Synthesis method and application of isopropyl naphthalene
By using a composite catalyst supported on molecular sieves with SO42-, the problems of low catalyst activity and poor stability were solved, and the efficient preparation of isopropylnaphthalene heat transfer oil with low viscosity, low pour point and good thermal stability was achieved, making it suitable for high-temperature environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-12-06
- Publication Date
- 2026-06-09
AI Technical Summary
Existing catalysts exhibit low reactivity, low selectivity, and poor stability in the preparation of isopropylnaphthalene, and are prone to deactivation, making it difficult to achieve continuous preparation of diisopropylnaphthalene.
By employing a composite catalyst, including a molecular sieve and SO42- supported on the molecular sieve, and by improving the catalyst and synthesis process conditions, the conversion rate and selectivity of the isopropylation reaction of naphthalene and propylene are enhanced, resulting in the preparation of an isopropyl naphthalene heat transfer oil with low viscosity, low pour point, and good thermal stability.
A high conversion rate and high selectivity for the preparation of isopropylnaphthalene were achieved. The catalyst exhibits good reproducibility and can be reused. The prepared isopropylnaphthalene heat transfer oil has low viscosity, low pour point, and good thermal stability, making it suitable for high-temperature environments.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of lubricating oil technology, and specifically to a method for synthesizing isopropyl naphthalene and its application. Background Technology
[0002] With the continuous development of the petrochemical and energy industries, the demand for high-temperature heating is increasing due to the iterative upgrading of new technologies and processes. High-temperature synthetic heat transfer oils offer advantages such as high initial boiling point and narrow distillation range, less high-temperature cracking during the reaction, and good high-temperature thermal stability. However, they also have high production costs, high prices, high technological content, low volatility, recyclability, and a service life of 5-10 years. As the advantages of high-temperature synthetic heat transfer oils are recognized and unit production costs decrease, they will gradually replace mineral-based heat transfer oils as the mainstream product in the market. Among them, isopropylnaphthalene (diisopropylnaphthalene, triisopropylnaphthalene) is an excellent heat transfer oil.
[0003] Diisopropylnaphthalene, a high-temperature synthetic heat transfer oil made from naphthalene and propylene / isopropanol, possesses advantages such as being odorless, non-corrosive to metals, having good thermal stability, excellent low-temperature performance, and being recyclable. Its good thermal stability allows it to operate continuously at high temperatures of 320–330°C. It also has a low pour point, is non-corrosive, has no unpleasant odor, and is easy to use, making it a high-performance high-temperature synthetic heat transfer oil. Therefore, it can be widely used in industries such as petrochemicals, automotive transportation, power and electrical engineering, textile printing and dyeing, and energy.
[0004] Currently, the synthesis of diisopropylnaphthalene generally employs a liquid-phase alkylation method using naphthalene and propylene / isopropanol. Zhong Haijun et al. (Industrial Catalysis, 2007, Vol. 15, No. 7) used a high-pressure reactor with Hβ molecular sieve as the catalyst, a naphthalene:isopropanol ratio of 1:2.5, and after 8 hours of reaction, the naphthalene conversion was 69.05%, and the molar ratio of triisopropylnaphthalene to the product was 18.39%. Chu et al. (Applied Catalysis A: General 123 (1995) 51-58) found that using ultrastable Y zeolite molecular sieve as the catalyst, the naphthalene conversion decreased from 100% to 92% after 6 hours of reaction at 200℃; using β zeolite molecular sieve as the catalyst, the naphthalene conversion decreased from 94% to 62%; and using mordenite zeolite as the catalyst, the naphthalene conversion decreased from 68% to 20%. Currently, the isopropylation of naphthalene mostly employs batch reactor or fixed-bed reactor processes, during which the catalyst is very easily deactivated (Journal of Catalysis 220 (2003) 265-272), making it difficult to achieve continuous preparation of diisopropylnaphthalene. Summary of the Invention
[0005] The technical problem to be solved by this invention is that existing catalysts used to prepare isopropyl naphthalene have low reactivity, low selectivity for diisopropyl naphthalene, poor catalyst stability, and are prone to deactivation. This invention provides a method for synthesizing isopropyl naphthalene and its application. By improving the catalyst and synthesis process conditions, the isopropylation reaction of naphthalene with propylene is improved, thereby increasing the conversion rate of naphthalene and the selectivity of diisopropyl naphthalene. At the same time, an isopropyl naphthalene heat transfer oil with low viscosity, low pour point, and good thermal stability is synthesized.
