CN114315504A - Method for preparing methyl cyclopentadiene by catalyzing AxByOz type composite metal oxide - Google Patents

Abstract

The invention relates to a method for converting 2,5-hexanedione or 3-methyl-2-cyclopentene-1-ketone into methylcyclopentadiene in one step by using AxByOz type composite metal oxide for hydrodeoxygenation reaction . A variety of AxByOz-type composite metal oxides can be synthesized using simple and easy-to-operate deposition precipitation methods, hydrothermal methods or citric acid complexation methods, which are suitable for 2,5-hexanedione and 3-methyl-2-cyclopentene- The hydrodeoxygenation reaction of 1-ketone has special selectivity, and the target product can be synthesized in one step through aldol condensation series hydrodeoxygenation reaction or direct hydrodeoxygenation reaction at a large mass space velocity in a fixed bed reactor. Methylcyclopentadiene. The invention has the advantages of simple process route, environmental friendliness and simple catalyst preparation, and provides a brand-new catalytic method for the synthesis of methylcyclopentadiene.

Description

Method for preparing methylcyclopentadiene catalyzed by AxByOz type composite metal oxide

technical field

The present invention relates to a method for synthesizing methylcyclopentadiene from 2,5-hexanedione and 3-methyl-2-cyclopenten-1-one.

Background technique

Methylcyclopentadiene can not only synthesize high-energy rocket fuel, but also a high-end fine chemical raw material with a wide range of uses. It can be used to synthesize gasoline antiknock agent methylcyclopentadiene manganese tricarbonyl (MMT), epoxy resin curing agent, Dye additives, special binders, special spices and other high value-added products. At present, there are two main methods for the production of MCPD in industry: one is to use petroleum pyrolysis tar as raw material, first to separate the C ₆ components by distillation, and then to obtain the Preparation of MCPD; another is the preparation of MCPD by methylation of cyclopentadiene. However, whether MCPD is produced by separation or methylation synthesis, the production capacity is very limited, which is far from meeting the application needs of various fields. Therefore, it is of great significance to find a green and renewable synthetic process route for the production of methylcyclopentadiene using bulk chemicals as raw materials.

In recent years, with people's increasing attention to environmental and energy issues, the synthesis of high value-added chemicals from carbon dioxide-neutral and renewable biomass resources has received extensive attention from countries around the world. For example, 2,5-hexanedione can be obtained by subjecting cellulose to catalytic hydrogenolysis (Appl. Catal. A, 2015, 504, 664-671). Using 2,5-hexanedione as raw material, under the action of basic catalyst Mg-Al-O, and using water-toluene mixed solvent, aldol condensation reaction can be carried out to obtain 3-methyl-2-cyclopentene-1 - Ketone (MCP), MCP can undergo hydrodeoxygenation under the action of catalyst Pt/NbOPO ₄ to obtain methylcyclopentane, which has a lower carbon number and loses the ability to further polymerize (Green Chem., 2015, 17, 2393-2397). Using MCP as a raw material, methylcyclopentadiene can be obtained by one-step hydrodeoxygenation. The highest selectivity of methylcyclopentadiene is only 80%, the yield of the target product is low, and only a single substance can be used, that is, the price is relatively high. Higher MCP as a raw material problem.

SUMMARY OF THE INVENTION

In view of the above technical problems, the present invention adopts a variety of synthesis methods to provide a novel AxByOz type composite metal oxide catalyst, which can efficiently convert 2,5-hexanedione or 3-methyl-2-cyclopenten-1-one in one step It is converted into the target product methylcyclopentadiene, and provides a novel, simple and efficient synthesis method for the synthesis of high value-added methylcyclopentadiene.

The present invention is achieved through the following technical solutions:

The technical solution of the present invention includes method 1 or method 2, and the paths of the method 1 and method 2 are as follows:

method 1

Method 2

The AxByOz type composite metal oxide catalyst includes: CuMoO ₄ , Cu ₃ Mo ₂ O ₉ , ZnMoO ₄ , Zn ₃ Mo ₂ O ₉ , NiMoO ₄ , CoMoO ₄ , MnMoO ₄ , FeMoO ₄ , Fe ₂ (MoO ₄ ) _3. One or more of Cr ₂ (MoO ₄ ) ₃ , CuWO ₄ , NiWO ₄ , CoWO ₄ , FeWO ₄ , ZnWO ₄ , and Zn ₃ (VO ₄ ) ₂ .

