Sulfo-imidazolidinone compound based on microwave-assisted method and preparation method and application thereof

Abstract

The invention discloses a thioimidazolidinone compound based on a microwave-assisted method as well as a preparation method and application of the thioimidazolidinone compound, and belongs to the technical field of compound preparation. The invention solves the problems of toxic solvent use, low yield, long time, more byproducts and the like in the traditional synthesis method of the thioimidazolidinone compound. According to the method, alpha-amino acid is taken as a raw material, water is taken as a solvent, the reaction time is shortened from several hours to minute level by utilizing the microwave field induced heat effect, the thioimidazolidinone compound is successfully synthesized, and the reaction rate and the yield are improved by adopting the phase transfer catalyst. The use of toxic solvents such as DMF (Dimethyl Formamide) is avoided, the reaction time is shortened, and the product yield exceeds 95%. Besides, the thioimidazolidinone compound can be independently used as a corrosion inhibitor and can also be compounded with a surfactant and / or a synergistic agent for use, and the corrosion inhibition effect is excellent; the thioimidazolidinone compound can also be used in the fields of medicines, pesticides, material synthesis and fine chemical engineering, and has wide application scenarios.

Description

Technical Field

[0001] The present invention belongs to the technical field of compound preparation, and particularly relates to a thioimidazolidinone compound based on a microwave-assisted method, a preparation method thereof, and an application thereof. Background Art

[0002] Thioimidazolidinone compounds have unique chemical properties and biological activities, and have important applications in the fields of pharmaceutical synthesis, pesticide preparation, material synthesis, and fine chemicals. At the same time, these compounds exhibit good corrosion inhibition properties and can be used for the anti-corrosion of industrial metals. Therefore, the synthesis of thioimidazolidinone compounds is becoming increasingly important.

[0003] However, the existing synthesis methods of thioimidazolidinone compounds mostly rely on traditional thermodynamic reaction systems, usually using high-boiling organic solvents (such as DMF, DMSO, etc.) as media. The reaction time is as long as several hours to dozens of hours, and there are many by-products generated during the reaction, resulting in complex product separation and purification steps and low yields. In addition, the existing processes mostly involve toxic reagents or high-temperature and high-pressure conditions, with defects such as high energy consumption, poor operation safety, and insufficient environmental friendliness. In addition, due to various defects in the current preparation methods, such as many by-products and low yields of the prepared compounds, the application effects and fields of this compound are limited. Therefore, there is an urgent need to develop a synthesis method of thioimidazolidinone compounds with mild reaction conditions, simple steps, high yields, no use of toxic and harmful raw materials, and environmental friendliness, so as to give full play to the potential application value of this type of compound, which is of great significance for improving the preparation efficiency, application effects of this type of compound, and expanding its application scope. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a thioimidazolidinone compound based on a microwave-assisted method, a preparation method thereof, and an application thereof.

[0005] Technical Solution of the Present Invention:

[0006] One of the purposes of the present invention is to provide a preparation method of a thioimidazolidinone compound based on a microwave-assisted method. The method is as follows: Dissolve α-amino acid and a phase transfer catalyst in a solvent, stir to form a uniform solution, add a basic catalyst to the uniform solution, continue stirring, add an isothiocyanate compound after the stirring ends, and then carry out a microwave-assisted reaction. After the reaction ends, cool to room temperature, and successively carry out acidification, washing, filtration, and recrystallization processes on the product to obtain a thioimidazolidinone compound.

[0007] Further limited, the phase transfer catalyst is a quaternary ammonium salt type phase transfer catalyst or a non-ionic phase transfer catalyst.

[0008] Further limited, the solvent is water.

[0009] Further limitation: the basic catalyst is an organic weak base, and the isothiocyanate compound is an alkyl isothiocyanate or an aryl isothiocyanate.

[0010] Even further limitation: the organic weak base is an amine compound having a deprotonation effect.

[0011] Further limitation: the molar ratio of the α-amino acid to the isothiocyanate compound is 1:(0.83 - 1.20).

