A synthesis method and a synthesis system of 2-[(tetrahydrofurfuryl)oxy]ethanol

Abstract

The application discloses a synthesis method and a synthesis system of 2-[(tetrahydrofurfuryl)oxy]ethanol and belongs to the technical field of catalytic reaction rectification. In the presence of an acidic ionic liquid catalyst, tetrahydrofurfuryl alcohol and ethylene oxide are reacted to obtain 2-[(tetrahydrofurfuryl)oxy]ethanol; the acidic ionic liquid catalyst is N-(4-sulfonic acid) butyl-imidazole sulfate. The reaction is carried out in a catalytic reaction rectification tower. The acidic ionic liquid catalyst catalyzes the synthesis of tetrahydrofurfuryl alcohol and ethylene oxide in the catalytic reaction rectification tower and separates out 2-[(tetrahydrofurfuryl)oxy]ethanol. The catalytic reaction rectification tower replaces a fixed bed reactor, efficiently promotes the forward reaction and reduces the generation of by-products. Raw materials exist in the form of liquid and gas in the process, increase the reaction contact area, speed up the reaction speed and realize the efficient preparation of the organic intermediate 2-[(tetrahydrofurfuryl)oxy]ethanol.

Description

Technical Field

[0001] This invention belongs to the field of catalytic reactive distillation technology, specifically relating to a method and system for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Organic chemical intermediates are the main carriers for the development of pharmaceuticals, pesticides, dyes, organic pigments, and photosensitive materials. Therefore, accelerating the development of the organic synthetic chemistry industry will inevitably promote the improvement of intermediate synthesis technology, product variety, and quality. 2-[(tetrahydrofurfuryl)oxy]ethanol is a colorless to pale yellow transparent liquid. Depending on the amount of ethylene oxide added during the reaction, intermediates with different properties can be obtained. It is mainly used in emulsifiers, penetrants, and wetting agents. Due to its good hydrophilic and lipophilic properties, it can also be used as a solvent in the coatings and resins industries. The traditional method for preparing 2-[(tetrahydrofurfuryl)oxy]ethanol involves reacting tetrahydrofurfuryl alcohol and ethylene oxide in a high-pressure reactor. This method has low production efficiency and certain hazards (ethylene oxide explosion). To improve the yield of 2-[(tetrahydrofurfuryl)oxy]ethanol, a suitable catalyst is essential. Currently, there are few reports on catalysts used for the synthesis of 2-[(tetrahydrofurfuryl)oxy]ethanol.

[0004] Therefore, finding a process for preparing organic intermediates that is easy to synthesize, efficiently separates, simple to operate, safe, and low in cost is of great practical significance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method and system for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol. This invention utilizes an acidic ionic liquid catalyst to synthesize and separate 2-[(tetrahydrofurfuryl)oxy]ethanol via a catalytic reactive distillation column, while simultaneously accelerating the synthesis rate of 2-[(tetrahydrofurfuryl)oxy]ethanol. It offers advantages such as wide applicability, low equipment cost, and high product purity.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A first aspect of the present invention provides a method for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol, comprising the following steps:

[0008] In the presence of an acidic ionic liquid catalyst, tetrahydrofurfuryl alcohol reacts with ethylene oxide to yield 2-[(tetrahydrofurfuryl)oxy]ethanol;

[0009] The acidic ionic liquid catalyst is N-(4-sulfonic acid)butyl-imidazolium sulfate.

[0010] In some embodiments of the present invention, the molar ratio of tetrahydrofurfuryl alcohol to ethylene oxide is 4:1, and the amount of acidic ionic liquid catalyst is 2.4-2.6 wt% of the mass of the added raw materials.

[0011] In some embodiments of the present invention, the preparation method of the acidic ionic liquid catalyst includes the following steps:

[0012] N-methylimidazolium and 1,4-butanesulfonate lactone were mixed and heated and stirred to obtain N-(4-sulfonyl)butyl-imidazolium salt;

[0013] The reaction of N-(4-sulfonyl)butyl-imidazolium salt with concentrated sulfuric acid yields the acidic ionic liquid catalyst N-(4-sulfonyl)butyl-imidazolium sulfate.

[0014] In some embodiments of the present invention, the molar ratio of N-methylimidazole to 1,4-butanesulfonate lactone is 1:1 to 1.5.

[0015] Preferably, the reaction temperature of the heating and stirring reaction is 35-45°C.

[0016] Preferably, the molar ratio of the N-(4-sulfonyl)butyl-imidazolium salt to concentrated sulfuric acid is (0.9-1.1):(0.9-1.1).

[0017] Preferably, when the N-(4-sulfonyl)butyl-imidazolium salt reacts with concentrated sulfuric acid, the reaction temperature is 35-45°C, and the reaction is stirred.

[0018] In some embodiments of the present invention, the synthesis method further includes the steps of purification, drying, washing to remove impurities, and drying after heating and stirring reaction;

[0019] Wherein, the drying is vacuum drying;

[0020] The washing process involves washing with ethyl acetate followed by vacuum drying to obtain N-(4-sulfonic acid)butyl-imidazolium salt.

[0021] A second aspect of the present invention provides a system for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol, comprising:

[0022] Tetrahydrofurfuryl alcohol storage tank, preheater, catalytic reactive distillation column, ethylene oxide storage tank, vaporization tank, protective gas storage tank, column top condenser, column bottom condenser, 2-[(tetrahydrofurfuryl)oxy]ethanol storage tank;

[0023] The catalytic reactive distillation column is divided into a reaction section and a stripping section from top to bottom; the reaction section is equipped with a liquid inlet and a gas inlet; the tetrahydrofurfuryl alcohol storage tank, preheater and liquid inlet are connected in sequence; the ethylene oxide storage tank, vaporization tank and gas inlet are connected in sequence; the light component outlet at the top of the catalytic reactive distillation column is connected to the top condenser, and the heavy component outlet at the bottom of the column is connected in sequence to the bottom condenser and the 2-[(tetrahydrofurfuryl)oxy]ethanol storage tank;

[0024] The material outlet of the protective gas storage tank is connected to the material inlet of the ethylene oxide storage tank and the gas inlet of the reaction section, respectively.

