Catalyst and preparation method, preparation method of diisopropyl naphthalene heat conducting oil and prepared diisopropyl naphthalene heat conducting oil

Abstract

The application provides a catalyst and a preparation method thereof, a preparation method of diisopropyl naphthalene heat conducting oil and the prepared diisopropyl naphthalene heat conducting oil. The application provides a preparation method of a catalyst, which comprises the following steps: mixing HUSY molecular sieve and a citric acid solution, reacting, separating to obtain a solid product, and washing and drying the solid product to obtain the catalyst, wherein the concentration of the citric acid solution is 0.1-0.5 mol / L. The application provides a catalyst which is prepared by the reaction of a citric acid solution and HUSY molecular sieve. In the reaction process, the concentration of the citric acid solution is controlled, so that the internal pore channels of the molecular sieve can be dredged after the reaction of the citric acid solution and the molecular sieve, the content of micropores is increased, the content of strong acid and B acid on the surface of the molecular sieve is increased, and therefore the activity and selectivity of the catalyst are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of heat transfer oil preparation, specifically to catalysts and preparation methods, preparation methods of diisopropylnaphthalene heat transfer oil, and the prepared diisopropylnaphthalene heat transfer oil. Background Technology

[0002] Diisopropylnaphthalene (DIPN) is an important chemical product, raw material, and intermediate, widely used in the synthesis of fine chemicals. Due to its numerous advantages such as being colorless and odorless, having a high boiling point, and strong dissolving power, DIPN is widely used as a solvent in the carbonless copy paper and ink industry, coatings and paints, adhesives, and other industries. It can also be used as a plant growth regulator in agricultural production. Furthermore, it is a high-performance high-temperature synthetic heat-conducting oil and electrical insulating oil. In addition, DIPN is an important chemical raw material that can be used to prepare monomers for high-performance polyester fibers and thermotropic liquid crystal polymers.

[0003] Current research on DIPN synthesis mainly focuses on the screening of alkylation catalysts and the shape-selective catalysis of DIPN using molecular sieve catalysts. Research on alkylation catalysts largely concentrates on solid acid catalysts. For example, Chen et al. used aluminosilicate as a catalyst to prepare diisopropylnaphthalene, and by optimizing the process conditions, they obtained 23.1% DIPN. Shape-selective catalysis research focuses on molecular sieve catalysts. Numerous reports indicate that hydrogen-form Y molecular sieves (HY) and hydrogen-form mordenite (HM) exhibit the best performance among catalysts for DIPN preparation. This is mainly because the molecular size of DIPN is comparable to the pore size of these molecular sieves, allowing product molecules to freely pass through the sieve pores to contact the active sites inside the sieve and diffuse freely, while the free diffusion of larger isomers is hindered.

[0004] However, using solid acids or existing molecular sieves as catalysts can lead to severe equipment corrosion, complex post-processing of products, high environmental pressure, and does not meet the requirements of green chemical development.

[0005] Since the 1980s, a prominent feature of the development of cracking catalysts abroad has been the rapid development and widespread application of USY ultrastable catalysts, which, according to statistics, now account for 60%. USY molecular sieves have wide industrial applications in catalytic cracking, olefin alkylation, alkyl transfer, and gas adsorption separation. With the trend towards low-lead or lead-free gasoline, ultrastable USY molecular sieves have entered the catalytic cracking arena and have been rapidly adopted. This is mainly because using this zeolite molecular sieve as a catalyst can reduce hydrogen transfer reactions, increase the olefin content and octane number in gasoline, reduce coke yield, and improve light oil yield and throughput. However, due to its still relatively low and difficult-to-control silicon-to-aluminum ratio, numerous lattice defects, and the fact that removed aluminum remains within the molecular sieve cages, the migration of aluminum from the outermost layer to the outermost layer leads to uneven distribution of bulk aluminum and enrichment of amorphous aluminum surfaces. This, in turn, promotes coking and excessive cracking, hindering further improvement in selectivity.

[0006] Therefore, there is an urgent need in the existing technology for a catalyst with good catalyst performance and selectivity in the preparation of diisopropylnaphthalene heat transfer oil. Summary of the Invention

[0007] To address the aforementioned problems in the prior art, this invention proposes a catalyst and its preparation method, a method for preparing diisopropylnaphthalene heat-conducting oil, and the prepared diisopropylnaphthalene heat-conducting oil.

