A dibenzofuran hydrodeoxygenation catalyst and a preparation method thereof

Abstract

The present application relates to coal tar upgrading technology field, and relates to a kind of dibenzofuran hydrogenation deoxidation catalyst and its preparation method.Hydrogenation deoxidation catalyst with amorphous alumina and magnesium oxide mixture as carrier, platinum and its oxide as active ingredient, wherein the mass ratio of alumina and magnesium oxide is 9:1, and active ingredient accounts for 0.1-3wt% of catalyst mass percentage;The carrier is prepared by coprecipitation method.Magnesium-aluminum mixed oxide carrier can improve the thermal stability of alumina material, and improve the life of catalyst at high temperature.Modified carrier inhibits the generation of deep hydrogenation by-product, improves BP selectivity;With high conversion rate, good selectivity and mild use condition and the like advantages, and good industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of coal tar hydrogenation and upgrading technology, specifically relating to a dibenzofuran hydrogenation deoxygenation catalyst and its preparation method. Background Technology

[0002] Coal liquefaction products typically contain a large amount of oxygen-containing organic compounds. Medium- and low-temperature coal tar has a high content of heteroatomic oxygen, resulting in low calorific value and poor stability, making it unsuitable for fuel. These compounds are usually phenols and furans. Phenolic substances can be separated and utilized industrially, while furans require hydrodeoxygenation to remove them or generate other high-value-added products. Dibenzofuran (DBF) is a typical furan compound, which can be hydrodeoxygenated to obtain high-value-added biphenyl (BP) or o-phenylphenol (OPP). Traditional Pt catalysts for the selective hydrodeoxygenation of dibenzofuran usually require high pressure and high temperature to improve reaction activity, and high catalyst stability is also required.

[0003] Wang L, Li C, Jin S, et al. Hydrodeoxygenation of dibenzofuran over SBA-15 supported Pt, Pd, and Ru catalysts[J]. Catalysis Letters, 2014, 144(5): 809-816. They used SBA-15 and noble metals to prepare a catalyst for the hydrogenation of dibenzofuran, but the preparation process was complicated and the reaction conditions were harsh.

[0004] Zhang Jie et al. (Zhang J, Wang L, Li C, et al. Selective Hydrogenolysis of dibenzofuran over highly efficient Pt / MgO catalysts to o-phenylphenol[J]. Organic Process Research & Development, 2018, 22(1):67-76.) investigated the hydrogenation reaction performance of Pt catalysts supported on acidic Al2O3, neutral SiO2, and basic MgO. Under reaction conditions of 400℃ and 1.0 MPa, the Pt catalyst supported on acidic Al2O3 mainly produced biphenyl and cyclohexylbenzene; while the catalysts supported on neutral SiO2 and basic MgO mainly produced o-phenylphenol.

[0005] Non-precious metals such as Ni (Peng Huwei. Study on the hydrodeoxygenation reaction of dibenzofuran catalyzed by Ni metal / ordered mesoporous SiO2-Al2O3 [D]. Taiyuan: Taiyuan University of Technology, 2018) are inexpensive but have disadvantages such as poor product selectivity and low product yield in continuous flow fixed bed hydrodeoxygenation.

[0006] CN103319313A describes a method for preparing biphenyl from dibenzofuran. Using dibenzofuran as a raw material and ethylene glycol dimethyl ether or diethylene glycol dimethyl ether as a solvent, metallic sodium is added to the reaction vessel, and the reaction is carried out under nitrogen protection to obtain o-phenylphenol. Due to the use of reactive metallic sodium, the process involves many steps, is relatively cumbersome, and poses certain risks.

[0007] CN106495991A describes a method for preparing biphenyl from dibenzofuran using a CoMo catalyst. This method employs a fixed-bed reactor to prepare biphenyl via hydrogenation refining of the catalyst, achieving a high selectivity (60%) for the biphenyl product.

