Method for preparing alkyl naphthalene by using metal organic framework as catalyst and application of alkyl naphthalene

Abstract

The invention provides a method for preparing alkyl naphthalene by using a metal organic framework as a catalyst and application of the alkyl naphthalene. The method comprises the following step: in the presence of a metal organic framework catalyst, alpha-olefin and naphthalene and / or methylnaphthalene are subjected to an alkylation reaction to obtain alkyl naphthalene. The invention also provides application of the alkyl naphthalene prepared by the method for preparing the alkyl naphthalene by using the metal organic framework as the catalyst as base oil of V-type lubricating oil. The alkyl naphthalene is prepared by adopting the MOFs catalyst, the catalyst has large pore channels, and the catalyst is high in catalytic activity, long in service life, free of pollution and not prone to corroding equipment in the preparation process of the alkyl naphthalene.

Description

Technical Field

[0001] The invention relates to a method for preparing alkyl naphthalene by using a metal organic framework as a catalyst and application thereof, belonging to the technical field of alkyl naphthalene base oil. Background Art

[0002] Alkyl naphthalene base oil (ANs) is an alkylated aromatic hydrocarbon prepared by introducing alkyl groups on the naphthalene ring through an alkylation process using long-chain alpha olefins (C8-C20) and naphthalene as raw materials. It belongs to a type of Class V lubricant base oil. At present, alkyl naphthalene can be used as a base oil in hydraulic oil, gear oil, heat transfer oil, compressor oil and other fields. Alkyl naphthalene base oil is mainly used as a high-efficiency blending component of Class II, Class III and Class IV high-grade base oils, which can significantly improve the heat resistance, thermal oxidation stability, solubility, dispersibility, additive sensitivity, rubber compatibility, volatility and hydrolysis stability of oil products, thereby extending the service life of these high-end lubricants. As mechanical equipment develops towards heavy loads and high speeds, the demand for alkyl naphthalene base oils with excellent thermal stability and oxidation stability is increasing, and the global alkyl naphthalene base oil is in short supply. Therefore, the production of alkyl naphthalene base oil is of great significance to the development of the lubricant industry.

[0003] At present, liquid acids (concentrated sulfuric acid, hydrofluoric acid, trifluoromethanesulfonic acid, etc.) and solid acids (AlCl3, molecular sieves, etc.) are mainly used as catalysts for the production of alkyl naphthalene in industry, among which concentrated sulfuric acid and hydrofluoric acid are already mature in industrial applications. However, these technologies have problems such as equipment corrosion, environmental pollution and easy deactivation of catalysts. Therefore, the development of a catalyst that is not easy to corrode equipment, is green and environmentally friendly, and has a long life is the key to this technology.

[0004] CN113388430A discloses a method for preparing alkylnaphthalene from mixed olefins. The method comprises the following steps: mixing mixed α-olefins and naphthalene, adding a solid acid catalyst and a solvent, and reacting at high temperature to obtain a product. The method adopts a solid acid catalyst, which solves the problem that the performance of alkylnaphthalene prepared by using mixed olefins as raw materials in the prior art is difficult to reach the performance index of alkylnaphthalene prepared by using single carbon number olefins, and also solves the problem that liquid catalysts corrode equipment, are not environmentally friendly, and the cost of raw material olefins is high in the prior art. However, when the solid acid catalyst is used for a long time, the polymer will still block the catalyst pores and cause the catalyst to deactivate.

[0005] CN109824467A discloses a method for preparing polyalkylnaphthalene using ionic liquid catalysis. The method comprises the following steps: (1) preparing an ionic liquid catalyst with an acidic calculated amount of X; (2) first adding naphthalene to the ionic liquid catalyst prepared in step (1) according to a molar ratio of naphthalene to olefin of 1:1-1:10, and then slowly dripping the olefin into the mixture; (3) after the reaction is completed, cooling the mixture to room temperature and layering, washing the upper liquid product with water to remove a small amount of ionic liquid, and then removing the inert organic solvent and residual naphthalene by reduced pressure distillation, and then extracting the liquid in the flask for multiple times to obtain a polyalkylnaphthalene product. The reaction system in the method is a mixture of naphthalene, medium- and long-chain α-olefins, and ionic liquid catalysts. The method overcomes the shortcomings of traditional alkylation catalysts that pollute the environment, are highly toxic, and are highly corrosive. However, due to the complex preparation process and high cost of ionic liquid catalysts, they are not suitable for industrial production.

[0006] CN114507110A discloses a method for producing alkylnaphthalene. The method uses trifluoromethanesulfonic acid and / or methanesulfonic acid as a catalyst, naphthalene and olefin as raw materials, and naphthalene, olefin and catalyst are mixed and reacted to obtain alkylnaphthalene. The method solves the problems of short catalyst service life and difficult post-processing. However, since the method uses trifluoromethanesulfonic acid and / or methanesulfonic acid as a catalyst, it is easy to corrode equipment and does not conform to the concept of green environmental protection.

[0007] CN104817419A discloses a method for preparing alkylnaphthalene and its application. The method comprises the following steps: in the presence of a gallium trifluoromethanesulfonate catalyst, naphthalene or α-methylnaphthalene or a mixture of naphthalene and α-methylnaphthalene is subjected to an alkylation reaction with a C4-C22 α-olefin to generate an alkylnaphthalene product. The product alkylnaphthalene contains one or more C4-C22 alkyl substituents that are the same or different from each other. The catalyst used in the method is prone to corrode equipment and causes great environmental pollution.

