Preparation method of alkyl naphthalene and used modified ionic liquid catalyst

Abstract

The invention relates to a preparation method of alkyl naphthalene and a modified ionic liquid catalyst used in the preparation method. The modified ionic liquid catalyst is obtained by modifying ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2 with carbon disulfide. The preparation method of the alkyl naphthalene comprises the following steps: enabling naphthalene, cyclopentene and alpha-olefin to react under the action of the modified ionic liquid catalyst in the claim 1, and then performing post-treatment to obtain an alkyl naphthalene product. The carbon disulfide is used for modifying the ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2, the Lewis acidity of the modified ionic liquid is reduced, and when the modified ionic liquid is used for alkylation reaction of naphthalene, cyclopentene and alpha-olefin, side reactions such as disproportionation can be reduced, and the conversion rate of naphthalene is increased. In addition, the modified ionic liquid catalyst is easier to separate from a reaction mixture, and purification of a target product is facilitated.

Description

Technical Field

[0001] The invention belongs to the field of alkylnaphthalene synthesis, and in particular relates to a modified ionic liquid catalyst and a method for preparing alkylnaphthalene by using the modified ionic liquid catalyst. Background Art

[0002] As early as the 1930s, the United States first added ANs to engine oil for use as synthetic oil, but large-scale production and application did not begin until long after the war. In the 1990s, ExxonMobil first used ANs in lubricant formulations and launched the famous Mobil 1. King Industries in the United States produces ANs products with different molecular weights and structures. Asia started research on ANs relatively late, and only Shanghai NACO Company synthesized commercial products.

[0003] As an efficient blending component of high-grade base oil, alkyl naphthalene base oil can significantly improve the high thermal stability of oil products, the solubility and effectiveness of additives, greatly reduce the amount of additives, extend the service life of oil products, and meet the requirements of high temperature and high heat conditions. Currently developed alkyl naphthalene lubricant products have a single structure, and their molecular structure is mostly composed of a single long-chain alkyl naphthalene. The physicochemical properties and uses of alkyl naphthalene chemicals depend on the molecular structure and number of side chains, and the lubrication performance of the products is limited. Therefore, the synthesis of a series of polyalkyl naphthalenes with different numbers, lengths and structures is of great significance to enrich the types and uses of alkyl naphthalene lubricants.

[0004] CN 108129252 B discloses a method for preparing cycloalkyl and its application, wherein immobilized AlCl3 is used as a catalyst, naphthalene, medium-long chain α-olefins, and cycloolefins are used as raw materials, and an alkylation reaction of naphthalene is carried out. The synthesized cycloalkyl naphthalene base oil can be used for liquid lubrication under harsh conditions (high speed, high and low temperature, high vacuum, etc.) of space machinery. However, the catalyst activity in the method needs to be improved, and the conversion rate of naphthalene is low.

[0005] "Highly Selective Synthesis of Polyalkylated Naphthalenes Catalyzedby Ionic Liquids and Their Tribological Properties as Lubricant Base Oil" discloses the efficient synthesis of polyalkylated naphthalenes by alkylation of naphthalene catalyzed by Et3NHCl-AlCl3 ionic liquid. This paper systematically studies the effects of the structure and composition of ionic liquids on the alkylation of naphthalene. Taking cycloalkyl lubricating oil as a reference, the basic physicochemical properties and tribological properties of polyalkylated naphthalenes with different side chains as lubricating oils were studied, revealing the structure-activity relationship of alkylated naphthalene as a lubricating base oil. Et3NHCl-AlCl3 ionic liquids show high selectivity and conversion rate for polyalkylated naphthalene products with three or four side chains. However, the viscosity of the alkylated naphthalene base oil synthesized using Et3NHCl-AlCl3 ionic liquid catalyst is not high.

[0006] Therefore, further research on the preparation method of alkyl naphthalene is still needed in this field. Summary of the invention

[0007] The main purpose of the present invention is to provide a method for preparing alkyl naphthalene and a modified ionic liquid catalyst used therein, so as to overcome the problem that the catalytic activity, naphthalene conversion rate and viscosity of the prepared alkyl naphthalene of the catalyst used in the prior art cannot be taken into account.

[0008] In order to achieve the above-mentioned object, the present invention provides a modified ionic liquid catalyst, which is used to catalyze the reaction of naphthalene, cyclopentene and α-olefin to produce alkylnaphthalene products. The modified ionic liquid catalyst is obtained by modifying the ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2 with carbon disulfide.

[0009] The modified ionic liquid catalyst of the present invention, wherein the amount of carbon disulfide used is 500-1500 μg / g of the mass of the modified ionic liquid.

