A method for extracting oxygenated compounds from coal-based alpha-olefins using a deep eutectic solvent

Abstract

The present invention relates to the field of chemical separation technology, and in particular to a method for extracting oxygenated compounds in coal-based alpha-olefins using a low eutectic solvent. The method for extracting oxygenated compounds in coal-based alpha-olefins using a low eutectic solvent provided by the present invention comprises the following steps: extracting alpha-olefin oil products using a low eutectic solvent to obtain alpha-olefin oil products from which oxygenated compounds are removed and a low eutectic solvent rich in oxygenated compounds; wherein the low eutectic solvent is obtained by reacting a hydrogen bond acceptor and a hydrogen bond donor. The method for extracting oxygenated compounds in coal-based alpha-olefins using a low eutectic solvent of the present invention has high single extraction efficiency; a green low eutectic solvent is used as an extractant, which has good stability and low toxicity; and the extractant can be completely regenerated, with low regeneration energy consumption.

Description

Technical Field

[0001] The invention relates to the technical field of chemical separation, and in particular to a method for extracting oxygen-containing compounds in coal-based alpha-olefins using a low eutectic solvent. Background Art

[0002] Coal resources account for a large proportion of fossil energy reserves, and the development of clean coal chemical industry is important for the development of energy industry and energy strategic security. The high-value utilization of Fischer-Tropsch synthetic oil and the development of low-energy consumption, low-pollution, low-emission and low-cost green utilization technology are important ways to achieve sustainable development of coal chemical industry and enable carbon peak and carbon neutrality. The α-olefin content in the light hydrocarbons synthesized by Fischer-Tropsch indirect liquefaction of coal exceeds 60wt%, and does not contain impurities such as sulfur, nitrogen and aromatics. Therefore, Fischer-Tropsch synthetic oil is suitable as a raw material for the production of α-olefins, and has huge cost advantages over the petroleum route. Fischer-Tropsch synthetic oil can be separated into high-purity single-carbon α-olefins through pre-separation, removal of oxygenated organic matter, separation of alkanes and alkenes, and refining; the oxygenated organic matter mainly includes organic acids, alcohols, aldehydes, ketones, esters, etc., and the content is about 5wt%. Organic acids in α-olefin oil products are generally removed by alkali washing. The separation methods of oxygenated organic matter such as alcohols, aldehydes, ketones, esters in α-olefin oil products mainly include adsorption, hydrogenation, distillation, solvent extraction, etc. Among them, the solvent extraction method has simple equipment, simple operation and low energy consumption, but there are problems such as the organic solvent is volatile, highly toxic and has low extraction efficiency. The solvent extraction method can be used for the rough removal of oxygen-containing compounds and is used in series with the fine removal of solid adsorbents. The key to this method is to select a highly selective and efficient extractant.

[0003] At present, the solvent extraction method generally uses organic solvents, salt solutions, mixed systems of organic solvents and water, and mixed systems of organic solvents and inorganic bases to extract oxygenated compounds in Fischer-Tropsch synthetic oil. Among them, the boiling point of organic solvents is generally significantly lower or higher than the extracted oxygenated compounds to facilitate the recovery and reuse of the extractant, but they are generally highly toxic and have low oil yields. Salt solutions are generally used to extract oxygenated compounds in alkanes and alkenes below C6. The oil yield of the mixed system of organic solvents and water is low, the oil loss is large, and the extractant needs to be recovered by distillation, which consumes a lot of energy.

[0004] In view of this, this invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a method for extracting oxygen-containing compounds in coal-based α-olefins using a low eutectic solvent, which has high single extraction efficiency; uses a green low eutectic solvent as an extractant, has good stability and low toxicity; and can achieve complete regeneration of the extractant with low regeneration energy consumption.

[0006] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0007] The present invention provides a method for extracting oxygen-containing compounds in coal-based alpha-olefins using a deep eutectic solvent, comprising the following steps:

[0008] The α-olefin oil product is extracted by using a deep eutectic solvent to obtain the α-olefin oil product from which oxygen-containing compounds are removed and the deep eutectic solvent rich in oxygen-containing compounds;

[0009] Wherein, the low eutectic solvent is obtained by reacting a hydrogen bond acceptor and a hydrogen bond donor.

