Sulfur-doped activated carbon supported palladium metal catalyst, its preparation method and application

Abstract

The application discloses a sulfur-doped activated carbon supported palladium metal catalyst and a preparation method and application thereof. The preparation method comprises the following steps: obtaining a sulfur-doped activated carbon carrier; loading a palladium metal precursor compound on the sulfur-doped activated carbon carrier through an impregnation method; and reducing by using a liquid phase reducing agent to obtain the sulfur-doped activated carbon supported palladium metal catalyst. The application provides application of the sulfur-doped activated carbon supported palladium metal catalyst in synthesis of 1,3-dimethyl-2-imidazolidinone by a hydrogenation method, which exhibits excellent activity and high selectivity under relatively mild conditions, shortens a reaction time, and has good catalytic stability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of catalyst preparation, and particularly relates to a sulfur-doped activated carbon supported palladium metal catalyst for synthesizing 1,3-dimethyl-2-imidazolinone by a hydrogenation method, and a preparation method and application thereof. BACKGROUND

[0002] 1,3-dimethyl-2-imidazolinone (DMI) is a colorless and transparent strong polar aprotic solvent, which has excellent solvent performance, excellent solubility for inorganic matter, organic matter and part of resin, can be mutually soluble with water in any proportion, and has the advantages of low toxicity, acid and alkali resistance, good stability, high boiling point and flash point, large dielectric constant and the like, so it is widely used in electrochemistry, microelectronics, drug synthesis, petroleum chemical industry and the like. Meanwhile, its performance is better than that of ordinary inert solvents such as dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF) and N-methyl pyrrolidone (NMP), and can replace carcinogenic hexamethylphosphoric triamide (HMPA). In industrial production, it can effectively improve safety, reduce environmental pollution and improve product quality, and is known as a “kingpin solvent”.

[0003] At present, the synthesis method of DMI can be divided into two processes:

[0004] (1) Direct cyclization method: DMI is synthesized by using N,N'-dimethyl ethylenediamine and a carbonylation reagent (phosgene, urea, carbon dioxide, trichloroacetyl chloride, etc.). However, the obvious shortcomings are, for example, harsh reaction conditions, high cost and high toxicity.

[0005] (2) Indirect methylation method: DMI is synthesized by N-methylation reaction of 2-imidazolidinone and an alkylating agent (halomethane, dimethyl sulfate, formaldehyde, etc.). Among them, the industrial process mainly adopts the reductive N-methylation reaction process of 2-imidazolidinone and formaldehyde, which is specifically divided into formic acid method and hydrogenation method. Although the formic acid method is simple and low in cost, the presence of acid causes equipment corrosion and environmental pollution. Compared with the formic acid method, the hydrogenation method is a clean method, which meets the current green and environmentally friendly production process, but still has the disadvantages of low efficiency, high cost and harsh reaction conditions. Overall, the hydrogenation method has room for further optimization and improvement, and gradually develops in a sustainable direction.

[0006] Therefore, it is very meaningful to explore a catalyst with high activity, high selectivity and high stability for synthesizing 1,3-dimethyl-2-imidazolinone by a hydrogenation method. SUMMARY

[0007] To solve the above problems, the application provides a sulfur-doped activated carbon supported palladium metal catalyst for synthesizing 1,3-dimethyl-2-imidazolinone by hydrogenation, a preparation method of the catalyst and application of the catalyst in synthesizing 1,3-dimethyl-2-imidazolinone by hydrogenation.

[0008] To achieve the above-mentioned application purposes, the technical solutions adopted by the application are described as follows.

[0009] In the first aspect, the application provides a preparation method of a sulfur-doped activated carbon supported palladium metal catalyst for synthesizing 1,3-dimethyl-2-imidazolinone by hydrogenation, which comprises the following steps:

[0010] (1) Dissolve a sulfur atom precursor in deionized water, add completely dried activated carbon, fully stir for 6-12 hours, then heat to 60-80 DEG C to evaporate water, and obtain a solid mixture A; the sulfur atom precursor is at least one selected from Na2SO4, Na2S, NaHSO3, Na2SO3, Na2S2O3, K2SO4, K2S, KHSO3, K2SO3, K2S2O3, H2SO4, methyl sulfonic acid, benzene sulfonic acid, p-toluene sulfonic acid, alpha-naphthalene sulfonic acid, beta-naphthalene sulfonic acid, 2-mercaptoethanol, dimethyl sulfone, phenyl vinyl sulfone, and sodium dodecyl sulfate; the sulfur atom precursor and the activated carbon are added according to the theoretical doping amount of sulfur atom y% = m S / (m S +m 活性炭 ) × 100% = 2-10%, wherein m S is the mass of S element contained in the added sulfur atom precursor;

[0011] (2) Dry the solid mixture A in a vacuum oven, then place it in a tube furnace, calcine at 500-800 DEG C under inert atmosphere for 3-5 hours, cool to room temperature, and obtain a sulfur-doped activated carbon carrier, which is denoted as CS y ;

[0012] (3) Add the sulfur-doped activated carbon carrier into a proper amount of deionized water, stir and disperse uniformly at room temperature (preferably stir and disperse for 1-3 hours) to obtain a suspension B; add a palladium metal precursor compound into a proper amount of deionized water, heat to 60-80 DEG C, and keep stirring for 1-3 hours to obtain a solution C; then heat the suspension B to 60-80 DEG C, add the solution C drop by drop into the suspension B, and immerse for 3-5 hours; the suspension B and the solution C are added according to the theoretical loading amount of Pd x% = m Pd / (m Pd +m 硫掺杂活性炭载体 ) × 100% = 3-10%, wherein m Pd is the mass of Pd element contained in the solution C, and m 硫掺杂活性炭载体is the mass of the sulfur-doped activated carbon carrier contained in the suspension B;

[0013] (4) After sufficient impregnation in step (3), add an appropriate amount of alkali liquor to the suspension B to adjust the pH value of the suspension B to 8-11, and then stand for 1.5-2 h; then heat to 60-80℃, slowly add an appropriate amount of aqueous solution containing liquid-phase reducing agent to the suspension B for sufficient reduction; cool the suspension B, filter and wash the filter cake with deionized water repeatedly until the pH of the filtrate is neutral; dry the filter cake to obtain a sulfur-doped activated carbon supported palladium metal catalyst, which is denoted as x%Pd / CS y .

[0014] As a preference, in step (1), the sulfur atom precursor is at least one of Na2SO4, Na2S, NaHSO3, and most preferably Na2SO4.

[0015] As a preference, in step (2), y is 2-7, and most preferably 5.

[0016] As a preference, in step (2), the drying condition is 100-130℃ for 6-12 h.

[0017] As a preference, in step (2), the inert atmosphere is at least one of nitrogen, argon, and helium.

[0018] As a preference, in step (2), the heating rate to the calcination temperature is 1-5℃·min -1 , the calcination temperature is 500-800℃, and the calcination time is 3-5 h; more preferably, the heating rate is 3℃·min -1 , the calcination temperature is 600℃, and the calcination time is 3 h.

[0019] As a preference, in step (3), the palladium metal precursor compound is at least one of tetrachloropalladic acid (H2PdCl4), sodium tetrachloropalladic acid (Na2PdCl4), potassium tetrachloropalladic acid (K2PdCl4), palladium nitrate (Pd(NO3)2), and dichlorotetraammonium palladium (Pd(NH3)4Cl2).

[0020] As a preference, in step (3), when preparing solution C, in addition to the palladium metal precursor compound and deionized water, a dispersant is also added, the dispersant is at least one of polyvinylpyrrolidone and polyethylene glycol, and the mass amount of the dispersant is 5-10% of the mass amount of the sulfur-doped activated carbon carrier.

[0021] As a preference, in step (3), x is 5-10, and most preferably 7.5.

[0022] As preferred, in step (4), the alkaline solution is at least one of ammonia, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution.

[0023] As preferred, in step (4), the liquid phase reducing agent is at least one of sodium borohydride, hydrazine hydrate, and the molar ratio of the liquid phase reducing agent to palladium element is 5-15:1, most preferably 10:1; the reduction time is 1-2h.

[0024] As preferred, in step (4), the drying is to place the filter cake in a vacuum oven and dry at 100-130℃ for 6-12h.

[0025] In the second aspect, the present application provides a sulfur-doped activated carbon supported palladium metal catalyst for synthesizing 1,3-dimethyl-2-imidazolidinone by hydrogenation method, which is prepared by the preparation method according to the first aspect.

[0026] In the third aspect, the present application provides an application of the sulfur-doped activated carbon supported palladium metal catalyst in synthesizing 1,3-dimethyl-2-imidazolidinone by hydrogenation method.

[0027] The application includes the following specific steps: sequentially adding 2-imidazolidinone, deionized water, the sulfur-doped activated carbon supported palladium metal catalyst, and formaldehyde solution into a reaction kettle, and performing continuous hydrogenation reaction under the conditions of 130-160℃, hydrogen pressure of 1-5MPa, and mechanical stirring to synthesize 1,3-dimethyl-2-imidazolidinone. The obtained reaction liquid is subjected to suction filtration, the filter cake is the sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate is subjected to distillation treatment to remove water, and then subjected to quantitative analysis of the target product by using a gas chromatograph.

[0028] As preferred, the mass feeding ratio of the 2-imidazolidinone, deionized water, sulfur-doped activated carbon supported palladium metal catalyst, and formaldehyde solution (37wt.%) is 6:50:0.3:14.

[0029] As preferred, the reaction conditions are as follows: the reaction temperature is 140-160℃, and the hydrogen pressure is 1-2MPa; more preferably, the reaction temperature is 140℃, and the hydrogen pressure is 1MPa.

[0030] As preferred, the mechanical stirring rate is controlled at 700-1000r·min -1 .