[0012] Further limitation: the dosage of the basic catalyst is (0.5 - 1.2) times the equivalent amount of the sum of the α-amino acid and the isothiocyanate compound.

[0013] Further limitation: the molar volume ratio of the sum of the α-amino acid and the isothiocyanate compound to the solvent is 1 mol:(2500 - 3000) mL.

[0014] Further limitation: the dosage of the phase transfer catalyst is 5 - 20% of the total mass of the α-amino acid, the isothiocyanate compound and the basic catalyst.

[0015] Further limitation: the process parameters of the microwave-assisted reaction are: the power is not greater than 1000 W, the temperature is 40 - 80 °C, and the reaction time is 3 - 15 min.

[0016] The second object of the present invention is to provide a thioimidazolidinone compound prepared by using the above method.

[0017] The third object of the present invention is to provide an application of the above thioimidazolidinone compound. Specifically, the thioimidazolidinone compound is used alone as a corrosion inhibitor or as a corrosion inhibition component to prepare a compound corrosion inhibitor.

[0018] The fourth object of the present invention is to provide an application of the above thioimidazolidinone compound. Specifically, the thioimidazolidinone compound is used in the fields of pharmaceutical synthesis, pesticide preparation and fine chemical industry.

[0019] The fifth object of the present invention is to provide a compound corrosion inhibitor, and the chemical components include, by weight percentage: 50 - 90% of the thioimidazolidinone compound obtained by the above preparation method, 10 - 40% of a surfactant, and 0 - 10% of a synergistic agent.

[0020] Further limitation: the surfactant is a nonionic surfactant or an anionic surfactant.

[0021] Even further limitation: the synergistic agent is a thio small molecule derivative.

[0022] The beneficial effects of the present invention:

[0023] (1) The present invention uses α - amino acids as raw materials, water as a solvent, and synthesizes thioimidazolidinone compounds by microwave - assisted method. In the synthesis process, a phase - transfer catalyst is used to improve the reaction rate and yield.

[0024] (2) The method provided by the present invention successfully synthesizes thioimidazolidinone compounds under the condition that the solvent is water, avoiding the use of toxic solvents such as DMF. And by using the thermal effect induced by the microwave field, the reaction time is shortened from several hours in the conventional method to the minute level, greatly reducing the reaction time. In addition, the product synthesized by the present invention has a high purity, almost no by - products, and the yield exceeds 95%. It is a green, simple and efficient synthesis method.

[0025] (3) The thioimidazolidinone compounds synthesized by the present invention have extended their applications in multiple fields due to their high yield, high purity and short synthesis time. This compound can be used for the development of antibacterial, anti - inflammatory and anti - tumor drugs in the pharmaceutical field; it can be used as a plant protection agent or fungicide in the pesticide field; in the fine chemical industry, it plays an important role in synthetic processes such as organic catalysis and dye synthesis. In addition, the thioimidazolidinone compounds of the present invention can be used alone as corrosion inhibitors or can be compounded with surfactants and / or synergists.

[0026] (4) The structure of the thioimidazolidinone compounds synthesized by the present invention contains multiple electron - rich functional groups at the same time, such as sulfur atoms (S), nitrogen atoms (N) and carbonyl oxygen atoms (O). The thiocarbonyl group (C = S) in the structure and the sulfur - or nitrogen - containing substituents in the amino acid side chain can act as electron donors for metal - affinity, forming a stable coordination adsorption layer on the metal surface; the two nitrogen atoms in the imidazolidinone ring structure also have strong coordination ability, which helps to enhance the binding strength between the thioimidazolidinone compound and the metal surface. In addition, the thioimidazolidinone compounds synthesized by the present invention retain some hydrophilic groups (-OH, -COOH, -NH2) or hydrophobic groups (alkyl, aryl) in the amino acid molecular structure, making the compound have both polar interactions to enhance adsorption during the adsorption process and form a certain hydrophobic barrier, effectively isolating the erosion of water and corrosive ions on the metal surface. When the isothiocyanate compound used in the present invention is aryl isothiocyanate, the synthesized thioimidazolidinone compound has an aromatic substituent, and this type of aromatic ring structure can enhance the compactness and stability of the adsorption film formed by the thioimidazolidinone compound on the metal surface through π - π interactions. Generally speaking, the thioimidazolidinone compounds of the present invention form a dense, stable and hydrophobic organic protective film on the metal surface through the synergistic mechanism of chemical adsorption and physical adsorption, thus significantly inhibiting the occurrence of corrosion reactions.

