Compositions, deep eutectic solvents, methods of making and using the same, and methods of extracting aromatics from petroleum distillates

Abstract

The present application relates to the field of petroleum component separation, discloses a kind of composition, eutectic solvent and its preparation method and application, the method for extracting and separating aromatic hydrocarbon in petroleum fraction.A kind of composition, the composition includes 1-ethyl pyridine chloro salt and acetylenic acid;Wherein, the molar ratio of 1-ethyl pyridine chloro salt and acetylenic acid is 0.5-5:1.The eutectic solvent prepared by the specific composition disclosed in the present application is used to extract and separate aromatic hydrocarbon in petroleum fraction, and there is basically no solvent residue in the raffinate obtained, the subsequent aromatic hydrocarbon separation method is simple, the extraction effect is obviously improved;And compared with the existing commonly used extraction solvent, it has higher aromatic hydrocarbon selectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of petroleum component separation, in particular to a composition, a eutectic solvent and a preparation method and application thereof, and a method for extracting and separating aromatic hydrocarbons in petroleum distillates. BACKGROUND

[0002] At present, China's petrochemical industry is in a period of transformation and development, and the demand for high-quality fuels and chemical raw materials is growing rapidly. In order to obtain better fuels and chemical raw materials, it is necessary to separate petroleum products according to their structure and properties and then utilize them respectively. Among them, the separation of aromatic hydrocarbon-alkane mixed systems is of great significance to the full utilization of petroleum. However, due to the similar physical and chemical properties of many aromatic hydrocarbons and alkanes, especially the boiling points of aromatic hydrocarbons and alkanes with similar carbon numbers are very close, and azeotropes are easily produced, it is difficult to economically and effectively separate them by conventional distillation. How to green and efficiently separate aromatic hydrocarbons and alkanes in petroleum distillates has become one of the most challenging problems in chemical separation. At present, researchers at home and abroad mainly use methods such as solvent extraction, extractive distillation, and adsorption separation to separate aromatic hydrocarbon-alkane systems.

[0003] Solvent extraction is the most commonly used process in the separation of aromatic hydrocarbon-alkane systems at present. It mainly uses the different solubilities of aromatic hydrocarbons in organic solvents to separate aromatic hydrocarbons and alkanes. The efficiency of solvent extraction in separating aromatic hydrocarbons is very high, and different process routes are used according to the different extraction solvents used. Among them, new solvents such as ionic liquids and eutectic solvents with structural design characteristics are considered to be one of the most promising directions in the field of extraction separation due to their excellent physical and chemical properties. Deep eutectic solvents (DESs) are usually formed by hydrogen bonding between a certain stoichiometric ratio of hydrogen bond donors (HBD) and hydrogen bond acceptors (HBA) through hydrogen bonding. They have the characteristics of simple preparation, low vapor pressure, good solubility, environmental friendliness, reusability, and strong designability, and are called new ionic liquids. Since they were first reported in 2003, they have been widely used in the fields of electrochemistry, energy, and extraction solvents.

[0004] In 2012, Kareem et al. (Kareem M.A., Mjalli F.S., Hashim M.A., et al. Liquid-liquid equilibria for the ternary system (phosphonium based deep eutectic solvent-benzene-hexane) at different temperatures: A new solvent introduced [J]. Fluid Phase Equilibria, 2012, 314 (none): 52-59.) first used DES (TBPB+EG) to extract and separate aromatic hydrocarbons from aromatic-aliphatic mixtures, and the research results showed that DES could effectively separate benzene and hexane mixture, and it was found that the hydrogen bond donor (EG) played a major role in the extraction and separation process, while the hydrogen bond acceptor (TBPB) played a second role. DES achieved similar separation effect as organic solvent, but it was difficult to achieve high extraction effect and high selectivity at the same time.

[0005] Inspired by the research work of Kareem, more and more researchers began to study the extraction and separation ability of different DESs for aromatic hydrocarbons. Although it can be found from the reports on the separation of aromatic hydrocarbon-alkane system by DESs that the selectivity of DESs for aromatic hydrocarbons is high, the solubility of DESs for aromatic hydrocarbon compounds is weak, which leads to the low distribution coefficient of DESs for aromatic hydrocarbons, thereby limiting the application of DESs. At present, the focus of the development of DESs is to improve the solubility of DESs for aromatic hydrocarbons as much as possible on the basis of maintaining high selectivity.

