Reaction control phase transfer catalyst, preparation method thereof and method for catalytically synthesizing 2-pyrazoline

Abstract

The invention provides a reaction control phase transfer catalyst, a preparation method thereof and a method for catalytically synthesizing 2-pyrazoline, belongs to the technical field of aerospace industry, and aims to solve the technical problems that a solid catalyst is difficult to separate and recycle, poor in reutilization and easy to lose. The preparation method of the reaction control phase transfer catalyst comprises the following steps: mixing and dissolving a bidentate nitrogen heterocyclic compound, organic sulfonic acid and a solvent, then carrying out a reaction, after the reaction is finished, carrying out rotary evaporation and washing to separate out crystals, and drying to prepare the reaction control phase transfer catalyst. The reaction control phase transfer catalyst is an unconventional ionic liquid which is in a solid state at normal temperature. The novel reaction control phase transfer catalyst is applied to the catalytic synthesis reaction of 2-pyrazoline for the first time, in the reaction process, the novel reaction control phase transfer catalyst shows a peculiar liquid-solid self-separation phenomenon, reaction and separation coupling strengthening is achieved, and the efficient and green synthesis reaction process is guided out. More importantly, stable precipitation with high recovery rate of the reaction control phase transfer catalyst is realized, the purpose of repeated application of the catalyst is realized, and the problems of greenization, energy conservation, low comprehensive cost and the like in the process of the traditional inorganic / organic acid catalyst, solid catalyst and the like which are widely used in the industry at present can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of aerospace industry, and in particular relates to a reaction-controlled phase transfer catalyst and a preparation method thereof, and a method for catalytically synthesizing 2-pyrazoline. Background Art

[0002] As the power core of the engine, high-energy fuel is an important guarantee for the development of the aerospace field. Tension ring hydrocarbon fuels have the advantages of high density and high volume calorific value. Focusing on the major strategic needs of my country's new generation of manned launch vehicles and high-range unmanned aerial vehicles to improve their capabilities, the development of tension ring hydrocarbon fuels can not only improve the propulsion speed requirements of advanced aircraft, but also increase the endurance requirements of existing aircraft. At present, it is urgent to break through technical difficulties such as catalyst conversion rate and selectivity, process optimization and amplification, efficient purification and quality control, and form a green and efficient core technology for the preparation of high-energy fuels. At present, cyclopropane liquid hydrocarbon fuels are mainly obtained by high-temperature denitrogenation of 2-pyrazoline. The reaction equation is as follows:

[0003]

[0004] At present, the traditional synthesis method of 2-pyrazoline is mainly a homogeneous acid catalyzed ketazine isomerization cyclization method, but this method will produce a large amount of acid-containing wastewater. In recent years, new catalysts such as solid acids and ionic liquids have been reported one after another. For example, patent publication number CN117753474A discloses a sulfonic acid solid acid catalyst and a preparation method thereof, and a method for catalyzing ketazine isomerization into 2-pyrazoline, wherein the solid acid catalyst is mainly composed of methylsulfonic acid and amorphous silicon dioxide as a carrier, and the main feature of the solid acid catalyst is a high B acid center. For example, patent publication number CN118084789A discloses a method for synthesizing pyrazoline by a zirconium salt catalyzed ketazine internal cyclization reaction, using zirconium salt as a catalyst. However, they still have the disadvantages of separation and recovery difficulty, poor reuse, and easy loss. Summary of the invention

[0005] In view of the technical problems of the difficulty in separation and recovery of solid catalysts, poor reuse and easy loss, the present invention proposes a reaction-controlled phase-transfer catalyst and a preparation method thereof and a method for catalytic synthesis of 2-pyrazoline, wherein the reaction-controlled phase-transfer catalyst is a class of unconventional ionic liquids that are solid at room temperature. And it is applied to the catalytic synthesis of 2-pyrazoline for the first time. In this reaction process, the novel reaction-controlled phase-transfer catalyst shows a peculiar liquid-solid self-separation phenomenon, realizes the coupling enhancement of reaction and separation, and leads to an efficient and green synthesis reaction process. More importantly, the stable precipitation of the high recovery rate of the reaction-controlled phase-transfer catalyst is realized, the invention purpose of the repeated use of the catalyst is realized, and the problems of greening, energy saving, and low comprehensive cost of the processes of the conventional inorganic / organic acid catalysts and solid catalysts widely used in the industry can be overcome.