[0008] In summary, the existing alkylnaphthalene synthesis methods have the disadvantages of easy corrosion of catalysts, environmental pollution, complex catalyst preparation process and short catalyst life. Therefore, developing a new method for preparing alkylnaphthalene is still one of the problems to be solved in the art. Summary of the invention

[0009] In order to solve the above technical problems, the purpose of the present invention is to provide a method for preparing alkyl naphthalene using a metal organic framework as a catalyst and its application. The present invention uses a MOFs catalyst to prepare alkyl naphthalene, and the catalyst has large pores. In the preparation process of alkyl naphthalene, the catalyst has high catalytic activity, long service life, no pollution, and is not easy to corrode equipment.

[0010] In order to achieve the above object, the first aspect of the present invention provides a method for preparing alkylnaphthalene using a metal organic framework as a catalyst, which comprises the following steps:

[0011] In the presence of a metal organic framework (MOFs) catalyst, α-olefin and naphthalene and / or methylnaphthalene are subjected to an alkylation reaction to obtain the alkylnaphthalene;

[0012] The metal organic framework catalyst is prepared by at least the following steps: mixing an inorganic metal salt and an organic ligand in a first solvent to obtain a mixed solution, wherein the inorganic metal salt includes one or a combination of chromium salts, zirconium salts and aluminum salts; reacting the mixed solution for a first time under a first temperature condition to obtain a reaction product; and subjecting the reaction product to solid-liquid separation, washing and drying to obtain the metal organic framework catalyst.

[0013] According to some specific embodiments of the present invention, the alkylation reaction is carried out in the presence of a solvent. Preferably, the solvent comprises one or a combination of C6-C14 normal alkanes. The amount of the solvent can be conventionally adjusted by a person skilled in the art.

[0014] According to some specific embodiments of the present invention, preferably, the α-olefin includes one or a combination of several C8-C20 long-chain α-olefins.

[0015] According to some specific embodiments of the present invention, the methylnaphthalene may include α-methylnaphthalene and / or β-methylnaphthalene.

[0016] According to some specific embodiments of the present invention, preferably, the molar ratio of naphthalene and / or methylnaphthalene:α-olefin is (0.5-5):1.

[0017] According to some specific embodiments of the present invention, preferably, the mass ratio of the metal organic framework catalyst: α-olefin and naphthalene and / or methylnaphthalene is (0.01-0.1):1.

[0018] According to some specific embodiments of the present invention, preferably, the alkylation reaction is carried out at a temperature of 80-150° C., at a pressure of normal pressure, and for a time of 0.5-24 h.

[0019] According to some specific embodiments of the present invention, preferably, the method further comprises the following steps: after the alkylation reaction is completed, the reaction mixture is washed to remove the catalyst, then decolorized, and then distilled under reduced pressure to obtain the alkyl naphthalene.

[0020] In some specific embodiments of the present invention, the decolorization treatment may include: mixing a decolorizing agent with the washed product, decolorizing the product, and obtaining a decolorized product after filtering or suction filtration. Preferably, the decolorizing agent includes activated carbon and / or activated clay. The mixing ratio of the decolorizing agent and the washed product can be conventionally adjusted by those skilled in the art, for example, the amount of the decolorizing agent can be 0.1%-0.5% of the mass of the washed product. The decolorization process can be carried out under stirring conditions, the temperature can be 60-100°C, and the stirring time can be 0.5-2h.

[0021] In some specific embodiments of the present invention, the temperature of the reduced pressure distillation is 70°C-200°C, and the pressure is -99 kPa to 0 kPa.

[0022] According to some specific embodiments of the present invention, preferably, in the step of preparing the metal organic framework catalyst, the chromium salt includes one or a combination of chromium nitrate, chromium sulfate and chromium chloride.

[0023] According to some specific embodiments of the present invention, preferably, in the step of preparing the metal organic framework catalyst, the zirconium salt includes one or a combination of zirconium nitrate, zirconium sulfate and zirconium chloride.

[0024] According to some specific embodiments of the present invention, preferably, in the step of preparing the metal organic framework catalyst, the aluminum salt includes one or a combination of aluminum nitrate, aluminum sulfate and aluminum chloride.

[0025] According to some specific embodiments of the present invention, preferably, the inorganic metal salt includes a chromium salt and a zirconium salt, or a zirconium salt and an aluminum salt, or a chromium salt and an aluminum salt, or a chromium salt, a zirconium salt and an aluminum salt. Wherein, when a combination of a chromium salt and a zirconium salt is used, the molar ratio of the chromium salt and the zirconium salt may be 1: (0.5-2), preferably 1: 1. When a combination of a zirconium salt and an aluminum salt is used, the molar ratio of the zirconium salt and the aluminum salt may be 1: (0.5-2), preferably 1: 1. When a combination of a chromium salt and an aluminum salt is used, the molar ratio of the chromium salt and the aluminum salt may be 1: (0.5-2), preferably 1: 1. When a combination of a chromium salt, a zirconium salt and an aluminum salt is used, the molar ratio of the chromium salt, the zirconium salt and the aluminum salt may be 1: (0.5-2): (0.5-2), preferably 1: 1: 1.

[0026] According to some specific embodiments of the present invention, preferably, in the step of preparing the metal organic framework catalyst, the organic ligand comprises terephthalic acid.

