A metal organic framework material for quick detection of acetylene and its preparation method, and its application in detection of dissolved acetylene in transformer oil

Abstract

The invention discloses a metal organic framework material for quickly detecting acetylene and a preparation method thereof, and an application of the metal organic framework material for detecting dissolved acetylene in transformer oil. The metal organic framework material is composed of a dicarboxylic acid ligand with a flexible thiomethyl group and a metal ion of group IB to form a metal organic framework, and then the soft functional group thiomethyl of the side chain stably adsorbs the metal ions of group VIII to fix them in the metal organic framework, and can quickly adsorb and catalyze acetylene to polymerize acetylene. The polymerized acetylene causes the metal organic framework to undergo a visual color change, so that the metal organic framework can be used as a colorimetric sensor to realize rapid detection of acetylene. Through solvent thermal reaction and soaking reaction, the preparation process does not require harsh reaction conditions and complex processes, and the method is simple. The dissolved acetylene in the transformer oil can be conveniently and quickly detected by colorimetry; the detection limit reaches 4.1ppm, overcoming the problems of the traditional transformer detection process being cumbersome, time-consuming, and costly, and can realize real-time monitoring.

Description

Technical Field

[0001] The invention belongs to the technical field of novel metal organic materials, and in particular relates to a metal organic framework material for quickly detecting acetylene and a preparation method thereof, and an application of the material in detecting dissolved acetylene in transformer oil. Background Art

[0002] Oil-immersed power transformers are mainly used in power systems, accounting for 90% of the transformer market. The safe operation of transformers directly affects the stability of the power system and the safety of electricity use, and has a great impact on industrial production and human life. However, the long-term operation of transformers will lead to some insulation defects. The excessive temperature or partial discharge caused by these insulation defects will decompose the insulating oil into various volatile gases, such as H2, CO, CO2, C2H2, CH4, C2H4, C2H6, etc. As these gases continue to dissolve in the transformer oil, the insulation performance of the transformer oil also decreases, which poses a great threat to the transformer.

[0003] Among them, the overheating and discharge faults of oil-immersed transformers can be identified by detecting dissolved acetylene. Therefore, the development of sensitive and effective sensing materials for dissolved acetylene detection is crucial to evaluate the operating quality of oil-immersed power transformers.

[0004] In recent years, the commonly used methods for detecting dissolved gases in insulating oil include gas chromatography (GC), metal oxide semiconductor sensing technology, fiber Bragg grating sensing technology, Raman spectroscopy, infrared absorption spectroscopy and photoacoustic spectroscopy. When these methods are used for detection, the gas to be detected must first be separated and extracted from oil and large equipment before the gas to be detected can be detected. The operation is cumbersome and greatly limits the field application.

[0005] Metal-organic frameworks (MOFs) are a class of porous crystalline materials assembled from metal ions / clusters and organic linkers through coordination bonds. MOFs are characterized by high porosity, high specific surface area, and structural tunability, and are considered to be a promising platform for gas adsorption and separation, catalysis, drug delivery, and sensing. Many MOFs have been used as sensors to detect various volatile organic compounds or for acetylene adsorption and separation, but few have been applied to acetylene detection, especially for direct detection of dissolved acetylene; and compared with instrumental detection methods, naked eye colorimetric detection is the simplest and most ideal acetylene detection method for field applications. Therefore, further research is needed for the rapid detection of dissolved acetylene. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the first object of the present invention is to provide a metal organic framework material for quickly detecting acetylene. Group VIII metal ions are fixed in the MOF material with flexible thiomethyl pendants on the side chains, which can achieve rapid catalytic polymerization of acetylene dissolved in liquid. The polymerization product causes a specific change in the color of the MOF, thereby realizing rapid and easy monitoring of acetylene dissolved in the liquid.

[0007] The second object of the present invention is to provide a method for preparing the metal organic framework material for quick detection of acetylene.

[0008] The third object of the present invention is to provide an application of the above-mentioned metal organic framework material for quickly detecting acetylene for detecting acetylene dissolved in transformer oil.

[0009] One of the purposes of the present invention can be achieved by adopting the following technical solution:

[0010] A metal organic framework material for quick detection of acetylene, comprising a metal organic framework composed of an organic ligand of a structure shown in formula I and a group IB metal ion, and a group VIII metal ion fixed in the metal organic framework; the group VIII metal ion is coordinated and connected with a methylthio group in the organic ligand of the structure shown in formula I, and fixed in the metal organic framework;

[0011]

[0012] Among them, R1, R2, R3, and R4 are H, C1-C3 alkyl, halogen, or methylthio, and at least one of R1, R2, R3, and R4 is methylthio.

[0013] Furthermore, in the metal-organic framework composed of the organic ligand of the structure shown in Formula I and the Group IB metal ion, the Group IB metal ion is coordinated with the carboxyl group of the organic ligand of the structure shown in Formula I in the form of a M6O4(OH)4 cluster to form an fcu topological structure composed of tetrahedral and octahedral cages, wherein M is a Group IB metal ion.

