Iron-magnesium modified ZSM-5 molecular sieve as well as preparation method and application thereof

Abstract

The invention relates to an iron-magnesium modified ZSM-5 molecular sieve as well as a preparation method and application thereof, and belongs to the technical field of preparation of molecular sieve catalysts. The preparation method of the iron-magnesium modified ZSM-5 molecular sieve provided by the invention comprises the following steps: (1) mixing and modifying a mixed solution of organic alkali and inorganic alkali and a ZSM-5 molecular sieve, washing, drying and roasting to obtain an alkali modified ZSM-5 molecular sieve; and (2) mixing and dissolving iron salt, magnesium salt and the alkali modified ZSM-5 molecular sieve obtained in the step (1) in a solvent, evaporating the solvent to dryness, drying and roasting to obtain the iron-magnesium modified ZSM-5 molecular sieve. According to the method, iron and magnesium are adopted to modify the alkali-modified ZSM-5 molecular sieve at the same time, the content of L acid in the ZSM-5 molecular sieve can be increased through introduction of iron and magnesium, side reactions are inhibited on the premise that the skeleton structure of the molecular sieve is not damaged, and excellent stability and catalytic performance are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of molecular sieve catalysts, and particularly relates to an iron-magnesium modified ZSM-5 molecular sieve, a preparation method thereof, and an application thereof. Background Art

[0002] Alkylnaphthalenes have the advantages of high oxidation stability, high flash point, good thermal stability, high safety, etc. Among them, long-chain alkylnaphthalenes have more excellent additive solubility, good anti-emulsification performance, and good compatibility, etc., and play an important role in synthetic lubricating oils and are widely used in hydraulic oils, gear oils, heat transfer oils, transformer oils, refrigeration oils, compressor oils, liquid crystals and other fields.

[0003] The preparation of long-chain alkylnaphthalenes usually uses traditional liquid inorganic acids such as trifluoromethanesulfonic acid, concentrated sulfuric acid, and hydrofluoric acid or Lewis acids such as aluminum trichloride and iron trichloride as catalysts. The problem of serious corrosion of equipment leads to difficult separation of the product and the catalyst or high separation cost, high environmental pressure, and does not meet the requirements of green chemistry.

[0004] Molecular sieves are widely used as catalysts in hydrocarbon processing due to their specific pore structure and pore size. Patent CN105289747A provides a supported ultra-stable Y molecular sieve catalyst, a preparation method thereof, and a method for catalyzing the synthesis of long-chain alkylnaphthalenes. The supported Y molecular sieve can continuously and stably operate the alkylation reaction in a fixed bed for a long time. The prepared long-chain alkylnaphthalene has low chromaticity and small acid value and has certain application prospects. However, this method requires the addition of n-heptane as a solvent, and the reaction requires pressurization. The subsequent removal of n-heptane has high energy consumption and high industrialization cost.

[0005] Therefore, it is of great significance to develop molecular sieves with high activity and good stability for catalyzing the preparation of long-chain alkylnaphthalenes. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art and provide an iron-magnesium modified ZSM-5 molecular sieve, a preparation method thereof, and an application thereof.

[0007] The present invention is realized by the following technical solutions:

[0008] The present invention provides a preparation method of an iron-magnesium modified ZSM-5 molecular sieve, comprising the following steps:

[0009] (1) Mix and modify a mixed solution of an organic base and an inorganic base with a ZSM-5 molecular sieve, wash, dry, and calcine to obtain an alkali-modified ZSM-5 molecular sieve;

[0010] (2) Mix the iron salt, magnesium salt and the alkali-modified ZSM-5 molecular sieve obtained in step (1) in a solvent, evaporate the solvent to dryness, dry, and calcine to obtain the iron-magnesium modified ZSM-5 molecular sieve.

[0011] In the present invention, the ZSM-5 molecular sieve is modified by using a mixed alkali solution including an inorganic alkali and an organic quaternary ammonium alkali. Among them, the desilication rate of the inorganic alkali is fast, but it will cause a decrease in thermal stability; the desilication rate of the quaternary ammonium alkali is relatively slow, the desilication rate is easy to control, and no further ammonium exchange is required subsequently. The two are used in combination to perform alkali treatment on the ZSM-5 molecular sieve, which can moderately modify the pore structure and acidity of the ZSM-5 molecular sieve while maintaining the molecular sieve framework structure, thereby being beneficial to improving the catalytic effect of the molecular sieve. Further, in the present invention, the alkali-modified ZSM-5 molecular sieve is impregnated and calcined in a mixed solution of iron and magnesium, so that iron and magnesium simultaneously modify the ZSM-5 molecular sieve. The introduction of iron and magnesium can increase the content of L acid in the ZSM-5 molecular sieve, and on the premise of not destroying the molecular sieve framework structure, inhibit the occurrence of side reactions. The modified ZSM-5 molecular sieve is used in the alkylation reaction of catalytic long-chain olefins and naphthalene to prepare long-chain alkylnaphthalenes, and has excellent stability and catalytic performance.

[0012] As a preferred embodiment of the preparation method of the iron-magnesium modified ZSM-5 molecular sieve of the present invention, the organic alkali includes tetrapropylammonium hydroxide, and the inorganic alkali includes sodium hydroxide; the concentration of OH - in the mixed solution is 0.1 mol / L - 1.2 mol / L.

[0013] Preferably, the concentration of OH - in the mixed solution is 0.2 mol / L - 0.8 mol / L.

[0014] As a preferred embodiment of the preparation method of the iron-magnesium modified ZSM-5 molecular sieve of the present invention, in step (1), the solid-liquid ratio of the ZSM-5 molecular sieve to the mixed solution of the organic alkali and the inorganic alkali is 1 g:(5 - 20) mL.

[0015] Preferably, in the mixed solution of the organic alkali and the inorganic alkali, the molar ratio of the organic alkali to the inorganic alkali is 0.1 - 2; more preferably, the molar ratio of the organic alkali to the inorganic alkali is 0.2 - 1.

[0016] As a preferred embodiment of the preparation method of the iron-magnesium modified ZSM-5 molecular sieve of the present invention, in step (1), the temperature of the mixed modification is 50°C - 100°C, and the time is 10 min - 240 min; preferably, the temperature of the mixed modification is 60°C - 80°C, and the time is 30 min - 120 min.

[0017] As a preferred embodiment of the preparation method of the iron-magnesium modified ZSM-5 molecular sieve of the present invention, in the step (1), the drying temperature is 60°C - 140°C; preferably, the drying temperature is 80°C - 120°C.

[0018] As a preferred embodiment of the preparation method of the iron-magnesium modified ZSM-5 molecular sieve of the present invention, in the step (1), the calcination temperature is 400°C - 700°C, and the time is 3h - 10h; preferably, the calcination temperature is 500°C - 650°C, and the time is 4h - 8h.

[0019] Preferably, in the step (1), the washing is carried out by washing with water until neutral.

[0020] Preferably, in the step (2), the solvent includes one or more of water, ethanol, methanol, isopropanol, benzene, and toluene.

[0021] As a preferred embodiment of the preparation method of the iron-magnesium modified ZSM-5 molecular sieve of the present invention, the iron salt includes at least one of iron nitrate, iron sulfate, and iron chloride; the magnesium salt includes at least one of magnesium nitrate, magnesium sulfate, and magnesium chloride.