[0008] In a first aspect, the present invention provides a method for preparing a catalyst, the method comprising: mixing HUSY molecular sieve with citric acid solution, reacting and separating to obtain a solid product, washing and drying the solid product to obtain the catalyst, wherein the concentration of the citric acid solution is 0.1-0.5 mol / L.

[0009] This invention relates to the preparation of a catalyst using a mixture of citric acid aqueous solution and HUSY molecular sieve. By controlling the concentration of the citric acid solution, this invention enables the citric acid to remove more easily eluted species such as non-framework aluminum from the molecular sieve during the reaction, thereby expanding the pores of the molecular sieve without significantly damaging its framework. Furthermore, by controlling the concentration of citric acid in the mixture, the content of strong acids and Brønsted acids on the surface of the molecular sieve can be increased. When the content of strong acids and Brønsted acids on the surface of the molecular sieve reaches a certain level, the catalyst exhibits improved activity and selectivity in the process of catalyzing the reaction of naphthalene and propylene to prepare diisopropylnaphthalene.

[0010] This invention reveals that mixing citric acid with HUSY molecular sieves at different concentrations results in varying elution effects of citric acid on non-framework species within the sieve. At lower concentrations, the reaction of citric acid with HUSY molecular sieves preferentially removes framework-less and amorphous aluminum from the sieve pores, clearing blockages and effectively increasing micropore content. However, its effect on increasing the content of moderately strong acids and Brønsted acids in the catalyst is limited. Therefore, at lower concentrations, the catalyst used to catalyze the reaction of naphthalene and propylene to prepare diisopropylnaphthalene does not show significant improvement in naphthalene conversion or selectivity. Appropriately increasing the concentration of citric acid allows the reaction to clear blockages within the molecular sieve, increasing both the micropore content and the surface content of moderately strong acids and Brønsted acids, thus achieving optimal catalytic performance. When the concentration of citric acid is too high, the citric acid reacts with the molecular sieve, removing aluminum from the molecular sieve framework, destroying the molecular sieve lattice structure, and reducing the content of strong acid and Brønsted acid in the molecular sieve, thus reducing the activity and selectivity of the catalyst.

[0011] As a specific embodiment of the present invention, the mass ratio of HUSY molecular sieve to citric acid solution is 1:1 to 16; preferably 1:4 to 10.

[0012] As a specific embodiment of the present invention, the reaction conditions of HUSY molecular sieve and citric acid solution include: temperature of 80-100°C and time of 2-5 hours.

[0013] As a specific embodiment of the present invention, the concentration of the citric acid solution is 0.2 to 0.5 mol / L.

[0014] As a specific embodiment of the present invention, HUSY molecular sieve is prepared by the following method:

[0015] (1) Mix NaY molecular sieve with NH4Cl solution, stir, separate and dry to obtain NH4Y molecular sieve;

[0016] Optionally, the process of obtaining NH4Y molecular sieve is repeated at least once in step (1);

[0017] (2) The NH4Y molecular sieve was calcined to obtain the HUSY molecular sieve.

[0018] Optionally, the process of obtaining HUSY molecular sieves is repeated at least once, steps (1) to (2).

[0019] Specifically, for the process of obtaining NH4Y molecular sieve, the process of repeating step (1) once is as follows: mix NaY molecular sieve with NH4Cl solution, stir, separate and dry to obtain solid product, mix the solid product with NH4Cl solution again, stir, separate and dry to obtain NH4Y molecular sieve.

[0020] Specifically, for the process of obtaining HUSY molecular sieve, the process of repeating steps (1) to (2) once is as follows: calcining NH4Y molecular sieve to obtain calcined product, mixing the calcined product with NH4Cl solution, stirring, separating and drying to obtain solid product, mixing the solid product with NH4Cl solution again, stirring, separating and drying to obtain NH4Y molecular sieve, and calcining NH4Y molecular sieve to obtain HUSY molecular sieve.

[0021] As a specific embodiment of the present invention, the stirring conditions in step (1) include: a temperature of 70 to 100°C and a time of 50 to 70 minutes.

[0022] As a specific embodiment of the present invention, in step (1), with the mass of NaY molecular sieve being 100g, the volume of NH4Cl solution is 0.8-1.2L and the concentration is 0.8-1.2mol / L.

[0023] As a specific embodiment of the present invention, the roasting conditions in step (2) include: a temperature of 550 to 650°C, a time of 3 to 5 hours, and a roasting atmosphere of water vapor.

[0024] In a second aspect, the present invention provides a catalyst prepared using the preparation method provided in the first aspect of the present invention.

[0025] In a specific embodiment of the present invention, the catalyst has a specific surface area of ​​600–850 m². 2 / g.