[0008] CN104841421A describes a method for preparing biphenyl and o-phenylphenol from dibenzofuran using Pt and Pd catalysts. This method employs a fixed-bed reactor to prepare biphenyl and o-phenylphenol via hydrogenation purification of the catalyst; however, the selectivity for biphenyl is low, and the yield of o-phenylphenol is only 20%. Summary of the Invention

[0009] In view of this, the present invention provides a supported hydrodeoxygenation catalyst, its preparation method and application. The catalyst provided by the present invention has high selective hydrogenation activity for dibenzofuran and can obtain high-purity biphenyl products.

[0010] The first aspect of the present invention is to provide a dibenzofuran hydrodeoxygenation catalyst, wherein the hydrodeoxygenation catalyst uses a mixed oxide of amorphous alumina and magnesium oxide as a support, and platinum metal and its oxide as active components, wherein the mass ratio of alumina to magnesium oxide is 9:1, and the active components account for 0.1 to 3 wt% of the catalyst by mass percentage; the support is prepared by coprecipitation method.

[0011] The second aspect of the present invention is a first method for preparing the hydrodeoxygenation catalyst.

[0012] Step 1: Under continuous stirring at 30-60℃, slowly add the additive solution dropwise to the aluminum-magnesium mixed solution with pH < 7. When the pH of the reaction system is 7, stop adding the additive solution. After aging at 70-80℃ for 2-6 hours, the mixed oxide precursor solution is obtained.

[0013] Step 2: At 15–20°C, slowly add platinum solution and additives to the mixed oxide precursor solution, controlling the reaction system pH to be between 7 and 9 until the platinum solution is completely added. Continue adding additives and stop adding when the pH of the solution is adjusted to 9–10. Continue stirring and heating to 70–80°C, age for 2–6 hours to obtain a solid, and separate the solid from the solution.

[0014] Step 3: Dry the obtained solid at 80-120℃ for 10-12 hours, calcine at 400-900℃ for 3-6 hours, and then activate it in a tube furnace at 300-500℃ for 2-3 hours under a hydrogen atmosphere to finally obtain the hydrodeoxygenation catalyst.

[0015] The third aspect of the present invention is a second method for preparing the hydrodeoxygenation catalyst.

[0016] Step 1: Under continuous stirring at 30-60℃, slowly add the additive solution dropwise to the aluminum-magnesium-platinum mixed solution with pH < 7. When the pH of the reaction system is 9-10, stop adding the additive solution, continue stirring and heat to 70-80℃, age for 2-6 hours to obtain a solid, and separate the solid from the solution.

[0017] Step 2: Dry the obtained solid at 80-120℃ for 10-12 hours, calcine at 400-900℃ for 3-6 hours, and then activate it in a tube furnace at 300-500℃ for 2-3 hours under a hydrogen atmosphere to finally obtain the hydrodeoxygenation catalyst.

[0018] Furthermore, the concentration of metal ions in the aluminum-magnesium mixed solution is 1-5 mol / L. The aluminum-magnesium mixed solution is prepared by dissolving an aluminum source and a magnesium source in water or alcohol. The aluminum source is one or more of nano-alumina, aluminum chloride, sodium aluminate, or aluminum nitrate, preferably aluminum nitrate. The magnesium source is one or more of nano-magnesium oxide, magnesium chloride, magnesium oxalate, or magnesium nitrate, preferably magnesium nitrate.

[0019] Furthermore, the concentration of metal ions in the aluminum-magnesium-platinum mixed solution is 1–5 mol / L. The aluminum-magnesium-platinum mixed solution is prepared by dissolving an aluminum source, a magnesium source, and a platinum source in water or alcohol. The aluminum source is one or more of nano-alumina, aluminum chloride, sodium aluminate, or aluminum nitrate. The magnesium source is one or more of nano-magnesium oxide, magnesium chloride, magnesium oxalate, or magnesium nitrate. The platinum source is one or more of chloroplatinic acid, potassium chloroplatinate, ammonium hexachloroplatinate, potassium chloroplatinate, ammonium chloroplatinate, or platinum nitrate.

[0020] Furthermore, the solute in the auxiliary agent solution is one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide, or sodium aluminate, preferably sodium hydroxide, and the solvent is water, with a mass ratio of water to solute of 5 to 50:1.