[0022] As a preferred embodiment of the preparation method of the iron-magnesium modified ZSM-5 molecular sieve of the present invention, in the iron-magnesium modified ZSM-5 molecular sieve, the iron accounts for 0.2% - 8% of the mass of the iron-magnesium modified ZSM-5 molecular sieve, and the magnesium accounts for 0.2% - 8% of the mass of the iron-magnesium modified ZSM-5 molecular sieve.

[0023] In the present invention, the proportion of iron or magnesium in the molecular sieve refers to the mass proportion of iron element or magnesium element in the molecular sieve.

[0024] Preferably, in the iron-magnesium modified ZSM-5 molecular sieve, the iron accounts for 0.5% - 5% of the mass of the iron-magnesium modified ZSM-5 molecular sieve, and the magnesium accounts for 0.5% - 5% of the mass of the iron-magnesium modified ZSM-5 molecular sieve.

[0025] As a preferred embodiment of the preparation method of the iron-magnesium modified ZSM-5 molecular sieve of the present invention, in the iron-magnesium modified ZSM-5 molecular sieve, the mass ratio of magnesium to iron is (0.5 - 3):1.

[0026] Preferably, in the iron-magnesium modified ZSM-5 molecular sieve, the mass ratio of magnesium to iron is (1 - 3):1.

[0027] As a preferred embodiment of the preparation method of the iron-magnesium modified ZSM-5 molecular sieve of the present invention, the silica-alumina ratio of the ZSM-5 molecular sieve is 5 - 500.

[0028] Preferably, the silica-alumina ratio of the ZSM-5 molecular sieve is 5 to 200.

[0029] As a preferred embodiment of the preparation method of the iron-magnesium modified ZSM-5 molecular sieve of the present invention, the drying temperature is 60°C to 140°C, and the time is 8h to 24h.

[0030] Preferably, the drying temperature is 80°C to 120°C, and the time is 12h to 18h.

[0031] As a preferred embodiment of the preparation method of the iron-magnesium modified ZSM-5 molecular sieve of the present invention, the calcination temperature is 400°C to 700°C, and the time is 3h to 10h.

[0032] Preferably, the calcination temperature is 500°C to 650°C, and the time is 4h to 8h.

[0033] Another object of the present invention is to provide an iron-magnesium modified ZSM-5 molecular sieve prepared by the preparation method of the iron-magnesium modified ZSM-5 molecular sieve.

[0034] In the iron-magnesium modified ZSM-5 molecular sieve prepared by the present invention, iron or magnesium exists in the form of oxides. Iron and magnesium simultaneously modify the ZSM-5 molecular sieve, and the obtained modified molecular sieve can inhibit carbon deposition deactivation during the reaction. As a catalyst, it is pollution-free, has a long service life, and can be reused.

[0035] Another object of the present invention is to provide the application of the iron-magnesium modified ZSM-5 molecular sieve in the catalytic preparation of long-chain alkylnaphthalenes.

[0036] The iron-magnesium modified ZSM-5 molecular sieve of the present invention has high catalytic activity when applied to the catalytic preparation of long-chain alkylnaphthalenes, and has extremely high reaction conversion rate and selectivity.

[0037] Another object of the present invention is to provide a method for preparing long-chain alkylnaphthalenes, comprising the following steps:

[0038] (1) In the presence of the iron-magnesium modified ZSM-5 molecular sieve, naphthalene and long-chain olefins are subjected to an alkylation reaction to obtain a crude product of alkylnaphthalene;

[0039] (2) The crude alkylnaphthalene product obtained in step (1) is filtered to remove the solid catalyst, and then the unreacted long-chain olefins and naphthalene are removed. The obtained solution is heated and decolorized using activated clay, and after decolorization, the activated clay is removed to obtain a first alkylnaphthalene;

[0040] (3) The first alkylnaphthalene obtained in step (2) is subjected to vacuum distillation to obtain a second alkylnaphthalene.

[0041] In the method for preparing long-chain alkylnaphthalene of the present invention, the iron-magnesium modified ZSM-5 molecular sieve used as a catalyst has higher catalytic activity compared to the unmodified ZSM-5 and the single-metal modified ZSM-5 molecular sieves. Moreover, this method does not require the use of organic solvents such as cyclohexane and n-heptane. After the reaction, the unreacted raw materials are removed, and the first high-viscosity component of alkylnaphthalene-based lubricating oil base oil can be directly obtained. The separation process is simple and efficient. The obtained first high-viscosity alkylnaphthalene can be further distilled to obtain the second low-viscosity component of alkylnaphthalene-based lubricating oil base oil.

[0042] Preferably, in the step (1), the long-chain olefin is a straight-chain α-olefin with 8 to 18 carbon atoms.

[0043] Preferably, in the step (1), the molar ratio of the naphthalene to the long-chain olefin is (1 to 3.5):1.

[0044] Preferably, in the step (1), the addition amount of the iron-magnesium modified ZSM-5 molecular sieve is 0.2% to 20% of the mass of the naphthalene; more preferably, in the step (1), the addition amount of the iron-magnesium modified ZSM-5 molecular sieve is 1% to 15% of the mass of the naphthalene.

[0045] Preferably, in the step (1), the temperature of the alkylation reaction is 90°C to 210°C, and the time is 0.5 h to 7 h; more preferably, in the step (1), the temperature of the alkylation reaction is 100°C to 190°C, and the time is 1 h to 5 h.

[0046] Preferably, in the step (2), the addition amount of the activated clay is 1% to 20% of the mass of the solution; more preferably, in the step (2), the addition amount of the activated clay is 3% to 15% of the mass of the solution.

[0047] Preferably, in the step (2), the temperature of the heating and decolorization is 70°C to 150°C, and the time is 30 min to 300 min; more preferably, in the step (2), the temperature of the heating and decolorization is 80°C to 130°C, and the time is 60 min to 240 min.

[0048] Preferably, in the step (3), the temperature of the vacuum distillation is 180°C to 230°C.

[0049] The present invention has the following beneficial effects: The present invention impregnates the ZSM-5 molecular sieve in a composite solution of iron and magnesium, enabling iron and magnesium to modify the molecular sieve simultaneously. The obtained modified molecular sieve has excellent catalytic activity, and can significantly improve the conversion rate and selectivity of the reaction compared to the single-metal modified and unmodified molecular sieves. The preparation method of the present invention is simple, the obtained modified molecular sieve has high catalytic activity, and has broad industrial application prospects. Detailed implementation manners

[0050] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0051] Unless otherwise specified, the test methods used in the examples are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels.

[0052] The analysis methods, conversion rates and selectivities of the following examples and comparative examples of the present invention are calculated as follows:

[0053] The conversion rate and selectivity of alkylnaphthalene were measured by gas chromatography. The instrument model is A90 from Zhejiang Fuli Co., Ltd., with an FID detector, nitrogen as the carrier gas, an injection volume of 2 μL, a split ratio of 50:1, and the temperature of the front injection port is 280 °C. Different heating programs are adopted according to different raw materials.

[0054] The kinematic viscosity of the long-chain alkylnaphthalene lubricating oil was measured according to the standards of GB / T 265-1988 and GB / T 3535-2006.

[0055] Unless otherwise specified, the ratio of ions in each example and comparative example is the molar ratio.

