An aggregation-induced luminescence dust suppressant based on thiazolothiazole-bridged imidazole

Abstract

The present invention relates to an aggregation-induced luminescence dust suppressant based on thiazolothiazole-bridged imidazole, belonging to the technical field of dust suppressants. The compound is represented by the following formula I: wherein R is selected from H, CH3 or CH3(CH2) n , n is 1 to 17; X is selected from Cl, Br, I, F, CH3COO, CF3COO, CF3SO2, (CF3SO2)N, SbF6, BF4, B(C6F6)4, or C4F9. The present invention uses an aggregation-induced luminescence dust suppressant based on thiazolothiazole-bridged imidazole as a dust suppressant for railway coal transportation and sprays it on the coal surface. The luminescent material in the dust suppressant can emit fluorescence under ultraviolet light, achieving long-distance visibility to the naked eye. It also exhibits good water solubility and biocompatibility, a high boiling point, high luminescence intensity, no metal ions, low toxicity, simple synthesis, and low price. It can be well applied in railway coal transportation and achieve remote detection.

Description

Technical Field

[0001] The invention relates to the technical field of dust suppressants, and in particular to an aggregation-induced luminescence dust suppressant based on thiazolothiazole-bridged imidazole. Background Art

[0002] Coal resources continue to play a crucial role in my country's energy mix. However, given the country's increasingly stringent environmental pollution control regulations, achieving clean production in the coal industry has become increasingly crucial. Throughout the coal lifecycle, including mining, crushing, screening, transportation, storage, and coal rock crushing, significant amounts of coal dust are generated. Especially underground, coal dust concentrations can sometimes reach levels exceeding 1,400 mg / m³, making its control and prevention a pressing task for the coal industry.

[0003] The presence of coal dust not only accelerates the wear of mechanical equipment but, more importantly, poses a serious threat to miners' health, increasing the risk of occupational diseases such as pneumoconiosis. According to the latest statistics, as of the end of 2021, the cumulative number of reported cases of occupational diseases has exceeded 900,000, of which cases of occupational pneumoconiosis account for approximately half of the total reported occupational diseases. This data highlights the urgent need to address the pollution caused by coal dust to the environment and human health in order to protect workers' health and reduce the incidence of occupational diseases. Therefore, effective dust control is of great importance. Currently, commonly used dust suppressants do not produce noticeable changes in surface color or state before and after spraying, making it difficult to verify the application and effectiveness of dust suppressants and preventing automated spraying through remote identification. Therefore, research on visual automatic identification of dust suppressants has important environmental and economic significance.

[0004] Aggregation-induced emission (AIE) materials are novel luminescent materials that emit weak or no light in a dispersed state but intense light in an aggregated state. They offer the advantages of low background signal and intense light in a solid or aggregated state. Ionic AIE dust suppressants are characterized by good water solubility, a high melting point, high stability, and environmental friendliness, meeting the requirements for environmentally friendly dust suppressants in my country's railway industry standard TB / T 3210.1-2020.

[0005] Fluorescent materials reported in recent years are mainly used in the fields of biological imaging, optical materials, fluorescent probes, etc. For example, patent CN110194777A discloses an ionic aggregation-induced luminescence group and its preparation method and application. The structural formula of the ionic aggregation-induced luminescence group is Wherein, each R is independently selected from H, alkyl, unsaturated alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl, and heteroaryl; X is an anion; this ionic aggregation-induced luminophore can be used to distinguish between various solvents with different hydrogen bond donation capacities, and can also be used as a wash-free imaging agent for biological samples and as a fluorescent probe with excellent photostability. However, the use of fluorescent materials as dust suppressants for railway coal transportation has not been reported. The use of identifiable dust suppressants for railway coal transportation will greatly simplify the difficulty of dust suppressant spray quality inspection, reduce the risks of traditional on-board inspection, lower labor costs, improve inspection efficiency, and enable automated remote inspection. Summary of the Invention

[0006] In view of the problem of visual dust suppressants in the prior art, the present invention provides an aggregation-induced luminescence dust suppressant based on thiazolyl and thiazolyl bridged imidazole to solve the above problems. The present invention uses the aggregation-induced luminescence dust suppressant based on thiazolyl and thiazolyl bridged imidazole as a dust suppressant for railway coal transportation and sprays it on the surface of coal. The luminescent material in the dust suppressant can emit fluorescence under the action of ultraviolet light, and the fluorescence is enhanced as the water in the dust suppressant evaporates. The fluorescence intensity is linearly related to the polymer content in the dust suppressant, the dust suppressant concentration, and the uniformity. It shows a bright yellow to green luminescence on the coal surface, achieving the effect of being visible to the naked eye from a distance. The fluorescent identification material has halogen ions, exhibits good water solubility and biocompatibility, and has the characteristics of high boiling point, high luminescence intensity, no metal ions, low toxicity, simple synthesis, and low price. It can be well applied to railway coal transportation and can achieve the effect of remote detection.