[0010] Further, the hydrogen bond acceptor includes one or more of imidazolium salt, quaternary ammonium salt, ZnCl2 and choline chloride;

[0011] The hydrogen bond donor includes one or more of ethylene glycol, glycerol, xylitol, acetic acid, malonic acid, phosphoric acid and urea.

[0012] Furthermore, the chemical structure of the imidazolium salt is as follows:

[0013] Wherein, R1 is methyl, R2 is methyl or hydrogen, R3 is any one of C2 to C8 alkyl, and X is chlorine or bromine;

[0014] And / or, the chemical structure of the quaternary ammonium salt is as follows:

[0015] Wherein, R1, R2, R3 and R4 are each independently selected from any one of C1 to C8 alkyl groups, and X is chlorine or bromine.

[0016] Furthermore, the molar ratio of the hydrogen bond donor to the hydrogen bond acceptor is (1-3):1.

[0017] Furthermore, the temperature for the reaction of the hydrogen bond acceptor and the hydrogen bond donor is 75-85°C.

[0018] Furthermore, the mass ratio of the α-olefin oil product to the low eutectic solvent is (0.2-2):1.

[0019] Further, it includes at least one of the following features (1) to (3);

[0020] (1) The extraction temperature is 20 to 40° C.;

[0021] (2) The extraction time is 30 to 180 minutes;

[0022] (3) The stirring speed during the extraction process is 500 to 1200 r / min.

[0023] Further, it includes at least one of the following features (1) to (3);

[0024] (1) The α-olefin oil product includes C8-C10 α-olefins and oxygen-containing compounds;

[0025] (2) The oxygen-containing compound includes one or more of C5-C7 alcohol compounds, and C6-C8 aldehyde compounds, ketone compounds and ester compounds;

[0026] (3) The content of oxygen-containing compounds in the α-olefin oil product is 1 wt% to 5 wt%.

[0027] Furthermore, the oxygen-rich low eutectic solvent is subjected to reduced pressure flash evaporation to obtain a regenerated low eutectic solvent.

[0028] Furthermore, the pressure of the reduced pressure flash evaporation is 10-50 kPa, and the temperature is 100-200°C.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The method for extracting oxygen-containing compounds in coal-based α-olefins using a low eutectic solvent of the present invention has high single extraction efficiency.

[0031] 2. The method of extracting oxygen-containing compounds in coal-based α-olefins with a low eutectic solvent of the present invention uses a low eutectic solvent as an extractant, which has low toxicity and stable thermodynamic properties, and overcomes the shortcomings of traditional extractants such as high volatility, high toxicity and low selectivity.

[0032] 3. The method of extracting oxygen-containing compounds in coal-based α-olefins using a low eutectic solvent of the present invention can achieve complete regeneration of the extractant with low regeneration energy consumption. DETAILED DESCRIPTION

[0033] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0034] The following is a detailed description of a method for extracting oxygen-containing compounds in coal-based α-olefins using a low eutectic solvent according to the present invention.

[0035] In some embodiments of the present invention, a method for extracting oxygenated compounds in coal-based α-olefins using a deep eutectic solvent is provided, comprising the following steps:

[0036] The α-olefin oil product is extracted by using a deep eutectic solvent to obtain an α-olefin oil product (raffinate phase) from which oxygen-containing compounds are removed and a deep eutectic solvent (extract phase) rich in oxygen-containing compounds;

[0037] Among them, the deep eutectic solvent is obtained by the reaction of a hydrogen bond acceptor and a hydrogen bond donor.

[0038] The method for extracting oxygen-containing compounds in coal-based alpha-olefins by using a low eutectic solvent is suitable for the rough removal of oxygen-containing compounds in coal-based alpha-olefins and has high single extraction efficiency.

[0039] Environmentally friendly low eutectic solvents have the advantages of negligible vapor pressure, excellent solubility, high thermal stability, molecular designability, low cost, simple synthesis, low toxicity and biodegradability, and the atomic utilization rate during its synthesis is 100%. The low eutectic solvent is composed of a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA), which can provide protons or accept protons to form hydrogen bonds, so it has excellent solubility. The low eutectic solvent extraction method is a very green method. The present invention uses a low eutectic solvent as an extractant, which has low toxicity and stable thermodynamic properties, and overcomes the problems of high toxicity of the extractant, large volatilization loss, and high regeneration energy consumption in the removal of oxygen-containing compounds in coal-based α-olefins by traditional solvents.

