1,3-Dimethylpyrazole Compound Containing Cu(II), Preparation Method and Application
The 1,3-dimethylpyrazole compound containing Cu(II) was synthesized by solution volatilization. As urease and nitration inhibitors, the problems of low utilization rate of nitrogen fertilizer and environmental pollution were solved, and efficient utilization of nitrogen fertilizer and low-cost environmentally friendly preparation were achieved.
Patent Information
- Application Number
- CN202510386153.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2025-07-04
- Estimated Expiration
- 2045-03-31
AI Technical Summary
In the prior art, nitrogen fertilizer utilization is low, nitrogen loss is severe, resulting in environmental pollution, and the addition of urease and nitration inhibitors increases the cost of fertilizer production.
The 1,3-dimethylpyrazole compound containing Cu(II) was synthesized by solution volatilization method. It was used as a bifunctional inhibitor to inhibit urease and nitrifying bacteria. The preparation method was simple, and anhydrous methanol and dichloromethane were used as solvents.
Effectively extend the fertilizer efficiency of nitrogen fertilizer, improve the utilization rate of nitrogen fertilizer, reduce environmental pollution, reduce production costs, and there is no secondary pollution in the preparation process.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of fertilizer synergists, and particularly provides a Cu(II)-containing 1,3-dimethylpyrazole compound, a preparation method thereof and an application thereof. Background Art
[0002] 1,3-Dimethylpyrazole is a derivative of pyrazole and has significant nitrification inhibitory activity. In addition, transition metals exhibit important biological activities in many biochemical processes. Common transition metals include copper, nickel, cobalt, zinc, etc. At the same time, complexes formed with various metal ions have been proven to have significant inhibitory activities on various enzymes, and copper ions have been proven to have good urease inhibitory ability.
[0003] With the growth of the population, in order to meet the increasing demand for food, excessive amounts of nitrogen fertilizers are applied to farmland, and almost 50% of the nitrogen input is lost to the atmosphere or infiltrates into groundwater. Ammonia (NH3) volatilization is considered to be one of the main gaseous nitrogen loss processes. NH3 is not only a key gas involved in the formation of particulate matter (PM2.5), but also a secondary source of indirect nitrous oxide (N2O) emissions, and it also participates in the acidification and eutrophication of ecosystems through dry and wet deposition in the atmosphere, causing extremely serious ecological damage.
[0004] Therefore, it is crucial to develop a urease and nitrification inhibitor. Metal copper itself has an inhibitory effect on urease, and among them, the Cu(II)-containing coordination compound has a good effect on urease inhibition. The active site of urease is characterized by the presence of a helical flap at its entrance, which is considered to regulate the access of the substrate to the enzyme active site. Among them, copper ions can not only irreversibly occupy the binding site that should originally belong to nickel, causing irreversible inhibition of urease activity, but also block urea from entering its active site. By adding a copper complex to urea, the conversion of nitrogen fertilizer to ammonium nitrogen can be slowed down, and the retention time of urea in the soil can be extended. In order to inhibit the conversion of nitrogen fertilizer for a longer time and improve the utilization efficiency, in production practice, the method of adding a urease inhibitor and a nitrification inhibitor simultaneously is adopted to inhibit the process of urea hydrolysis into ammonium nitrogen and the process of ammonium nitrogen oxidation into nitrate nitrogen. However, the addition of the two inhibitors increases the production cost of fertilizers and is not conducive to popularization and application.
[0005] Based on the above background, the present invention selects to modify 1,3-dimethylpyrazole. Using 1,3-dimethylpyrazole as a ligand, a novel Cu(II)-containing 1,3-dimethylpyrazole compound is prepared by the solvent evaporation method. It can simultaneously inhibit urease and nitrifying bacteria and is a bifunctional inhibitor, which provides a new research direction for the green and healthy development of agriculture. Summary of the Invention
[0006] To solve the above technical problems, the present invention provides a Cu(II)-containing 1,3-dimethylpyrazole compound, a preparation method thereof, and an application thereof. Using 1,3-dimethylpyrazole as an organic ligand and Cu as a coordination center metal ion, a Cu(II)-containing 1,3-dimethylpyrazole compound is synthesized by a solution evaporation method in a certain proportion.
[0007] The present invention is implemented as follows. A preparation method of a Cu(II)-containing 1,3-dimethylpyrazole compound is provided, which includes the following steps: placing CuCl2·2H2O and 1,3-dimethylpyrazole in a container, adding anhydrous methanol and dichloromethane for dissolution; then sealing and puncturing the container, and standing at room temperature for 2-4 days to obtain black block crystals, which are washed, filtered, and dried to obtain the Cu(II)-containing 1,3-dimethylpyrazole compound.
