Aggregation-induced emission dust suppressant based on thiazolothiazole bridged imidazole

Abstract

The invention relates to an aggregation-induced emission dust suppressant based on thiazolothiazole bridged imidazole, and belongs to the technical field of dust suppressants. In the formula I, R is selected from H, CH3 or CH3 (CH2) n, and n ranges from 1 to 17; x is selected from the group consisting of Cl, Br, I, F, CH3COO, CF3COO, CF3SO2, (CF3SO2) N, SbF6, BF4, B (C6F6) 4 or C4F9. The aggregation-induced emission dust suppressant based on thiazolothiazole bridged imidazole is used as a dust suppressant for railway coal transportation and is sprayed on the surface of coal, and the luminescent material can emit fluorescence in the dust suppressant under the action of ultraviolet light, so that the effect of long-distance visible with naked eyes is achieved. In addition, the polymer has the characteristics of good water solubility and biocompatibility, high boiling point, high luminous intensity, no metal ions, low toxicity, simple synthesis, low price and the like, can be well applied to railway coal transportation, and can achieve a remote detection effect.

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 thiazolylthiazole-bridged imidazole. Background Art

[0002] In my country's energy structure, coal resources still occupy a pivotal position. However, in view of the country's increasingly strict supervision of environmental pollution prevention and control, it is particularly important to achieve clean production in the coal industry. Throughout the life cycle of coal, including mining, crushing, screening, transportation, storage and coal rock crushing, a large amount of coal dust will be generated. Especially in underground environments, the concentration of coal dust can sometimes even reach a high level of more than 1,400 mg / m3, which makes the control and prevention of coal dust an urgent task facing the coal industry.

[0003] The presence of coal dust not only accelerates the wear of mechanical equipment, but more importantly, it poses a serious threat to the health of miners and increases the risk of occupational diseases such as pneumoconiosis. According to the latest statistics, as of the end of 2021, the cumulative reported cases of occupational diseases have exceeded 900,000, of which occupational pneumoconiosis cases account for about half of the total number of occupational disease reports. This data emphasizes the urgent need to address the pollution problems caused by coal dust to the environment and human health in order to protect the health of workers and reduce the occurrence of occupational diseases. Therefore, effective dust suppression is of great significance. Up to now, the commonly used dust suppressants have no obvious color or state changes on the surface of objects before and after spraying, which makes it more difficult to check the spraying and effect of dust suppressants, and it is impossible to realize the automatic spraying of dust suppressants through remote identification. Therefore, the research on visual automatic identification of dust suppressants has important environmental significance and economic value.

[0004] Aggregation-induced luminescence material is a new type of luminescent material that emits weak or no light in a dispersed state, but emits strong light in an aggregated state. It has the advantages of weak background signal and strong light in a solid or aggregated state. Ionic aggregation-induced luminescence dust suppressants have the characteristics of good water solubility, high melting point, high stability and environmental protection, which meets the requirements of my country's railway industry standard TB / T 3210.1-2020 for environmentally friendly dust suppressants.

[0005] In recent years, fluorescent materials reported 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; the ionic aggregation-induced luminophore can be used to distinguish a variety of solvents with different hydrogen bond donation capabilities, and can also be used as a wash-free imaging agent for biological samples and as a fluorescent probe with good photostability. However, the use of fluorescent materials for railway coal transportation dust suppressants has not been reported. The use of identifiable dust suppressants for railway coal transportation will greatly reduce the difficulty of dust suppressant spraying quality inspection, reduce the risk of traditional pedaling inspection, reduce labor costs, improve detection efficiency, and realize automated remote detection. Summary of the invention

[0006] In view of the problem of visualized 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 concentration of the dust suppressant, and the uniformity. Bright yellow to green light is presented on the surface of the coal, achieving the effect of being visible to the naked eye at a long distance. The fluorescent identification material has halogen ions, exhibits good water solubility and biocompatibility, 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 as shown in 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, wherein the reaction is as follows:

[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] The methylimidazole aldehyde and dithiooxamide are mixed and dissolved in a solvent I, and heated under reflux under the action of a catalyst I. After the reaction is complete, the organic layer is rotary evaporated and extracted, and the organic layer is dried over anhydrous Na2SO4, filtered, and then the solid-liquid is separated. 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 thiazolyl and thiazolyl bridged imidazole organic salt 1, that is, an aggregation-induced luminescence dust suppressant based on thiazolyl and thiazolyl 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; 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, the halogenated hydrocarbon, and the 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; 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, which is 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 with 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 / m 3 The spray amount is sprayed onto the coal surface. After spraying, it is irradiated with a 365nm ultraviolet lamp. The spraying uniformity of the dust suppressant 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 small 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 pedaling inspection, which is risky, time-consuming and labor-intensive, and is not conducive to remote rapid detection; while the compound of formula I prepared by the present invention has good solubility, small dosage, can emit bright green or yellow fluorescence, and the emission wavelength is generally between 520nm and 590nm. It does not emit light under natural light, but emits strong light under ultraviolet light, has little light damage, is easy to identify, and common substances emit blue light or no light, with 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 is no fluorescence in the range of 400nm-600nm, and the coal seam appears black. After spraying the aqueous solution of the compound of formula I, green fluorescence appears at 530nm, and the fluorescence increases as the dust suppressant gradually loses water. The fluorescence wavelength does not change with the concentration of the dust suppressant, and the effect of naked eye visibility can be achieved. In this way, it is easy for remote instruments to identify the spraying quality of the dust suppressant.