[0056] Example 1

[0057] The preparation method of the iron-magnesium modified ZSM-5 molecular sieve in this example includes the following steps:

[0058] (1) According to the molar ratio of tetrapropylammonium hydroxide to sodium hydroxide being 0.4, a mixed solution with an OH - content of 0.45 mol / L was prepared. 10 g of ZSM-5 molecular sieve with a silica-alumina ratio of 30 was taken and added to the above mixed solution according to a solid-liquid ratio of 1 g:10 mL. Stir at 80 °C for 1.5 h, quench in ice water, filter, wash with deionized water until neutral, dry the filter cake at 80 °C for 16 h, and then calcine in a muffle furnace at 600 °C for 5 h to obtain the alkali-modified ZSM-5 molecular sieve;

[0059] (2) 1.62 g of iron nitrate and 1.81 g of magnesium chloride were dissolved in 40 mL of water, and the mixed solution was added to 10 g of the alkali-modified ZSM-5 molecular sieve obtained in step (1). The solvent was evaporated by heating in a water bath at 80 °C under stirring conditions, dried in an oven at 120 °C for 12 h, and then calcined in a muffle furnace at 550 °C for 4 h to obtain the iron-magnesium modified ZSM-5 molecular sieve in this example; wherein, iron accounts for 2% of the mass of the iron-magnesium modified ZSM-5 molecular sieve, and magnesium accounts for 4% of the mass of the iron-magnesium modified ZSM-5 molecular sieve.

[0060] The obtained iron-magnesium modified ZSM-5 molecular sieve is used to prepare long-chain alkylnaphthalenes. The preparation method of the long-chain alkylnaphthalenes comprises the following steps:

[0061] (1) Naphthalene and the long-chain olefin 1-octene are added to a three-necked flask according to a molar ratio of 1.5:1, stirred and heated to 110 °C, and 5% by mass of the above-mentioned iron-magnesium modified ZSM-5 molecular sieve based on the mass of naphthalene is added, and the reaction is carried out for 2 h to obtain a crude product of alkylnaphthalene; among them, the conversion rate of 1-octene is 99%, and the selectivity is 99%.

[0062] (2) After cooling the crude product of alkylnaphthalene obtained in step (1) to room temperature, the solid is filtered off, the unreacted long-chain olefin and naphthalene are removed by vacuum distillation, 6% by mass of activated clay is added to the obtained solution, and the mixture is stirred at 100 °C for 60 min. After removing the activated clay, a first high-viscosity alkylnaphthalene-based lubricating oil base oil is obtained;

[0063] (3) The first high-viscosity alkylnaphthalene lubricating oil base oil obtained in step (2) is subjected to vacuum distillation at 180 °C, and the obtained distillate is a second low-viscosity component alkylnaphthalene lubricating oil base oil; the kinematic viscosities of the two alkylnaphthalenes at 100 °C are 2.65 mm 2 / s and 2.20 mm 2 / s, and the pour points are -39 °C and -41 °C respectively.

[0064] Example 2

[0065] The preparation method of the iron-magnesium modified ZSM-5 molecular sieve in this example comprises the following steps:

[0066] (1) A mixed solution with an OH - content of 0.45 mol / L is prepared according to a molar ratio of tetrapropylammonium hydroxide to sodium hydroxide of 0.4. 10 g of ZSM-5 molecular sieve with a silica-alumina ratio of 100 is taken and added to the above-mentioned mixed solution according to a solid-liquid ratio of 1 g:10 mL. The mixture is stirred at 80 °C for 1.5 h, quenched in ice water, filtered, washed with deionized water until neutral, the filter cake is dried at 80 °C for 16 h, and then calcined in a muffle furnace at 600 °C for 5 h to obtain an alkali-modified ZSM-5 molecular sieve;

[0067] (2) 0.32 g of ferric chloride and 2.04 g of magnesium nitrate are dissolved in 40 mL of methanol, and the mixed solution is added to 10 g of the alkali-modified ZSM-5 molecular sieve obtained in step (1). The solvent is evaporated by heating in a water bath at 90 °C under stirring conditions, dried in an oven at 110 °C for 14 h, and then calcined in a muffle furnace at 500 °C for 6 h to obtain the iron-magnesium modified ZSM-5 molecular sieve of this example; among them, iron accounts for 1% of the mass of the iron-magnesium modified ZSM-5 molecular sieve, and magnesium accounts for 3% of the mass of the iron-magnesium modified ZSM-5 molecular sieve.

[0068] The obtained iron-magnesium modified ZSM-5 molecular sieve is used for preparing long-chain alkylnaphthalene. The preparation method of the long-chain alkylnaphthalene comprises the following steps:

[0069] (1) Naphthalene and long-chain olefin 1-decene are added into a three-necked flask according to a molar ratio of 2:1, stirred and heated to 130°C, and 8% of the above-mentioned iron-magnesium modified ZSM-5 molecular sieve based on the mass of naphthalene is added, and the reaction is carried out for 2 h to obtain a crude product of alkylnaphthalene; wherein, the conversion rate of 1-decene is 99%, and the selectivity is 99%.

[0070] (2) After cooling the crude product of alkylnaphthalene obtained in step (1) to room temperature, the solid is filtered off, the unreacted long-chain olefin and naphthalene are removed by vacuum distillation, 8% of activated clay based on the mass of the obtained solution is added, and the mixture is stirred at 90°C for 120 min. After removing the activated clay, the first high-viscosity alkylnaphthalene-type lubricating oil base oil is obtained;

[0071] (3) The first high-viscosity alkylnaphthalene lubricating oil base oil obtained in step (2) is subjected to vacuum distillation at 185°C, and the obtained distillate is the second low-viscosity component of alkylnaphthalene lubricating oil base oil; the kinematic viscosities of two kinds of decylnaphthalene at 100°C are 3.30 mm 2 / s and 2.59 mm 2 / s respectively, and the pour points are -40°C and -43°C respectively.

[0072] Example 3

[0073] The preparation method of the iron-magnesium modified ZSM-5 molecular sieve in this example comprises the following steps:

[0074] (1) According to a molar ratio of tetrapropylammonium hydroxide to sodium hydroxide of 0.4, a mixed solution with an OH - content of 0.45 mol / L is prepared. 10 g of ZSM-5 molecular sieve with a silica-alumina ratio of 80 is taken and added to the above-mentioned mixed solution according to a solid-liquid ratio of 1 g:10 mL. The mixture is stirred at 80°C for 1.5 h, quenched in ice water, filtered, washed with deionized water until neutral, and the filter cake is dried at 80°C for 16 h and then calcined in a muffle furnace at 600°C for 5 h to obtain an alkali-modified ZSM-5 molecular sieve;

[0075] (2) 2.36 g of ferric sulfate and 2.04 g of magnesium nitrate are dissolved in ethanol, and the mixed solution is added to 10 g of the alkali-modified ZSM-5 molecular sieve obtained in step (1). The solvent is evaporated by heating in a water bath at 80°C under stirring conditions and dried in an oven at 110°C for 16 h, and then calcined in a muffle furnace at 550°C for 5 h to obtain the iron-magnesium modified ZSM-5 molecular sieve of this example; wherein, iron accounts for 3% of the mass of the iron-magnesium modified ZSM-5 molecular sieve, and magnesium accounts for 3% of the mass of the iron-magnesium modified ZSM-5 molecular sieve.