[0008] Preferably, in terms of molar ratio, CuCl2·2H2O:1,3-dimethylpyrazole = 1:1.
[0009] Preferably, in terms of volume ratio, dichloromethane:anhydrous methanol = 1:2.
[0010] A Cu(II)-containing 1,3-dimethylpyrazole compound is provided, which is prepared according to the above preparation method of the Cu(II)-containing 1,3-dimethylpyrazole compound.
[0011] Preferably, the crystal form of the Cu(II)-containing 1,3-dimethylpyrazole compound belongs to the monoclinic system, and the space group is C2 / c.
[0012] Preferably, in the Cu(II)-containing 1,3-dimethylpyrazole compound, the coordination mode of the central ion copper(II) is a four-coordination structure. In a symmetry unit, the central ion copper(II) connects the nitrogen atoms in two identical 1,3-dimethylpyrazoles and two chlorine ions to form a symmetric square pyramid configuration. The bond length of Cu-Cl is 2.263 Å, the bond length of Cu-N is 1.975 Å, the bond angle of Cl-Cu-Cl is 177.05°, and the bond angle of N-Cu-N is 178.5°.
[0013] An application of the Cu(II)-containing 1,3-dimethylpyrazole compound is provided, which is used as a urease and nitrification inhibitor in fertilizers.
[0014] Preferably, in the above application, the fertilizer is a nitrogen fertilizer.
[0015] Preferably, in the above application, the fertilizer is urea.
[0016] Compared with the prior art, the advantages of the present invention are as follows:
[0017] The prepared Cu(II)-containing 1,3-dimethylpyrazole compound of the present invention has good inhibitory effects on soil urease and nitrifying bacteria, can effectively delay the conversion of urea nitrogen to ammonium nitrogen, and at the same time delay the conversion of ammonium nitrogen to nitrate nitrogen, so that nitrogen can be retained in the soil in a form that is more easily utilized by crops for a longer time, and can effectively extend the fertilizer efficiency period of nitrogen fertilizer. And this preparation method is simple, the solvents used are only anhydrous methanol and dichloromethane, the preparation process does not consume energy and does not produce secondary pollution, and has good application prospects. The Cu(II)-containing 1,3-dimethylpyrazole compound prepared by the present invention is a dual-functional inhibitor, with advantages such as high inhibition rate, low dosage, good stability, not easily leached by water, low toxicity, and small environmental impact, and can be used as a new type of fertilizer additive. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention will be further described in detail below in conjunction with the drawings and embodiments:
[0019] Figure 1 It is the single crystal thermal ellipsoid diagram of the target product prepared in Example 1.
[0020] Figure 2 It is the comparison between the powder X-ray diffraction pattern of the target product prepared in Example 1 and the simulated diagram of single crystal data.
[0021] Figure 3 It is the inhibition diagram of the target product prepared in Example 1 with different concentrations on urease. SPECIFIC EMBODIMENTS
[0022] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0023] Example 1
[0024] (I) Preparation method
[0025] Put 0.034 g (0.2 mmol) of CuCl2·2H2O and 0.0182 g (0.2 mmol) of 1,3-dimethylpyrazole into a 50 ml conical flask respectively, add 6 mL of anhydrous methanol and 3 mL of dichloromethane to completely dissolve them; after sealing and puncturing holes, let it stand at room temperature for about 3 days to obtain black blocky crystals. Wash, filter and dry the blocky crystals to obtain the Cu(II)-containing 1,3-dimethylpyrazole compound, and the yield is 95%.
[0026] (II) Detection
[0027] The diffraction intensity data of single crystals were collected using graphite-monochromated Mo Kα (λ = 0.71073 Å) radiation as the diffraction light source on a Bruker D8 X-ray diffractometer. The prepared 1,3-dimethylpyrazole compound containing Cu(II) was taken, and the data obtained by SC-XRD were further used to obtain its structural diagram as shown in Figure 1 . Its crystal form belongs to the monoclinic system, and the space group is C2 / c. In an independent unit, the central ion copper(II) has a tetrahedral geometry and coordinates with two nitrogen atoms of two 1,3-dimethylpyrazole ligand donor atoms. The central ion Cu(II) connects the nitrogen atoms in two identical 1,3-dimethylpyrazoles and two chloride ions to form a symmetric square pyramid configuration. The bond length of Cu-Cl is 2.263 Å, the bond length of Cu-N is 1.975 Å, the bond angle of Cl-Cu-Cl is 177.05°, and the bond angle of N-Cu-N is 178.5°. The crystallographic parameters are shown in Table 1.