[0026] Thirdly, the present invention provides a method for preparing diisopropylnaphthalene heat transfer oil, wherein a raw material containing naphthalene source and propylene is reacted to obtain diisopropylnaphthalene heat transfer oil in the presence of a catalyst prepared by the catalyst preparation method provided in the first aspect of the present invention or a catalyst provided in the second aspect of the present invention.

[0027] As a specific embodiment of the present invention, the amount of catalyst used is 3 to 11 wt% of the total mass of naphthalene source and propylene, preferably 4 to 8 wt%.

[0028] As a specific embodiment of the present invention, the reaction conditions between naphthalene source and propylene include: temperature of 160-260°C, pressure of 1.2-4 MPa, and reaction time of 6-9 hours.

[0029] Preferably, the reaction between the naphthalene source and propylene is carried out under stirring conditions, with a stirring speed of 200–800 rpm / min.

[0030] In a specific embodiment of the present invention, the naphthalene source is naphthalene or 2-isopropylnaphthalene.

[0031] In a specific embodiment of the present invention, the molar ratio of naphthalene source to propylene is 1:1 to 8.

[0032] In a specific embodiment of the present invention, the conversion rate of the naphthalene source in the preparation method is 95% to 98%, and the selectivity of diisopropylnaphthalene is 66% to 78%.

[0033] Fourthly, the present invention provides a diisopropylnaphthalene heat-conducting oil, prepared using the preparation method provided in the second aspect of the present invention; the kinematic viscosity of the diisopropylnaphthalene heat-conducting oil at 100°C is 1.7–1.9 mm. 2 / s, pour point is -45 to -47℃.

[0034] Compared with the prior art, the present invention has the following beneficial effects.

[0035] This invention provides a method for preparing a catalyst by reacting a citric acid solution with a HUSY molecular sieve. During the reaction, by controlling the concentration of the citric acid solution, the reaction can open up the internal pores of the molecular sieve, increasing the micropore content, and simultaneously increasing the content of strong acids and Brønsted acids on the surface of the HUSY molecular sieve, thereby effectively improving the activity and selectivity of the catalyst.

[0036] In this invention, citric acid is used to treat HUSY molecular sieves. Compared with treating HUSY molecular sieves with other acids, this method can more effectively increase the amount of Brønsted acid on the surface of HUSY molecular sieves, thereby improving the activity and selectivity of the catalyst.

[0037] The catalyst provided by this invention exhibits high catalytic activity, high selectivity for diisopropylnaphthalene, and high conversion rate of propylene when applied to the reaction of naphthalene and propylene.

[0038] The catalyst in this invention can achieve excellent catalytic effects even with a low catalyst dosage.

[0039] This invention provides a diisopropylnaphthalene heat transfer oil with high safety standards for storage, transportation, and operation. It also exhibits good flow properties at low temperatures and will not cause acid corrosion to equipment during use. Detailed Implementation

[0040] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0041] The raw materials used in all embodiments of this invention are commercially available, wherein

[0042] NaY molecular sieves were purchased from the catalyst factory of Nankai University, product number NKF-7SC;

[0043] Nitric acid, purity ≥90wt%, purchased from Alorich Chemistry, CAS No. 7697-37-2;

[0044] Ammonium chloride (NH4Cl), purity ≥90wt%, purchased from Alorich Chemistry, CAS No. 12125-02-9;

[0045] Citric acid monohydrate (C6H8O7·H2O) was purchased from Sinopharm Chemical Reagent Co., Ltd., CAS No. 5949-29-1;

[0046] Sodium ethylenediaminetetraacetate (C 10 H 16 N2Na2O8 (EDTA-Na), purchased from Sinopharm Chemical Reagent Co., Ltd., CAS No. 139-33-3;

[0047] The deionized water was prepared in the laboratory.

[0048] Both propylene and naphthalene were sourced from the refining and chemical unit of Sinopec Maoming Petrochemical Company. The purity of propylene was 65-70 wt%, and the purity of naphthalene was 95 wt%.

[0049] Preparation Example 1

[0050] (1) Mix 100g of NaY molecular sieve with 1000mL of 1mol / L NH4Cl solution, heat and stir at 80℃ for 1h, then filter and wash, collect the solid product, mix the solid product with 1000mL of 1mol / L NH4Cl solution, heat and stir at 80℃ for 1h, collect the solid product, mix the solid product with 1000mL of 1mol / L NH4Cl solution, heat and stir at 80℃ for 1h, collect the solid product, and dry the solid product in an oven at 120℃ for 12h to obtain NH4Y molecular sieve.