[0006] To solve the above-mentioned technical problems, the first aspect of the present invention provides a method for synthesizing isopropylnaphthalene, comprising reacting a naphthalene source and an alkylating agent under an inert atmosphere and in the presence of a composite catalyst to obtain isopropylnaphthalene;
[0007] The composite catalyst comprises a molecular sieve and SO4 supported on the molecular sieve. 2- Based on the mass of the composite catalyst being 100%, the SO4 2- The mass fraction is 2% to 11%.
[0008] According to some embodiments of the present invention, the molecular sieve is selected from at least one of Y molecular sieve, ZSM-5 molecular sieve, and MCM-22 molecular sieve.
[0009] According to some embodiments of the present invention, based on the mass of the composite catalyst being 100%, the SO4 2- The mass fraction is 3% to 10%.
[0010] The composite catalyst described in this invention, namely SO4 2- / Molecular sieve composite catalysts are used as catalysts for isopropylation reactions, utilizing SO4 on the one hand 2- The combination of superacid properties and the high specific surface area and certain pore structure of molecular sieves can provide more acidic sites, resulting in good catalytic performance, high conversion rate and high product selectivity, good catalyst reproducibility and reusability.
[0011] According to some embodiments of the present invention, the method for preparing the composite catalyst includes impregnating a molecular sieve in an aqueous sulfuric acid solution and calcining it to obtain the composite catalyst.
[0012] According to some embodiments of the present invention, the concentration of the sulfuric acid aqueous solution is 0.05 mol / L to 3.0 mol / L, preferably 0.2 mol / L to 2.0 mol / L.
[0013] According to some embodiments of the present invention, the impregnation conditions include: an impregnation temperature of 20°C to 40°C, and an impregnation time of 1 hour to 16 hours, preferably 3 hours to 12 hours; preferably, the impregnation is performed simultaneously with stirring. In this invention, there is no particular limitation on the stirring rate.
[0014] According to some embodiments of the present invention, the calcination conditions include: a calcination temperature of 300℃~650℃, preferably 400℃~600℃, and a calcination time of 1h~10h, preferably 3h~8h.
[0015] According to some embodiments of the present invention, the drying step is included before the roasting; preferably, the drying conditions include: a drying temperature of 60℃~140℃, more preferably 80℃~120℃, and a drying time of 6h~24h, more preferably 8h~16h.
[0016] According to some embodiments of the present invention, the ratio of the molecular sieve to the sulfuric acid aqueous solution is 1 g: (3-20) mL.
[0017] According to some embodiments of the present invention, the inert atmosphere is selected from at least one of nitrogen, argon, and helium.
[0018] According to some embodiments of the present invention, the naphthalene source is selected from at least one of naphthalene and 2-isopropylnaphthalene.
[0019] According to some embodiments of the present invention, the alkylating agent is selected from propylene.
[0020] According to some embodiments of the present invention, the molar ratio of the naphthalene source to the alkylating agent is 1:1 to 1:6, preferably 1:1 to 1:5.
[0021] According to some embodiments of the present invention, the mass of the composite catalyst is 0.2% to 20% of the mass of the naphthalene source, preferably 0.5% to 12%.
[0022] According to some embodiments of the present invention, the reaction conditions include: a reaction temperature of 150°C to 300°C, preferably 170°C to 270°C; a reaction pressure of 0.5 MPa to 5 MPa, preferably 1 MPa to 3 MPa; and a reaction time of 1 h to 10 h, preferably 3 h to 8 h.
[0023] A second aspect of the present invention provides a heat-conducting oil comprising isopropylnaphthalene synthesized by the synthesis method provided in the first aspect above; preferably, the isopropylnaphthalene has a kinematic viscosity of 2.1 mm at 100°C. 2 / s~2.8mm 2 / s, pour point is -45℃~-40℃.
[0024] Beneficial effects:
[0025] (1) The preparation method of the composite catalyst of the present invention is simple, low in cost, and has potential economic benefits.