[0027] (5) When the thioimidazolidinone compound of the present invention is used in combination with a surfactant, the surfactant can significantly reduce the surface tension of the metal, enhance the diffusion rate and adsorption uniformity of the compound inhibitor on the metal surface, and thus accelerate the formation of a dense inhibitor film layer. The hydrophobic chain segment of the surfactant can further arrange on the outside of the adsorption layer, enhancing the hydrophobicity and stability of the entire film layer. On the other hand, when the compound inhibitor of the present invention contains a synergistic agent, the synergistic agent contains multiple sulfur atoms and amino groups, with concentrated electron cloud density, which can form a firm coordination adsorption with the metal surface and form a composite adsorption structure with the thioimidazolidinone compound through hydrogen bonding, electrostatic interaction or intermolecular interaction, thereby enhancing the compactness, coverage rate and mechanical stability of the film layer, and further improving the corrosion inhibition efficiency of the inhibitor. Description of the Drawings

[0028] Figure 1 are the impedance curves of N80 carbon steel when no inhibitor is used and when the inhibitors prepared in Examples 3 - 8 are used;

[0029] Figure 2 is the NMR spectrum ([ 1 H NMR) of MTEPI synthesized in Example 1;

[0030] Figure 3 is the infrared spectrum of MTEPI synthesized in Example 1. Detailed Embodiments

[0031] To make the above objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is made in conjunction with the embodiments of the specification.

[0032] Many specific details are set forth in the following description in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0033] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that can be included in at least one implementation manner of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selectively exclusive embodiment from other embodiments.

[0034] The experimental methods used in the following embodiments are all conventional methods unless otherwise specified. The materials, reagents, methods and instruments used, unless otherwise specified, are all conventional materials, reagents, methods and instruments in the art, and those skilled in the art can obtain them through commercial channels.

[0035] The model of the microwave reactor used in the following examples is the high-pressure ultrasonic microwave synergistic combination workstation XH-300PE.

[0036] Example 1

[0037] In this example, the thioimidazolidinone compound 5-(2-(methylthio)ethyl)-3-phenyl-2-thioimidazolidin-4-one (MTEPI) was synthesized, and its synthetic route is as follows:

[0038]

[0039] (1) Dissolve 1.5 g of L-methionine and 0.73 g of the phase transfer catalyst cetyltrimethylammonium bromide (CTAB) in water, stir to form a homogeneous solution, add 2 g of the basic catalyst triethylamine to the homogeneous solution, continue stirring for 5 minutes, then slowly add 1.36 g of phenyl isothiocyanate, stir, and place the reaction system in a microwave reactor. Set the power to 1000 W, the temperature to 60 °C, and the reaction time to 5 minutes;

[0040] (2) After the reaction is completed, cool the system to room temperature, add 15 - 20 mL of 1 mol / L hydrochloric acid for acidification treatment until precipitation occurs in the system. At this time, pH = 6. Filter the precipitate to obtain the crude product, and wash it with deionized water;

[0041] (3) Collect the washed crude product, dissolve it in hot ethanol and stir until the crude product is completely dissolved. Cool the solution to room temperature, then refrigerate it. After white needle-shaped or slightly yellow needle-shaped crystals are formed, filter the solution to obtain the first recrystallized product. Recrystallize a total of 2 times to obtain MTEPI, and the yield is greater than 95%.