[0021] Further, the platinum solution is a deionized water or alcohol solution of a platinum source acidified with nitric acid or hydrochloric acid, wherein the platinum source is one or more of chloroplatinic acid, potassium chloroplatinate, ammonium hexachloroplatinate, potassium chloroplatinate, ammonium chloroplatinate, or platinum nitrate, preferably platinum nitrate, and the platinum ion concentration is 10-1000 mg / L.

[0022] Furthermore, the tube furnace activation heating rate is 10℃ / min, the holding time is 1-2h, the carrier gas hydrogen flow rate is 10-30mL / min, and nitrogen protection cooling is subsequently used with a nitrogen flow rate of 10-30mL / min. The catalyst is then cooled and put into use.

[0023] The fourth aspect of this invention is a method for using the aforementioned hydrodeoxygenation catalyst, wherein the activated catalyst is pulverized, extruded, and molded to obtain the hydrodeoxygenation catalyst for use in a fixed-bed reactor. The weight hourly space velocity (WHSV) of the DBF / n-decane solution is 0.25 h⁻¹. -1 The hydrogenation reaction is carried out under the following process conditions: hydrogen-to-oil ratio of 400, reaction temperature of 320–330℃, and pressure of 0.1 MPa. It exhibits excellent selectivity.

[0024] The beneficial effects of this invention compared to the prior art are as follows:

[0025] Catalysts prepared using mixed oxides as support materials can increase the specific surface area of ​​the support, increase the number of active sites on the catalyst surface, and help these active sites to be more uniformly dispersed on the support surface, thereby improving the activity and efficiency of the catalyst. Furthermore, the addition of magnesium oxide can reduce carbon deposition on the catalyst under reaction conditions, improve selectivity, and reduce the deactivation rate during the reaction process. Attached Figure Description

[0026] Figure 1a The TEM image of the catalyst prepared in Example 1 is magnified 200,000 times.

[0027] Figure 1b The TEM image of the catalyst prepared in Example 1 is magnified 500,000 times.

[0028] Figure 2 The BET curve of the catalyst prepared in Example 1 is shown below.

[0029] Figure 3 The XRD patterns of the catalyst prepared in Example 1 are compared with those of Comparative Examples 1 and 2.

[0030] Figure 4 The H2-TPR diagrams of the catalyst prepared in Example 1 and Comparative Examples 1 and 2 are shown. Detailed Implementation

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] Weigh out 3.816 g of magnesium nitrate hexahydrate and 39.738 g of aluminum nitrate nonahydrate, and add 100 mL of deionized water to prepare a metal aqueous solution A; add an appropriate amount of dilute nitric acid to maintain the pH at acidic level for later use.

[0034] Weigh out 5.0g of sodium carbonate, 5.0g of sodium hydroxide, and 100mL of deionized water to prepare precipitant solution B for later use;

[0035] Solution A was added to the reactor, and the water bath temperature was maintained at 50°C while the electric stirrer was running at 300 rpm. While stirring, precipitant B was slowly added dropwise to the reactor. The pH value of the reaction solution was monitored using a pH meter and the pH of the reaction system was maintained at <7. The dropping rate was controlled by a metering pump during the dropping process, and the dropping rate was controlled at 2.0 mL / min. When the pH of the reaction system was 7, the dropping of solution B was stopped, the water bath temperature was increased to 75°C, and the reaction was carried out at a constant temperature for 3 hours to obtain emulsion C.

[0036] Prepare nitrate solution D by weighing 100 mg of platinum nitrate solid, 5 mL of 1M dilute nitric acid, and 20 mL of deionized water; store the solution at a temperature not exceeding 15℃ and keep it sealed away from light.

[0037] Maintain emulsion C at 15°C, and slowly add solution D to emulsion C using a metering pump; continue adding precipitant B to emulsion C using another metering pump; control the reaction system pH to be between 7 and 9 until solution D is completely added; continue adding precipitant B, and stop adding when the pH of emulsion C is adjusted to 9; control the metering pump dropping rate at 2.0 mL / min and the stirring rate at 300 rpm; raise the holding temperature to 75°C and age the reaction for 3 hours;

[0038] The reaction solution was filtered and washed, and the resulting solid E was placed in a forced-air drying oven and dried for 12 hours at a temperature of 80°C. The dried solid was then placed in a muffle furnace for calcination in an air atmosphere, heated to 450°C at a rate of 10°C / min, and held for 3 hours before being removed and cooled to obtain an unactivated hydrodeoxygenation catalyst, denoted as Pt / MA-19, with a mass ratio of alumina to magnesium oxide of 9:1.

