Bis (3-nitro-1, 2, 4-triazolyl) guanidine borate crystal and culture method thereof

Abstract

The invention provides a di (3-nitro-1, 2, 4-triazolyl) guanidine borate crystal and a culture method thereof, the crystal belongs to a triclinic system, the space group is P-1, the cell parameters a = 6.5572 (12), b = 7.7250 (14), c = 12.763 (2), alpha = 84.965 (3), beta = 80.876 (3), gamma = 88.150 (3), Z = 2, and the molecular weight is 299.05, and the cell parameters a = 6.5572 (12), b = 7.7250 (14), c = 12.763 (2), alpha = 84.965 (3), beta = 80.876 (3), gamma = 88.150 (3), Z = 2. According to the invention, a gradient cooling method is adopted, the single crystal is obtained by strictly controlling the solution temperature, the cooling rate, the heat preservation time and other operations, and the method is an effective way explored on the basis of failure of other methods. The (3-nitro-1, 2, 4-triazolyl) guanidine borate single crystal is cultured for the first time, the structure of the (3-nitro-1, 2, 4-triazolyl) guanidine borate single crystal is analyzed, the culture method is convenient and simple, and the purity of the cultured crystal is high.

Description

Technical Field

[0001] The invention relates to the technical field of energetic material synthesis, in particular to a di(3-nitro-1,2,4-triazolyl)guanidine borate crystal and a cultivation method thereof. Background Art

[0002] Guanidine di(3-nitro-1,2,4-triazolyl)borate is a new type of boron-based energetic ion salt and a potential solid propellant fuel. Research on boron-based energetic compounds is still in its infancy in China. Compared with other types of compounds, the synthesis conditions of ionic boron-based energetic compounds are relatively simple and the performance is easy to control. The performance can be optimized by introducing different azole energetic groups on the B atom, and then by matching different energetic cations, boron-based energetic ion salts with special properties can be formed. At present, there have been reports on the synthesis method of boron-based energetic ion salts abroad, and guanidine di(3-nitro-1,2,4-triazolyl)borate is one of them, and the molecular formula is shown in the figure below.

[0003]

[0004] However, the report did not successfully cultivate single crystals. By consulting other documents, no reports on the preparation of di(3-nitro-1,2,4-triazolyl)guanidine borate single crystals and crystal analysis have been found. The present invention cultivates di(3-nitro-1,2,4-triazolyl)guanidine borate single crystals by recrystallization and gradient cooling method, and realizes the separation of di(3-nitro-1,2,4-triazolyl)guanidine borate from other impurities. Summary of the invention

[0005] The invention aims to provide a di(3-nitro-1,2,4-triazolyl)guanidine borate single crystal and a cultivation method thereof, and the absolute configuration of the di(3-nitro-1,2,4-triazolyl)guanidine borate molecule can be determined through the single crystal.

[0006] In the first aspect, the present invention provides a di(3-nitro-1,2,4-triazolyl)guanidine borate crystal, the name of the crystal compound is: di(3-nitro-1,2,4-triazolyl)guanidine borate, the molecular formula is C 5 H 10 BN 11 O, chemical structure formula:

[0007]

[0008] The crystal belongs to the triclinic system, the space group is P-1, and the unit cell parameters are α=84.965(3)°, β=80.876(3)°, γ=88.150(3)°, Z=2, molecular weight is 299.05;

[0009] It appears as light yellow block crystals at room temperature.

[0010] In a second aspect, the present invention further provides a method for culturing di(3-nitro-1,2,4-triazolyl)guanidine borate crystals, which uses a gradient cooling method to culture single crystals, and specifically comprises the following steps:

[0011] (1) preparing a di(3-nitro-1,2,4-triazolyl)guanidine borate solution at 70° C. to 75° C.;

[0012] (2) placing the above solution in an incubator, setting the temperature in the incubator to 70° C., and stabilizing at this temperature for 0.5 to 2 hours before gradually cooling down: in the first stage, the temperature of the solution is lowered to 60° C. at a first cooling rate and kept warm for 30 minutes; in the second stage, the temperature is lowered from 60° C. to 50° C. at a second cooling rate and kept warm for 30 minutes; in the third stage, the temperature is lowered from 50° C. to 40° C. at a third cooling rate and kept warm for 30 minutes; in the fourth stage, the temperature is lowered from 40° C. to room temperature at a fourth cooling rate, and when the temperature of the solution is in the range of 38° C. to 36° C., crystals begin to precipitate;

[0013] (3) After the solution temperature drops to room temperature, the solution is left to stand for 24 to 48 hours to obtain a single crystal of di(3-nitro-1,2,4-triazolyl)guanidine borate.

[0014] Preferably, the concentration of the di(3-nitro-1,2,4-triazolyl)guanidine borate solution is 0.5-1 mol / L.