[0026] (2) This invention uses SO4 2- Loaded on a molecular sieve support, on the one hand, SO4 is utilized 2- The combination of the properties of superacids and the high specific surface area and certain pore structure of molecular sieves can provide more acidic sites. The resulting composite catalyst exhibits high reaction conversion rate and selectivity for diisopropylnaphthalene in the isopropylation reaction of naphthalene and propylene.
[0027] (3) The isopropyl naphthalene heat transfer oil prepared by the present invention has the characteristics of low viscosity, low pour point and good thermal stability, and can operate at a temperature of 320-330℃ for a long time, and has a very good application prospect. Detailed Implementation
[0028] The present invention will be further described below with reference to embodiments. However, the present invention is not limited to these embodiments.
[0029] Unless otherwise specified, all raw materials used in the following embodiments and comparative examples of the present invention are commercially available.
[0030] In the examples and comparative examples, the analytical methods and the calculations of conversion rate and selectivity are as follows:
[0031] Qualitative and quantitative analysis of the products was performed offline using a Shimadzu GC-2030 gas chromatograph, with separation using an HP-INNOWAX column and detection using a flame ionization detector.
[0032] Conversion rate of naphthalene = (number of moles of naphthalene converted / total number of moles of naphthalene) * 100%;
[0033] DIPN selectivity = (number of moles of DIPN in the product / total number of moles of the product) * 100%;
[0034] Unless otherwise specified, all ion ratios in the embodiments and comparative examples are molar ratios.
[0035] In the various examples and comparative examples, the reaction of naphthalene and propylene can be carried out in a fixed-bed reactor, a batch reactor, or a slurry-bed reactor, and in a continuous or batch reaction process.
[0036] In the examples and comparative examples:
[0037] Naphthalene was purchased from Sinopharm Reagent, with a purity of ≥98.0%, CAS No.: 91-20-3;
[0038] The propylene comes from Sinopec Maoming Branch, with a purity of ≥98.0%.
[0039] ZSM-5 molecular sieve, MCM-22 molecular sieve, Y molecular sieve, and β molecular sieve were all purchased from Zhuoran Environmental Protection Technology Co., Ltd.
[0040] TiO2 was purchased from Sinopharm Reagent, CAS No.: 13463-67-7.
[0041] In this embodiment of the invention, the composite catalyst contains SO4 2- The mass percentage was determined by XRF elemental analysis.
[0042] Example 1
[0043] This embodiment is used to illustrate the composite catalyst, its preparation method, and its application according to the present invention.
[0044] The composite catalyst is prepared as follows:
[0045] Prepare a 0.75 mol / L H2SO4 aqueous solution. Add ZSM-5 molecular sieve to a certain amount of the 0.75 mol / L H2SO4 aqueous solution at a solid-liquid ratio of 1 g: 10 mL. Stir at 40°C for 8 hours, then filter to separate the solids. Dry at 90°C for 16 hours and calcine at 500°C for 5 hours to obtain SO4. 2- / ZSM-5 molecular sieve composite catalyst. Among them, SO4 2- In the ZSM-5 molecular sieve composite catalyst, SO4 2- The mass percentage is 4%.
[0046] This embodiment further provides a method for synthesizing isopropyl naphthalene.
[0047] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 2g of catalyst and 80g of naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor to a pressure of 0.3MPa. The reactor was heated to 150℃, and 78.8g of gaseous propylene was introduced. The reaction temperature was controlled at 250℃, the reaction pressure at 2MPa, and the reaction time at 4 hours. The catalyst was removed by filtration to obtain the filtrate. Naphthalene and monoisopropylnaphthalene were separated by distillation to obtain isopropylnaphthalene heat transfer oil.
[0048] The kinematic viscosity of the aforementioned isopropyl naphthalene heat transfer oil at 100°C is 2.7 mm. 2 The reaction rate was 1 / s, and the pour point was -42℃. The naphthalene conversion and product selectivity in the above reaction are shown in Table 1. The results of catalyst reuse are shown in Table 2.
[0049] Example 2
[0050] This embodiment is used to illustrate the composite catalyst, its preparation method, and its application according to the present invention.