[0006] Developing a eutectic solvent system suitable for the separation of aromatic hydrocarbons in different fraction segments of petroleum products has certain economic value and social significance for the upgrading and efficiency of aromatic hydrocarbon extraction technology, and the expansion of aromatic hydrocarbon production raw materials and products. SUMMARY

[0007] The purpose of the present application is to overcome the problem that DES is difficult to achieve high extraction effect and high selectivity at the same time in the separation of aromatic hydrocarbons in the prior art, and to provide a composition, a eutectic solvent and a preparation method and application thereof, and a method for extracting and separating aromatic hydrocarbons in petroleum fractions. The eutectic solvent prepared from the specific composition for extracting and separating aromatic hydrocarbons in petroleum fractions has no solvent residue in the raffinate, the subsequent aromatic hydrocarbon separation method is simple, the extraction effect is obviously improved; and compared with the commonly used extraction solvent, the eutectic solvent has higher selectivity for aromatic hydrocarbons.

[0008] In order to achieve the above-mentioned purpose, the present application provides a composition comprising 1-ethylpyridinium chloride and levulinic acid; wherein the molar ratio of 1-ethylpyridinium chloride to levulinic acid is 0.5-5:1, preferably 1-3:1.

[0009] The second aspect of the present application provides a deep eutectic solvent comprising hydrogen-bonded 1-ethylpyridinium chloride and levulinic acid.

[0010] In the prior art, sulfolane is usually used as an extraction solvent, but because the boiling point of sulfolane is within the boiling range of kerosene and diesel oil fractions, it is difficult to recover the solvent by distillation process, resulting in high energy consumption for separation; at the same time, sulfolane can be partially decomposed to produce corrosive sulfur-containing substances, which has a great impact on the long-term use of the device. The deep eutectic solvent with the structure described in the present application significantly overcomes the defects of sulfolane, has a wide liquid temperature range (-30 to 200℃), a large density difference with petroleum fractions, a very low saturated vapor pressure, and does not contain sulfur elements, etc. It is applied to extract and separate aromatic hydrocarbons in petroleum fractions. It can be extracted in a wide temperature range, and it is easy to separate from petroleum fractions. The raffinate oil obtained basically has no solvent residue, the subsequent aromatic hydrocarbon separation method is simple, the extraction effect is significantly improved, and the separation cost is saved.

[0011] The third aspect of the present application provides a preparation method of a deep eutectic solvent, which comprises: the deep eutectic solvent is obtained by melt reaction of the composition of the first aspect.

[0012] The fourth aspect of the present application provides an application of the deep eutectic solvent of the second aspect or the deep eutectic solvent prepared by the method of the third aspect in the extraction and separation of aromatic hydrocarbons.

[0013] The fifth aspect of the present application provides a method for extracting and separating aromatic hydrocarbons in petroleum fractions, which comprises:

[0014] (1) reversely contacting a petroleum fraction with a deep eutectic solvent to obtain raffinate oil and extract oil containing the deep eutectic solvent and aromatic hydrocarbons;

[0015] (2) separating the extract oil containing the deep eutectic solvent and aromatic hydrocarbons obtained in step (1) to obtain aromatic hydrocarbons and the deep eutectic solvent;

[0016] Wherein, the deep eutectic solvent in step (1) is the deep eutectic solvent of the second aspect or the deep eutectic solvent prepared by the method of the third aspect.

[0017] Through the above technical solutions, the beneficial effects of the present application include:

[0018] The low eutectic solvent prepared by the specific composition is used for extracting and separating aromatic hydrocarbons in a petroleum fraction, residual oil obtained by the extraction has no solvent residue, a subsequent aromatic hydrocarbon separation method is simple and easy to operate, the extraction effect is obviously improved, the treatment cost is greatly saved, and compared with existing common extraction solvents, the low eutectic solvent has higher aromatic hydrocarbon selectivity, and has a good application prospect in the field of petroleum fraction aromatic hydrocarbon separation.

