Method for detecting (2-alkyl ammonia / hydrazino) ethyl hydrazine nitrate in propellant

Abstract

The invention provides a method for detecting a functional aid (2-alkyl ammonia / hydrazino) ethyl hydrazine nitrate in a propellant, and particularly provides a method for detecting the content of the functional aid (2-alkyl ammonia / hydrazino) ethyl hydrazine nitrate in a hydroxylamine nitrate green propellant by a liquid chromatography internal standard method. The separation conditions of the liquid chromatography are as follows: a chromatographic column stationary phase filler is a polar functional group terminated C18 column, the column length is 10-30cm, the inner diameter is 2.1-4.6 mm, the filler particle size is 3-10mu m, a differential refraction detector is adopted as a detector, the temperature of the detector is 30-50 DEG C, the column temperature is 20-40 DEG C, mobile phases comprise A (a monopotassium phosphate aqueous solution) and B (100% methanol or acetonitrile), the flow rate is 0.2-1.5 mL / min, isocratic elution is adopted, and the sample size is 2-10mu l. The detection method is simple and rapid to operate, accurate in determination and high in precision.

Description

Technical Field

[0001] This invention relates to a method for detecting the content of ethyl hydrazine nitrate (2-alkylamine / hydrazine) in hydroxylamine-based green propellants, belonging to the field of liquid propellant analysis. Background Technology

[0002] Liquid propellants are one of the key core technologies in the aerospace field and are the power source for rocket engines. Currently, the most widely used single-component liquid propellants are still anhydrous hydrazine and SHP-3. With the continuous development of aerospace technology and the increasing demands for environmental protection, the development of non-toxic, pollution-free, high-energy-density green liquid propellants to replace traditional hydrazine propellants has become a cutting-edge technology field that countries are vying to develop. For example, NASA mainly focuses on hydroxylamine nitrate (HAN) and ammonium dinitrate (ADN) green propellant technologies. After nearly 30 years of development, HAN propellant technology products mainly include AF-315E and SHP-163 (Acta Astronautica, 2022, 196, 194-214).

[0003] Domestically, the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences, the Shanghai Institute of Organic Chemistry, and the Beijing Aerospace Test Technology Research Institute are among the institutions conducting research on HAN propellant formulations and applications. Patent CN 117402024B discloses a HAN-based propellant invented by the Dalian Institute of Chemical Physics, composed of hydroxylamine nitrate (30-50% by mass), functional additive (2-alkylamino / hydrazyl)ethylhydrazine nitrate (10-20% by mass), fuel (15-30% by mass), and water (15-30% by mass). The functional additive (2-alkylamino / hydrazyl)ethylhydrazine nitrate is 2-aminoethylhydrazine nitrate, 2-methylaminoethylhydrazine nitrate, 2-dimethylaminoethylhydrazine nitrate, 2-hydrazylethylhydrazine nitrate, 2-ethylaminoethylhydrazine nitrate, and 2-diethylaminoethylhydrazine nitrate. This propellant allows for rapid ignition and is particularly suitable for the propulsion systems of rockets, spacecraft, and satellites.

[0004] The stability of propellant formulations significantly impacts their application performance, energy output, and combustion temperature. Therefore, establishing analytical methods for the content of components such as hydroxylamine nitrate, functional additives, and fuel in propellant systems is crucial for propellant stability control during formulation design and development, and is also of great significance for research into green and novel propellants. However, current reports lack methods for detecting ethylhydrazine nitrate, a functional additive (2-alkylamine / hydrazyl) in HAN-based propellants. Therefore, there is an urgent need to develop a simple, rapid, accurate, and highly precise method for its determination. Summary of the Invention

[0005] To address the existing technical problems, this application provides a quick, simple, and accurate method for detecting the functional additive (2-alkylamine / hydrazino) ethylhydrazine nitrate in hydroxylamine-based green propellants. This method also solves the problem of inaccurate determination of the content of the functional additive (2-alkylamine / hydrazino) ethylhydrazine nitrate caused by the difficulty in accurately controlling the injection volume in the external standard method.

[0006] This invention provides a method for determining (2-alkylamino / hydrazino)ethylhydrazine nitrate, a functional additive in propellants. The structural formula of (2-alkylamino / hydrazino)ethylhydrazine nitrate is as follows:

[0007]

[0008] R1 is one of hydrogen, methyl or amino, and R2 is one of hydrogen, methyl, ethyl, n-propyl or n-butyl.