[0014] Furthermore, the Group IB metal ion is a zirconium ion; and the Group VIII metal ion is a platinum ion.

[0015] The second purpose of the present invention can be achieved by adopting the following technical solutions:

[0016] A method for preparing a metal organic framework material for quick detection of acetylene comprises the following steps:

[0017] An organic ligand having a structure shown in formula I, a group IB metal ion precursor and a regulator are mixed and added to a first solvent for dissolution; a solvent thermal reaction is then carried out under closed conditions. After the reaction is completed, solid-liquid separation is performed to obtain a solid product, and the solid product is then added to a second solvent in which a group VIII metal ion precursor is dissolved for reaction to obtain the metal organic framework material for quick detection of acetylene.

[0018] Furthermore, the Group IB metal ion precursor is one or a combination of two or more of chlorides, nitrates, acetates and hydrates of Group IB metal ions; the molar ratio of the organic ligand having the structure shown in Formula I to the Group IB metal ion precursor is 1:(1.5-2.5).

[0019] Furthermore, the first solvent is one or a combination of two or more selected from N,N-dimethylformamide, N,N-diethylformamide, dioxane, and dimethyl sulfoxide; the second solvent is one or a combination of two or more selected from acetonitrile, methanol, tetrahydrofuran, N,N-dimethylformamide, and N,N-diethylformamide; and the molar volume ratio of the organic ligand having the structure shown in Formula I to the first solvent is 1 mmol:(10-200) ml.

[0020] Furthermore, the regulator is one or a combination of two or more of benzoic acid, formic acid, acetic acid, propionic acid, acrylic acid, butyric acid and hydrochloric acid; the molar ratio of the IB group metal ion precursor to the regulator is 1:(1-50).

[0021] Further, the Group VIII metal ion precursor is one or a combination of two or more of chlorides, nitrates, acetates and hydrates of Group VIII metal ions;

[0022] The solid product is added to a second solvent in which a Group VIII metal ion precursor is dissolved to react, wherein the mass volume ratio of the solid product to the second solvent in which the Group VIII metal ion precursor is dissolved is 1 mg:(0.1-1) mL; and the concentration of the Group VIII metal ion precursor in the second solvent in which the Group VIII metal ion precursor is dissolved is 0.01-0.1 mmol / mL.

[0023] Furthermore, the solvothermal reaction is carried out at 90-150° C. for 6-96 hours; and the solid product and the Group VIII metal ion precursor are dissolved in the second solvent and reacted at 10-80° C. for 12-96 hours.

[0024] The third object of the present invention can be achieved by adopting the following technical solutions:

[0025] Application of any of the above-mentioned metal organic framework materials for quick detection of acetylene in detecting dissolved acetylene in transformer oil.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. A metal organic framework material for rapid detection of acetylene of the present invention comprises a metal organic framework composed of a dicarboxylic acid ligand with a flexible thiomethyl group and a group IB metal ion, wherein the soft functional group thiomethyl group of the side chain stably adsorbs the group VIII metal ion to fix it into the metal organic framework, and can rapidly adsorb and catalyze acetylene to polymerize acetylene, and the polymerized acetylene causes a visual color change in the metal organic framework, so that the metal organic framework material for rapid detection of acetylene can be used as a colorimetric sensor to realize rapid detection of acetylene.

[0028] 2. A method for preparing a metal organic framework material for rapid detection of acetylene of the present invention comprises constructing a metal organic framework by a solvothermal reaction, and then utilizing the soft functional group thiomethyl on the side chain of the metal organic framework to stably adsorb group VIII metal ions, and then synthesizing a metal organic framework material for rapid detection of acetylene capable of catalytic polymerization of acetylene. Solvothermal construction of a metal organic framework is simple and convenient, and does not require harsh reaction conditions and complex processes; the metal organic framework and group VIII metal ions are mixed and soaked in a solution to fix the group VIII metal ions into the metal organic framework, and the method is simple.

[0029] 3. The present invention applies a metal organic framework material for quickly detecting acetylene in detecting acetylene dissolved in transformer oil. Acetylene dissolved in the transformer oil can react with the metal organic framework material, and the metal organic framework material undergoes a color change visible to the naked eye. Therefore, the dissolved acetylene in the transformer oil can be detected quickly and conveniently by colorimetry. The present invention overcomes the problems of the traditional transformer detection process being cumbersome, time-consuming, and costly, which limits its detection frequency and makes it difficult to monitor the transformer operating status in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the synthesis process of the metal organic framework material Pt@UiO-68-2SMe for rapid detection of acetylene in Example 1 of the present invention;

[0031] Figure 2 Appearance and color diagram of UiO-68-2SMe (A) and Pt@UiO-68-2SMe (B) prepared in Example 1 of the present invention;