[0019] The low eutectic solvent has the characteristics of simple preparation process, low corrosion to devices, easy recovery, green environmental protection and the like, and can provide a separation scheme for petroleum fraction component separation and utilization. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a nuclear magnetic resonance diagram of the low eutectic solvent described in Example 1;

[0021] Figure 2 is a DSC diagram of the low eutectic solvent described in Example 1;

[0022] Figure 3 is a process flow diagram of the extraction and separation of aromatic hydrocarbons in a petroleum fraction according to the present application.

[0023] BRIEF DESCRIPTION OF DRAWINGS

[0024] In Figure 3 , the low eutectic solvent is used for extracting and separating aromatic hydrocarbons in a petroleum fraction.

[0025] 1, extraction column; 2, solvent recovery column; 3, low eutectic solvent;

[0026] 4, petroleum fraction; 5, raffinate oil; 6, extract oil containing low eutectic solvent and aromatic hydrocarbons; 7, heat exchanger; 8, aromatic hydrocarbon component; 9, reboiler. DETAILED DESCRIPTION

[0027] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and the values are approximate values and should be understood to include values approximately near these ranges and values within these ranges. For ranges with endpoints, the endpoints are included in the ranges. For ranges without endpoints, the range extends to include any value approximately near the range. For ranges with endpoints and for ranges without endpoints, the ranges extend to include individual points within the range and individual points near the range.

[0028] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "top", "bottom" and the like is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0029] In the present application, the "top pressure" refers to absolute pressure without special instructions.

[0030] The present application provides a composition comprising 1-ethylpyridinium chloride and levulinic acid; wherein the molar ratio of 1-ethylpyridinium chloride to levulinic acid is 0.5-5:1, preferably 1-3:1.

[0031] The present inventors found in the research process that the composition uses 1-ethylpyridinium chloride and levulinic acid to cooperate and control the molar ratio of 1-ethylpyridinium chloride to levulinic acid in the range of 0.5-5:1, which is beneficial to prepare the low eutectic solvent described in the second aspect of the present application. When the molar ratio of 1-ethylpyridinium chloride to levulinic acid is lower than or higher than the range described in the present application, a stable and uniform hydrogen bond network cannot be formed between molecules, and thus the DES described in the present application cannot be obtained, which is equivalent to a mixture of two solid salts.

[0032] In the field, bromide salt is usually used as a hydrogen bond acceptor due to its advantages of being easy to obtain and easy to form DES. However, the present inventors found in the research process that the low eutectic solvent prepared by using chloride salt (1-ethylpyridinium chloride) as a hydrogen bond acceptor and cooperating with levulinic acid has high aromatic hydrocarbon selectivity when used for extracting and separating aromatic hydrocarbons in petroleum fractions, and the chloride salt (1-ethylpyridinium chloride) has more stable performance and is not easy to decompose.

[0033] In the present application, the molar ratio of 1-ethylpyridinium chloride to levulinic acid is 0.5-5:1, for example 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, and any value in the range formed by any two of these values, preferably 1-3:1. Using this preferred embodiment, it is more beneficial to obtain the low eutectic solvent described in the second aspect of the present application.

[0034] The second aspect of the present application provides a low eutectic solvent, which is a hydrogen bond connected 1-ethylpyridinium chloride and levulinic acid.

[0035] Characterized by nuclear magnetic resonance spectrum, it can be seen that the H at 12.08ppm of pure levulinic acid (LA) is shifted after the formation of DES, and the chemical shift is shifted from 12.08ppm to 12.27ppm. In the process of forming DES, the hydroxyl hydrogen on LA and the halogen anion Cl - form a hydrogen bond, so there is no shift of hydrogen position on the spectrum of EpyCl. According to the above analysis, hydrogen bond interaction occurs between EpyCl and LA, which indicates that the solvent with the structure described in the present application has been obtained, which can be referred to Figure 1 .

[0036] The schematic structure of the solvent of the present application can refer to formula (1). Formula (1) is a structural schematic diagram of Example 1 of the present application (at this time, the molar ratio of 1-ethylpyridine chloride salt to levulinic acid is 2:1).