[0042] The nuclear magnetic resonance of MTEPI synthesized in this example 1 H NMR is as Figure 2 shown: 1 H NMR (400 MHz, Chloroform-d) δ 8.51 (brs, 1H), 7.50 (m, 3H), 7.36 - 7.30 (m, 2H), 4.43 (m, 1H), 2.69 (t, J = 6.8 Hz, 2H), 2.31 (m, 1H), 2.20 - 2.13 (m, 1H), 2.10 (s, 3H).

[0043] The infrared spectrum of MTEPI synthesized in this example is as Figure 3 shown. A medium-intensity absorption peak appears at 3169.84 cm -1 , corresponding to the N–H stretching vibration in the imidazolidinone structure, indicating that the compound molecule contains an amine group; 2985.77 cm -1 and 2911.86 cm -1The peak at [specific position] corresponds to the C-H stretching vibrations in -CH3 and -CH2- in the methionine ethyl side chain; at 1748.77 cm -1 A strong absorption peak was observed at [specific position], corresponding to the carbonyl (C=O) stretching vibration, indicating the presence of the imidazolidin-4-one structure; 1524.7 cm -1 and 1595.39 cm -1 The absorption peaks are characteristic peaks of aromatic ring C=C stretching vibrations, indicating the presence of a phenyl structure in the compound molecule; 1410.21 cm -1 、1355.52 cm -1 and 1340.33 cm -1 The absorption peaks such as are attributed to the stretching vibrations of C-N bonds in the heterocyclic structure, usually appearing in the range of 1300 - 1500 cm -1 ; In addition, the absorption peak at 1206.74 cm -1 corresponds to the stretching vibration of the C=S bond. In the low wavenumber region, such as 786.20 cm -1 、744.79 cm -1 、708.71 cm -1 and 692.59 cm -1 The absorption peaks represent the out-of-plane bending vibrations of C–H on the aromatic ring. The results of the infrared spectrum show that the positions of the infrared absorption peaks in this compound are highly consistent with the structure of 5-(2-(methylthio)ethyl)-3-phenyl-2-thioimidazolidin-4-one, indicating the successful synthesis of MTEPI.

[0044] Comparative Example 1

[0045] (1) Dissolve 1.5 g of L-methionine and 2 g of triethylamine in 50 mL of a solvent composed of N,N-dimethylformamide (DMF) and water (DMF: water = 8:2, v / v), then add 1.36 g of phenyl isothiocyanate to the solution, stir the reaction system at room temperature for 6 h, and monitor the reaction progress by thin layer chromatography (TLC, ethyl acetate / hexane = 30% or methanol / chloroform = 5 - 10%) until the reaction is complete;

[0046] (2) After the reaction is completed, cool the system to room temperature, add 200 - 250 mL of 1 mol / L hydrochloric acid for acidification treatment until precipitation occurs in the system, at which time pH = 1, filter the precipitate to obtain the crude product, and wash it with deionized water;

[0047] (3) The operation process and parameter settings in this step are the same as those in (3) of Example 1 to obtain MTEPI with a yield of 70%.

[0048] Example 2

[0049] In this embodiment, the thioimidazolidinone compound (5-(mercaptomethyl)-3-phenyl-2-thioimidazolidin-4-one) is synthesized, and its synthetic route is as follows:

[0050]

[0051] The difference between this embodiment and Embodiment 1 is that the synthesized thioimidazolidinone compound is (5-(mercaptomethyl)-3-phenyl-2-thioimidazolidin-4-one). The amino acid used in (1) is L-cysteine, with a dosage of 1.2 g, and the dosage of the phase transfer catalyst cetyltrimethylammonium bromide (CTAB) is 0.68 g. The remaining process steps and parameter settings are the same as those in Embodiment 1.

[0052] The yield of this embodiment is greater than 95%.

