Method for synthesizing 2-imidazolidinone and used sulfonic acid functionalized ionic liquid catalyst

Abstract

The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of 2-imidazolidinone and a catalyst used in the preparation method. The invention discloses a preparation method of a sulfonic acid functionalized ionic liquid catalyst. The preparation method comprises the following steps: (1) synthesis of a PMO carrier; (2) sulfonic acid functionalization: preparing a sulfonic acid functionalized material SMO-SO3H by using a PMO carrier; and (3) immobilizing and activating the ionic liquid to obtain the sulfonic acid functionalized ionic liquid catalyst (SMO-IL). The invention also discloses a method for efficiently and greenly preparing 2-imidazolidinone by taking ethylene carbonate and urea as raw materials under the action of the self-made catalyst.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, specifically relating to a method for the efficient and green preparation of 2-imidazolidineone using ethylene carbonate and urea as raw materials and under the action of a self-made catalyst. Background Technology

[0002] 2-Imidazolidinones are important nitrogen-containing heterocyclic compounds and chemical intermediates with wide applications in pharmaceuticals, pesticides, dyes, and polymer materials. Currently, the industrial and laboratory synthesis of these compounds mainly relies on several traditional methods; however, these methods all have significant limitations. For example, the cyclization method of phosgene or its equivalents (such as carbonyl diimidazole) with ethylenediamine, although yielding high yields, poses a serious threat to production safety and the environment due to the highly toxic and corrosive nature of the raw materials, and no longer meets the requirements of modern green chemistry. Another common route involves the direct high-temperature condensation of ethylenediamine with urea, including a one-step cyclization condensation method. While this method has lower raw material costs, the harsh reaction conditions and numerous side reactions result in unsatisfactory product purity and yield. These problems greatly restrict its efficient and clean production.

[0003] Besides the methods mentioned above, other synthetic routes also have their shortcomings. Routes using precursors such as N-aminoethylurea for intramolecular cyclization suffer from lengthy synthetic steps and poor overall atom economy, limiting their industrial economic value. While some catalytic carbonylation-based methods, such as the oxidative cyclization of ethylenediamine with carbon monoxide using noble metal catalysts, offer another route, they face challenges such as high catalyst costs and the risks associated with operating under high pressure and toxic gases, thus increasing the difficulty of equipment investment and safe production.

[0004] In summary, existing technologies for synthesizing 2-imidazolidineones suffer from drawbacks such as high toxicity of raw materials, harsh reaction conditions, high catalyst costs, poor product quality, and lengthy process routes. While improved methods, such as using ethylenediamine and bis(trichloromethyl) carbonate as raw materials, phase-transfer catalysts, and ionic liquid catalytic systems, can achieve milder reaction conditions, higher yields, and lower costs, the high toxicity of raw materials remains a concern. Phase-transfer catalysts are typically quaternary ammonium salts, such as tetrabutylammonium bromide, and ionic liquid catalytic systems include 1-butyl-3-methylimidazolium chloride zincate or sulfonic acid-functionalized imidazolium ionic liquids (such as 1-propylsulfonic acid-3-methylimidazolium phosphate dihydrogen phosphate). Therefore, developing a novel synthetic route that balances raw material safety, mild reaction conditions, controllable costs, environmental friendliness, and high-quality products is a pressing technical challenge in this field, and is of great significance for promoting the green development of related downstream industries. Summary of the Invention

[0005] The problem to be solved by the present invention is to provide an environmentally friendly method for synthesizing 2-imidazolidineone and the sulfonic acid functionalized ionic liquid catalyst used therein.

[0006] To address the aforementioned technical problems, this invention first provides a method for preparing a sulfonic acid-functionalized ionic liquid catalyst (i.e., a sulfonic acid-functionalized mesoporous organosilica-supported ionic liquid catalyst, SMO-IL), comprising the following steps:

[0007] (1) Synthesis of PMO vector:

[0008] (2) Sulfonic acid functionalization:

[0009] SMO-SO3H, a sulfonic acid-functionalized material, was prepared using a PMO carrier.

[0010] (3) Ionic liquid immobilization and activation:

[0011] The sulfonic acid functionalized material SMO-SO3H was reacted with 1-aminopropyl-3-methylimidazolium bromide ([APMIm]Br) to obtain a sulfonic acid functionalized ionic liquid catalyst (SMO-IL).