The chemical structural formulas of above-mentioned raw material 2,5-hexanedione, 3-methyl-2-cyclopenten-1-one and target product methylcyclopentadiene are shown in Table 1.

Based on the above scheme, preferably, using 2,5-hexanedione or 3-methyl-2-cyclopenten-1-one as a raw material, in a fixed-bed continuous reactor, in a sedimentation precipitation method, a hydrothermal method Or under the action of AxByOz type composite metal oxide catalyst synthesized by citric acid complex method, through aldol condensation series hydrodeoxygenation reaction or direct hydrodeoxygenation reaction, at reaction temperature 300-600 ℃, hydrogen pressure 0.0001-1MPa ( Preferably 0.0001-0.9MPa, more preferably 0.0001-0.8MPa), the molar ratio of hydrogen to the substrate is 20-300:1, the mass space velocity of the substrate is 0.01-10h ^-1 (preferably 0.05-9h ^-1 , more preferably 0.1-8h ^-1 ), the target product of methylcyclopentadiene is obtained in one step.

Based on the above scheme, preferably, the AxByOz type composite metal oxide catalyst is prepared by a hydrothermal method, a deposition precipitation method or a citric acid complex method, and is subjected to reduction treatment in hydrogen before use, wherein the reduction condition is a hydrogen pressure of 0.001 -2.0MPa (preferably 0.005-1.5MPa, more preferably 0.01-1MPa), hydrogen flow rate 2-300mL/min (preferably 5-250mL/min, more preferably 10-200mL/min), reduction temperature 200-600°C (preferably 250 -550°C, more preferably 300-500°C), reduction time 0.5-12h (preferably 0.7-10h, more preferably 1-8h).

Based on the above scheme, preferably, the specific preparation process of the hydrothermal method is as follows: a certain amount of the metal salt of A and the metal salt of B are mixed and dissolved in deionized water, and the suspension is obtained by ultrasound at room temperature; In a stainless steel reaction kettle lined with tetrafluoroethylene, react at 80-220 °C for 5-48 hours, filter and wash the obtained powder, dry at 80 °C for 3 hours and then roast at 300-800 °C for 1-6 hours to obtain AxByOz type composite metal oxide catalyst.

Based on the above scheme, preferably, the AxByOz type composite metal oxide catalyst can also be synthesized by the deposition precipitation method, and the specific process is as follows: a certain amount of B metal salt is dissolved in deionized water, and the concentration is 0.5mol/L -14mol/L (preferably 1mol/L-8mol/L, more preferably 1.5mol/L-6mol/L) ammonia solution as a precipitant to adjust the pH value of the solution to be adjusted to 8-12, dropwise add the metal salt of A Aqueous solution, after stirring for 0.5-4h (preferably 1-3h), the obtained precipitate was filtered out, washed with deionized water and ethanol, dried in an oven at 100-200°C for 4-48h, and then dried at 300-800°C (preferably 350-750°C, more preferably 400-700°C) calcination for 0.5-10h (preferably 1-8h, more preferably 1-6h) to obtain AxByOz type composite metal oxide catalyst.

Based on the above scheme, preferably, the AxByOz type composite metal oxide catalyst can also be prepared by a citric acid complex method, and the specific process is: molar ratio M:citric acid=1:1-1:3 (preferably 1:1.05 -1:2, more preferably 1:1.1-1:1.5) Weigh the metal salt of B, the metal salt of A, citric acid, M is the molar sum of the metal B in the anion and the cationic metal A; After the ionized water is dissolved separately, the three solutions are mixed evenly, heated in an evaporating dish until only solids are formed; after drying at 120°C for 12 hours, the temperature is 300-800°C (preferably 350-750°C, more preferably 400-700°C) After calcination for 0.5-10h (preferably 1-8h, more preferably 1-6h), the AxByOz type composite metal oxide catalyst is obtained.