[0025] In some embodiments of the present invention, the reaction section is a 25-50 layer tray, and the acidic ionic liquid catalyst is packed using a structured catalyst packing method.

[0026] The stripping section consists of 25-50 trays or packing of corresponding height, and the packing is Westergren ring packing.

[0027] In some embodiments of the present invention, the gas outlet of the tower top condenser is connected to the material inlet of the ethylene oxide storage tank;

[0028] Alternatively, the synthesis system may also include a storage tank, with the gas outlet of the top condenser connected to the material inlet of the storage tank.

[0029] In some embodiments of the present invention, the inlet of the acidic ionic liquid catalyst is located between the tetrahydrofurfuryl alcohol storage tank and the preheater.

[0030] In some embodiments of the present invention, the top of the catalytic reactive distillation column is provided with a top explosion-proof plate.

[0031] A third aspect of the present invention provides a method for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol, using the above-described synthetic system, comprising the following steps:

[0032] Before synthesis, the catalytic reaction distillation column is purged with a protective gas to ensure that the reaction is in a protective gas environment;

[0033] Tetrahydrofurfuryl alcohol from the storage tank enters the preheater, as does the acidic ionic liquid catalyst. After being heated to 175°C or higher, both tetrahydrofurfuryl alcohol and the acidic ionic liquid catalyst enter the reaction section of the catalytic reactive distillation column through the liquid inlet. Ethylene oxide from the storage tank is vaporized in a vaporizer and then enters the reaction section of the catalytic reactive distillation column through the gas inlet. Under protective gas conditions, tetrahydrofurfuryl alcohol and ethylene oxide react in the reaction section under the catalysis of the acidic ionic liquid catalyst to obtain the product. The product then enters the bottom of the column through the stripping section, where tetrahydrofurfuryl alcohol is separated to obtain 2-[(tetrahydrofurfuryl)oxy]ethanol.

[0034] The acidic ionic liquid catalyst is N-(4-sulfonic acid)butyl-imidazolium sulfate;

[0035] The molar ratio of tetrahydrofurfuryl alcohol to ethylene oxide added to the catalytic reactive distillation column is 4:1, and the amount of catalyst used is 2.4-2.6 wt% of the added raw material mass.

[0036] The operating conditions of the catalytic reactive distillation column are as follows: operating temperature 10–200℃; operating pressure 0.1–0.5 MPa; reflux ratio 5–10; bottom temperature 180–200℃; top temperature 10–25℃.

[0037] The beneficial effects of this invention are as follows:

[0038] This invention provides a method for synthesizing the organic intermediate 2-[(tetrahydrofurfuryl)oxy]ethanol. In the presence of an acidic ionic liquid catalyst, tetrahydrofurfuryl alcohol and ethylene oxide react to generate the organic intermediate 2-[(tetrahydrofurfuryl)oxy]ethanol. The acidic ionic liquid catalyst used in this invention has high catalytic efficiency and high conversion efficiency. This invention uses a catalytic reactive distillation column instead of a traditional fixed-bed reactor, which efficiently promotes the forward reaction and reduces the generation of by-products. The raw materials can exist in both liquid and gaseous forms during the process, increasing the reaction contact area and accelerating the reaction rate. In the catalytic reactive distillation column, the acidic ionic liquid catalyst catalyzes the synthesis of the target product from tetrahydrofurfuryl alcohol and ethylene oxide. Because the catalytic reactive distillation column has a reaction section and a stripping section, the synthesis and timely separation of the target product are achieved within the column, improving the yield and purity of the target product.

[0039] The distillation system designed in this invention combines a catalytic reaction process, effectively shortening the preparation path of the target product. It achieves product synthesis and separation through a single catalytic reaction distillation column, while saving investment and operating costs. The synthesis system provided by this invention has the characteristics of wide application range, high selectivity, easy temperature control, low energy consumption, shortened reaction time, and enhanced equipment production capacity, enabling the efficient preparation of the organic intermediate 2-[(tetrahydrofurfuryl)oxy]ethanol. Attached Figure Description

[0040] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0041] Figure 1 This is a structural diagram of the synthesis system of 2-[(tetrahydrofurfuryl)oxy]ethanol in Example 1 of the present invention;

[0042] Figure 2 This is a structural diagram of the synthesis system of 2-[(tetrahydrofurfuryl)oxy]ethanol in Example 2 of the present invention;

[0043] Figure 3 for Figure 1 and Figure 2 Schematic diagram of a catalytic reaction distillation column;

[0044] Figure 4 for Figure 3 Schematic diagram of the explosion-proof plate structure at the top of the central tower.

[0045] Among them, 1-catalytic reactive distillation column, 101-reaction section, 102-stripping section, 103-reaction section packing, 104-stripping section packing, 105-packing support plate, 106-packing outlet, 107-top explosion-proof plate, 108-liquid inlet, 109-gas inlet; 2-top condenser, 3-bottom cooler, 4-2-[(tetrahydrofurfuryl)oxy]ethanol storage tank, 5-preheater, 6-vaporization tank, 7-first feed pump, 8-second feed pump, 9-tetrahydrofurfuryl alcohol storage tank, 10-ethylene oxide storage tank, 11-protective gas storage tank, 12-storage tank.