[0053] Comparative Example 2

[0054] (1) Dissolve 1.2 g of L-cysteine and 2 g of triethylamine in 50 mL of a solvent composed of N,N-dimethylformamide (DMF) and water (DMF: water = 8:2, v / v), then add 1.36 g of phenyl isothiocyanate to the solution, and stir the reaction system at room temperature for 10 h. Monitor the reaction progress by thin layer chromatography (TLC, ethyl acetate / hexane = 30% or methanol / chloroform = 5 - 10%) until the reaction is complete;

[0055] (2) After the reaction is completed, cool the system to room temperature, add 200 - 250 mL of 1 mol / L hydrochloric acid for acidification until precipitation occurs in the system, at which time pH = 1. Filter the precipitate to obtain the crude product, and wash it with deionized water;

[0056] (3) The operation process and parameter settings in this step are the same as those in (3) of Embodiment 1, and (5-(mercaptomethyl)-3-phenyl-2-thioimidazolidin-4-one) is obtained, with a yield of 75%.

[0057] In Comparative Example 1 and Comparative Example 2, the solvents used are both solutions composed of DMF and water, and DMF is used in both. The long-term use of this substance has potential hazards to the human body and the environment, making the traditional synthesis method not environmentally friendly; moreover, the reaction time in Comparative Example 1 is as long as 6 h, and the reaction time in Comparative Example 2 is as long as 10 h, which is several times that of Embodiment 1. The long reaction time increases the energy consumption for the preparation of thioimidazolidinone compounds; and when acidifying with hydrochloric acid, a large amount of hydrochloric acid is used in Comparative Example 1 - 2 to precipitate the precipitate, which not only increases the preparation cost but also increases the potential pollution and safety risks, while only a small amount of hydrochloric acid is required in Embodiment 1 - 2 to precipitate the precipitate. In addition, the yields of Comparative Example 1 - 2 are relatively low. After recrystallizing twice with absolute ethanol, the yields are 70% and 75% respectively.

[0058] Embodiment 3

[0059] Using the MTEPI obtained in Example 1 as a corrosion inhibitor, the corrosion performance of this corrosion inhibitor was tested in a carbon dioxide corrosion system.

[0060] Example 4

[0061] Using the MTEPI obtained in Example 1 as one of the components, it was compounded with the non-ionic surfactant fatty alcohol polyoxyethylene ether (AEO) to obtain a compound corrosion inhibitor. The chemical composition of this corrosion inhibitor includes by weight percentage: 70% of MTEPI obtained in Example 1 and 30% of AEO. The corrosion performance of this compound corrosion inhibitor was tested in a carbon dioxide corrosion system.

[0062] Example 5

[0063] Using the MTEPI obtained in Example 1 as one of the components, it was compounded with the anionic surfactant sodium dodecylbenzenesulfonate (SDBS) to obtain a compound corrosion inhibitor. The chemical composition of this corrosion inhibitor includes by weight percentage: 70% of MTEPI obtained in Example 1 and 30% of SDBS. The corrosion performance of this compound corrosion inhibitor was tested in a carbon dioxide corrosion system.

[0064] Example 6

[0065] Using the MTEPI obtained in Example 1 as one of the components, it was compounded with the non-ionic surfactant fatty alcohol polyoxyethylene ether (AEO) and the synergistic agent thiourea (TU) to obtain a compound corrosion inhibitor. The chemical composition of this corrosion inhibitor includes by weight percentage: 72% of MTEPI obtained in Example 1, 18% of AEO, and 10% of TU. The corrosion performance of this compound corrosion inhibitor was tested in a carbon dioxide corrosion system.

[0066] Example 7

[0067] Using the MTEPI obtained in Example 1 as one of the components, it was compounded with the non-ionic surfactant fatty alcohol polyoxyethylene ether (AEO) and the synergistic agent 2-mercaptobenzimidazole (MBI) to obtain a compound corrosion inhibitor. The chemical composition of this corrosion inhibitor includes by weight percentage: 72% of MTEPI obtained in Example 1, 18% of AEO, and 10% of MBI. The corrosion performance of this compound corrosion inhibitor was tested in a carbon dioxide corrosion system.