The method of the invention can synthesize the AxByOz type composite metal oxide catalyst in large quantities, and the preparation method is simple and the reaction conditions are mild. At the same time, after reduction of this type of catalyst, 2,5-hexanedione or 3-methyl-2-cyclopenten-1-one can be hydrodeoxygenated in series through aldol condensation in a fixed bed reactor without solvent. Reaction or direct hydrodeoxygenation reaction, one-step conversion to methylcyclopentadiene, few operation steps, high mass space velocity of substrate, high conversion efficiency, is a green and simple new synthetic route, which can be used for actual industrial production, Good catalytic performance.

The beneficial effects of the present invention are:

The present invention can not only use MCP as a substrate, but also can use 2,5-hexanedione, the source material for synthesizing MCP, as a substrate to prepare methylcyclopentadiene in one step, and the obtained target product has higher selectivity.

The present invention can synthesize a variety of AxByOz type composite metal oxides by using simple and easy-to-operate deposition precipitation method, hydrothermal method or citric acid complex method. In the reactor, 2,5-hexanedione or 3-methyl-2-cyclopenten-1-one is converted to 2,5-hexanedione or 3-methyl-2-cyclopenten-1-one through aldol condensation series hydrodeoxygenation reaction or direct hydrodeoxygenation reaction at a large mass space velocity in the reactor. One-step conversion into the target product methylcyclopentadiene.

The invention has the advantages of simple process route, environmental friendliness and simple catalyst preparation, and provides a brand-new catalytic method for the synthesis of methylcyclopentadiene.

The invention adopts a fixed-bed continuous flow reactor, and under the action of various AxByOz type composite metal oxide catalysts, 2,5-hexanedione or 3-methyl-2-cyclopenten-1-one can be converted in one step It is methylcyclopentadiene and has the advantages of simple process route, high conversion efficiency, large operability, low energy consumption, simple catalyst preparation and low environmental pollution.

Description of drawings

FIG. 1 is a gas chromatogram of the product of synthesizing methylcyclopentadiene from 2,5-hexanedione in Example 6. FIG.

FIG. 2 is a gas chromatogram of the product of synthesizing methylcyclopentadiene from 3-methyl-2-cyclopenten-1-one in Example 41. FIG.

Fig. 3 is the mass spectrometry comparison chart of the target product methylcyclopentadiene.

Figures 4-6 are XRD patterns of partially synthesized catalysts.

Figure 7 is the reaction pathway provided by the present invention.

Detailed ways

The technical solutions of the present invention are further described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to these embodiments.

Example 1

(1) Preparation of AxByOz type composite metal oxide catalyst CoMoO ₄ : Weigh 2.47 g of ammonium molybdate and dissolve it in 200 mL of deionized water. The pH value of the solution was adjusted to 9.5 by using an aqueous ammonia solution with a concentration of 2 mol/L as a precipitant, and an aqueous solution of cobalt nitrate (4.07 g dissolved in 100 mL of deionized water) was added dropwise. After stirring for 2 h, the obtained precipitate was filtered out. After washing with deionized water and ethanol, drying in an oven at 100 °C for 5 hours, and then calcining at 400 °C for 2 hours, the CoMoO ₄ composite metal oxide catalyst was obtained.

(2) 0.3 g of the above-mentioned CoMoO catalyst was uniformly mixed with ₄ mL of 40-70 mesh quartz sand, filled in a fixed-bed continuous reactor, and then at a hydrogen pressure of 0.2 MPa, a hydrogen flow of 90 mL/min, and a reduction temperature of 400 ° C. Reduction for 2h, then control the reaction temperature to 420°C, the reaction pressure to 0.05MPa, the hourly space velocity of 2,5-hexanedione to be 2h ^-1 , and the molar ratio of hydrogen to 2,5-hexanedione to be 70:1. The conversion of 5-hexanedione was 90% and the selectivity to methylcyclopentadiene was 80%.

Example 2

(1) AxByOz type composite metal oxide catalyst NiMoO ₄ can be prepared by citric acid complex method, and the specific process is as follows: Weigh 1.24 g of ammonium molybdate, 1.24 g of ammonium molybdate, Nickel nitrate 2.04g, citric acid 3.53g, M is the molar sum of metal B and cationic metal A in the anion; after dissolving with deionized water respectively, the three solutions are evenly mixed, and heated in an evaporating dish until only A solid is formed; after drying at 120°C for 12h and then calcining at 600°C for 5h, NiMoO ₄ catalyst is obtained.