[0076] The obtained iron-magnesium modified ZSM-5 molecular sieve is used for preparing long-chain alkylnaphthalene. The preparation method of the long-chain alkylnaphthalene comprises the following steps:

[0077] (1) Naphthalene and long-chain olefin 1-dodecene are added into a three-necked flask according to a molar ratio of 2.5:1, stirred and heated to 140 °C, and 6% of the above-mentioned iron-magnesium modified ZSM-5 molecular sieve based on the mass of naphthalene is added, and the reaction is carried out for 3 h to obtain a crude product of alkylnaphthalene; wherein, the conversion rate of 1-dodecene is 99%, and the selectivity is 99%.

[0078] (2) After the crude product of alkylnaphthalene obtained in step (1) is cooled to room temperature, the solid is filtered off, and the unreacted long-chain olefin and naphthalene are removed by vacuum distillation. 6% of activated clay based on the mass of the obtained solution is added, and the mixture is stirred at 110 °C for 80 min. After removing the activated clay, the first high-viscosity alkylnaphthalene type lubricating oil base oil is obtained;

[0079] (3) The first high-viscosity alkylnaphthalene lubricating oil base oil obtained in step (2) is subjected to vacuum distillation at 190 °C, and the obtained distillate is the second low-viscosity component of alkylnaphthalene lubricating oil base oil; the kinematic viscosities of the two dodecylnaphthalenes at 100 °C are 4.31 mm 2 / s and 3.72 mm 2 / s respectively, and the pour points are -38 °C and -41 °C respectively.

[0080] Example 4

[0081] The preparation method of the iron-magnesium modified ZSM-5 molecular sieve in this example comprises the following steps:

[0082] (1) According to a molar ratio of tetrapropylammonium hydroxide to sodium hydroxide of 0.4, a mixed solution with an OH - content of 0.45 mol / L is prepared. 10 g of ZSM-5 molecular sieve with a silica-alumina ratio of 20 is taken and added to the above-mentioned mixed solution according to a solid-liquid ratio of 1 g:10 mL. The mixture is stirred at 80 °C for 1.5 h, quenched in ice water, filtered, washed with deionized water until neutral, and the filter cake is dried at 80 °C for 16 h and then calcined in a muffle furnace at 600 °C for 5 h to obtain an alkali-modified ZSM-5 molecular sieve;

[0083] (2) 1.57 g of ferric sulfate and 1.75 g of magnesium chloride are dissolved in toluene, and the mixed solution is added to 10 g of the alkali-modified ZSM-5 molecular sieve obtained in step (1). The solvent is evaporated to dryness by heating in a water bath at 80 °C under stirring conditions, dried in an oven at 100 °C for 16 h, and then calcined in a muffle furnace at 600 °C for 4 h to obtain the iron-magnesium modified ZSM-5 molecular sieve of this example; wherein, iron accounts for 1% of the mass of the iron-magnesium modified ZSM-5 molecular sieve, and magnesium accounts for 2% of the mass of the iron-magnesium modified ZSM-5 molecular sieve.

[0084] The obtained iron-magnesium modified ZSM-5 molecular sieve is used for preparing long-chain alkylnaphthalene. The preparation method of the long-chain alkylnaphthalene comprises the following steps:

[0085] (1) Naphthalene and long-chain olefin 1-tetradecene are added into a three-necked flask according to a molar ratio of 3:1, stirred and heated to 140 °C, and 8% by mass of the above-mentioned iron-magnesium modified ZSM-5 molecular sieve based on the mass of naphthalene is added, and the reaction is carried out for 3 h to obtain a crude product of alkylnaphthalene; wherein, the conversion rate of 1-tetradecene is 99%, and the selectivity is 99%.

[0086] (2) After the crude product of alkylnaphthalene obtained in step (1) is cooled to room temperature, solids are removed by filtration, unreacted long-chain olefin and naphthalene are removed by vacuum distillation, 8% by mass of activated clay based on the mass of the obtained solution is added, and stirring is carried out at 105 °C for 90 min, and after removing the activated clay, a first high-viscosity alkylnaphthalene type lubricating oil base oil is obtained;

[0087] (3) The first high-viscosity alkylnaphthalene lubricating oil base oil obtained in step (2) is subjected to vacuum distillation at 200 °C, and the obtained distillate is a second low-viscosity component of alkylnaphthalene lubricating oil base oil; the kinematic viscosities of two kinds of tetradecylnaphthalene at 100 °C are 4.52 mm 2 / s and 3.81 mm 2 / s respectively, and the pour points are -40 °C and -43 °C respectively.

[0088] Example 5

[0089] The preparation method of the iron-magnesium modified ZSM-5 molecular sieve in this example comprises the following steps:

[0090] (1) According to a molar ratio of tetrapropylammonium hydroxide to sodium hydroxide of 0.4, a mixed solution with an OH - content of 0.45 mol / L is prepared. 10 g of ZSM-5 molecular sieve with a silica-alumina ratio of 50 is taken and added to the above-mentioned mixed solution according to a solid-liquid ratio of 1 g:10 mL, stirred at 80 °C for 1.5 h, quenched in ice water, filtered, washed with deionized water until neutral, the filter cake is dried at 80 °C for 16 h, and then calcined in a muffle furnace at 600 °C for 5 h to obtain an alkali-modified ZSM-5 molecular sieve;

[0091] (2) 2.43 g of iron nitrate and 2.63 g of magnesium chloride are dissolved in 50 mL of water, and this mixed solution is added to 15 g of the alkali-modified ZSM-5 molecular sieve obtained in step (1). The solvent is evaporated to dryness by heating in a water bath at 80 °C under stirring conditions, dried in an oven at 110 °C for 16 h, and then calcined in a muffle furnace at 550 °C for 5 h to obtain the iron-magnesium modified ZSM-5 molecular sieve of this example; wherein, iron accounts for 2% of the mass of the iron-magnesium modified ZSM-5 molecular sieve, and magnesium accounts for 4% of the mass of the iron-magnesium modified ZSM-5 molecular sieve.

[0092] The obtained iron-magnesium modified ZSM-5 molecular sieve is used for preparing long-chain alkylnaphthalene. The preparation method of the long-chain alkylnaphthalene comprises the following steps:

[0093] (1) Naphthalene and long-chain olefin 1-hexadecene are added into a three-necked flask according to a molar ratio of 2:1, stirred and heated to 160 °C, and 10% of the above-mentioned iron-magnesium modified ZSM-5 molecular sieve based on the mass of naphthalene is added, and the reaction is carried out for 3 h to obtain a crude product of alkylnaphthalene; wherein, the conversion rate of 1-hexadecene is 99%, and the selectivity is 99%.

[0094] (2) After the crude product of alkylnaphthalene obtained in step (1) is cooled to room temperature, the solid is filtered off, the unreacted long-chain olefin and naphthalene are removed by vacuum distillation, 4% of activated clay based on the mass of the obtained solution is added, and the mixture is stirred at 100 °C for 90 min. After removing the activated clay, the first high-viscosity alkylnaphthalene type lubricating oil base oil is obtained;

[0095] (3) The first high-viscosity alkylnaphthalene lubricating oil base oil obtained in step (2) is vacuum distilled at 220 °C, and the obtained distillate is the second low-viscosity component of alkylnaphthalene lubricating oil base oil; the kinematic viscosities of the two hexadecylnaphthalenes at 100 °C are 5.01 mm 2 / s and 4.29 mm 2 / s respectively, and the pour points are -40 °C and -42 °C respectively.