[0051] The composite catalyst is prepared as follows:
[0052] Prepare a 1.0 mol / L H2SO4 aqueous solution. Add MCM-22 molecular sieve to a certain amount of the 1.0 mol / L H2SO4 aqueous solution at a solid-liquid ratio of 1 g: 12 mL. Stir at 35°C for 8 hours, then filter to separate the contents. Dry at 80°C for 12 hours and calcine at 550°C for 5 hours to obtain SO4. 2- / MCM-22 molecular sieve composite catalyst. Among them, SO4 2- In the MCM-22 molecular sieve composite catalyst, SO4 2- The mass percentage is 6%.
[0053] This embodiment further provides a method for synthesizing isopropyl naphthalene.
[0054] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 4.8 g of catalyst and 80 g of naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor to a pressure of 0.3 MPa. The reactor was heated to 150°C, and 78.8 g of gaseous propylene was introduced. The reaction temperature was controlled at 210°C, the reaction pressure at 1.5 MPa, and the reaction time at 5 hours. The catalyst was removed by filtration, and the filtrate was then separated from the naphthalene and monoisopropylnaphthalene by distillation to obtain isopropylnaphthalene heat transfer oil.
[0055] The kinematic viscosity of the aforementioned isopropyl naphthalene heat transfer oil at 100℃ is 2.6 mm. 2 / s, pour point -43℃. The naphthalene conversion rate and product selectivity in the above reaction are shown in Table 1. The physicochemical properties of isopropylnaphthalene heat transfer oil are shown in Table 3.
[0056] Example 3
[0057] This embodiment is used to illustrate the composite catalyst, its preparation method, and its application according to the present invention.
[0058] The composite catalyst is prepared as follows:
[0059] Prepare a 0.75 mol / L H₂SO₄ aqueous solution. Add Y molecular sieve to a certain amount of the 0.75 mol / L H₂SO₄ aqueous solution at a solid-liquid ratio of 1 g: 15 mL. Stir at 30°C for 12 hours, then filter to separate the contents. Dry at 100°C for 12 hours and calcine at 570°C for 5 hours to obtain SO₄. 2- / Y molecular sieve composite catalyst. Among them, SO4 2- In the / Y molecular sieve composite catalyst, SO4 2- The mass percentage is 5%.
[0060] This embodiment further provides a method for synthesizing isopropyl naphthalene.
[0061] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 4.25 g of catalyst and 85 g of solid naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor to a pressure of 0.3 MPa. The reactor was heated to 150°C, and 70 g of gaseous propylene was introduced. The reaction temperature was controlled at 250°C, the reaction pressure at 2.5 MPa, and the reaction time at 5 hours. The catalyst was removed by filtration, and the filtrate was then separated from the naphthalene and monoisopropylnaphthalene by distillation to obtain isopropylnaphthalene heat transfer oil.
[0062] The kinematic viscosity of the aforementioned isopropyl naphthalene heat transfer oil at 100℃ is 2.2 mm. 2 The reaction rate was 1 / s, and the pour point was -45℃. The naphthalene conversion and product selectivity in the above reaction are shown in Table 1.
[0063] Example 4
[0064] This embodiment is used to illustrate the composite catalyst, its preparation method, and its application according to the present invention.
[0065] The composite catalyst is prepared as follows:
[0066] Prepare a 0.75 mol / L H₂SO₄ aqueous solution. Add Y molecular sieve to a certain amount of the 0.75 mol / L H₂SO₄ aqueous solution at a solid-liquid ratio of 1 g: 20 mL. Stir at 30°C for 12 hours, then filter to separate the contents. Dry at 100°C for 12 hours and calcine at 550°C for 5 hours to obtain SO₄. 2- / Y molecular sieve composite catalyst. Among them, SO4 2- In the / Y molecular sieve composite catalyst, SO4 2- The mass percentage is 5%.
[0067] This embodiment further provides a method for synthesizing isopropyl naphthalene.
[0068] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 4.25 g of catalyst and 85 g of naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor to a pressure of 0.3 MPa. The reactor was heated to 150°C, and 55.8 g of gaseous propylene was introduced. The reaction temperature was controlled at 250°C, the reaction pressure at 2.5 MPa, and the reaction time at 5 hours. The catalyst was removed by filtration, and the filtrate was then separated from the naphthalene and monoisopropylnaphthalene by distillation to obtain isopropylnaphthalene heat transfer oil.