[0032] Figure 3 X-ray powder diffraction patterns of UiO-68-2SMe and Pt@UiO-68-2SMe prepared in Example 1 of the present invention;

[0033] Figure 4Schematic diagram of the structure of the octahedron (a) and tetrahedron (b) cages in UiO-68-2SMe prepared in Example 1 of the present invention;

[0034] Figure 5 Infrared spectra of UiO-68-2SMe and Pt@UiO-68-2SMe prepared in Example 1 of the present invention;

[0035] Figure 6 This is a SEM image of Pt@UiO-68-2SMe prepared in Example 1 of the present invention;

[0036] Figure 7 This is the EDS image of Pt@UiO-68-2SMe prepared in Example 1 of the present invention;

[0037] Figure 8 XPS spectra of the S2p region of UiO-68-2SMe and Pt@UiO-68-2SMe prepared in Example 1 of the present invention;

[0038] Fig. 9 High-resolution Pt 4fXPS spectrum of Pt@UiO-68-2SMe prepared in Example 1 of the present invention;

[0039] Fig.10 Raman spectra of UiO-68-2SMe and Pt@UiO-68-2SMe prepared in Example 1 of the present invention;

[0040] Fig.11 This is a color diagram of UiO-68-2SMe prepared in Example 1 of the present invention after being immersed in a 70°C C2H2 aqueous solution and purged in C2H2 gas;

[0041] Fig.12 This is a Raman spectrum of UiO-68-2SMe prepared in Example 1 of the present invention after being immersed in a 70°C C2H2 aqueous solution and purged in C2H2 gas;

[0042] Fig.13 This is the infrared spectrum of UiO-68-2SMe prepared in Example 1 of the present invention after being immersed in a 70°C C2H2 aqueous solution and purged in C2H2 gas;

[0043] Fig.14 This is a color diagram of the Pt@UiO-68-2SMe crystal prepared in Example 1 of the present invention after being purged in pure gases acetylene (C2H2), ethane (C2H6), ethylene (C2H4), hydrogen (H2), nitrogen (N2), and carbon dioxide (CO2) for 2 hours;

[0044] Fig.15The color change diagram of Pt@UiO-68-2SMe prepared in Example 1 of the present invention using pure C2H2 to purge the body for 30 minutes;

[0045] Fig.16 The Raman spectrum of Pt@UiO-68-2SMe prepared in Example 1 of the present invention was obtained by using pure C2H2 to purge the body for 30 minutes;

[0046] Fig.17 The color diagram of Pt@UiO-68-2SMe prepared in Example 1 of the present invention is immersed in transformer oil dissolved with acetylene (C2H2), nitrogen (N2), ethylene (C2H4), ethane (C2H6), hydrogen (H2), carbon monoxide (CO), and carbon dioxide (CO2), and heated at 70°C for 15 minutes;

[0047] Fig.18 The color change diagram of Pt@UiO-68-2SMe prepared in Example 1 of the present invention after being immersed in transformer oil containing different C2H2 concentrations (4.1 ppm, 8.2 ppm, 10.3 ppm, 820 ppm) and heated at 70°C for 15 min. DETAILED DESCRIPTION

[0048] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only partial embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0049] The common method of using instruments to measure dissolved gas in transformer insulating oil requires extracting gas from oil and large equipment, which is cumbersome and greatly limits field applications. Naked eye colorimetric detection is the simplest and most ideal acetylene detection method for field applications. The ability to quickly and directly detect dissolved acetylene by colorimetry solves the problem that traditional transformer detection is limited in frequency due to the cumbersome process, long time consumption, and high cost, and that real-time monitoring of transformer operating status has defects.

[0050] Therefore, the present invention provides a metal organic framework material for quick detection of acetylene, the metal organic framework material comprising a metal organic framework composed of an organic ligand of a structure shown in formula I and a group IB metal ion, and a group VIII metal ion fixed in the metal organic framework; the group VIII metal ion is coordinated and connected with a methylthio group in the organic ligand of a structure shown in formula I, and fixed in the metal organic framework;

[0051]

[0052] Among them, R1, R2, R3, and R4 are H, C1-C3 alkyl, halogen, or methylthio, and at least one of R1, R2, R3, and R4 is methylthio.

[0053] The metal organic framework material for quick detection of acetylene uses a dicarboxylic acid ligand with flexible thiomethyl and a metal ion of group IB as a chemical precursor to construct an original metal organic framework, and uses the soft functional group thiomethyl of the side chain of the metal organic framework to stably fix the metal ions of group VIII to obtain the metal organic framework material for quick detection of acetylene synthesized later. The porosity, large specific surface area and catalytic performance of the synthesized original metal organic framework are utilized, and after further fixing the metal ions of group VIII, good gas adsorption performance and catalytic oxidation performance are achieved, and acetylene can be adsorbed in transformer oil with extremely low C2H2 content and catalyzed to undergo polymerization reaction of acetylene, forming a color change that is obviously visible to the naked eye. Therefore, the metal organic framework material for quick detection of acetylene is an excellent colorimetric sensor.