[0039] The calcined solid was crushed and extruded into shape. The powder was sieved to 20-40 mesh and used for fixed-bed DBF hydrodeoxygenation reaction. Before use, the catalyst was activated in a tube furnace. The activation atmosphere was 10 mL / min H2, the temperature was increased to 300℃ at 10℃ / min, and the temperature was kept for 2 hours and then cooled to obtain the active Pt / MA-19 catalyst for later use.

[0040] 1 g of 20-40 mesh catalyst was placed in the middle of a stainless steel fixed-bed reactor, with 10-20 mesh quartz sand filling the sides; the weight hourly space velocity (WHSV) of the DBF / n-decane solution was 0.25 h⁻¹. -1 The hydrogenation reaction was carried out under the following process conditions: hydrogen-to-oil ratio of 400, reaction temperature of 320℃, and atmospheric pressure (0.1MPa).

[0041] The average DBF conversion rate in the Pt / MA-19 fixed-bed reactor was 88.6% within 4 hours, the BP selectivity was 98.8%, and the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 1.2%.

[0042] Example 2

[0043] The difference from Example 1 is as follows:

[0044] ① Weigh 0.7086g of magnesium chloride, 7.061g of aluminum chloride, and 50mL of deionized water to prepare a metal aqueous solution A; add an appropriate amount of dilute hydrochloric acid to maintain the pH at an acidic level for later use.

[0045] ②Weigh 64mg of potassium chloroplatinate solid, 5mL of 1M dilute hydrochloric acid, and 20mL of deionized water to prepare solution D; store the solution at a temperature not exceeding 15℃, and keep it sealed away from light.

[0046] The catalyst Pt / MA-19-Cl was obtained. Within 4 hours of fixed-bed reaction, the average DBF conversion rate was 72.1%, the BP selectivity was 92.3%, and the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 7.7%.

[0047] Example 3

[0048] Weigh out 3.816 g of magnesium nitrate hexahydrate, 39.738 g of aluminum nitrate nonahydrate, 100 mg of platinum nitrate solid, and 100 mL of deionized water to prepare a metal aqueous solution A; add an appropriate amount of dilute nitric acid to maintain the pH at an acidic level for later use; store the solution at a temperature not exceeding 15°C, and keep it sealed away from light;

[0049] Weigh out 5.0g of sodium carbonate, 5.0g of sodium hydroxide, and 100mL of deionized water to prepare precipitant solution B for later use;

[0050] Deionized water was added to the reactor, and the water bath was kept at 50°C with an electric stirrer at 300 rpm. Simultaneously, 100 mL of solution A and 50 mL of solution B were slowly added dropwise to the reactor while stirring. The dropping rate was controlled using a metering pump, with the rate maintained at 2.0 mL / min for solution A and 1.0 mL / min for solution B. After the addition was complete, the pH of the reaction solution was monitored using a pH meter, and solution B was used to maintain the pH of the reaction system at 9. The water bath temperature was then increased to 75°C, and the reaction was kept at this temperature for 5 hours to obtain emulsion C.

[0051] Emulsion C was filtered and washed, and the resulting solid E was placed in a forced-air drying oven and dried for 12 hours at a temperature of 80°C. The dried solid was then placed in a muffle furnace for calcination in an air atmosphere, heated to 450°C at a rate of 10°C / min, held for 3 hours, and then cooled to obtain an unactivated hydrodeoxygenation catalyst, denoted as Pt / MA-19-Col.

[0052] The calcined solid was crushed and extruded into shape. The powder was sieved to 20-40 mesh and used for fixed-bed DBF hydrodeoxygenation reaction. Before use, the catalyst was activated in a tube furnace. The activation atmosphere was 10 mL / min H2, the temperature was increased to 300℃ at 10℃ / min, and the temperature was kept for 2 hours and then cooled to obtain the active Pt / MA-19-Col catalyst for later use.