[0015] Preferably, the first cooling rate is 1°C / 30min.

[0016] Preferably, the second cooling rate is 1°C / 30min.

[0017] Preferably, the third cooling rate is 1°C / 10min to 1°C / 30min.

[0018] Preferably, the fourth cooling rate is 1°C / 10min to 1°C / 30min.

[0019] Compared with the prior art, the present invention adopts a gradient cooling method and uses supersaturation to control the crystallization process. After strictly controlling the solution temperature, cooling rate and holding time, single crystals can be successfully obtained. This method is an effective method explored on the basis of the failure of natural cooling, solvent evaporation and other methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a molecular structure diagram of di(3-nitro-1,2,4-triazolyl)guanidine borate crystals.

[0021] Figure 2This is the molecular stacking diagram of di(3-nitro-1,2,4-triazolyl)guanidine borate crystals.

[0022] Figure 3 This is the H NMR spectrum of bis(3-nitro-1,2,4-triazolyl)guanidine borate crystals.

[0023] Figure 4 It is a crystalline di(3-nitro-1,2,4-triazolyl)guanidine borate 13 C NMR spectroscopy.

[0024] Figure 5 This is the infrared spectrum of di(3-nitro-1,2,4-triazolyl)guanidine borate crystals.

[0025] Figure 6 DSC (a) and TG-DTG (b) graphs of di(3-nitro-1,2,4-triazolyl)guanidine borate crystals.

[0026] Figure 7 This is the appearance of di(3-nitro-1,2,4-triazolyl)guanidine borate crystals. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0028] The present invention can determine the molecular structure information of di(3-nitro-1,2,4-triazolyl)guanidine borate and infer its physical and chemical properties through the crystal form study of the di(3-nitro-1,2,4-triazolyl)guanidine borate, so as to provide a certain theoretical basis for its application in the field of energetic materials.

[0029] At room temperature of 25°C, barium di(3-nitro-1,2,4-triazolyl)borate (1.09 g) was dissolved in 20 ml of distilled water and stirred until it dissolved quickly. Guanidine sulfate (0.648 g, 3 mmol) was added to the solution, and a white precipitate was immediately generated. After stirring for 10 minutes, the solution was filtered to obtain a transparent solution. After drying in an oven for 24 hours, a powdery white solid was obtained, i.e., crude di(3-nitro-1,2,4-triazolyl)borate guanidine.

[0030] Example 1

[0031] 1. Single crystal cultivation by cooling method

[0032] (1) Prepare a solution at 70°C to 75°C. Dissolve 0.6 g crude di(3-nitro-1,2,4-triazolyl)guanidine borate in 50 ml distilled water at 70°C to 75°C and stir until it dissolves quickly.

[0033] (2) Gradient cooling. Place the solution in an incubator and set the temperature in the incubator to 70°C. After stabilizing at this temperature for 2 hours, begin cooling. The cooling is divided into four stages: the first stage: lower the solution temperature to 60°C at a cooling rate of 1°C / 30min and keep warm for 30 minutes; the second stage: lower the temperature from 60°C to 50°C at a cooling rate of 1°C / 30min and keep warm for 30 minutes; the third stage: lower the temperature from 50°C to 40°C at a cooling rate of 1°C / 10min and keep warm for 30 minutes; the fourth stage: lower the temperature from 40°C to room temperature. When the filtrate temperature is in the range of 38°C to 36°C, crystals begin to precipitate in the beaker at a cooling rate of 1°C / 20min; (3) When the solution temperature in the beaker drops to room temperature and is placed for 24 to 48 hours, a light yellow single crystal of di(3-nitro-1,2,4-triazolyl)guanidine borate is obtained, which has an appearance as shown in the figure. Figure 7 shown.

[0034] 2. Single Crystal Structure Determination

[0035] A single crystal with a size of 0.26 mm × 0.25 mm × 0.24 mm was selected and scanned in ω mode on a Bruker D8 VENTURE diffractometer using GaKα (λ = 0.71073 nm) rays monochromatized by a graphite monochromator. The scanning range was 6.294°≤2θ≤49.988°, -7≤h≤7, -9≤k≤8, -12≤l≤15. A total of 3250 diffraction points were collected at 296.15 K, of which 2212 were independent diffraction points (R int =0.0192). Olex2 software was used for structural analysis, and the SHELXL software package was used for single crystal structure refinement using the least squares method. The analysis results showed that it belongs to the triclinic system, the space group is P-1, and the unit cell parameters are α=84.965(3)°, β=80.876(3)°, γ=88.150(3)°, Z=2, and the calculated molecular weight is 299.05.

[0036] The specific parameters are shown in Table 1.

[0037] Table 1 Partial crystal data of compounds

[0038]

[0039]

[0040] Crystalline molecular structure Figure 1 The unit cell stacking diagram is shown in Figure 2 The bond lengths and bond angles are listed in Table 2 and Table 3 respectively.