[0012] An improvement to the preparation method of the sulfonic acid functionalized ionic liquid catalyst of the present invention:

[0013] (1) Synthesis of PMO vector:

[0014] Template agent P123 was dissolved in hydrochloric acid aqueous solution, and tetraethyl orthosilicate (TEOS) and 1,2-bis(triethoxysilyl)ethane (BTEE) were added. The mixture was first stirred at 40±5℃ for 24±1 hours, and then statically crystallized at 100±10℃ for 48±2 hours. After washing, drying and calcination, PMO support was obtained.

[0015] The mass ratio of the template agent P123 to tetraethyl orthosilicate (TEOS) is 1:2.05~2.15 (preferably 1:2.08), and the mass ratio of tetraethyl orthosilicate (TEOS) to 1,2-bis(triethoxysilyl)ethane (BTEE) is 1:1.1~1.2 (preferably 1:1.125).

[0016] Instructions: First, slowly add tetraethyl orthosilicate (TEOS) over approximately 20-40 minutes, then slowly add 1,2-bis(triethoxysilyl)ethane (BTEE) over approximately 20-40 minutes.

[0017] (2) Sulfonic acid functionalization:

[0018] The PMO carrier was placed in a low-temperature plasma reactor. After the system was evacuated to 10±5 Pa, a mixture of sulfur dioxide (SO2) and inert gas was introduced, and the pressure was maintained at 50±5 Pa. The PMO carrier was subjected to plasma treatment for 20 to 60 minutes (preferably 20 to 40 minutes) under radio frequency conditions. The result was named the plasma-treated product. The volume ratio of sulfur dioxide (SO2) to argon (Ar) in the mixed gas was 1:2 to 7 (preferably 1:4).

[0019] Note: In this process, plasma-activated SO2 species interact with the silanol groups and framework on the carrier surface, initially introducing sulfur-containing species;

[0020] The plasma-treated material was then transferred to a tube furnace and heat-treated at 250–350°C for 2 ± 0.2 hours in an oxygen atmosphere (so that the sulfur-containing species on the surface are fully oxidized to stable sulfonic acid groups -SO3H); after cooling to room temperature, SMO-SO3H (sulfonic acid functionalized material) was obtained.

[0021] Note: The oxygen flow rate per minute is 2-3% of the tubular furnace volume (i.e., when the tubular furnace volume is 2L, the oxygen flow rate is 40-60mL / min).

[0022] (3) Ionic liquid immobilization and activation:

[0023] SMO-SO3H and 1-aminopropyl-3-methylimidazolium bromide ([APMIm]Br) were stirred in a solvent for 3-5 hours (at room temperature); the mass ratio of SMO-SO3H to 1-aminopropyl-3-methylimidazolium bromide was 1:1.2-1.3 (preferably 1:1.25).

[0024] The solid was then filtered, and the obtained solid was first subjected to Soxhlet extraction in the solvent (at reflux temperature), and then soaked in a sulfuric acid solution with a concentration of (1±0.2) mol / L for ion exchange; after washing with water and drying, the sulfonic acid functionalized ionic liquid catalyst (SMO-IL) was obtained.

[0025] As a further improvement to the preparation method of the sulfonic acid functionalized ionic liquid catalyst of the present invention, in step (1):

[0026] The concentration of the hydrochloric acid aqueous solution is (1.6±0.2) mol / L; the template agent P123: hydrochloric acid aqueous solution = 1g / 35~40mL.

[0027] As a further improvement to the preparation method of the sulfonic acid functionalized ionic liquid catalyst of the present invention, in step (1):

[0028] The washing process involves thorough washing with deionized water and anhydrous ethanol.

[0029] Drying was performed at 80±10℃ under vacuum for 12±1 hours;

[0030] The calcination was carried out at 550±30℃ for 6±0.5 hours.

[0031] As a further improvement to the preparation method of the sulfonic acid functionalized ionic liquid catalyst of the present invention, in step (2): the radio frequency power is 50 ~ 130 W (preferably 70 ~ 130 W).

[0032] In this invention, 2±0.5g of PMO carrier corresponds to a radio frequency power of 50~130W (preferably 70~130W).

[0033] As a further improvement to the preparation method of the sulfonic acid functionalized ionic liquid catalyst of the present invention, in step (2): the inert gas is argon (Ar).

[0034] As a further improvement to the preparation method of the sulfonic acid functionalized ionic liquid catalyst of the present invention, in step (3):

[0035] The solvent used in the reaction is acetonitrile. Generally, 100±20 mL of acetonitrile is used for every 1~3g of SMO-SO3H.