[0069] The kinematic viscosity of the aforementioned isopropyl naphthalene heat transfer oil at 100℃ is 2.2 mm. 2 The reaction rate was 1 / s, and the pour point was -45℃. The naphthalene conversion and product selectivity in the above reaction are shown in Table 1.
[0070] Example 5
[0071] This embodiment is used to illustrate the composite catalyst, its preparation method, and its application according to the present invention.
[0072] The composite catalyst is prepared as follows:
[0073] Prepare a 0.5 mol / L H₂SO₄ aqueous solution. Add MCM-22 molecular sieve to a certain amount of the 0.5 mol / L H₂SO₄ aqueous solution at a solid-liquid ratio of 1 g: 12 mL. Stir at 35°C for 8 hours, then filter to separate the solids. Dry at 80°C for 12 hours and calcine at 550°C for 5 hours to obtain SO₄²⁻. 2- / MCM-22 molecular sieve composite catalyst. Among them, SO4 2- In the MCM-22 molecular sieve composite catalyst, SO4 2- The mass percentage is 3%.
[0074] This embodiment further provides a method for synthesizing isopropyl naphthalene.
[0075] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 4.8 g of catalyst and 80 g of naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor to a pressure of 0.3 MPa. The reactor was heated to 150°C, and 78.8 g of gaseous propylene was introduced. The reaction temperature was controlled at 210°C, the reaction pressure at 1.5 MPa, and the reaction time at 5 hours. The catalyst was removed by filtration, and the filtrate was then separated from the naphthalene and monoisopropylnaphthalene by distillation to obtain isopropylnaphthalene heat transfer oil.
[0076] The kinematic viscosity of the above-mentioned isopropyl naphthalene heat transfer oil at 100℃ is 2.5 mm. 2 The reaction rate was 1 / s, and the pour point was -43℃. The naphthalene conversion and product selectivity in the above reaction are shown in Table 1.
[0077] Example 6
[0078] This embodiment is used to illustrate the composite catalyst, its preparation method, and its application according to the present invention.
[0079] The composite catalyst is prepared as follows:
[0080] Prepare a 1.5 mol / L H₂SO₄ aqueous solution. Add MCM-22 molecular sieve to a certain amount of the 1.5 mol / L H₂SO₄ aqueous solution at a solid-liquid ratio of 1 g: 12 mL. Stir at 35°C for 8 hours, then filter to separate the contents. Dry at 80°C for 12 hours and calcine at 550°C for 5 hours to obtain SO₄²⁻. 2- / MCM-22 molecular sieve composite catalyst. Among them, SO4 2-In the MCM-22 molecular sieve composite catalyst, SO4 2- The mass percentage is 10%.
[0081] This embodiment further provides a method for synthesizing isopropyl naphthalene.
[0082] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 4.8 g of catalyst and 80 g of naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor to a pressure of 0.3 MPa. The reactor was heated to 150°C, and 78.8 g of gaseous propylene was introduced. The reaction temperature was controlled at 210°C, the reaction pressure at 1.5 MPa, and the reaction time at 5 hours. The catalyst was removed by filtration, and the filtrate was then separated from the naphthalene and monoisopropylnaphthalene by distillation to obtain isopropylnaphthalene heat transfer oil.
[0083] The kinematic viscosity of the aforementioned isopropyl naphthalene heat transfer oil at 100℃ is 2.7 mm. 2 The reaction rate was 1 / s, and the pour point was -42℃. The naphthalene conversion rate and product selectivity in the above reaction are shown in Table 1.
[0084] Example 7
[0085] This embodiment is used to illustrate the composite catalyst, its preparation method, and its application according to the present invention.
[0086] The composite catalyst is prepared as follows:
[0087] Prepare a 0.5 mol / L H₂SO₄ aqueous solution. Add MCM-22 molecular sieve to a certain amount of the 0.5 mol / L H₂SO₄ aqueous solution at a solid-liquid ratio of 1 g: 12 mL. Stir at 35°C for 8 hours, then filter to separate the solids. Dry at 80°C for 12 hours and calcine at 550°C for 5 hours to obtain SO₄²⁻. 2- / MCM-22 molecular sieve composite catalyst. Among them, SO4 2- In the MCM-22 molecular sieve composite catalyst, SO4 2- The mass percentage is 2%.