[0051] (2) Place the NH4Y molecular sieve in a tube furnace, heat it to 600℃, and calcine it for 3 hours in a 100% steam atmosphere to obtain the calcined product.

[0052] (3) Repeat steps (1) to (2) twice with the calcined product to obtain HUSY molecular sieve.

[0053] (4) HUSY molecular sieve was impregnated in a 0.2 mol / L citric acid (C6H8O7·H2O) solution to obtain a suspension. The mass ratio of HUSY molecular sieve to citric acid solution was 1:8. The suspension was heated in a water bath at 90°C for 2 hours. After filtration and washing with deionized water, the filtrate was separated by suction filtration until it was neutral when tested with pH paper. The filter cake was recovered, dried at 100°C under normal pressure for 12 hours, and then ground to obtain 0.2 mol / L citric acid-treated HUSY molecular sieve, labeled as 0.2N-HUSY.

[0054] Preparation Example 2

[0055] Based on Preparation Example 1, Preparation Example 2 was set up. The difference between Preparation Example 2 and Preparation Example 1 was that the HUSY molecular sieve was immersed in a 0.5 mol / L citric acid (C6H8O7·H2O) solution. The HUSY molecular sieve treated with 0.5 mol / L citric acid was obtained and labeled as 0.5N-HUSY.

[0056] Preparation Example 3

[0057] Based on Preparation Example 1, Preparation Example 3 was set up. The difference between Preparation Example 3 and Preparation Example 1 was that the HUSY molecular sieve was immersed in a 0.7 mol / L citric acid (C6H8O7·H2O) solution. The HUSY molecular sieve treated with 0.7 mol / L citric acid was obtained and labeled as 0.7N-HUSY.

[0058] Preparation Example 4

[0059] Based on Preparation Example 1, Preparation Example 4 was set up. The difference between Preparation Example 4 and Preparation Example 1 is that the HUSY molecular sieve was immersed in a 1 mol / L citric acid (C6H8O7·H2O) solution. The 1 mol / L citric acid-treated HUSY molecular sieve was obtained and labeled as 1N-HUSY.

[0060] Preparation Example 5

[0061] Based on Preparation Example 1, Preparation Example 5 was set up. The difference between Preparation Example 5 and Preparation Example 1 is that HUSY molecular sieve was immersed in a 1.2 mol / L citric acid (C6H8O7·H2O) solution to obtain 1.2 mol / L citric acid treated HUSY molecular sieve, which was labeled as 1.2N-HUSY.

[0062] Preparation Example 6

[0063] Based on Preparation Example 1, Preparation Example 6 was set up. The difference between Preparation Example 6 and Preparation Example 1 is that HUSY molecular sieve was impregnated in a 0.8 mol / L EDTA-Na aqueous solution to obtain a suspension. The mass ratio of HUSY molecular sieve to EDTA-Na aqueous solution was 1:8. The suspension was heated in a water bath at 90°C for 2 hours. After filtration and washing with deionized water, the filtrate was separated by vacuum filtration and tested with pH paper until it was neutral. The filter cake was recovered, dried at 100°C under normal pressure for 12 hours, and then calcined in a muffle furnace at 500°C for 5 hours in air atmosphere to obtain 0.8 mol / L EDTA-treated HUSY molecular sieve, labeled as 0.8M / EDTA-HUSY.

[0064] Example 1

[0065] (1) Place naphthalene in a reaction vessel, and then add 0.5N-HUSY molecular sieve catalyst. The amount of catalyst is 5wt% of the total mass of naphthalene and propylene.

[0066] (2) As the temperature increases, the stirring speed is increased. When the temperature reaches the predetermined reaction temperature of 200℃, the stirring speed is set to 600 rpm. Propylene is introduced into the reactor, with a molar ratio of naphthalene to propylene of 1:5. A micro-pump for propylene is used, and the flow rate is set to 20 mL / h. The underpressure compensation of the reactor is set to 1.0 MPa, the overpressure protection of the reactor is set to 4.0 MPa, the reaction pressure is set to 3 MPa, and the reaction time is set to 8 h.

[0067] (3) After the reaction is stopped, the substance in the reactor is removed, filtered, and the filtrate is the heat transfer oil, and the solid product is the catalyst. The catalyst is recovered, and the heat transfer oil is depressurized to 900 Pa and distilled at 80 °C to remove the unreacted naphthalene. Monoisopropylnaphthalene is collected at 1000 Pa and 70-110 °C, and diisopropylnaphthalene is collected at 1800 Pa and 120-260 °C.