[0041] Table 2 Some bond lengths

[0042]

[0043] Table 3 Some bond angles

[0044]

[0045]

[0046] Symmetry code:#1-x+1,-y,-z#2-x+2,y-1 / 2,-z+1 / 2,#3-x+2,y+1 / 2,-z+1 / 2#4-x+2,-y,-z

[0047] 3. NMR spectra

[0048] Hydrogen spectrum Figure 3 As shown, the hydrogen on the triazole ring is a single peak at 8.50 ppm; the peak of BH is at 3.70 ppm, which coincides with the water peak in the solvent to form a broad peak; the hydrogen on the aminoguanidine is at 8.11 ppm and 6.99 ppm respectively.

[0049] Carbon spectrum Figure 4 As shown, there are three carbon atoms in the compound, with the carbon atoms on the triazole ring at 164.57 ppm and 150.58 ppm, respectively, and the carbon atom of aminoguanidine at 159.36 ppm.

[0050] 4. Infrared spectrum

[0051] Infrared Figure 5 As shown, the typical characteristic peaks are marked, 3199cm -1 、3353cm -1 and 3463cm -1 The characteristic peaks appearing at are mainly derived from NH and NH 2 The weak shoulder on the left side of 3199 is related to the triazole ring; 1390cm -1 Typical absorption peak of BN bond at 1303cm -1 and 1499cm -1 Nearby nitro absorption peak; 2478cm -1 and 2453cm -1 Nearby BH and BH 2 Extension vibration, etc.; 1550cm -1 and 1669cm -1 NH / C=N stretching vibration at 1669cm -1 The absorption peak mainly comes from the C=N stretching vibration in the guanidine group; in addition, the absorption peak related to the NH bond vibration is sharper, indicating that the guanidine salt is successfully bonded to the boron nitrogen compound.

[0052] 5. Differential thermal analysis

[0053] Differential thermal analysis curve Figure 6 As shown, the TG curve shows that the compound presents two weight loss stages. The first weight loss stage is not obvious, but it can be assisted by the DTA curve. This stage is in the range of 50-150℃, which is speculated to correspond to the volatilization of water. However, from the perspective of the single crystal structure, the molecule does not contain crystal water, so it is speculated that the sample may not be dry enough. The second weight loss stage is in the range of 205-285℃, corresponding to the self-decomposition reaction of the compound. In the DSC curve, there are two exothermic peaks, of which the main exothermic peak is at 250℃.

Claims

1. A di(3-nitro-1,2,4-triazolyl)guanidine borate crystal, characterized in that: The crystal chemical name is: di(3-nitro-1,2,4-triazolyl)guanidine borate, and the molecular formula is C5H 10 BN 11 O, chemical structure formula is:

2. The crystal according to claim 1, characterized in that The crystal belongs to the triclinic system, the space group is P-1, and the unit cell parameters are α=84.965(3)°, β=80.876(3)°, γ=88.150(3)°, Z=2, molecular weight is 299.05; It appears as light yellow block crystals at room temperature.

3. The method for growing a crystal according to claim 1 or 2, wherein: The single crystal culture is carried out by using a gradient cooling method, which specifically includes the following steps: (1) preparing a di(3-nitro-1,2,4-triazolyl)guanidine borate solution at 70° C. to 75° C.; (2) placing the above solution in an incubator, setting the temperature in the incubator to 70° C., and stabilizing at this temperature for 0.5 to 2 hours before gradually cooling down: in the first stage, the temperature of the solution is lowered to 60° C. at a first cooling rate and kept warm for 30 minutes; in the second stage, the temperature is lowered from 60° C. to 50° C. at a second cooling rate and kept warm for 30 minutes; in the third stage, the temperature is lowered from 50° C. to 40° C. at a third cooling rate and kept warm for 30 minutes; in the fourth stage, the temperature is lowered from 40° C. to room temperature at a fourth cooling rate, and when the temperature of the solution is in the range of 38° C. to 36° C., crystals begin to precipitate; (3) After the solution temperature drops to room temperature, the solution is left to stand for 24 to 48 hours to obtain a single crystal of di(3-nitro-1,2,4-triazolyl)guanidine borate.

4. The method according to claim 3, characterized in that The concentration of the di(3-nitro-1,2,4-triazolyl)guanidine borate solution is 0.5-1 mol / L.

5. The method according to claim 3, characterized in that The first cooling rate was 1°C / 30min.

6. The method according to claim 3, characterized in that The second cooling rate was 1°C / 30min.

7. The method according to claim 3, characterized in that The third cooling rate is 1°C / 10min to 1°C / 30min.

8. The method according to claim 3, characterized in that The fourth cooling rate is 1°C / 10min to 1°C / 30min.

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