(2) 0.3 g of the above-mentioned NiMoO catalyst was uniformly mixed with ₄ mL of 40-70 mesh quartz sand, filled in a fixed-bed continuous reactor, and then at a hydrogen pressure of 0.08 MPa, a hydrogen flow of 90 mL/min, and a reduction temperature of 400° C. Reduction was carried out for 2h, then the reaction temperature was controlled at 380°C, the reaction pressure was 0.05MPa, the hourly space velocity of 2,5-hexanedione was 2.3h ^-1 , the molar ratio of hydrogen to 2,5-hexanedione was 70:1, and the 2,5-hexanedione molar ratio was 70:1. , the conversion of 5-hexanedione was 90%, and the selectivity of methylcyclopentadiene was 84%.

Example 3

(1) Preparation of AxByOz-type composite metal oxide catalyst ZnMoO ₄ : Weigh 2.47 g of ammonium molybdate and dissolve it in 200 mL of deionized water. The pH value of the solution was adjusted to 8.9 by using an ammonia solution with a concentration of 2 mol/L as a precipitant, and then an aqueous solution of zinc nitrate (4.16 g dissolved in 100 mL of deionized water) was added dropwise, and after stirring for 2 h, the obtained precipitate was filtered out. After being washed with deionized water and ethanol, dried in an oven at 100 °C for 5 h, and then calcined at 400 °C for 2 h, the ZnMoO ₄ composite metal oxide catalyst was obtained.

(2) 0.2 g of the above-mentioned ZnMoO catalyst was uniformly mixed with ₄ mL of 40-70 mesh quartz sand, filled in a fixed-bed continuous reactor, and then at a hydrogen pressure of 0.05 MPa, a hydrogen flow of 150 mL/min, and a reduction temperature of 400 ° C. Reduction was carried out for 1 h, and then the reaction temperature was controlled at 400 °C, the reaction pressure was 0.05 MPa, the hourly space velocity of 2,5-hexanedione was 3 h ^-1 , and the molar ratio of hydrogen to 2,5-hexanedione was 70:1. The conversion of 5-hexanedione was 100% and the selectivity to methylcyclopentadiene was 89%.

Example 4

(1) AxByOz type composite metal oxide catalyst Cu ₃ Mo ₂ O ₉ can be prepared by hydrothermal method. The specific process is as follows: 0.50g of acetone acetate and 0.44g of ammonium molybdate tetrahydrate are dissolved in 40mL of deionized water, and ultrasonicated at room temperature. A suspension was obtained; the mixed solution was transferred to a stainless steel reaction kettle with a polytetrafluoroethylene lining, reacted at 120 °C for 12 hours, filtered and washed, and the obtained powder was dried at 80 °C for 3 hours and then calcined at 600 °C for 3 hours, namely A Cu ₃ Mo ₂ O ₉ catalyst can be obtained.

(2) 0.2 g of the above-mentioned Cu ₃ Mo ₂ O ₉ catalyst was uniformly mixed with 4 mL of 40-70 mesh quartz sand, filled in a fixed-bed continuous reactor, and then reduced at a hydrogen pressure of 0.05 MPa, a hydrogen flow of 150 mL/min, and reduced The reduction was carried out at a temperature of 400°C for 1 h, and then the reaction temperature was controlled to 400°C, the reaction pressure was 0.05MPa, the hourly space velocity of 2,5-hexanedione was 2.3h ^-1 , and the molar ratio of hydrogen to 2,5-hexanedione was 67: 1. The conversion of 2,5-hexanedione is 100%, and the selectivity of methylcyclopentadiene is 90%.

Example 5

(1) AxByOz type composite metal oxide catalyst Fe ₂ (MoO ₄ ) ₃ can be prepared by citric acid complexing method, and the specific process is as follows: molar ratio n(M)/n(citric acid)=1/1.2 to weigh molybdenum Ammonium acid 1.24g, ferric nitrate nonahydrate 1.89g, citric acid 2.94g, M is the molar sum of metal B and cationic metal A in the anion; after dissolving them in deionized water, the three solutions are evenly mixed, Heat in an evaporating dish until only solids are formed; after drying at 120°C for 12h, and calcining at 600°C for 5h, Fe ₂ (MoO ₄ ) ₃ catalyst is obtained.