[0010] The modified ionic liquid catalyst of the present invention, wherein the step of modifying the carbon disulfide ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2 is: mixing at least one of the ionic liquids Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2 with carbon disulfide, stirring, to obtain the modified ionic liquid catalyst.

[0011] In order to achieve the above object, the present invention also provides a method for preparing alkyl naphthalene, comprising the following steps:

[0012] Naphthalene, cyclopentene and α-olefin are reacted under the action of the modified ionic liquid catalyst according to claim 1, and then post-treated to obtain an alkylnaphthalene product.

[0013] The preparation method of alkyl naphthalene of the present invention, wherein the post-treatment comprises: adding clay and calcium hydroxide to the reaction mixture, stirring and filtering to remove the modified ionic liquid catalyst, and then separating the filtrate to obtain the alkyl naphthalene product.

[0014] The method for preparing alkyl naphthalene of the present invention comprises the following steps: the molar ratio of naphthalene to α-olefin is 1:1-1:4, the molar ratio of naphthalene to cyclopentene is 1:1-1:4; the molar ratio of the modified ionic liquid catalyst to naphthalene is 0.1-0.2, and the molar number of the modified ionic liquid catalyst is calculated based on the amount of AlCl3, FeCl3 and ZnCl2 substances.

[0015] In the method for preparing alkyl naphthalene of the present invention, the α-olefin is at least one of 1-octene, 1-nonene, 1-decene, 1-dodecene and 1-tetradecene.

[0016] In the method for preparing alkyl naphthalene of the present invention, the reaction of naphthalene, cyclopentene and alpha-olefin is carried out in an organic solvent, the organic solvent is an organic hydrocarbon; and the molar ratio of naphthalene to the organic solvent is 1:4 to 1:8.

[0017] In the method for preparing alkyl naphthalene of the present invention, the reaction temperature of naphthalene, cyclopentene and alpha-olefin is 20-100° C., and the reaction time is 1-4 hours.

[0018] In the method for preparing alkyl naphthalene of the present invention, the filtrate is separated by vacuum distillation.

[0019] Beneficial effects of the present invention:

[0020] (1) The present invention uses carbon disulfide to modify the ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2. The Lewis acidity of the modified ionic liquid decreases. When used in the alkylation reaction of naphthalene, cyclopentene and α-olefin, the occurrence of side reactions such as disproportionation can be reduced, and the conversion rate of naphthalene can be improved. In addition, the modified ionic liquid catalyst is easier to separate from the reaction mixture, which is beneficial to the purification of the target product.

[0021] (2) The alkylnaphthalene synthesized by the present invention has the performance advantages of α-olefins, five-membered cycloalkyls, and alkylnaphthalene compounds, has high viscosity and viscosity index, and has a high yield of the product alkylnaphthalene. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Et3NHCl-AlCl3 ionic liquid before and after carbon disulfide modification 27 Al NMR spectroscopy. DETAILED DESCRIPTION

[0023] The technical scheme of the present invention is described in detail below. The following implementation modes are implemented on the premise of the technical scheme of the present invention, and a detailed implementation process is given. However, the protection scope of the present invention is not limited to the following implementation modes. The structures or experimental methods of specific conditions are not specified in the following implementation modes, and generally conventional conditions are followed.

[0024] The invention provides a modified ionic liquid catalyst, which is used for catalyzing the reaction of naphthalene, cyclopentene and alpha-olefin to generate alkylnaphthalene. The modified ionic liquid catalyst is obtained by modifying ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2 with carbon disulfide.

[0025] The present invention improves the problems of low catalytic activity and low naphthalene conversion rate when Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2 is used for alkylation reaction of naphthalene, cyclopentene and alpha-olefin by modifying ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2. When the modified ionic liquid catalyst modified by the method of the present invention is used for alkylation reaction of naphthalene, cyclopentene and alpha-olefin, the catalyst has high catalytic efficiency, naphthalene has high conversion rate, and the prepared alkyl naphthalene has high viscosity and viscosity index.

[0026] In one embodiment, the amount of carbon disulfide is 500-1500 μg / g of the mass of the modified ionic liquid. In other words, the amount of carbon disulfide is 500-1500 μg / g of the sum of the mass of carbon disulfide and the ionic liquid to be modified. The present invention does not particularly limit the source of carbon disulfide, for example, it is a commercially available product.

[0027] In one embodiment, the step of modifying the ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2 with carbon disulfide is: mixing at least one of the ionic liquids Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2 with carbon disulfide, stirring, and obtaining a modified ionic liquid catalyst.