[0031] Compared with the prior art, the present application has the following beneficial effects:

[0032] (1) The sulfur-doped activated carbon carrier prepared by the easy-to-implement method of the application enables effective introduction of sulfur species into the activated carbon and stable existence. The defect sites and active sites formed on the carbon surface are conducive to the loading of metal nanoparticles and the activation of reactants. In addition, the carrier has excellent properties such as high specific area and rich pore structure, providing a larger platform for the reaction.

[0033] (2) The sulfur-doped activated carbon-supported palladium metal catalyst of the application, due to the strong interaction between palladium and sulfur atoms, enables palladium nanoparticles to be dispersed and anchored to the defect sites of the carrier, and a synergistic effect is generated with the active sites on the surface of the carrier, promoting the progress of the reaction. At the same time, the addition of the dispersant improves the dispersibility of the palladium nanoparticles.

[0034] (3) Compared with traditional catalysts, the catalyst of the application can make up for the deficiencies such as low activity and complex preparation process. When the catalyst of the application is applied to the reaction of synthesizing 1,3-dimethyl-2-imidazolidinone by the hydrogenation method, it exhibits excellent activity and high selectivity under relatively mild conditions, shortens the reaction time, has good catalytic stability, avoids the use of organic solvents and acids, and practices the concept of green chemistry. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a transmission electron microscope image of the catalyst 7.5% Pd / CS5 prepared in Example 1 of the application;

[0036] Figure 2 is an X-ray diffraction pattern of the catalyst 7.5% Pd / CS5 prepared in Example 1 of the application. DETAILED DESCRIPTION

[0037] The technical solutions of the application will be described in more detail below in conjunction with examples, and the protection scope of the application is not limited to the following detailed description.

[0038] Example 1

[0039] 1. Preparation of a sulfur-doped activated carbon-supported palladium metal catalyst:

[0040] (1) Dissolve 1.1659 g of Na2SO4 in 75 mL of deionized water, add 5 g of completely dried activated carbon (Macklin, 200 mesh, powder), stir thoroughly for 12 h, and then heat to 70℃ to evaporate the water, obtaining a solid mixture A;

[0041] (2) Place the solid mixture A in a vacuum oven and dry at 110℃ for 12 h; then place it in a tube furnace and calcine at 3℃·min -1 to 600℃ under a nitrogen atmosphere, and keep for 3 h, and then cool to room temperature, obtaining a sulfur-doped activated carbon carrier CS5;

[0042] (3) Add 2g of sulfur-doped activated carbon carrier to 30mL of deionized water and stir to disperse at room temperature for 1h to obtain suspension B; separately add 8.1mL of tetrachloropalladium acid aqueous solution (Pd 0.02g·mL⁻¹) -1 Add 20 mL of deionized water, add 0.2 g of polyvinylpyrrolidone (K16-18), heat to 70 °C and stir for 1 h to obtain solution C; then heat suspension B to 70 °C, add solution C dropwise to suspension B, and stir and soak for 5 h.

[0043] (4) After thorough soaking in step (3), add 0.1 g·mL -1 Sodium hydroxide aqueous solution was added to suspension B, the pH of suspension B was adjusted to 9, and then it was allowed to stand for 1.5 h; then the temperature was raised to 70 °C, and 10 mL of aqueous solution containing 0.58 g sodium borohydride was slowly added dropwise to suspension B, and reduction was carried out for 1 h; suspension B was cooled and filtered, and the filter cake was repeatedly washed with deionized water until the pH of the filtrate was neutral; the filter cake was placed in a vacuum oven and dried at 110 °C for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 7.5% Pd / CS5.

[0044] 2. Application of catalysts in the hydrogenation synthesis of 1,3-dimethyl-2-imidazolinone:

[0045] Add 12g of 2-imidazolium ketone, 100mL of deionized water, 0.6g of sulfur-doped activated carbon-supported palladium metal catalyst, and 28g of formaldehyde solution (37wt.%) sequentially to a 250mL reactor (Yanzheng Instruments, YZQR-250(M)). Replace the gas inside the reactor three times with nitrogen (pressurizing to 1MPa each time and maintaining the pressure for 1min to check the airtightness). Set the mechanical stirring speed to 1000r·min. -1 When the temperature reaches 140℃, hydrogen gas is introduced until the pressure reaches 1 MPa. When the pressure drops to 0.9 MPa, hydrogen gas is added back to bring the pressure to 1 MPa, and the reaction is stopped when there is no significant pressure change within half an hour. After the reactor temperature drops to room temperature, the pressure inside the reactor is released, and the reaction solution is filtered. The filter cake is a palladium metal catalyst supported on sulfur-doped activated carbon. After the filtrate is distilled to remove moisture, the target product is quantitatively analyzed using a gas chromatograph (Agilent 7890B).

[0046] Example 2

[0047] 1. Preparation of palladium metal catalyst supported on sulfur-doped activated carbon:

[0048] (1) Dissolve 1.1659g Na2SO4 in 75mL deionized water, add 5g completely dry activated carbon (Maclean, 200 mesh, powder), stir thoroughly for 12h, then heat to 70℃ to evaporate the water, and obtain solid mixture A;

[0049] (2) The solid mixture A was placed in a vacuum oven and dried at 110 °C for 12 h; then placed in a tube furnace and calcined at 3 °C·min -1 -1 under argon atmosphere, and kept for 3 h, and cooled to room temperature to obtain the sulfur-doped activated carbon support CS5;

[0050] (3) 2 g of the sulfur-doped activated carbon support was added into 30 mL of deionized water, and stirred to disperse at room temperature for 1 h to obtain a suspension B; 0.1746 g of sodium tetrachloropalladate (98%) was added into 20 mL of deionized water, and 0.2 g of polyvinylpyrrolidone (K16-18) was added, and heated to 70 °C and kept for 1 h with stirring to obtain a solution C; then the suspension B was heated to 70 °C, and the solution C was added dropwise into the suspension B, and stirred for 5 h for impregnation;

[0051] (4) After sufficient impregnation by step (3), 0.1 g·mL -1 of aqueous potassium hydroxide solution was added into the suspension B to adjust the pH value of the suspension B to 8, and then stood for 1.5 h; then heated to 70 °C, and 10 mL of an aqueous solution containing 0.30 g of hydrazine hydrate was slowly added dropwise into the suspension B, and reduced for 1 h; the suspension B was cooled and suction filtered, and the filter cake was washed repeatedly with deionized water until the pH value of the filtrate was neutral; and the filter cake was placed in a vacuum oven and dried at 110 °C for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 3%Pd / CS5.

[0052] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method:

[0053] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of the sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of a formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time was pressurized to 1 MPa and kept for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 -1, and when the temperature was raised to 140 °C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was suction filtered. The filter cake was a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove water, and then subjected to quantitative analysis of the target product by a gas chromatograph (Agilent 7890B).

[0054] Example 3

[0055] 1. Preparation of a sulfur-doped activated carbon supported palladium metal catalyst:

[0056] (1) Dissolve 1.1659g Na2SO4 in 75mL deionized water, add 5g completely dry activated carbon (Maclean, 200 mesh, powder), stir thoroughly for 12h, then heat to 70℃ to evaporate the water, and obtain solid mixture A;

[0057] (2) Solid mixture A was placed in a vacuum oven and dried at 110°C for 12 h; then it was placed in a tube furnace and dried at 3°C·min under a helium atmosphere. -1 The temperature was raised to 600℃ and calcined for 3 hours. After cooling to room temperature, sulfur-doped activated carbon support CS5 was obtained.

[0058] (3) Add 2g of sulfur-doped activated carbon carrier to 30mL of deionized water and stir to disperse at room temperature for 1h to obtain suspension B; add 0.3296g of potassium tetrachloropalladium (98%) to 20mL of deionized water, add 0.2g of polyvinylpyrrolidone (K16-18), heat to 70℃ and stir for 1h to obtain solution C; then heat suspension B to 70℃, add solution C dropwise to suspension B, and stir to soak for 5h.

[0059] (4) After thorough soaking in step (3), add 0.1 g·mL -1 Ammonia solution was added to suspension B, the pH of suspension B was adjusted to 10, and then it was allowed to stand for 1.5 h. Then the temperature was raised to 70 °C, and 10 mL of aqueous solution containing 0.37 g sodium borohydride was slowly added dropwise to suspension B, and reduction was carried out for 1 h. Suspension B was cooled and filtered, and the filter cake was repeatedly washed with deionized water until the pH of the filtrate was neutral. The filter cake was placed in a vacuum oven and dried at 110 °C for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 5% Pd / CS5.