[0006] In order to achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] A method for preparing a reaction-controlled phase transfer catalyst comprises the following steps: mixing and dissolving a bidentate nitrogen heterocyclic compound, an organic sulfonic acid and a solvent, then reacting, and after the reaction is completed, rotary evaporation, washing to precipitate crystals and drying to obtain a reaction-controlled phase transfer catalyst.

[0008] The bidentate nitrogen heterocyclic compound in step (1) is 1,10-phenanthroline, 2,2'-bipyridine, or 4,4'-bipyridine.

[0009] The organic sulfonic acid is any one of trifluoromethanesulfonic acid, methanesulfonic acid and chlorosulfonic acid.

[0010] The solvent is an alcohol solvent; the alcohol solvent is any one of methanol, ethanol, isopropanol and n-propanol; the ratio of the alcohol solvent to the bidentate nitrogen heterocyclic compound is (0.1-1) L: 1 moL.

[0011] The molar ratio of the bidentate nitrogen heterocyclic compound to the organic sulfonic acid is 1:(2-1).

[0012] The reaction temperature is 25-80°C and the reaction time is 6-24h.

[0013] Preferably, the structural formula of the reaction-controlled phase transfer catalyst is as shown in any one of Formulas I-III:

[0014]

[0015] A method for synthesizing 2-pyrazoline by using a reaction-controlled phase transfer catalyst comprises the following steps: mixing a ketazine and a reaction-controlled phase transfer catalyst, heating the mixture to a temperature above the melting point of the reaction-controlled phase transfer catalyst to react, and preparing a 2-pyrazoline compound.

[0016] The reaction-controlled phase transfer catalyst is a non-conventional ionic liquid that is solid at room temperature and has dual acid centers of B acid and L acid. When the reaction is completed, the liquid and the solid are separated by themselves.

[0017] The structural formula of the ketazine is shown in Formula IV:

[0018]

[0019] The structural formula of the 2-pyrazoline compound is shown in Formula V:

[0020]

[0021] The reaction temperature is 90-105°C and the reaction time is 2-8h.

[0022] The molar ratio of the ketazine to the reaction-controlled phase transfer catalyst is (10:1)-(60:1).

[0023] The beneficial effects of the present invention are as follows: the reaction-controlled phase transfer catalyst is formed by a bidentate nitrogen heterocyclic compound and an organic sulfonic acid through a proton transfer reaction, and has both B acid and L acid dual acid centers, and is a non-conventional ionic liquid in a solid state at room temperature. The dual active centers of the reaction-controlled phase transfer catalyst are utilized to achieve efficient catalytic pyrazoline synthesis, with a ketone nitrogen conversion rate of up to 90%, and a 2-pyrazoline selectivity of up to 99%. At the same time, the reaction-controlled phase transfer catalyst exhibits a peculiar liquid-solid self-separation phenomenon in the catalytic synthesis of 2-pyrazoline due to its special properties, achieves enhanced coupling of reaction and separation, and leads to an efficient and green synthetic reaction process. More importantly, the stable precipitation of the high recovery rate of the reaction-controlled phase transfer catalyst is achieved, the invention purpose of the catalyst is achieved, and the problems of greening, energy saving, and low comprehensive cost in the processes of the conventional inorganic / organic acid catalysts and solid catalysts widely used in the industry can be overcome. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 This is a physical picture of the reaction-controlled phase transfer catalyst 1.

[0026] Figure 2 This is a physical picture of the reaction-controlled phase transfer catalyst 2.

[0027] Figure 3This is a physical picture of the reaction-controlled phase transfer catalyst 3.

[0028] Figure 4 This is the state change of the reaction-controlled phase transfer catalyst 1 at the beginning, during and after the reaction of Application Example 4.

[0029] Figure 5 This is a single crystal analysis diagram of the reaction-controlled phase transfer catalyst 1.

[0030] Figure 6 Py-IR spectrum of the reaction-controlling phase transfer catalyst 1.

[0031] Figure 7 Py-IR spectrum of the reaction-controlling phase transfer catalyst 2.