[0068] Example 8

[0069] Taking the MTEPI obtained in Example 1 as one of the components, it is compounded with the non-ionic surfactant fatty alcohol polyoxyethylene ether (AEO), the synergist 2-mercaptobenzimidazole (MBI) and thiourea (TU) to obtain a compound corrosion inhibitor. The chemical composition of this corrosion inhibitor includes, by weight percentage: 72% of MTEPI obtained in Example 1, 18% of AEO, 5% of MBI, and 5% of TU. The corrosion performance of this compound corrosion inhibitor is tested in a carbon dioxide corrosion system.

[0070] The corrosion performance of the corrosion inhibitors in Examples 3 to 8 is tested in a carbon dioxide corrosion system:

[0071] Taking N80 carbon steel as the test material, it is polished successively with 400, 800, 1000 and 1500 grit silicon carbide sandpapers, rinsed successively with acetone and absolute ethanol, and then dried with hot air for standby;

[0072] During the test, a brine solution simulating the oilfield environment was used. The formula of the brine solution was 2.587 g / L of NaCl, 1.740 g / L of NaHCO3, 0.323 g / L of CaCl2, and 0.070 g / L of MgCl2. A total of 11 brine solutions were prepared (each brine solution had a volume of 1 L). The first one was a blank control group without adding corrosion inhibitor. High-purity N2 was introduced into the 11 brine solutions for 2 h to ensure complete removal of O2, and then CO2 was introduced into the 11 brine solutions for 2 h to obtain a saturated carbon dioxide salt solution. The corrosion inhibitors and compound corrosion inhibitors of Examples 3 - 8 were respectively dissolved in absolute ethanol to form ethanol solutions. The amount of absolute ethanol used was less, and the purpose was to dissolve the corrosion inhibitor, which could be ignored. Ethanol solutions prepared by dissolving MTEPI of Example 3 were added to the 2nd - 6th saturated carbon dioxide salt solutions respectively, and the MTEPI concentrations were 10 ppm, 20 ppm, 50 ppm, 100 ppm, and 200 ppm respectively (the MTEPI concentrations mentioned here are the addition amounts of MTEPI required in the saturated carbon dioxide salt solution. For example, 100 ppm means that the total amount of MTEPI required in 1 L of saturated carbon dioxide salt solution is 0.1 g); Ethanol solutions prepared by adding the compound corrosion inhibitors of Examples 4 - 8 were added to the 7th - 11th saturated carbon dioxide salt solutions respectively, and the concentrations of the compound corrosion inhibitors were all 100 ppm (the concentrations of the compound corrosion inhibitors mentioned here are the addition amounts of the compound corrosion inhibitors required in the saturated carbon dioxide salt solution. For example, 100 ppm means that the total amount of the compound corrosion inhibitor required in 1 L of saturated carbon dioxide salt solution is 0.1 g), and test solutions 1 - 11 were obtained respectively. Then, electrochemical impedance tests were carried out on test solutions 1 - 11 respectively. During the process of adding the corrosion inhibitor and the electrochemical impedance test, CO2 was continuously introduced to keep the salt solution in a saturated state. Electrochemical impedance test method: The experimental temperature was 60 °C. The electrochemical impedance test used a Gamry 600+ workstation, and a three-electrode test system was adopted. The working electrode was N80 carbon steel, the reference electrode was a saturated calomel electrode (SCE), and the platinum electrode was the auxiliary electrode. Among them, the exposed area of N80 carbon steel was 1 cm 2 . The test frequency was from 0.01 Hz to 100 kHz, and the amplitude of the alternating voltage signal was 10 mV. The impedance data was analyzed and fitted through Zsimpwin software. The corrosion inhibition efficiency η z was calculated by Equation (1):

[0073]

[0074] where, R p(inh) and R p(0) respectively represent the total resistance with and without the corrosion inhibitor, R f represents the resistance of the corrosion inhibitor film formed on the surface of N80 carbon steel by the corrosion inhibitor, and R ct represents the charge transfer resistance, Rp = R f + R ct is the total resistance. The results of the electrochemical impedance test are shown in Table 1.