[0060] 2. Application of catalysts in the hydrogenation synthesis of 1,3-dimethyl-2-imidazolinone:

[0061] Add 12g of 2-imidazolium ketone, 100mL of deionized water, 0.6g of sulfur-doped activated carbon-supported palladium metal catalyst, and 28g of formaldehyde solution (37wt.%) sequentially to a 250mL reactor (Yanzheng Instruments, YZQR-250(M)). Replace the gas inside the reactor three times with nitrogen (pressurizing to 1MPa each time and maintaining the pressure for 1min to check the airtightness). Set the mechanical stirring speed to 1000r·min. -1When the temperature is raised to 140℃, hydrogen is introduced to a pressure of 1 MPa. When the pressure drops to 0.9 MPa, hydrogen is added to 1 MPa until the pressure does not change significantly within half an hour, and the reaction is stopped. When the kettle temperature drops to room temperature, the pressure in the kettle is emptied, and the reaction liquid is filtered. The filter cake is a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate is treated by distillation to remove moisture, and then the target product is quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0062] Example 4

[0063] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0064] (1) Dissolve 1.1659 g of Na2SO4 in 75 mL of deionized water, add 5 g of completely dried activated carbon (McLaren, 200 mesh, powder), stir thoroughly for 12 h, then heat to 70℃ to evaporate the water, and obtain solid mixture A;

[0065] (2) Place the solid mixture A in a vacuum oven and dry at 110℃ for 12 h; then place it in a tube furnace and calcine at 3℃·min -1 -1 to 600℃ under nitrogen atmosphere, and keep for 3 h. When it cools to room temperature, a sulfur-doped activated carbon support CS5 is obtained;

[0066] (3) Add 2 g of sulfur-doped activated carbon support to 30 mL of deionized water and stir to disperse at room temperature for 1 h to obtain suspension B; separately, add 1.2285 g of palladium nitrate (Pd 18.09 wt.%) to 20 mL of deionized water, add 0.2 g of polyvinylpyrrolidone (K16-18), heat to 70℃ and keep stirring for 1 h to obtain solution C; then heat the suspension B to 70℃, and add the solution C dropwise to the suspension B, and stir for 5 h;

[0067] (4) After sufficient impregnation according to step (3), add 0.1 g·mL -1 of sodium hydroxide aqueous solution to the suspension B to adjust the pH value of the suspension B to 11, and then stand for 1.5 h; then heat to 70℃, and slowly add 10 mL of aqueous solution containing 1.05 g of hydrazine hydrate to the suspension B, and reduce for 1 h; cool the suspension B, filter, and wash the filter cake with deionized water repeatedly until the pH of the filtrate is neutral; place the filter cake in a vacuum oven and dry at 110℃ for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 10%Pd / CS5.

[0068] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method:

[0069] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the kettle was replaced with nitrogen gas three times (each time pressurized to 1 MPa and maintained for 1 min to check the air tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was raised to 140°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered. The filter cake was sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove water, and then the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0070] Table 1 Effect of theoretical loading of palladium on catalyst performance

[0071] Theoretical loading of palladium Conversion (%) Selectivity (%) Reaction length (h) Example 1 7.5% Pd >99.99 99.95 3.60 Example 2 3% Pd 98.47 99.02 6.91 Example 3 5% Pd 99.53 99.21 5.35 Example 4 10% Pd >99.99 99.87 3.42 Comparative Example 1 1% Pd 95.87 69.33 13.03

[0072] Example 5

[0073] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0074] (1) 0.4521 g of Na2SO4 was dissolved in 75 mL of deionized water, 5 g of completely dried activated carbon (Macklin, 200 mesh, powder) was added, and stirred for 12 h, then heated to 70°C to evaporate the water, to obtain solid mixture A;

[0075] (2) Solid mixture A was placed in a vacuum oven and dried at 110°C for 12 h; then placed in a tube furnace and calcined at 3°C·min -1 -1 to 600°C under argon atmosphere, and kept for 3 h, and cooled to room temperature to obtain sulfur-doped activated carbon support CS2;

[0076] (3) 2 g of sulfur-doped activated carbon support was added to 30 mL of deionized water and stirred at room temperature for 1 h to obtain suspension B; 0.3818 g of dichlorotetraammine palladium (98%) was added to 20 mL of deionized water, 0.2 g of polyvinylpyrrolidone (K16-18) was added, and heated to 70°C for 1 h with stirring to obtain solution C; then suspension B was heated to 70°C, and solution C was added dropwise to suspension B, and stirred for 5 h;

[0077] (4) After sufficient impregnation by step (3), 0.1 g·mL -1hydrogenated to 70 °C, 10 mL of an aqueous solution containing 0.58 g of sodium borohydride was slowly added to the suspension B, and reduced for 1 h; the suspension B was cooled, suction filtered, and the filter cake was washed repeatedly with deionized water until the filtrate was neutral; the filter cake was placed in a vacuum oven and dried at 110 °C for 9 h to obtain the sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS2.

[0078] 2. Use of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolinone by hydrogenation method:

[0079] Into a 250 mL reaction kettle (Yanzheng Instruments, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time pressurized to 1 MPa and maintained for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was raised to 140 °C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, the reaction liquid was suction filtered, and the filter cake was sulfur-doped activated carbon supported palladium metal catalyst. After removing the water from the filtrate by distillation, the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0080] Example 6

[0081] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0082] (1) 0.6851 g of Na2SO4 was dissolved in 75 mL of deionized water, 5 g of completely dried activated carbon (Macklin, 200 mesh, powder) was added, stirred thoroughly for 12 h, and then heated to 70 °C to evaporate the water, obtaining a solid mixture A;

[0083] (2) The solid mixture A was placed in a vacuum oven and dried at 110 °C for 12 h; then placed in a tube furnace and calcined at 3 °C·min -1 to 600 °C under a helium atmosphere, and maintained for 3 h. After cooling to room temperature, a sulfur-doped activated carbon support CS3 was obtained;

[0084] (3) 2 g of sulfur-doped activated carbon support was added to 30 mL of deionized water, stirred and dispersed at room temperature for 1 h to obtain a suspension B; another 8.1 mL of aqueous tetrachloropalladate solution (Pd 0.02 g·mL -1) into 20 mL of deionized water, 0.2 g of polyvinylpyrrolidone (K16-18) was added, heated to 70 °C and kept stirring for 1 h to obtain solution C; then the suspension B was heated to 70 °C, solution C was added dropwise into the suspension B, and the impregnation was kept stirring for 5 h;

[0085] (4) After sufficient impregnation in step (3), 0.1 g mL -1 of ammonia solution was added into the suspension B to adjust the pH value of the suspension B to 8, and then it was left to stand for 1.5 h; then it was heated to 70 °C, and 10 mL of an aqueous solution containing 0.77 g of hydrazine hydrate was slowly added dropwise into the suspension B, and the reduction was kept for 1 h; the suspension B was cooled and suction filtered, and the filter cake was washed repeatedly with deionized water until the filtrate was neutral; the filter cake was dried in a vacuum oven at 110 °C for 9 h to obtain the sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS3.

[0086] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method:

[0087] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and kept for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r min -1 When the temperature was increased to 140 °C, hydrogen was introduced to a pressure of 1 MPa. When the pressure decreased to 0.9 MPa, hydrogen was added to 1 MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature decreased to room temperature, the pressure in the kettle was emptied, the reaction solution was suction filtered, and the filter cake was the sulfur-doped activated carbon supported palladium metal catalyst. After removing the water from the filtrate by distillation, the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0088] Example 7

[0089] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0090] (1) 0.9230 g of Na2SO4 was dissolved in 75 mL of deionized water, 5 g of completely dried activated carbon (Macklin, 200 mesh, powder) was added, and stirred thoroughly for 12 h, and then heated to 70 °C to evaporate the water to obtain solid mixture A;

[0091] (2) The solid mixture A was placed in a vacuum oven and dried at 110 °C for 12 h; then it was placed in a tube furnace and dried at a rate of 3 °C min -1Rise to 600 ℃ for calcination, and keep 3 h, wait to cool to room temperature, get sulfur doped activated carbon carrier CS4;

[0092] (3) 2 g of sulfur-doped activated carbon carrier was added to 30 mL of deionized water, and stirred and dispersed at room temperature for 1 h to obtain a suspension B; 0.4576 g of sodium tetrachloropalladate (98%) was added to 20 mL of deionized water, and 0.2 g of polyvinylpyrrolidone (K16-18) was added, heated to 70 ℃ and kept stirring for 1 h to obtain a solution C; then the suspension B was heated to 70 ℃, and the solution C was added dropwise to the suspension B, and stirred and impregnated for 5 h;

[0093] (4) After sufficient impregnation in step (3), 0.1 g·mL -1 deionized water was added to the suspension B to adjust the pH value of the suspension B to 10, and then it was left to stand for 1.5 h; then it was heated to 70 ℃, and 10 mL of an aqueous solution containing 0.58 g of sodium borohydride was slowly added dropwise to the suspension B, and reduced for 1 h; the suspension B was cooled, suction filtered, and the filter cake was repeatedly washed with deionized water until the filtrate was neutral; the filter cake was placed in a vacuum oven and dried at 110 ℃ for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS4.

[0094] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method:

[0095] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250 (M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and kept for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was increased to 140 ℃, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, the reaction liquid was suction filtered, and the filter cake was a sulfur-doped activated carbon supported palladium metal catalyst. After removing the water from the filtrate by distillation, the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0096] Example 8

[0097] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0098] (1) Dissolve 1.4140 g Na2SO4 in 75 mL deionized water, add 5 g completely dry activated carbon (Mcclin, 200 mesh, powder), stir well for 12 h, then heat to 70 °C to evaporate water, and obtain solid mixture A;

[0099] (2) Dry solid mixture A in a vacuum oven at 110 °C for 12 h, then calcine in a tube furnace under argon atmosphere at a rate of 3 °C·min -1 to 600 °C for 3 h, and keep the temperature for 3 h, and then cool to room temperature to obtain sulfur-doped activated carbon support CS6;

[0100] (3) Add 2 g sulfur-doped activated carbon support into 30 mL deionized water, and stir to disperse at room temperature for 1 h to obtain suspension B; add 0.5077 g potassium tetrachloropalladate (98%) into 20 mL deionized water, and add 0.2 g polyvinylpyrrolidone (K16-18), heat to 70 °C, and keep stirring for 1 h to obtain solution C; then heat suspension B to 70 °C, and add solution C dropwise into suspension B, and stir to impregnate for 5 h;

[0101] (4) After impregnation in step (3), add 0.1 g·mL -1 of aqueous potassium hydroxide solution into suspension B to adjust the pH value of suspension B to 11, and then stand for 1.5 h; then heat to 70 °C, and slowly drop 10 mL aqueous solution containing 0.77 g hydrazine hydrate into suspension B, and reduce for 1 h; cool suspension B, and suction filter, and wash the filter cake with deionized water repeatedly until the pH value of the filtrate is neutral; and dry the filter cake in a vacuum oven at 110 °C for 9 h to obtain sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS6.

