Preparation method and application of porous deep eutectic solvent

Abstract

The invention relates to a preparation method and application of a porous low eutectic solvent. Phosphoric acid is used as a hydrogen bond donor and a porous organosilicon quaternary ammonium salt is used as a hydrogen bond acceptor. The porous low eutectic solvent is prepared by modifying and grafting the quaternary ammonium salt on the surface of porous silica. The porous low eutectic solvent has the advantages of both the low eutectic solvent and the porous silica. The porous low eutectic solvent has not only a high specific surface area and high adsorption performance, so that the porous low eutectic solvent exhibits a good desulfurization rate in fuel oil desulfurization and realizes ultra-high efficiency deep desulfurization of fuel oil, but also has the characteristics of easy separation, non-volatility, strong thermal stability, non-toxicity and environmental protection. After the fuel oil desulfurization reaction is completed, the porous low eutectic solvent can be directly separated from the fuel oil, and the operation is convenient.

Description

Technical Field

[0001] The invention relates to the technical field of fuel oil desulfurization, in particular to a porous low eutectic solvent, and to a preparation method thereof and application in fuel oil desulfurization. Background Art

[0002] Sulfur oxides (SOx) and particulate matter (PM) formed by the combustion of sulfur compounds in fuel can cause acid rain and haze, causing serious environmental pollution and endangering public health. The presence of sulfur in crude oil processing can also cause catalyst deactivation, leading to corrosion problems in internal combustion engines and refinery parts. Faced with this serious problem, many countries have enacted regulations to limit the sulfur content in fuel (<100kg.mg-1). From an industrial and environmental perspective, achieving zero sulfur emissions in fuel has become an important development direction and research trend.

[0003] At present, hydrodesulfurization technology has been applied to produce low-sulfur diesel. However, this technology consumes a lot of hydrogen in the process of removing high-ignition-point and stubborn thiophene sulfides, and needs to operate under harsh conditions; this not only leads to a large amount of capital expenditure, but also does not meet environmental protection requirements. Therefore, it is necessary to develop an alternative or supplementary deep desulfurization technology that is cheap, energy-saving, and has mild operating conditions.

[0004] Among them, oxidative desulfurization technology has attracted much attention because it does not require the use of hydrogen and has mild reaction conditions; and the synthesis of new high-efficiency desulfurization catalysts and extractants is of great significance to the efficient development of oxidative desulfurization technology. Deep eutectic solvents (DES) are green alternatives to traditional ionic liquids and organic extractants. They have the advantages of simple synthesis, low cost, easy biodegradation, non-toxicity and easy availability of raw materials. They have been used in electrochemistry, separation, energy storage, synthesis and catalysis. However, the existing deep eutectic solvents have low desulfurization rates and are difficult to recycle during the process of fuel desulfurization. Therefore, it is necessary to provide a new technical solution to overcome the above defects. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a porous low eutectic solvent and its application which can effectively solve the above-mentioned technical problems.

[0006] In order to achieve the purpose of the present invention, the following technical scheme is adopted:

[0007] The present invention provides a method for preparing a porous deep eutectic solvent, comprising the following steps:

[0008] Step A: Preparation of porous organosilicon quaternary ammonium salt (OS-Cl@HS) as hydrogen bond acceptor;

[0009] Step B: Weigh a certain amount of phosphoric acid as a hydrogen bond donor and mix it with the porous organosilicon quaternary ammonium salt prepared in step A in a certain proportion and add it to a flask. After heating and stirring at a certain temperature for a period of time, a uniform liquid is obtained under the action of hydrogen bonds. After the uniform liquid is placed in a drying oven for a period of time, a porous low eutectic solvent (HS-DES) is obtained.

[0010] Preferably, the preparation steps of the porous organosilicon quaternary ammonium salt in step A are as follows:

[0011] Step A1: Weigh a certain amount of potassium sulfate (K 2 SO 4 ), 1,3,5-trimethylbenzene, triblock copolymer (F-127) and deionized water (50-60 mL) are mixed and stirred for 2-6 hours, and then tetramethoxysilane and (3-mercaptopropyl)trimethoxysilane are added and stirred for 20-24 hours, and then the mixture is transferred to a high-pressure reactor and fully reacted at a temperature of 80-120° C. to obtain a white mixture;

[0012] Step A2: filtering, washing, drying and calcining the white mixture obtained in step A1 to obtain a precursor, i.e., porous hollow silica (HS);

[0013] Step A3: Weigh 0.6-1.2 g of the porous hollow silica obtained in step A2 and place it in a beaker containing 10-20 mL of deionized water for ultrasonic treatment for 10-20 min, then add organosilicon quaternary ammonium salt at room temperature, stir thoroughly, and then stand for aging for one day, and then filter, wash, and dry to obtain porous organosilicon quaternary ammonium salt, which serves as a hydrogen bond acceptor.