[0075] Table 1 EIS test results of N80 carbon steel in saturated carbon dioxide salt solution without and with corrosion inhibitors of Examples 3 - 8

[0076]

[0077] As can be seen from the data in Table 1, after adding the corrosion inhibitor, the corrosion inhibition efficiency η z significantly increases, and the corrosion inhibition effect on N80 carbon steel is significantly enhanced. This shows that in the carbon dioxide corrosion system, the MTEPI of Example 1 alone as a corrosion inhibitor or the compound corrosion inhibitor obtained with other substances all show good corrosion resistance to N80 carbon steel within the range of 10 - 200 ppm. When the MTEPI of Example 1 is used alone as a corrosion inhibitor, its corrosion inhibition efficiency shows a significant increasing trend with the increase of the use concentration. At the same use concentration (100 ppm), when the MTEPI of Example 1 is compounded with a surfactant, and when the MTEPI is compounded with a surfactant and a synergist, the corrosion inhibition efficiency can also be improved, and the electrochemical impedance experiment proves that the corrosion inhibition performance of the compound corrosion inhibitor is better than that of the single MTEPI corrosion inhibitor.

[0078] As described above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a thioimidazolidinone compound based on a microwave-assisted method, characterized in that: The method comprises the following steps: dissolving an α-amino acid and a phase transfer catalyst in a solvent, stirring to form a uniform solution, adding a basic catalyst to the uniform solution, continuing stirring, adding an isothiocyanate compound after the stirring is completed, then performing a microwave-assisted reaction, cooling to room temperature after the reaction is completed, and sequentially performing acidification, washing, filtering and recrystallization steps on the product to obtain a thioimidazolidinone compound.

2. The preparation method according to claim 1, characterized in that The phase transfer catalyst is a quaternary ammonium salt phase transfer catalyst or a non-ionic phase transfer catalyst; the solvent is water; the alkaline catalyst is an organic weak base; and the isothiocyanate compound is an alkyl isothiocyanate or an aryl isothiocyanate.

3. The preparation method according to claim 1, characterized in that The molar ratio of the α-amino acid to the isothiocyanate compound is 1:(0.83-1.20); the amount of the alkaline catalyst is (0.5-1.2) times the equivalent of the sum of the α-amino acid and the isothiocyanate compound; the amount of the phase transfer catalyst is 5-20% of the total mass of the α-amino acid, the isothiocyanate compound and the alkaline catalyst; and the molar volume ratio of the sum of the α-amino acid and the isothiocyanate compound to the solvent is 1 mol:(2500-3000) mL.

4. The preparation method according to claim 1, characterized in that It is further defined that the process parameters of the microwave-assisted reaction are: power not greater than 1000 W, temperature 40-80° C., and reaction time 3-15 min.

5. A thioimidazolidinone compound based on a microwave-assisted method, characterized in that: The method is prepared by any one of claims 1 to 4.

6. Use of the thioimidazolidinone compound according to claim 5, characterized in that: The thioimidazole ketone compound is used alone as a corrosion inhibitor or as a corrosion inhibitor component to prepare a composite corrosion inhibitor.

7. Use of the thioimidazolidinone compound according to claim 5, characterized in that: The thioimidazole ketone compound is used in pharmaceutical synthesis, pesticide preparation and fine chemical fields.

8. A composite corrosion inhibitor, characterized in that: Calculated by weight percentage, the compound corrosion inhibitor comprises: 50-90% of the thioimidazolidinone compound obtained by the preparation method according to claim 1, 10-40% of a surfactant, and 0-10% of a synergist.

9. The composite corrosion inhibitor according to claim 8, characterized in that The surfactant is a nonionic surfactant or an anionic surfactant.

10. The composite corrosion inhibitor according to claim 9, characterized in that: The synergistic enhancer is a thio small molecule derivative.

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