[0027] According to some specific embodiments of the present invention, preferably, in the step of preparing the metal organic framework catalyst, the molar ratio of the organic ligand to the metal in the inorganic metal salt is 1:(0.5-4).

[0028] According to some specific embodiments of the present invention, preferably, in the step of preparing the metal organic framework catalyst, the first solvent comprises N,N-dimethylformamide. The amount of the first solvent can be conventionally adjusted by those skilled in the art.

[0029] According to some specific embodiments of the present invention, preferably, in the step of preparing the metal organic framework catalyst, the mixed solution is obtained by mixing an inorganic metal salt and an organic ligand in a first solvent and dissolving them by ultrasonication. The power, frequency and time of the ultrasonic wave can be conventionally adjusted by a person skilled in the art.

[0030] According to some specific embodiments of the present invention, preferably, in the step of preparing the metal organic framework catalyst, the first temperature is 80-150° C., and the first time is 12-72 h.

[0031] In some specific embodiments of the present invention, in the preparation step of the metal organic framework catalyst, the solid-liquid separation, washing and drying of the reaction product can be carried out according to conventional methods in the art, and the present invention does not specifically limit them.

[0032] According to some specific embodiments of the present invention, preferably, the specific surface area of ​​the metal organic framework catalyst is 1000-2000m 2 / gThe average pore size is 0.5-1.5nm.

[0033] According to some specific embodiments of the present invention, preferably, the pore volume of the metal organic framework catalyst is 0.5-2cm 2 / g.

[0034] The second aspect of the present invention provides the use of alkyl naphthalene prepared by the above-mentioned method for preparing alkyl naphthalene using a metal organic framework as a catalyst as a Class V lubricant base oil.

[0035] According to some specific embodiments of the present invention, the 100°C kinematic viscosity of the alkyl naphthalene prepared by the method of the present invention is 4-41 mm 2 / s, 40℃ kinematic viscosity is 10-500mm 2 / s, viscosity index is 70-130, pour point is -20℃ to -60℃, flash point is 180℃-250℃, all of which meet the requirements for lubricating oil base oil in this field and can be directly used as Class V lubricating oil base oil.

[0036] At present, the catalysts for synthesizing alkylnaphthalene in industry usually adopt liquid acid (concentrated sulfuric acid, hydrofluoric acid, trifluoromethanesulfonic acid, etc.) catalysts and traditional solid acid (AlCl3, molecular sieve, etc.) catalysts. However, traditional liquid acid catalysts have problems such as corrosion of equipment and environmental pollution. Acidic ion liquid catalyst is a new type of liquid acid catalyst for synthesizing alkylnaphthalene, but it still has the disadvantages of complex production process, corrosion of equipment and environmental pollution. Although solid acid catalysts can overcome these problems, due to the small pores of solid acid, the pores of catalyst are easy to be blocked during long-term operation, resulting in catalyst deactivation.

[0037] The technical solution of the present invention has at least the following beneficial effects:

[0038] (1) The metal organic framework (MOFs) catalyst synthesized in the present invention has large pores and is not easily deactivated due to pore blockage during long-term operation. Therefore, the catalyst of the present invention has a long lifespan, which can reach more than 100 hours.

[0039] (2) The present invention uses a metal organic framework catalyst to catalyze the alkylation reaction of long-chain α-olefins with naphthalene and / or methylnaphthalene, and has high catalytic activity. Under mild reaction conditions, the conversion rate of naphthalene and / or methylnaphthalene is higher than 98%.

[0040] (3) The metal organic framework catalyst of the present invention is not easy to corrode equipment and will not pollute the environment.

[0041] In summary, the present invention provides a method for preparing alkylnaphthalene using a metal organic framework as a catalyst and its application. The present invention synthesizes MOFs material by a hydrothermal method, the synthesis method is simple, and the prepared acidic MOFs material has a high specific surface area and a large pore size. The present invention is the first to use MOFs as a catalyst for the preparation of alkylnaphthalene. The MOFs catalyst of the present invention has the advantages of high catalytic activity, long life, no pollution, and not easy to corrode equipment in the preparation process of alkylnaphthalene, breaking the constraints of existing liquid acid catalysts and solid acid catalysts, and solving the problems of equipment corrosion, environmental pollution and easy deactivation of catalysts in these catalysts. The method provided by the present invention can efficiently catalyze the synthesis of alkylnaphthalene from long-chain α-olefins, the catalyst life can reach more than 100h, and the conversion rate of naphthalene and / or methylnaphthalene is higher than 98%. The present invention broadens the types of catalysts for synthesizing alkylnaphthalene, and the catalyst can be widely used in the reaction of various olefins and naphthalene, and has a wide applicability and high industrial application value. The alkyl naphthalene product prepared by the present invention has excellent physical and chemical properties, such as viscosity, flash point, pour point, etc., meets the requirements of the lubricating oil base oil in the field, and can be directly used as Class V lubricating oil base oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1This is the XRD pattern of MOFs catalyst A in Example 1. DETAILED DESCRIPTION

[0043] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0044] In the following examples and comparative examples, the conversion of naphthalene and / or methylnaphthalene is obtained by gas chromatography-mass spectrometry (GC-MS) analysis. The kinematic viscosity of the alkylnaphthalene product at 40°C and 100°C is determined according to GB / T265, the viscosity index is determined according to GB / T1995, the pour point is determined according to GB / T3535, and the flash point is determined according to GB / T3536. The average pore size and specific surface area of ​​the MOFs catalyst are determined by a physical adsorption instrument.