[0014] Preferably, in step A1, the amount of potassium sulfate used is 0.5 to 1.0 g; the amount of 1,3,5-trimethylbenzene used is 0.5 to 1.0 mL; the amount of the triblock copolymer used is 1.0 to 1.5 g; the amount of tetramethoxysilane used is 1.5 to 3 g; and the amount of (3-mercaptopropyl)trimethoxysilane used is 0.5 to 1.0 g.

[0015] Preferably, in step A3, the mass ratio of the porous hollow silica to the organosilicon quaternary ammonium salt is (0.6-1.2):(0.1-1.0);

[0016] Preferably, the organosilicon quaternary ammonium salt is selected from a combination of one or more of 3-(trimethoxysilyl)propyl octadecyl dimethyl quaternary ammonium salt, 3-(trimethoxysilyl)propyl dodecyl dimethyl ammonium chloride, and 3-(trimethoxysilyl)propyl trimethyl ammonium chloride.

[0017] Preferably, in step B, the mass ratio of the porous organosilicon quaternary ammonium salt to phosphoric acid is (0.1-1.5):(0.5-3).

[0018] Preferably, in step B, the reaction temperature is 40-100° C., the reaction time is 3-8 h, the drying temperature is 80-120° C., and the drying time is 5-12 h.

[0019] In addition, the present invention also provides a porous low eutectic solvent prepared by the method described above; the porous low eutectic solvent can be used in fuel desulfurization.

[0020] Preferably, the steps of using a porous deep eutectic solvent to desulfurize fuel oil are as follows:

[0021] At room temperature, a certain amount of fuel oil and an appropriate amount of porous low eutectic solvent are weighed and added to a homemade reaction bottle, and then a certain amount of oxidant is added, and stirred for 5 to 360 minutes at a temperature of 20 to 80°C to carry out deep desulfurization; after the reaction is completed, the porous low eutectic solvent and the fuel oil are two phases, and the desulfurized fuel oil is directly precipitated to obtain the desulfurized fuel oil; the remaining porous low eutectic solvent can be recycled by back extraction operation.

[0022] Preferably, in the above-mentioned fuel desulfurization step:

[0023] Thiophene sulfides contained in the fuel oil;

[0024] The mass ratio of the fuel oil to the porous deep eutectic solvent is (1-20):(1-10);

[0025] The oxidant is hydrogen peroxide, the concentration of which is 10wt% to 30wt%, and the ratio of the amount of thiophene sulfide in the fuel oil is (1:1) to (10:1).

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention adopts phosphoric acid as a hydrogen bond donor and porous organosilicon quaternary ammonium salt as a hydrogen bond acceptor, and performs modification and grafting of quaternary ammonium salt on the surface of porous silica to prepare a porous deep eutectic solvent, so that the porous deep eutectic solvent has the advantages of both a deep eutectic solvent and porous silica. It not only has a high specific surface area and high adsorption performance, so that it exhibits a good desulfurization rate in fuel desulfurization, and realizes ultra-efficient deep desulfurization of fuel; it also has the characteristics of easy separation, non-volatility, strong thermal stability, non-toxicity, and environmental protection. After the fuel desulfurization reaction is completed, it can be directly separated from the fuel oil, and the operation is convenient.

[0028] 2. The porous low eutectic solvent of the present invention can be recycled multiple times with high utilization rate, thereby effectively reducing the desulfurization cost. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are partial embodiments of the present invention, rather than all embodiments.