[0054] Preferably, at least two of R1, R2, R3, and R4 are methylthio groups; the methylthio groups can fix the Group VIII metal ions, so the number of methylthio groups has an impact on the number of fixed Group VIII metal ions. Therefore, at least two methylthio groups in R1, R2, R3, and R4 are preferred. However, on the other hand, too many fixed Group VIII metal ions will lead to the narrowing and blockage of the pores of the metal organic framework material for quick detection of acetylene, which is not conducive to the exposure of gas adsorption and catalytic sites, combined with the influence of steric hindrance, etc., so it is further preferred that there are two methylthio groups, and they are located in the para position on the benzene ring, so in one embodiment, R1 and R4 are methylthio groups, and R2 and R3 are H.

[0055] In one embodiment, in the metal-organic framework composed of the organic ligand of the structure shown in Formula I and the Group IB metal ion, the Group IB metal ion is coordinated with the carboxyl group of the organic ligand of the structure shown in Formula I in the form of a M6O4(OH)4 cluster to form an fcu topological structure composed of tetrahedral and octahedral cages, wherein M is a Group IB metal ion.

[0056] Group IB metal ions easily form catalytically active SBU motifs in MOF materials. The metal oxygen clusters of the SBU motifs are in the form of M6O4(OH)4, which can cooperate with 12 connectors, thereby connecting with carboxyl-containing organic ligands to form tetrahedral and octahedral cages, further forming a three-dimensional network of fcu topological structure to form a metal-organic framework.

[0057] In one embodiment, the Group IB metal ion is a zirconium ion; and the Group VIII metal ion is a platinum ion.

[0058] Zirconium ions of group IB are excellent metal ions for forming MOF frameworks, so this application prefers zirconium ions and organic ligands to form original metal-organic frameworks. Group VIII metals have excellent catalytic properties, and platinum metals are widely used in fields such as organic purification. This application fixes platinum in a metal-organic framework, combines the performance of the organic framework material with the catalytic performance of platinum metal, and realizes the adsorption and catalytic oxidation of acetylene gas dissolved in the liquid, and obtains visual results.

[0059] The present invention also provides a method for preparing a metal organic framework material for quickly detecting acetylene, comprising the following steps:

[0060] An organic ligand having a structure shown in formula I, a group IB metal ion precursor and a regulator are mixed and added to a first solvent for dissolution; a solvent thermal reaction is then carried out under closed conditions. After the reaction is completed, solid-liquid separation is performed to obtain a solid product, and the solid product is then added to a second solvent in which a group VIII metal ion precursor is dissolved for reaction to obtain the metal organic framework material for quick detection of acetylene.

[0061] The original MOF is prepared by solvent thermal reaction, which is a mature method for constructing MOF. It is simple and convenient, does not require harsh reaction conditions and complex processes, and can therefore be prepared in large quantities. Then, the soft functional group thiomethyl on the side chain of the prepared original MOF is used to stably adsorb Group VIII metal ions, and the Group VIII metal ions are fixed to the original MOF through post-synthesis to obtain a metal organic framework material that catalyzes acetylene polymerization and quickly detects acetylene. The original MOF and the Group VIII metal ions are mixed and soaked in a solution to fix the Group VIII metal ions into the metal organic framework, and the method is simple.

[0062] In one embodiment, the solvothermal reaction is carried out in a sealed glass tube under an oxyhydrogen flame, and the glass tube is subjected to ultrasonic treatment before the solvothermal reaction.

[0063] In one embodiment, after the solvothermal reaction is completed, solid-liquid separation is performed to obtain a solid product, and the solid product is further subjected to a washing step, wherein all the washing reagents are N,N-dimethylformamide and acetonitrile, and after washing, the solid product is placed in an acetonitrile solution for storage for later use.

[0064] In one embodiment, the IB group metal ion precursor is one or a combination of two or more of chloride, nitrate, acetate and hydrate of the IB group metal ion; the molar ratio of the organic ligand of the structure shown in formula I to the IB group metal ion precursor is 1:(1.5-2.5). Preferably, the IB group metal ion precursor is a chloride of the IB group metal ion, wherein the molar ratio of the organic ligand of the structure shown in formula I to the IB group metal ion precursor is 1:1.8.

[0065] In one embodiment, the first solvent is one or more of N,N-dimethylformamide, N,N-diethylformamide, dioxane, and dimethyl sulfoxide; the second solvent is one or more of acetonitrile, methanol, tetrahydrofuran, N,N-dimethylformamide, and N,N-diethylformamide; the molar volume ratio of the organic ligand of the structure shown in Formula I to the first solvent is 1mmol:(10-200)ml. Preferably, the first solvent is N,N-dimethylformamide; the second solvent is acetonitrile; the molar volume ratio of the organic ligand of the structure shown in Formula I to the first solvent is 1mmol:50ml.