[0036] Acetonitrile Soxhlet extraction was used, and the extraction time was 22-26 hours. Generally, 100±20 mL of acetonitrile was used for every 1-3 g of SMO-SO3H during Soxhlet extraction.

[0037] The ion exchange time in sulfuric acid solution is 10~14h; generally, 1~3g of SMO-SO3H is prepared with 100±20 mL of sulfuric acid solution.

[0038] Drying was performed under vacuum at 80±10℃ for 12±1 hours.

[0039] The present invention also provides a method for synthesizing 2-imidazolidineone, wherein a sulfonic acid functionalized ionic liquid catalyst is prepared by any of the above methods;

[0040] Using urea and ethylene carbonate as raw materials, the reaction is carried out in the presence of a sulfonic acid functionalized ionic liquid catalyst (SMO-IL) under the protection of an inert gas (including nitrogen) at a reaction temperature of 120~180℃ (preferably 140~160℃) for 2~10 hours (preferably 4~6 hours). After the reaction is completed, the sulfonic acid functionalized ionic liquid catalyst (SMO-IL) is recovered by hot filtration. The filtrate (reaction solution) obtained by filtration is post-treated to obtain 2-imidazolidineone.

[0041] The molar ratio of urea to ethylene carbonate is 1:0.8~1.8 (preferably 1:1.0~1.5).

[0042] The amount of the sulfonic acid functionalized ionic liquid catalyst (SMO-IL) used is 1% to 5% of the urea quality.

[0043] That is, the present invention also provides the application of the sulfonic acid-functionalized mesoporous organosilica supported ionic liquid catalyst (SMO-IL) prepared by the present invention in the catalytic synthesis of 2-imidazolidineone.

[0044] As an improvement to the method for synthesizing 2-imidazolidineone of the present invention: after the reaction is completed, the mixture is cooled to 60±10℃ for hot filtration, and the sulfonic acid functionalized ionic liquid catalyst recovered by hot water at 60±10℃ is washed. The combined solution obtained by combining the washing liquid and the filtrate is then subjected to post-treatment.

[0045] As an improvement to the method for synthesizing 2-imidazolidineone of the present invention, the post-treatment is as follows: the filtrate / combined liquid is first subjected to vacuum distillation to recover the by-product ethylene glycol (pressure of about -0.095 MPa, distillation temperature of about 100°C), and the residue after vacuum distillation is recrystallized with a mixture of ethanol / water to obtain 2-imidazolidineone (white flaky crystals).

[0046] A mixture of ethanol and water, with a volume ratio of ethanol:water = 1:(1±0.1).

[0047] The beneficial effects of this invention are:

[0048] 1. Innovation and Synergistic Effect of Novel Heterogeneous Catalyst (SMO-IL) Design: This invention innovatively constructs a sulfonic acid group (-SO3H) and an immobilized ionic liquid (1-aminopropyl-3-methylimidazolium bromide ([APMIm]Br) ionic liquid) within the pores of a hydrophobic PMO support. These two types of bronsted acidic sites can produce a synergistic effect, forming a more acidic and stable catalytic microenvironment, whose catalytic activity surpasses that of any single component.

[0049] 2. Excellent catalytic performance: This heterogeneous catalyst (SMO-IL) possesses both a high specific surface area (600 m²) and excellent catalytic performance. 2 The ordered mesoporous structure ( / g) facilitates mass transfer. In the synthesis of 2-imidazolidineones, it exhibits high catalytic efficiency, with yields exceeding 97% and product purity reaching over 99.7%. As shown in Example 1, the yield reached 97.8%, and the purity was 99.8%.

[0050] 3. Outstanding stability and recyclability: The catalyst (SMO-IL) is immobilized through covalent bonds and strong electrostatic interactions, making it difficult for the active components to be lost. Experiments show that the catalyst (SMO-IL) can be recovered through simple filtration, and its activity does not decrease significantly after being recycled at least 5 times, far exceeding the cycle life of homogeneous catalysts, thus greatly reducing production costs.

[0051] 4. Green and simplified process: Heterogeneous catalysis technology has shown high efficiency in industrial wastewater treatment, making the separation of catalysts after reaction extremely simple (no liquid-liquid extraction required). The entire process has high atom economy and produces less waste, making it a clean, efficient and highly industrializable new technology route.