[0096] The iron-magnesium modified ZSM-5 molecular sieve obtained in this example is filtered and recovered after one alkylnaphthalene preparation reaction, and is catalytically used in a cycle for 5 times. The conversion rate and selectivity of each time are statistically analyzed. The conversion rates of the 5 times are 99%, 99%, 98%, 97%, and 97% respectively, and the selectivities are 99%, 98%, 97%, 97%, and 96% respectively, indicating that the iron-magnesium modified ZSM-5 molecular sieve of the present invention can be used in a cycle for multiple times, and the catalytic activity is not significantly reduced.

[0097] Example 6

[0098] The preparation method of the iron-magnesium modified ZSM-5 molecular sieve in this example comprises the following steps:

[0099] (1) A mixed solution with an OH - content of 0.45 mol / L is prepared according to a molar ratio of tetrapropylammonium hydroxide to sodium hydroxide of 0.4. 10 g of ZSM-5 molecular sieve with a silica-alumina ratio of 80 is taken and added to the above-mentioned mixed solution according to a solid-liquid ratio of 1 g:10 mL. The mixture is stirred at 80 °C for 1.5 h, quenched in ice water, filtered, washed with deionized water until neutral, and the filter cake is dried at 80 °C for 16 h and then calcined in a muffle furnace at 600 °C for 5 h to obtain an alkali-modified ZSM-5 molecular sieve;

[0100] (2) Dissolve 1.12 g of iron nitrate and 0.62 g of magnesium chloride in methanol, and add the mixed solution to 15 g of the alkali-modified ZSM-5 molecular sieve obtained in step (1). Heat the solution in a water bath at 80 °C with stirring until the solvent is evaporated to dryness, dry it in an oven at 110 °C for 16 h, and then calcine it in a muffle furnace at 600 °C for 5 h to obtain the iron-magnesium modified ZSM-5 molecular sieve of this example; among them, iron accounts for 1% of the mass of the iron-magnesium modified ZSM-5 molecular sieve, and magnesium accounts for 1% of the mass of the iron-magnesium modified ZSM-5 molecular sieve.

[0101] Use the obtained iron-magnesium modified ZSM-5 molecular sieve to prepare long-chain alkylnaphthalene. The preparation method of the long-chain alkylnaphthalene includes the following steps:

[0102] (1) Add naphthalene and long-chain olefin 1-octadecene to a three-necked flask according to a molar ratio of 1.5:1, stir and heat up to 180 °C, add the above-mentioned iron-magnesium modified ZSM-5 molecular sieve accounting for 12% of the mass of naphthalene, and react for 4 h to obtain a crude product of alkylnaphthalene; among them, the conversion rate of 1-octadecene is 96%, and the selectivity is 96%.

[0103] (2) After cooling the crude product of alkylnaphthalene obtained in step (1) to room temperature, filter to remove the solid, remove the unreacted long-chain olefin and naphthalene by vacuum distillation, add activated clay accounting for 10% of the mass of the obtained solution, stir at 120 °C for 120 min, and remove the activated clay to obtain the first high-viscosity alkylnaphthalene type lubricating oil base oil;

[0104] (3) Vacuum distill the first high-viscosity alkylnaphthalene lubricating oil base oil obtained in step (2) at 225 °C, and the obtained distillate is the second low-viscosity component of alkylnaphthalene lubricating oil base oil; the kinematic viscosities of the two octadecylnaphthalenes at 100 °C are 5.46 mm 2 / s and 4.71 mm 2 / s, and the pour points are -41 °C and -43 °C respectively.

[0105] Example 7

[0106] The preparation method of the iron-magnesium modified ZSM-5 molecular sieve of this example includes the following steps:

[0107] (1) Prepare a mixed solution with an OH - content of 0.8 mol / L according to a molar ratio of tetrapropylammonium hydroxide to sodium hydroxide of 0.2. Take 10 g of ZSM-5 molecular sieve with a silica-alumina ratio of 30, add the above-mentioned mixed solution according to a solid-liquid ratio of 1 g:10 mL, stir at 80 °C for 0.5 h, quench in ice water, filter, wash with deionized water until neutral, dry the filter cake at 80 °C for 16 h, and then calcine it in a muffle furnace at 650 °C for 4 h to obtain the alkali-modified ZSM-5 molecular sieve;

[0108] (2) Dissolve 1.62 g of iron nitrate and 1.81 g of magnesium chloride in 40 mL of water, add the mixture to 10 g of the alkali-modified ZSM-5 molecular sieve obtained in step (1), evaporate the solvent by heating in a water bath at 80 °C under stirring conditions, dry in an oven at 120 °C for 12 h, and then calcine in a muffle furnace at 550 °C for 4 h to obtain the iron-magnesium modified ZSM-5 molecular sieve of this example; among them, iron accounts for 2% of the mass of the iron-magnesium modified ZSM-5 molecular sieve, and magnesium accounts for 4% of the mass of the iron-magnesium modified ZSM-5 molecular sieve.

[0109] Use the obtained iron-magnesium modified ZSM-5 molecular sieve to prepare long-chain alkylnaphthalene. The preparation method of the long-chain alkylnaphthalene is the same as that in Example 1. The conversion rate of 1-octene in this example is 97%, and the selectivity is 96%.

[0110] Example 8

[0111] The preparation method of the iron-magnesium modified ZSM-5 molecular sieve in this example includes the following steps:

[0112] (1) Prepare a mixed solution with an OH content of 0.2 mol / L according to a molar ratio of tetrapropylammonium hydroxide to sodium hydroxide of 1. Take 10 g of ZSM-5 molecular sieve with a silica-alumina ratio of 30, add the above mixed solution according to a solid-liquid ratio of 1 g:10 mL, stir at 60 °C for 2 h, quench in ice water, filter, wash with deionized water until neutral, dry the filter cake at 120 °C for 16 h, and then calcine in a muffle furnace at 500 °C for 8 h to obtain the alkali-modified ZSM-5 molecular sieve; - (1) Prepare a mixed solution with an OH content of 0.2 mol / L according to a molar ratio of tetrapropylammonium hydroxide to sodium hydroxide of 1. Take 10 g of ZSM-5 molecular sieve with a silica-alumina ratio of 30, add the above mixed solution according to a solid-liquid ratio of 1 g:10 mL, stir at 60 °C for 2 h, quench in ice water, filter, wash with deionized water until neutral, dry the filter cake at 120 °C for 16 h, and then calcine in a muffle furnace at 500 °C for 8 h to obtain the alkali-modified ZSM-5 molecular sieve;

[0113] (2) Dissolve 1.62 g of iron nitrate and 1.81 g of magnesium chloride in 40 mL of water, add the mixture to 10 g of the alkali-modified ZSM-5 molecular sieve obtained in step (1), evaporate the solvent by heating in a water bath at 80 °C under stirring conditions, dry in an oven at 120 °C for 12 h, and then calcine in a muffle furnace at 550 °C for 4 h to obtain the iron-magnesium modified ZSM-5 molecular sieve of this example; among them, iron accounts for 2% of the mass of the iron-magnesium modified ZSM-5 molecular sieve, and magnesium accounts for 4% of the mass of the iron-magnesium modified ZSM-5 molecular sieve.