[0102] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method:

[0103] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250 (M)), sequentially add 12 g 2-imidazolidinone, 100 mL deionized water, 0.6 g sulfur-doped activated carbon supported palladium metal catalyst, and 28 g formaldehyde solution (37 wt.%), and replace the gas in the kettle with nitrogen three times (each time pressurize to 1 MPa and keep for 1 min to check the air tightness of the device). Set the mechanical stirring rate to 1000 r·min -1When the temperature is raised to 140℃, hydrogen is introduced to a pressure of 1 MPa. When the pressure drops to 0.9 MPa, hydrogen is added to 1 MPa until the pressure does not change significantly within half an hour, and the reaction is stopped. When the kettle temperature drops to room temperature, the pressure in the kettle is emptied, and the reaction liquid is filtered. The filter cake is a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate is treated by distillation to remove moisture, and then the target product is quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0104] Example 9

[0105] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0106] (1) Dissolve 1.6674 g of Na2SO4 in 75 mL of deionized water, add 5 g of completely dried activated carbon (McLin, 200 mesh, powder), stir thoroughly for 12 h, then heat to 70℃ to evaporate the water, and obtain solid mixture A;

[0107] (2) Place the solid mixture A in a vacuum oven and dry at 110℃ for 12 h; then place it in a tube furnace and calcine at 3℃·min -1 -1 to 600℃ under a helium atmosphere, and keep for 3 h. When it cools to room temperature, a sulfur-doped activated carbon support CS7 is obtained;

[0108] (3) Add 2 g of sulfur-doped activated carbon support to 30 mL of deionized water and stir to disperse at room temperature for 1 h to obtain a suspension B; separately, add 0.8965 g of palladium nitrate (Pd 18.09 wt.%) to 20 mL of deionized water, add 0.2 g of polyvinylpyrrolidone (K16-18), heat to 70℃ and keep stirring for 1 h to obtain a solution C; then heat the suspension B to 70℃, and add the solution C dropwise to the suspension B, and stir for 5 h;

[0109] (4) After sufficient impregnation according to step (3), add 0.1 g·mL -1 of ammonia solution to the suspension B to adjust the pH of the suspension B to 9, and then stand for 1.5 h; then heat to 70℃, slowly add 10 mL of an aqueous solution containing 0.58 g of sodium borohydride to the suspension B, and reduce for 1 h; cool the suspension B, filter, and wash the filter cake with deionized water until the pH of the filtrate is neutral; place the filter cake in a vacuum oven and dry at 110℃ for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 7.5% Pd / CS7.

[0110] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method:

[0111] A 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)) was sequentially charged with 12 g of 2-imidazolidone, 100 mL of deionized water, 0.6 g of a sulfur-doped activated carbon-supported palladium metal catalyst, 28 g of a formaldehyde solution (37 wt.%), and the kettle was purged with nitrogen three times (each time pressurized to 1 MPa and maintained for 1 min to check the air tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was raised to 140°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa, until there was no significant change in pressure within half an hour, and the reaction was stopped. When the kettle temperature dropped to room temperature, the pressure in the kettle was evacuated, and the reaction liquid was filtered. The filter cake was a sulfur-doped activated carbon-supported palladium metal catalyst, and the filtrate was treated by distillation to remove water, and then the target product was quantitatively analyzed by gas chromatography (Agilent 7890B).

[0112] Table 2 Effect of theoretical doping amount of sulfur on catalyst performance

[0113] Theoretical doping of sulfur Conversion (%) Selectivity (%) Reaction length (h) Example 1 5％ >99.99 99.95 3.60 Example 5 2％ 99.82 99.31 6.35 Example 6 3％ 99.11 98.34 5.30 Example 7 4％ 98.34 99.46 4.31 Example 8 6％ >99.99 99.93 3.58 Example 9 7％ >99.99 99.24 3.47 Comparative Example 2 1％ 97.25 98.72 8.43 Comparative Example 3 0％ 92.74 88.65 13.08

[0114] Example 10

[0115] 1. Preparation of a sulfur-doped activated carbon-supported palladium metal catalyst:

[0116] (1) 1.1659 g of Na2SO4 was dissolved in 75 mL of deionized water, 5 g of completely dried activated carbon (Macklin, 200 mesh, powder) was added, stirred thoroughly for 12 h, and then heated to 70°C to evaporate the water, obtaining a solid mixture A;

[0117] (2) The solid mixture A was placed in a vacuum oven and dried at 110°C for 12 h; then placed in a tube furnace and calcined at 3°C·min -1 -1 to 500°C under a nitrogen atmosphere, and maintained for 3 h, and then cooled to room temperature to obtain a sulfur-doped activated carbon support CS5;

[0118] (3) 2 g of the sulfur-doped activated carbon support was added to 30 mL of deionized water, stirred at room temperature for 1 h to obtain a suspension B; 0.3818 g of dichlorotetraammine palladium (98%) was added to 20 mL of deionized water, 0.2 g of polyvinylpyrrolidone (K16-18) was added, heated to 70°C and maintained for 1 h with stirring to obtain a solution C; then the suspension B was heated to 70°C, and the solution C was added dropwise to the suspension B, and stirred for 5 h;

[0119] (4) After sufficient impregnation according to step (3), 0.1 g·mL -1hydrogen peroxide solution (30 wt.%) was added into the suspension B slowly dropwise, and the pH value of the suspension B was adjusted to 8.5. The suspension B was heated to 70 °C, and 10 mL of an aqueous solution containing 0.77 g of hydrazine hydrate was added slowly dropwise into the suspension B. The reduction was carried out for 1 h. The suspension B was cooled, and the filter cake was washed with deionized water until the pH value of the filtrate was neutral. The filter cake was dried in a vacuum oven at 110 °C for 9 h to obtain the sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS5.

[0120] 2. Use of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolinone by hydrogenation method:

[0121] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added. The gas in the kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and maintained for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was increased to 140 °C, hydrogen was introduced to a pressure of 1 MPa. When the pressure decreased to 0.9 MPa, hydrogen was added to 1 MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature decreased to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered. The filter cake was the sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove water, and then the target product was quantitatively analyzed by gas chromatography (Agilent 7890B).

[0122] Example 11

[0123] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0124] (1) 1.1659 g of Na2SO4 was dissolved in 75 mL of deionized water, 5 g of completely dried activated carbon (Macklin, 200 mesh, powder) was added, and stirred for 12 h. Then the water was evaporated by heating to 70 °C to obtain a solid mixture A;

[0125] (2) The solid mixture A was placed in a vacuum oven and dried at 110 °C for 12 h. Then it was placed in a tube furnace and calcined at 3 °C·min -1 -1 under argon atmosphere to 700 °C for 3 h, and cooled to room temperature to obtain the sulfur-doped activated carbon support CS5;

[0126] (3) 2 g of the sulfur-doped activated carbon support was added to 30 mL of deionized water and stirred at room temperature for 1 h to obtain a suspension B. Separately, 8.1 mL of an aqueous solution of tetrachloropalladate (Pd 0.02 g·mL -1) into 20 mL of deionized water, 0.2 g of polyvinylpyrrolidone (K16-18) was added, heated to 70 °C and kept stirring for 1 h to obtain solution C; then the suspension B was heated to 70 °C, solution C was added dropwise into the suspension B, and the impregnation was kept stirring for 5 h;

[0127] (4) After sufficient impregnation in step (3), 0.1 g mL -1 potassium hydroxide aqueous solution was added into the suspension B to adjust the pH value of the suspension B to 10, and then it was left to stand for 1.5 h; then it was heated to 70 °C, and 10 mL of an aqueous solution containing 0.58 g of sodium borohydride was slowly added dropwise into the suspension B, and the reduction was kept for 1 h; the suspension B was cooled, and then filtered under suction, and the filter cake was washed repeatedly with deionized water until the pH value of the filtrate was neutral; the filter cake was dried in a vacuum oven at 110 °C for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS5.

[0128] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolinone by hydrogenation method:

[0129] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of a sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of a formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and kept for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r min -1 When the temperature was increased to 140 °C, hydrogen was introduced to a pressure of 1 MPa. When the pressure decreased to 0.9 MPa, hydrogen was added to 1 MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature decreased to room temperature, the pressure in the kettle was emptied, the reaction solution was filtered under suction, and the filter cake was a sulfur-doped activated carbon supported palladium metal catalyst. After removing the water from the filtrate by distillation, the target product was quantitatively analyzed by a gas chromatograph (Agilent 7890B).

[0130] Example 12

[0131] 1. Preparation of a sulfur-doped activated carbon supported palladium metal catalyst:

[0132] (1) 1.1659 g of Na2SO4 was dissolved in 75 mL of deionized water, 5 g of completely dried activated carbon (Macklin, 200 mesh, powder) was added, and the mixture was stirred thoroughly for 12 h, and then heated to 70 °C to evaporate the water to obtain a solid mixture A;

[0133] (2) The solid mixture A was placed in a vacuum oven and dried at 110 °C for 12 h; then it was placed in a tube furnace and dried at a rate of 3 °C min -1Rise to 800℃ for calcination, and keep for 3h, wait to cool to room temperature, get sulfur-doped activated carbon carrier CS5;

[0134] (3) 2g of sulfur-doped activated carbon carrier was added to 30mL of deionized water, stirred and dispersed at room temperature for 1h to obtain a suspension B; 0.4576g of sodium tetrachloropalladate (98%) was added to 20mL of deionized water, 0.2g of polyvinylpyrrolidone (K16-18) was added, heated to 70℃ and kept stirring for 1h to obtain a solution C; then the suspension B was heated to 70℃, the solution C was added dropwise to the suspension B, and the impregnation was stirred for 5h;

[0135] (4) After sufficient impregnation in step (3), 0.1g·mL -1 of ammonia solution was added to the suspension B to adjust the pH value of the suspension B to 11, and then it was left to stand for 1.5h; then it was heated to 70℃, 10mL of an aqueous solution containing 0.77g of hydrazine hydrate was slowly added dropwise to the suspension B, and reduced for 1h; the suspension B was cooled, suction filtered, and the filter cake was washed repeatedly with deionized water until the filtrate was neutral; the filter cake was placed in a vacuum oven and dried at 110℃ for 9h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS5.