[0045] Example 1

[0046] This embodiment provides a method for preparing alkylnaphthalene using a metal organic framework as a catalyst, which comprises the following steps:

[0047] (1) Preparation of MOFs catalyst A

[0048] 1.60 g Cr(NO3)3·9H2O (0.004 mol) and 0.33 g terephthalic acid (0.002 mol) were dissolved in 40 mL N,N-dimethylformamide, placed in a sealed flask, and the raw materials were completely dissolved by ultrasound to obtain a mixed solution; the mixed solution was transferred into a 50 mL reactor, and the reactor was placed in an electric heated blast drying oven, and the reaction was carried out at 120°C for 24 hours to obtain a reaction product; the reaction product was allowed to cool naturally at room temperature, and after solid-liquid separation, the product was repeatedly washed 3-4 times with N,N-dimethylformamide, and then placed in a drying oven at 80°C for 12 hours to obtain a white solid powder, which is MOFs catalyst A;

[0049] (2) Alkylation of naphthalene using MOFs catalyst A

[0050] 25.63 g of naphthalene and 0.59 g of MOFs catalyst A were added to a three-necked flask equipped with a stirrer and a reflux condenser, and then 60 mL of n-decane was added. The three-necked flask was placed in an oil bath for heating and the stirrer was turned on. Then, a total of 33.66 g of dodecene was added in small amounts and multiple times. After the temperature of the reaction system reached 80°C, the reaction was stirred at a constant temperature for 2 hours. When the reaction was completed, the heating was stopped.

[0051] The reaction mixture is washed with water to remove the catalyst; then 0.1% by weight of activated clay is added to the washed product, stirred at 80° C. for 1 hour, and filtered to obtain a decolorized product; the decolorized product is subjected to reduced pressure distillation at 160° C. and -99 kPa to remove the solvent and unreacted raw materials to obtain a long-chain alkyl naphthalene product.

[0052] The average pore size of MOFs catalyst A in this example is 1 nm, and the specific surface area is 1486 m 2 / g. The XRD pattern of the MOFs catalyst A is shown in Figure 1 As shown by Figure 1 It can be seen that the target catalyst was prepared in this example.

[0053] The long-chain alkyl naphthalene product of this embodiment was analyzed by GC-MS, and the conversion rate of naphthalene was shown in Table 1. The kinematic viscosity at 100°C, kinematic viscosity at 40°C, viscosity index, pour point and flash point of the long-chain alkyl naphthalene product of this embodiment are shown in Table 1.

[0054] Example 2

[0055] This embodiment provides a method for preparing alkylnaphthalene using a metal organic framework as a catalyst, which comprises the following steps:

[0056] (1) Preparation of MOFs catalyst B

[0057] 0.43g Zr(NO3)4·5H2O (0.001mol) and 0.33g terephthalic acid (0.002mol) were dissolved in 40mL N,N-dimethylformamide, placed in a sealed flask, and the raw materials were completely dissolved by ultrasound to obtain a mixed solution; the mixed solution was transferred into a 50mL reactor, and the reactor was placed in an electric heated blast drying oven, and the reaction was carried out at 80°C for 12h to obtain a reaction product; the reaction product was allowed to cool naturally at room temperature, and after solid-liquid separation, the product was repeatedly washed 3-4 times with N,N-dimethylformamide, and then placed in a drying oven at 80°C and dried for 12h to obtain a white solid powder, which is MOFs catalyst B;

[0058] (2) Alkylation of naphthalene using MOFs catalyst B

[0059] 12.81 g of naphthalene and 0.93 g of MOFs catalyst B were added to a three-necked flask equipped with a stirrer and a reflux condenser, and 46 mL of n-decane was added. The three-necked flask was placed in an oil bath for heating and the stirrer was turned on. Then, a total of 33.66 g of dodecene was added in small amounts and multiple times. After the temperature of the reaction system reached 90° C., the reaction was stirred at a constant temperature for 12 h. When the reaction was completed, the heating was stopped.

[0060] The reaction mixture is washed with water to remove the catalyst; then 0.1% by weight of activated clay is added to the washed product, stirred at 80° C. for 1 hour, and filtered to obtain a decolorized product; the decolorized product is subjected to reduced pressure distillation at 70° C. and 0 kPa to remove the solvent and unreacted raw materials to obtain a long-chain alkyl naphthalene product.

[0061] The average pore size of MOFs catalyst B in this example is 1.1 nm, and the specific surface area is 1543 m 2 / g.

[0062] The long-chain alkyl naphthalene product of this embodiment was analyzed by GC-MS, and the conversion rate of naphthalene was shown in Table 1. The kinematic viscosity at 100°C, kinematic viscosity at 40°C, viscosity index, pour point and flash point of the long-chain alkyl naphthalene product of this embodiment are shown in Table 1.