[0040] In some embodiments of the present invention, the hydrogen bond acceptor (HBA) includes one or more of an imidazolium salt, a quaternary ammonium salt, ZnCl2, and choline chloride.

[0041] In some embodiments of the present invention, the chemical structure of the imidazolium salt is as follows:

[0042] Wherein, R1 is methyl, R2 is methyl or hydrogen, R3 is any one of C2 to C8 alkyl groups, and X is chlorine or bromine.

[0043] In some embodiments of the present invention, the imidazolium salt comprises 1-butyl-3-methylimidazole chloride.

[0044] In some embodiments of the present invention, the chemical structure of the quaternary ammonium salt is as follows:

[0045] Wherein, R1, R2, R3 and R4 are each independently selected from any one of C1 to C8 alkyl groups, and X is chlorine or bromine.

[0046] In some embodiments of the present invention, the quaternary ammonium salt comprises tetrabutylammonium bromide.

[0047] In some embodiments of the present invention, the hydrogen bond donor (HBD) includes one or more of ethylene glycol, glycerol, xylitol, acetic acid, malonic acid, phosphoric acid and urea.

[0048] The extraction effects of deep eutectic solvents synthesized with different hydrogen bond acceptors and hydrogen bond donors are different.

[0049] In some embodiments of the present invention, the molar ratio of the hydrogen bond donor (HBD) to the hydrogen bond acceptor (HBA) is (1-3):1; typically but not limiting, for example, the molar ratio of the hydrogen bond donor (HBD) to the hydrogen bond acceptor (HBA) can be 1:1, 1:1.5, 1:2, 1:2.5, 1:3 or a range of any two thereof.

[0050] The molar ratio of hydrogen bond acceptors to hydrogen bond donors in the deep eutectic solvent has a significant effect on the oxygen-containing compound removal rate, α-olefin recovery rate, and extractant loss rate; the present invention adopts the above molar ratio, which is beneficial to improving the extraction effect of the deep eutectic solvent.

[0051] In some embodiments of the present invention, the temperature of the reaction of the hydrogen bond acceptor (HBA) and the hydrogen bond donor (HBD) is 70-100°C; preferably, the reaction time is 12-48h; typically but not limiting, for example, the temperature of the reaction of HBA and HBD can be 70°C, 80°C, 90°C, 100°C or a range consisting of any two thereof; the reaction time can be 12h, 20h, 30h, 40h, 48h or a range consisting of any two thereof.

[0052] In some embodiments of the present invention, the mass ratio of the α-olefin oil product to the deep eutectic solvent is (0.2-2):1; typically but not limitatively, for example, the mass ratio of the α-olefin oil product to the deep eutectic solvent can be 0.2:1, 0.4:1, 0.6:1, 0.8:1, 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1 or a range of any two thereof.

[0053] In some embodiments of the present invention, the extraction temperature is 20-40°C; typically but not limiting, for example, the extraction temperature can be 20°C, 25°C, 30°C, 35°C, 40°C or a range of any two thereof.

[0054] In some embodiments of the present invention, the extraction is performed under normal pressure.

[0055] In some embodiments of the present invention, the extraction time is 30 to 180 min; typically but not limitatively, for example, the extraction time can be 30 min, 45 min, 60 min, 75 min, 90 min, 105 min, 120 min, 135 min, 150 min, 165 min, 180 min or a range consisting of any two of them.

[0056] In some embodiments of the present invention, the stirring speed during the extraction process is 500-1200 r / min; typically but not limitatively, for example, the stirring speed during the extraction process can be 500 r / min, 700 r / min, 900 r / min, 1100 r / min, 1200 r / min or a range of any two thereof.

[0057] In some embodiments of the present invention, after extraction, the process further comprises standing; preferably, the standing time is 0.5 to 5 h; typically but not limiting, for example, the standing time can be 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h or a range consisting of any two of them.

[0058] In some embodiments of the present invention, the α-olefin oil product includes C8-C10 α-olefins and oxygen-containing compounds.

[0059] In some embodiments of the present invention, the oxygen-containing compound includes C5-C7 alcohol compounds, and one or more of C6-C8 aldehyde compounds, ketone compounds and ester compounds.

[0060] In some embodiments of the present invention, the content of oxygen-containing compounds in the α-olefin oil product is 1 wt% to 5 wt%.