[0009] Preferably, it is one of 2-aminoethylhydrazine nitrate, 2-methylaminoethylhydrazine nitrate, 2-dimethylaminoethylhydrazine nitrate, 2-hydrazylethylhydrazine nitrate, 2-ethylaminoethylhydrazine nitrate, and 2-diethylaminoethylhydrazine nitrate.

[0010] A method for detecting (2-alkylamino / hydrazino)ethylhydrazine nitrate in propellants, the method comprising the following steps:

[0011] (1) Using α-aminocaprolactam as an internal standard, the standard and the sample to be tested were dissolved and diluted with methanol to obtain the standard solution and the sample solution, respectively.

[0012] (2) The standard solution and sample solution obtained in step (1) were subjected to liquid chromatography analysis. A C18 column with polar functional group-capped stationary phase was used. The column length was 10-30 cm, the inner diameter was 2.1-4.6 mm, and the particle size of the packing material was 3-10 μm. A differential refractive index detector was used. The detector temperature was 30-50 °C, and the column temperature was 20-40 °C. The mobile phase consisted of A (potassium dihydrogen phosphate aqueous solution) and B (100% methanol or acetonitrile). The flow rate was 0.2-1.5 mL / min, and isocratic elution was used. The injection volume was 2-10 μL. The content of functional adjuvant (2-alkylamino / hydrazino) ethylhydrazine nitrate in the sample was calculated based on the peak area of ​​the functional adjuvant (2-alkylamino / hydrazino) ethylhydrazine nitrate in the standard solution and sample solution.

[0013] Furthermore, in the method for detecting the functional additive (2-alkylamino / hydrazine) ethylhydrazine nitrate, the column temperature in step (2) is preferably 25-35℃, more preferably 30℃; the column flow rate is preferably 0.8-1.2 mL / min, more preferably 1.0 mL / min; and the injection volume is preferably 3-7 μL, more preferably 5 μL.

[0014] Furthermore, in the method for detecting the functional additive (2-alkylamine / hydrazine) ethylhydrazine nitrate, the chromatographic column used in step (2) is preferably the ACE Excel 5AQ column, with a more effective specification of 25cm column length, 4.6mm inner diameter, and 5um packing particle size.

[0015] Furthermore, in the method for detecting the functional additive (2-alkylamine / hydrazine) ethylhydrazine nitrate, in step (2), the concentration of potassium dihydrogen phosphate in mobile phase A is 10-50 mmol, and mobile phase B is 100% acetonitrile.

[0016] Furthermore, in the method for detecting the functional additive (2-alkylamino / hydrazine) ethylhydrazine nitrate, step (2) involves moderate elution, with the volume content of mobile phase A ranging from 50% to 90%, preferably 60% to 80%, more preferably 65% ​​to 75%, and the volume content of mobile phase B ranging from 10% to 50%, preferably 20% to 40%, more preferably 25% to 35%.

[0017] Furthermore, in the method for detecting the functional additive (2-alkylamine / hydrazine) ethylhydrazine nitrate, the differential detector temperature in step (2) is 35°C.

[0018] Furthermore, in the method for detecting the functional additive (2-alkylamino / hydrazyl) ethylhydrazine nitrate, step (2) involves calculating the content of the functional additive (2-alkylamino / hydrazyl) ethylhydrazine nitrate in the sample to be tested according to the following formula:

[0019]

[0020] In the formula:

[0021] f—relative calibration factor;

[0022] m n —The mass of functional adjuvant (2-alkylamino / hydrazino) ethylhydrazine nitrate in the standard solution;

[0023] A n —Peak area of ​​functional adjuvant (2-alkylamino / hydrazino) ethylhydrazine nitrate in standard solution;

[0024] A s —Peak area of ​​the internal standard in the standard solution;

[0025] m s —The mass of the internal standard in the standard solution;

[0026] W i —The mass percentage of functional additive (2-alkylamino / hydrazino) ethylhydrazine nitrate in the sample to be tested;

[0027] A i—Peak area of ​​functional additive (2-alkylamino / hydrazino) ethylhydrazine nitrate in the sample solution;

[0028] A1—Peak area of ​​the internal standard in the sample solution;

[0029] m1 — the mass of the internal standard in the sample solution;

[0030] m i —Weigh the mass of the non-toxic propellant sample to be tested.