[0053] 1 g of 20-40 mesh catalyst was placed in the middle of a stainless steel fixed-bed reactor, with 10-20 mesh quartz sand filling the sides; the weight hourly space velocity (WHSV) of the DBF / n-decane solution was 0.25 h⁻¹. -1 The hydrogenation reaction was carried out under the process conditions of a hydrogen-to-oil ratio of 400, a reaction temperature of 320℃, and a pressure of 0.1MPa.

[0054] The average DBF conversion rate in the Pt / MA-19-Col fixed-bed reaction was 77.9% within 4 hours, the BP selectivity was 90.9%, and the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 9.1%.

[0055] Example 4

[0056] The difference from Example 6 is as follows:

[0057] Emulsion C was subjected to rotary evaporation to remove ethanol and water solvent. The rotary evaporation operation conditions were 30°C and 30 mmHg, replacing filtration and washing operations.

[0058] The average DBF conversion rate was 78.3% within 4 hours of the Pt / MA-19-Col-e fixed-bed reaction, the BP selectivity was 92.3%, and the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 7.7%.

[0059] Example 5

[0060] The difference from Example 6 is as follows:

[0061] ① Weigh 8.0g of sodium hydroxide and 100mL of deionized water to prepare precipitant solution B;

[0062] ② Add deionized water to the reactor, maintain the water bath temperature at 50℃, and stir with an electric stirrer at 300 rpm; while stirring, slowly add 100 mL of solution A and 30 mL of solution B to the reactor.

[0063] The average DBF conversion rate was 82.6% within 4 hours of the Pt / MA-19-Col-OH fixed-bed reaction, the BP selectivity was 98.8%, and the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 1.2%.

[0064] Example 6

[0065] The catalyst Pt / MA-19 from Example 1 was used;

[0066] 1 g of 20-40 mesh catalyst was placed in the middle of a stainless steel fixed-bed reactor, with 10-20 mesh quartz sand filling the sides; the weight hourly space velocity (WHSV) of the DBF / n-decane solution was 0.25 h⁻¹. -1 The hydrogenation reaction was carried out under the following process conditions: hydrogen-to-oil ratio of 400, reaction temperature of 350℃, and atmospheric pressure (0.1MPa).

[0067] The average DBF conversion rate in the Pt / MA-19 fixed-bed reactor was 89.7% within 4 hours, the BP selectivity was 91.2%, and the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 8.8%.

[0068] Comparative Example 1

[0069] Using the method of Example 1, without using magnesium nitrate hexahydrate, it is referred to as Comparative Example 1 Pt / Al2O3.

[0070] 1 g of 20-40 mesh catalyst was placed in the middle of a stainless steel fixed-bed reactor, with 10-20 mesh quartz sand filling the sides; the weight hourly space velocity (WHSV) of the DBF / n-decane solution was 0.25 h⁻¹. -1 The hydrogenation reaction was carried out under the process conditions of a hydrogen-to-oil ratio of 400, a reaction temperature of 320℃, and a pressure of 0.1MPa.

[0071] The average DBF conversion rate of the Pt / Al2O3 fixed-bed reaction was 73.1% within 4 hours, the BP selectivity was 71.4%, the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 17.0%, and the OPP selectivity was 11.6%.

[0072] Compared with Comparative Example 1, Example 1 has the advantages of high reactivity and high BP selectivity.

[0073] Comparative Example 2

[0074] Using the method of Example 1, without aluminum nitrate nonahydrate, it is referred to as Comparative Example 2Pt / MgO.

[0075] 1 g of 20-40 mesh catalyst was placed in the middle of a stainless steel fixed-bed reactor, with 10-20 mesh quartz sand filling the sides; the weight hourly space velocity (WHSV) of the DBF / n-decane solution was 0.25 h⁻¹. -1 The hydrogenation reaction was carried out under the process conditions of a hydrogen-to-oil ratio of 400, a reaction temperature of 320℃, and a pressure of 0.1MPa.