[0061] In some embodiments of the present invention, the oxygen-rich deep eutectic solvent is subjected to reduced pressure flash evaporation to obtain a regenerated deep eutectic solvent.

[0062] In some embodiments of the present invention, the pressure (absolute pressure) of the reduced pressure flash evaporation is 10-50 kPa, and the temperature is 100-200°C; typically but not limitatively, for example, the pressure of the reduced pressure flash evaporation can be 10 kPa, 20 kPa, 30 kPa, 40 kPa, 50 kPa or a range consisting of any two thereof; the temperature of the reduced pressure flash evaporation can be 100°C, 120°C, 140°C, 160°C, 180°C, 200°C or a range consisting of any two thereof.

[0063] The present invention adopts a low-pressure flash evaporation method to recover the low eutectic solvent in the extraction phase, which can achieve complete regeneration of the extractant with low regeneration energy consumption.

[0064] Example 1

[0065] The method for extracting oxygen-containing compounds in coal-based α-olefins using a deep eutectic solvent provided in this embodiment comprises the following steps:

[0066] C8 coal-based alpha-olefin oil products include the following components in terms of mass percentage:

[0067] 1-octene 95.62wt%, 1-pentanol 1.18wt%, 1-hexanal 1.34wt%, 2-hexanone 1.34wt% and ethyl butyrate 0.52wt%;

[0068] The hydrogen bond acceptor tetrabutylammonium bromide and the hydrogen bond donor ethylene glycol were mixed in a molar ratio of 1:1 and added into a round-bottom flask, and stirred at 80°C for 24 hours to obtain a low eutectic solvent;

[0069] The low eutectic solvent was mixed with the C8 coal-based α-olefin oil product in a mass ratio of 1:1, and liquid-liquid extraction was carried out in a liquid-liquid phase equilibrium kettle at normal pressure and 25°C. During the extraction process, the magnetic stirrer was stirred at 1000 r / min for 0.5 h. After the stirring was turned off and the mixture was allowed to stand for 3 h, an extract phase and a raffinate phase (hydrocarbon phase) were obtained.

[0070] Gas chromatography was used to detect the composition of the extraction phase and the raffinate phase. After calculation and analysis, the removal rate of oxygen-containing compounds in the C8 coal-based α-olefin oil was 60.4%, the total recovery rate of 1-octene in the hydrocarbon phase was 85.7%; and the content of the low eutectic solvent in the hydrocarbon phase was 0.102wt%.

[0071] Example 2

[0072] The method for extracting oxygen-containing compounds in coal-based α-olefins with a low eutectic solvent provided in this embodiment refers to Example 1, except that the mass ratio of the low eutectic solvent to the C8 coal-based α-olefin oil product is 1:2.

[0073] Gas chromatography was used to detect the composition of the extraction phase and the raffinate phase. After calculation and analysis, the removal rate of oxygen-containing compounds in the C8 coal-based α-olefin oil was 46.4%, the total recovery rate of 1-octene in the hydrocarbon phase was 92.6%; and the content of the low eutectic solvent in the hydrocarbon phase was 0.112wt%.

[0074] Example 3

[0075] The method for extracting oxygen-containing compounds in coal-based α-olefins with a low eutectic solvent provided in this embodiment refers to Example 1, except that the extraction temperature is 40°C.

[0076] Gas chromatography was used to detect the composition of the extraction phase and the raffinate phase. After calculation and analysis, the removal rate of oxygen-containing compounds in the C8 coal-based α-olefin oil was 60.8%, the total recovery rate of 1-octene in the hydrocarbon phase was 84.2%; and the content of the low eutectic solvent in the hydrocarbon phase was 0.168wt%.

[0077] Example 4

[0078] The method for extracting oxygen-containing compounds in coal-based α-olefins with a low eutectic solvent provided in this embodiment refers to Example 1, except that the molar ratio of the hydrogen bond acceptor tetrabutylammonium bromide to the hydrogen bond donor ethylene glycol is 1:2.

[0079] Gas chromatography was used to detect the composition of the extraction phase and the raffinate phase. After calculation and analysis, the removal rate of oxygen-containing compounds in the C8 coal-based α-olefin oil was 56.0%, the total recovery rate of 1-octene in the hydrocarbon phase was 89.6%; and the content of the low eutectic solvent in the hydrocarbon phase was 0.054wt%.