[0030] The present invention provides a method for preparing a porous deep eutectic solvent, comprising the following steps:

[0031] Step A: preparing porous organosilicon quaternary ammonium salt (OS-Cl@HS) as a hydrogen bond acceptor; the preparation method thereof can adopt a template method, an ultrasonic emulsification method, a grafting substitution method, etc. The ultrasonic emulsification method is adopted in the present invention, and the specific steps are as follows:

[0032] Step A1: Weigh a certain amount of potassium sulfate (K 2 SO 4 ), 1,3,5-trimethylbenzene, triblock copolymer (F-127) and deionized water (50-60 mL) are mixed and stirred for 2-6 hours, and then tetramethoxysilane and (3-mercaptopropyl)trimethoxysilane are added and stirred for 20-24 hours, and then the mixture is transferred to a high-pressure reactor and fully reacted at a temperature of 80-120° C. to obtain a white mixture;

[0033] Step A2: filtering, washing, drying and calcining the white mixture obtained in step A1 to obtain a precursor, i.e., porous hollow silica (HS);

[0034] Step A3: Weigh 0.6-1.2 g of the porous hollow silica obtained in step A2, place it in a beaker containing 10-20 mL of deionized water, and ultrasonically treat it for 10-20 min. Then, add the organosilicon quaternary ammonium salt at room temperature, stir it thoroughly, and let it stand for aging for one day. Then, filter, wash, and dry to obtain the porous organosilicon quaternary ammonium salt.

[0035] Wherein, in the step A1, the amount of potassium sulfate used is 0.5 to 1.0 g; the amount of 1,3,5-trimethylbenzene used is 0.5 to 1.0 mL; the amount of the triblock copolymer used is 1.0 to 1.5 g; the amount of tetramethoxysilane used is 1.5 to 3 g; and the amount of (3-mercaptopropyl)trimethoxysilane used is 0.5 to 1.0 g.

[0036] In the step A3, the mass ratio of the porous hollow silica to the organosilicon quaternary ammonium salt is (0.6-1.2):(0.1-1.0);

[0037] The organosilicon quaternary ammonium salt is selected from one or more of 3-(trimethoxysilyl)propyl octadecyl dimethyl quaternary ammonium salt, 3-(trimethoxysilyl)propyl dodecyl dimethyl ammonium chloride, 3-(trimethoxysilyl)propyl trimethyl ammonium chloride and the like.

[0038] The structural formula of the porous organosilicon quaternary ammonium salt is as follows:

[0039]

[0040] Step B: Weigh a certain amount of phosphoric acid as a hydrogen bond donor and mix it with the porous organosilicon quaternary ammonium salt prepared in step A in a certain proportion and add it to a flask, heat and stir the reaction at a temperature of 40 to 100° C. for 3 to 8 hours, and obtain a uniform liquid under the action of hydrogen bonding. Place the uniform liquid in a drying oven at a drying temperature of 80 to 120° C. and dry it for 5 to 12 hours to obtain a porous low eutectic solvent (HS-DES).

[0041] In addition, the present invention also provides a porous low eutectic solvent prepared by the method described above; the porous low eutectic solvent can be used in fuel desulfurization.

[0042] Specifically, the steps of using a porous deep eutectic solvent to desulfurize fuel oil are as follows:

[0043] At room temperature, a certain amount of fuel oil and an appropriate amount of porous low eutectic solvent are weighed and added to a homemade reaction bottle, and then a certain amount of oxidant is added, and stirred for 5 to 360 minutes at a temperature of 20 to 80°C to carry out deep desulfurization; after the reaction is completed, the porous low eutectic solvent and the fuel oil are two phases, and the desulfurized fuel oil is directly precipitated to obtain the desulfurized fuel oil; the remaining porous low eutectic solvent can be recycled by back extraction operation.

[0044] Among them, in the above fuel desulfurization step:

[0045] The thiophene sulfides contained in the fuel oil specifically include one or more of benzothiophene (BT), 3-methylbenzothiophene (3-MBT), dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT) or 4,6-dimethyldibenzothiophene (4,6-DMDBT).

[0046] The mass ratio of the fuel oil to the porous deep eutectic solvent is (1-20):(1-10).

[0047] The oxidant is hydrogen peroxide with a concentration of 10wt% to 30wt%, and the molar ratio of the hydrogen peroxide to the thiophene sulfide in the fuel oil is (1:1) to (10:1).