[0028] The mixing temperature of the ionic liquid and carbon disulfide is, for example, room temperature, i.e., 20-30° C., which is not particularly limited in the present invention. The obtained modified ionic liquid can be recorded as Et3NHCl-AlCl3-CS2, Et3NHCl-FeCl3-CS2, and Et3NHCl-ZnCl2-CS2.

[0029] The Lewis acid contained in ionic liquids is the main source of their catalytic activity. Figure 1 Et3NHCl-AlCl3 ionic liquid before and after carbon disulfide modification 27 Al NMR spectrum, where (a) is the AlCl3-Et3NHCl ionic liquid before carbon disulfide modification 27 Al NMR spectrum, (b) AlCl3-Et3NHCl ionic liquid modified with carbon disulfide 27 Al NMR spectrum. As shown in the figure, before the ionic liquid is modified with carbon disulfide, the aluminum element in the ionic liquid is mainly in the form of AlCl4 - The chemical shift of the ionic liquid is 103.1ppm. After the ionic liquid is modified with carbon disulfide, a peak with a chemical shift of 99.4ppm appears in the spectrum, and AlCl4 - The peak height of AlCl4 - The content of CS2 decreased, which means that the structure of the ionic liquid has changed. CS2 has complexed with the Lewis acid in the ionic liquid to form a new complex, and a new obvious peak has appeared in the nuclear magnetic resonance spectrum.

[0030] The coordination substances formed by different organic substances have different effects on the steps of hydrogen transfer, isomerization, cracking and disproportionation in the alkylation reaction. The present invention modifies the ionic liquid by carbon disulfide so that carbon disulfide and Lewis acidic substances form a new complex. The formation of the complex is beneficial to the alkylation reaction of naphthalene, cyclopentene and α-olefins, thereby improving the yield and selectivity of the target product.

[0031] The present invention takes Et3NHCl-AlCl3 ionic liquid as an example to illustrate the structural changes of ionic liquids before and after carbon disulfide modification. The structural changes of ionic liquids Et3NHCl-FeCl3 and Et3NHCl-ZnCl2 before and after carbon disulfide modification are similar to those of Et3NHCl-AlCl3 ionic liquid, and will not be repeated here.

[0032] The present invention does not specifically limit the preparation method of the ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2, and a conventional preparation method in the prior art can be used. In one embodiment, the preparation method of the ionic liquid is as follows:

[0033] Place triethylamine hydrochloride (Et3NHCl) in an organic solvent, add anhydrous aluminum chloride, anhydrous ferric chloride or anhydrous zinc chloride, heat and stir to obtain ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2.

[0034] The addition of anhydrous aluminum chloride, anhydrous ferric chloride or anhydrous zinc chloride can be carried out in batches, so that the reaction speed can be controlled to avoid too fast or too slow reaction. The molar ratio of anhydrous aluminum chloride, anhydrous ferric chloride or anhydrous zinc chloride to triethylamine hydrochloride can be 0.5-2:1, and the temperature is raised to 40-80°C for stirring, and the stirring time is 2-3 hours.

[0035] The present invention also provides a method for preparing alkylnaphthalene, using the modified ionic liquid catalyst, comprising the following steps:

[0036] Naphthalene, cyclopentene and α-olefin are reacted under the action of the modified ionic liquid catalyst, and then post-treated to obtain the final alkyl naphthalene product.

[0037] The present invention uses carbon disulfide modified ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2 for alkylation reaction of naphthalene, cyclopentene and alpha-olefin, and the Lewis acidity of the modified ionic liquid is reduced, which can reduce the occurrence of side reactions such as disproportionation and improve the conversion rate of naphthalene. In addition, the alkyl naphthalene product obtained by the method of the present invention has higher viscosity and viscosity index.

[0038] In one embodiment, the post-treatment includes: adding clay and calcium hydroxide to the reaction mixture, stirring and filtering to remove the modified ionic liquid catalyst, and then separating the filtrate to obtain the alkyl naphthalene base oil. The filtrate is separated by vacuum distillation.

[0039] In one embodiment, the molar ratio of naphthalene to α-olefin is 1:1 to 1:4, the molar ratio of naphthalene to cyclopentene is 1:1 to 1:4, preferably 1:2, and the molar ratio of the modified ionic liquid catalyst to naphthalene is 0.1 to 0.2, wherein the molar number of the modified ionic liquid catalyst is based on the amount of AlCl3, FeCl3, and ZnCl2 substances. In the present invention, the carbon number of the α-olefin is, for example, 6 to 20, specifically, it can be at least one of 1-octene, 1-nonene, 1-decene, 1-dodecene, and 1-tetradecene.