[0031] The detection method of this invention is simple and fast to operate, accurate and highly precise. Attached Figure Description

[0032] 1. Figure 1 The separation spectra of the internal standard (α-aminocaprolactam) and the non-toxic propellant sample 1 in the sample solution of Example 1 are as follows: 8.862 min: other components; 14.886 min: functional additive 2-dimethylaminoethylhydrazine nitrate; 15.748 min: internal standard α-aminocaprolactam.

[0033] 2. Figure 2 The separation spectra of the internal standard and the non-toxic propellant sample 1# under the chromatographic conditions in Comparative Example 1 are shown below; 8.938 min: other components; 15.940 min: functional additive 2-dimethylaminoethylhydrazine nitrate; 16.260 min: internal standard α-aminocaprolactone.

[0034] 3. Figure 3 The separation spectra of the internal standard (triethanolamine) and the non-toxic propellant sample 1 in Comparative Example 2 are as follows: 8.937 min: other components; 14.581 min: internal standard triethanolamine; 14.950 min: functional additive 2-dimethylaminoethylhydrazine nitrate. Detailed Implementation

[0035] Example 1

[0036] The content of 2-dimethylaminoethylhydrazine nitrate in non-toxic propellant sample 1# (a mixture of hydroxylamine nitrate, functional additive 2-dimethylaminoethylhydrazine nitrate, methanol, and water) was determined. The molecular formula of 2-dimethylaminoethylhydrazine nitrate is:

[0037]

[0038] It includes the following steps:

[0039] (1) Preparation of standard solution: Accurately weigh 0.1042 g of non-toxic propellant standard solution 1# (containing 40% (wt%) of hydroxylamine nitrate, 10% (wt%) of functional additive 2-dimethylaminoethylhydrazine nitrate, 25% (wt%) of methanol, and 25% (wt%) of water) and 0.0110 g of internal standard α-aminocaprolactam into a 100 mL volumetric flask, and dilute with water to the mark;

[0040] Preparation of sample solution: Accurately weigh 0.1038g of non-toxic propellant sample 1# and 0.0096g of internal standard α-aminocaprolactam into a 100mL volumetric flask, and dilute with water to the mark.

[0041] (2) The above standard solutions and sample solutions were analyzed by liquid chromatography using an ACE Excel5AQ column (25 cm long, 4.6 mm inner diameter, 5 μm packing particle size, 30 °C). A differential refractive index detector (DRID) with a temperature of 35 °C was used. The column flow rate was 1.0 mL / min, the injection volume was 5 μL, and the mobile phase consisted of A (20 mmol potassium dihydrogen phosphate aqueous solution) and B (acetonitrile). Isocratic elution was performed. Mobile phase A was 65% (V / V), and mobile phase B was 35% (V / V). The standard solutions and sample solutions were each measured 5 times. The peak areas of the internal standard α-aminocaprolactam and the functional additive 2-dimethylaminoethylhydrazine nitrate are shown in Table 1 and Table 2, respectively.

[0042] Table 1 Peak areas of internal standards and functional additives in standard solutions

[0043]

[0044] Table 2 Peak areas of internal standards and functional additives in the sample solution

[0045]

[0046] Substitute the average peak area of ​​the internal standard and functional additive in the standard solution into formula (1) to calculate the relative calibration factor:

[0047]

[0048] Substitute the relative calibration factor f, the peak areas of the internal standard and functional additives in each parallel sample solution in Table 2 into formula (2) to calculate the content of 2-dimethylaminoethylhydrazine nitrate in the propellant. For example, substitute the peak area of ​​parallel sample 1# into formula (2):

[0049]

[0050] The results of the five parallel tests were calculated to be 9.30%, 9.40%, 9.32%, 9.44%, and 9.61%, with an average of 9.41% and a relative standard deviation (RSD) of 1.17%, indicating that the results had good repeatability.

[0051] The accuracy of the method was verified by measuring the spiked recovery rate of the sample. 0.2136 g of the sample solution whose concentration had been determined according to the above steps was weighed, and 20.5 mg of 2-dimethylaminoethylhydrazine nitrate was added. The solution was then tested according to steps (1) and (2) above. The difference between the measured 2-dimethylaminoethylhydrazine nitrate content and the 2-dimethylaminoethylhydrazine nitrate content in the sample solution was obtained. The ratio of the difference to the known amount of 20.5 mg added was the spiked recovery rate. The method was repeated twice. The specific results are shown in Table 3. As can be seen from Table 3, the spiked recovery rate of 2-dimethylaminoethylhydrazine nitrate was 98.3%, indicating that the accuracy of the method is high and can meet the requirements of quantitative analysis.