(2) 0.3 g of the above-mentioned Fe ₂ (MoO ₄ ) ₃ catalyst was uniformly mixed with 4 mL of 40-70 mesh quartz sand, filled in a fixed-bed continuous reactor, and then at a hydrogen pressure of 0.08 MPa, a hydrogen flow of 120 mL/min, The reduction temperature was 400°C for 2h, and then the reaction temperature was controlled to 420°C, the reaction pressure was 0.05MPa, the hourly space velocity of 2,5-hexanedione was 2h ^-1 , and the molar ratio of hydrogen to 2,5-hexanedione was 90: 1, the conversion of 2,5-hexanedione is 93%, and the selectivity of methylcyclopentadiene is 86%.

Example 6

(1) The AxByOz type composite metal oxide catalyst NiWO ₄ can be prepared by a hydrothermal method. The specific process is as follows: 0.71 g of nickel acetate and 1.32 g of sodium tungstate dihydrate are dissolved in 80 mL of deionized water, and the suspension is obtained by ultrasound at room temperature; The mixed solution was transferred to a stainless steel reaction kettle with a Teflon lining, reacted at 120 °C for 12 h, filtered and washed, and the obtained powder was dried at 80 °C for 3 h and then calcined at 600 °C for 3 h to obtain NiWO ₄ catalyst.

(2) 0.25g of the above-mentioned NiWO ₄ catalyst was uniformly mixed with 4mL of 40-70 mesh quartz sand, filled in a fixed-bed continuous reactor, and then at a hydrogen pressure of 0.50MPa, a hydrogen flow rate of 160mL/min, and a reduction temperature of 450°C Reduction was carried out for 2.5h, then the reaction temperature was controlled at 400°C, the reaction pressure was 0.05MPa, the hourly space velocity of 2,5-hexanedione was 1.8h ^-1 , and the molar ratio of hydrogen to 2,5-hexanedione was 80:1. The conversion of 2,5-hexanedione was 96% and the selectivity to methylcyclopentadiene was 88%.

Example 7

(1) AxByOz type composite metal oxide catalyst Cr ₂ (MoO ₄ ) ₃ can be prepared by citric acid complexing method. The specific process is: molar ratio n(M)/n(citric acid)=1/1.2 to weigh molybdenum Ammonium acid 1.24g, chromium nitrate nonahydrate 1.87g, citric acid 2.94g, M is the molar sum of metal B and cationic metal A in the anion; after dissolving them in deionized water, the three solutions are evenly mixed, Heating in an evaporating dish until only solids are formed; after drying at 120°C for 12h and then calcining at 600°C for 5h, Cr ₂ (MoO ₄ ) ₃ catalyst is obtained.

(2) After mechanically mixing 0.1 g of the above-mentioned Cr ₂ (MoO ₄ ) ₃ catalyst and 0.2 g of the ZnMoO ₄ catalyst synthesized in Example 3, uniformly mixed with 4 mL of 40-70 mesh quartz sand, and filled in a fixed bed for continuous reaction In the reactor, the hydrogen pressure was 0.03MPa, the hydrogen flow rate was 150mL/min, and the reduction temperature was 400℃ for 2h, and then the reaction temperature was controlled to 400℃, the reaction pressure was 0.03MPa, and the hourly space velocity of 2,5-hexanedione was 2.5h ^{- 1.} The molar ratio of hydrogen to 2,5-hexanedione is 70:1, the conversion rate of 2,5-hexanedione is 100%, and the selectivity of methylcyclopentadiene is 92%.

The experimental results of the above-mentioned embodiments 1-7 are shown in Table 2.

Table 2 Synthesis of methylcyclopentadiene by hydrodeoxygenation of 2,5-hexanedione

Using Cr ₂ (MoO ₄ ) ₃ +ZnMoO ₄ in Example 7 as a catalyst, 0.2 g was uniformly mixed with 4 mL of 40-70 mesh quartz sand, filled in a fixed-bed continuous reactor, and 2,5-hexanedi Ketone was used as the substrate, and then reduced at a hydrogen pressure of 0.05 MPa and a reduction temperature of 400 °C for 1 h. The reaction was carried out under a certain molar ratio of hydrogen to 2,5-hexanedione, reaction temperature, reaction pressure and hourly space velocity.