[0040] In one embodiment, the reaction of naphthalene, cyclopentene and α-olefin is carried out in an organic solvent, and the organic solvent is an organic hydrocarbon, specifically, n-decane. The molar ratio of naphthalene to the organic solvent is 1:4 to 1:8. In another embodiment, cyclopentene, α-olefin and modified ionic liquid catalyst are first mixed, heated to the reaction temperature for reaction, and then naphthalene and organic solvent are added to continue the reaction.

[0041] In one embodiment, the reaction temperature of naphthalene, cyclopentene and α-olefin is 20 to 100° C., preferably 60 to 80° C., and the reaction time is 1 to 4 hours.

[0042] In the alkyl naphthalene preparation process of the present invention, the conversion rate of naphthalene can reach 100%, and the modified ionic liquid catalyst used has less corrosion to equipment and is environmentally friendly.

[0043] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0044] The raw materials used in the following examples and comparative examples are shown in Table 1.

[0045] Table 1 Source of raw materials

[0046] name Specification Manufacturer Naphthalene 99％ Aladdin Chemical Reagent Co., Ltd. 1-Octene Analytical grade Aladdin Chemical Reagent Co., Ltd. 1-Nonene Analytical grade Aladdin Chemical Reagent Co., Ltd. 1-Decene Analytical grade Aladdin Chemical Reagent Co., Ltd. 1-Dodecene Analytical grade Aladdin Chemical Reagent Co., Ltd. 1-Tetradecene Analytical grade Aladdin Chemical Reagent Co., Ltd. Ionic Liquids self made Cyclopentene 98％ Aladdin Chemical Reagent Co., Ltd. n-Decane 99％ Aladdin Chemical Reagent Co., Ltd. Cyclohexane 99％ Aladdin Chemical Reagent Co., Ltd. Carbon disulfide Analytical grade Aladdin Chemical Reagent Co., Ltd.

[0047] Evaluation and analysis methods: Lubricant base oil pour point analysis, kinematic viscosity analysis

[0048] Embodiment 1:

[0049] The raw materials 1-octene (2 mol), cyclopentene (0.2 mol), and modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 (0.015 mol) were added to a three-necked round-bottom flask, and placed in a 60°C constant temperature oil bath to react for 0.5 h, and then naphthalene (0.1 mol) and n-decane (0.4 mol) were added to continue the reaction for 2 h. After the reaction, white clay and calcium hydroxide were added and filtered to remove the catalyst in the reaction. The product was subjected to reduced pressure distillation to remove the organic solvent and residual naphthalene to obtain the final alkyl naphthalene product. The obtained product was subjected to performance testing, and its performance data are listed in Table 2.

[0050] The preparation method of the modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 is as follows: a certain mass of AlCl3 and Et3NHCl is weighed in a molar ratio of 1:1 and added to a dry single-necked flask, and a certain amount of n-heptane is added as a solvent; the single-necked flask is transferred to a constant temperature magnetic stirrer, and the constant temperature magnetic stirrer is adjusted to slowly heat up to 80°C under continuous stirring, and after reacting for 3 hours, the single-necked flask is transferred to a rotary evaporator, and n-heptane in the reaction mixture is removed by vacuum distillation to obtain Et3NHCl-AlCl3 ionic liquid catalyst. Subsequently, carbon disulfide with a concentration of 1000 μg / g is added to Et3NHCl-AlCl3, and stirred and mixed thoroughly at room temperature to form a modified ionic liquid Et3NHCl-AlCl3-CS2.

[0051] Embodiment 2:

[0052] The raw materials 1-decene (0.3 mol), cyclopentene (0.3 mol), and modified ionic liquid catalyst Et3NHCl-FeCl3-CS2 (0.03 mol) were added to a three-necked round-bottom flask, and placed in a 60°C constant temperature oil bath to react for 0.5 h, and then naphthalene (0.15 mol) and n-decane (0.9 mol) were added to continue the reaction for 1.5 h. After the reaction was completed, white clay and calcium hydroxide were added and filtered to remove the catalyst in the reaction. The product was subjected to reduced pressure distillation to remove the organic solvent and residual naphthalene to obtain the final alkyl naphthalene product. The obtained product was subjected to performance testing, and its performance data are listed in Table 2.