[0048] Example 1

[0049] Preparation of porous deep eutectic solvent-1:

[0050] Step A: Preparation of porous organosilicon quaternary ammonium salt (OS-Cl@HS) as hydrogen bond acceptor;

[0051] Step A1: Weigh 0.5 g of potassium sulfate (K 2 SO 4 ), 1.0 mL of 1,3,5-trimethylbenzene, 1.5 g of triblock copolymer (F-127) and 60 mL of deionized water were mixed and stirred for 5 h, and then 1.5 g of tetramethoxysilane and 0.5 g of (3-mercaptopropyl) trimethoxysilane were added and stirred for 20 h, and then the mixture was transferred to a high-pressure reactor and fully reacted at 80 ° C to obtain a white mixture;

[0052] Step A2: filtering, washing, drying, calcining, and other steps of the white mixture obtained in step A1 to obtain a precursor, i.e., porous hollow silica (HS);

[0053] Step A3: Weigh 0.6 g of the porous hollow silica obtained in step A2 and place it in a beaker containing 10 mL of deionized water for ultrasonic treatment for 10 min, then add 0.1 g of 3-(trimethoxysilyl)propyl octadecyl dimethyl quaternary ammonium salt at room temperature, stir well, and let stand for aging for one day, then filter, wash, and dry to obtain a porous organosilicon quaternary ammonium salt.

[0054] Step B: Weigh 0.5 g of phosphoric acid as a hydrogen bond donor and mix it with 0.1 g of the porous organosilicon quaternary ammonium salt prepared in step A and add it to a flask. Heat and stir the reaction at 80°C for 4 hours to obtain a uniform liquid under the action of hydrogen bonds. Place the uniform liquid in a drying oven at a drying temperature of 100°C. After drying for 8 hours, porous low eutectic solvent-1 is obtained.

[0055] Model oil preparation:

[0056] Dibenzothiophene (DBT) was dissolved in n-dodecane solution to prepare a DBT model oil with a sulfur content of 200 ppm.

[0057] Desulfurization test:

[0058] 0.1 g of porous deep eutectic solvent-1 was added to 2.5 g of DBT model oil with a sulfur content of 200 ppm, and then 30 wt% H 2 O 2 , H 2 O 2 The molar ratio of the substance to DBT was 5:1. The stirring was stopped after 15 minutes at 20°C. At this time, the porous low eutectic solvent-1 was in the lower layer and the model oil was in the upper layer. GC-FID was used to detect the DBT content in the model oil. The removal rate of the model oil was calculated to be 84.8%.

[0059] Example 2

[0060] Preparation of porous deep eutectic solvent-2:

[0061] Step A: Preparation of porous organosilicon quaternary ammonium salt (OS-Cl@HS) as hydrogen bond acceptor;

[0062] Step A1: Weigh 0.8 g of potassium sulfate (K 2 SO 4 ), 1.0 mL of 1,3,5-trimethylbenzene, 1.5 g of triblock copolymer (F-127) and 60 mL of deionized water were mixed and stirred for 4 h, and then 2.0 g of tetramethoxysilane and 1.0 g of (3-mercaptopropyl) trimethoxysilane were added and stirred for 24 h, and then the mixture was transferred to a high-pressure reactor and fully reacted at a temperature of 100 ° C to obtain a white mixture;

[0063] Step A2: filtering, washing, drying, calcining, and other steps of the white mixture obtained in step A1 to obtain a precursor, i.e., porous hollow silica (HS);

[0064] Step A3: Weigh 1.2 g of the porous hollow silica obtained in step A2 and place it in a beaker containing 15 mL of deionized water for ultrasonic treatment for 15 min, then add 0.5 g of 3-(trimethoxysilyl)propyldodecyldimethylammonium chloride at room temperature, stir well, and let stand for aging for one day, then filter, wash, and dry to obtain a porous organosilicon quaternary ammonium salt.

[0065] Step B: Weigh 1.0 g of phosphoric acid as a hydrogen bond donor and mix it with 0.5 g of the porous organosilicon quaternary ammonium salt prepared in step A and add it to a flask. Heat and stir the reaction at 80°C for 4 hours to obtain a uniform liquid under the action of hydrogen bonds. Place the uniform liquid in a drying oven at a drying temperature of 120°C. After drying for 8 hours, porous low eutectic solvent-2 is obtained.

[0066] Model oil preparation:

[0067] Dibenzothiophene (DBT) was dissolved in n-dodecane solution to prepare a DBT model oil with a sulfur content of 500 ppm.

[0068] Desulfurization test:

[0069] 1 g of porous deep eutectic solvent-2 was added to 2 g of DBT model oil with a sulfur content of 500 ppm, and then 15 wt% H 2 O 2 , H 2 O 2 The molar ratio of the substance to DBT is 2:1. The stirring is stopped at 40°C after 60 minutes. At this time, the porous low eutectic solvent-2 is in the lower layer and the model oil is in the upper layer. GC-FID is used to detect the DBT content in the model oil. The removal rate of the model oil is calculated to be 98.7%.