[0032] Figure 8 Py-IR spectrum of the reaction-controlled phase transfer catalyst 3. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] A reaction controlled phase transfer catalyst, the structural formula is The catalyst 1 is recorded as catalyst 1; the preparation method of catalyst 1 comprises the following steps:

[0036] 0.1 mol of 1,10-phenanthroline was weighed and dissolved in 100 ml of ethanol solution to form a uniform solution, and then 0.2 mol of organic sulfonic acid was slowly added to the ethanol solution, and stirred vigorously at room temperature for 30 min; the temperature was gradually raised to 60°C and maintained for 8 h; the ethanol was completely removed by rotary evaporation, and the unreacted raw materials were removed by repeated washing with toluene until crystals precipitated; vacuum drying was maintained at 80°C for 12 h to obtain a reaction-controlled phase transfer catalyst 1 (such as Figure 1 Catalyst 1: 1 H NMR (500MHz, DMSO-d6) δ9.23 (dd, J=4.9, 1.5Hz, 1H), 9.00 (dd, J=8.2, 1.5Hz, 1H), 8.24 (s, 1H), 8.18 (dd, J=8.2, 4.9Hz, 1H), 2.50 (s, 3H); MS (ESI): m / z 181.08[C 12 H8N2–H]+ .Anal.Calcd.for C 14 H 16 N2O6S2: C, 45.15; H, 4.33; N, 7.52. Found: C, 42.71; H, 4.71; N, 7.07.

[0037] Example 2

[0038] A reaction controlled phase transfer catalyst, the structural formula is The catalyst 2 is recorded as catalyst 2; the preparation method of catalyst 2 comprises the following steps:

[0039] 0.1 mol of 1,10-phenanthroline was weighed and dissolved in 150 ml of ethanol solution to form a uniform solution, and then 0.1 mol of organic sulfonic acid was slowly added to the ethanol solution, and stirred vigorously at room temperature for 30 min; the temperature was gradually raised to 60°C and maintained for 8 h; the ethanol was completely removed by rotary evaporation, and the unreacted raw materials were removed by repeated washing with toluene until crystals precipitated; vacuum drying was maintained at 80°C for 12 h to obtain a reaction-controlled phase transfer catalyst 2 (such as Figure 2 Catalyst 2: 1 H NMR (500MHz, DMSO-d6) δ9.25 (dd, J=4.9, 1.6Hz, 1H), 9.01 (dd, J=8.2, 1.6Hz, 1H), 8.27 (s, 1H), 8.19 (dd, J=8.2, 4.9Hz, 1H), 2.41 (s, 1H); MS (ESI): m / z 181.08[C 12 H8N2–H] + .Anal.Calcd.for C 13 H 12 N2O3S:C,56.51;H,4.38;N,10.14.Found:C,56.14;H,4.33;N,10.19.

[0040] Example 3

[0041] A reaction controlled phase transfer catalyst, the structural formula is The preparation method of catalyst 3 comprises the following steps:

[0042] 0.1 mol of 2,2'-bipyridine was weighed and dissolved in 50 ml of ethanol solution to form a uniform solution, and then 0.2 mol of organic sulfonic acid was slowly added to the ethanol solution, and stirred vigorously at room temperature for 30 min; the temperature was gradually raised to 60°C and maintained for 8 h; the ethanol was completely removed by rotary evaporation, and the unreacted raw materials were removed by repeated washing with toluene until crystals precipitated; vacuum drying was maintained at 80°C for 12 h to obtain the reaction-controlled phase transfer catalyst 3 ((such as Figure 3 Catalyst 3: 1H NMR (300MHz, DMSO-d6) d (ppm): 11.27 (OH, s), 8.89 (1H, d), 8.87 (1H, d), 8.66 (1H, d), 8.63 (1H, d), 8.40 (2H, t), 7.87 (1H, t), 7.86 (1H, t). 13C NMR (75MHz, DMSO-d6) d (ppm): 147.86, 147.04, 143.38, 127.65, 124.22. MS (ESI): m / z 157.08 Anal.Calcd.forC10H12N2O8S2:C,34.09;H,3.41;N,7.95.Found:C,34.10;H,3.43;N,7.92.

[0043] Example 4

[0044] A reaction-controlled phase transfer catalyst, the preparation method of which comprises the following steps:

[0045] Weigh 0.1 mol of 4,4'-bipyridine and dissolve it in 10 ml of isopropanol solution to form a uniform solution, then slowly add 0.15 mol of trifluoromethanesulfonic acid into the isopropanol solution, vigorously stir at 25°C for 30 minutes, and keep it for 24 hours; completely remove ethanol by rotary evaporation, and repeatedly wash with toluene to remove unreacted raw materials until crystals precipitate; vacuum dry and keep it at 80°C for 12 hours to obtain a reaction-controlled phase transfer catalyst.