[0052] Table 3 Spike Recovery Rate of Example 1

[0053]

[0054] Example 2

[0055] Determination of 2-methylaminoethylhydrazine nitrate content in non-toxic propellant sample 2# (components: hydroxylamine nitrate / functional additive 2-methylaminoethylhydrazine nitrate / methanol / water); molecular formula of 2-methylaminoethylhydrazine nitrate:

[0056]

[0057] It includes the following steps:

[0058] (1) Preparation of standard solution: Accurately weigh 0.1034 g of non-toxic propellant standard solution 2# (containing 40% (wt%) of hydroxylamine nitrate, 20% (wt%) of functional additive 2-methylaminoethylhydrazine nitrate, 25% (wt%) of methanol, and 25% (wt%) of water) and 0.0212 g of internal standard α-aminocaprolactam into a 100 mL volumetric flask, and dilute with water to the mark;

[0059] Preparation of sample solution: Accurately weigh 0.1145g of non-toxic propellant sample 2# and 0.0208g of internal standard α-aminocaprolactam into a 100mL volumetric flask, and dilute with water to the mark.

[0060] (2) The above sample solution and standard solution were subjected to liquid chromatography analysis using an ACE Excel5AQ column (25cm, 4.6mm inner diameter, 5µm packing particle size), a column temperature of 30℃, a differential refractive index detector (35℃), a column flow rate of 1.0mL / min, an injection volume of 5µL, and mobile phases A (20mmol potassium dihydrogen phosphate aqueous solution) and B (acetonitrile), with isocratic elution. Mobile phase A was 65% (V / V), and mobile phase B was 35% (V / V). The standard solution and sample solution were measured 5 times each. (Substitute into formulas (1) and (2) to calculate the content of functional additives in the sample to be tested.) The results were 19.68%, 19.80%, 19.92%, 20.14%, and 20.37%, respectively. The average peak areas of the internal standard and functional additive in the standard solution were 1560.82 mV·min and 1488.64 mV·min, respectively. The average peak areas of the internal standard and functional additive in the sample solution were 1384.25 mV·min and 1488.21 mV·min, respectively. The content of 2-methylaminoethylhydrazine nitrate in the sample was calculated by substituting into formulas (1) and (2) in the same way as in Example 1. The average value was 19.98%, and the relative standard deviation (RSD) was 1.23%, indicating that the repeatability of the results was good.

[0061] The accuracy of the method was verified by the spiked recovery rate of the sample. 0.1523g of the sample solution whose concentration had been determined according to the above steps was weighed, and 31.4mg of 2-methylaminoethylhydrazine nitrate solution was added. The test was performed according to steps (1) and (2) above. The spiked recovery rate was calculated according to the same method as in Example 1. The results are shown in Table 4. As can be seen from Table 4, the spiked recovery rate of 2-methylaminoethylhydrazine nitrate was 100.2%, which indicates that the accuracy of the method is high and can meet the requirements of quantitative analysis.

[0062] Table 4 Spike Recovery Rate of Example 2

[0063]

[0064] Example 3

[0065] Determination of 2-hydrazinoethylhydrazine nitrate content in non-toxic propellant sample 3# (components: hydroxylamine nitrate / functional additive 2-hydrazinoethylhydrazine nitrate / methanol / water). Molecular formula of 2-hydrazinoethylhydrazine nitrate:

[0066]

[0067] It includes the following steps:

[0068] (1) Preparation of standard solution: Accurately weigh 0.1236 g of non-toxic propellant standard solution No. 3 (containing 40% (wt%) of hydroxylamine nitrate, 25% (wt%) of functional additive 2-hydrazinoethylhydrazine nitrate, 25% (wt%) of methanol, and 25% (wt%) of water) and 0.0212 g of internal standard α-aminocaprolactam into a 100 mL volumetric flask, and dilute with water to the mark;

[0069] Preparation of sample solution: Accurately weigh 0.1278 g of non-toxic propellant sample 3# and 0.0236 g of internal standard α-aminocaprolactam into a 100 mL volumetric flask, and dilute with water to the mark.