[0046] The catalytic reaction distillation column and the storage tanks for 2-[(tetrahydrofurfuryl)oxy]ethanol, tetrahydrofurfuryl alcohol, and ethylene oxide are all equipped with monitoring instruments for pressure, temperature, and liquid level.

[0047] A reboiler (not shown in the figure) is installed at the bottom of the catalytic reactive distillation column. Detailed Implementation

[0048] In view of the problems of low efficiency, poor safety and difficulty in the synthesis of 2-[(tetrahydrofurfuryl)oxy]ethanol, this invention proposes a method and system for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol.

[0049] A typical embodiment of the present invention provides a method for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol, comprising the following steps:

[0050] In the presence of an acidic ionic liquid catalyst, tetrahydrofurfuryl alcohol reacts with ethylene oxide to yield 2-[(tetrahydrofurfuryl)oxy]ethanol;

[0051] The acidic ionic liquid catalyst is N-(4-sulfonic acid)butyl-imidazolium sulfate.

[0052] This invention utilizes an acidic ionic liquid catalyst to catalyze the reaction of tetrahydrofurfuryl alcohol and ethylene oxide to obtain 2-[(tetrahydrofurfuryl)oxy]ethanol. The acidic ionic liquid catalyst has high catalytic efficiency and high conversion rate, enabling one-step synthesis of the target product, effectively shortening the preparation path of the target product, and achieving efficient preparation of the target product.

[0053] In some embodiments of this implementation, the molar ratio of tetrahydrofurfuryl alcohol to ethylene oxide is 4:1, and the amount of acidic ionic liquid catalyst is 2.4-2.6 wt% of the mass of the added raw materials, preferably 2.5 wt%.

[0054] It should be noted that the term "raw materials" refers to the added tetrahydrofurfuryl alcohol and ethylene oxide, and the amount of acidic ionic liquid catalyst is 2.4-2.6 wt% of the mass of the added raw materials, which means that the amount of acidic ionic liquid catalyst is 2.4-2.6 wt% of the total mass of the added tetrahydrofurfuryl alcohol and ethylene oxide.

[0055] In some embodiments of this implementation, the synthetic route of the acidic ionic liquid catalyst is as follows:

[0056]

[0057] The preparation method of the acidic ionic liquid catalyst includes the following steps:

[0058] N-methylimidazolium and 1,4-butanesulfonate lactone were mixed and heated and stirred to obtain N-(4-sulfonyl)butyl-imidazolium salt;

[0059] The reaction of N-(4-sulfonyl)butyl-imidazolium salt with concentrated sulfuric acid yields the acidic ionic liquid catalyst N-(4-sulfonyl)butyl-imidazolium sulfate.

[0060] In some embodiments of this implementation, the molar ratio of N-methylimidazole to 1,4-butanesulfonate lactone is 1:1 to 1.5.

[0061] In some embodiments of this implementation, the reaction temperature of the heating and stirring reaction is 35-45°C, specifically 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, etc. The heating and stirring reaction can be carried out under water bath or oil bath conditions. More preferably, the reaction is carried out under oil bath conditions at 40°C with stirring, and the reaction time is 16-24 hours.

[0062] In some embodiments of this implementation, the molar ratio of the N-(4-sulfonyl)butyl-imidazolium salt to concentrated sulfuric acid (98%) is (0.9-1.1):(0.9-1.1). Preferably, the molar ratio of the N-(4-sulfonyl)butyl-imidazolium salt to concentrated sulfuric acid (98%) is 1:1, i.e., equimolar.

[0063] It should be noted that when N-(4-sulfonyl)butyl-imidazolium salt reacts with concentrated sulfuric acid, concentrated sulfuric acid is added dropwise to N-(4-sulfonyl)butyl-imidazolium salt and mixed.

[0064] Preferably, the N-(4-sulfonic acid)butyl-imidazolium salt reacts with concentrated sulfuric acid at a temperature of 35-45°C, specifically 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, etc. The reaction is then stirred. Preferably, the reaction is carried out at 40°C with stirring for approximately 48 hours. After observing that all solid ions have dissolved, the mixture is purified and dried to obtain an acidic ionic liquid catalyst, which is a sulfonic acid-based ionic liquid.

[0065] In some embodiments of this implementation, the preparation method further includes the steps of purification, drying, washing to remove impurities, and drying after heating and stirring reaction;

[0066] Wherein, the drying is vacuum drying;

[0067] The washing process involves washing with ethyl acetate followed by vacuum drying to obtain N-(4-sulfonic acid)butyl-imidazolium salt.

[0068] It should be noted that after the heating and stirring reaction is completed, a white solid product is obtained, which is then purified and dried under vacuum. The obtained N-(4-sulfonyl)butyl-imidazolium salt solid is insoluble in organic solvents such as ethyl acetate and is extremely susceptible to moisture in air. Therefore, it can be washed repeatedly (3 to 5 times) with ethyl acetate to remove impurities, and then dried under vacuum (vacuum drying in a 60°C oven for 6 hours) to obtain N-(4-sulfonyl)butyl-imidazolium salt.

[0069] A second typical embodiment of the present invention provides a synthesis system for 2-[(tetrahydrofurfuryl)oxy]ethanol, such as... Figure 1 , Figure 2 As shown, the synthesis system includes:

[0070] 9. Tetrahydrofurfuryl alcohol storage tank; 5. Preheater; 1. Catalytic reactive distillation column; 10. Ethylene oxide storage tank; 6. Vaporization tank; 11. Protective gas storage tank; 2. Top condenser; 3. Bottom condenser; 4. 2-[(tetrahydrofurfuryl)oxy]ethanol storage tank.