[0046] Example 5

[0047] A reaction-controlled phase transfer catalyst, the preparation method of which comprises the following steps:

[0048] Weigh 0.1 mol of 1,10-phenanthroline and dissolve it in 100 ml of ethanol solution to form a uniform solution. Then slowly add 0.15 mol of methanesulfonic acid into the ethanol solution, stir vigorously at 25°C for 30 minutes, gradually raise the temperature to 80°C and maintain for 6 hours; completely remove the ethanol by rotary evaporation, and repeatedly wash with toluene to remove the unreacted raw materials until crystals precipitate; vacuum dry and maintain at 80°C for 12 hours to obtain a reaction-controlled phase transfer catalyst.

[0049] The reaction-controlled phase transfer catalyst used in the following application examples is catalyst 1-3 prepared in Example 1-3.

[0050] Application Example 1

[0051] A reaction-controlled phase transfer catalyst 1 catalyzes the isomeric cyclization of acetone ketoazoline to obtain 3,5,5-trimethyl-2-pyrazoline, wherein the steps are:

[0052] 1) Add acetone ketazine (0.4 mol, 44.8 g) into a 250 mL three-necked flask and continuously introduce nitrogen to keep the system in an inert environment;

[0053] 2) Then, catalyst 1 (0.01 mol, 3.72 g) was added;

[0054] 3) Stir at 200 rpm, start heating, slowly raise the temperature to 100°C, and react for 8 hours;

[0055] 4) Cool down to room temperature and use Agilent GC-8890 for quantitative analysis using internal standard method.

[0056] Application Example 2

[0057] A reaction-controlled phase transfer catalyst 1 catalyzes the isomeric cyclization of butanone ketone to obtain 3,5-diethyl-5-methyl-2-pyrazoline, wherein the steps are:

[0058] 1) Add butanone ketazine (0.4 mol, 56 g) into a 250 mL three-necked flask and continuously introduce nitrogen to keep the system in an inert environment;

[0059] 2) Then, catalyst 1 (0.01 mol, 3.72 g) was added;

[0060] 3) Stir at 300 rpm, start heating, slowly raise the temperature to 100°C, and react for 8 hours;

[0061] 4) Cool down to room temperature and use Agilent GC-8890 for quantitative analysis using internal standard method.

[0062] Application Example 3

[0063] A reaction-controlled phase transfer catalyst 1 catalyzes the isomeric cyclization of 2-pentanone ketoazoline to obtain 3,5-dipropyl-5-methyl-2-pyrazoline, wherein the steps are:

[0064] 1) Add 2-pentanone ketazine (0.4 mol, 67.2 g) into a 250 mL three-necked flask and continuously introduce nitrogen to keep the system in an inert environment;

[0065] 2) Then, catalyst 1 (0.01 mol, 3.72 g) was added;

[0066] 3) Stir at 300 rpm, start heating, slowly raise the temperature to 100°C, and react for 8 hours;

[0067] 4) Cool down to room temperature and use Agilent GC-8890 for quantitative analysis using internal standard method.

[0068] Application Example 4

[0069] A reaction-controlled phase transfer catalyst 1 catalyzes the isomeric cyclization of 2-octanone ketone to obtain 3,5-dihexyl-5-methyl-4,5-dihydro-1H-pyrazole, and the specific steps are:

[0070] 1) Add 2-octanone ketazine (0.2 mol, 50.4 g) into a 250 mL three-necked flask and continuously introduce nitrogen to keep the system in an inert environment;

[0071] 2) Then, catalyst 1 (0.005 mol, 1.86 g) was added;

[0072] 3) Stir at 300 rpm, start heating, slowly raise the temperature to 100°C, and react for 8 hours;

[0073] 4) Cool down to room temperature and use Agilent GC-8890 for quantitative analysis using internal standard method.

[0074] Figure 4 The figure shows the state changes of the reaction-controlled phase transfer catalyst 1 at the beginning, during and after the reaction. It can be seen from the figure that the reaction-controlled phase transfer catalyst 1 is solid in 2-octanone ketazine at first. As the temperature rises, the reaction-controlled phase transfer catalyst 1 dissolves and participates in the catalytic reaction. After the reaction is completed, the reaction liquid returns to room temperature and the reaction-controlled phase transfer catalyst 1 re-precipitates.

[0075] Application Example 5

[0076] A reaction-controlled phase transfer catalyst 1 catalyzes the isomeric cyclization of cyclopropyl ketone to obtain 5-methyl-3,5-dicyclopropylpyrazoline, wherein the steps are:

[0077] 1) Cyclopropyl ketazine (0.3 mol, 49.2 g) was added into a 250 mL three-necked flask and nitrogen was continuously introduced to keep the system in an inert environment;

[0078] 2) Then, catalyst 1 (0.0075 mol, 2.79 g) was added;

[0079] 3) Stir at 250 rpm, turn on heating, slowly raise the temperature to 100°C, and react for 8 hours;

[0080] 4) Cool down to room temperature and use Agilent GC-8890 for quantitative analysis using internal standard method.