[0080] Example 5

[0081] The method for extracting oxygen-containing compounds in coal-based α-olefins with a low eutectic solvent provided in this embodiment refers to Example 1, except that the molar ratio of the hydrogen bond acceptor tetrabutylammonium bromide to the hydrogen bond donor ethylene glycol is 1:0.5.

[0082] Gas chromatography was used to detect the composition of the extraction phase and the raffinate phase. After calculation and analysis, the removal rate of oxygen-containing compounds in the C8 coal-based α-olefin oil was 63.6%; the total recovery rate of 1-octene in the hydrocarbon phase was 82.3%; and the content of low eutectic solvent in the hydrocarbon phase was 0.167%.

[0083] Example 6

[0084] The method for extracting oxygen-containing compounds in coal-based α-olefins with a low eutectic solvent provided in this embodiment refers to Example 1, except that the molar ratio of the hydrogen bond acceptor tetrabutylammonium bromide to the hydrogen bond donor ethylene glycol is 1:4.

[0085] Gas chromatography was used to detect the composition of the extraction phase and the raffinate phase. After calculation and analysis, the removal rate of oxygen-containing compounds in the C8 coal-based α-olefin oil was 51.7%; the total recovery rate of 1-octene in the hydrocarbon phase was 93.1%; and the content of low eutectic solvent in the hydrocarbon phase was 0.040%.

[0086] Example 7

[0087] The method for extracting oxygen-containing compounds in coal-based α-olefins with a low eutectic solvent provided in this embodiment refers to Example 1, except that the hydrogen bond acceptor tetrabutylammonium bromide and the hydrogen bond donor propylene glycol are mixed in a molar ratio of 1:3 and added to a round-bottom flask, and the reaction is stirred at 80°C for 24 hours to obtain a low eutectic solvent.

[0088] Gas chromatography was used to detect the composition of the extraction phase and the raffinate phase. After calculation and analysis, the removal rate of oxygen-containing compounds in the C8 coal-based α-olefin oil was 50.1%, the total recovery rate of 1-octene in the hydrocarbon phase was 93.7%; and the content of the low eutectic solvent in the hydrocarbon phase was 0.032wt%.

[0089] Example 8

[0090] The method for extracting oxygen-containing compounds in coal-based α-olefins with a low eutectic solvent provided in this embodiment refers to Example 1, except that the hydrogen bond acceptor tetrabutylammonium bromide and the hydrogen bond donor malonic acid are mixed in a molar ratio of 1:1 and added to a round-bottom flask, and the reaction is stirred at 80°C for 24 hours to obtain a low eutectic solvent.

[0091] Gas chromatography was used to detect the composition of the extraction phase and the raffinate phase. After calculation and analysis, the removal rate of oxygen-containing compounds in the C8 coal-based α-olefin oil was 42.9%; the total recovery rate of 1-octene in the hydrocarbon phase was 96.1%; and the content of the low eutectic solvent in the hydrocarbon phase was 0.013wt%.

[0092] Example 9

[0093] The method for extracting oxygen-containing compounds in coal-based α-olefins with a low eutectic solvent provided in this embodiment refers to Example 1, except that the hydrogen bond acceptor 1-butyl-3-methylimidazole chloride and the hydrogen bond donor ethylene glycol substance are mixed in a molar ratio of 1:1 and added to a round-bottom flask, and the reaction is stirred at 80°C for 24 hours to obtain a low eutectic solvent.

[0094] Gas chromatography was used to detect the composition of the extraction phase and the raffinate phase. After calculation and analysis, the removal rate of oxygen-containing compounds in the C8 coal-based α-olefin oil was 48.8%; the total recovery rate of 1-octene in the hydrocarbon phase was 93.9%; and the content of the low eutectic solvent in the hydrocarbon phase was 0.008wt%.

[0095] Example 10

[0096] The method for extracting oxygen-containing compounds in coal-based α-olefins with a low eutectic solvent provided in this embodiment refers to Example 1, except that the hydrogen bond acceptor ZnCl2 and the hydrogen bond donor acetic acid are mixed in a molar ratio of 1:1 and added to a round-bottom flask, and the reaction is stirred at 80°C for 24 hours to obtain a low eutectic solvent.

[0097] Gas chromatography was used to detect the composition of the extraction phase and the raffinate phase. After calculation and analysis, the removal rate of oxygen-containing compounds in the C8 coal-based α-olefin oil was 79.8%, the total recovery rate of 1-octene in the hydrocarbon phase was 95.2%; and the content of low eutectic solvent in the hydrocarbon phase was 0.291wt%.