[0070] Example 3

[0071] Preparation of porous deep eutectic solvent-3:

[0072] Step A: Preparation of porous organosilicon quaternary ammonium salt (OS-Cl@HS) as hydrogen bond acceptor;

[0073] Step A1: Weigh 1.0 g of potassium sulfate (K 2 SO 4 ), 0.8 mL of 1,3,5-trimethylbenzene, 1.0 g of triblock copolymer (F-127) and 60 mL of deionized water were mixed and stirred for 4 h, and then 3.0 g of tetramethoxysilane and 1.5 g of (3-mercaptopropyl) trimethoxysilane were added and stirred for 24 h, and then the mixture was transferred to a high-pressure reactor and fully reacted at a temperature of 120 ° C to obtain a white mixture;

[0074] Step A2: filtering, washing, drying, calcining, and other steps of the white mixture obtained in step A1 to obtain a precursor, i.e., porous hollow silica (HS);

[0075] Step A3: Weigh 1.2 g of the porous hollow silica obtained in step A2 and place it in a beaker containing 15 mL of deionized water for ultrasonic treatment for 15 min, then add 0.5 g of 3-(trimethoxysilyl)propyltrimethylammonium chloride at room temperature, stir thoroughly, and let stand for aging for one day, then filter, wash, and dry to obtain a porous organosilicon quaternary ammonium salt.

[0076] Step B: Weigh 2.0 g of phosphoric acid as a hydrogen bond donor and mix it with 1.0 g of the porous organosilicon quaternary ammonium salt prepared in step A and add it to a flask. Heat and stir the reaction at 80°C for 4 hours to obtain a uniform liquid under the action of hydrogen bonds. Place the uniform liquid in a drying oven at a drying temperature of 120°C. After drying for 8 hours, porous low eutectic solvent-3 is obtained.

[0077] Model oil preparation:

[0078] Dibenzothiophene (DBT) was dissolved in n-dodecane solution to prepare a DBT model oil with a sulfur content of 200 ppm.

[0079] Desulfurization test:

[0080] 4 g of porous low eutectic solvent-3 was added to 3 g of DBT model oil with a sulfur content of 200 ppm, and then 30 wt% H 2 O 2 , H 2 O 2The molar ratio of the substance to DBT was 10:1. The stirring was stopped at 50°C after 360 minutes. At this time, the porous low eutectic solvent-3 was in the lower layer and the model oil was in the upper layer. GC-FID was used to detect the DBT content in the model oil. The removal rate of the model oil was calculated to be 99.9%.

[0081] Example 4

[0082] Preparation of porous deep eutectic solvent-4:

[0083] Step A: Preparation of porous organosilicon quaternary ammonium salt (OS-Cl@HS) as hydrogen bond acceptor;

[0084] Step A1: Weigh 0.5 g of potassium sulfate (K 2 SO 4 ), 0.8 mL of 1,3,5-trimethylbenzene, 1.0 g of triblock copolymer (F-127) and 55 mL of deionized water were mixed and stirred for 5 h, and then 1.2 g of tetramethoxysilane and 1.0 g of (3-mercaptopropyl)trimethoxysilane were added and stirred for 24 h, and then the mixture was transferred to a high-pressure reactor and fully reacted at 80 ° C to obtain a white mixture;

[0085] Step A2: filtering, washing, drying, calcining, and other steps of the white mixture obtained in step A1 to obtain a precursor, i.e., porous hollow silica (HS);

[0086] Step A3: Weigh 0.6 g of the porous hollow silica obtained in step A2 and place it in a beaker containing 20 mL of deionized water for ultrasonic treatment for 10 min, then add 0.5 g of 3-(trimethoxysilyl)propyl octadecyl dimethyl quaternary ammonium salt at room temperature, stir well, and then stand for aging for one day, then filter, wash, and dry to obtain a porous organosilicon quaternary ammonium salt.

[0087] Step B: Weigh 1.0 g of phosphoric acid as a hydrogen bond donor and mix it with 0.1 g of the porous organosilicon quaternary ammonium salt prepared in step A and add it to a flask. Heat and stir the reaction at 80°C for 8 hours to obtain a uniform liquid under the action of hydrogen bonds. Place the uniform liquid in a drying oven at a drying temperature of 100°C. After drying for 8 hours, porous low eutectic solvent-4 is obtained.