[0052] In summary, this invention first provides a novel, efficient, and stable heterogeneous catalyst for the synthesis of 2-imidazolium ketones from urea and ethylene carbonate. The method for synthesizing 2-imidazolium ketones using this catalyst is carried out under mild conditions, yields high output and excellent product purity, is environmentally friendly, and is easily scaled up industrially. Detailed Implementation

[0053] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0054] Catalyst Example 1: Preparation of SMO-IL Catalyst

[0055] 1) Synthesis of PMO vector:

[0056] In a 250 mL three-necked flask, accurately weigh 4.0 g of triblock copolymer P123 (template agent P123), and then add 150 mL of pre-prepared 1.6 mol / L hydrochloric acid aqueous solution. Place the flask in a 40°C constant temperature water bath and stir continuously with mechanical stirring (500 rpm) until the solution is clear and transparent (at which point the template agent P123 is completely dissolved). While stirring continuously, slowly add 8.32 g of tetraethyl orthosilicate (TEOS) and slowly add 9.36 g of 1,2-bis(triethoxysilyl)ethane (BTEE) sequentially (addition time approximately 0.5 h) using a pipette. After the addition is complete, continue stirring the reaction mixture at a constant speed at 40°C for 24 hours. Transfer the above reaction solution to a stainless steel high-pressure reactor lined with polytetrafluoroethylene and statically crystallize at 100°C and atmospheric pressure for 48 hours. After crystallization, the reactor was allowed to cool naturally to room temperature in an oven before being opened. The white solid product was then collected by vacuum filtration, followed by thorough washing with deionized water and anhydrous ethanol (washing until pH neutral), and finally vacuum dried at 80°C for 12 hours. The dried powder was then calcined in a muffle furnace at 550°C for 6 hours to completely remove the P123 template agent, yielding the PMO support (approximately 5.8 g).

[0057] 2). Sulfonic acid functionalization:

[0058] The 2.0 g PMO support prepared in step 1) was placed in a low-temperature plasma reactor. After evacuating the reactor to 10 Pa, a mixed gas of sulfur dioxide (SO2) and argon (Ar) (volume ratio 1:4) was introduced to maintain the reactor pressure at 50 Pa. The PMO support was subjected to plasma treatment for 30 minutes at a radio frequency power of 100 W corresponding to the low-temperature plasma reactor. During this process, the plasma-activated SO2 species interacted with the silanol groups and framework on the support surface, initially introducing sulfur-containing species.

[0059] Subsequently, the plasma-treated product was transferred to a tube furnace (2 L volume) and heat-treated at 300°C for 2 hours in an oxygen atmosphere (flow rate 50 mL / min) to fully oxidize the sulfur-containing species on the surface into stable sulfonic acid groups (-SO3H). After cooling to room temperature, the sulfonic acid functionalized material, denoted as SMO-SO3H, with a mass of approximately 2.15 g, was obtained.

[0060] 3). Ionic liquid immobilization and activation:

[0061] At room temperature, 2.0 g of SMO-SO3H and 2.5 g of 1-aminopropyl-3-methylimidazolium bromide ([APMIm]Br) ionic liquid were stirred in 100 mL of acetonitrile for 4 hours. After filtration, the resulting solid was extracted with 100 mL of acetonitrile using a Soxhlet extractor for 24 hours, with reflux circulation 6-8 times per hour and a water bath temperature of approximately 85 °C.

[0062] The solid obtained after Soxhlet extraction with acetonitrile was soaked in 100 mL of 1 mol / L sulfuric acid for 12 hours for ion exchange. After filtration, it was washed with deionized water until neutral and dried under vacuum at 80°C for 12 h to obtain 2.45 g of the final catalyst SMO-IL.

[0063] Catalyst Example 2-1: Compared with Catalyst Example 1, only the mixed gas in step 2) of plasma treatment was changed to SO2 / Ar = 1:2 (volume ratio), otherwise it was the same as Catalyst Example 1. The resulting catalyst is designated as SMO-IL-G1.

[0064] Catalyst Example 2-2: Compared with Catalyst Example 1, only the mixed gas in step 2) of plasma treatment was changed to SO2 / Ar = 1:7 (volume ratio), otherwise it was the same as Catalyst Example 1. The resulting catalyst is designated as SMO-IL-G2.

[0065] Catalyst Comparative Example 1-1: Compared with Catalyst Example 1, only the mixed gas in step 2) of plasma treatment was changed to use only pure SO2 gas; the rest was the same as Catalyst Example 1. The resulting catalyst was designated SMO-IL-GD1.

[0066] Catalyst Comparative Examples 1-2: Compared to Catalyst Example 1, only the mixed gas in step 2) of the plasma treatment was changed to use only pure argon (Ar), without SO2; otherwise, it was the same as Catalyst Example 1. The resulting catalyst was designated SMO-IL-GD2.