[0071] The catalytic reactive distillation column 1 is divided into a reaction section 101 and a stripping section 102 from top to bottom; the reaction section 101 is provided with a liquid inlet 108 and a gas inlet 109; the tetrahydrofurfuryl alcohol storage tank 9, the preheater 5 and the liquid inlet 108 are connected in sequence; the ethylene oxide storage tank 10, the vaporization tank 6 and the gas inlet 109 are connected in sequence; the light component outlet at the top of the catalytic reactive distillation column 1 is connected to the top condenser 2, and the heavy component outlet at the bottom of the column is connected in sequence to the bottom condenser 3 and the 2-[(tetrahydrofurfuryl)oxy]ethanol storage tank 4;

[0072] The material outlet of the protective gas storage tank 11 is connected to the material inlet of the ethylene oxide storage tank 10 and the gas inlet 109 of the reaction section 101, respectively.

[0073] Ethylene oxide enters reaction section 101 under the protection of a protective gas, which reduces its explosiveness. The protective gas can be an inert gas or nitrogen, preferably nitrogen.

[0074] It should be noted that since the product 2-[(tetrahydrofurfuryl)oxy]ethanol is a heavy component and no light component is produced in the entire reaction, the catalytic reaction distillation column does not have a rectification section, but only includes a reaction section and a stripping section.

[0075] It should be noted that the term "sequential connection" refers to various devices being connected in series in the aforementioned order. For example, "tetrahydrofurfuryl alcohol storage tank 9, preheater 5 and liquid inlet 108 sequentially connected" means that the material outlet of tetrahydrofurfuryl alcohol storage tank 9 is connected to the material inlet of preheater 5, and the material outlet of preheater 5 is connected to liquid inlet 108.

[0076] The synthesis system for 2-[(tetrahydrofurfuryl)oxy]ethanol provided by this invention has the characteristics of wide application range, high selectivity, easy temperature control, low energy consumption, and enhanced equipment production capacity while shortening reaction time, and can realize the efficient preparation of organic intermediate 2-[(tetrahydrofurfuryl)oxy]ethanol.

[0077] In some embodiments of this implementation, the reaction section 101 is a 25-50 layer tray, and the acidic ionic liquid catalyst is packed using a structured catalyst packing method.

[0078] In some embodiments of this implementation, the stripping section 102 is a 25-50 tray or a packing of corresponding height, and the packing is Westerner ring packing.

[0079] In some embodiments of this implementation, the gas outlet of the top condenser 2 is connected to the material inlet of the ethylene oxide storage tank 10;

[0080] Alternatively, the synthesis system may also include a storage tank 12, wherein the gas outlet of the top condenser 2 is connected to the material inlet of the storage tank 12.

[0081] In some embodiments of this implementation, the inlet of the acidic ionic liquid catalyst is located between the tetrahydrofurfuryl alcohol storage tank 9 and the preheater 5, so that the acidic ionic liquid catalyst and tetrahydrofurfuryl alcohol are added to the reaction section 101 simultaneously. The inlet of the acidic ionic liquid catalyst can be located on the pipeline between the tetrahydrofurfuryl alcohol storage tank 9 and the preheater 5, or it can be directly connected to the material inlet of the preheater 5.

[0082] In some embodiments of this implementation, to improve the safety of the synthesis system, a top explosion-proof plate 107 is provided at the top of the catalytic reactive distillation column 1. A safety valve (not shown in the figure) is also provided at the top of the column. Valves (not shown in the figure) are provided on the feed lines for tetrahydrofurfuryl alcohol and ethylene oxide, and on the discharge line for catalytic reactive distillation column 1, for monitoring purposes.

[0083] In some embodiments of this implementation, a first feed pump 7 is provided between the tetrahydrofurfuryl alcohol storage tank 9 and the preheater 5, and a second feed pump 8 is provided between the ethylene oxide storage tank 10 and the vaporization tank 6. The feed pumps transport the raw materials to the next equipment.

[0084] In some embodiments of this implementation, a reboiler (not shown in the figure) is provided at the bottom of the catalytic reactive distillation column 1.

[0085] To enhance safety, emergency shut-off valves are installed at the feed and reboiler evaporation section of catalytic reactive distillation column 1. Unreacted ethylene oxide is collected after being condensed by the overhead condenser 2 and then returned to the ethylene oxide storage tank 10 or stored in the storage tank 12. Unreacted tetrahydrofurfuryl alcohol is heated in the reboiler to separate it from the product 2-[(tetrahydrofurfuryl)oxy]ethanol and then returned to the reaction section 101 of catalytic reactive distillation column 1 for catalytic reaction, thereby improving feedstock utilization.

[0086] A third typical embodiment of the present invention provides a method for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol, using the above-described synthesis system, comprising the following steps:

[0087] Before synthesis, the catalytic reaction distillation column is purged with a protective gas to ensure that the reaction is in a protective gas environment;

[0088] Tetrahydrofurfuryl alcohol from the storage tank enters the preheater, as does the acidic ionic liquid catalyst. After being heated to 175°C or higher, both tetrahydrofurfuryl alcohol and the acidic ionic liquid catalyst enter the reaction section of the catalytic reactive distillation column through the liquid inlet. Ethylene oxide from the storage tank is vaporized in a vaporizer and then enters the reaction section of the catalytic reactive distillation column through the gas inlet. Under protective gas conditions, tetrahydrofurfuryl alcohol and ethylene oxide react in the reaction section under the catalysis of the acidic ionic liquid catalyst to obtain the product. The product then enters the bottom of the column through the stripping section, where tetrahydrofurfuryl alcohol is separated to obtain 2-[(tetrahydrofurfuryl)oxy]ethanol.