Table 3 Cr ₂ (MoO ₄ ) ₃ +ZnMoO ₄ catalyzed the synthesis of methylcyclopentadiene by hydrodeoxygenation of 2,5-hexanedione

Example 24

(1) Preparation of AxByOz type composite metal oxide catalyst Zn ₃ Mo ₂ O ₉ : Weigh 2.47 g of ammonium molybdate and dissolve it in 200 mL of deionized water. The pH value of the solution was adjusted to 9.2 by using an ammonia solution with a concentration of 4 mol/L as a precipitant, and an aqueous solution of zinc nitrate (4.16 g dissolved in 100 mL of deionized water) was added dropwise. After stirring for 2 h, the obtained precipitate was filtered out. After washing with deionized water and ethanol, drying in an oven at 100°C for 5h, and then calcining at 400°C for 2h, the Zn ₃ Mo ₂ O ₉ composite metal oxide catalyst was obtained.

(2) 0.2 g of the above-mentioned Zn ₃ Mo ₂ O ₉ catalyst was uniformly mixed with 4 mL of 40-70 mesh quartz sand, filled in a fixed-bed continuous reactor, and then reduced under a hydrogen pressure of 0.05 MPa, a hydrogen flow of 150 mL/min, and a The reduction was performed at a temperature of 400°C for 1 hour, and then the reaction temperature was controlled to 400°C, the reaction pressure was 0.05MPa, the hourly space velocity of 3-methyl-2-cyclopenten-1-one was 3h ^-1 , and the hydrogen and 3-methyl-2 -The molar ratio of cyclopenten-1-one is 70:1, the conversion of 3-methyl-2-cyclopenten-1-one is 100%, and the selectivity of methylcyclopentadiene is 91% .

Example 25

(1) AxByOz type composite metal oxide catalyst CuMoO ₄ can be prepared by citric acid complexing method. The specific process is as follows: Weigh 1.24 g of ammonium molybdate, 1.24 g of ammonium molybdate, Copper nitrate 1.69g, citric acid 3.53g, M is the molar sum of metal B and cationic metal A in the anion; after dissolving them in deionized water, mix the solutions of the three evenly, and heat them in an evaporating dish until only A solid is formed; after drying at 120°C for 12h and then calcining at 600°C for 5h, the CuMoO ₄ catalyst is obtained.

(2) 0.15 g of the above-mentioned CuMoO catalyst was uniformly mixed with ₄ mL of 40-70 mesh quartz sand, filled in a fixed-bed continuous reactor, and then at a hydrogen pressure of 0.5 MPa, a hydrogen flow of 150 mL/min, and a reduction temperature of 400° C. Reduction for 2h, then control the reaction temperature to 400°C, the reaction pressure to 0.05MPa, the hourly space velocity of 3-methyl-2-cyclopenten-1-one to be 2.5h ^-1 , the hydrogen and 3-methyl-2-cyclopentene The molar ratio of -1-one was 70:1, the conversion of 3-methyl-2-cyclopenten-1-one was 100%, and the selectivity of methylcyclopentadiene was 82%.

Example 26

(1) AxByOz type composite metal oxide catalyst Zn ₃ (VO ₄ ) ₂ can be prepared by hydrothermal method. The specific process is as follows: dissolve 1.10g of zinc acetate and 0.47g of ammonium metavanadate in 60mL of deionized water, and sonicate at room temperature A suspension was obtained; the mixed solution was transferred to a stainless steel reaction kettle with a polytetrafluoroethylene lining, reacted at 120 °C for 12 hours, filtered and washed, and the obtained powder was dried at 80 °C for 3 hours and then calcined at 600 °C for 3 hours, namely Zn ₃ (VO ₄ ) ₂ catalyst can be obtained.

(2) 0.25 g of the above-mentioned Zn ₃ (VO ₄ ) ₂ catalyst was uniformly mixed with 4 mL of 40-70 mesh quartz sand, filled in a fixed-bed continuous reactor, and then at a hydrogen pressure of 0.50 MPa, a hydrogen flow of 160 mL/min, The reduction temperature was 450°C for 2.5h, and then the reaction temperature was controlled to 400°C, the reaction pressure was 0.05MPa, the hourly space velocity of 3-methyl-2-cyclopenten-1-one was 2.5h ^-1 , and the hydrogen and 3-methyl The molar ratio of -2-cyclopenten-1-one is 70:1, the conversion of 3-methyl-2-cyclopenten-1-one is 100%, and the selectivity of methylcyclopentadiene is 86%.