[0136] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method:

[0137] Into a 250mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12g of 2-imidazolidinone, 100mL of deionized water, 0.6g of sulfur-doped activated carbon supported palladium metal catalyst, and 28g of formaldehyde solution (37wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time the pressure was increased to 1MPa and kept for 1min to check the gas tightness of the device). The mechanical stirring rate was set to 1000r·min -1 When the temperature was raised to 140℃, hydrogen was introduced to a pressure of 1MPa. When the pressure dropped to 0.9MPa, hydrogen was added to 1MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, the reaction liquid was suction filtered, and the filter cake was a sulfur-doped activated carbon supported palladium metal catalyst. After removing the water from the filtrate by distillation, the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0138] Table 3 Effect of calcination temperature of the carrier on the performance of the catalyst

[0139] Calcination temperature of support Conversion (%) Selectivity (%) Reaction length (h) Example 1 600℃ >99.99 99.95 3.60 Example 10 500℃ 98.56 98.20 4.67 Example 11 700℃ 99.35 99.23 3.51 Example 12 800℃ 97.38 98.29 4.18 Comparative Example 4 400℃ 97.62 90.14 9.03 Comparative Example 5 Not calcined 98.30 99.27 13.08

[0140] Example 13

[0141] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0142] (1) Dissolve 1.1659 g Na2SO4 in 75 mL deionized water, add 5 g completely dried activated carbon (Mcclin, 200 mesh, powder), stir well for 12 h, then heat to 70 °C to evaporate water, and obtain solid mixture A;

[0143] (2) Dry solid mixture A in a vacuum oven at 110 °C for 12 h, then place it in a tube furnace, calcine at 3 °C·min -1

[0144] (3) Add 2 g sulfur-doped activated carbon support into 30 mL deionized water, stir to disperse at room temperature for 1 h, and obtain suspension B; add 0.5077 g potassium tetrachloropalladate (98%) into 20 mL deionized water, add 0.1 g polyvinylpyrrolidone (K16-18), heat to 70 °C, and keep stirring for 1 h to obtain solution C; then heat suspension B to 70 °C, and add solution C dropwise into suspension B, and stir to impregnate for 5 h;

[0145] (4) After sufficient impregnation in step (3), add 0.1 g·mL -1

[0146] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method:

[0147] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250 (M)), add 12 g 2-imidazolidinone, 100 mL deionized water, 0.6 g sulfur-doped activated carbon supported palladium metal catalyst, and 28 g formaldehyde solution (37 wt.%) in sequence, replace the gas in the kettle with nitrogen three times (each time pressurize to 1 MPa and keep for 1 min to check the air tightness of the device). Set the mechanical stirring rate to 1000 r·min -1 ​​When the temperature is raised to 140℃, hydrogen is introduced to a pressure of 1 MPa. When the pressure drops to 0.9 MPa, hydrogen is added to 1 MPa until the pressure does not change significantly within half an hour, and the reaction is stopped. When the kettle temperature drops to room temperature, the pressure in the kettle is emptied, and the reaction liquid is filtered. The filter cake is a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate is treated by distillation to remove moisture, and then the target product is quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0148] Example 14

[0149] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0150] (1) Dissolve 1.1659 g of Na2SO4 in 75 mL of deionized water, add 5 g of completely dried activated carbon (McLaren, 200 mesh, powder), stir thoroughly for 12 h, then heat to 70℃ to evaporate the water, and obtain solid mixture A;

[0151] (2) Place the solid mixture A in a vacuum oven and dry at 110℃ for 12 h; then place it in a tube furnace and calcine at 3℃·min -1 -600℃ under argon atmosphere, and keep for 3 h. When it cools to room temperature, a sulfur-doped activated carbon support CS5 is obtained;

[0152] (3) Add 2 g of sulfur-doped activated carbon support to 30 mL of deionized water, and stir to disperse at room temperature for 1 h to obtain suspension B; separately, add 0.8965 g of palladium nitrate (Pd 18.09 wt.%) to 20 mL of deionized water, add 0.2 g of polyethylene glycol (Mn800), heat to 70℃ and keep stirring for 1 h to obtain solution C; then heat the suspension B to 70℃, and add the solution C dropwise to the suspension B, and stir for 5 h;

[0153] (4) After sufficient impregnation in step (3), add 0.1 g·mL -1 of potassium hydroxide aqueous solution to the suspension B to adjust the pH value of the suspension B to 8, and then stand for 1.5 h; then heat to 70℃, and slowly add 10 mL of aqueous solution containing 0.77 g of hydrazine hydrate to the suspension B, and reduce for 1 h; cool the suspension B, filter, and wash the filter cake with deionized water until the filtrate is neutral; place the filter cake in a vacuum oven and dry at 110℃ for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS5.

[0154] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolinone by hydrogenation method:

[0155] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the kettle was replaced with nitrogen gas three times (each time pressurized to 1 MPa and maintained for 1 min to check the air tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was raised to 140°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature dropped to room temperature, the pressure in the kettle was evacuated, and the reaction liquid was filtered. The filter cake was sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove water, and then the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0156] Example 15

[0157] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0158] (1) Dissolve 1.1659 g of Na2SO4 in 75 mL of deionized water, add 5 g of completely dried activated carbon (Macklin, 200 mesh, powder), stir thoroughly for 12 h, then heat to 70°C to evaporate the water, and obtain solid mixture A;

[0159] (2) Place the solid mixture A in a vacuum oven and dry at 110°C for 12 h; then place it in a tube furnace and calcine at 3°C·min -1 to 600°C under a helium atmosphere, and maintain for 3 h. After cooling to room temperature, obtain the sulfur-doped activated carbon support CS5;

[0160] (3) Add 2 g of sulfur-doped activated carbon support to 30 mL of deionized water, and stir to disperse at room temperature for 1 h to obtain suspension B; separately, add 0.3818 g of dichlorotetraammine palladium (98%) to 20 mL of deionized water, add 0.1 g of polyethylene glycol (Mn800), heat to 70°C and maintain stirring for 1 h to obtain solution C; then heat the suspension B to 70°C, and add the solution C dropwise to the suspension B, and stir for 5 h;

[0161] (4) After sufficient impregnation by step (3), add 0.1 g·mL -1Ammonia solution was added to suspension B, and the pH of suspension B was adjusted to 10. The suspension was then allowed to stand for 1.5 h. Subsequently, the temperature was raised to 70 °C, and 10 mL of an aqueous solution containing 0.58 g of sodium borohydride was slowly added dropwise to suspension B, and the suspension was reduced for 1 h. Suspension B was cooled and filtered, and the filter cake was repeatedly washed with deionized water until the pH of the filtrate was neutral. The filter cake was placed in a vacuum oven and dried at 110 °C for 9 h to obtain a 7.5% Pd / CS5 palladium metal catalyst supported on sulfur-doped activated carbon.

[0162] 2. Application of catalysts in the hydrogenation synthesis of 1,3-dimethyl-2-imidazolinone:

[0163] Add 12g of 2-imidazolium ketone, 100mL of deionized water, 0.6g of sulfur-doped activated carbon-supported palladium metal catalyst, and 28g of formaldehyde solution (37wt.%) sequentially to a 250mL reactor (Yanzheng Instruments, YZQR-250(M)). Replace the gas inside the reactor three times with nitrogen (pressurizing to 1MPa each time and maintaining the pressure for 1min to check the airtightness). Set the mechanical stirring speed to 1000r·min. -1 When the temperature reaches 140℃, hydrogen gas is introduced until the pressure reaches 1 MPa. When the pressure drops to 0.9 MPa, hydrogen gas is added back to bring the pressure to 1 MPa, and the reaction is stopped when there is no significant pressure change within half an hour. After the reactor temperature drops to room temperature, the pressure inside the reactor is released, and the reaction solution is filtered. The filter cake is a palladium metal catalyst supported on sulfur-doped activated carbon. After the filtrate is distilled to remove moisture, the target product is quantitatively analyzed using a gas chromatograph (Agilent 7890B).

[0164] Table 4. Effect of dispersant on catalyst performance

[0165]

[0166]

[0167] Example 16

[0168] 1. Preparation of palladium metal catalyst supported on sulfur-doped activated carbon:

[0169] (1) Dissolve 1.9715g Na2S·9H2O in 75mL of deionized water, add 5g of completely dry activated carbon (Maclean, 200 mesh, powder), stir thoroughly for 12h, then heat to 70℃ to evaporate the water, and obtain solid mixture A;

[0170] (2) Solid mixture A was placed in a vacuum oven and dried at 110°C for 12 h; then it was placed in a tube furnace and dried at 3°C·min under a nitrogen atmosphere. -1 The temperature was raised to 600℃ and calcined for 3 hours. After cooling to room temperature, sulfur-doped activated carbon support CS5 was obtained.