[0037]

[0038] The low eutectic solvent provided by the present application has a wide liquid temperature range, which is beneficial to improve the extraction effect. Preferably, the solvent is in a liquid state in the range of -30 to 200℃.

[0039] The liquid temperature range of the solvent of the present application is measured by DSC method. From Figure 2 It can be seen that the freezing point of the DES is lower than -60℃.

[0040] The preparation method of the low eutectic solvent of the present application is not particularly limited, as long as the low eutectic solvent with the above structure can be prepared. In order to further improve the extraction performance of the low eutectic solvent, the present application also provides a preparation method of the low eutectic solvent. The preparation method provided by the present application has a simple process and can be widely applied.

[0041] Preferably, the present application provides a preparation method of a low eutectic solvent, which comprises: the low eutectic solvent is obtained by melt reaction of the composition of the first aspect.

[0042] According to the present application, preferably, the temperature of the melt reaction is 80-150℃, preferably 100-120℃, for example, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃ and any value in the range formed by any two of these values. With this preferred embodiment, it is further beneficial to obtain the low eutectic solvent of the present application with the above structure. When the temperature of the melt reaction is higher than the range of the present application, many side reactions occur and the impurities increase.

[0043] The time of the melt reaction is selected in a wide range to obtain the low eutectic solvent of the present application with the above structure. Preferably, the time of the melt reaction is 1-10h, preferably 3-5h.

[0044] According to the present application, preferably, the melt reaction is carried out under stirring.

[0045] The time and rate of the stirring are not particularly limited and can be appropriately selected according to the specific circumstances.

[0046] According to a specific embodiment of the present application, the composition of the first aspect is stirred under condensation reflux in an oil bath to obtain the low eutectic solvent.

[0047] The fourth aspect of the present application provides application of the eutectic solvent of the second aspect or the eutectic solvent prepared by the method of the third aspect in the extraction and separation of aromatic hydrocarbons, preferably in the extraction and separation of aromatic hydrocarbons in a petroleum fraction.

[0048] The eutectic solvent provided by the present application can be used to treat different raw materials or products in a petroleum fraction. Preferably, the petroleum fraction is selected from at least one of gasoline, diesel and kerosene.

[0049] The gasoline, kerosene and diesel provided by the present application have the conventional interpretation in the art, and the present application does not have a special limitation thereon.

[0050] Preferably, the diesel is light diesel.

[0051] The light diesel of the present application refers to diesel with a distillation range of 180-380℃.

[0052] The fifth aspect of the present application provides a method for extracting and separating aromatic hydrocarbons in a petroleum fraction, which comprises:

[0053] (1) reverse contacting a petroleum fraction with a eutectic solvent to obtain raffinate and extract oil containing the eutectic solvent and aromatic hydrocarbons;

[0054] (2) separating the extract oil containing the eutectic solvent and aromatic hydrocarbons of step (1) to obtain aromatic hydrocarbons and the eutectic solvent;

[0055] In the method provided by the present application, the eutectic solvent of step (1) is the eutectic solvent of the second aspect or the eutectic solvent prepared by the method of the third aspect.

[0056] In the method provided by the present application, the reverse contacting refers to the eutectic solvent contacting from top to bottom and the petroleum fraction contacting from bottom to top by gravity.

[0057] Preferably, the reverse contacting of step (1) is carried out in an extraction column, and the raffinate is obtained at the top of the column, and the extract oil containing the eutectic solvent and aromatic hydrocarbons is obtained at the bottom of the column.

[0058] The eutectic solvent provided by the present application can be used to extract the petroleum fraction in a wide temperature range, and is easy to separate from the petroleum fraction. In order to optimize the extraction effect, preferably, the reverse contacting conditions of step (1) include: the extraction temperature is 20-150℃, preferably 40-100℃.

[0059] According to the present application, preferably, the mass ratio of the eutectic solvent to the petroleum fraction is 0.5-15:1, preferably 1-10:1.

[0060] According to the present application, preferably, the separation in step (2) is carried out in a solvent recovery column, and the aromatics are obtained at the top of the column, and the eutectic solvent is obtained at the bottom of the column.