[0066] N, N-dimethylformamide, N, N-diethylformamide, dioxane, and dimethyl sulfoxide are all commonly used solvents in solvothermal reactions. The second solvent can form a complex with the metal ions in the group VIII metal ion precursor and dissolve in the second solvent. Therefore, after the original MOF is added to the second solvent, ligand exchange can occur, so that the methylthio group of the original MOF side chain coordinates with the metal ions in the group VIII metal ion precursor and fixes it in the original MOF structure.

[0067] In one embodiment, the regulator is one or a combination of two or more of benzoic acid, formic acid, acetic acid, propionic acid, acrylic acid, butyric acid and hydrochloric acid; the molar ratio of the Group IB metal ion precursor to the regulator is 1:(1-50).

[0068] The regulator is an organic acid and / or an inorganic acid, which is beneficial to the formation and regularization of the original MOF crystal. Preferably, the regulator is benzoic acid; and the molar ratio of the IB group metal ion precursor to the regulator is 1:19.

[0069] In one embodiment, the Group VIII metal ion precursor is a chloride, a nitrate, or a combination of both of the Group VIII metal ions; wherein the Group VIII metal ion is a +2 valence Group VIII metal ion.

[0070] The solid product is added to a second solvent in which a Group VIII metal ion precursor is dissolved for reaction, wherein the mass volume ratio of the solid product to the second solvent in which a Group VIII metal ion precursor is dissolved is 1 mg: (0.1-1) mL; the concentration of the Group VIII metal ion precursor in the second solvent in which a Group VIII metal ion precursor is dissolved is 0.01-0.1 mmol / mL. Preferably, the Group VIII metal ion precursor is dissolved in the second solvent to form a saturated solution, and then reacts with the original MOF.

[0071] In one embodiment, the solvothermal reaction is carried out at 90-150°C for 6-96 hours; the solid product and the group VIII metal ion precursor are dissolved in the second solvent and reacted at 10-80°C for 12-96 hours. Preferably, the solvothermal reaction is carried out at 130°C for 72 hours; the solid product and the group VIII metal ion precursor are dissolved in the second solvent and reacted at 25°C for 24 hours.

[0072] The present invention provides an application of the above-mentioned metal organic framework material for quickly detecting acetylene in detecting dissolved acetylene in transformer oil.

[0073] The following is a further description with reference to specific embodiments.

[0074] Example 1

[0075] 34 μmol of anhydrous potassium tetrachloride, 19 μmol of an organic ligand of the structure shown in formula I, wherein R1 and R4 are methylthio, R2 and R3 are H, and 660 μmol of benzoic acid were added to a glass tube; 1 mL of DMF was added to the glass tube, and the glass tube was sealed with an oxyhydrogen flame, and after being mixed evenly by ultrasonication for 60 minutes, it was placed in a 130°C oven and heated for 72 hours, and then naturally cooled to room temperature, and filtered to obtain colorless crystals ( Figure 2 A), named UiO-68-2SMe, the crystal was washed three times with N,N-dimethylformamide and acetonitrile; then 5 mg UiO-68-2SMe was immersed in 1.5 mL PtCl2 saturated acetonitrile solution for 24 h, and the metal organic framework material for rapid detection of acetylene was obtained, which was a light yellow crystal ( Figure 2 B), named Pt@UiO-68-2SMe.

[0076] Example 2

[0077] 28.5 μmol of zirconium nitrate pentahydrate, 19 μmol of an organic ligand of the structure shown in formula I, wherein R1 is methylthio, R2 and R3 are H, and R4 is methyl, and 1425 μmol of acetic acid are added to a glass tube; 0.19 mL of DEF is added to the glass tube, and the glass tube is sealed with a hydrogen-oxygen flame, and after being mixed evenly by ultrasonication for 60 minutes, it is placed in a 90°C oven and heated for 96 hours, and then naturally cooled to room temperature, and filtered to obtain crystals, and the crystals are washed three times with N,N-dimethylformamide and acetonitrile; then 5 mg of the above crystals are immersed in 0.5 mL of a saturated tetrahydrofuran solution of Pt(NO3)2 for 12 hours to obtain the metal organic framework material for quick detection of acetylene.

[0078] Example 3

[0079] 47.5 μmol of zirconium nitrate pentahydrate, 19 μmol of an organic ligand of the structure shown in formula I, wherein R1, R2, R3 and R4 are methylthio groups, and 47.5 μmol of acetic acid are added to a glass tube; 3.8 mL of dimethyl sulfoxide is added to the glass tube, the glass tube is sealed with a hydrogen-oxygen flame, ultrasonically mixed for 60 minutes, and then placed in a 100°C oven for heating for 48 hours, then naturally cooled to room temperature, filtered to obtain crystals, and the crystals are washed three times with N,N-dimethylformamide and acetonitrile; then 5 mg of the above crystals are immersed in a saturated methanol solution of 3 mL of NiCl2 at 80°C for 36 hours to obtain the metal organic framework material for quick detection of acetylene.