[0081] Application Example 6

[0082] A reaction-controlled phase transfer catalyst 1 catalyzes the isomeric cyclization of 2-octanone ketone to obtain 3,5-dihexyl-5-methyl-4,5-dihydro-1H-pyrazole, and the steps are:

[0083] 1) Add 2-octanone ketazine (0.2 mol, 50.4 g) into a 250 mL three-necked flask and continuously introduce nitrogen to keep the system in an inert environment;

[0084] 2) Then, catalyst 1 (0.02 mol, 7.44 g) was added;

[0085] 3) Start stirring at 300 rpm, start heating, slowly raise the temperature to 90°C, and react for 8 hours;

[0086] 4) Cool down to room temperature and use Agilent GC-8890 for quantitative analysis using internal standard method.

[0087] Application Example 7

[0088] A reaction-controlled phase transfer catalyst 1 catalyzes the isomeric cyclization of 2-octanone ketone to obtain 3,5-dihexyl-5-methyl-4,5-dihydro-1H-pyrazole, and the steps are:

[0089] 1) Add 2-octanone ketazine (0.2 mol, 50.4 g) into a 250 mL three-necked flask and continuously introduce nitrogen to keep the system in an inert environment;

[0090] 2) Then, catalyst 1 (0.0025 mol, 0.93 g) was added;

[0091] 3) Start stirring at 300 rpm, start heating, slowly raise the temperature to 105°C, and react for 8 hours;

[0092] 4) Cool down to room temperature and use Agilent GC-8890 for quantitative analysis using internal standard method.

[0093] Application Example 8

[0094] A reaction-controlled phase transfer catalyst 2 catalyzes the isomeric cyclization of 2-octanone ketone to obtain 3,5-dihexyl-5-methyl-4,5-dihydro-1H-pyrazole, and the steps are:

[0095] 1) Add 2-octanone ketazine (0.2 mol, 50.4 g) into a 250 mL three-necked flask and continuously introduce nitrogen to keep the system in an inert environment;

[0096] 2) Then, catalyst 2 (0.005 mol, 1.38 g) was added;

[0097] 3) Stir at 300 rpm, start heating, slowly raise the temperature to 100°C, and react for 8 hours;

[0098] 4) Cool down to room temperature and use Agilent GC-8890 for quantitative analysis using internal standard method.

[0099] Application Example 9

[0100] A reaction-controlled phase transfer catalyst 3 catalyzes the isomeric cyclization of cyclopropyl ketone to obtain 5-methyl-3,5-dicyclopropylpyrazoline, wherein the steps are:

[0101] 1) Cyclopropyl ketazine (0.3 mol, 49.2 g) was added into a 250 mL three-necked flask and nitrogen was continuously introduced to keep the system in an inert environment;

[0102] 2) Then, catalyst 3 (0.0075 mol, 1.89 g) was added;

[0103] 3) Stir at 250 rpm, turn on heating, slowly raise the temperature to 100°C, and react for 8 hours;

[0104] 4) Cool down to room temperature and use Agilent GC-8890 for quantitative analysis using internal standard method.

[0105] Reaction Control Phase Transfer Catalyst 1-9 Recovery

[0106] The recovery of reaction-controlled phase transfer catalyst 1-9 is as follows: after the reaction of application example 1-9 is completed, the reaction liquid is cooled to room temperature, the catalyst and the reaction liquid are separated by liquid-solid self-separation, the oil layer is filtered out, and the catalyst can be used directly without further treatment.

[0107] Table 1 Experimental data of application examples 1-9

[0108]

[0109]

[0110] The reaction-controlled phase transfer catalyst 1-3 was subjected to a cyclic reaction. The reaction-controlled phase transfer catalyst 1-3 recovered from application examples 4, 8 and 9 was subjected to the same conditions as the corresponding application examples (including reaction temperature, molar ratio, stirring speed, reaction time, etc.). The catalytic experiment was repeated 5 times. The results are shown in Table 2.