[0171] (3) 2 g of sulfur-doped activated carbon support was added into 30 mL of deionized water, and stirred to disperse at room temperature for 1 h to obtain a suspension B; 8.1 mL of an aqueous solution of tetrachloropalladium acid (Pd 0.02 g·mL -1 ) was added into 20 mL of deionized water, 0.2 g of polyvinylpyrrolidone (K16-18) was added, and heated to 70°C for 1 h with stirring to obtain a solution C; then the suspension B was heated to 70°C, and the solution C was added dropwise into the suspension B, and stirred for 5 h for impregnation;

[0172] (4) After sufficient impregnation according to step (3), 0.1 g·mL -1 of an aqueous solution of sodium hydroxide was added into the suspension B to adjust the pH value of the suspension B to 11, and then stood for 1.5 h; then heated to 70°C, and 10 mL of an aqueous solution containing 0.77 g of hydrazine hydrate was slowly added dropwise into the suspension B, and reduced for 1 h; the suspension B was cooled, and suction filtered, and the filter cake was washed repeatedly with deionized water until the pH value of the filtrate was neutral; the filter cake was placed in a vacuum oven, and dried at 110°C for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS5.

[0173] 2. Application of the catalyst in synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method:

[0174] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250 (M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen for three times (each time was pressurized to 1 MPa and kept for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 , and when the temperature was increased to 140°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure decreased to 0.9 MPa, hydrogen was added to 1 MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature decreased to room temperature, the pressure in the kettle was emptied, the reaction liquid was suction filtered, and the filter cake was the sulfur-doped activated carbon supported palladium metal catalyst. After the water in the filtrate was removed by distillation treatment, the target product was quantitatively analyzed by a gas chromatograph (Agilent 7890B).

[0175] Example 17

[0176] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0177] (1) 0.8542 g NaHSO3 was dissolved in 75 mL deionized water, 5 g completely dried activated carbon (Macklin, 200 mesh, powder) was added, stirred thoroughly for 12 h, and then heated to 70 °C to evaporate water, obtaining solid mixture A;

[0178] (2) Solid mixture A was dried in a vacuum oven at 110 °C for 12 h, and then calcined in a tube furnace under argon atmosphere at a rate of 3 °C·min -1 to 600 °C for 3 h, and then cooled to room temperature, obtaining sulfur-doped activated carbon support CS5;

[0179] (3) 2 g sulfur-doped activated carbon support was added to 30 mL deionized water, and stirred at room temperature for 1 h to obtain suspension B; 0.4576 g sodium tetrachloropalladate (98%) was added to 20 mL deionized water, and 0.2 g polyvinylpyrrolidone (K16-18) was added, heated to 70 °C and stirred for 1 h to obtain solution C; then suspension B was heated to 70 °C, and solution C was added dropwise to suspension B, and stirred for 5 h;

[0180] (4) After sufficient impregnation in step (3), 0.1 g·mL -1 aqueous potassium hydroxide solution was added to suspension B to adjust the pH of suspension B to 9, and then stood for 1.5 h; then heated to 70 °C, and 10 mL aqueous solution containing 0.58 g sodium borohydride was slowly added dropwise to suspension B, and reduced for 1 h; suspension B was cooled, suction filtered, and the filter cake was washed repeatedly with deionized water until the filtrate was neutral; the filter cake was dried in a vacuum oven at 110 °C for 9 h, obtaining sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS5.

[0181] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method:

[0182] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g 2-imidazolidinone, 100 mL deionized water, 0.6 g sulfur-doped activated carbon supported palladium metal catalyst, and 28 g formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time pressurized to 1 MPa and maintained for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1When the temperature was raised to 140°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa until there was no significant change in pressure within half an hour, and the reaction was stopped. After the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered. The filter cake was a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove moisture, and then quantitative analysis of the target product was performed using a gas chromatograph (Agilent 7890B).

[0183] Table 5 Influence of sulfur atom precursor on catalyst performance

[0184] Sulfur atom precursor Conversion (%) Selectivity (%) Reaction length (h) Example 1 Na2SO4 >99.99 99.95 3.60 Example 16 Na2S >99.99 99.90 3.71 Example 17 NaHSO3 >99.99 99.28 5.07 Comparative Example 3 None 92.74 88.65 13.08

[0185] Example 18

[0186] Example 18 investigated the application of the catalyst prepared in Example 1 in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation at different reaction temperatures.

[0187] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added. The kettle was replaced with nitrogen three times (each time pressurized to 1 MPa and kept for 1 min to check the air tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was raised to 150°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa until there was no significant change in pressure within half an hour, and the reaction was stopped. After the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered. The filter cake was a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove moisture, and then quantitative analysis of the target product was performed using a gas chromatograph (Agilent 7890B).

[0188] Example 19

[0189] Example 19 investigated the application of the catalyst prepared in Example 1 in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation at different reaction temperatures.

[0190] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added. The kettle was replaced with nitrogen three times (each time pressurized to 1 MPa and kept for 1 min to check the air tightness of the device). The mechanical stirring rate was set to 1000 r·min -1When the temperature was raised to 160°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa until there was no significant change in pressure within half an hour, and the reaction was stopped. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered. The filter cake was a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove moisture, and then the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0191] Example 20

[0192] Example 20 investigates the application of the catalyst prepared in Example 1 in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method under different reaction pressures.

[0193] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added. The kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and maintained for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was raised to 140°C, hydrogen was introduced to a pressure of 1.5 MPa. When the pressure dropped to 1.4 MPa, hydrogen was added to 1 MPa until there was no significant change in pressure within half an hour, and the reaction was stopped. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered. The filter cake was a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove moisture, and then the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0194] Example 21

[0195] Example 21 investigates the application of the catalyst prepared in Example 1 in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method under different reaction pressures.

[0196] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added. The kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and maintained for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1When the temperature was raised to 140°C, hydrogen was introduced to a pressure of 2 MPa. When the pressure dropped to 1.9 MPa, hydrogen was added to 1 MPa until the pressure did not change significantly within half an hour, and the reaction was stopped. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered, the filter cake was a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove moisture, and then the target product was quantitatively analyzed by a gas chromatograph (Agilent 7890B).

[0197] Table 6 Effect of reaction conditions on the synthesis of 1,3-dimethyl-2-imidazolinone by hydrogenation method

[0198]

[0199]

[0200] Example 22

[0201] Example 22 investigated the reuse performance of the catalyst prepared in Example 1 in the synthesis of 1,3-dimethyl-2-imidazolinone by hydrogenation method.

[0202] Into a 250 mL reaction kettle (Yizheng Instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and maintained for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was raised to 140°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa until the pressure did not change significantly within half an hour, and the reaction was stopped. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered, the filter cake was a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove moisture, and then the target product was quantitatively analyzed by a gas chromatograph (Agilent 7890B). The catalyst after the reaction was continuously reused, and 0.03 g of fresh catalyst prepared in Example 1 was added before each feeding. The experimental conditions were the same, and the experimental results are shown in Table 7.

[0203] Table 7 Reuse performance of sulfur-doped activated carbon supported palladium metal catalyst

[0204] Number of reactions Conversion (%) Selectivity (%) Reaction length (h) 1 >99.99 99.78 3.60 2 >99.99 99.59 5.23 3 99.41 99.66 5.87 4 99.80 99.63 6.03 5 99.84 99.87 6.25 6 98.72 99.35 6.20 7 99.78 99.63 6.67 8 99.46 99.71 6.90 9 99.82 99.48 7.21 10 99.63 98.50 7.04

[0205] Comparative Example 1

[0206] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0207] (1) Dissolve 1.1659 g Na2SO4 in 75 mL deionized water, add 5 g completely dried activated carbon (Mcclin, 200 mesh, powder), stir well for 12 h, then heat to 70 °C to evaporate water, and obtain solid mixture A;

[0208] (2) Dry solid mixture A in a vacuum oven at 110 °C for 12 h, then place it in a tube furnace, calcine at 3 °C·min -1 to 600 °C under nitrogen atmosphere, and keep for 3 h, and obtain sulfur-doped activated carbon support CS5 after cooling to room temperature;

[0209] (3) Add 2 g sulfur-doped activated carbon support into 30 mL deionized water, and stir to disperse at room temperature for 1 h, and obtain suspension B; add 1.0 mL aqueous solution of tetrachloropalladium acid (Pd 0.02 g·mL -1 ) into 20 mL deionized water, add 0.2 g polyvinylpyrrolidone (K16-18), heat to 70 °C, and keep stirring for 1 h to obtain solution C; then heat suspension B to 70 °C, and add solution C dropwise into suspension B, and stir to impregnate for 5 h;

[0210] (4) After sufficient impregnation in step (3), add 0.1 g·mL -1 aqueous solution of sodium hydroxide into suspension B to adjust the pH value of suspension B to 9, and then stand for 1.5 h; then heat to 70 °C, and slowly drop 10 mL aqueous solution containing 0.07 g sodium borohydride into suspension B, and reduce for 1 h; cool suspension B, and suction filter, and wash the filter cake with deionized water repeatedly until the pH value of the filtrate is neutral; and dry the filter cake in a vacuum oven at 110 °C for 9 h to obtain sulfur-doped activated carbon supported palladium metal catalyst 1%Pd / CS5.