[0070] (2) The above sample solution and standard solution were subjected to liquid chromatography analysis using an ACE Excel5AQ column (25 cm long, 4.6 mm inner diameter, 5 μm packing particle size), a column temperature of 30 °C, a differential refractive index detector (DRID) at 35 °C, a column flow rate of 1.0 mL / min, an injection volume of 5 μL, and mobile phases consisting of A (20 mmol potassium dihydrogen phosphate aqueous solution) and B (acetonitrile), with isocratic elution. Mobile phase A was 65% (V / V), and mobile phase B was 35% (V / V). The standard solution and sample solution were measured 5 times each (the work in the sample was calculated by substituting into formulas (1) and (2)). The content of functional additives was calculated to be 25.36%, 24.90%, 25.27%, 24.84%, and 25.14%, respectively. The average peak areas of the internal standard and functional additives in the standard solution were 1345.67 mV·min and 1822.45 mV·min, respectively, and the average peak areas of the internal standard and functional additives in the sample solution were 1478.45 mV·min and 1866.90 mV·min, respectively. The content of 2-hydrazinoethylhydrazine nitrate in the sample was calculated to be 25.10% according to formulas (1) and (2). The relative standard deviation (RSD) was 0.81%, indicating that the repeatability of the results was good.

[0071] The accuracy of the method was verified by the spiked recovery rate of the sample. 0.1290g of the sample solution whose concentration had been determined according to the above steps was weighed, and 22.4mg of 2-hydrazinoethylhydrazine nitrate solution was added. The test was carried out according to the above steps (1) and (2). The spiked recovery rate was calculated in the same way as in Example 1. The results are shown in Table 5. As can be seen from Table 5, the spiked recovery rate of 2-hydrazinoethylhydrazine nitrate was 100.2%, and the average value was 25.10%, which indicates that the accuracy of the method is high and can meet the requirements of quantitative analysis.

[0072] Table 5 Spike Recovery Rate in Example 2

[0073]

[0074] Example 4

[0075] Determination of 2-aminoethylhydrazine nitrate content in non-toxic propellant sample 4# (components: hydroxylamine nitrate / functional additive 2-aminoethylhydrazine nitrate / methanol / water). Molecular formula of 2-aminoethylhydrazine nitrate:

[0076]

[0077] It includes the following steps:

[0078] (1) Preparation of standard solution: Accurately weigh 0.1139 g of non-toxic propellant standard solution 4# (containing 40% (wt%) of hydroxylamine nitrate, 32% (wt%) of functional additive 2-aminoethylhydrazine nitrate, 25% (wt%) of methanol, and 25% (wt%) of water) and 0.0293 g of internal standard α-aminocaprolactam into a 100 mL volumetric flask, and dilute with water to the mark;

[0079] Preparation of sample solution: Accurately weigh 0.1220 g of non-toxic propellant sample 4# and 0.0282 g of internal standard α-aminocaprolactam into a 100 mL volumetric flask, and dilute with water to the mark.

[0080] (2) The above sample solution and standard solution were subjected to liquid chromatography analysis using an ACE Excel5AQ column (25 cm long, 4.6 mm inner diameter, 5 μm packing particle size), a column temperature of 30 °C, a differential refractive index detector (DRID) at 35 °C, a column flow rate of 1.0 mL / min, an injection volume of 5 μL, and mobile phases consisting of A (20 mmol potassium dihydrogen phosphate aqueous solution) and B (acetonitrile), with isocratic elution. Mobile phase A was 65% (V / V), and mobile phase B was 35% (V / V). The standard solution and sample solution were measured 5 times each (the work in the sample was calculated by substituting into formulas (1) and (2)). The content of functional additives was calculated to be 31.57%, 32.14%, 31.74%, 32.36%, and 31.88%, respectively. The average peak areas of the internal standard and functional additives in the standard solution were 1645.88 mV·min and 1935.66 mV·min, respectively, and the average peak areas of the internal standard and functional additives in the sample solution were 1744.67 mV·min and 2279.74 mV·min, respectively. The content of 2-aminoethylhydrazine nitrate in the sample was calculated to be 31.94% according to formulas (1) and (2). The relative standard deviation (RSD) was 0.88%, indicating that the repeatability of the results was good.