[0067] Catalyst Example 3-1: Compared with Catalyst Example 1, only the radio frequency power in step 2) was adjusted to 50 W, and the rest was the same as Catalyst Example 1. The resulting catalyst is denoted as SMO-IL-P1.

[0068] Catalyst Example 3-2: Compared with Catalyst Example 1, only the radio frequency power in step 2) was adjusted to 70 W, and the rest was the same as Catalyst Example 1. The resulting catalyst is denoted as SMO-IL-P2.

[0069] Catalyst Example 3-3: Compared with Catalyst Example 1, only the radio frequency power in step 2) was adjusted to 130 W, and the rest was the same as Catalyst Example 1. The resulting catalyst is denoted as SMO-IL-P3.

[0070] Catalyst Examples 3-4: Compared to Catalyst Example 1, only the radio frequency power in step 2) was adjusted to 180 W; the rest was the same as Catalyst Example 1. The resulting catalyst was designated SMO-IL-P4.

[0071] Catalyst Example 4-1: Compared with Catalyst Example 1, only the plasma treatment time in step 2) was adjusted to 20 minutes, otherwise it was the same as Catalyst Example 1. The resulting catalyst is designated as SMO-IL-T1.

[0072] Catalyst Example 4-2: Compared with Catalyst Example 1, only the plasma treatment time in step 2) was adjusted to 60 minutes; the rest was the same as Catalyst Example 1. The resulting catalyst was designated SMO-IL-T2.

[0073] Catalyst Example 5-1: Compared with Catalyst Example 1, only the subsequent heat treatment oxidation temperature in step 2) was adjusted to 350°C, otherwise it was the same as Catalyst Example 1. The resulting catalyst was designated SMO-IL-HT1.

[0074] Catalyst Example 5-2: Compared with Catalyst Example 1, only the subsequent heat treatment oxidation temperature in step 2) was adjusted to 250°C, otherwise it was the same as Catalyst Example 1. The resulting catalyst was designated SMO-IL-HT2.

[0075] Example 1: Synthesis of 2-Imidazolidinone

[0076] In a 250 mL high-pressure reactor, 1.0 mol of urea (approximately 60.06 g), 1.25 mol of ethylene carbonate (approximately 110.09 g), and the SMO-IL catalyst prepared in Example 1 (1.8 g, accounting for 3% of the urea mass) were added. The reactor was sealed and purged with nitrogen three times, followed by stirring at 140 °C for 5 hours. After the reaction was completed, the system was cooled to approximately 60 °C, and the solid catalyst was separated from the reaction liquid while still hot using a sintered filter. The filtered solid catalyst was washed with a small amount of hot water (3 × 50 ml, at 60 °C) to remove residual reactants and products, and the washing liquid was combined with the filtrate (reaction liquid).

[0077] The combined solution was first subjected to vacuum distillation (pressure -0.095 MPa, distillation temperature 100℃), and the residue was recrystallized from 150 mL of ethanol-water (volume ratio 1:1, 150 mL) to obtain 84.2 g of white flaky crystals of 2-imidazolidineone. Yield: 97.8%. HPLC purity: 99.8%.

[0078] Note: Using the method of the present invention, the result was confirmed by conventional GC-MS to be 2-imidazolidineone.

[0079] Example 2 series: The catalyst in Example 1, the SMO-IL catalyst prepared in Example 1, was replaced with the catalysts described in Table 1, and the rest was the same as in Example 1. The yield and purity of the obtained 2-imidazolidineone are shown in Table 1 below.

[0080] Table 1

[0081] Catalysts used <![CDATA[Plasma gas (SO2:Ar)]]> Radio frequency power (W) Processing time (minutes) Heat treatment temperature (°C) 2-Imidazolidinone yield (%) HPLC purity (%) Catalyst Example 1 1:4 100 30 300 97.8 99.8 Catalyst Example 2-1 1:2 100 30 300 96.8 99.5 Catalyst Example 2-2 1:7 100 30 300 95.0 99.3 Catalyst Comparative Example 1-1 1:0 (pure SO2) 100 30 300 90.2 98.5 Catalyst Comparative Examples 1-2 0:1 (pure Ar) 100 30 300 16.5 86.0 Catalyst Example 3-1 1:4 50 30 300 92.5 98.8 Catalyst Example 3-2 1:4 70 30 300 96.0 99.4 Catalyst Examples 3-3 1:4 130 30 300 95.5 99.2 Catalyst Examples 3-4 1:4 180 30 300 88.3 97.9 Catalyst Example 4-1 1:4 100 20 300 96.9 99.5 Catalyst Example 4-2 1:4 100 60 300 93.1 98.7 Catalyst Example 5-1 1:4 100 30 350 97.2 99.6 Catalyst Example 5-2 1:4 100 30 250 94.5 99.0

[0082] Yield of 2-imidazolidineone = Actual yield of 2-imidazolidineone / Theoretical yield × 100%.