[0098] Embodiment 11

[0099] The method for extracting oxygen-containing compounds in coal-based α-olefins using a deep eutectic solvent provided in this embodiment comprises the following steps:

[0100] The C8 coal-based α-olefin oil is the same as that in Example 1;

[0101] The hydrogen bond acceptor 1-butyl-3-methylimidazole chloride and the hydrogen bond donor ethylene glycol were mixed in a molar ratio of 1:1 and added into a round-bottom flask, and stirred for reaction at 80°C for 24 hours to obtain a low eutectic solvent;

[0102] The low eutectic solvent and the C8 coal-based α-olefin oil product were mixed in a mass ratio of 1:1, and liquid-liquid extraction was carried out using a liquid-liquid phase equilibrium kettle at normal pressure and 25°C. During the extraction process, the magnetic stirrer was stirred at 1000r / min for 0.5h. After the stirring was turned off and the mixture was allowed to stand for 3h, an extraction phase and a raffinate phase (hydrocarbon phase) were obtained. The extraction phase (the low eutectic solvent rich in oxides) was flash evaporated under reduced pressure at 20kPa (absolute pressure) and 120°C to obtain a regenerated low eutectic solvent. The regenerated low eutectic solvent was then used to repeat the above liquid-liquid extraction and standing for 5 times.

[0103] Gas chromatography was used to detect the composition of the last extraction phase and the raffinate phase. After calculation and analysis, the removal rate of oxygen-containing compounds in C8 coal-based α-olefin oil was 58.3%; the total recovery rate of 1-octene in the hydrocarbon phase was 84.9%; and the content of low eutectic solvent in the hydrocarbon phase was 0.107wt%.

[0104] Example 12

[0105] The method for extracting oxygen-containing compounds in coal-based α-olefins with a low eutectic solvent provided in this embodiment refers to Example 1, except that the C8 coal-based α-olefin oil product is replaced by a C10 coal-based α-olefin oil product; the C10 coal-based α-olefin oil product includes the following components, calculated in percentage: 95.50 wt% of 1-decene, 1.24 wt% of 1-heptanol, 1.37 wt% of 1-octanal, 1.37 wt% of 2-octanone and 0.52 wt% of ethyl hexanoate.

[0106] Gas chromatography was used to detect the composition of the extraction phase and the raffinate phase. After calculation and analysis, the removal rate of oxygen-containing compounds in the C8 coal-based α-olefin oil was 51.3%, the total recovery rate of 1-octene in the hydrocarbon phase was 91.0%; and the content of the low eutectic solvent in the hydrocarbon phase was 0.059wt%.

[0107] Test example

[0108] The compositions of the extract phase and the raffinate phase in Examples 1 to 12 were detected by gas chromatography. The oxygen-containing compound removal rate, α-olefin recovery rate and the extractant content in the oil product were obtained through calculation and analysis. The results are shown in Table 1.

[0109] Oxygen-containing compound removal rate = (mass of oxygen-containing compounds in C8 coal-based α-olefin oil products - mass of α-olefins in hydrocarbon phase) / mass of oxygen-containing compounds in C8 coal-based α-olefin oil products;

[0110] α-olefin recovery rate = mass of α-olefin in hydrocarbon phase / mass of α-olefin in C8 coal-based α-olefin oil product.

[0111] Table 1

[0112]

[0113]

[0114] As can be seen from Table 1, by comparing Example 1 with Example 2, by reducing the mass ratio of the deep eutectic solvent to the coal-based α-olefin product, the oxygen-containing compound removal rate is reduced and the α-olefin recovery rate is improved.

[0115] Comparing Example 1 with Example 3, increasing the temperature is beneficial to increasing the removal rate of oxygen-containing compounds, but at the same time the recovery rate of α-olefins is reduced and the loss rate of the extractant is increased.

[0116] Comparing Example 1 with Examples 4 to 6, the ratio of hydrogen bond acceptors to hydrogen bond donors in the deep eutectic solvent has a significant effect on the oxygen-containing compound removal rate, α-olefin recovery rate, and extractant loss rate.