[0053] The preparation method of the modified ionic liquid catalyst Et3NHCl-FeCl3-CS2 is as follows: a certain mass of FeCl3 and Et3NHCl is weighed in a molar ratio of 1:1 and added to a dry single-necked flask, and a certain amount of n-heptane is added as a solvent; the single-necked flask is transferred to a constant temperature magnetic stirrer, and the constant temperature magnetic stirrer is adjusted to slowly heat up to 80°C under continuous stirring, and after reacting for 3 hours, the single-necked flask is transferred to a rotary evaporator, and the n-heptane in the reaction mixture is removed by reduced pressure distillation to obtain Et3NHCl-FeCl3 ionic liquid catalyst. Subsequently, carbon disulfide with a concentration of 500 μg / g is added to Et3NHCl-FeCl3, and stirred and mixed thoroughly at room temperature to form a modified ionic liquid Et3NHCl-FeCl3-CS2.

[0054] Embodiment 3:

[0055] The raw materials 1-nonene (0.4 mol), cyclopentene (0.4 mol), and modified ionic liquid catalyst Et3NHCl-ZnCl2-CS2 (0.03 mol) were added to a three-necked round-bottom flask, and placed in a 60°C constant temperature oil bath for reaction for 1 hour, and then naphthalene (0.2 mol) and n-decane (0.6 mol) were added to continue the reaction for 1 hour. After the reaction, white clay and calcium hydroxide were added and filtered to remove the catalyst in the reaction. The product was subjected to reduced pressure distillation to remove the organic solvent and residual naphthalene to obtain the final alkyl naphthalene product. The obtained product was subjected to performance testing, and its performance is listed in Table 2.

[0056] The preparation method of the modified ionic liquid catalyst Et3NHCl-ZnCl2-CS2 is as follows: a certain mass of ZnCl2 and Et3NHCl is weighed and added into a dry single-necked flask according to a molar ratio of 1:1, and a certain amount of n-heptane is added as a solvent; the single-necked flask is transferred to a constant temperature magnetic stirrer, and the constant temperature magnetic stirrer is adjusted to slowly heat up to 70°C under continuous stirring, and after reacting for 3 hours, the single-necked flask is transferred to a rotary evaporator, and n-heptane in the reaction mixture is removed by vacuum distillation to obtain Et3NHCl-ZnCl2 ionic liquid catalyst. Subsequently, carbon disulfide with a concentration of 1000 μg / g is added to Et3NHCl-ZnCl2, and stirred and mixed thoroughly at room temperature to form a modified ionic liquid Et3NHCl-FeCl3-CS2.

[0057] Embodiment 4:

[0058] The raw materials 1-dodecene (0.6 mol), cyclopentene (0.6 mol), and modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 (0.06 mol) were added to a three-necked round-bottom flask, and placed in a 60°C constant temperature oil bath for reaction for 0.5 h, and then naphthalene (0.3 mol) and n-decane (2.1 mol) were added to continue the reaction for 1.5 h. After the reaction, white clay and calcium hydroxide were added and filtered to remove the catalyst in the reaction. The product was subjected to reduced pressure distillation to remove the organic solvent and residual naphthalene to obtain the final alkyl naphthalene product. The obtained product was subjected to performance testing, and its performance is listed in Table 2.

[0059] The preparation method of the modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 is as follows: a certain mass of AlCl3 and Et3NHCl is weighed in a molar ratio of 1:1 and added to a dry single-necked flask, and a certain amount of n-heptane is added as a solvent; the single-necked flask is transferred to a constant temperature magnetic stirrer, and the constant temperature magnetic stirrer is adjusted to slowly heat up to 80°C under continuous stirring, and after reacting for 3 hours, the single-necked flask is transferred to a rotary evaporator, and n-heptane in the reaction mixture is removed by reduced pressure distillation to obtain Et3NHCl-AlCl3 ionic liquid catalyst. Subsequently, carbon disulfide with a concentration of 1500 μg / g is added to Et3NHCl-AlCl3, and stirred and mixed at room temperature to form a modified ionic liquid Et3NHCl-AlCl3-CS2.

[0060] Embodiment 5:

[0061] The raw materials 1-tetradecene (0.9 mol), cyclopentene (0.6 mol), and modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 (0.03 mol) were added to a three-necked round-bottom flask, and placed in a 70°C constant temperature oil bath to react for 0.5 h, and then naphthalene (0.3 mol) and n-decane (2.4 mol) were added to continue the reaction for 1.5 h. After the reaction was completed, white clay and calcium hydroxide were added and filtered to remove the catalyst in the reaction. The product was subjected to reduced pressure distillation to remove the organic solvent and residual naphthalene to obtain the final alkyl naphthalene product. The obtained product was subjected to performance testing, and its performance is listed in Table 2.