[0028] The powder diffraction experiment of the crystal was carried out using a Bruker D8 Advance X-ray powder diffractometer. Graphite-monochromated CuKα radiation with a wavelength of λ = 1.54056 Å, a solid detector, a step size of 0.01°, a step time of 0.3 s, and a scanning range of 5° ≤ 2θ ≤ 45° were used. The powder X-ray diffraction pattern of the prepared 1,3-dimethylpyrazole compound containing Cu(II) matched the simulated pattern of the single crystal data ( Figure 2 ).
[0029] Table 1
[0030]
[0031] Example 2
[0032] 0.034 g (0.2 mmol) of CuCl2·2H2O and 0.0182 g (0.2 mmol) of 1,3-dimethylpyrazole were respectively placed in a 50 ml conical flask, and 6 mL of anhydrous methanol and 3 mL of dichloromethane were added to completely dissolve them. After sealing and puncturing the holes, it was left standing at room temperature for about 5 days to obtain black blocky crystals. The blocky crystals were washed, filtered, and dried to obtain a 1,3-dimethylpyrazole compound containing Cu(II) with a yield of 93.7%.
[0033] Example 3
[0034] 0.034 g (0.2 mmol) of CuCl2·2H2O and 0.0182 g (0.2 mmol) of 1,3-dimethylpyrazole were separately placed into a 50 ml conical flask, and 12 mL of anhydrous methanol and 6 mL of dichloromethane were added to completely dissolve them; after sealing and puncturing holes, it was left standing at room temperature for about 4 days to obtain black blocky crystals. The blocky crystals were washed, filtered, and dried to obtain a 1,3-dimethylpyrazole compound containing Cu(II) with a yield of 91.3%.
[0035] Example 4
[0036] 0.034 g (0.2 mmol) of CuCl2·2H2O and 0.0182 g (0.2 mmol) of 1,3-dimethylpyrazole were separately placed into a 50 ml conical flask, and 4 mL of anhydrous methanol and 2 mL of dichloromethane were added to completely dissolve them; after sealing and puncturing holes, it was left standing at room temperature for about 3 days to obtain black blocky crystals. The blocky crystals were washed, filtered, and dried to obtain a 1,3-dimethylpyrazole compound containing Cu(II) with a yield of 85.6%.
[0037] Example 5
[0038] 0.034 g (0.2 mmol) of CuCl2·2H2O and 0.0182 g (0.2 mmol) of 1,3-dimethylpyrazole were separately placed into a 50 ml conical flask, and 6 mL of anhydrous methanol and 3 mL of dichloromethane were added to completely dissolve them; after sealing and puncturing holes, it was left standing at room temperature for about 2 days to obtain black blocky crystals. The blocky crystals were washed, filtered, and dried to obtain a 1,3-dimethylpyrazole compound containing Cu(II) with a yield of 68.1%.
[0039] Example 6
[0040] 0.034 g (0.2 mmol) of CuCl2·2H2O and 0.0182 g (0.2 mmol) of 1,3-dimethylpyrazole were separately placed into a 50 ml conical flask, and 10 mL of anhydrous methanol and 5 mL of dichloromethane were added to completely dissolve them; after sealing and puncturing holes, it was left standing at room temperature for about 4 days to obtain black blocky crystals. The blocky crystals were washed, filtered, and dried to obtain a 1,3-dimethylpyrazole compound containing Cu(II) with a yield of 77.4%.
[0041] Example 7
[0042] 1. The method for measuring the urease inhibitor activity is as follows:
[0043] The jack bean urease used in the test was commercially available. After grinding the sample to be tested into powder, a certain mass of the sample was weighed and dissolved and made up to volume with DMSO solution (DMSO:H2O = 1:1) to obtain sample solutions with different concentrations. Subsequently, 4 mL of urease solution (10 KU / L) and 4 mL of sample solutions with different concentrations were taken, mixed evenly, pre-cultured at 37 °C for 1 h, and then 32 mL of phosphate buffer solution with pH = 6.8 (containing 500 mM / L urea and 0.002% phenol red indicator) was added thereto. The pH range was 6.8 - 7.7, and the absorbance was measured at 570 nm with an ultraviolet spectrophotometer every 1 h. The end point of the test was determined by the phenol red indicator, and the test was stopped when the solution changed from light orange-yellow to purplish-red. The results are shown in Figure 3 .