[0080] Example 4

[0081] 38 μmol of zirconium acetate, 19 μmol of an organic ligand of the structure shown in formula I, wherein R1 and R4 are methylthio groups, R2 and R3 are F atoms, and 950 μmol of hydrochloric acid are added to a glass tube; 3.8 mL of dioxane is added to the glass tube, and the glass tube is sealed with a hydrogen-oxygen flame, and after being mixed evenly by ultrasonication for 60 minutes, it is placed in a 150°C oven and heated for 6 hours, and then naturally cooled to room temperature, and filtered to obtain crystals, and the crystals are washed three times with N,N-dimethylformamide and acetonitrile; then 5 mg of the above crystals are immersed in a saturated methanol solution of 5 mL of PdCl2 at 50°C for 24 hours to obtain the metal organic framework material for quick detection of acetylene.

[0082] Characterization example:

[0083] (1) The UiO-68-2SMe and Pt@UiO-68-2SMe prepared in Example 1 were subjected to X-ray powder diffraction test. The X-ray powder diffraction pattern is as follows: Figure 3 shown.

[0084] from Figure 3The results of the X-ray powder diffraction test show that the synthetic UiO-68-2SMe diffraction spectrum is highly consistent with the single crystal simulated X-ray powder diffraction in peak position, indicating that the synthesized UiO-68-2SMe is pure phase, and it can also be seen from the diffraction spectrum that the diffraction peak of UiO-68-2SMe is strong and sharp, indicating that the synthesized MOF has good crystallinity. In addition, the Pt@UiO-68-2SMe after Pt is fixed has the same diffraction as UiO-68-2SMe, indicating that the fixation of Pt does not affect the metal organic framework structure.

[0085] UiO-68-2SMe crystallizes in the cubic space group (Fm-3m, 225), where Specific lattice parameters are shown in Table 1:

[0086] Table 1 Crystal data of UiO-68-2SMe

[0087]

[0088]

[0089] a R1=∑(||F0|-|F c ||) / ∑|F0|; b wR2=(∑w(F0 2 -F c 2 ) 2 / ∑w(F0 2 ) 2 ) 1 / 2

[0090] UiO-68-2SMe uses Zr6O4(OH)4 clusters as SBUs, each of which is coordinated with 12 linkers, giving a three-dimensional network such as Figure 4 As shown; the network has an FCU topology consisting of tetrahedral and octahedral cages.

[0091] (2) The UiO-68-2SMe and Pt@UiO-68-2SMe prepared in Example 1 were subjected to infrared spectroscopy test. The infrared spectroscopy test diagram is shown in FIG. Figure 5 shown.

[0092] from Figure 5 The Fourier transform infrared (FT-IR) spectrum shows that the organic ligand is at 1685 cm -1 The infrared peak at 1601 cm belongs to C=O. When the carboxyl group of the organic ligand coordinates with the metal ion to form UiO-68-2SMe, the C=O peak red-shifts to 1601 cm -1 , which indicates that the organic ligands and metal ion clusters are successfully coordinated.

[0093] (3) The Pt@UiO-68-2SMe prepared in Example 1 was observed by scanning electron microscopy. The SEM image is shown in Figure 6, and the EDS image is shown in Figure 7.

[0094] Figure 6 The SEM image in the middle shows that Pt@UiO-68-2SMe is octahedral. Figure 7 The EDS element mapping images confirm the uniform distribution of C, O, Zr, S, and Pt elements.

[0095] (4) The UiO-68-2SMe and Pt@UiO-68-2SMe prepared in Example 1 were subjected to X-ray photoelectron spectroscopy (XPS) testing, and the XPS spectra of the S2p region thereof are shown in FIG8 ; the high-resolution Pt 4f XPS spectrum of Pt@UiO-68-2SMe is shown in FIG9 .

[0096] Figure 8 The XPS spectra of the S2p region of UiO-68-2SMe and Pt@UiO-68-2SMe show that the S 2p of the CSC bond of UiO-68-2SMe 3 / 2 and S 2p 1 / 2 The peaks at 163.39 and 164.57 eV shifted to 164.17 and 165.35 eV after Pt fixation. In addition, two new peaks at 161.90 and 162.80 eV are attributed to the S2p of Pt-S bonds. 3 / 2 and S2p 1 / 2 , the binding energy of S2p changes, which reveals the formation of Pt-S interaction. In addition, corresponding to Pt 4f 7 / 2 and Pt 4f 5 / 2 The peaks at 72.77 and 76.07 eV are only shown in the Pt@UiO-68-2SMe sample, as shown in Fig. 9 shown.

[0097] (5) Raman test was performed on UiO-68-2SMe and Pt@UiO-68-2SMe prepared in Example 1. The Raman spectra are shown in FIG. Fig.10 shown.