[0061] According to the present application, preferably, the separation in step (2) is carried out under conditions including that the temperature at the bottom of the column is 80-200°C, and the pressure at the top of the column is 1-10 kPa.

[0062] In the present application, the extraction column and the solvent recovery column are devices for realizing the purpose of extracting and separating the aromatics in the petroleum distillate, and are not particularly limited, and can be selected according to the conventional selection in the art.

[0063] The separation in the present application is not particularly limited, and can be carried out by using the conventional technical means in the art. Preferably, the separation is vacuum distillation. By using this preferred embodiment, the aromatics can be separated from the eutectic solvent in a simple manner.

[0064] The eutectic solvent in the present application can be recycled. Preferably, the eutectic solvent obtained at the bottom of the solvent recovery column is returned to the extraction column for recycling.

[0065] According to a preferred embodiment of the present application, the eutectic solvent 3 enters the extraction column 1 from the middle upper part, the petroleum distillate 4 enters the extraction column 1 from the middle lower part, the raffinate oil 5 (the raffinate oil rich in saturated hydrocarbons) flows out from the top of the extraction column after countercurrent extraction, the extract oil 6 containing the eutectic solvent and the aromatics is sent into the solvent recovery column 2 from the bottom of the extraction column through the heat exchanger 7, the aromatic component 8 is obtained at the top of the solvent recovery column 2, the eutectic solvent 3 is obtained at the bottom of the solvent recovery column 2, part of which is returned to the extraction column 1 through the heat exchanger 7 for recycling, and part of which is returned to the solvent recovery column 2 after being reboiled by the reboiler 9 to provide heat for the solvent recovery column 2.

[0066] The present application will be described in detail by way of examples below.

[0067] In the following examples, the extraction effect of the solvent is embodied by the distribution coefficient (D) and the selectivity (S).

[0068] The distribution coefficient (D) is the ratio of the actual mole fraction of the extract in the two phases (the extract phase and the raffinate phase) after the extraction system reaches equilibrium.

[0069] The selectivity (S) is the ratio of the distribution coefficients of the components to be separated, and quantitatively indicates the difficulty of separating the extraction agent from the system to be separated. The larger the S value, the better the separation effect.

[0070] The calculation formulae of the distribution coefficient (D) and the selectivity (S) are as follows:

[0071]

[0072]

[0073]

[0074] wherein x i is the mole fraction of aromatics, x j is the mole fraction of alkanes, and D arom is the distribution coefficient of aromatics, D alkane is the distribution coefficient of alkanes, I and II are the raffinate phase and the extract phase, respectively, and S represents the selectivity of the extraction solvent to the aromatics.

[0075] In the following examples, the mass ratio of the eutectic solvent to the petroleum fraction is referred to as the solvent-to-oil ratio.

[0076] Example 1

[0077] The hydrogen bond acceptor 1-ethylpyridine chloride (EpyCl) and the hydrogen bond donor levulinic acid (LA) were weighed, and the molar ratio of EpyCl to LA was 2:1. The mixture was stirred at a rotation speed of 300 r / min under condensation reflux at 100 °C for 3 h to obtain a DES. The synthesized DES was sealed and stored in a desiccator for use in extraction experiments.

[0078] An exemplary nuclear magnetic resonance spectrum of the DES prepared in Example 1 is shown in FIG. 1. As can be seen, the chemical shift of the H at 12.08 ppm in pure levulinic acid (LA) is shifted to 12.27 ppm after the formation of the DES. This indicates that a hydrogen bond interaction occurs between EpyCl and LA, proving the formation of the eutectic solvent having the structure described in the present application. Figure 1 An exemplary DSC graph of the DES prepared in Example 1 is shown in FIG. 2. As can be seen, the solvent is in a liquid state in the range of -30 to 200 °C.

[0079] Figure 2 The synthesized DES was used to extract 10 model oils at a solvent-to-oil ratio of 2:1 at 40 °C for 30 min, and the distribution coefficient and the selectivity of the aromatics were calculated. The compositions of the 10 model oils are shown in Table 1, and the extraction results are shown in Table 2.