[0117] Comparing Example 1 and Examples 7 to 10, the extraction effects of the low eutectic solvents synthesized with different hydrogen bond acceptors and hydrogen bond donors are different; among them, the low eutectic solvents in Example 1 and Examples 7 to 9 have a relatively low α-olefin recovery rate when the oxygen-containing compound removal rate is high; the low eutectic solvent of Example 10 has a better extraction effect, and at the same time has a higher oxygen-containing compound removal rate and α-olefin recovery rate.

[0118] Comparing Example 1 and Example 11, after the low eutectic solvent was reused and recycled 5 times, the oxygen-containing compound removal rate and the olefin recovery rate were slightly reduced, and the extractant loss rate was slightly increased, indicating that the low eutectic solvent has good reusability performance.

[0119] Comparing Example 1 and Example 12, as the carbon number of the oil product increases, the extraction difficulty increases, the oxygen-containing compound removal rate decreases, the α-olefin recovery rate increases, and the extraction agent loss rate decreases.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for extracting oxygen-containing compounds from coal-based α-olefins using a deep eutectic solvent, characterized in that: The steps include: The α-olefin oil product is extracted by using a deep eutectic solvent to obtain the α-olefin oil product from which oxygen-containing compounds are removed and the deep eutectic solvent rich in oxygen-containing compounds; Wherein, the low eutectic solvent is obtained by reacting a hydrogen bond acceptor and a hydrogen bond donor.

2. The method for extracting oxygen-containing compounds in coal-based α-olefins using a deep eutectic solvent according to claim 1, characterized in that: The hydrogen bond acceptor includes one or more of imidazolium salt, quaternary ammonium salt, ZnCl2 and choline chloride; The hydrogen bond donor includes one or more of ethylene glycol, glycerol, xylitol, acetic acid, malonic acid, phosphoric acid and urea.

3. The method for extracting oxygen-containing compounds in coal-based α-olefins using a deep eutectic solvent according to claim 2, characterized in that: The chemical structure of the imidazolium salt is shown below: Wherein, R1 is methyl, R2 is methyl or hydrogen, R3 is any one of C2 to C8 alkyl, and X is chlorine or bromine; And / or, the chemical structure of the quaternary ammonium salt is as follows: Wherein, R1, R2, R3 and R4 are each independently selected from any one of C1 to C8 alkyl groups, and X is chlorine or bromine.

4. The method for extracting oxygen-containing compounds in coal-based α-olefins using a deep eutectic solvent according to claim 1, characterized in that: The molar ratio of the hydrogen bond donor to the hydrogen bond acceptor is (1-3):

1.

5. The method for extracting oxygen-containing compounds in coal-based α-olefins using a deep eutectic solvent according to claim 1, characterized in that: The temperature for the reaction of the hydrogen bond acceptor and the hydrogen bond donor is 70-100°C.

6. The method for extracting oxygen-containing compounds in coal-based α-olefins using a deep eutectic solvent according to claim 1, characterized in that: The mass ratio of the α-olefin oil product to the low eutectic solvent is (0.2-2):

1.

7. The method for extracting oxygen-containing compounds in coal-based α-olefins using a deep eutectic solvent according to claim 1, characterized in that: The method comprises at least one of the following features (1) to (3); (1) The extraction temperature is 20 to 40° C.; (2) The extraction time is 30 to 180 minutes; (3) The stirring speed during the extraction process is 500 to 1200 r / min.

8. The method for extracting oxygen-containing compounds in coal-based α-olefins using a deep eutectic solvent according to claim 1, characterized in that: The method comprises at least one of the following features (1) to (3); (1) The α-olefin oil product includes C8-C10 α-olefins and oxygen-containing compounds; (2) The oxygen-containing compound includes one or more of C5-C7 alcohol compounds, and C6-C8 aldehyde compounds, ketone compounds and ester compounds; (3) The content of oxygen-containing compounds in the α-olefin oil product is 1 wt% to 5 wt%.

9. The method for extracting oxygen-containing compounds in coal-based α-olefins using a deep eutectic solvent according to claim 1, characterized in that: The oxygen-rich deep eutectic solvent is subjected to reduced pressure flash evaporation to obtain a regenerated deep eutectic solvent.

10. The method for extracting oxygen-containing compounds in coal-based α-olefins using a deep eutectic solvent according to claim 9, characterized in that: The pressure of the reduced pressure flash evaporation is 10-50 kPa, and the temperature is 100-200°C.

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