[0111] Table 2 Repeated application examples 4, 8 and 9 experimental conditions (reaction controlled phase transfer catalyst 1-3)

[0112]

[0113] The catalytic efficiency and universality of the catalysts in Application Examples 1-9 are tested, as shown in Table 1. The results show that the new reaction-controlled phase transfer catalysts 1-3 prepared by the present invention have good catalytic effects and provide a new catalyst design idea for pyrazoline synthesis. Table 2 is the evaluation of the reusability of the catalysts in Application Examples 4, 8, and 9. The results show that the new reaction-controlled phase transfer catalysts 1-3 still have high catalytic activity after being used three times.

[0114] Further comparison shows that the novel reaction-controlled phase transfer catalyst 1 has a more excellent catalytic effect, and further characterization and analysis are performed on it. The crystal structure parameters of catalyst 1 are obtained by using an X-ray single crystal diffractometer. Figure 5 The results show that the crystal structure parameters of catalyst 1 are orthorhombic, Pna21 space group, unit cell parameters a=90°, β=90°, γ=90°, Dc=1.513Mg / m 3 , Z = 4. At the same time, analysis of the molecular structure ball-and-stick diagram and crystal structure shows that the catalyst 1 molecule is not entirely composed of positively charged [C 12 H8N2–H] + and negatively charged [CH3SO3] - The ionic compound is different from the traditional ionic liquid. It contains an NH covalent bond similar to that of ionic liquids and an N…H hydrogen bond. That is to say, the first CH3SO3H will form a stable NH covalent bond with one of the N sites of the cation. The second CH3SO3H can only connect with the second N phase in the form of a hydrogen bond due to the weakened alkalinity of the second N site and the inevitable steric effect. The hydrogen bond can restrain CH3SO3H from easily falling off the cation, but it can ensure that the generated complex releases more H + , which is why the catalytic activity of catalyst 1 is much higher than that of catalyst 2. At the same time, since the higher the symmetry of catalyst 3, the lower the corresponding acidity, this is also one of the reasons why the catalytic activity of catalyst 3 is lower than that of catalyst 1.

[0115] In addition, through pyridine infrared testing, it can be seen that catalysts 1-3 all have dual catalytic active centers (L acid site and B acid site), such as Figure 6-8 .

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a reaction-controlled phase transfer catalyst, characterized in that: The following steps are involved: The bidentate nitrogen heterocyclic compound, organic sulfonic acid and solvent are mixed and dissolved, and then reacted. After the reaction is completed, rotary evaporation, washing, crystal precipitation and drying are performed to obtain a reaction-controlled phase transfer catalyst.

2. The method for preparing a reaction-controlled phase transfer catalyst according to claim 1, characterized in that: The bidentate nitrogen heterocyclic compound in step (1) is 1,10-phenanthroline, 2,2'-bipyridine, or 4,4'-bipyridine.

3. The method for preparing a reaction-controlled phase transfer catalyst according to claim 2, characterized in that: The organic sulfonic acid is any one of trifluoromethanesulfonic acid, methanesulfonic acid and chlorosulfonic acid.

4. The method for preparing a reaction-controlled phase transfer catalyst according to any one of claims 1 to 3, characterized in that: The solvent is an alcohol solvent; the alcohol solvent is any one of methanol, ethanol, isopropanol and n-propanol; the ratio of the alcohol solvent to the bidentate nitrogen heterocyclic compound is (0.1-1) L: 1 moL.

5. The method for preparing a reaction-controlled phase transfer catalyst according to claim 4, characterized in that: The molar ratio of the bidentate nitrogen heterocyclic compound to the organic sulfonic acid is 1:(2-1).

6. The method for preparing a reaction-controlled phase transfer catalyst according to claim 5, characterized in that: The reaction temperature is 25-80°C and the reaction time is 6-24h.

7. A reaction-controlled phase-transfer catalyst prepared by the method according to any one of claims 1 to 6.

8. The method for synthesizing 2-pyrazoline by catalysis of a reaction-controlled phase-transfer catalyst according to claim 7, comprising the following steps: mixing a ketazine and a reaction-controlled phase-transfer catalyst, heating the mixture to a temperature above the melting point of the reaction-controlled phase-transfer catalyst to react and preparing a 2-pyrazoline compound.

9. The method for synthesizing 2-pyrazoline using a reaction-controlled phase-transfer catalyst according to claim 8, characterized in that: The reaction temperature is 90-105°C and the reaction time is 2-8h.

10. The method for synthesizing 2-pyrazoline using a reaction-controlled phase transfer catalyst according to claim 9, characterized in that: The molar ratio of the ketazine to the reaction-controlled phase transfer catalyst is (10:1)-(60:1).

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