[0089] The acidic ionic liquid catalyst is N-(4-sulfonic acid)butyl-imidazolium sulfate;

[0090] The molar ratio of tetrahydrofurfuryl alcohol and ethylene oxide added to the catalytic reactive distillation column is 4:1, and the amount of catalyst used is 2.4-2.6 wt% of the added raw material, preferably 2.5 wt%.

[0091] The operating conditions of the catalytic reactive distillation column are as follows: operating temperature 10–200℃; operating pressure 0.1–0.5 MPa; reflux ratio 5–10; bottom temperature 180–200℃; top temperature 10–25℃.

[0092] Ethylene oxide enters the reaction section under the protection of a protective gas, which reduces its explosiveness and improves safety. Preferably, the protective gas can be an inert gas or nitrogen, with nitrogen being the preferred option.

[0093] It should be noted that since the product 2-[(tetrahydrofurfuryl)oxy]ethanol is a heavy component and no light component is produced in the entire reaction, the catalytic reaction distillation column does not have a rectification section, but only includes a reaction section and a stripping section.

[0094] In the reaction section, an acidic ionic liquid catalyst catalyzes the reaction of tetrahydrofurfuryl alcohol and ethylene oxide to produce 2-[(tetrahydrofurfuryl)oxy]ethanol. The product is then fed into the bottom of the distillation column via a stripping section, where it is separated to obtain the target product. During the reaction, the synthesis and separation of the target product 2-[(tetrahydrofurfuryl)oxy]ethanol are achieved, promoting the reaction in the forward direction and accelerating the synthesis rate of 2-[(tetrahydrofurfuryl)oxy]ethanol. The synthesis method of this invention has advantages such as wide applicability, low equipment cost, and high product purity.

[0095] The synthesis method of this invention uses a catalytic reactive distillation column instead of a fixed-bed reactor, which efficiently promotes the forward reaction and reduces the generation of by-products. The raw materials exist in liquid and gaseous forms during the process, increasing the reaction contact area, accelerating the reaction rate, and achieving the efficient preparation of 2-[(tetrahydrofurfuryl)oxy]ethanol.

[0096] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0097] Example 1

[0098] A system for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol, such as Figure 1 and Figure 3 , Figure 4 As shown, it mainly includes: raw material storage tank, catalytic reaction distillation column 1, preheater 5, vaporization tank 6, condenser, and nitrogen cylinder (i.e., Figure 1The protective gas storage tank 11 is provided, and the raw material storage tank and the catalytic reactive distillation column 1 are equipped with monitoring instruments for temperature, pressure, and liquid level. There are three raw material storage tanks: a tetrahydrofurfuryl alcohol storage tank 9, an ethylene oxide storage tank 10, and a 2-[(tetrahydrofurfuryl)oxy]ethanol storage tank 4, each used to store its respective raw material. The catalytic reactive distillation column 1 has one tower, with a tower top explosion-proof plate 107 and a safety valve, and emergency shut-off valves are provided for the feed and reboiler steam sections. Since the products in the synthesis of 2-[(tetrahydrofurfuryl)oxy]ethanol of this invention are all heavy components with no light components produced, the catalytic reactive distillation column 1 does not have a rectification section, but only includes a reaction section 101 and a stripping section 102. Figure 3 As shown, the reaction section 101 is equipped with a liquid inlet 108 and a gas inlet 109, and the catalytic reactive distillation column 1 of the reaction section is equipped with reaction section packing 103. Correspondingly, a packing outlet 106 is also provided on the column wall of the reaction section 101. The position of the liquid inlet 108 on the column wall is higher than that of the gas inlet 109. The stripping section 102 consists of a packing support plate 105, stripping section packing 104, and a packing support plate 105 from top to bottom. Correspondingly, a packing outlet 106 is also provided on the column wall of the stripping section 102. The preheater 5 is used to preheat the raw material tetrahydrofurfuryl alcohol and the ionic liquid catalyst. The vaporization tank 6 is used to vaporize the raw material ethylene oxide. There are two condensers: a top condenser 2 and a bottom condenser 3.

[0099] The material outlet of the tetrahydrofurfuryl alcohol storage tank 9 is connected to the material inlet of the preheater 5 via the first feed pump 7. An acidic ionic liquid catalyst is connected between the material outlet of the tetrahydrofurfuryl alcohol storage tank 9 and the material inlet of the preheater 5. The material outlet of the preheater 5 is connected to the liquid inlet 108 of the reaction section 101. The material outlet of the ethylene oxide storage tank 10 is connected to the material inlet of the vaporization tank 6 via the second feed pump 8. After vaporization, the ethylene oxide enters the catalytic reactive distillation column 1 through the material outlet of the vaporization tank 6 and the gas inlet 109 of the reaction section 101. The gas outlet of the nitrogen cylinder is connected to both the material inlet of the ethylene oxide storage tank 10 and the gas inlet 109 of the reaction section 101. The light component outlet (i.e., gas outlet) at the top of the catalytic reactive distillation column 1 is connected to the material inlet of the top condenser 2, and the material outlet of the top condenser 2 is connected to the material inlet of the ethylene oxide storage tank 10. The heavy fraction outlet (i.e., the outlet of the bottom liquid after the liquid outlet) of the catalytic reactive distillation column 1 is connected to the material inlet of the bottom condenser 3, and the material outlet of the bottom condenser 3 is connected to the material inlet of the 2-[(tetrahydrofurfuryl)oxy]ethanol storage tank 4.

[0100] The catalytic reaction distillation column 1 is made of 316L stainless steel, the reaction section 101 uses an acidic ionic liquid catalyst, the stripping section 102 uses Sheta ring packing (5*5), and the packing in the reaction section 101 is inert packing.