[0088] Model oil preparation:

[0089] Benzothiophene (BT) was dissolved in n-dodecane solution to prepare a BT model oil with a sulfur content of 200 ppm.

[0090] Desulfurization test:

[0091] 1 g of porous deep eutectic solvent-4 was added to 2.5 g of BT model oil with a sulfur content of 200 ppm, and then 30 wt% H 2 O 2 , H 2 O 2 The molar ratio of BT to DBT was 5:1. The stirring was stopped at 60°C after 120 minutes. At this time, the porous low eutectic solvent-4 was in the lower layer and the model oil was in the upper layer. GC-FID was used to detect the BT content in the model oil. The removal rate of the model oil was calculated to be 89.1%.

[0092] Example 5

[0093] Preparation of porous deep eutectic solvent-5:

[0094] Step A: Preparation of porous organosilicon quaternary ammonium salt (OS-Cl@HS) as hydrogen bond acceptor;

[0095] Step A1: Weigh 1.0 g of potassium sulfate (K 2 SO 4 ), 1.5 mL of 1,3,5-trimethylbenzene, 0.5 g of triblock copolymer (F-127) and 60 mL of deionized water were mixed and stirred for 5 h, and then 3.0 g of tetramethoxysilane and 1.5 g of (3-mercaptopropyl) trimethoxysilane were added and stirred for 20 h, and then the mixture was transferred to a high-pressure reactor and fully reacted at a temperature of 100 ° C to obtain a white mixture;

[0096] Step A2: filtering, washing, drying, calcining, and other steps of the white mixture obtained in step A1 to obtain a precursor, i.e., porous hollow silica (HS);

[0097] Step A3: Weigh 1.0 g of the porous hollow silica obtained in step A2 and place it in a beaker containing 15 mL of deionized water for ultrasonic treatment for 15 min, then add 0.5 g of 3-(trimethoxysilyl)propyldodecyldimethylammonium chloride at room temperature, stir well, and let stand for aging for one day, then filter, wash, and dry to obtain a porous organosilicon quaternary ammonium salt.

[0098] Step B: Weigh 1.0 g of phosphoric acid as a hydrogen bond donor and mix it with 0.1 g of the porous organosilicon quaternary ammonium salt prepared in step A and add it to a flask. Heat and stir the reaction at 100°C for 6 hours to obtain a uniform liquid under the action of hydrogen bonds. Place the uniform liquid in a drying oven at a drying temperature of 80°C. After drying for 12 hours, porous low eutectic solvent-5 is obtained.

[0099] Model oil preparation:

[0100] 4,6-Dimethyldiphenylbenzothiophene (4,6-DMDBT) was dissolved in n-dodecane solution to prepare a 4,6-DMDBT model oil with a sulfur content of 200 ppm.

[0101] Desulfurization test:

[0102] 1 g of porous deep eutectic solvent-5 was added to 5 g of 4,6-DMDBT model oil with a sulfur content of 200 ppm, and then 15 wt% H 2 O 2 , H 2 O 2 The molar ratio of 4,6-DMDBT to DBT was 10:1. The stirring was stopped at 60°C for 60 minutes. At this time, the porous low eutectic solvent-5 was in the lower layer and the model oil was in the upper layer. GC-FID was used to detect the content of 4,6-DMDBT in the model oil. The removal rate of the model oil was calculated to be 76.1%.

[0103] Example 6

[0104] Preparation of porous deep eutectic solvent-6:

[0105] Step A: Preparation of porous organosilicon quaternary ammonium salt (OS-Cl@HS) as hydrogen bond acceptor;

[0106] Step A1: Weigh 0.8 g of potassium sulfate (K 2 SO 4 ), 1.0 mL of 1,3,5-trimethylbenzene, 1.0 g of triblock copolymer (F-127) and 60 mL of deionized water were mixed and stirred for 6 h, and then 2.0 g of tetramethoxysilane and 1.0 g of (3-mercaptopropyl)trimethoxysilane were added and stirred for 24 h, and then the mixture was transferred to a high-pressure reactor and fully reacted at a temperature of 100 ° C to obtain a white mixture;

[0107] Step A2: filtering, washing, drying, calcining, and other steps of the white mixture obtained in step A1 to obtain a precursor, i.e., porous hollow silica (HS);

[0108] Step A3: Weigh 1.5 g of the porous hollow silica obtained in step A2 and place it in a beaker containing 15 mL of deionized water for ultrasonic treatment for 15 min, then add 1.0 g of 3-(trimethoxysilyl)propyltrimethylammonium chloride at room temperature, stir thoroughly, and then stand for aging for one day, then filter, wash, and dry to obtain a porous organosilicon quaternary ammonium salt.