[0063] Example 3

[0064] This embodiment provides a method for preparing alkylnaphthalene using a metal organic framework as a catalyst, which comprises the following steps:

[0065] (1) Preparation of MOFs catalyst C

[0066] 2.99g Al(NO3)3·9H2O (0.008mol) and 0.33g terephthalic acid (0.002mol) were dissolved in 40mL N,N-dimethylformamide, placed in a sealed flask, and the raw materials were completely dissolved by ultrasound to obtain a mixed solution; the mixed solution was transferred into a 50mL reactor, and the reactor was placed in an electric heated blast drying oven, and the reaction was carried out at 150°C for 72h to obtain a reaction product; the reaction product was allowed to cool naturally at room temperature, and after solid-liquid separation, the product was repeatedly washed 3-4 times with N,N-dimethylformamide, and then placed in a drying oven at 80°C and dried for 12h to obtain a white solid powder, which is MOFs catalyst C;

[0067] (2) Alkylation of naphthalene using MOFs catalyst C

[0068] 51.27 g of naphthalene and 8.49 g of MOFs catalyst C were added to a three-necked flask equipped with a stirrer and a reflux condenser, and then 85 mL of n-hexane was added. The three-necked flask was placed in an oil bath for heating and the stirrer was turned on. Then, a total of 33.66 g of dodecene was added in small amounts and multiple times. After the temperature of the reaction system reached 100° C., the reaction was stirred at a constant temperature for 24 hours. When the reaction was completed, the heating was stopped.

[0069] The reaction mixture is washed with water to remove the catalyst; then 0.1% by weight of activated clay is added to the washed product, stirred at 80° C. for 1 hour, and filtered to obtain a decolorized product; the decolorized product is subjected to reduced pressure distillation at 200° C. and -10 kPa to remove the solvent and unreacted raw materials to obtain a long-chain alkyl naphthalene product.

[0070] The average pore size of the MOFs catalyst C in this example is 0.5 nm, and the specific surface area is 1005 m 2 / g.

[0071] The long-chain alkyl naphthalene product of this embodiment was analyzed by GC-MS, and the conversion rate of naphthalene was shown in Table 1. The kinematic viscosity at 100°C, kinematic viscosity at 40°C, viscosity index, pour point and flash point of the long-chain alkyl naphthalene product of this embodiment are shown in Table 1.

[0072] Example 4

[0073] This embodiment provides a method for preparing alkylnaphthalene using a metal organic framework as a catalyst, which comprises the following steps:

[0074] (1) Preparation of MOFs catalyst D

[0075] 4.29 g Zr(NO3)4·5H2O (0.01 mol) and 0.66 g terephthalic acid (0.004 mol) were dissolved in 40 mL N,N-dimethylformamide, placed in a sealed flask, and the raw materials were completely dissolved by ultrasound to obtain a mixed solution; the mixed solution was transferred into a 50 mL reactor, and the reactor was placed in an electric heated blast drying oven, and the reaction was carried out at 135°C for 30 hours to obtain a reaction product; the reaction product was allowed to cool naturally at room temperature, and after solid-liquid separation, the product was repeatedly washed 3-4 times with N,N-dimethylformamide, and then placed in a drying oven at 80°C and dried for 12 hours to obtain a white solid powder, which is MOFs catalyst D;

[0076] (2) Alkylation of methylnaphthalene using MOFs catalyst D

[0077] 51.27 g of α-methylnaphthalene and 4.24 g of MOFs catalyst D were added to a three-necked flask equipped with a stirrer and a reflux condenser, and then 84 mL of tetradecane was added. The three-necked flask was placed in an oil bath for heating and the stirrer was turned on. Then, a total of 33.66 g of dodecene was added in small amounts and multiple times. After the temperature of the reaction system reached 120°C, the reaction was stirred at a constant temperature for 0.5 h. When the reaction was completed, the heating was stopped.

[0078] The reaction mixture is washed with water to remove the catalyst; then 0.1% by weight of activated clay is added to the washed product, stirred at 80° C. for 1 hour, and filtered to obtain a decolorized product; the decolorized product is subjected to reduced pressure distillation at 120° C. and -50 kPa to remove the solvent and unreacted raw materials to obtain a long-chain alkyl naphthalene product.

[0079] The average pore size of MOFs catalyst D in this example is 0.8 nm, and the specific surface area is 1254 m 2 / g.

[0080] The long-chain alkyl naphthalene product of this embodiment was analyzed by GC-MS, and the conversion rate of α-methyl naphthalene was shown in Table 1. The kinematic viscosity at 100°C, kinematic viscosity at 40°C, viscosity index, pour point and flash point of the long-chain alkyl naphthalene product of this embodiment are shown in Table 1.

[0081] Example 5

[0082] This embodiment provides a method for preparing alkylnaphthalene using a metal organic framework as a catalyst, which comprises the following steps:

[0083] (1) Preparation of MOFs catalyst E

[0084] 5.15 g Zr(NO3)4·5H2O (0.012 mol) and 0.66 g terephthalic acid (0.004 mol) were dissolved in 40 mL N,N-dimethylformamide, placed in a sealed flask, and the raw materials were completely dissolved by ultrasound to obtain a mixed solution; the mixed solution was transferred into a 50 mL reactor, and the reactor was placed in an electric heated blast drying oven, and the reaction was carried out at 100°C for 48 hours to obtain a reaction product; the reaction product was allowed to cool naturally at room temperature, and after solid-liquid separation, the product was repeatedly washed 3-4 times with N,N-dimethylformamide, and then placed in a drying oven at 80°C and dried for 12 hours to obtain a white solid powder, which is MOFs catalyst E;

[0085] (2) Alkylation of naphthalene using MOFs catalyst E

[0086] 76.90 g of naphthalene and 6.63 g of MOFs catalyst E were added to a three-necked flask equipped with a stirrer and a reflux condenser, and then 110 mL of n-decane was added. The three-necked flask was placed in an oil bath for heating and the stirrer was turned on. Then, a total of 33.66 g of dodecene was added in small amounts and multiple times. After the temperature of the reaction system reached 130° C., the reaction was stirred at a constant temperature for 1 h. When the reaction was completed, the heating was stopped.