[0088] This embodiment further provides a method for synthesizing isopropyl naphthalene.
[0089] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 4.8 g of catalyst and 80 g of naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor to a pressure of 0.3 MPa. The reactor was heated to 150°C, and 78.8 g of gaseous propylene was introduced. The reaction temperature was controlled at 210°C, the reaction pressure at 1.5 MPa, and the reaction time at 5 hours. The catalyst was removed by filtration, and the filtrate was then separated from the naphthalene and monoisopropylnaphthalene by distillation to obtain isopropylnaphthalene heat transfer oil.
[0090] The kinematic viscosity of the aforementioned isopropyl naphthalene heat transfer oil at 100℃ is 2.3 mm. 2 The reaction rate was 1 / s, and the pour point was -44℃. The naphthalene conversion and product selectivity in the above reaction are shown in Table 1.
[0091] Example 8
[0092] This embodiment is used to illustrate the composite catalyst, its preparation method, and its application according to the present invention.
[0093] The composite catalyst is prepared as follows:
[0094] Prepare a 1.75 mol / L H2SO4 aqueous solution. Add MCM-22 molecular sieve to a certain amount of the 1.75 mol / L H2SO4 aqueous solution at a solid-liquid ratio of 1 g: 12 mL. Stir at 35°C for 8 hours, then filter to separate the contents. Dry at 80°C for 12 hours and calcine at 550°C for 5 hours to obtain SO4. 2- / MCM-22 molecular sieve composite catalyst. Among them, SO4 2- In the MCM-22 molecular sieve composite catalyst, SO4 2- The mass percentage is 11%.
[0095] This embodiment further provides a method for synthesizing isopropyl naphthalene.
[0096] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 4.8 g of catalyst and 80 g of naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor to a pressure of 0.3 MPa. The reactor was heated to 150°C, and 78.8 g of gaseous propylene was introduced. The reaction temperature was controlled at 210°C, the reaction pressure at 1.5 MPa, and the reaction time at 5 hours. The catalyst was removed by filtration, and the filtrate was then separated from the naphthalene and monoisopropylnaphthalene by distillation to obtain isopropylnaphthalene heat transfer oil.
[0097] The kinematic viscosity of the aforementioned isopropyl naphthalene heat transfer oil at 100℃ is 2.4 mm. 2 The reaction rate was 1 / s, and the pour point was -44℃. The naphthalene conversion and product selectivity in the above reaction are shown in Table 1.
[0098] Comparative Example 1
[0099] This comparative example is used to illustrate the composite catalyst described in this invention, its preparation method, and its application.
[0100] The composite catalyst is prepared as follows:
[0101] Prepare a 0.75 mol / L H₂SO₄ aqueous solution. Add TiO₂ to a certain amount of the 0.75 mol / L H₂SO₄ aqueous solution at a solid-liquid ratio of 1 g: 15 mL. Stir at 30°C for 12 hours, then filter to separate the contents. Dry at 100°C for 12 hours and calcine at 570°C for 5 hours to obtain SO₄²⁻. 2- / TiO2 composite catalyst. Among them, SO4 2- In the TiO2 molecular sieve composite catalyst, SO4 2- The mass percentage is 5%.
[0102] This comparative example further provides a method for synthesizing isopropyl naphthalene.
[0103] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 4.25 g of catalyst and 85 g of solid naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor until the pressure reached 0.3 MPa. The reactor was heated to 150°C, and 70 g of gaseous propylene was introduced. The reaction temperature was controlled at 250°C, the reaction pressure at 2.5 MPa, and the reaction time at 5 hours.
[0104] The naphthalene conversion rate and product selectivity in the above reactions are shown in Table 1.
[0105] Comparative Example 2
[0106] This comparative example is used to illustrate the composite catalyst described in this invention, its preparation method, and its application.