[0114] Use the obtained iron-magnesium modified ZSM-5 molecular sieve to prepare long-chain alkylnaphthalene. The preparation method of the long-chain alkylnaphthalene is the same as that in Example 1. The conversion rate of 1-octene in this example is 96%, and the selectivity is 96%.

[0115] Example 9

[0116] The preparation method of the iron-magnesium modified ZSM-5 molecular sieve in this example includes the following steps:

[0117] (1) Prepare a mixed solution with an OH content of 0.2 mol / L according to a molar ratio of tetrapropylammonium hydroxide to sodium hydroxide of 0.1,- A mixed solution with a content of 0.1 mol / L was taken. 10 g of ZSM-5 zeolite with a silica-alumina ratio of 30 was added to the above mixed solution according to a solid-liquid ratio of 1 g:10 mL. It was stirred at 50 °C for 4 h, quenched in ice water, filtered, washed with deionized water until neutral, and the filter cake was dried at 60 °C for 16 h and then calcined in a muffle furnace at 400 °C for 10 h to obtain alkali-modified ZSM-5 zeolite;

[0118] (2) 1.62 g of iron nitrate and 1.81 g of magnesium chloride were dissolved in 40 mL of water, and the mixed solution was added to 10 g of the alkali-modified ZSM-5 zeolite obtained in step (1). The solvent was evaporated by heating in a water bath at 80 °C under stirring conditions and dried in an oven at 120 °C for 12 h. Subsequently, it was calcined in a muffle furnace at 550 °C for 4 h to obtain the iron-magnesium-modified ZSM-5 zeolite of this example; among them, iron accounts for 2% of the mass of the iron-magnesium-modified ZSM-5 zeolite, and magnesium accounts for 4% of the mass of the iron-magnesium-modified ZSM-5 zeolite.

[0119] The obtained iron-magnesium-modified ZSM-5 zeolite was used to prepare long-chain alkylnaphthalene. The preparation method of the long-chain alkylnaphthalene was the same as that in Example 1. The conversion rate of 1-octene in this example was 95%, and the selectivity was 96%.

[0120] Example 10

[0121] The preparation method of the iron-magnesium-modified ZSM-5 zeolite in this example includes the following steps:

[0122] (1) According to a molar ratio of tetrapropylammonium hydroxide to sodium hydroxide of 2, a mixed solution with an OH - content of 1.2 mol / L was prepared. 10 g of ZSM-5 zeolite with a silica-alumina ratio of 30 was added to the above mixed solution according to a solid-liquid ratio of 1 g:10 mL. It was stirred at 100 °C for 10 min, quenched in ice water, filtered, washed with deionized water until neutral, and the filter cake was dried at 140 °C for 16 h and then calcined in a muffle furnace at 700 °C for 3 h to obtain alkali-modified ZSM-5 zeolite;

[0123] (2) 1.62 g of iron nitrate and 1.81 g of magnesium chloride were dissolved in 40 mL of water, and the mixed solution was added to 10 g of the alkali-modified ZSM-5 zeolite obtained in step (1). The solvent was evaporated by heating in a water bath at 80 °C under stirring conditions and dried in an oven at 120 °C for 12 h. Subsequently, it was calcined in a muffle furnace at 550 °C for 4 h to obtain the iron-magnesium-modified ZSM-5 zeolite of this example; among them, iron accounts for 2% of the mass of the iron-magnesium-modified ZSM-5 zeolite, and magnesium accounts for 4% of the mass of the iron-magnesium-modified ZSM-5 zeolite.

[0124] The obtained iron- and magnesium-modified ZSM-5 molecular sieve was used to prepare long-chain alkylnaphthalenes. The preparation method of the long-chain alkylnaphthalenes was the same as that in Example 1. In this example, the conversion rate of 1-octene was 95%, and the selectivity was 95%.

[0125] Comparative Example 1

[0126] The preparation method of the magnesium-modified ZSM-5 molecular sieve in this comparative example included the following steps:

[0127] (1) The same as step (1) of Example 1 to obtain an alkali-modified ZSM-5 molecular sieve;

[0128] (2) An aqueous solution of magnesium chloride was added to the alkali-modified ZSM-5 molecular sieve obtained in step (1). Under stirring conditions, the solvent was evaporated by heating in a water bath at 80 °C, dried in an oven at 120 °C for 12 h, and then calcined in a muffle furnace at 550 °C for 4 h to obtain the magnesium-modified ZSM-5 molecular sieve of this comparative example; that is, in this comparative example, only magnesium was used to modify the ZSM-5 molecular sieve.

[0129] The magnesium-modified ZSM-5 molecular sieve of this comparative example was used to catalytically prepare long-chain alkylnaphthalenes. The preparation method of the long-chain alkylnaphthalenes was the same as that in Example 1. In this comparative example, the conversion rate of 1-octene was 83%, and the selectivity was 93%.

[0130] Comparative Example 2

[0131] The preparation method of the iron-modified ZSM-5 molecular sieve in this comparative example included the following steps:

[0132] (1) The same as step (1) of Example 1 to obtain an alkali-modified ZSM-5 molecular sieve;

[0133] (2) An aqueous solution of iron nitrate was added to the alkali-modified ZSM-5 molecular sieve obtained in step (1). Under stirring conditions, the solvent was evaporated by heating in a water bath at 80 °C, dried in an oven at 120 °C for 12 h, and then calcined in a muffle furnace at 550 °C for 4 h to obtain the iron-modified ZSM-5 molecular sieve of this comparative example; that is, in this comparative example, only iron was used to modify the ZSM-5 molecular sieve.

[0134] The iron-modified ZSM-5 molecular sieve of this comparative example was used to catalytically prepare long-chain alkylnaphthalenes. The preparation method of the long-chain alkylnaphthalenes was the same as that in Example 1. In this comparative example, the conversion rate of 1-octene was 84%, and the selectivity was 94%.

[0135] Comparative Example 3

[0136] In this comparative example, the ZSM-5 molecular sieve raw material with a silica-alumina ratio of 30 used in Example 1 was used as a catalyst to catalytically prepare long-chain alkylnaphthalenes. The preparation method of the long-chain alkylnaphthalenes was the same as that in Example 1. In this comparative example, the conversion rate of 1-octene was 72%, and the selectivity was 91%.

[0137] Comparative Example 4

[0138] In this comparative example, the alkali-modified ZSM-5 molecular sieve prepared in step (1) of Example 1 was used as a catalyst for the catalytic preparation of long-chain alkylnaphthalenes. The preparation method of long-chain alkylnaphthalenes was the same as that of Example 1. The conversion rate of 1-octene in this comparative example was 79%, and the selectivity was 92%.