[0087] The reaction mixture is washed with water to remove the catalyst; then 0.1% by weight of activated clay is added to the washed product, stirred at 80° C. for 1 hour, and filtered to obtain a decolorized product; the decolorized product is subjected to reduced pressure distillation at 200° C. and 0 kPa to remove the solvent and unreacted raw materials to obtain a long-chain alkyl naphthalene product.

[0088] The average pore size of the MOFs catalyst E in this example is 1.5 nm, and the specific surface area is 1958 m 2 / g.

[0089] The long-chain alkyl naphthalene product of this embodiment was analyzed by GC-MS, and the conversion rate of naphthalene was shown in Table 1. The kinematic viscosity at 100°C, kinematic viscosity at 40°C, viscosity index, pour point and flash point of the long-chain alkyl naphthalene product of this embodiment are shown in Table 1.

[0090] Example 6

[0091] This embodiment provides a method for preparing alkylnaphthalene using a metal organic framework as a catalyst, which comprises the following steps:

[0092] (1) Preparation of MOFs catalyst F

[0093] 0.80 g Cr(NO3)3·9H2O (0.002 mol), 0.86 g Zr(NO3)4·5H2O (0.002 mol) and 0.66 g terephthalic acid (0.004 mol) were dissolved in 40 mL N,N-dimethylformamide, placed in a sealed flask, and the raw materials were completely dissolved by ultrasound to obtain a mixed solution; the mixed solution was transferred into a 50 mL reactor, and the reactor was placed in an electric heated blast drying oven, and the reaction was carried out at 110°C for 60 hours to obtain a reaction product; the reaction product was allowed to cool naturally at room temperature, and after solid-liquid separation, the product was repeatedly washed 3-4 times with N,N-dimethylformamide, and then placed in a drying oven at 80°C for 12 hours to obtain a white solid powder, which is MOFs catalyst F;

[0094] (2) Alkylation of naphthalene and methylnaphthalene using MOFs catalyst F

[0095] 102.54 g of a mixture of naphthalene and α-methylnaphthalene (the mass ratio of naphthalene to α-methylnaphthalene is 1:1) and 1.36 g of MOFs catalyst F are added to a three-necked flask equipped with a stirrer and a reflux condenser, and then 136 mL of n-decane is added. The three-necked flask is placed in an oil bath for heating and the stirrer is turned on. Then, a total of 33.66 g of dodecene is added in small amounts and multiple times. After the temperature of the reaction system reaches 90° C., the reaction is stirred at a constant temperature for 10 hours. When the reaction is completed, the heating is stopped;

[0096] The reaction mixture is washed with water to remove the catalyst; then 0.1% by weight of activated clay is added to the washed product, stirred at 80° C. for 1 hour, and filtered to obtain a decolorized product; the decolorized product is subjected to reduced pressure distillation at 70° C. and -99 kPa to remove the solvent and unreacted raw materials to obtain a long-chain alkyl naphthalene product.

[0097] The average pore size of the MOFs catalyst F in this example is 1.4 nm, and the specific surface area is 1867 m 2 / g.

[0098] The long-chain alkyl naphthalene product of this embodiment was analyzed by GC-MS, and the conversion rates of naphthalene and α-methyl naphthalene were shown in Table 1. The kinematic viscosity at 100°C, kinematic viscosity at 40°C, viscosity index, pour point and flash point of the long-chain alkyl naphthalene product of this embodiment are shown in Table 1.

[0099] Example 7

[0100] This embodiment provides a method for preparing alkylnaphthalene using a metal organic framework as a catalyst, which comprises the following steps:

[0101] (1) Preparation of MOFs catalyst G

[0102] 2.40g Cr(NO3)3·9H2O (0.006mol), 2.25g Al(NO3)3·9H2O (0.006mol) and 0.66g terephthalic acid (0.004mol) were dissolved in 40mL N,N-dimethylformamide, placed in a sealed flask, and the raw materials were completely dissolved by ultrasound to obtain a mixed solution; the mixed solution was transferred into a 50mL reactor, and the reactor was placed in an electric heated blast drying oven, and the reaction was carried out at 140°C for 40h to obtain a reaction product; the reaction product was allowed to cool naturally at room temperature, and after solid-liquid separation, the product was repeatedly washed 3-4 times with N,N-dimethylformamide, and then placed in a drying oven at 80°C and dried for 12h to obtain a white solid powder, which is MOFs catalyst G;

[0103] (2) Alkylation of naphthalene using MOFs catalyst G

[0104] 128.17 g of naphthalene and 3.24 g of MOFs catalyst G were added to a three-necked flask equipped with a stirrer and a reflux condenser, and then 161 mL of n-decane was added. The three-necked flask was placed in an oil bath for heating and the stirrer was turned on. Then, a total of 33.66 g of dodecene was added in small amounts and multiple times. After the temperature of the reaction system reached 140° C., the reaction was stirred at a constant temperature for 0.5 h. When the reaction was completed, the heating was stopped.