[0109] Step B: Weigh 3.0 g of phosphoric acid as a hydrogen bond donor and mix it with 0.5 g of the porous organosilicon quaternary ammonium salt prepared in step A and add it to a flask. Heat and stir the reaction at 80°C for 4 hours to obtain a uniform liquid under the action of hydrogen bonds. Place the uniform liquid in a drying oven at a drying temperature of 120°C. After drying for 8 hours, porous low eutectic solvent-6 is obtained.

[0110] Model oil preparation:

[0111] 4-Methyldiphenylbenzothiophene (4-MDBT) was dissolved in n-dodecane solution to prepare a 4-MDBT model oil with a sulfur content of 800 ppm.

[0112] Desulfurization test:

[0113] 1 g of porous deep eutectic solvent-6 was added to 2 g of 4-MDBT model oil with a sulfur content of 800 ppm, and then 10 wt% H 2 O 2 , H 2 O 2 The molar ratio of the substance to 4-MDBT was 8:1. The stirring was stopped at 30°C after 60 minutes. At this time, the porous low eutectic solvent-6 was in the lower layer and the model oil was in the upper layer. GC-FID was used to detect the content of 4-MDBT in the model oil. The removal rate of the model oil was calculated to be 86.7%.

[0114] Example 7

[0115] Preparation of porous deep eutectic solvent-7:

[0116] Step A: Preparation of porous organosilicon quaternary ammonium salt (OS-Cl@HS) as hydrogen bond acceptor;

[0117] Step A1: Weigh 1.0 g of potassium sulfate (K 2 SO 4 ), 1.0 mL of 1,3,5-trimethylbenzene, 1.5 g of triblock copolymer (F-127) and 50 mL of deionized water were mixed and stirred for 2 h, and then 3.0 g of tetramethoxysilane and 1.0 g of (3-mercaptopropyl)trimethoxysilane were added and stirred for 24 h, and then the mixture was transferred to a high-pressure reactor and fully reacted at a temperature of 100 ° C to obtain a white mixture;

[0118] Step A2: filtering, washing, drying, calcining, and other steps of the white mixture obtained in step A1 to obtain a precursor, i.e., porous hollow silica (HS);

[0119] Step A3: Weigh 1.2 g of the porous hollow silica obtained in step A2 and place it in a beaker containing 20 mL of deionized water for ultrasonic treatment for 20 min, then add 1.0 g of 3-(trimethoxysilyl)propyl octadecyl dimethyl quaternary ammonium salt at room temperature, stir thoroughly, and then stand for aging for one day, then filter, wash, and dry to obtain a porous organosilicon quaternary ammonium salt.

[0120] Step B: Weigh 2.0 g of phosphoric acid as a hydrogen bond donor and mix it with 0.5 g of the porous organosilicon quaternary ammonium salt prepared in step A and add it to a flask. Heat and stir the reaction at 120°C for 8 hours. A uniform liquid is obtained under the action of hydrogen bonds. The uniform liquid is placed in a drying oven at a drying temperature of 100°C. After drying for 12 hours, the porous low eutectic solvent-7 is obtained.

[0121] Model oil preparation:

[0122] 3-Methylbenzothiophene (3-MBT) was dissolved in n-dodecane solution to prepare a 3-MBT model oil with a sulfur content of 1000 ppm.

[0123] Desulfurization test:

[0124] 1 g of porous deep eutectic solvent-7 was added to 2.5 g of 3-MBT model oil with a sulfur content of 1000 ppm, and then 30 wt% H 2 O 2 , H 2 O 2 The molar ratio of the substance to 3-MBT was 6:1. The stirring was stopped at 50°C after 360 minutes. At this time, the porous low eutectic solvent-7 was in the lower layer and the model oil was in the upper layer. GC-FID was used to detect the content of 3-MBT in the model oil. The removal rate of the model oil was calculated to be 78.1%.