[0107] The composite catalyst is prepared as follows:
[0108] Prepare a 1.0 mol / L H2SO4 aqueous solution. Add TiO2 to a certain amount of the 1.0 mol / L H2SO4 aqueous solution at a solid-liquid ratio of 1 g: 12 mL. Stir at 35°C for 6 hours, then filter to separate the contents. Dry at 80°C for 12 hours and calcine at 550°C for 5 hours to obtain SO4. 2- / TiO2 composite catalyst. Among them, SO4 2- In the / TiO2 composite catalyst, SO4 2- The mass percentage is 6%.
[0109] This comparative example further provides a method for synthesizing isopropyl naphthalene.
[0110] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 4.8 g of catalyst and 80 g of naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor until the pressure reached 0.3 MPa. After heating to 150°C, 78.8 g of gaseous propylene was introduced. The reaction temperature was controlled at 210°C, the reaction pressure at 1.5 MPa, and the reaction time at 5 hours.
[0111] The naphthalene conversion rate and product selectivity in the above reactions are shown in Table 1.
[0112] Comparative Example 3
[0113] This comparative example is used to illustrate the composite catalyst described in this invention, its preparation method, and its application.
[0114] The catalyst is prepared as follows:
[0115] ZSM-5 catalyst can be obtained by calcining ZSM-5 molecular sieve at 500℃ for 5 hours.
[0116] This comparative example further provides a method for synthesizing isopropyl naphthalene.
[0117] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 2g of catalyst and 80g of naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor until the pressure reached 0.3MPa. After heating to 150℃, 78.8g of gaseous propylene was introduced. The reaction temperature was controlled at 250℃, the reaction pressure at 2MPa, and the reaction time at 4 hours.
[0118] The naphthalene conversion rate and product selectivity in the above reactions are shown in Table 1.
[0119] Comparative Example 4
[0120] This comparative example is used to illustrate the composite catalyst described in this invention, its preparation method, and its application.
[0121] The catalyst is prepared as follows:
[0122] The Y catalyst can be obtained by calcining the Y molecular sieve at 570℃ for 5 hours.
[0123] This comparative example further provides a method for synthesizing isopropyl naphthalene.
[0124] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 4.25 g of catalyst and 85 g of solid naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor until the pressure reached 0.3 MPa. The reactor was heated to 150°C, and 70 g of gaseous propylene was introduced. The reaction temperature was controlled at 250°C, the reaction pressure at 2.5 MPa, and the reaction time at 5 hours.
[0125] The naphthalene conversion rate and product selectivity in the above reactions are shown in Table 1.
[0126] Comparative Example 5
[0127] This comparative example is used to illustrate the composite catalyst described in this invention, its preparation method, and its application.
[0128] The catalyst is prepared as follows:
[0129] Prepare a 0.75 mol / L H₂SO₄ aqueous solution. Add β-molecular sieve to a certain amount of the 0.75 mol / L H₂SO₄ aqueous solution at a solid-liquid ratio of 1 g: 10 mL. Stir at 40 °C for 8 hours, then filter to separate the solids. Dry at 90 °C for 16 hours and calcine at 500 °C for 5 hours to obtain SO₄. 2- / β molecular sieve composite catalyst. Among them, SO4 2- In the β-zeolite composite catalyst, SO4 2- The mass percentage is 4%.
[0130] This comparative example further provides a method for synthesizing isopropyl naphthalene.
[0131] The catalyst prepared above was used to evaluate the isopropylation reaction of naphthalene and propylene in a high-pressure reactor. Specifically, 2g of catalyst and 80g of naphthalene were placed in the reactor, sealed, and purged with nitrogen. Nitrogen was then introduced into the reactor until the pressure reached 0.3MPa. After heating to 150℃, 78.8g of gaseous propylene was introduced. The reaction temperature was controlled at 250℃, the reaction pressure at 2MPa, and the reaction time at 4 hours.
[0132] The naphthalene conversion rate and product selectivity in the above reactions are shown in Table 1.
[0133] Table 1. Statistical analysis of naphthalene and product selectivity in Examples 1-8 and Comparative Examples 1-4
[0134]
[0135]
[0136] As shown in Table 1, in the synthesis methods for preparing diisopropylnaphthalene by isopropylation reaction of naphthalene and propylene in various embodiments of the present invention, the composite catalyst prepared in the present invention can achieve high naphthalene conversion rate and diisopropylnaphthalene selectivity, and the naphthalene conversion rate can reach more than 98%.