[0080] Table 1

[0081] Table 1

[0082] Hydrocarbon mole fraction / % Model oil 1 Model oil 2 Model oil 3 Model oil 4 Model oil 5 n-Heptane 52.6 62.6 72.8 82.1 91.2 Toluene 47.4 37.4 27.2 17.9 8.8 Hydrocarbon mole fraction / % Model oil 6 Model oil 7 Model oil 8 Model oil 9 Model oil 10 Cyclohexane 47.7 57.6 68.2 79.0 90.1 Benzene 52.3 42.4 31.8 21.0 9.9

[0083] Example 2

[0084] The DES synthesized in Example 1 was used as the extraction solvent to extract model oil 4 in Table 1 at a solvent-to-oil ratio of 4:1 at 60 °C for 30 min, and the distribution coefficient and the selectivity of the aromatics were calculated. The results are shown in Table 2.

[0085] Example 3 ​

[0086] The DES synthesized in Example 1 was used as the extraction solvent, and the model oil 4 in Table 1 was subjected to single extraction for 30 min at 50°C at a solvent to oil ratio of 6:1. The distribution coefficient and aromatic selectivity were calculated, and the results are shown in Table 2.

[0087] Example 4

[0088] EpyCl and LA were weighed, and the molar ratio of EpyCl to LA was 1.5:1. The reaction was stirred at a condensation reflux speed of 300 rpm for 4 h in an oil bath at 120°C to obtain the DES. The synthesized DES was well sealed and stored in a desiccator for use in extraction experiments.

[0089] The DES synthesized in Example 1 was used as the extraction solvent, and the model oil 4 in Table 1 was subjected to single extraction for 30 min at 40°C at a solvent to oil ratio of 2:1. The distribution coefficient and aromatic selectivity were calculated, and the results are shown in Table 2.

[0090] Example 5

[0091] EpyCl and LA were weighed, and the molar ratio of EpyCl to LA was 2.5:1. The reaction was stirred at a condensation reflux speed of 300 rpm for 4 h in an oil bath at 120°C to obtain the DES. The synthesized DES was well sealed and stored in a desiccator for use in extraction experiments.

[0092] The DES synthesized in Example 1 was used as the extraction solvent, and the model oil 4 in Table 1 was subjected to single extraction for 30 min at 40°C at a solvent to oil ratio of 2:1. The distribution coefficient and aromatic selectivity were calculated, and the results are shown in Table 2.

[0093] Example 6

[0094] The method of Example 1 was followed, except that the molar ratio of the hydrogen bond acceptor 1-ethylpyridine chloride (EpyCl) and the hydrogen bond donor levulinic acid (LA) was 4:1 to obtain the DES. The synthesized DES was well sealed and stored in a desiccator for use in extraction experiments.

[0095] The DES synthesized in Example 1 was used as the extraction solvent, and the model oil 4 in Table 1 was subjected to single extraction for 30 min at 40°C at a solvent to oil ratio of 2:1. The distribution coefficient and aromatic selectivity were calculated, and the results are shown in Table 2.

[0096] Comparative Example 1

[0097] The DES synthesized in Example 1 was used as the extraction solvent, and the model oil 4 in Table 1 was subjected to single extraction for 30 min at 40°C at a solvent to oil ratio of 2:1. The distribution coefficient and aromatic selectivity were calculated, and the results are shown in Table 2.

[0098] Comparative Example 2

[0099] The model oil 4 in Table 1 is subjected to single extraction for 30 min at 40 DEG C with dimethyl sulfoxide as solvent and the ratio of agent to oil being 2:1, and the distribution coefficient and aromatic hydrocarbon selectivity are calculated, and the results are shown in Table 2.

[0100] Comparative Example 3

[0101] The model oil 4 in Table 1 is subjected to single extraction for 30 min at 40 DEG C with N,N-dimethylformamide (DMF) as solvent and the ratio of agent to oil being 2:1, and the distribution coefficient and aromatic hydrocarbon selectivity are calculated, and the results are shown in Table 2.

[0102] Comparative Example 4

[0103] The model oil 4 in Table 1 is subjected to single extraction for 30 min at 40 DEG C with N-methyl pyrrolidone (NMP) as solvent and the ratio of agent to oil being 2:1, and the distribution coefficient and aromatic hydrocarbon selectivity are calculated, and the results are shown in Table 2.