[0076] The average DBF conversion rate within 4 hours of the Pt / MgO fixed-bed reaction was 0%.

[0077] Compared with Comparative Example 2, Example 1 has the advantages of high reactivity and high BP selectivity.

[0078] Comparative Example 3

[0079] Using the method of Example 1, without aluminum nitrate nonahydrate, it is referred to as Comparative Example 3Pt / MgO.

[0080] 1 g of 20-40 mesh catalyst was placed in the middle of a stainless steel fixed-bed reactor, with 10-20 mesh quartz sand filling the sides; the weight hourly space velocity (WHSV) of the DBF / n-decane solution was 0.25 h⁻¹. -1 The hydrogenation reaction was carried out under the process conditions of a hydrogen-to-oil ratio of 400, a reaction temperature of 320℃, and a pressure of 1.0MPa.

[0081] The average DBF conversion rate in the Pt / MgO fixed-bed reaction was 70.1% within 4 hours, the BP selectivity was 58.9%, the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 22.3%, and the OPP selectivity was 18.8%.

[0082] Compared with Comparative Example 3, Example 1 has the advantage of mild reaction conditions.

[0083] Comparative Example 4

[0084] Weigh out 3.816 g of magnesium nitrate hexahydrate and 2.700 g of nano-alumina carrier; add 50 mL of anhydrous ethanol to the reactor and stir. After the magnesium nitrate dissolves, add the nano-alumina carrier and mix evenly; stir with an electric stirrer at 300 rpm and keep the water bath at 50 ℃; after removing the solvent methanol, the modified carrier MgO / Al2O3 is obtained.

[0085] Weigh 100 mg of platinum nitrate solid and 100 mL of deionized water to prepare a metal aqueous solution A; add an appropriate amount of dilute nitric acid to maintain the pH at an acidic level for later use; store the solution at a temperature not exceeding 15°C, and keep it sealed away from light;

[0086] Weigh out 5.0g of sodium carbonate, 5.0g of sodium hydroxide, and 100mL of deionized water to prepare precipitant solution B for later use;

[0087] Add 1g of carrier to the reactor, maintain the water bath temperature at 50℃, and stir with an electric stirrer at 300rpm. While stirring, slowly add 50mL of solution A and 50mL of anhydrous ethanol to the reactor. During the addition process, use a metering pump to control the dropping rate, which is maintained at 1.0mL / min. After the addition is complete, use a pH meter to monitor the pH value of the reaction solution, and use solution B to dropwise maintain the pH of the reaction system at 9-10. Raise the water bath temperature to 75℃ and age the reaction at this temperature for 5 hours to obtain emulsion C.

[0088] Emulsion C was subjected to rotary evaporation to remove ethanol and water solvent. The resulting solid E was placed in a forced-air drying oven and dried for 12 h. The rotary evaporation operation conditions were 30 °C and 30 mmHg. The temperature of the forced-air drying oven was 80 °C. The dried solid was placed in a muffle furnace for calcination in an air atmosphere. The temperature was increased to 450 °C at 10 °C / min and held for 3 h before being removed and cooled to obtain an unactivated hydrodeoxygenation catalyst, denoted as Pt / MgO / Al2O3-19-e.

[0089] The calcined solid was crushed and extruded into shape. The powder was sieved to 20-40 mesh and used for fixed-bed DBF hydrodeoxygenation reaction. Before use, the catalyst was activated in a tube furnace. The activation atmosphere was 10 mL / min H2, the temperature was increased to 300℃ at 10℃ / min, and the temperature was kept for 2 hours and then cooled to obtain the active Pt / MgO / Al2O3-19-e catalyst for later use.

[0090] Place 1g of 20-40 mesh catalyst in the middle of a stainless steel fixed-bed reactor, with 10-20 mesh quartz sand filling the sides; the weight hourly space velocity (WHSV) of the DBF / n-decane solution is 0.25h⁻¹. -1 The hydrogenation reaction was carried out under the process conditions of a hydrogen-to-oil ratio of 400, a reaction temperature of 320℃, and a pressure of 0.1MPa.