[0044] IC 50 Calculation:
[0045] The modified Karber method was adopted: lgIC 50 = Xm - I(P - (3 - Pm - Pn) / 4), where Xm: lg maximum dose, I: lg(maximum dose / adjacent dose), P: sum of positive reaction rates, Pm: maximum positive reaction rate, Pn: minimum positive reaction rate. The calculated IC 50 = 0.68 ± 0.01 μM / L. It can be seen that when this Cu(II)-containing 1,3-dimethylpyrazole compound is used as a urease inhibitor, the half-inhibitory concentration is relatively low and the dosage of the additive is small. Therefore, it can be concluded that the Cu(II)-containing 1,3-dimethylpyrazole compound of the present invention can be used as a urease inhibitor in urea fertilizer.
[0046] The method for measuring the nitrification inhibition activity is as follows:
[0047] 0 g (control), 0.003 g, 0.005 g, 0.007 g, and 0.010 g of the Cu(II)-containing 1,3-dimethylpyrazole compound prepared in Example 1 were weighed respectively and placed in 500 mL conical flasks. 50.00 g of air-dried soil, 0.50 g of urea, and 100 mL of phosphate buffer solution were added to each flask. The conical flasks were simultaneously placed in a constant temperature culture oscillator (180 revolutions per minute) and oscillated for 48 h, then filtered, and the mass fractions ω1 of nitrate nitrogen (including nitrite nitrogen) in the sample solution and the control sample solution were measured respectively.
[0048] Calculation of the nitrification inhibition rate, and the nitrification inhibition rates of the dinuclear ligands with different addition amounts were calculated. The results are shown in Table 2.
[0049]
[0050] Among them, dN : Nitrification inhibition rate (%);
[0051] ω1—the mass fraction of nitrate nitrogen (including nitrite nitrogen) in the sample;
[0052] ω2—the mass fraction of nitrate nitrogen (including nitrite nitrogen) in the control sample, ω2 = 962.4.
[0053] Table 2
[0054]
[0055] As can be seen from Table 2, the 1,3-dimethylpyrazole compound containing Cu(II) can be used as a nitrification inhibitor, and its nitrification inhibition rate increases with the increase of the dosage. However, when the addition amount is greater than 0.003 g, the change in the nitrification inhibition rate reaches 10.14. Considering the cost factor, 3‰ is the optimal addition amount. To sum up, the present invention can be used as a dual-functional inhibitor of urease and nitrification in the fertilizer urea.
[0056] The above has made a detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.
Claims
1. A crystal of a Cu(II)-containing 1,3-dimethylpyrazole compound, characterized in that, The preparation method comprises the following steps: placing CuCl2·2H2O and 1,3-dimethylpyrazole in a container, adding anhydrous methanol and dichloromethane for dissolution; then sealing and puncturing the container, and standing at room temperature for 2 - 4 days to obtain black blocky crystals, which are washed, filtered and dried to obtain a 1,3-dimethylpyrazole compound containing Cu(II). The crystal form of the 1,3-dimethylpyrazole compound containing Cu(II) belongs to the monoclinic system, and the space group is C2 / c; In the 1,3-dimethylpyrazole compound containing Cu(II), the coordination mode of the central ion copper(II) is a four-coordination structure. In a symmetry unit, the central ion copper(II) connects the nitrogen atoms in two identical 1,3-dimethylpyrazoles and two chloride ions to form a symmetric square pyramid configuration. The bond length of Cu-Cl is 2.263 Å, the bond length of Cu-N is 1.975 Å, the bond angle of Cl-Cu-Cl is 177.05°, and the bond angle of N-Cu-N is 178.5°.
2. The crystal of the Cu(II)-containing 1,3-dimethylpyrazole compound according to claim 1, characterized in that, By molar ratio, CuCl2·2H2O:1,3-dimethylpyrazole = 1:
1.
3. The crystal of the Cu(II)-containing 1,3-dimethylpyrazole compound according to claim 1, characterized in that, By volume ratio, dichloromethane:anhydrous methanol = 1:
2.
4. Use of a crystal of a Cu(II)-containing 1,3-dimethylpyrazole compound according to claim 1, characterized in that, It is used as a urease and nitrification inhibitor in fertilizers.
5. Use of the crystal of the Cu(II)-containing 1,3-dimethylpyrazole compound according to claim 4, characterized in that, The fertilizer is a nitrogen fertilizer.
6. Use of the crystal of the Cu(II)-containing 1,3-dimethylpyrazole compound according to claim 5, characterized in that, The fertilizer is urea.