[0101] The above-disclosed methods for coordinating and connecting various devices meet the requirements for the preparation of 2-[(tetrahydrofurfuryl)oxy]ethanol in a continuous manner.

[0102] The process for producing 2-[(tetrahydrofurfuryl)oxy]ethanol using the synthesis system for 2-ethanol shown in this embodiment is as follows:

[0103] Before the synthesis of 2-[(tetrahydrofurfuryl)oxy]ethanol, nitrogen gas is introduced into the column through the nitrogen cylinder and gas inlet 109 to purge the column and ensure the reaction is conducted in a nitrogen environment. Nitrogen gas is also introduced into the ethylene oxide storage tank 10 to reduce the explosiveness of ethylene oxide and improve safety.

[0104] Tetrahydrofurfuryl alcohol (THF) enters preheater 5 from THF storage tank 9 via first feed pump 7. The acidic ionic liquid catalyst also enters the preheater. After being heated to 175°C, THF and the acidic ionic liquid catalyst enter the reaction section 101 of catalytic reactive distillation column 1 via liquid inlet 108. Ethylene oxide enters vaporization tank 6 from ethylene oxide storage tank 10 via second feed pump 8. After vaporization, it enters the reaction section 101 of catalytic reactive distillation column 1 via gas inlet 109. The molar ratio of THF to ethylene oxide added to the catalytic reactive distillation column is 4:1, and the catalyst dosage is 2.5 wt% of the added feed mass.

[0105] Under nitrogen protection, tetrahydrofurfuryl alcohol and ethylene oxide react in reaction section 101 under the catalysis of an acidic ionic liquid catalyst. The reacted material enters the bottom of the column, and the reboiler is turned on to heat to 200°C. In stripping section 102, tetrahydrofurfuryl alcohol and 2-[(tetrahydrofurfuryl)oxy]ethanol are separated. Unreacted tetrahydrofurfuryl alcohol re-enters reaction section 101 to participate in the reaction, while unreacted ethylene oxide enters the ethylene oxide storage tank 11 through the top condenser 2. After separation, the product 2-[(tetrahydrofurfuryl)oxy]ethanol is cooled from the bottom of the column by the bottom condenser 3 and then enters the 2-[(tetrahydrofurfuryl)oxy]ethanol storage tank 4.

[0106] The operating conditions for catalytic reactive distillation column 1 are as follows: operating temperature 10–200℃; operating pressure 0.1–0.5 MPa; reflux ratio 5–10; bottom temperature 180–200℃; top temperature 10–25℃.

[0107] This embodiment discloses various devices, and through the coordination of these devices, 2-[(tetrahydrofurfuryl)oxy]ethanol is prepared using tetrahydrofurfuryl alcohol and ethylene oxide as raw materials. The reaction equation is as follows:

[0108]

[0109] In the following synthesis examples, the conversion rate of tetrahydrofurfuryl alcohol was:

[0110]

[0111] Example 2

[0112] A system for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol, such as Figure 2 and Figure 3 , Figure 4 As shown, the difference between this synthesis system and that of Example 1 is that it has four feedstock storage tanks: tetrahydrofurfuryl alcohol tank 9, ethylene oxide tank 10, 2-[(tetrahydrofurfuryl)oxy]ethanol tank 4, and tank 12. The material outlet of the overhead condenser 2 is connected to the material inlet of a separate tank 12 to store the light components escaping from the top of the catalytic reactive distillation column 1. The rest is the same as in Example 1.

[0113] Example 3

[0114] A method for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol includes the following steps:

[0115] (1) Preparation of acidic ionic liquid catalysts:

[0116] Under solvent-free conditions, 40 mL of N-methylimidazole and 65 mL of 1,4-butanesulfonate lactone were sequentially added to a 300 mL three-necked flask and mixed. The mixture was heated to 40 °C in an oil bath and stirred for 16 h. After the reaction was complete, a white solid product was obtained, which was then purified and dried under vacuum.

[0117] The prepared solid is insoluble in organic solvents such as ethyl acetate and is extremely susceptible to moisture in the air. Therefore, it is washed repeatedly (5 times) with ethyl acetate to remove impurities, and then placed in a 60°C oven for vacuum drying for 6 hours to obtain N-(4-sulfonyl)butyl-imidazolium salt.

[0118] The obtained solid was then added to a three-necked flask, and an equimolar amount of sulfuric acid solution (98%) was added dropwise. The mixture was stirred at 40°C for 48 hours. After observing that all the solid ions had dissolved, it was purified and dried to obtain a sulfonic acid ionic liquid catalyst with a yield of 99.46%.

[0119] The obtained ionic liquid catalyst was analyzed using Fourier transform nuclear magnetic resonance (NMR) spectroscopy to determine its 1H and 13C NMR spectra, verifying the catalyst's structural composition. The solvent used was D₂O. The NMR (1H NMR, δ, ppm) results were: 1.273 (2H), 1.581 (2H), 2.483 (2H), 3.431 (3H), 3.789 (2H), 4.802 (H), 6.076 (H), 7.032 (H), 8.244 (2H); the NMR (13C NMR, δ, ppm) results were: 21.287, 28.286, 36.402, 49.931, 121.751, 135.607.

[0120] (2) Catalytic reactive distillation process using ionic liquid catalysts

[0121] 2-[(tetrahydrofurfuryl)oxy]ethanol was synthesized using the synthesis system of 2-[(tetrahydrofurfuryl)oxy]ethanol in Example 1. Specific operating parameters were as follows: a catalytic reactive distillation column with a diameter of 1.8 m, 35 catalytic reactive distillation trays in the catalytic reaction section, and 2 m of packing in the stripping section. Operating conditions were: operating pressure of 0.2 MPa, top temperature of 15.02 °C, bottom temperature of 201.56 °C, reflux ratio of 6, and catalytic reaction time of 24 h.