[0035] (4) The compound of formula I provided by the present invention is suitable for various scenes such as daytime, nighttime, indoors and outdoors during railway coal transportation, 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 railway coal transportation. 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying 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 It is the CNMR spectrum of the compound of formula II prepared in Example 1 of the present invention.

[0039] Figure 3 The left picture is a display picture of the coal seam under natural light; the middle picture is a coal seam sprayed with the dust suppressant prepared in Example 1 (green fluorescent dust suppressant) under 400nm ultraviolet light; the right picture is a coal seam sprayed with the dust suppressant prepared in Example 1 (yellow fluorescent dust suppressant). DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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] Take intermediate I (0.302g, 1.10mmol) and add it to a 100mL flask. Add a magnetic bar and dissolve it in 20mL acetonitrile solution. Add iodoheptane (0.18mL, 1.10mmol) and acetic acid (0.0011mmol). After heating and reflux at 100℃ for 12h, cool it to room temperature. Thin layer chromatography detection shows that intermediate I disappears completely, proving that the reaction is complete. Column chromatography separation and purification are performed. The developing solvent is dichloromethane: methanol (30:1) to obtain 0.204g of yellow powder, that is, the target compound is obtained. The yield is 67.54%.

[0050] Example 2

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

[0052] 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 acetonitrile, 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 1.465 g of a yellow solid, i.e., the compound of formula II, with a yield of 83.7%.

[0053] (2) Compounds Preparation

[0054] Take intermediate I (0.302g, 1.10mmol) and add it to a 100mL flask. Add a magnetic bar and dissolve it in 20mL acetonitrile solution. Add bromopropane (0.099mL, 1.10mmol) and acetic acid (0.0011mmol). After heating and reflux at 100℃ for 12h, cool it to room temperature. Thin layer chromatography detection shows that intermediate I disappears completely, proving that the reaction is complete. Column chromatography separation and purification are performed. The developing solvent is dichloromethane: methanol (30:1) to obtain 0.255g of yellow powder, that is, the target compound is obtained. The yield is 84.44%.

[0055] Application Examples

[0056] The application of the aggregation-induced luminescence dust suppressant based on thiazolylthiazole-bridged imidazole prepared in Example 1 in the field of visual detection in a dump or desert is as follows:

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

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

[0059] (3) Fluorescence spectrum test method

[0060] Use a pipette to transfer 3 mL of the aqueous solution of the thiazolyl-thiazole-bridged imidazole-based aggregation-induced luminescence dust suppressant into a 1 cm cuvette, and use a microinjector to add different volumes of anion solution to meet different concentration requirements. Mix thoroughly and let stand for 2 minutes before testing. The excitation wavelength of all test objects is set to 365-460 nm. Use a Cary Eclipse absolute quantum efficiency tester for detection. For details, see Figure 3 .

[0061] Although the present invention has been described in detail by referring to the accompanying drawings and in combination with the 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 these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection described in the claims.

Claims

1. Compounds of formula I: in, 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.

2. The compound of formula I according to claim 1, characterized in that 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, characterized in that Selected from the following compounds:

4. A method for preparing the compound of formula I as claimed in 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 the definitions of R and X are the same as those of the compound of formula I.

5. The method according to claim 4, characterized in that The compound of formula II is prepared as follows: The methylimidazole aldehyde and dithiooxamide are mixed and dissolved in a solvent I, and heated under reflux under the action of a catalyst I. After the reaction is complete, the organic layer is rotary evaporated and extracted, and the organic layer is dried over anhydrous Na2SO4, filtered, and then the solid-liquid is separated. 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.

6. The method according to claim 5, characterized in that The amount of the catalyst I used is 0.5 to 15 mol% based on the amount of methylimidazole aldehyde charged.

7. The method according to claim 4, characterized in that 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 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.

8. The method according to claim 7, characterized in that The molar ratio of the compound of formula II, the halogenated hydrocarbon and the catalyst II is 1:1-2:0.001-0.

006.

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

10. A specific method of 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, 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 spraying uniformity of the dust suppressant is observed based on the fluorescence intensity and distribution of the dust suppressant.

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