[0007] In a first aspect, the present invention provides a compound represented by the following formula I:

[0008]

[0009] in,

[0010] R is selected from H, CH3 or CH3(CH2) n , n is 1 to 17;

[0011] X is selected from Cl, Br, I, F, CH3COO, CF3COO, CF3SO2, (CF3SO2)N, SbF6, BF4, B(C6F6)4 or C4F9.

[0012] Furthermore, R is selected from n-propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl; and X is selected from Cl, Br or I.

[0013] Further, selected from the following compounds:

[0014]

[0015] In a second aspect, the present invention provides a method for synthesizing a compound of formula I, comprising the following reaction:

[0016]

[0017] The preparation method is:

[0018] Methylimidazole aldehyde and dithiooxamide are used as raw materials, and a compound of formula II is obtained under the action of catalyst I; and then a compound of formula I is obtained under the action of catalyst II.

[0019] Further, the compound of formula II is prepared as follows:

[0020] Methylimidazole aldehyde and dithiooxamide are mixed and dissolved in solvent I. Under the action of catalyst I, the mixture is heated under reflux. After the reaction is complete, rotary evaporation and extraction are performed. The organic layer is dried over anhydrous Na2SO4, filtered, and then solid-liquid separation is performed. The solid is separated by silica gel column chromatography or recrystallized to obtain a compound of formula II. The catalyst I is selected from acetic acid; and the solvent I is selected from at least one of anhydrous methanol, anhydrous ethanol, acetonitrile, chloroform, n-propanol, or N,N-dimethylformamide.

[0021] Furthermore, the amount of the catalyst I used is 0.5 to 15 mol% based on the amount of methylimidazole aldehyde fed.

[0022] Furthermore, the heating reflux time is 5 to 72 hours.

[0023] Furthermore, the compound of formula I is prepared as follows: the compound of formula II and the compound of formula III are mixed and dissolved in solvent II, catalyst II is added, and stirred. After the reaction is completed, the mixture is cooled and separated by silica gel column chromatography or recrystallized to obtain a thiazolylthiazole-bridged imidazole organic salt 1, that is, an aggregation-induced luminescence dust suppressant based on thiazolylthiazole-bridged imidazole; wherein the definitions of R and X in the compound of formula III are the same as those of the compound of formula I.

[0024] Furthermore, the catalyst II is acetic acid; and the solvent II is at least one of anhydrous methanol, acetonitrile, ethanol or N,N-dimethylformamide.

[0025] Furthermore, the molar ratio of the compound of formula II, halogenated hydrocarbon, and catalyst II is 1:1-2:0.001-0.006.

[0026] Furthermore, the stirring temperature is 20 to 160° C., and the stirring time is 4 to 48 hours; and the developing solvent of the silica gel column chromatography is a mixed solvent of dichloromethane and methanol in a volume ratio of 30:1.

[0027] In a third aspect, the present invention provides a use of a compound of formula I as an identification agent in the field of visual detection of dust suppressants for storage yards or deserts.

[0028] In a fourth aspect, the present invention provides a specific method for using the compound of formula I as a dust suppressant, as follows:

[0029] (1) adding the compound of formula I into water, stirring and mixing to obtain an aqueous solution of the compound of formula I having a concentration of 0.0010 to 0.0015 kg / kg;

[0030] (2) The aqueous solution of the compound of formula I obtained in step (1) was diluted with water at a rate of 2 L / min. 3 The spray amount is sprayed onto the coal surface. After spraying, it is irradiated with a 365nm ultraviolet lamp. The uniformity of the dust suppressant spraying is observed based on the fluorescence intensity and distribution of the dust suppressant.

[0031] The beneficial effects of the present invention are:

[0032] (1) The compound of formula I provided by the present invention is an aggregation-induced emission molecule based on thiazolyl-thiazole-bridged imidazole, which is a new type of green fluorescent dust suppressant with good light / thermal stability and low background fluorescence interference. The synthesis route of the dust suppressant molecule is short, the process is simple, and it is easy to operate.

[0033] (2) The compound of formula I provided by the present invention has obvious advantages when applied to the detection of dust suppressants for railway coal transportation: the existing detection of dust suppressants for railway coal transportation requires on-board inspection, which is risky, time-consuming and labor-intensive, and not conducive to remote rapid detection; while the compound of formula I prepared by the present invention has good solubility, small dosage, and can emit bright green or yellow fluorescence, with an emission wavelength generally between 520nm and 590nm. It does not emit light under natural light, but emits strong light under ultraviolet light, with little photodamage and easy identification. Moreover, common substances emit blue light or no light, resulting in less interference. Therefore, yellow and green fluorescent dust suppressants are less affected by environmental factors.