[0062] The preparation method of the modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 is as follows: a certain mass of AlCl3 and Et3NHCl is weighed in a molar ratio of 1:1 and added to a dry single-necked flask, and a certain amount of n-heptane is added as a solvent; the single-necked flask is transferred to a constant temperature magnetic stirrer, and the constant temperature magnetic stirrer is adjusted to slowly heat up to 80°C under continuous stirring, and after reacting for 3 hours, the single-necked flask is transferred to a rotary evaporator, and n-heptane in the reaction mixture is removed by vacuum distillation to obtain Et3NHCl-AlCl3 ionic liquid catalyst. Subsequently, carbon disulfide with a concentration of 1000 μg / g is added to Et3NHCl-AlCl3, and stirred and mixed thoroughly at room temperature to form a modified ionic liquid Et3NHCl-AlCl3-CS2.

[0063] Embodiment 6:

[0064] The raw materials 1-dodecene (0.4 mol), cyclopentene (0.4 mol), and modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 (0.03 mol) were added to a three-necked round-bottom flask, and placed in a 20°C constant temperature oil bath to react for 0.5 h, and then naphthalene (0.2 mol) and n-decane (0.8 mol) were added to continue the reaction for 2 h. After the reaction, white clay and calcium hydroxide were added and filtered to remove the catalyst in the reaction. The product was subjected to reduced pressure distillation to remove the organic solvent and residual naphthalene to obtain the final alkyl naphthalene product. The obtained product was subjected to performance testing, and its performance is listed in Table 2.

[0065] The preparation method of the modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 is as follows: a certain mass of AlCl3 and Et3NHCl is weighed in a molar ratio of 1:1 and added to a dry single-necked flask, and a certain amount of n-heptane is added as a solvent; the single-necked flask is transferred to a constant temperature magnetic stirrer, and the constant temperature magnetic stirrer is adjusted to slowly heat up to 80°C under continuous stirring, and after reacting for 3 hours, the single-necked flask is transferred to a rotary evaporator, and n-heptane in the reaction mixture is removed by vacuum distillation to obtain Et3NHCl-AlCl3 ionic liquid catalyst. Subsequently, carbon disulfide with a concentration of 1000 μg / g is added to Et3NHCl-AlCl3, and stirred and mixed thoroughly at room temperature to form a modified ionic liquid Et3NHCl-AlCl3-CS2.

[0066] Embodiment 7:

[0067] The raw materials 1-tetradecene (0.4 mol), cyclopentene (0.4 mol), and modified ionic liquid catalyst Et3NHCl-FeCl3-CS2 (0.03 mol) were added to a three-necked round-bottom flask, and placed in a 30°C constant temperature oil bath to react for 0.5 h, and then naphthalene (0.2 mol) and n-decane (0.8 mol) were added to continue the reaction for 2.5 h. After the reaction was completed, white clay and calcium hydroxide were added and filtered to remove the catalyst in the reaction. The product was subjected to reduced pressure distillation to remove the organic solvent and residual naphthalene to obtain the final alkyl naphthalene product. The obtained product was subjected to performance testing, and its performance is listed in Table 2.

[0068] The preparation method of the modified ionic liquid catalyst Et3NHCl-FeCl3-CS2 is as follows: a certain mass of FeCl3 and Et3NHCl is weighed in a molar ratio of 1:1 and added to a dry single-necked flask, and a certain amount of n-heptane is added as a solvent; the single-necked flask is transferred to a constant temperature magnetic stirrer, and the constant temperature magnetic stirrer is adjusted to slowly heat up to 80°C under continuous stirring, and after reacting for 3 hours, the single-necked flask is transferred to a rotary evaporator, and the n-heptane in the reaction mixture is removed by reduced pressure distillation to obtain Et3NHCl-FeCl3 ionic liquid catalyst. Subsequently, carbon disulfide with a concentration of 500 μg / g is added to Et3NHCl-FeCl3, and stirred and mixed thoroughly at room temperature to form a modified ionic liquid Et3NHCl-FeCl3-CS2.

[0069] Embodiment 8:

[0070] The raw materials 1-decene (0.6 mol), cyclopentene (0.4 mol), and modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 (0.04 mol) were added to a three-necked round-bottom flask, and placed in a 40°C constant temperature oil bath for reaction for 0.5 h, and then naphthalene (0.2 mol) and n-decane (0.12 mol) were added to continue the reaction for 2 h. After the reaction was completed, white clay and calcium hydroxide were added and filtered to remove the catalyst in the reaction. The product was subjected to reduced pressure distillation to remove the organic solvent and residual naphthalene to obtain the final alkyl naphthalene product. The obtained product was subjected to performance testing, and its performance is listed in Table 2.