[0098] Fig.10 As can be seen in the figure, UiO-68-2SMe and Pt@UiO-68-2SMe were tested by Raman spectroscopy and found that the Raman spectroscopy at 360 and 336 cm –1 The SEM and XPS results show that the morphology and uniform distribution of Pt(II) are maintained in Pt@UiO-68-2SMe.

[0099] Test example:

[0100] (1) The UiO-68-2SMe crystal prepared in Example 1 was immersed in a 70°C C2H2 aqueous solution for 15 minutes; and the UiO-68-SMe crystal prepared in Example 1 was purged in C2H2 gas for 30 minutes. Under these two treatments, the color change of the UiO-68-SMe crystal was observed. The color of the UiO-68-2SMe crystal after treatment is as follows: Fig.11 The Raman spectrum of the UiO-68-2SMe crystals before and after treatment was tested, and the results were as follows Fig.12 As shown; the UiO-68-2SMe crystals before and after treatment were tested by infrared spectroscopy, and the results are as follows Fig.13 shown.

[0101] from Fig.11 It can be seen that when the UiO-68-2SMe crystals were immersed in a 70°C C2H2 aqueous solution for 15 min; or when the UiO-68-SMe crystals prepared in Example 1 were purged in C2H2 gas for 30 min, the color of the UiO-68-SMe crystals hardly changed. Fig.12 The Raman spectrum of polyacetylene does not show the characteristic peaks of polyacetylene. Fig.13 The infrared spectrum of UiO-68-2SMe did not change, indicating that UiO-68-2SMe could not achieve the catalytic polymerization of acetylene.

[0102] After the Pt@UiO-68-2SMe prepared in Example 1 was purged with pure gases acetylene (C2H2), ethane (C2H6), ethylene (C2H4), hydrogen (H2), nitrogen (N2), and carbon dioxide (CO2) for 2 hours, the color change of the Pt@UiO-68-SMe crystal was observed. The results are as follows: Fig.14 As shown; pure C2H2 was used to purge Pt@UiO-68-2SMe crystals for 30 minutes, and the color changed as shown Fig.15 As shown; Raman spectrum as Fig.16 shown.

[0103] from Fig.14 It can be seen that the color of Pt@UiO-68-2SMe crystals turns black only after being purged with C2H2 gas, and there is no obvious change in the color of Pt@UiO-68-2SMe purged with other gases. Fig.15 It can be seen that the color of Pt@UiO-68-2SMe crystals gradually deepened during the 30 min of acetylene purging; Fig.16 The Raman spectrum test found that as time goes by, the Raman characteristic peak of polyacetylene gradually increases, indicating that the polyacetylene content in the crystal gradually increases. Therefore, the Pt@UiO-68-2SMe crystal of the present invention can achieve rapid catalytic polymerization of acetylene gas, and the change in the color of the Pt@UiO-68-2SMe crystal caused by polyacetylene can be used to achieve visible detection.

[0104] (2) Pt@UiO-68-2SMe crystals were immersed in transformer oil containing various gases (C2H2, N2, C2H4, C2H6, H2, CO, CO2), heated at 70°C for 15 min, and the color change of Pt@UiO-68-2SMe was observed. The results are as follows: Fig.17 shown.

[0105] from Fig.17 It can be seen that in transformer oil with dissolved C2H2, the color of Pt@UiO-68-2SMe crystals changes from light yellow to obvious brown-red, while in transformer oil with other gases, there is no color change of Pt@UiO-68-2SMe crystals. Therefore, the color of Pt@UiO-68-2SMe crystals can respond quickly and selectively to C2H2, making it a reliable colorimetric sensor for rapid detection of C2H2 in a wide range of scenarios.

[0106] The Pt@UiO-68-2SMe crystals were immersed in transformer oil with different C2H2 concentrations (4.1ppm, 8.2ppm, 10.3ppm, 820ppm), heated at 70℃ for 15min, and the color change of Pt@UiO-68-2SMe was observed; and the Pt@UiO-68-2SMe crystals were immersed in C2H2 transformer oil with a concentration of 820ppm for 3h, and the color change of Pt@UiO-68-2SMe was observed. The results are as follows Fig.18 shown.

[0107] from Fig.18 It can be seen that the higher the C2H2 concentration, the darker the color of the immersed Pt@UiO-68-2SMe crystals; when the Pt@UiO-68-2SMe crystals are immersed in transformer oil with only 4.1ppm C2H2 for 15min, the color change can still be easily identified by the naked eye, showing excellent colorimetric detection performance. 4.1ppm is also the current detection limit (LOD) of C2H2 colorimetric detection using Pt@UiO-68-2SMe crystals. This LOD is within the concentration range of 2 to 9ppm of C2H2 released in transformer oil, so it is of practical value for monitoring the operating conditions of transformers in actual operation. When the immersion time is 3h, the Pt@UiO-68-2SMe crystals turn black, which indicates the continuous catalytic performance of Pt@UiO-68-2SMe. Therefore, the Pt@UiO-68-2SMe crystal is a stable colorimetric sensor that can be used to quickly determine C2H2 dissolved in transformer oil with high sensitivity and selectivity.