[0122] The obtained product, 2-[(tetrahydrofurfuryl)oxy]ethanol, was determined using Fourier transform nuclear magnetic resonance spectroscopy. 1 H NMR, 13 C NMR, with D₂O as the solvent. Its NMR ( 1 The results of H NMR (δ, ppm) were: 1.871 (2H), 1.932 (2H), 3.361 (2H), 3.431 (2H), 3.564 (2H), 3.651 (H), 3.802 (2H), 4.071 (H); NMR (δ, ppm) 13 The CNMR (δ, ppm) results were: 25.921, 27.712, 61.354, 67.931, 71.164, 75.445, 86.216.

[0123] Comparative Example 1

[0124] A method for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol, compared with Example 2, does not include the addition of an ionic liquid catalyst. Specific operating parameters are as follows: a catalytic reactive distillation column with a diameter of 1.8 m, 35 catalytic reactive distillation trays in the catalytic reaction section, and 2 m of packing in the stripping section. Operating conditions are: operating pressure of 0.2 MPa, top temperature of 15.32 °C, bottom temperature of 200.23 °C, reflux ratio of 6, and catalytic reaction time of 24 h.

[0125] Example 4

[0126] A method for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol includes the following steps:

[0127] (1) Preparation of ionic liquid catalysts

[0128] Under solvent-free conditions, 40 mL of N-methylimidazole and 65 mL of 1,4-butanesulfonate lactone were sequentially added to a 300 mL three-necked flask and mixed. The mixture was heated to 40 °C in an oil bath and stirred for 20 h. After the reaction was complete, a white solid product was obtained, which was then purified and dried under vacuum.

[0129] The prepared solid is insoluble in organic solvents such as ethyl acetate and is extremely susceptible to moisture in the air. Therefore, it is washed repeatedly (5 times) with ethyl acetate to remove impurities, and then placed in a 60°C oven for vacuum drying for 6 hours to obtain N-(4-sulfonyl)butyl-imidazolium salt.

[0130] The obtained solid was then added to a three-necked flask, and an equimolar amount of sulfuric acid solution (98%) was added dropwise. The mixture was stirred at 40°C for 48 hours. After observing that all the solid ions had dissolved, the mixture was purified and dried to obtain a sulfonic acid ionic liquid catalyst with a yield of 99.67%.

[0131] (2) Catalytic reactive distillation process using ionic liquid catalysts

[0132] 2-[(tetrahydrofurfuryl)oxy]ethanol was synthesized using the synthesis system of 2-[(tetrahydrofurfuryl)oxy]ethanol in Example 1. Specific operating parameters were as follows: a catalytic reactive distillation column with a diameter of 1.8 m, 35 catalytic reactive distillation trays in the catalytic reaction section, and 2 m of packing in the stripping section. Operating conditions were: operating pressure of 0.2 MPa, top temperature of 15.56 °C, bottom temperature of 200.74 °C, reflux ratio of 6, and catalytic reaction time of 24 h.

[0133] Example 5

[0134] A method for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol includes the following steps:

[0135] (1) Preparation of ionic liquid catalysts

[0136] Under solvent-free conditions, 40 mL of N-methylimidazole and 65 mL of 1,4-butanesulfonate lactone were sequentially added to a 300 mL three-necked flask and mixed. The mixture was heated to 40 °C in an oil bath and stirred for 24 h. After the reaction was complete, a white solid product was obtained, which was then purified and dried under vacuum.

[0137] The prepared solid is insoluble in organic solvents such as ethyl acetate and is extremely susceptible to moisture in the air. Therefore, it is washed repeatedly (3 to 5 times) with ethyl acetate to remove impurities, and then placed in a 60°C oven for vacuum drying for 6 hours to obtain N-(4-sulfonic acid)butyl-imidazolium salt.

[0138] The obtained solid was then added to a three-necked flask, and an equimolar amount of sulfuric acid solution (98%) was added dropwise. The mixture was stirred at 40°C for 48 hours. After observing that all the solid ions had dissolved, it was purified and dried to obtain a sulfonic acid ionic liquid catalyst with a yield of 99.76%.

[0139] (2) Catalytic reactive distillation process using ionic liquid catalysts

[0140] 2-[(tetrahydrofurfuryl)oxy]ethanol was synthesized using the synthesis system of 2-[(tetrahydrofurfuryl)oxy]ethanol in Example 1. Specific operating parameters were as follows: a catalytic reactive distillation column with a diameter of 1.8 m, 35 catalytic reactive distillation trays in the catalytic reaction section, and 2 m of packing in the stripping section. Operating conditions were: operating pressure of 0.2 MPa, top temperature of 15.21 °C, bottom temperature of 200.23 °C, reflux ratio of 6, and catalytic reaction time of 24 h.

[0141] After the synthesis systems of Examples 3-5 and Comparative Example 1 were running normally, the experimental results were obtained as shown in Table 2.

[0142] Table 2. Test results of the synthesis systems of Examples 3-5 and Comparative Example 1.

[0143] sample Catalyst yield (%) Raw material conversion rate (%) Product purity (%) Example 3 99.46 98.71 97.00 Comparative Example 1 - 89.56 88.32 Example 4 99.67 98.60 97.34 Example 5 99.76 99.87 98.27

[0144] As shown in Table 2, and as described above, the catalytic reactive distillation process of this invention can effectively improve the raw material conversion rate for preparing the organic intermediate 2-[(tetrahydrofurfuryl)oxy]ethanol, as shown in Comparative Example 1. With the extension of reaction time during the preparation of the acidic ionic liquid catalyst, the raw material conversion rate during distillation increases, as shown in Examples 4 and 5.