[0071] The preparation method of the modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 is as follows: a certain mass of AlCl3 and Et3NHCl is weighed and added into a dry single-necked flask according to a molar ratio of 1:1, and a certain amount of n-heptane is added as a solvent; the single-necked flask is transferred to a constant temperature magnetic stirrer, and the constant temperature magnetic stirrer is adjusted to slowly heat up to 80°C under continuous stirring, and after reacting for 3 hours, the single-necked flask is transferred to a rotary evaporator, and n-heptane in the reaction mixture is removed by vacuum distillation to obtain Et3NHCl-AlCl3 ionic liquid catalyst. Subsequently, carbon disulfide with a concentration of 1000 μg / g is added to Et3NHCl-AlCl3, and stirred and mixed thoroughly at room temperature to form a modified ionic liquid Et3NHCl-AlCl3-CS2.

[0072] Embodiment 9:

[0073] The raw materials 1-dodecene (0.2 mol), cyclopentene (0.4 mol), and modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 (0.02 mol) were added to a three-necked round-bottom flask, and placed in a 50°C constant temperature oil bath to react for 0.5 h, and then naphthalene (0.2 mol) and n-decane (0.1 mol) were added to continue the reaction for 2 h. After the reaction, white clay and calcium hydroxide were added and filtered to remove the catalyst in the reaction. The product was subjected to reduced pressure distillation to remove the organic solvent and residual naphthalene to obtain the final alkyl naphthalene product. The obtained product was subjected to performance testing, and its performance is listed in Table 2.

[0074] The preparation method of the modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 is as follows: a certain mass of AlCl3 and Et3NHCl is weighed in a molar ratio of 1:1 and added to a dry single-necked flask, and a certain amount of n-heptane is added as a solvent; the single-necked flask is transferred to a constant temperature magnetic stirrer, and the constant temperature magnetic stirrer is adjusted to slowly heat up to 80°C under continuous stirring, and after reacting for 3 hours, the single-necked flask is transferred to a rotary evaporator, and n-heptane in the reaction mixture is removed by vacuum distillation to obtain Et3NHCl-AlCl3 ionic liquid catalyst. Subsequently, carbon disulfide with a concentration of 1000 μg / g is added to Et3NHCl-AlCl3, and stirred and mixed thoroughly at room temperature to form a modified ionic liquid Et3NHCl-AlCl3-CS2.

[0075] Embodiment 10:

[0076] The raw materials 1-tetradecene (0.6 mol), cyclopentene (0.4 mol), and modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 (0.02 mol) were added to a three-necked round-bottom flask, and placed in a 90°C constant temperature oil bath for reaction for 0.5 h, and then naphthalene (0.2 mol) and n-decane (0.12 mol) were added to continue the reaction for 2 h. After the reaction, white clay and calcium hydroxide were added and filtered to remove the catalyst in the reaction. The product was subjected to reduced pressure distillation to remove the organic solvent and residual naphthalene to obtain the final alkyl naphthalene product. The obtained product was subjected to performance testing, and its performance is listed in Table 2.

[0077] The preparation method of the modified ionic liquid catalyst Et3NHCl-AlCl3-CS2 is as follows: a certain mass of AlCl3 and Et3NHCl is weighed in a molar ratio of 1:1 and added to a dry single-necked flask, and a certain amount of n-heptane is added as a solvent; the single-necked flask is transferred to a constant temperature magnetic stirrer, and the constant temperature magnetic stirrer is adjusted to slowly heat up to 80°C under continuous stirring, and after reacting for 3 hours, the single-necked flask is transferred to a rotary evaporator, and n-heptane in the reaction mixture is removed by vacuum distillation to obtain Et3NHCl-AlCl3 ionic liquid catalyst. Subsequently, carbon disulfide with a concentration of 1000 μg / g is added to Et3NHCl-AlCl3, and stirred and mixed thoroughly at room temperature to form a modified ionic liquid Et3NHCl-AlCl3-CS2.

[0078] Comparative Example 1

[0079] The raw materials 1-decene (0.6 mol), cyclopentene (0.4 mol), and ionic liquid catalyst Et3NHCl-AlCl3 (0.04 mol) were added to a three-necked round-bottom flask, and placed in a 40°C constant temperature oil bath for reaction for 0.5 h, and then naphthalene (0.2 mol) and n-decane (0.12 mol) were added to continue the reaction for 2 h. After the reaction was completed, white clay and calcium hydroxide were added and filtered to remove the catalyst in the reaction. The product was subjected to reduced pressure distillation to remove the organic solvent and residual naphthalene, and finally the alkyl naphthalene product was obtained. The obtained product was subjected to performance testing, and its performance is listed in Table 2.