[0139] Comparative Example 5

[0140] The preparation method of the iron-magnesium modified ZSM-5 molecular sieve in this comparative example includes the following steps:

[0141] (1) Prepare a sodium hydroxide solution with an OH - content of 0.45 mol / L. Take 10 g of ZSM-5 molecular sieve with a silica-alumina ratio of 30, add it to the above sodium hydroxide solution according to a solid-liquid ratio of 1 g:10 mL, stir at 80 °C for 1.5 h, quench in ice water, filter, wash with deionized water until neutral, dry the filter cake at 80 °C for 16 h, and then calcine it in a muffle furnace at 600 °C for 5 h to obtain an alkali-modified ZSM-5 molecular sieve;

[0142] (2) Dissolve 1.62 g of ferric nitrate and 1.81 g of magnesium chloride in 40 mL of water, and add the mixed solution to 10 g of the alkali-modified ZSM-5 molecular sieve obtained in step (1). Evaporate the solvent by heating in a water bath at 80 °C under stirring conditions, dry it in an oven at 120 °C for 12 h, and then calcine it in a muffle furnace at 550 °C for 4 h to obtain the iron-magnesium modified ZSM-5 molecular sieve of this example; wherein, iron accounts for 2% of the mass of the iron-magnesium modified ZSM-5 molecular sieve, and magnesium accounts for 4% of the mass of the iron-magnesium modified ZSM-5 molecular sieve.

[0143] The obtained iron-magnesium modified ZSM-5 molecular sieve was used to prepare long-chain alkylnaphthalenes. The preparation method of the long-chain alkylnaphthalenes was the same as that of Example 1. The conversion rate of 1-octene in this comparative example was 86%, and the selectivity was 94%.

[0144] Comparative Example 6

[0145] The preparation method of the iron-magnesium modified ZSM-5 molecular sieve in this comparative example includes the following steps:

[0146] (1) Prepare a tetrapropylammonium hydroxide solution with an OH - content of 0.45 mol / L. Take 10 g of ZSM-5 molecular sieve with a silica-alumina ratio of 30, add it to the above tetrapropylammonium hydroxide solution according to a solid-liquid ratio of 1 g:10 mL, stir at 80 °C for 1.5 h, quench in ice water, filter, wash with deionized water until neutral, dry the filter cake at 80 °C for 16 h, and then calcine it in a muffle furnace at 600 °C for 5 h to obtain an alkali-modified ZSM-5 molecular sieve;

[0147] (2) Dissolve 1.62 g of iron nitrate and 1.81 g of magnesium chloride in 40 mL of water, add the mixture to 10 g of the alkali-modified ZSM-5 molecular sieve obtained in step (1), evaporate the solvent by heating in a water bath at 80 °C under stirring conditions, dry in an oven at 120 °C for 12 h, and then calcine in a muffle furnace at 550 °C for 4 h to obtain the iron-magnesium modified ZSM-5 molecular sieve of this example; wherein, iron accounts for 2% of the mass of the iron-magnesium modified ZSM-5 molecular sieve, and magnesium accounts for 4% of the mass of the iron-magnesium modified ZSM-5 molecular sieve.

[0148] Use the obtained iron-magnesium modified ZSM-5 molecular sieve to prepare long-chain alkylnaphthalene. The preparation method of the long-chain alkylnaphthalene is the same as that in Example 1. The conversion rate of 1-octene in this Comparative Example 1 is 88%, and the selectivity is 94%.

[0149] Comparative Example 7

[0150] The preparation method of the magnesium-modified ZSM-5 molecular sieve in this comparative example includes the following steps:

[0151] (1) The same as step (1) of Example 5 to obtain an alkali-modified ZSM-5 molecular sieve;

[0152] (2) Add an aqueous solution of magnesium chloride to the alkali-modified ZSM-5 molecular sieve obtained in step (1), evaporate the solvent by heating in a water bath at 80 °C under stirring conditions, dry in an oven at 110 °C for 16 h, and then calcine in a muffle furnace at 550 °C for 5 h to obtain the magnesium-modified ZSM-5 molecular sieve of this comparative example; that is, only magnesium is used to modify the ZSM-5 molecular sieve in this comparative example.

[0153] Use the magnesium-modified ZSM-5 molecular sieve of this comparative example to catalytically prepare long-chain alkylnaphthalene. The preparation method of the long-chain alkylnaphthalene is the same as that in Example 5. The conversion rate of 1-hexadecene in this comparative example is 90%, and the selectivity is 95%.

[0154] Comparative Example 8

[0155] The preparation method of the iron-modified ZSM-5 molecular sieve in this comparative example includes the following steps:

[0156] (1) The same as step (1) of Example 5 to obtain an alkali-modified ZSM-5 molecular sieve;

[0157] (2) Add an aqueous solution of iron nitrate to the alkali-modified ZSM-5 molecular sieve obtained in step (1), evaporate the solvent by heating in a water bath at 80 °C under stirring conditions, dry in an oven at 110 °C for 16 h, and then calcine in a muffle furnace at 550 °C for 5 h to obtain the iron-modified ZSM-5 molecular sieve of this comparative example; that is, only iron is used to modify the ZSM-5 molecular sieve in this comparative example.

[0158] The iron-modified ZSM-5 molecular sieve of this comparative example was used in the catalytic preparation of long-chain alkylnaphthalenes. The preparation method of long-chain alkylnaphthalenes was the same as that in Example 5. In this comparative example, the conversion rate of 1-hexadecene was 86%, and the selectivity was 95%.

[0159] Comparative Example 9

[0160] In this comparative example, the ZSM-5 molecular sieve raw material with a silica-alumina ratio of 50 was used as a catalyst for the catalytic preparation of long-chain alkylnaphthalenes. The preparation method of long-chain alkylnaphthalenes was the same as that in Example 5. In this comparative example, the conversion rate of 1-hexadecene was 80%, and the selectivity was 93%.

[0161] Comparative Example 10

[0162] In this comparative example, the ZSM-5 molecular sieve raw material with a silica-alumina ratio of 200 was used as a catalyst for the catalytic preparation of long-chain alkylnaphthalenes. The preparation method of long-chain alkylnaphthalenes was the same as that in Example 5. In this comparative example, the conversion rate of 1-hexadecene was 70%, and the selectivity was 92%.

[0163] Comparative Example 11

[0164] The preparation method of the magnesium-lanthanum modified ZSM-5 molecular sieve in this comparative example includes the following steps:

[0165] (1) The same as step (1) of Example 5 to obtain an alkali-modified ZSM-5 molecular sieve;

[0166] (2) Dissolve 2.61 g of lanthanum nitrate and 2.73 g of magnesium chloride in 50 mL of water, and add this mixed solution to 15 g of the alkali-modified ZSM-5 molecular sieve obtained in step (1). Under stirring conditions, heat in a water bath at 80 °C to evaporate the solvent to dryness, dry in an oven at 110 °C for 16 h, and then calcine in a muffle furnace at 550 °C for 5 h to obtain the magnesium-lanthanum modified ZSM-5 molecular sieve of this example; wherein, lanthanum accounts for 2% of the mass of the magnesium-lanthanum modified ZSM-5 molecular sieve, and magnesium accounts for 4% of the mass of the magnesium-lanthanum modified ZSM-5 molecular sieve.

[0167] The magnesium-lanthanum modified ZSM-5 molecular sieve of this comparative example was used in the catalytic preparation of long-chain alkylnaphthalenes. The preparation method of long-chain alkylnaphthalenes was the same as that in Example 5. In this comparative example, the conversion rate of 1-hexadecene was 93%, and the selectivity was 94%.