[0083] Example 3-1: Compared to Example 1, the following changes were made:

[0084] The molar ratio of urea to ethylene carbonate was adjusted to 1:1.0. That is, the amount of urea remained constant at 1.0 mol, while the amount of ethylene carbonate was adjusted to 1.0 mol. The rest was the same as in Example 1.

[0085] Example 3-2: Compared to Example 1, the following changes were made:

[0086] The molar ratio of urea to ethylene carbonate was adjusted to 1:1.5. That is, the amount of urea remained constant at 1.0 mol, while the amount of ethylene carbonate was adjusted to 1.5 mol. The rest was the same as in Example 1.

[0087] Comparative Example 1-1: The following changes were made compared to Example 1:

[0088] The molar ratio of urea to ethylene carbonate was adjusted to 1:0.8. That is, the amount of urea remained unchanged at 1.0 mol, while the amount of ethylene carbonate was adjusted to 0.8 mol. The rest was the same as in Example 1.

[0089] Comparative Examples 1-2: The following changes were made compared to Example 1:

[0090] The molar ratio of urea to ethylene carbonate was adjusted to 1:1.8. That is, the amount of urea used remained unchanged at 1.0 mol, and the amount of ethylene carbonate used was 1.8 mol. The rest was the same as in Example 1.

[0091] The yield and purity of the obtained 2-imidazolidine ketone are shown in Table 2 below.

[0092] Table 2

[0093] Urea: Ethylene Carbonate Molar Ratio 2-Imidazolidinone yield (%) HPLC purity (%) Example 1 1:1.25 97.8 99.8 Example 3-1 1:1.0 95.0 99.5 Example 3-2 1:1.5 97.5 99.6 Comparative Example 1-1 1:0.8 90.0 98.5 Comparative Examples 1-2 1:1.8 97.0 99.0

[0094] Example 4-1: Compared with Example 1, the following changes are made:

[0095] The amount of SMO-IL catalyst was adjusted to 1% of the urea mass. That is, the amount of urea remained unchanged at 1.0 mol, and the amount of catalyst was adjusted to 0.6 g. The rest was the same as in Example 1.

[0096] Example 4-2: Compared to Example 1, the following changes are made:

[0097] The amount of SMO-IL catalyst was adjusted to 2% of the urea mass. That is, the amount of urea remained unchanged at 1.0 mol, and the amount of catalyst was adjusted to 1.2 g. The rest was the same as in Example 1.

[0098] Example 4-3: Compared to Example 1, the following changes are made:

[0099] The amount of SMO-IL catalyst was adjusted to 4% of the urea mass. That is, the amount of urea remained unchanged at 1.0 mol, and the amount of catalyst was adjusted to 2.4 g. The rest was the same as in Example 1.

[0100] Example 4-4: Compared to Example 1, the following changes are made:

[0101] The amount of SMO-IL catalyst was adjusted to 5% of the urea mass. That is, the amount of urea remained unchanged at 1.0 mol, and the amount of catalyst was adjusted to 3 g. The rest was the same as in Example 1.

[0102] Comparative Example 2-1: Compared with Example 1, the following changes were made:

[0103] The amount of SMO-IL catalyst was adjusted to 0.5% of the urea mass. That is, the amount of urea remained unchanged at 1.0 mol, and the amount of catalyst was adjusted to 0.3 g. The rest was the same as in Example 1.

[0104] Comparative Example 2-2: Compared with Example 1, the following changes were made:

[0105] The amount of SMO-IL catalyst was adjusted to 6% of the urea mass. That is, the amount of urea remained unchanged at 1.0 mol, and the amount of catalyst was adjusted to 3.6 g. The rest was the same as in Example 1.

[0106] The yield and purity of the obtained 2-imidazolidine ketone are shown in Table 3 below.

[0107] Table 3

[0108]

[0109] Example 5-1: Compared to Example 1, the following changes were made: the reaction temperature was adjusted to 150°C. Everything else remained the same as in Example 1.