[0080] Comparative Example 2

[0081] The raw materials 1-decene (0.mol), cyclopentene (0.4mol), solid acid catalyst SO4 2- / Al2O3 (0.04 mol) was added to a three-necked round-bottom flask, and the flask was placed in a 40°C constant temperature oil bath for reaction for 0.5 h, and then naphthalene (0.2 mol) and n-decane (0.12 mol) were added to continue the reaction for 2 h. After the reaction, white clay and calcium hydroxide were added and filtered to remove the catalyst in the reaction. The product was subjected to reduced pressure distillation to remove the organic solvent and residual naphthalene, and finally the alkyl naphthalene product was obtained. The obtained product was subjected to performance testing, and its performance is listed in Table 2.

[0082] Comparative Example 3 (Preparation of alkyl naphthalene according to CN 109824467 A)

[0083] The ionic liquid catalyst was prepared by using AlCl3, triethylamine hydrochloride and an inert organic solvent. Naphthalene was first added to the ionic liquid, and then 1-octene was slowly dripped into the mixture according to the molar ratio of naphthalene (mol): 1-octene (mol) = 1:8, and ionic liquid (mol): naphthalene (mol) = 1:8. The mixture was stirred and reacted at 60°C in a constant temperature oil bath for 60 minutes. After the reaction, the mixture was cooled to room temperature and separated. The upper liquid product was washed with water to remove a small amount of ionic liquid, and then the inert organic solvent and residual naphthalene were removed by reduced pressure distillation. Then, the remaining liquid was extracted with n-propanol three times until the n-propanol phase was colorless and transparent, and then the n-propanol was completely removed by atmospheric distillation to obtain the final polyalkyl naphthalene product. The properties of the obtained product are listed in Table 2.

[0084] Table 2 Alkyl naphthalene performance table

[0085]

[0086] Compared with the comparative example, the alkyl naphthalene product prepared by the present invention has high viscosity and high viscosity index, and the use of the modified ionic liquid catalyst can make the conversion rate of naphthalene reach 100%.

[0087] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A modified ionic liquid catalyst, characterized in that: The modified ionic liquid catalyst is used for catalyzing the reaction of naphthalene, cyclopentene and alpha-olefin to generate alkylnaphthalene. The modified ionic liquid catalyst is obtained by modifying the ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2 with carbon disulfide.

2. The modified ionic liquid catalyst according to claim 1, characterized in that The amount of carbon disulfide used is 500-1500 μg / g of the mass of the modified ionic liquid.

3. The modified ionic liquid catalyst according to claim 1, characterized in that The step of modifying the ionic liquid Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2 with carbon disulfide is: mixing at least one of the ionic liquids Et3NHCl-AlCl3, Et3NHCl-FeCl3 or Et3NHCl-ZnCl2 with carbon disulfide, stirring, and obtaining the modified ionic liquid catalyst.

4. A method for preparing alkylnaphthalene, characterized in that: The steps include: Naphthalene, cyclopentene and α-olefin are reacted under the action of the modified ionic liquid catalyst according to claim 1, and then post-treated to obtain an alkylnaphthalene product.

5. The method for preparing alkylnaphthalene according to claim 4, characterized in that: The post-treatment comprises: adding clay and calcium hydroxide into the reaction mixture, stirring and filtering to remove the modified ionic liquid catalyst, and then separating the filtrate to obtain alkyl naphthalene.

6. The method for preparing alkylnaphthalene according to claim 4, characterized in that: The molar ratio of naphthalene to α-olefin is 1:1 to 1:4, and the molar ratio of naphthalene to cyclopentene is 1:1 to 1:4; the molar ratio of the modified ionic liquid catalyst to naphthalene is 0.1 to 0.2, and the molar number of the modified ionic liquid catalyst is calculated based on the amount of AlCl3, FeCl3, and ZnCl2 substances.

7. The method for preparing alkylnaphthalene according to claim 4, characterized in that: The α-olefin is at least one of 1-octene, 1-nonene, 1-decene, 1-dodecene and 1-tetradecene.

8. The method for preparing alkylnaphthalene according to claim 4, characterized in that: The reaction of naphthalene, cyclopentene and alpha-olefin is carried out in an organic solvent, which is an organic hydrocarbon; the molar ratio of naphthalene to the organic solvent is 1:4 to 1:

8.

9. The method for preparing alkylnaphthalene according to claim 4, characterized in that: The reaction temperature of naphthalene, cyclopentene and α-olefin is 20-100° C., and the reaction time is 1-4 hours.

10. The method for preparing alkylnaphthalene according to claim 4, characterized in that: The filtrate is separated by distillation under reduced pressure.

Images