[0137] Table 2. Performance evaluation of the reusability of the composite catalyst prepared in Example 1.
[0138]
[0139] Table 3. Physicochemical properties of the isopropylnaphthalene heat transfer oil synthesized in Example 2
[0140]
[0141]
[0142] As shown in Table 3, the isopropylnaphthalene heat transfer oil synthesized using the composite catalyst prepared in Example 2 of this invention has a kinematic viscosity of 2.6 mm at 100°C. 2 The closed-cup flash point is 153℃, indicating that the isopropyl naphthalene heat transfer oil has high safety indicators for storage, transportation, and operation. Secondly, the pour point of the isopropyl naphthalene heat transfer oil is -43℃, indicating that the isopropyl naphthalene heat transfer oil has good low-temperature fluidity, which is beneficial for use in low-temperature environments. Furthermore, the thermal stability test of the isopropyl naphthalene heat transfer oil at 320℃ for 720 hours showed that the deterioration rate of the sample was ≤1.8%, demonstrating excellent thermal stability.
[0143] 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 synthesizing isopropylnaphthalene, characterized in that, This includes the reaction of a naphthalene source and an alkylating agent under an inert atmosphere and in the presence of a composite catalyst to obtain isopropylnaphthalene; The composite catalyst comprises a molecular sieve and SO4 supported on the molecular sieve. 2- Based on the mass of the composite catalyst being 100%, the SO4 2- The mass fraction is 2% to 11%.
2. The synthesis method according to claim 1, characterized in that, The molecular sieve is selected from at least one of Y molecular sieve, ZSM-5 molecular sieve, and MCM-22 molecular sieve; And / or, based on the mass of the composite catalyst being 100%, the SO4 2- The mass fraction is 3% to 10%.
3. The synthesis method according to claim 1 or 2, characterized in that, The method for preparing the composite catalyst includes impregnating a molecular sieve in an aqueous sulfuric acid solution and calcining it to obtain the composite catalyst.
4. The synthesis method according to claim 3, characterized in that, The concentration of the sulfuric acid aqueous solution is 0.05 mol / L to 3.0 mol / L, preferably 0.2 mol / L to 2.0 mol / L.
5. The synthesis method according to claim 3, characterized in that, The impregnation conditions include: an impregnation temperature of 20℃~40℃, an impregnation time of 1h~16h, preferably 3h~12h; preferably, the impregnation is carried out simultaneously with stirring.
6. The synthesis method according to any one of claims 3-5, characterized in that, The calcination conditions include: a calcination temperature of 300℃~650℃, preferably 400℃~600℃, and a calcination time of 1h~10h, preferably 3h~8h; And / or, the roasting process includes a drying step; preferably, the drying conditions include: a drying temperature of 60℃~140℃, more preferably 80℃~120℃, and a drying time of 6h~24h, more preferably 8h~16h.
7. The synthesis method according to any one of claims 3-6, characterized in that, The ratio of the molecular sieve to the sulfuric acid aqueous solution is 1g:(3~20)mL.
8. The synthesis method according to claim 1 or 2, characterized in that, The inert atmosphere is selected from at least one of nitrogen, argon, and helium; And / or, the naphthalene source is selected from at least one of naphthalene and 2-isopropylnaphthalene; And / or, the alkylating agent is selected from propylene; And / or, the molar ratio of the naphthalene source to the alkylating agent is 1:1 to 1:6, preferably 1:1 to 1:5; And / or, the mass of the composite catalyst is 0.2% to 20% of the mass of the naphthalene source, preferably 0.5% to 12%.
9. The synthesis method according to claim 1 or 2, characterized in that, The reaction conditions include: a reaction temperature of 150℃~300℃, preferably 170℃~270℃; a reaction pressure of 0.5MPa~5MPa, preferably 1MPa~3MPa; and a reaction time of 1h~10h, preferably 3h~8h.
10. A heat transfer oil, characterized in that, The heat transfer oil comprises isopropylnaphthalene synthesized by the synthesis method according to any one of claims 1-9; preferably, the kinematic viscosity of the isopropylnaphthalene at 100°C is 2.1 mm. 2 / s~2.8mm 2 / s, pour point is -45℃~-40℃.