[0108] In summary, the present application uses a dicarboxylic acid with a flexible thiomethyl group and a group IB metal ion precursor to construct an original MOF by a solvothermal method, and uses the soft functional group thiomethyl on the side chain of the MOF to fix the group VIII metal ions to obtain a post-synthesized MOF, which can quickly and sensitively adsorb and catalyze acetylene polymerization. The formed polymer causes a specific change in the color of the post-synthesized MOF, which can be used as an excellent colorimetric sensor. In particular, it reacts in transformer oil with extremely low C2H2 content and is accompanied by obvious color changes visible to the naked eye, realizing rapid monitoring of the transformer operating status, overcoming the problems of traditional detection methods that are time-consuming, costly, and demanding on instruments.

[0109] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A metal organic framework material for quick detection of acetylene, characterized in that: It comprises a metal organic framework composed of an organic ligand of a structure shown in formula I and a group IB metal ion, and a group VIII metal ion fixed in the metal organic framework; the group VIII metal ion is connected by coordination with a methylthio group in the organic ligand of a structure shown in formula I and fixed in the metal organic framework; wherein R1, R2, R3, and R4 are H, C1-C3 alkyl, halogen, or methylthio, and at least one of R1, R2, R3, and R4 is methylthio; In the metal-organic framework composed of the organic ligand of the structure shown in formula I and the group IB metal ion, the group IB metal ion is coordinated with the carboxyl group of the organic ligand of the structure shown in formula I in the form of M6O4(OH)4 clusters to form an fcu topological structure composed of tetrahedral and octahedral cages, wherein M is a group IB metal ion; The IB group metal ion is a zirconium ion; the VIII group metal ion is a platinum ion; The metal organic framework material for quick detection of acetylene is prepared by adding an organic ligand having a structure shown in formula I, a group IB metal ion precursor and a regulator to a first solvent for dissolution; then performing a solvothermal reaction under closed conditions, and after the reaction is completed, performing solid-liquid separation to obtain a solid product, and then adding the solid product to a second solvent in which a group VIII metal ion precursor is dissolved for reaction; The regulator is benzoic acid; the molar ratio of the IB group metal ion precursor to the regulator is 1:(1-50).

2. The method for preparing a metal organic framework material for quick detection of acetylene according to claim 1, characterized in that: The following steps are involved: An organic ligand having a structure shown in formula I, a group IB metal ion precursor and a regulator are added to a first solvent for dissolution; a solvent thermal reaction is then carried out under closed conditions. After the reaction is completed, solid-liquid separation is performed to obtain a solid product, and the solid product is then added to a second solvent in which a group VIII metal ion precursor is dissolved for reaction to obtain the metal organic framework material for quick detection of acetylene.

3. The method for preparing a metal organic framework material for quick detection of acetylene according to claim 2, characterized in that: The IB group metal ion precursor is one or a combination of two or more of chlorides, nitrates, acetates and hydrates of the IB group metal ions; the molar ratio of the organic ligand with the structure shown in formula I to the IB group metal ion precursor is 1:(1.5-2.5).

4. The method for preparing a metal organic framework material for quick detection of acetylene according to claim 2, characterized in that: The first solvent is one or a combination of two or more selected from N,N-dimethylformamide, N,N-diethylformamide, dioxane, and dimethyl sulfoxide; the second solvent is one or a combination of two or more selected from acetonitrile, methanol, tetrahydrofuran, N,N-dimethylformamide, and N,N-diethylformamide; the molar volume ratio of the organic ligand of the structure shown in Formula I to the first solvent is 1 mmol:(10-200) ml.

5. The method for preparing a metal organic framework material for quick detection of acetylene according to claim 2, characterized in that: The Group VIII metal ion precursor is one or a combination of two or more of chlorides, nitrates, acetates and hydrates of Group VIII metal ions; The solid product is added to a second solvent in which a Group VIII metal ion precursor is dissolved to react, wherein the mass volume ratio of the solid product to the second solvent in which the Group VIII metal ion precursor is dissolved is 1 mg:(0.1-1) mL; and the concentration of the Group VIII metal ion precursor in the second solvent in which the Group VIII metal ion precursor is dissolved is 0.01-0.1 mmol / mL.

6. The method for preparing a metal organic framework material for quick detection of acetylene according to claim 2, characterized in that: The conditions for the solvothermal reaction are 90-150° C. for 6-96 hours; the conditions for the solid product and the Group VIII metal ion precursor dissolved in the second solvent for reaction are 10-80° C. for 12-96 hours.

7. Use of the metal organic framework material for quick detection of acetylene as claimed in claim 1 in detecting dissolved acetylene in transformer oil.

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