and evaporated in an evaporating dish, dried at 120°C for 12 hours, and then calcined at 300-800°C for 0.5-10 hours to obtain A w B x C y O z Type composite metal oxide catalyst.

9. The method according to claim 1, characterized in that: The C / Zn a Al b O c The specific preparation process of the supported metal catalyst is as follows: weigh the metal salt solution of C, dissolve it in deionized water, add it to Zn calcined at 300-800℃ for 0.5-12h, a Al b O c on a carrier, stirring for 0.5-24h; after rotary evaporation at 70-90°C, drying at 50-120°C for 0.5-12h, and calcining at 300-800°C for 1-10h to obtain the supported metal catalyst.

10. The method according to claim 1, characterized in that: The catalyst is subjected to reduction treatment in hydrogen before use; wherein the conditions for the reduction treatment are: hydrogen pressure 0.001-2.0 MPa, hydrogen flow rate 20-300 mL / min, temperature 450-650° C., and time 0.5-12 h.

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