[0104] Comparative Example 5

[0105] The model oil 9 in Table 1 is subjected to single extraction for 30 min at 40 DEG C with dimethyl sulfoxide as solvent and the ratio of agent to oil being 2:1, and the distribution coefficient and aromatic hydrocarbon selectivity are calculated, and the results are shown in Table 2.

[0106] Comparative Example 6

[0107] The model oil 9 in Table 1 is subjected to single extraction for 30 min at 40 DEG C with DMF as solvent and the ratio of agent to oil being 2:1, and the distribution coefficient and aromatic hydrocarbon selectivity are calculated, and the results are shown in Table 2.

[0108] Comparative Example 7

[0109] The method of Example 1 is followed, except that 1-ethylpyridinium bromide is used as the hydrogen bond acceptor to obtain a DES. The synthesized DES is sealed well and stored in a desiccator for use in extraction experiments.

[0110] The model oil 4 in Table 1 is subjected to single extraction for 30 min at 40 DEG C with the synthesized DES and the ratio of agent to oil being 2:1, and the distribution coefficient and aromatic hydrocarbon selectivity are calculated, and the results are shown in Table 2.

[0111] Table 2

[0112] Extractant Model oil <![CDATA[D 烷烃 ]]>

[00007] D 芳烃 ]] [SA 芳烃 ]] Example 1 n EpyCl :n LA = 2 1 0.0073 0.2718 37.41 Example 1 n EpyCl :n LA =2]]> 2 0.0070 0.2711 38.52 Example 1 n EpyCl :n LA = 2 3 0.0066 0.2736 41.36 Example 1 n EpyCl :n LA = 2 4 0.0060 0.2755 45.60 Example 1 n EpyCl :n LA =2]]> 5 0.0055 0.3092 56.17 Example 1 n EpyCl :n LA =2]]> 6 0.0199 0.2351 11.79 Example 1 n EpyCl :n LA =2]]> 7 0.0186 0.2368 12.75 Example 1 n EpyCl :n LA = 2 8 0.0178 0.2377 13.32 Example 1 n EpyCl :n LA = 2 9 0.0146 0.2444 16.77 Example 1 n EpyCl :n LA = 2 10 0.0119 0.2513 21.09 Example 2 n EpyCl :n LA = 2 4 0.0039 0.1653 42.38 Example 3 n EpyCl :n LA = 2 4 0.0031 0.1194 38.52 Example 4 n EpyCl :n LA = 1.5 4 0.0041 0.1856 45.27 Example 5 n EpyCl :n LA = 2.5 4 0.0029 0.1371 47.28 Example 6 n EpyCl :n LA = 4 4 0.0013 0.0587 45.15 Comparative example 1 Sulfolane 4 0.0089 0.3988 44.82 Comparative example 2 Dimethyl sulfoxide 4 0.0093 0.2926 31.58 Comparative example 3 DMF 4 0.1029 0.702 6.82 Comparative example 4 NMP 4 0.2352 0.59 2.51 Comparative example 5 Sulfolane 9 0.2369 1.56 6.59 Comparative example 6 Dimethyl sulfoxide 9 0.3531 1.8696 5.30 Comparative example 7 n C2py :n LA = 2 4 0.0106 0.2885 27.11

[0113] As can be seen from the results in Table 2, the eutectic solvent provided by the present application has better extraction selectivity compared with conventional organic solvents, and is suitable for use as an aromatic hydrocarbon extraction solvent.

[0114] Example 7

[0115] The process flow is as shown inFigure 3 as shown.

[0116] The DES synthesized in Example 1 was used as the extraction solvent, and the gasoline fraction was countercurrently extracted at a solvent to oil ratio of 4:1, an extraction column temperature of 50°C, a solvent recovery column bottom temperature of 120°C, and a solvent recovery column top pressure of 3 kPa. The solvent was recovered by vacuum distillation, and the raffinate and extract were obtained. The composition results of the gasoline feedstock, raffinate, and extract are shown in Table 3.