[0125] Example 8

[0126] Preparation of porous deep eutectic solvent-8:

[0127] Step A: Preparation of porous organosilicon quaternary ammonium salt (OS-Cl@HS) as hydrogen bond acceptor;

[0128] Step A1: Weigh 1.0 g of potassium sulfate (K 2 SO 4 ), 0.8 mL of 1,3,5-trimethylbenzene, 0.5 g of triblock copolymer (F-127) and 60 mL of deionized water were mixed and stirred for 5 h, and then 3.0 g of tetramethoxysilane and 1.5 g of (3-mercaptopropyl)trimethoxysilane were added and stirred for 20 h, and then the mixture was transferred to a high-pressure reactor and fully reacted at a temperature of 100 ° C to obtain a white mixture;

[0129] Step A2: filtering, washing, drying, calcining, and other steps of the white mixture obtained in step A1 to obtain a precursor, i.e., porous hollow silica (HS);

[0130] Step A3: Weigh 1.0 g of the porous hollow silica obtained in step A2 and place it in a beaker containing 15 mL of deionized water for ultrasonic treatment for 15 min, then add 0.5 g of 3-(trimethoxysilyl)propyldodecyldimethylammonium chloride at room temperature, stir well, and let stand for aging for one day, then filter, wash, and dry to obtain a porous organosilicon quaternary ammonium salt.

[0131] Step B: Weigh 3.0 g of phosphoric acid as a hydrogen bond donor and mix it with 1.5 g of the porous organosilicon quaternary ammonium salt prepared in step A and add it to a flask. Heat and stir the reaction at 90°C for 6 hours to obtain a uniform liquid under the action of hydrogen bonds. Place the uniform liquid in a drying oven at a drying temperature of 80°C. After drying for 12 hours, porous low eutectic solvent-8 is obtained.

[0132] Model oil preparation:

[0133] Dibenzothiophene (DBT) was dissolved in n-dodecane solution to prepare a DBT model oil with a sulfur content of 1000 ppm.

[0134] Desulfurization test:

[0135] 1 g of porous deep eutectic solvent-8 was added to 2 g of DBT model oil with a sulfur content of 1000 ppm, and then 15 wt% H 2 O 2 , H 2 O 2 The molar ratio of the substance to DBT was 5:1. The stirring was stopped at 60°C after 180 minutes. At this time, the porous low eutectic solvent-8 was in the lower layer and the model oil was in the upper layer. GC-FID was used to detect the DBT content in the model oil. The removal rate of the model oil was calculated to be 99.1%.

[0136] It can be seen from the test data of the above Examples 1-8 that the porous low eutectic solvent of the present invention has excellent desulfurization performance.

[0137] Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

Claims

1. Application of a porous deep eutectic solvent in fuel desulfurization, Features: The steps for fuel oil desulfurization using porous deep eutectic solvents are as follows: At room temperature, a certain amount of fuel oil and an appropriate amount of porous low eutectic solvent were weighed and added to a homemade reaction bottle, and then a certain amount of oxidant was added. o C for 5 to 360 minutes to perform deep desulfurization; after the reaction, the porous low eutectic solvent and the fuel oil are two phases, and the desulfurized fuel oil is directly precipitated to obtain the desulfurized fuel oil; the remaining porous low eutectic solvent can be recycled by stripping operation; The method for preparing the porous deep eutectic solvent comprises the following steps: Step A: preparing porous organosilicon quaternary ammonium salt as a hydrogen bond acceptor; Step B: Weigh a certain amount of phosphoric acid as a hydrogen bond donor and mix it with the porous organosilicon quaternary ammonium salt prepared in step A in a certain proportion and add it to a flask. After heating and stirring at a certain temperature for a period of time, a uniform liquid is obtained under the action of hydrogen bonds. After the uniform liquid is placed in a drying oven for a period of time, a porous low eutectic solvent is obtained. The organosilicon quaternary ammonium salt is selected from one or more of 3-(trimethoxysilyl)propyl octadecyl dimethyl quaternary ammonium salt, 3-(trimethoxysilyl)propyl dodecyl dimethyl ammonium chloride, and 3-(trimethoxysilyl)propyl trimethyl ammonium chloride.

2. The use according to claim 1, Features: In the above steps of fuel oil desulfurization: Thiophene sulfides contained in the fuel oil; The mass ratio of the fuel oil to the porous deep eutectic solvent is (1-20): (1-10); The oxidant is hydrogen peroxide, the concentration of which is 10wt% to 30wt%, and the molar ratio of the oxidant to the thiophene sulfide in the fuel oil is (1:1) to (10:1).

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