[0034] (3) Before spraying the aqueous solution of the compound of Formula I, there was no fluorescence in the 400-600 nm range, and the coal seam appeared black. After spraying the aqueous solution of the compound of Formula I, green fluorescence appeared at 530 nm. The fluorescence increased as the dust suppressant gradually lost water. The fluorescence wavelength did not change with the concentration of the dust suppressant, and the effect was visible to the naked eye. This made it easy for remote instruments to identify the quality of the dust suppressant spraying.

[0035] (4) The compound of formula I provided by the present invention is suitable for various scenarios such as daytime, nighttime, indoors and outdoors during the railway coal transportation process, and exhibits the characteristics of constant luminous color, strong anti-interference ability, high sensitivity (within 0.2 seconds), and fast response, and can be well applied in the railway coal transportation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0037] Figure 1 This is the HNMR spectrum of the compound of formula II prepared in Example 1 of the present invention.

[0038] Figure 2 The CNMR spectrum of the compound of formula II prepared in Example 1 of the present invention is shown in FIG.

[0039] Figure 3 These are test images of an application example of the present invention. The left image shows a coal seam under natural light; the middle image shows a coal seam sprayed with the dust suppressant prepared in Example 1 (a green fluorescent dust suppressant) under 400nm ultraviolet light; and the right image shows a coal seam sprayed with the dust suppressant prepared in Example 1 (a yellow fluorescent dust suppressant). DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0041] Example 1

[0042] (1) Preparation of compound of formula II

[0043] In a 100 mL round-bottom flask, 550 mg (5 mmol) of 1-methylimidazole aldehyde, 1.2 g (10 mmol) of dithiooxamide, 20 mL of anhydrous ethanol, and 0.04 mL of acetic acid were added. The mixture was heated to reflux at 90° C. for 6 h, cooled, and the solvent was removed by rotary evaporation. The residue was extracted with dichloromethane and 2% sodium bicarbonate solution. The organic layer was dried over anhydrous Na2SO4, filtered, and concentrated. The residue was passed through a silica gel column (PE:EtOAc=3:1) to obtain 1.391 g of a yellow solid, i.e., the compound of formula II, with a yield of 81.8%.

[0044] Melting point Mp = 261°C.

[0045] 1 H NMR (400 MHz, DMSO-d 6)δ8.44(s,1H),7.79(d,J=1.6Hz,1H),7.75(d,J=7.26Hz,1H),7.72(d,J=1.6Hz,1H),7.41-7.48(m,2H),4.04(s,3H),3.68(s,3H)ppm.

[0046] 13 C NMR (100MHz, DMSO-d6): δ170.84,140.49,139.45,126.95,125.64,123.4,122.92,122.62,111.35,36.22and 31.45ppm.

[0047] MALDI TOF-MS, C 13 H 14 N5S[M] + : Calculated value 272.0964, found value 272.0967.

[0048] (2) Compounds Preparation

[0049] Intermediate I (0.302 g, 1.10 mmol) was placed in a 100 mL flask with a magnetic stirrer. The mixture was dissolved in 20 mL of acetonitrile. Ioheptane (0.18 mL, 1.10 mmol) and acetic acid (0.0011 mmol) were then added. The mixture was heated to reflux at 100°C for 12 h, cooled to room temperature, and analyzed by thin-layer chromatography (TLC). The complete disappearance of Intermediate I confirmed the completion of the reaction. Column chromatography with a developing solvent of dichloromethane:methanol (30:1) was performed to obtain 0.204 g of a yellow powder, the target compound, in a 67.54% yield.

[0050] Example 2

[0051] (1) Preparation of compound of formula II

[0052] To a 100 mL round-bottom flask were added 550 mg (5 mmol) of 1-methylimidazole aldehyde, 1.2 g (10 mmol) of dithiooxamide, 20 mL of acetonitrile, and 0.04 mL of acetic acid. The mixture was heated under reflux at 90° C. for 6 h, cooled, and the solvent was removed by rotary evaporation. The residue was extracted with dichloromethane and 2% sodium bicarbonate solution. The organic layer was dried over anhydrous Na2SO4, filtered, and concentrated. The residue was passed through a silica gel column (PE:EtOAc=3:1) to obtain 1.465 g of a yellow solid, i.e., the compound of formula II, with a yield of 83.7%.

[0053] (2) Compounds Preparation

[0054] Intermediate I (0.302 g, 1.10 mmol) was placed in a 100 mL flask with a magnetic stirrer. The mixture was dissolved in 20 mL of acetonitrile. Propane bromohydrate (0.099 mL, 1.10 mmol) and acetic acid (0.0011 mmol) were then added. The mixture was heated to reflux at 100°C for 12 h, cooled to room temperature, and analyzed by thin-layer chromatography (TLC). The complete disappearance of intermediate I confirmed the completion of the reaction. Column chromatography with a developing solvent of dichloromethane:methanol (30:1) was performed to obtain 0.255 g of a yellow powder, the target compound, in an 84.44% yield.