[0081] The accuracy of the method was verified by the spiked recovery rate of the sample. 0.1156g of the sample solution whose concentration had been determined according to the above steps was weighed, and 25.8mg of 2-aminoethylhydrazine nitrate solution was added. The test was carried out according to the above steps (1) and (2). The spiked recovery rate was calculated using the same method as in Example 1. The results are shown in Table 6. As can be seen from Table 6, the spiked recovery rate of 2-aminoethylhydrazine nitrate was 100.4%, indicating that the accuracy of the method is high and can meet the requirements of quantitative analysis.

[0082] Table 6 Spike Recovery Rate of Example 2

[0083]

[0084] Comparative Example 1

[0085] The determination of 2-dimethylaminoethylhydrazine nitrate content in non-toxic propellant sample 1# (components: hydroxylamine nitrate / functional additive 2-dimethylaminoethylhydrazine nitrate / methanol / water) includes the following steps:

[0086] (1) Preparation of standard solution: Accurately weigh 0.1g of non-toxic propellant standard solution 1# (containing 40% (wt%) of hydroxylamine nitrate, 10% (wt%) of functional additive 2-dimethylaminoethylhydrazine nitrate, 25% (wt%) of methanol, and 25% (wt%) of water) and 0.01g of internal standard α-aminocaprolactam into a 100mL volumetric flask, and dilute with water to the mark;

[0087] Preparation of sample solution: Accurately weigh 0.1g of non-toxic propellant sample 1# and 0.01g of internal standard α-aminocaprolactam into a 100mL volumetric flask, and dilute with water to the mark.

[0088] (2) The above sample solution and standard solution were subjected to liquid chromatography analysis using an ACE Excel 5AQ column with a length of 25 cm, an inner diameter of 4.6 mm, a packing particle size of 5 μm, a differential refractive index detector, a column temperature of 30 °C, a detector temperature of 40 °C, a column flow rate of 1.0 mL / min, an injection volume of 5 μL, and mobile phase A consisting of 100% water and 100% acetonitrile, with isocratic elution. The content of mobile phase A was 90%, and the content of mobile phase B was 10%.

[0089] From the appendix Figure 2 It is evident that under these chromatographic conditions, the functional additive 2-dimethylaminoethylhydrazine nitrate and the internal standard α-aminocaprolactone cannot be effectively separated, and the peak areas cannot be accurately integrated, thus preventing accurate quantification.

[0090] Comparative Example 2

[0091] The determination of 2-dimethylaminoethylhydrazine nitrate content in non-toxic propellant sample 1# (components: hydroxylamine nitrate / functional additive 2-dimethylaminoethylhydrazine nitrate / methanol / water) includes the following steps:

[0092] (1) Preparation of standard solution: Accurately weigh 0.1g of non-toxic propellant standard solution 1# (containing 40% (wt%) of hydroxylamine nitrate, 10% (wt%) of functional additive 2-dimethylaminoethylhydrazine nitrate), 25% (wt%) of methanol, 25% (wt%) of water) and 0.01g of internal standard triethanolamine into a 100mL volumetric flask, and dilute with water to the mark;

[0093] Preparation of sample solution: Accurately weigh 0.1g of non-toxic propellant sample 1# and 0.01g of internal standard triethanolamine into a 100mL volumetric flask, and dilute with water to the mark.

[0094] (2) The above sample solution and standard solution were subjected to liquid chromatography analysis. An ACE Excel 5AQ column was used, with a column length of 25 cm, an inner diameter of 4.6 mm, a packing particle size of 5 μm, and a differential refractive index detector. The column temperature was 30 °C, the detector temperature was 40 °C, the column flow rate was 1.0 mL / min, the injection volume was 5 μL, and the mobile phase composition was A (20 mmol potassium dihydrogen phosphate aqueous solution) and B (acetonitrile). Isocratic elution was performed, with mobile phase A being 65% and mobile phase B being 35%. The content of the functional additive 2-dimethylaminoethylhydrazine nitrate in the sample was calculated according to formula (2).

[0095] From the appendix Figure 3 It is evident that under these chromatographic conditions, the functional additive 2-dimethylaminoethylhydrazine nitrate and the internal standard triethanolamine cannot be effectively separated, and the peak areas cannot be accurately integrated, thus preventing accurate quantification.