[0211] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method:

[0212] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), sequentially add 12 g 2-imidazolidinone, 100 mL deionized water, 0.6 g sulfur-doped activated carbon supported palladium metal catalyst, and 28 g formaldehyde solution (37 wt.%), and replace the gas in the kettle with nitrogen three times (each time pressurize to 1 MPa and keep for 1 min to check the air tightness of the device). Set the mechanical stirring rate to 1000 r·min -1When the temperature is raised to 140℃, hydrogen is introduced to a pressure of 1 MPa. When the pressure drops to 0.9 MPa, hydrogen is added to 1 MPa until the pressure does not change significantly within half an hour, and the reaction is stopped. When the kettle temperature drops to room temperature, the pressure in the kettle is emptied, and the reaction liquid is filtered. The filter cake is a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate is treated by distillation to remove moisture, and then the target product is quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0213] Comparative Example 2

[0214] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0215] (1) Dissolve 0.2238 g of Na2SO4 in 75 mL of deionized water, add 5 g of completely dried activated carbon (McLaren, 200 mesh, powder), stir thoroughly for 12 h, then heat to 70℃ to evaporate the water, and obtain solid mixture A;

[0216] (2) Place the solid mixture A in a vacuum oven and dry at 110℃ for 12 h; then place it in a tube furnace and calcine at 3℃·min -1 -1 to 600℃ under argon atmosphere, and keep for 3 h. When it cools to room temperature, a sulfur-doped activated carbon support CS1 is obtained;

[0217] (3) Add 2 g of sulfur-doped activated carbon support to 30 mL of deionized water, and stir to disperse at room temperature for 1 h to obtain a suspension B; separately, add 0.4576 g of sodium tetrachloropalladate (98%) to 20 mL of deionized water, add 0.2 g of polyvinylpyrrolidone (K16-18), heat to 70℃ and keep stirring for 1 h to obtain a solution C; then heat the suspension B to 70℃, and add the solution C dropwise to the suspension B, and stir for 5 h;

[0218] (4) After sufficient impregnation in step (3), add 0.1 g·mL -1 of potassium hydroxide aqueous solution to the suspension B to adjust the pH of the suspension B to 8, and then stand for 1.5 h; then heat to 70℃, and slowly add 10 mL of an aqueous solution containing 0.77 g of hydrazine hydrate to the suspension B, and reduce for 1 h; cool the suspension B, filter, and wash the filter cake with deionized water until the filtrate is neutral; place the filter cake in a vacuum oven and dry at 110℃ for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS1.

[0219] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method:

[0220] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the kettle was replaced with nitrogen gas three times (each time pressurized to 1 MPa and maintained for 1 min to check the air tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was raised to 140°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature dropped to room temperature, the pressure in the kettle was evacuated, and the reaction liquid was filtered. The filter cake was sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove water, and then the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0221] Comparative Example 3

[0222] 1. Preparation of sulfur-doped activated carbon supported palladium metal catalyst:

[0223] (1) 5 g of completely dried activated carbon (Macklin, 200 mesh, powder) was added to 75 mL of deionized water, stirred thoroughly for 12 h, and then heated to 70°C to evaporate the water, obtaining solid A;

[0224] (2) Solid A was placed in a vacuum oven and dried at 110°C for 12 h; then placed in a tube furnace and calcined at 3°C·min -1 to 600°C under a helium atmosphere, and maintained for 3 h. After cooling to room temperature, sulfur-doped activated carbon support CS0 was obtained;

[0225] (3) 2 g of sulfur-doped activated carbon support was added to 30 mL of deionized water and stirred to disperse at room temperature for 1 h, obtaining suspension B; 0.5077 g of potassium tetrachloropalladate (98%) was added to 20 mL of deionized water, and 0.2 g of polyvinylpyrrolidone (K16-18) was added. After heating to 70°C and stirring for 1 h, solution C was obtained; then suspension B was heated to 70°C, and solution C was added dropwise to suspension B, and stirred for 5 h;

[0226] (4) After sufficient impregnation by step (3), 0.1 g·mL -1Ammonia solution was added to the suspension B, the pH value of the suspension B was adjusted to 10, and then it was left to stand for 1.5 h; then it was heated to 70 °C, 10 mL of an aqueous solution containing 0.58 g of sodium borohydride was slowly added to the suspension B, and it was reduced for 1 h; the suspension B was cooled, suction filtered, and the filter cake was washed repeatedly with deionized water until the filtrate was neutral; the filter cake was placed in a vacuum oven and dried at 110 °C for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS0.

[0227] 2. Use of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolinone by hydrogenation method:

[0228] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and maintained for 1 min to check the air tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was increased to 140 °C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, the reaction liquid was suction filtered, and the filter cake was a sulfur-doped activated carbon supported palladium metal catalyst. After removing the water from the filtrate by distillation, the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0229] Comparative Example 4

[0230] 1. Preparation of a sulfur-doped activated carbon supported palladium metal catalyst:

[0231] (1) 1.1659 g of Na2SO4 was dissolved in 75 mL of deionized water, 5 g of completely dried activated carbon (Macklin, 200 mesh, powder) was added, stirred thoroughly for 12 h, and then heated to 70 °C to evaporate the water, obtaining a solid mixture A;

[0232] (2) The solid mixture A was placed in a vacuum oven and dried at 110 °C for 12 h; then it was placed in a tube furnace and calcined at 3 °C·min -1 to 400 °C under nitrogen atmosphere, and maintained for 3 h, and then cooled to room temperature to obtain a sulfur-doped activated carbon support CS5;

[0233] (3) Add 2g of sulfur-doped activated carbon carrier to 30mL of deionized water and stir to disperse at room temperature for 1h to obtain suspension B; add 0.8965g of palladium nitrate (Pd 18.09wt.%) to 20mL of deionized water, add 0.2g of polyvinylpyrrolidone (K16-18), heat to 70℃ and stir for 1h to obtain solution C; then heat suspension B to 70℃, add solution C dropwise to suspension B, and stir to soak for 5h.

[0234] (4) After thorough soaking in step (3), add 0.1 g·mL -1 Sodium hydroxide aqueous solution was added to suspension B, the pH of suspension B was adjusted to 11, and then it was allowed to stand for 1.5 h; then the temperature was raised to 70 °C, and 10 mL of aqueous solution containing 0.77 g of hydrazine hydrate was slowly added dropwise to suspension B, and reduction was carried out for 1 h; suspension B was cooled and filtered, and the filter cake was repeatedly washed with deionized water until the pH of the filtrate was neutral; the filter cake was placed in a vacuum oven and dried at 110 °C for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 7.5% Pd / CS5.

[0235] 2. Application of catalysts in the hydrogenation synthesis of 1,3-dimethyl-2-imidazolinone:

[0236] Add 12g of 2-imidazolium ketone, 100mL of deionized water, 0.6g of sulfur-doped activated carbon-supported palladium metal catalyst, and 28g of formaldehyde solution (37wt.%) sequentially to a 250mL reactor (Yanzheng Instruments, YZQR-250(M)). Replace the gas inside the reactor three times with nitrogen (pressurizing to 1MPa each time and maintaining the pressure for 1min to check the airtightness). Set the mechanical stirring speed to 1000r·min. -1 When the temperature reaches 140℃, hydrogen gas is introduced until the pressure reaches 1 MPa. When the pressure drops to 0.9 MPa, hydrogen gas is added back to bring the pressure to 1 MPa, and the reaction is stopped when there is no significant pressure change within half an hour. After the reactor temperature drops to room temperature, the pressure inside the reactor is released, and the reaction solution is filtered. The filter cake is a palladium metal catalyst supported on sulfur-doped activated carbon. After the filtrate is distilled to remove moisture, the target product is quantitatively analyzed using a gas chromatograph (Agilent 7890B).

[0237] Comparative Example 5

[0238] 1. Preparation of palladium metal catalyst supported on sulfur-doped activated carbon:

[0239] (1) Dissolve 1.1659g Na2SO4 in 75mL deionized water, add 5g completely dry activated carbon (Maclean, 200 mesh, powder), stir thoroughly for 12h, then heat to 70℃ to evaporate the water, and obtain solid mixture A;

[0240] (2) The solid mixture A was placed in a vacuum oven and dried at 110 °C for 12 h to obtain the uncalcined sulfur-doped activated carbon support CS5 * ;

[0241] (3) 2 g of the uncalcined sulfur-doped activated carbon support was added to 30 mL of deionized water and stirred to disperse at room temperature for 1 h to obtain a suspension B; 0.3818 g of dichlorotetraammine palladium (98%) was added to 20 mL of deionized water, 0.2 g of polyvinylpyrrolidone (K16-18) was added, and the temperature was raised to 70 °C while stirring for 1 h to obtain a solution C; then the suspension B was heated to 70 °C, and the solution C was added dropwise to the suspension B, and the impregnation was stirred for 5 h;

[0242] (4) After sufficient impregnation according to step (3), 0.1 g mL -1 of aqueous potassium hydroxide solution was added to the suspension B to adjust the pH of the suspension B to 9, and then it was allowed to stand for 1.5 h; then the temperature was raised to 70 °C, and 10 mL of an aqueous solution containing 0.58 g of sodium borohydride was slowly added dropwise to the suspension B, and the reduction was carried out for 1 h; the suspension B was cooled and suction filtered, and the filter cake was washed repeatedly with deionized water until the filtrate was neutral; the filter cake was placed in a vacuum oven and dried at 110 °C for 9 h to obtain a sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS5 * .

[0243] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolinone by hydrogenation method:

[0244] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of the sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of a formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and maintained for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r min -1 When the temperature was raised to 140 °C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa, and the reaction was stopped until the pressure did not change significantly within half an hour. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, the reaction liquid was suction filtered, and the filter cake was the sulfur-doped activated carbon supported palladium metal catalyst. After removing the water from the filtrate by distillation, the target product was quantitatively analyzed by a gas chromatograph (Agilent 7890B).