[0145] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol, characterized in that, Includes the following steps: In the presence of an acidic ionic liquid catalyst, tetrahydrofurfuryl alcohol reacts with ethylene oxide to yield 2-[(tetrahydrofurfuryl)oxy]ethanol; The acidic ionic liquid catalyst is N-(4-sulfonic acid)butyl-imidazolium sulfate; The molar ratio of tetrahydrofurfuryl alcohol to ethylene oxide is 4:1, and the amount of acidic ionic liquid catalyst is 2.4-2.6 wt% of the added raw materials.

2. The synthesis method according to claim 1, characterized in that, The preparation method of the acidic ionic liquid catalyst includes the following steps: N-methylimidazolium and 1,4-butanesulfonate lactone were mixed and heated and stirred to obtain N-(4-sulfonyl)butyl-imidazolium salt; The reaction of N-(4-sulfonyl)butyl-imidazolium salt with concentrated sulfuric acid yields the acidic ionic liquid catalyst N-(4-sulfonyl)butyl-imidazolium sulfate.

3. The synthesis method as described in claim 2, characterized in that, The molar ratio of N-methylimidazolium to 1,4-butanesulfonate lactone is 1:1 to 1.5; The reaction temperature for the heating and stirring reaction is 35-45℃; The molar ratio of the N-(4-sulfonic acid)butyl-imidazolium salt to concentrated sulfuric acid is (0.9-1.1):(0.9-1.1). When the N-(4-sulfonyl)butyl-imidazolium salt reacts with concentrated sulfuric acid, the reaction temperature is 35-45℃, and the reaction is stirred.

4. The synthesis method according to claim 2, characterized in that, The synthesis method also includes the steps of purification, drying, washing to remove impurities and drying after heating and stirring reaction; Wherein, the drying is vacuum drying; The washing process involves washing with ethyl acetate followed by vacuum drying to obtain N-(4-sulfonic acid)butyl-imidazolium salt.

5. A system for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol, characterized in that, include: Tetrahydrofurfuryl alcohol storage tank, preheater, catalytic reactive distillation column, ethylene oxide storage tank, vaporization tank, protective gas storage tank, column top condenser, column bottom condenser, 2-[(tetrahydrofurfuryl)oxy]ethanol storage tank; The catalytic reactive distillation column is divided into a reaction section and a stripping section from top to bottom; the reaction section is equipped with a liquid inlet and a gas inlet; the tetrahydrofurfuryl alcohol storage tank, preheater and liquid inlet are connected in sequence; the ethylene oxide storage tank, vaporization tank and gas inlet are connected in sequence; the light component outlet at the top of the catalytic reactive distillation column is connected to the top condenser, and the heavy component outlet at the bottom of the column is connected in sequence to the bottom condenser and the 2-[(tetrahydrofurfuryl)oxy]ethanol storage tank; The liquid inlet is positioned higher than the gas inlet. The material outlet of the protective gas storage tank is connected to the material inlet of the ethylene oxide storage tank and the gas inlet of the reaction section, respectively.

6. The synthesis system as described in claim 5, characterized in that, The reaction section consists of 25-50 layers of trays, and the acidic ionic liquid catalyst is packed using a structured catalyst packing method. The stripping section consists of 25-50 trays or packing of corresponding height, and the packing is Westergren ring packing.

7. The synthesis system as described in claim 5, characterized in that, The gas outlet of the condenser at the top of the tower is connected to the material inlet of the ethylene oxide storage tank. Alternatively, the synthesis system may also include a storage tank, with the gas outlet of the top condenser connected to the material inlet of the storage tank.

8. The synthesis system as described in claim 5, characterized in that, The inlet of the acidic ionic liquid catalyst is located between the tetrahydrofurfuryl alcohol storage tank and the preheater; The catalytic reaction distillation column is equipped with a top explosion-proof plate.

9. A method for synthesizing 2-[(tetrahydrofurfuryl)oxy]ethanol, characterized in that, The synthesis system described in any one of claims 5-8 comprises the following steps: Before synthesis, the catalytic reaction distillation column is purged with a protective gas to ensure that the reaction is in a protective gas environment; Tetrahydrofurfuryl alcohol from the storage tank enters the preheater, as does the acidic ionic liquid catalyst. After being heated to 175°C or higher, both tetrahydrofurfuryl alcohol and the acidic ionic liquid catalyst enter the reaction section of the catalytic reactive distillation column through the liquid inlet. Ethylene oxide from the storage tank is vaporized in a vaporizer and then enters the reaction section of the catalytic reactive distillation column through the gas inlet. Under protective gas conditions, tetrahydrofurfuryl alcohol and ethylene oxide react in the reaction section under the catalysis of the acidic ionic liquid catalyst to obtain the product. The product then enters the bottom of the column through the stripping section, where tetrahydrofurfuryl alcohol is separated to obtain 2-[(tetrahydrofurfuryl)oxy]ethanol. The acidic ionic liquid catalyst is N-(4-sulfonic acid)butyl-imidazolium sulfate; The molar ratio of tetrahydrofurfuryl alcohol to ethylene oxide added to the catalytic reactive distillation column is 4:1, and the amount of catalyst used is 2.4-2.6 wt% of the added raw material mass. The operating conditions of the catalytic reaction distillation column are as follows: operating temperature 10~200℃; operating pressure 0.1~0.5 MPa; reflux ratio 5~10; bottom temperature 180~200℃; top temperature 10~25℃.

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