[0168] Comparative Example 12

[0169] The preparation method of the iron-magnesium modified β molecular sieve of this example includes the following steps:

[0170] (1) Prepare OH according to a molar ratio of tetrapropylammonium hydroxide to sodium hydroxide of 0.4 -A mixed solution with a content of 0.45 mol / L was taken. 10 g of β-zeolite with a silica-alumina ratio of 80 was added to the above mixed solution according to a solid-liquid ratio of 1 g:10 mL. It was stirred at 80 °C for 1.5 h, quenched in ice water, filtered, washed with deionized water until neutral, and the filter cake was dried at 80 °C for 16 h and then calcined in a muffle furnace at 600 °C for 5 h to obtain the alkali-modified β-zeolite;

[0171] (2) 1.12 g of iron nitrate and 0.62 g of magnesium chloride were dissolved in methanol, and the mixed solution was added to 15 g of the alkali-modified β-zeolite obtained in step (1). The solvent was evaporated by heating in a water bath at 80 °C under stirring conditions, dried in an oven at 110 °C for 16 h, and then calcined in a muffle furnace at 600 °C for 5 h to obtain the iron-magnesium modified β-zeolite of this example; among them, iron accounted for 1% of the mass of the iron-magnesium modified β-zeolite, and magnesium accounted for 1% of the mass of the iron-magnesium modified β-zeolite.

[0172] The magnesium-lanthanum modified β-zeolite of this comparative example was used for the catalytic preparation of long-chain alkylnaphthalene. The preparation method of long-chain alkylnaphthalene was the same as that in Example 6. In this comparative example, the conversion rate of 1-octadecene was 90%, and the selectivity was 92%.

[0173] Comparative Example 13

[0174] The preparation method of the iron-magnesium modified ZSM-5 zeolite of this example includes the following steps:

[0175] (1) According to a molar ratio of tetrapropylammonium hydroxide to sodium hydroxide of 0.4, a mixed solution with an OH - content of 0.45 mol / L was prepared. 10 g of ZSM-5 zeolite with a silica-alumina ratio of 80 was added to the above mixed solution according to a solid-liquid ratio of 1 g:10 mL. It was stirred at 80 °C for 1.5 h, quenched in ice water, filtered, washed with deionized water until neutral, and the filter cake was dried at 80 °C for 16 h and then calcined in a muffle furnace at 600 °C for 5 h to obtain the alkali-modified ZSM-5 zeolite;

[0176] (2) 15.67 g of iron nitrate and 8.62 g of magnesium chloride were dissolved in 50 mL of methanol, and the mixed solution was added to 15 g of the alkali-modified ZSM-5 zeolite obtained in step (1). The solvent was evaporated by heating in a water bath at 80 °C under stirring conditions, dried in an oven at 110 °C for 16 h, and then calcined in a muffle furnace at 600 °C for 5 h to obtain the iron-magnesium modified ZSM-5 zeolite of this example; among them, iron accounted for 10% of the mass of the iron-magnesium modified ZSM-5 zeolite, and magnesium accounted for 10% of the mass of the iron-magnesium modified ZSM-5 zeolite.

[0177] The iron-magnesium modified ZSM-5 zeolite of this comparative example was used for the catalytic preparation of long-chain alkylnaphthalene. The preparation method of long-chain alkylnaphthalene was the same as that in Example 6. In this comparative example, the conversion rate of 1-octadecene was 60%, and the selectivity was 88%.

[0178] In summary, the Fe-Mg modified ZSM-5 molecular sieve provided by the present invention can be used in the alkylation reaction of long-chain olefins and naphthalene to prepare long-chain alkylnaphthalenes, with high conversion rate and selectivity, recyclable, and capable of simultaneously preparing alkylnaphthalene-based lubricating oil base oils with two viscosities, having industrial practical application value.

[0179] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A preparation method of an iron and magnesium modified ZSM-5 molecular sieve, characterized in that, It includes the following steps: (1) Mix and modify a mixed solution of an organic base and an inorganic base with ZSM-5 molecular sieve, wash, dry, and calcine to obtain an alkali-modified ZSM-5 molecular sieve; (2) Mix and dissolve an iron salt, a magnesium salt, and the alkali-modified ZSM-5 molecular sieve obtained in step (1) in a solvent, evaporate the solvent to dryness, dry, and calcine to obtain the iron-magnesium-modified ZSM-5 molecular sieve.

2. The preparation method of the iron-magnesium modified ZSM-5 molecular sieve according to claim 1, characterized in that, The organic base includes tetrapropylammonium hydroxide, and the inorganic base includes sodium hydroxide; the concentration of OH - in the mixed solution is 0.1 mol / L - 1.2 mol / L.

3. The preparation method of the iron-magnesium modified ZSM-5 molecular sieve according to claim 1, characterized in that, In step (1), the solid-liquid ratio of the ZSM-5 molecular sieve to the mixed solution of the organic base and the inorganic base is 1 g:(5 - 20) mL.

4. The preparation method of the iron-magnesium modified ZSM-5 molecular sieve according to claim 1, characterized in that, In step (1), the temperature of the mixed modification is 50°C - 100°C, and the time is 10 min - 240 min; and / or, the temperature of the drying is 60°C - 140°C; and / or, the temperature of the calcination is 400°C - 700°C, and the time is 3 h - 10 h.

5. The preparation method of the iron-magnesium modified ZSM-5 molecular sieve according to claim 1, characterized in that, The iron salt includes at least one of ferric nitrate, ferric sulfate, and ferric chloride; the magnesium salt includes at least one of magnesium nitrate, magnesium sulfate, and magnesium chloride; the silica-alumina ratio of the ZSM-5 molecular sieve is 5 - 500.

6. The preparation method of the iron-magnesium modified ZSM-5 molecular sieve according to claim 1, characterized in that, In the iron-magnesium-modified ZSM-5 molecular sieve, the iron accounts for 0.2% - 8% of the mass of the iron-magnesium-modified ZSM-5 molecular sieve, and the magnesium accounts for 0.2% - 8% of the mass of the iron-magnesium-modified ZSM-5 molecular sieve.

7. The preparation method of the iron-magnesium modified ZSM-5 molecular sieve according to claim 1, characterized in that, In step (2), the temperature of the drying is 60°C - 140°C, and the time is 8 h - 24 h; and / or, the temperature of the calcination is 400°C - 700°C, and the time is 3 h - 10 h.

8. The iron-magnesium-modified ZSM-5 molecular sieve prepared by the preparation method of the iron-magnesium-modified ZSM-5 molecular sieve according to any one of claims 1 - 7.

9. The application of the iron-magnesium-modified ZSM-5 molecular sieve according to claim 8 in the catalytic preparation of long-chain alkylnaphthalene.

10. A method for preparing long-chain alkylnaphthalene, characterized in that, It includes the following steps: (1) In the presence of the iron-magnesium-modified ZSM-5 molecular sieve according to claim 9, carry out an alkylation reaction between naphthalene and a long-chain olefin to obtain a crude product of alkylnaphthalene; (2) Filter the crude product of alkylnaphthalene obtained in step (1) to remove the solid catalyst, and then remove the unreacted long-chain olefin and naphthalene completely. The obtained solution is heated and decolorized using activated clay, and the activated clay is removed after decolorization to obtain a first kind of alkylnaphthalene; (3) Carry out vacuum distillation on the first kind of alkylnaphthalene obtained in step (2) to obtain a second kind of alkylnaphthalene.