[0105] The reaction mixture is washed with water to remove the catalyst; then 0.1% by weight of activated clay is added to the washed product, stirred at 80° C. for 1 hour, and filtered to obtain a decolorized product; the decolorized product is subjected to reduced pressure distillation at 160° C. and -99 kPa to remove the solvent and unreacted raw materials to obtain a long-chain alkyl naphthalene product.

[0106] The average pore size of the MOFs catalyst G in this example is 1.2 nm, and the specific surface area is 1652 m 2 / g.

[0107] The long-chain alkyl naphthalene product of this embodiment was analyzed by GC-MS, and the conversion rate of naphthalene was shown in Table 1. The kinematic viscosity at 100°C, kinematic viscosity at 40°C, viscosity index, pour point and flash point of the long-chain alkyl naphthalene product of this embodiment are shown in Table 1.

[0108] Example 8

[0109] This embodiment provides a method for preparing alkylnaphthalene using a metal organic framework as a catalyst, which comprises the following steps:

[0110] (1) Preparation of MOFs catalyst H

[0111] 1.72g Zr(NO3)4·5H2O (0.004mol), 1.50g Al(NO3)3·9H2O (0.004mol) and 0.66g terephthalic acid (0.004mol) were dissolved in 40mL N,N-dimethylformamide, placed in a sealed flask, and the raw materials were completely dissolved by ultrasound to obtain a mixed solution; the mixed solution was transferred into a 50mL reactor, and the reactor was placed in an electric heated blast drying oven, and the reaction was carried out at 90°C for 15h to obtain a reaction product; the reaction product was allowed to cool naturally at room temperature, and after solid-liquid separation, the product was repeatedly washed 3-4 times with N,N-dimethylformamide, and then placed in a drying oven at 80°C and dried for 12h to obtain a white solid powder, which is MOFs catalyst H;

[0112] (2) Alkylation of naphthalene using MOFs catalyst H

[0113] 25.63 g of naphthalene and 0.53 g of MOFs catalyst H were added to a three-necked flask equipped with a stirrer and a reflux condenser, and then 53 mL of n-decane was added. The three-necked flask was placed in an oil bath for heating and the stirrer was turned on. Then, a total of 28.05 g of 1-decene was added in small amounts and multiple times. After the temperature of the reaction system reached 100° C., the reaction was stirred at a constant temperature for 2 h. When the reaction was completed, the heating was stopped.

[0114] The reaction mixture is washed with water to remove the catalyst; then 0.1% by weight of activated clay is added to the washed product, stirred at 80° C. for 1 hour, and filtered to obtain a decolorized product; the decolorized product is subjected to reduced pressure distillation at 160° C. and -99 kPa to remove the solvent and unreacted raw materials to obtain a long-chain alkyl naphthalene product.

[0115] The average pore size of the MOFs catalyst H in this example is 0.7 nm, and the specific surface area is 1152 m 2 / g.

[0116] The long-chain alkyl naphthalene product of this embodiment was analyzed by GC-MS, and the conversion rate of naphthalene was shown in Table 1. The kinematic viscosity at 100°C, kinematic viscosity at 40°C, viscosity index, pour point and flash point of the long-chain alkyl naphthalene product of this embodiment are shown in Table 1.

[0117] Example 9

[0118] This embodiment provides a method for preparing alkylnaphthalene using a metal organic framework as a catalyst, which comprises the following steps:

[0119] (1) Preparation of MOFs Catalyst I

[0120] 1.60 g Cr(NO3)3·9H2O (0.004 mol), 1.72 g Zr(NO3)4·5H2O (0.004 mol), 1.50 g Al(NO3)3·9H2O (0.004 mol) and 0.66 g terephthalic acid (0.004 mol) were dissolved in 40 mL N,N-dimethylformamide, placed in a sealed flask, and the raw materials were completely dissolved by ultrasound to obtain a mixed solution; the mixed solution was transferred into a 50 mL reactor, and the reactor was placed in an electric heated blast drying oven, and the reaction was carried out at 140° C. for 48 h to obtain a reaction product; the reaction product was allowed to cool naturally at room temperature, and after solid-liquid separation, the product was repeatedly washed 3-4 times with N,N-dimethylformamide, and then placed in a drying oven at 80° C. for 12 h to obtain a white solid powder, which is MOFs catalyst I;

[0121] (2) Alkylation of naphthalene using MOFs catalyst I

[0122] 51.26 g of naphthalene and 3.97 g of MOFs catalyst I were added to a three-necked flask equipped with a stirrer and a reflux condenser, and then 79 mL of n-decane was added. The three-necked flask was placed in an oil bath for heating and the stirrer was turned on. Then, a total of 28.05 g of 1-decene was added in small amounts and multiple times. After the temperature of the reaction system reached 120° C., the reaction was stirred at a constant temperature for 1 h. When the reaction was completed, the heating was stopped.

[0123] The reaction mixture is washed with water to remove the catalyst; then 0.1% by weight of activated clay is added to the washed product, stirred at 80° C. for 1 hour, and filtered to obtain a decolorized product; the decolorized product is subjected to reduced pressure distillation at 160° C. and -99 kPa to remove the solvent and unreacted raw materials to obtain a long-chain alkyl naphthalene product.

[0124] The average pore size of the MOFs catalyst I in this example is 1 nm, and the specific surface area is 1488 m 2 / g.

[0125] The long-chain alkyl naphthalene product of this embodiment was analyzed by GC-MS, and the conversion rate of naphthalene was shown in Table 1. The kinematic viscosity at 100°C, kinematic viscosity at 40°C, viscosity index, pour point and flash point of the long-chain alkyl naphthalene product of this embodiment are shown in Table 1.