[0068] (4) The recovered catalyst is washed with ethyl acetate and dried. The reaction to prepare heat transfer oil is carried out in steps (1) to (3) in this way, and the catalyst is reused 10 times.

[0069] Example 2

[0070] The synthesis method of the heat transfer oil in Example 2 is the same as that in Example 1, except that the catalyst is replaced with 0.2N-HUSY. The catalyst is also reused 10 times.

[0071] Example 3

[0072] The synthesis method of the heat transfer oil in Example 3 is the same as that in Example 1, except that the amount of catalyst is adjusted to 4 wt% of the total mass of naphthalene and propylene. The catalyst is also reused 10 times.

[0073] Comparative Example 1

[0074] The heat transfer oil in Comparative Example 1 was synthesized using the same method as in Example 1, except that the catalyst was replaced with the HUSY molecular sieve prepared in Preparation Example 1. The catalyst was also reused 10 times.

[0075] Comparative Example 2

[0076] The heat transfer oil in Comparative Example 2 was synthesized using the same method as in Example 1, except that the catalyst was replaced with 1.2N-HUSY molecular sieve. The catalyst was also reused 10 times.

[0077] Comparative Example 3

[0078] The heat transfer oil in Comparative Example 3 was synthesized using the same method as in Example 1, except that the catalyst was replaced with a 0.8M / EDTA-HUSY molecular sieve catalyst. The catalyst was also reused 10 times.

[0079] Comparative Example 4

[0080] The heat transfer oil of Comparative Example 4 was synthesized using the same method as in Example 1, except that the catalyst was replaced with 1N-HUSY. The catalyst was also reused 10 times.

[0081] Comparative Example 5

[0082] The heat transfer oil of Comparative Example 5 was synthesized using the same method as in Example 1, except that the catalyst was replaced with 0.7N-HUSY. The catalyst was also reused 10 times.

[0083] Testing and characterization methods:

[0084] The products were qualitatively and quantitatively analyzed by gas chromatography. The instrument was a Shanghai Kechuang Chromatography Co., Ltd. 900A with an FID detector. The carrier gas was nitrogen, the injection volume was 2 μL, the split ratio was 50:1, and the column was a 60m AC-10 capillary column (Australia). The chromatographic program was set as follows: stabilize at 140℃ for 5 min, increase to 170℃ at 3℃ / min and stabilize for 14 min, increase to 210℃ at 4℃ / min and stabilize for 7 min, and finally increase to 230℃ at 8℃ / min and stabilize for 10 min.

[0085] The substances corresponding to the spectral peaks were identified together using a Finnigan MD800 chromatograph-mass spectrometer from the Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences.

[0086] Conversion rate of naphthalene = (Number of moles of naphthalene converted / Total number of moles of naphthalene) × 100%

[0087] Diisopropylnaphthalene selectivity = (number of moles of diisopropylnaphthalene in the product / total number of moles of the product) × 100%

[0088] This invention uses a distillation method to test the purity of the product.

[0089] The flash point (open cup) performance test shall be performed in accordance with the test method of GB / T3536-2008 "Determination of flash point and fire point of petroleum products";

[0090] The pour point performance test shall be performed in accordance with the test method of GB / T3535-2006 "Petroleum Pour Point Determination".

[0091] The acid value test shall be performed in accordance with the test method of GB / T4945-2002 "Determination of Acid Value and Base Value of Petroleum Products and Lubricants (Color Indication Method)";

[0092] Density testing shall be performed in accordance with GB / T1884-2000 "Determination of Density of Petroleum Products" and GB / T 1885-1998 "Petroleum Measurement Tables";

[0093] The kinematic viscosity shall be tested in accordance with the method specified in GB / T265-1988 "Determination of Kinematic Viscosity of Petroleum Products".

[0094] The specific surface area of ​​the catalyst was determined using the nitrogen adsorption BET specific surface area assay.

[0095] Table 1. Specific surface area test results of the catalysts used in the examples and comparative examples.

[0096] Specific surface area Example 1 <![CDATA[810~830m 2 / g]]> Example 2 <![CDATA[660~664m 2 / g]]>

[0097] Note that the catalyst specific surface area test results in Table 1 are range values ​​obtained from multiple measurements of catalysts prepared in the same embodiment or comparative example.

[0098] Table 2. Conversion rate of naphthalene during the reaction processes of the examples and comparative examples.