Claims

1. A method for detecting (2-alkylamino / hydrazino)ethylhydrazine nitrate in propellants, characterized in that, Includes the following steps: (1) Using α-aminocaprolactam as an internal standard, the standard sample and the sample to be tested were dissolved and diluted with methanol and / or water to obtain the standard solution and the sample solution, respectively. (2) Perform liquid chromatography analysis on the standard solution and sample solution obtained in step (1). The stationary phase of the chromatographic column is a C18 column with polar functional group end caps. The column length is 10-30 cm, the inner diameter is 2.1-4.6 mm, the particle size of the packing is 3-10 μm, the detector is a differential refractive index detector, the detector temperature is 30-50 °C, the column temperature is 20-40 °C, the mobile phase composition is A (potassium dihydrogen phosphate aqueous solution) and B (100% methanol or acetonitrile), the flow rate is 0.2-1.5 mL / min, isocratic elution is used, and the injection volume is 2-10 μL. Calculate the content of functional adjuvant (2-alkylamino / hydrazyl) ethylhydrazine nitrate in the sample to be tested based on the peak area of ​​functional adjuvant (2-alkylamino / hydrazyl) ethylhydrazine nitrate in the standard solution and sample solution.

2. The detection method as described in claim 1, characterized in that, In step (2), the column temperature is preferably 25-35℃, more preferably 30-32℃; the column flow rate is preferably 0.8-1.2mL / min, more preferably 0.9-1.0mL / min; and the injection volume is preferably 3-7 μL, more preferably 5-6 μL.

3. The detection method as described in claim 1, characterized in that, In step (2), the preferred chromatographic column is the ACE Excel 5AQ column, with a more effective specification of 25cm column length, 4.6mm inner diameter, and 5um packing particle size.

4. The detection method as described in claim 1, characterized in that, In step (2), the concentration of potassium dihydrogen phosphate in mobile phase A is 10-50 mmol, and mobile phase B is 100% acetonitrile.

5. The detection method as described in claim 1, characterized in that, Step (2) involves moderate elution, with mobile phase A having a volume content of 50-90%, preferably 60-80%, more preferably 65-75%, and mobile phase B having a volume content of 10-50%, preferably 20-40%, more preferably 25-35%.

6. The detection method as described in claim 1, characterized in that, In step (2), the temperature of the differential detector is 35℃.

7. The detection method as described in claim 1, characterized in that, In step (2), the content of functional additive (2-alkylamino / hydrazino) ethylhydrazine nitrate in the sample to be tested is calculated according to the following formula: In the formula: f—relative calibration factor; m n —The mass of functional adjuvant (2-alkylamino / hydrazino) ethylhydrazine nitrate in the standard solution; A n —Peak area of ​​functional adjuvant (2-alkylamino / hydrazino) ethylhydrazine nitrate in standard solution; A s —Peak area of ​​the internal standard in the standard solution; m s —The mass of the internal standard in the standard solution; W i —The mass percentage of functional additive (2-alkylamino / hydrazino) ethylhydrazine nitrate in the sample to be tested; A i —Peak area of ​​functional additive (2-alkylamino / hydrazino) ethylhydrazine nitrate in the sample solution; A1—Peak area of ​​the internal standard in the sample solution; m1 — the mass of the internal standard in the sample solution; m i —Weigh the mass of the non-toxic propellant sample to be tested.

8. The detection method as described in claim 1, characterized in that, In step (1), The amount of α-aminocaprolactam in each 100 mL standard solution is 0.01–0.03 g, preferably 0.01–0.02 g, and the amount of standard is 0.1–0.3 g, preferably 0.1–0.2 g; The amount of α-aminocaprolactam in each 100 mL sample solution is 0.01–0.03 g, preferably 0.01–0.02 g, and the amount of the sample to be tested is 0.1–0.3 g, preferably 0.1–0.2 g. The sample to be tested is a hydroxylamine nitrate-based green propellant with or without the functional additive (2-alkylamine / hydrazine) ethyl hydrazine nitrate.

9. The detection method as described in claim 1, characterized in that, The structural formula of (2-alkylamino / hydrazino)ethylhydrazine nitrate is: R1 is one of hydrogen, methyl or amino, and R2 is one of hydrogen, methyl, ethyl, n-propyl or n-butyl.

10. The detection method as described in claim 1 or 9, characterized in that, The functional additive (2-alkylamino / hydrazine) ethylhydrazine nitrate is one or more of 2-aminoethylhydrazine nitrate, 2-methylaminoethylhydrazine nitrate, 2-dimethylaminoethylhydrazine nitrate, 2-hydrazylethylhydrazine nitrate, 2-ethylaminoethylhydrazine nitrate, and 2-diethylaminoethylhydrazine nitrate.

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