[0126] Comparative Example 1

[0127] This comparative example provides a method for preparing alkylnaphthalene using an AlCl3 solid acid catalyst, which comprises the following steps:

[0128] 25.63 g of naphthalene and 0.59 g of AlCl3 were added to a three-necked flask equipped with a stirrer and a reflux condenser, and 60 mL of n-decane was added. The three-necked flask was placed in an oil bath for heating and the stirrer was turned on. Then, a total of 33.66 g of dodecene was added in small amounts and multiple times. After the temperature of the reaction system reached 80°C, the reaction was stirred at a constant temperature for 2 h. The reaction was terminated and the heating was stopped.

[0129] The reaction mixture is washed with water to remove the catalyst; then 0.1% by weight of activated clay is added to the washed product, stirred at 80° C. for 1 hour, and filtered to obtain a decolorized product; the decolorized product is subjected to reduced pressure distillation at 160° C. and -99 kPa to remove the solvent and unreacted raw materials to obtain a long-chain alkyl naphthalene product.

[0130] The long-chain alkyl naphthalene product of this comparative example was analyzed by GC-MS, and the conversion rate of naphthalene was shown in Table 1. The kinematic viscosity at 100°C, kinematic viscosity at 40°C, viscosity index, pour point and flash point of the long-chain alkyl naphthalene product of this comparative example are shown in Table 1.

[0131] Table 1

[0132]

[0133] In summary, the present invention synthesizes MOFs material by hydrothermal method, and it has higher specific surface area and larger pore size. In the preparation process of alkylnaphthalene, the MOFs catalyst of the present invention has the advantages of high catalytic activity, long service life, no pollution, and not easy to corrode equipment, the catalyst life can reach more than 100h, and the conversion rate of naphthalene and / or methylnaphthalene is higher than 98%. At the same time, the alkylnaphthalene product prepared by the present invention has excellent physical and chemical properties, such as viscosity, flash point, pour point, etc., meets the requirements of the art for lubricating oil base oil, and can be directly used as Class V lubricating oil base oil.

Claims

1. A method for preparing alkylnaphthalene using a metal organic framework as a catalyst, comprising the following steps: In the presence of a metal organic framework catalyst, α-olefin and naphthalene and / or methylnaphthalene are subjected to an alkylation reaction to obtain the alkylnaphthalene; The metal organic framework catalyst is prepared by at least the following steps: mixing an inorganic metal salt and an organic ligand in a first solvent to obtain a mixed solution, wherein the inorganic metal salt includes one or a combination of chromium salts, zirconium salts and aluminum salts; reacting the mixed solution for a first time under a first temperature condition to obtain a reaction product; and subjecting the reaction product to solid-liquid separation, washing and drying to obtain the metal organic framework catalyst.

2. The method according to claim 1, wherein: The alkylation reaction is carried out in the presence of a solvent, and the solvent includes one or a combination of several C6-C14 normal alkanes.

3. The method according to claim 1, wherein: The α-olefin includes one or a combination of C8-C20 long-chain α-olefins.

4. The method according to claim 1, wherein: The molar ratio of naphthalene and / or methylnaphthalene:α-olefin is (0.5-5):

1.

5. The method according to claim 1, wherein: The mass ratio of the metal organic framework catalyst: alpha-olefin and naphthalene and / or methylnaphthalene is (0.01-0.1):

1.

6. The method according to claim 1, wherein: The alkylation reaction is carried out at a temperature of 80-150° C., at a pressure of normal pressure, and for a time of 0.5-24 h.

7. The method according to claim 1, wherein: The method further comprises the following steps: after the alkylation reaction is completed, washing the reaction mixture to remove the catalyst, then decolorizing it, and then distilling it under reduced pressure to obtain the alkyl naphthalene.

8. The method according to claim 1, wherein: In the step of preparing the metal organic framework catalyst, the chromium salt includes one or a combination of chromium nitrate, chromium sulfate and chromium chloride.

9. The method according to claim 1, wherein: In the step of preparing the metal organic framework catalyst, the zirconium salt includes one or a combination of zirconium nitrate, zirconium sulfate and zirconium chloride.

10. The method according to claim 1, wherein: In the step of preparing the metal organic framework catalyst, the aluminum salt includes one or a combination of aluminum nitrate, aluminum sulfate and aluminum chloride.

11. The method according to claim 1, wherein: In the step of preparing the metal organic framework catalyst, the organic ligand includes terephthalic acid.

12. The method according to claim 1, wherein: In the step of preparing the metal organic framework catalyst, the molar ratio of the organic ligand to the metal in the inorganic metal salt is 1:(0.5-4).

13. The method according to claim 1, wherein: In the step of preparing the metal organic framework catalyst, the first solvent includes N,N-dimethylformamide.

14. The method according to claim 1, wherein: In the step of preparing the metal organic framework catalyst, the first temperature is 80-150° C., and the first time is 12-72 hours.

15. The method according to claim 1, wherein: The specific surface area of ​​the metal organic framework catalyst is 1000-2000m 2 / gThe average pore size is 0.5-1.5nm.

16. Use of the alkyl naphthalene prepared by the method for preparing alkyl naphthalene using a metal organic framework as a catalyst according to any one of claims 1 to 15 as a Group V lubricant base oil.

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