Example 27

(1) AxByOz type composite metal oxide catalyst MnMoO ₄ can be prepared by citric acid complex method. The specific process is as follows: Weigh 1.24 g of ammonium molybdate, 1.24 g of ammonium molybdate, 2.51 g of 50 wt% manganese nitrate aqueous solution, 3.53 g of citric acid, M is the molar sum of metal B and cationic metal A in the anion; after dissolving them in deionized water, the three solutions are evenly mixed, and placed in an evaporating dish. Heating until only solid is formed; after drying at 120°C for 12h, and calcining at 600°C for 5h, MnMoO ₄ catalyst is obtained.

(2) 0.5 g of the above-mentioned MnMoO catalyst was uniformly mixed with ₄ mL of 40-70 mesh quartz sand, filled in a fixed-bed continuous reactor, and then at a hydrogen pressure of 0.5 MPa, a hydrogen flow of 150 mL/min, and a reduction temperature of 400° C. Reduction for 2h, then control the reaction temperature to 400℃, the reaction pressure to 0.05MPa, the hourly space velocity of 3-methyl-2-cyclopenten-1-one to be 1.1h ^-1 , the hydrogen and 3-methyl-2-cyclopentene The molar ratio of -1-one was 70:1, the conversion of 3-methyl-2-cyclopenten-1-one was 100%, and the selectivity of methylcyclopentadiene was 89%.

Example 28

(1) AxByOz type composite metal oxide catalyst ZnWO ₄ can be prepared by hydrothermal method. The specific process is as follows: dissolve 0.55g zinc acetate and 0.99g sodium tungstate dihydrate in 60mL deionized water, and ultrasonically obtain a suspension at room temperature; The mixed solution was transferred to a stainless steel reaction kettle with a polytetrafluoroethylene lining, reacted at 120 °C for 12 hours, filtered and washed, and the obtained powder was dried at 80 °C for 3 hours and then calcined at 600 °C for 3 hours to obtain ZnWO ₄ catalyst.

(2) After mechanically mixing 0.1 g of the above-mentioned ZnWO ₄ catalyst with 0.1 g of the Zn ₃ Mo ₂ O ₉ catalyst synthesized in Example 8, uniformly mixed with 4 mL of 40-70 mesh quartz sand, and filled in a fixed-bed continuous reactor , and then reduced at a hydrogen pressure of 0.01 MPa, a hydrogen flow of 200 mL/min, and a reduction temperature of 450 °C for 1 h, and then controlled the reaction temperature to 400 °C and the reaction pressure of 0.01 MPa. The hourly space velocity is 3.5h ^-1 , the molar ratio of hydrogen to 3-methyl-2-cyclopenten-1-one is 100:1, and the conversion rate of 3-methyl-2-cyclopenten-1-one is is 100% and the selectivity to methylcyclopentadiene is 95%.

The experimental results of the above-mentioned Examples 24-28 are shown in Table 4.

Table 4 Synthesis of methylcyclopentadiene by hydrodeoxygenation of 3-methyl-2-cyclopenten-1-one

Using the ZnWO ₄ +Zn ₃ Mo ₂ O ₉ in Example 28 as the catalyst, 0.2 g was uniformly mixed with 4 mL of 40-70 mesh quartz sand, filled in a fixed-bed continuous reactor, and 2,5-hexanedione was used as the catalyst. As the substrate, and then reduced at a hydrogen pressure of 0.05 MPa and a reduction temperature of 400 ° C for 1 h, the reaction was carried out under a certain molar ratio of hydrogen to 2,5-hexanedione, reaction temperature, reaction pressure and hourly space velocity.