[0117] As shown in Table 3, the N content of the raffinate did not increase relative to the gasoline feedstock, indicating that there was essentially no DES remaining in the raffinate.

[0118] Table 3

[0119] Gasoline feedstock Raffinate Extracted oil Yield, wt% / 75.5 24.5 N content, pg / g 5 4 / Hydrocarbon composition, wt% Paraffins 32.93 43.81 1.12 Naphthenes 6.03 7.98 0.28 Olefins 35.71 45.84 2.16 Aromatics 25.33 2.37 96.44 Total 100 100 100

[0120] Note: Yield = mass of raffinate (mass of extract) / mass of feedstock oil x 100%

[0121] Example 8

[0122] The process flow is shown in Figure 3 as shown.

[0123] The DES synthesized in Example 1 was used as the extraction solvent, and the light diesel fraction was countercurrently extracted at a solvent to oil ratio of 5:1, an extraction column temperature of 50°C, a solvent recovery column bottom temperature of 160°C, and a solvent recovery column top pressure of 1.5 kPa. The solvent was recovered by vacuum distillation, and the raffinate and extract were obtained. The composition results of the light diesel feedstock, raffinate, and extract are shown in Table 4.

[0124] As shown in Table 4, the N content of the raffinate did not increase relative to the diesel feedstock, indicating that there was essentially no DES remaining in the raffinate.

[0125] Table 4

[0126] Diesel feedstock Raffinate Extracted oil Yield, wt% 25.8 74.2 N content, pg / g 22 14 / Hydrocarbon composition, wt% Paraffins 13.4 42.6 2.0 Naphthenes 4.3 13.8 1.0 Single-ring aromatics 38.8 37.4 39.1 Polycyclic aromatics 43.5 6.2 57.9 Total aromatics 82.3 43.6 97.0 Total 100 100 100

[0127] The above detailed the preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application, and fall within the protection scope of the present application.

Claims

1. A method of making a deep eutectic solvent, the method comprising: The eutectic solvent is obtained by melt reaction of 1-ethylpyridinium chloride and levulinic acid. The molar ratio of 1-ethylpyridinium chloride to levulinic acid is 1-3:

1.

2. The method of claim 1, wherein, The eutectic solvent is liquid at -30-200℃.

3. The method of claim 1, wherein, The temperature of the melt reaction is 80-150℃; The time of the melt reaction is 1-10h.

4. The method of claim 3, wherein, The temperature of the melt reaction is 100-120℃; The time of the melt reaction is 3-5h.

5. Use of the eutectic solvent prepared by the method of any one of claims 1-4 in extraction and separation of aromatic hydrocarbons.

6. The use of claim 5, wherein, The eutectic solvent is used in extraction and separation of aromatic hydrocarbons in petroleum distillates.

7. A method for extraction and separation of aromatic hydrocarbons in petroleum distillates, the method comprising: (1) contacting a petroleum distillate with a eutectic solvent in a reverse direction to obtain raffinate and extract containing the eutectic solvent and aromatic hydrocarbons; (2) separating the extract containing the eutectic solvent and aromatic hydrocarbons obtained in step (1) to obtain aromatic hydrocarbons and eutectic solvent; The eutectic solvent in step (1) is prepared by the method of any one of claims 1-4.

8. The method of claim 7, wherein, The conditions of the reverse contact in step (1) include: temperature of 20-150℃; The mass ratio of eutectic solvent to petroleum distillate is 0.5-15:

1.

9. The method of claim 8, wherein, The conditions of the reverse contact in step (1) include: temperature of 40-100℃; The mass ratio of eutectic solvent to petroleum distillate is 1-10:

1.

10. The method of claim 7, wherein, The separation in step (2) is carried out in a solvent recovery column.

11. The method of claim 10, wherein, The conditions of the separation in step (2) include: column bottom temperature of 80-200℃; column top pressure of 0.1-10kPa.

12. The method of claim 7, wherein, The separation in step (2) is vacuum distillation.

13. The method of claim 10, wherein, The eutectic solvent obtained at the bottom of the solvent recovery column is recycled to step (1).

14. The method of claim 7, wherein, The petroleum distillate is selected from at least one of gasoline, diesel and kerosene.

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