[0055] Application Examples

[0056] The application of the aggregation-induced luminescence dust suppressant based on thiazolothiazole-bridged imidazole prepared in Example 1 in the field of visual detection in storage yards or deserts is as follows:

[0057] (1) Add 240 g of identification agent to 200 kg of water and stir for 15 min to obtain a dust suppressant aqueous solution;

[0058] (2) According to 2L / m 2 Spray the dust suppressant aqueous solution onto the surface of the coal being transported by the train. Irradiate with a 365nm ultraviolet lamp and judge whether the dust suppressant has been sprayed and whether the spraying is uniform based on the intensity and distribution of the fluorescence emitted by the dust suppressant.

[0059] (3) Fluorescence spectrum test method

[0060] Use a pipette to transfer 3 mL of an aqueous solution of an aggregation-induced luminescence dust suppressant based on thiazolyl-thiazole-bridged imidazole into a 1 cm cuvette. Use a microinjector to add different volumes of anion solution to meet different concentration requirements. Mix thoroughly and let it stand for 2 minutes before testing. The excitation wavelength of all test substances was set to 365-460 nm. The absolute quantum efficiency tester was used for detection. The results are detailed in the table. Figure 3 .

[0061] Although the present invention has been described in detail with reference to the accompanying drawings and in combination with preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any person skilled in the art who can easily conceive of changes or substitutions within the technical scope disclosed in the present invention shall be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope of protection described in the claims.

Claims

1. Compound of formula I: ； in, R is selected from H, CH3 or CH3(CH2) n , n is 1~17; X is selected from Cl, Br, I, F, CH3COO, CF3COO, CF3SO2, (CF3SO2)N, SbF6, BF4, B(C6F6)4 or C4F9.

2. The compound of formula I according to claim 1, wherein The R is selected from n-propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl; and X is selected from Cl, Br or I.

3. The compound of formula I according to claim 1, wherein Selected from the following compounds: or .

4. A method for preparing the compound of formula I according to claim 1, characterized in that: The reaction is as follows: ； The preparation method is: Methylimidazole aldehyde and dithiooxamide are used as raw materials, and a compound of formula II is obtained under the action of catalyst I; then a compound of formula I is obtained under the action of catalyst II; wherein R and X have the same definitions as those of the compound of formula I; The compound of formula II is prepared as follows: Methylimidazole aldehyde and dithiooxamide are mixed and dissolved in solvent I, and heated under reflux in the presence of catalyst I. After the reaction is complete, the mixture is rotary evaporated and extracted. The organic layer is dried over anhydrous Na2SO4, filtered, and then the solid-liquid separation is carried out. The solid is separated by silica gel column chromatography or recrystallized to obtain a compound of formula II; the catalyst I is selected from acetic acid; and the solvent I is selected from at least one of anhydrous methanol, anhydrous ethanol, acetonitrile, chloroform, n-propanol, or N,N-dimethylformamide. The compound of formula I is prepared as follows: a compound of formula II and a compound of formula III are mixed and dissolved in a solvent II, a catalyst II is added, and the mixture is stirred. After the reaction is completed, the mixture is cooled and separated by silica gel column chromatography or recrystallized to obtain a thiazolylthiazole-bridged imidazole organic salt 1, i.e., an aggregation-induced luminescence dust suppressant based on a thiazolylthiazole-bridged imidazole; the catalyst II is acetic acid; wherein the definitions of R and X in the compound of formula III are the same as those of the compound of formula I.

5. The method according to claim 4, wherein The amount of the catalyst I is 0.5-15 mol% based on the amount of methylimidazole aldehyde charged.

6. The method according to claim 4, wherein The molar ratio of the compound of formula II, halogenated hydrocarbon and catalyst II is 1:1-2:0.001-0.

006.

7. Use of the compound of formula I as claimed in claim 1 as a dust suppressant.

8. A specific method for using the compound of formula I as claimed in claim 1 as a dust suppressant, which is as follows: (1) adding the compound of formula I into water and stirring and mixing to obtain an aqueous solution of the compound of formula I with a concentration of 0.0010 to 0.0015 kg / kg; (2) The aqueous solution of the compound of formula I obtained in step (1) was diluted with water at a rate of 2 L / m 3 The spray amount is sprayed onto the coal surface. After spraying, it is irradiated with a 365nm ultraviolet lamp. The uniformity of the dust suppressant spraying is observed based on the fluorescence intensity and distribution of the dust suppressant.

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