Table 5 Hydrodeoxygenation of methylcyclopentadiene from 3-methyl-2-cyclopenten-1-one catalyzed by ZnWO ₄ +Zn ₃ Mo ₂ O ₉

Claims (10)

1. a method for preparing methylcyclopentadiene, is characterized in that, described method comprises method 1 or method 2, and described method 1, method 2 paths are as follows: method 1

Method 2

The AxByOz type composite metal oxide catalyst includes: CuMoO ₄ , Cu ₃ Mo ₂ O ₉ , ZnMoO ₄ , Zn ₃ Mo ₂ O ₉ , NiMoO ₄ , CoMoO ₄ , MnMoO ₄ , FeMoO ₄ , Fe ₂ (MoO ₄ ) _3. One or more of Cr ₂ (MoO ₄ ) ₃ , CuWO ₄ , NiWO ₄ , CoWO ₄ , FeWO ₄ , ZnWO ₄ , and Zn ₃ (VO ₄ ) ₂ . 2. The method according to claim 1, wherein the reaction described in the method 1 or the method 2 is carried out in a fixed-bed continuous reactor; the reaction temperature is 300-600°C, the hydrogen pressure is 0.0001-1MPa, and the hydrogen The molar ratio to the substrate is 20-300:1, and the mass space velocity of the substrate is 0.01-10 h ^-1 . 3. The method according to claim 2, wherein the hydrogen pressure is 0.0001-0.9MPa; the mass space velocity of the substrate is 0.05-9h ^-1 . 4 . The method according to claim 3 , wherein the hydrogen pressure is 0.0001-0.8 MPa, and the mass space velocity of the substrate is 0.1-8 h ⁻¹ . 5 . 5. The method according to claim 1, wherein the AxByOz type composite metal oxide catalyst is prepared by a hydrothermal method, a deposition precipitation method or a citric acid complex method, and is subjected to reduction treatment in hydrogen before use, The reduction conditions are: hydrogen pressure 0.001-2.0MPa, hydrogen flow rate 2-300mL/min, reduction temperature 200-600°C, reduction time 0.5-12h. 6. The method according to claim 5, wherein the reduction conditions are: hydrogen pressure 0.005-1.5MPa, hydrogen flow rate 5-250mL/min, reduction temperature 250-550°C, reduction time 0.7-10h. 7. The method according to claim 6, wherein the hydrogen pressure is 0.01-1MPa, the hydrogen flow rate is 10-200mL/min, the reduction temperature is 300-500°C, and the reduction time is 1-8h. 8. The method of claim 5, wherein: The hydrothermal method includes the following steps: mixing and dissolving the metal salt of A and the metal salt of B in deionized water, and ultrasonically obtaining a suspension at room temperature; transferring the suspension to a reaction kettle, at 80-220° C. The reaction is carried out for 5-48h, then filtered and washed, dried at 80°C for 3h after washing, and then calcined at 300-800°C for 1-6h to obtain the AxByOz type composite metal oxide catalyst; The deposition and precipitation method comprises the following steps: dissolving the metal salt of B in deionized water, adjusting the pH value to 8-12 using an aqueous ammonia solution with a concentration of 0.5mol/L-14mol/L as a precipitating agent, adding dropwise the metal salt of A After stirring for 0.5-4h, the obtained precipitate was filtered out, washed with deionized water and ethanol, dried at 100-200°C for 4-48h, and then calcined at 300-800°C for 0.5-10h to obtain The AxByOz type composite metal oxide catalyst; The citric acid complex method comprises the following steps: weighing the metal salt of B, the metal salt of A and citric acid in a molar ratio of M:citric acid=1:1～1:3, where M is metal B and metal A After dissolving them in deionized water, the three solutions were evenly mixed, and heated in an evaporating dish until only solids were formed; after drying at 120°C for 12h, and calcining at 300-800°C for 0.5-10h, the obtained The AxByOz type composite metal oxide catalyst. 9. The method according to claim 8, characterized in that, In the deposition and precipitation method, the concentration of the ammonia solution is 1mol/L-8mol/L; the stirring time is 1-3h, the roasting temperature is 350-750°C, and the roasting time is 1-8h; In the citric acid complex method: the ratio of M:citric acid=1:1.05-1:2; the roasting temperature is 350-750°C; the roasting time is 1-8h. 10. The method of claim 9, wherein: In the deposition precipitation method: the concentration of the ammonia solution is 1.5mol/L-6mol/L; the roasting temperature is 400-700°C; the roasting time is 1-6h; In the citric acid complex method: the ratio of M:citric acid=1:1.1-1:1.5; the roasting temperature is 400-700°C, and the roasting time is 1-6h.

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