[0099]

[0100] Table 3. Selectivity of diisopropylnaphthalene during the reactions of the examples and comparative examples.

[0101]

[0102] Table 4 shows the performance of the heat transfer oils prepared in the examples.

[0103]

[0104] As shown in Tables 1 and 2, the methods for preparing 2,diisopropylnaphthalene through the isopropylation reaction of naphthalene with propylene in all embodiments of the present invention achieve high naphthalene conversion rates and diisopropylnaphthalene selectivity, with a naphthalene conversion rate reaching 98.4%. After 10 uses, there was no significant decrease in naphthalene conversion. Table 3 shows that the heat transfer oil has a very high flash point, indicating that the heat transfer oil prepared by the present invention has high safety indicators for general storage, transportation, and operation. The pour point is below -50°C, indicating that the heat transfer oil prepared by the present invention has good flow properties at low temperatures. The acid value is close to 0, indicating that the heat transfer oil prepared by the present invention will not cause acid corrosion to equipment during use.

[0105] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for preparing a catalyst, characterized in that, The catalyst preparation method includes: mixing HUSY molecular sieve with citric acid solution, reacting and separating to obtain a solid product, washing and drying the solid product to obtain the catalyst, wherein the concentration of the citric acid solution is 0.1-0.5 mol / L.

2. The method for preparing the catalyst according to claim 1, characterized in that, The mass ratio of the HUSY molecular sieve to the citric acid solution is 1:1 to 16; preferably 1:4 to 10. And / or, the reaction conditions of the HUSY molecular sieve with citric acid solution include: a temperature of 80-100°C and a time of 2-5 hours; And / or, the concentration of the citric acid solution is 0.2 to 0.5 mol / L.

3. The method for preparing the catalyst according to claim 1 or 2, characterized in that, The HUSY molecular sieve is prepared using the following method: (1) Mix NaY molecular sieve with NH4Cl solution, stir, separate and dry to obtain NH4Y molecular sieve; Optionally, the process of obtaining NH4Y molecular sieve is repeated at least once in step (1); (2) The NH4Y molecular sieve was calcined to obtain the HUSY molecular sieve. Optionally, the process of obtaining the HUSY molecular sieve is to repeat steps (1) to (2) at least once.

4. The method for preparing the catalyst according to claim 3, characterized in that, The stirring conditions in step (1) include: a temperature of 70-100℃ and a time of 50-70 min; And / or, in step (1), based on a mass of 100g of NaY molecular sieve, the volume of the NH4Cl solution is 0.8-1.2L and the concentration is 0.8-1.2mol / L; And / or, the roasting conditions in step (2) include: a temperature of 550 to 650°C, a time of 3 to 5 hours, and a roasting atmosphere of steam.

5. A catalyst, characterized in that, Prepared by the preparation method according to any one of claims 1 to 4.

6. The catalyst according to claim 5, characterized in that, The catalyst has a specific surface area of ​​600–850 m². 2 / g.

7. A method for preparing a diisopropylnaphthalene heat-conducting oil, characterized in that, The diisopropylnaphthalene heat transfer oil is obtained by reacting a raw material containing naphthalene source and propylene in the presence of a catalyst prepared by the preparation method according to any one of claims 1 to 4 or the catalyst according to claim 5 or 6.

8. The method for preparing the heat transfer oil according to claim 7, characterized in that, The amount of catalyst used is 3 to 11 wt% of the total mass of the naphthalene source and propylene, preferably 4 to 8 wt%. And / or, the reaction conditions between naphthalene source and propylene include: temperature of 160–260 °C, pressure of 1.2–4 MPa, and reaction time of 6–9 hours; Preferably, the reaction between the naphthalene source and propylene is carried out under stirring conditions, with a stirring speed of 200–800 rpm / min.

9. The method for preparing the heat transfer oil according to claim 7 or 8, characterized in that, The naphthalene source is naphthalene or 2-isopropylnaphthalene; And / or, the molar ratio of the naphthalene source to propylene is 1:1 to 8; And / or, in the preparation method, the conversion rate of the naphthalene source is 95%–98%, and the selectivity of diisopropylnaphthalene is 66%–78%.

10. A diisopropylnaphthalene heat transfer oil, characterized in that, The diisopropylnaphthalene heat transfer oil is prepared using the preparation method described in any one of claims 7 to 9; the kinematic viscosity of the diisopropylnaphthalene heat transfer oil at 100°C is 1.7–1.9 mm. 2 / s, pour point is -45 to -47℃.

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