[0110] Example 5-2: Compared to Example 1, the following changes were made: the reaction temperature was adjusted to 130°C. Everything else remained the same as in Example 1.

[0111] Example 5-3: Compared to Example 1, the following changes were made: the reaction time was adjusted to 4 hours. Everything else is the same as Example 1.

[0112] Example 5-4: Compared to Example 1, the following changes were made: the reaction time was adjusted to 6 hours. Everything else remained the same as Example 1.

[0113] Comparative Example 3: Compared to Example 1, the following changes were made: the reaction time was adjusted to 3 hours. Everything else was the same as in Example 1.

[0114] The yield and purity of the obtained 2-imidazolidine ketone are shown in Table 4 below.

[0115] Table 4

[0116]

[0117] Comparative Example 4-1: Compared to Example 1, the following changes were made: no catalyst (blank control) was used to evaluate the reaction without a catalyst.

[0118] Comparative Example 4-2: Compared with Example 1, the following changes were made: concentrated sulfuric acid (H2SO4, 98%) was used as the catalyst; the amount of catalyst remained unchanged at 1.8 g, and the rest was the same as in Example 1.

[0119] Comparative Examples 4-3: Compared with Example 1, the following changes were made: p-toluenesulfonic acid (p-TsOH) was used as the catalyst, the amount of catalyst remained unchanged at 1.8 g, and the rest was the same as in Example 1.

[0120] Comparative Example 4-4: Compared with Example 1, the following changes were made: Amberlyst-15 (commercially available acidic ion exchange resin) was used as the catalyst, the amount of catalyst remained unchanged at 1.8 g, and the rest was the same as in Example 1.

[0121] Comparative Examples 4-5: Compared with Example 1, the following changes were made: ZSM-5 zeolite (commercially available solid acid catalyst) was used as the catalyst, the amount of catalyst remained unchanged at 1.8 g, and the rest was the same as in Example 1.

[0122] Comparative Examples 4-6: Compared with Example 1, the following changes were made: 1-Butyl-3-methylimidazolium bromide was used as the catalyst; the amount of catalyst remained unchanged at 1.8 g, and the rest was the same as in Example 1.

[0123] The yield and purity of the obtained 2-imidazolidine ketone are shown in Table 5 below.

[0124] Table 5

[0125]

[0126] Example 6: Catalyst Application Experiment

[0127] The SMO-IL catalyst washed with hot water in Example 1 was vacuum dried at 80°C for 12 hours to obtain the recovered catalyst. Each reuse experiment used the same reaction conditions as in Example 1: 1.0 mol urea, 1.25 mol ethylene carbonate, reaction temperature 140°C, and reaction time 5 hours. New SMO-IL catalyst was added until the total amount reached 1.8 g. The catalyst was reused several times, and the yield and HPLC purity of the 2-imidazolium ketone were recorded for each reaction. The results are shown in Table 6.

[0128] Table 6: Experimental Results of Catalyst Application

[0129] Number of times to apply 2-Imidazolidinone yield (%) HPLC purity (%) First instance (Example 1) 97.8 99.8 2nd time 97.5 99.7 3rd 97.1 99.6 4th 96.6 99.5 5th 96.2 99.4

[0130] Finally, it should be noted that the above examples are merely some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A process for the preparation of a sulfonic acid functionalized ionic liquid catalyst, characterized in that The method comprises the following steps: (1) synthesis of PMO carrier: (2) sulfonic acid functionalization: The sulfonic acid functionalized material SMO-SO3H is prepared by using the PMO carrier; (3) immobilization and activation of ionic liquid: The sulfonic acid functionalized material SMO-SO3H is reacted with 1-aminopropyl-3-methyl imidazole bromide salt to obtain the sulfonic acid functionalized ionic liquid catalyst.