[0091] The average DBF conversion rate in the Pt / MgO / Al2O3-19-e fixed-bed reaction was 39.3% within 4 hours, the BP selectivity was 57.7%, and the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 42.3%.

[0092] Compared with Comparative Example 4, Example 1 has the advantages of high reactivity and BP selectivity;

[0093] Compared with Comparative Example 4, Example 1 has the advantage of high reaction stability.

[0094] Comparative Example 5

[0095] The difference from Example 1 is that the amount of magnesium nitrate hexahydrate is 7.632 g, the amount of aluminum nitrate nonahydrate is 35.323 g, and the catalyst Pt / MA-14 is obtained, with a mass ratio of aluminum oxide to magnesium oxide of 4:1.

[0096] The average DBF conversion rate in the Pt / MA-14 fixed-bed reactor was 16.3% within 4 hours, the BP selectivity was 69.9%, and the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 30.1%.

[0097] Comparative Example 6

[0098] The difference from Example 1 is that the amount of magnesium nitrate hexahydrate used is 12.593g, the amount of aluminum nitrate nonahydrate used is 29.141g, and the catalyst Pt / MA-12 is obtained, with the mass ratio of aluminum oxide to magnesium oxide being 2:1.

[0099] The average DBF conversion rate in the Pt / MA-12 fixed-bed reactor was 59.4% within 4 hours, the BP selectivity was 34.3%, the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 64.3%, and the OPP selectivity was 1.4%.

[0100] Comparative Example 7

[0101] The difference from Example 1 is that the amount of magnesium nitrate hexahydrate is 19.080 g, the amount of aluminum nitrate nonahydrate is 22.077 g, and the catalyst Pt / MA-11 is obtained, with the mass ratio of aluminum oxide to magnesium oxide being 1:1.

[0102] The average DBF conversion rate in the Pt / MA-11 fixed-bed reactor was 48.7% within 4 hours, the BP selectivity was 51.4%, the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 34.2%, and the OPP selectivity was 14.4%.

[0103] Comparative Example 8

[0104] The catalyst Pt / MA-19 from Example 1 was used;

[0105] 1 g of 20-40 mesh catalyst was placed in the middle of a stainless steel fixed-bed reactor, with 10-20 mesh quartz sand filling the sides; the weight hourly space velocity (WHSV) of the DBF / n-decane solution was 0.25 h⁻¹. -1 The hydrogenation reaction was carried out under the following process conditions: hydrogen-to-oil ratio of 400, reaction temperature of 250℃, and atmospheric pressure (0.1MPa).

[0106] The average DBF conversion rate in the Pt / MA-19 fixed-bed reactor was 37.4% within 4 hours, the BP selectivity was 42.0%, and the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 58.0%.

[0107] Comparative Example 9

[0108] The catalyst Pt / MA-19 from Example 1 was used;

[0109] Place 1g of 20-40 mesh catalyst in the middle of a stainless steel fixed-bed reactor, with 10-20 mesh quartz sand filling the sides; the weight hourly space velocity (WHSV) of the DBF / n-decane solution is 0.25h⁻¹. -1 The hydrogenation reaction was carried out under the following process conditions: hydrogen-to-oil ratio of 400, reaction temperature of 290℃, and atmospheric pressure (0.1MPa).

[0110] The average DBF conversion rate in the Pt / MA-19 fixed-bed reactor was 76.9% within 4 hours, the BP selectivity was 76.2%, and the selectivity for benzene, cyclohexane, and cyclohexylbenzene was 23.8%.

[0111] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a dibenzofuran hydrodeoxygenation catalyst, characterized in that: Step 1: Under continuous stirring at 30-60 ℃, slowly add the additive solution dropwise to the aluminum-magnesium mixed solution with pH < 7. When the pH of the reaction system reaches 7, stop adding the additive solution. After aging at 70-80 ℃ for 2-6 h, the mixed oxide precursor solution is obtained. Step 2: At 15-20 °C, slowly add platinum solution and additives to the mixed oxide precursor solution, controlling the reaction system pH to be 7 < pH < 9 until the platinum solution is completely added. Continue adding additives, and stop adding when the pH of the solution is adjusted to 9-10. Continue stirring and heating to 70-80 °C, and age for 2-6 hours to obtain a solid. Separate the solid from the solution. The solute in the additive solution is one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide, or sodium aluminate, and the solvent is water, with a water-to-solute mass ratio of 5-50:

1. Step 3: The obtained solid is dried at 80-120℃ for 10-12 hours, calcined at 400-900℃ for 3-6 hours, and then activated in a tube furnace at 300-500℃ for 2-3 hours under a hydrogen atmosphere to finally obtain a hydrodeoxygenation catalyst. The hydrodeoxygenation catalyst uses a mixed oxide of amorphous alumina and magnesium oxide as a support, and platinum metal and its oxides as active components. The mass ratio of alumina to magnesium oxide is 9:1, and the active component accounts for 0.1-3 wt% of the catalyst mass. The support is prepared by co-precipitation.

2. The preparation method according to claim 1, characterized in that: The concentration of metal ions in the aluminum-magnesium mixed solution is 1~5 mol / L. The aluminum-magnesium mixed solution is made by dissolving an aluminum source and a magnesium source in water or alcohol. The aluminum source is one or more of nano-alumina, aluminum chloride, sodium aluminate or aluminum nitrate. The magnesium source is one or more of nano-magnesium oxide, magnesium chloride, magnesium oxalate or magnesium nitrate.

3. The preparation method according to claim 1, characterized in that: The platinum solution is a deionized water or alcohol solution of a platinum source acidified with nitric acid or hydrochloric acid. The platinum source is one or more of chloroplatinic acid, potassium chloroplatinate, ammonium hexachloroplatinate, potassium chloroplatinate, ammonium chloroplatinate, or platinum nitrate, and the platinum ion concentration is 10 to 1000 mg / L.

4. A method for preparing a dibenzofuran hydrodeoxygenation catalyst, characterized in that: Step 1: Under continuous stirring at 30-60 ℃, the additive solution is slowly added dropwise to an aluminum-magnesium-platinum mixed solution with pH < 7. When the pH of the reaction system is 9-10, the addition of the additive solution is stopped, and the temperature is raised to 70-80 ℃ with continuous stirring. The mixture is aged for 2-6 hours to obtain a solid. The solid is then separated from the solution. The solute in the additive solution is one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide, or sodium aluminate, and the solvent is water, with a water-to-solute mass ratio of 5-50:

1. Step two: The obtained solid is dried at 80-120℃ for 10-12 h, calcined at 400-900℃ for 3-6 h, and then activated in a tube furnace at 300-500℃ for 2-3 h under a hydrogen atmosphere to finally obtain a hydrodeoxygenation catalyst. The hydrodeoxygenation catalyst uses a mixed oxide of amorphous alumina and magnesium oxide as a support, and platinum metal and its oxides as active components. The mass ratio of alumina to magnesium oxide is 9:1, and the active component accounts for 0.1-3 wt% of the catalyst mass. The support is prepared by co-precipitation.

5. The preparation method according to claim 4, characterized in that: The concentration of metal ions in the aluminum-magnesium-platinum mixed solution is 1~5 mol / L. The aluminum-magnesium-platinum mixed solution is prepared by dissolving an aluminum source, a magnesium source, and a platinum source in water or alcohol. The aluminum source is one or more of nano-alumina, aluminum chloride, sodium aluminate, or aluminum nitrate. The magnesium source is one or more of nano-magnesium oxide, magnesium chloride, magnesium oxalate, or magnesium nitrate. The platinum source is one or more of chloroplatinic acid, potassium chloroplatinate, ammonium hexachloroplatinate, potassium chloroplatinate, ammonium chloroplatinate, or platinum nitrate.

6. The method for applying the hydrodeoxygenation catalyst prepared by the method according to claim 1, characterized in that: The catalyst was placed in a fixed-bed reactor, and the weight hourly space velocity (WHSV) of the DBF / n-decane solution was 0.25 h⁻¹. -1 The hydrogenation reaction was carried out under the following process conditions: hydrogen-to-oil ratio of 400, reaction temperature of 320-330℃, and pressure of 0.1 MPa.

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