[0245] Comparative Example 6

[0246] 1. Preparation of a sulfur-doped activated carbon supported palladium metal catalyst:

[0247] (1) Dissolve 1.1659 g Na2SO4 in 75 mL deionized water, add 5 g completely dried activated carbon (Mcclin, 200 mesh, powder), stir well for 12 h, then heat to 70 °C to evaporate water, and obtain solid mixture A;

[0248] (2) Dry solid mixture A in a vacuum oven at 110 °C for 12 h, then calcine in a tube furnace under argon atmosphere at a rate of 3 °C·min -1 to 600 °C for 3 h, and keep the temperature for 3 h. After cooling to room temperature, sulfur-doped activated carbon support CS5 is obtained;

[0249] (3) Add 2 g sulfur-doped activated carbon support into 30 mL deionized water, and stir to disperse at room temperature for 1 h to obtain suspension B. Separately, add 8.1 mL aqueous solution of tetrachloropalladium acid (Pd 0.02 g·mL -1 ) into 20 mL deionized water, heat to 70 °C, and keep stirring for 1 h to obtain solution C. Then heat suspension B to 70 °C, and add solution C dropwise into suspension B, and stir for 5 h;

[0250] (4) After sufficient impregnation in step (3), add 0.1 g·mL -1 aqueous ammonia solution into suspension B, adjust the pH value of suspension B to 8, and then stand for 1.5 h. Then heat to 70 °C, and slowly drop 10 mL aqueous solution containing 0.77 g hydrazine hydrate into suspension B, and reduce for 1 h. Cool suspension B, and perform suction filtration, and repeatedly wash the filter cake with deionized water until the pH value of the filtrate is neutral. Dry the filter cake in a vacuum oven at 110 °C for 9 h, and obtain sulfur-doped activated carbon supported palladium metal catalyst 7.5%Pd / CS5.

[0251] 2. Application of the catalyst in the synthesis of 1,3-dimethyl-2-imidazolinone by hydrogenation method:

[0252] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), sequentially add 12 g 2-imidazolidinone, 100 mL deionized water, 0.6 g sulfur-doped activated carbon supported palladium metal catalyst, and 28 g formaldehyde solution (37 wt.%), and replace the gas in the kettle with nitrogen three times (each time pressurize to 1 MPa and keep for 1 min to check the air tightness of the device). Set the mechanical stirring rate to 1000 r·min -1When the temperature was raised to 140°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa until there was no significant change in pressure within half an hour, and the reaction was stopped. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered. The filter cake was a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove moisture, and then the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0253] Comparative Example 7

[0254] Comparative Example 7 investigated the application of the catalyst prepared in Example 1 in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method at different reaction temperatures.

[0255] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and maintained for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was raised to 120°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa until there was no significant change in pressure within half an hour, and the reaction was stopped. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered. The filter cake was a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove moisture, and then the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0256] Comparative Example 8

[0257] Comparative Example 8 investigated the application of the catalyst prepared in Example 1 in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method at different reaction temperatures.

[0258] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and maintained for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1When the temperature was raised to 130°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa until there was no significant change in pressure within half an hour, and the reaction was stopped. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered. The filter cake was a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove moisture, and then the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0259] Comparative Example 9

[0260] Comparative Example 9 investigated the application of the catalyst prepared in Example 1 in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method under different reaction pressures.

[0261] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of sulfur-doped activated carbon supported palladium metal catalyst, and 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and maintained for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1 When the temperature was raised to 140°C, hydrogen was introduced to a pressure of 0.5 MPa. When the pressure dropped to 0.4 MPa, hydrogen was added to 1 MPa until there was no significant change in pressure within half an hour, and the reaction was stopped. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered. The filter cake was a sulfur-doped activated carbon supported palladium metal catalyst, and the filtrate was treated by distillation to remove moisture, and then the target product was quantitatively analyzed by gas chromatograph (Agilent 7890B).

[0262] Comparative Example 10

[0263] Comparative Example 10 investigated the application of commercial 5% Pd / C catalyst in the synthesis of 1,3-dimethyl-2-imidazolidinone by hydrogenation method.

[0264] Into a 250 mL reaction kettle (Yanzheng instrument, YZQR-250(M)), 12 g of 2-imidazolidinone, 100 mL of deionized water, 0.6 g of commercial 5% Pd / C catalyst (Huzhou Degong Chemical Co., Ltd.), and 28 g of formaldehyde solution (37 wt.%) were sequentially added, and the gas in the kettle was replaced with nitrogen three times (each time the pressure was increased to 1 MPa and maintained for 1 min to check the gas tightness of the device). The mechanical stirring rate was set to 1000 r·min -1When the temperature was raised to 140°C, hydrogen was introduced to a pressure of 1 MPa. When the pressure dropped to 0.9 MPa, hydrogen was added to 1 MPa until the pressure did not change significantly within half an hour, and the reaction was stopped. When the kettle temperature dropped to room temperature, the pressure in the kettle was emptied, and the reaction liquid was filtered, the filter cake was a commercial palladium-carbon catalyst, and the filtrate was treated by distillation to remove moisture, and then the target product was quantitatively analyzed by gas chromatography (Agilent 7890B).

[0265] Table 8 Catalytic performance of the catalyst prepared in Example 3 and a commercial 5% Pd / C catalyst

[0266]

[0267]

Claims

1. Use of a sulfur-doped activated carbon supported palladium metal catalyst in the synthesis of 1,3-dimethyl-2-imidazolinone by hydrogenative methods, characterized in that: The application comprises the following steps: sequentially adding 2-imidazolidinone, deionized water, sulfur-doped activated carbon supported palladium metal catalyst and formaldehyde solution into a reaction kettle, and performing continuous hydrogenation reaction under the conditions of 130-160 DEG C, hydrogen pressure of 1-5 MPa and mechanical stirring to synthesize 1,3-dimethyl-2-imidazolidinone; the preparation method of the sulfur-doped activated carbon supported palladium metal catalyst comprises the following steps: (1) dissolving a sulfur atom precursor in deionized water, adding completely dried activated carbon, stirring thoroughly for 6-12 hours, then heating to 60-80 ℃ to evaporate water, obtaining a solid mixture A; the sulfur atom precursor is at least one selected from Na2SO4, Na2S, NaHSO3, Na2SO3, Na2S2O3, K2SO4, K2S, KHSO3, K2SO3, K2S2O3, H2SO4, methyl sulfonic acid, benzene sulfonic acid, p-toluene sulfonic acid, α-naphthalene sulfonic acid, β-naphthalene sulfonic acid, 2-mercaptoethanol, dimethyl sulfone, phenyl vinyl sulfone, sodium dodecyl sulfate; the sulfur atom precursor and activated carbon are according to the theoretical doping amount of sulfur atom y%=m S / (m S +m 活性炭 )×100%=2-10% of the feed, wherein m S is the mass of S element contained in the added sulfur atom precursor; (2) drying the solid mixture A in a vacuum oven, and then calcining the mixture in a tube furnace under an inert atmosphere at 500-800 DEG C for 3-5 h, and obtaining a sulfur-doped activated carbon carrier after cooling to room temperature; (3) adding the sulfur-doped activated carbon carrier into a proper amount of deionized water, stirring and dispersing uniformly at room temperature to obtain a suspension B; and adding a palladium metal precursor compound into a proper amount of deionized water, heating and warming to 60-80 DEG C, and keeping stirring for 1-3 h to obtain a solution C; Subsequently, the suspension B is heated to 60-80 ℃, and the solution C is added dropwise into the suspension B, and immersed for 3-5 h; the suspension B and the solution C are according to the theoretical loading amount x% of Pd Pd / (m Pd +m 硫掺杂活性炭载体 )×100%=3-10% of the feed, wherein m Pd is the mass of Pd element contained in the solution C, and m 硫掺杂活性炭载体 is the mass of the sulfur-doped activated carbon carrier contained in the suspension B; (4) after sufficient immersion according to step (3), adding a proper amount of lye into the suspension B to adjust the pH value of the suspension B to 8-11, and then standing for 1.5-2 h; subsequently, heating and warming to 60-80 DEG C, slowly dropping a proper amount of aqueous solution containing a liquid phase reducing agent into the suspension B for sufficient reduction; cooling and suction filtering the suspension B, and repeatedly washing the filter cake with deionized water until the pH value of the filtrate is neutral; and drying the filter cake to obtain the sulfur-doped activated carbon supported palladium metal catalyst.

2. Use according to claim 1, characterized in that: In step (2), y is 2-7.

3. Use according to claim 2, wherein: In step (2), y is 5.

4. The use according to claim 1, characterized in that: In step (2), the rate of temperature increase to the calcination temperature is 1-5°C·min -1 , the calcination temperature is 500-800°C, and the calcination time is 3-5 h.

5. The use according to claim 4, wherein: In step (2), the temperature increasing rate is 3 °C·min -1 , the calcination temperature is 600 °C, and the calcination time is 3 h.

6. The use according to claim 1, characterized in that: In step (3), the sulfur-doped activated carbon carrier is added into a proper amount of deionized water, and stirring and dispersing is performed for 1-3 h at room temperature.

7. The use according to claim 1, characterized in that: In step (3), the palladium metal precursor compound is at least one of tetrachloropalladic acid, sodium tetrachloropalladic acid, potassium tetrachloropalladic acid, palladium nitrate and dichlorotetraammine palladium.

8. The use according to claim 1, characterized in that: In step (3), in addition to the palladium metal precursor compound and deionized water, a dispersant is also added when the solution C is prepared, the dispersant is at least one of polyvinylpyrrolidone and polyethylene glycol, and the mass amount of the dispersant is 5-10% of the mass amount of the sulfur-doped activated carbon carrier.

9. The use according to claim 1, characterized in that: In step (3), x is 5-10.

10. Use according to claim 9, wherein: In step (3), x is 7.

5.

11. Use according to claim 1, characterized in that: In step (4), the liquid phase reducing agent is at least one of sodium borohydride and hydrazine hydrate, and the molar ratio of the liquid phase reducing agent to palladium element is 5-15:1; and the reduction time is 1-2 h.

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