2. The method for preparing the sulfonic acid functionalized ionic liquid catalyst according to claim 1, characterized in that: (1) synthesis of PMO carrier: The template agent P123 is dissolved in hydrochloric acid aqueous solution, tetraethyl orthosilicate and 1,2-bis(triethoxysilyl)ethane are added, and first stirring reaction is carried out at 40±5°C for 24±1 hours, then static crystallization is carried out at 100±10°C for 48±2 hours, and then washing, drying and calcination are carried out to obtain the PMO carrier; The mass ratio of the template agent P123 to tetraethyl orthosilicate is 1:2.05~2.15, and the mass ratio of tetraethyl orthosilicate to 1,2-bis(triethoxysilyl)ethane is 1:1.1~1.2; (2) sulfonic acid functionalization: The PMO carrier is placed in a low-temperature plasma reactor, vacuumized to 10±5 Pa, and then mixed gas of sulfur dioxide and inert gas is introduced, and the pressure is maintained at 50±5 Pa; under the condition of radio frequency, the PMO carrier is subjected to plasma treatment for 20~60 minutes, and the obtained product after plasma treatment is named; in the mixed gas, the volume ratio of sulfur dioxide to argon is 1:2~7; Then, the product after plasma treatment is transferred to a tube furnace, and heat treatment is carried out at 250~350°C for 2±0.2 hours in an oxygen atmosphere; after cooling to room temperature, SMO-SO3H is obtained; (3) immobilization and activation of ionic liquid: SMO-SO3H is stirred and reacted with 1-aminopropyl-3-methyl imidazole bromide salt in a solvent for 3~5 hours; the mass ratio of SMO-SO3H to 1-aminopropyl-3-methyl imidazole bromide salt is 1:1.2~1.3; Then, filtration is carried out, the obtained solid is first subjected to Soxhlet extraction in a solvent, and then is immersed in a sulfuric acid solution with a concentration of (1±0.2) mol / l for ion exchange; after water washing and drying, the sulfonic acid functionalized ionic liquid catalyst is obtained.

3. The method of claim 2, wherein the sulfonic acid functionalized ionic liquid catalyst is prepared by the process comprising: a) reacting a sulfonic acid with a quaternary ammonium salt to form a sulfonic acid functionalized ionic liquid catalyst; and b) recovering the sulfonic acid functionalized ionic liquid catalyst. In step (1): The concentration of the hydrochloric acid aqueous solution is (1.6±0.2) mol / L; the mass ratio of the template agent P123 to the hydrochloric acid aqueous solution is 1g / 35~40mL.

4. The method of claim 3, wherein the sulfonic acid functionalized ionic liquid catalyst is prepared by the reaction of a sulfonic acid with an ionic liquid. In step (1): The washing is carried out by fully washing with deionized water and anhydrous ethanol; The drying is vacuum drying at 80±10°C for 12±1 hours; The calcination is calcination at 550±30°C for 6±0.5 hours.

5. The method of claim 2, 3 or 4, wherein the sulfonic acid functionalized ionic liquid catalyst is prepared by the process comprising the steps of: a) reacting a sulfonic acid with a quaternary ammonium salt to form a sulfonic acid functionalized ionic liquid catalyst; and b) recovering the sulfonic acid functionalized ionic liquid catalyst. In step (2): the radio frequency power is 50~130 W.

6. The method of claim 5, wherein the sulfonic acid functionalized ionic liquid catalyst is prepared by the process comprising: a) reacting a sulfonic acid with a quaternary ammonium salt to form a sulfonic acid functionalized ionic liquid catalyst; and b) recovering the sulfonic acid functionalized ionic liquid catalyst. In step (2): The inert gas is argon.

7. The method for preparing the sulfonic acid functionalized ionic liquid catalyst according to any one of claims 2 to 6, characterized in that... In step (3): The solvent during the reaction is acetonitrile, The Soxhlet extraction is carried out by using acetonitrile, and the Soxhlet extraction time is 22~26h; The ion exchange in the sulfuric acid solution is carried out for 10~14h; The drying is vacuum drying at 80±10°C for 12±1 hours.

8. A method of synthesizing 2-imidazolidinone, characterized by: The sulfonic acid functionalized ionic liquid catalyst prepared by any one of the methods of claims 1-7, The sulfonic acid functionalized ionic liquid catalyst is recovered by hot filtration after the reaction is completed, and the filtrate obtained is subjected to post-treatment to obtain 2-imidazolidinone. The molar ratio of the urea to the ethylene carbonate is 1:0.8-1.

8. The amount of the sulfonic acid functionalized ionic liquid catalyst is 1%-5% of the mass of the urea.

9. The method of synthesizing 2-imidazolidinones according to claim 8, characterized by: The sulfonic acid functionalized ionic liquid catalyst is washed by using hot water at 60±10°C after the reaction is completed and cooled to 60±10°C for hot filtration.

10. The method of synthesizing 2-imidazolidinone according to claim 8 or 9, characterized in that: The post-treatment is that the filtrate / combined liquid is first subjected to reduced-pressure distillation, and the residue after the reduced-pressure distillation is recrystallized with a mixture of ethanol and water to obtain 2-imidazolidinone. The mixture of ethanol and water, ethanol:water=1:(1±0.1) by volume.

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