Method for detecting content of methanol in nitrocotton

Abstract

The invention provides a method for detecting the content of methanol in nitrocotton, and belongs to the technical field of chemical cellulose production, and the method comprises the following steps: dissolving nitrocotton in a lipid substance to obtain a lipid solution of nitrocotton; dissolving methanol into the lipid substance to obtain a methanol standard solution; injecting methanol standard solutions with different mass concentrations into a gas chromatograph to obtain a methanol content-peak area standard curve; injecting the lipid solution of the nitrocotton into a gas chromatograph, and calculating the content of methanol in the lipid solution of the nitrocotton according to the methanol content-peak area standard curve. The method for detecting the content of the methanol in the nitrocotton product is established by adopting the gas chromatograph, and the content of the methanol in the nitrocotton product is detected, so that the index requirement for controlling the content of the methanol in the nitrocotton is met.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical cellulose production, and more specifically, relates to a method for detecting the methanol content in nitrocellulose. Background Art

[0002] Nitrocellulose is an important chemical raw material, mainly used as industrial explosives and gunpowder. The scientific name of nitrocellulose is cellulose nitrate, also known as nitrocellulose, abbreviated as NC. Nitrocellulose is a compound generated by the nitro group replacing the hydrogen of the hydroxyl group of the cellulose molecule after the action of nitric acid and cotton fiber.

[0003] In response to the requirement put forward by nitrocellulose users to control the methanol content in products, a detection method for the methanol content in nitrocellulose needs to be established. Currently, there is no detection method for the methanol content in nitrocellulose. Summary of the invention

[0004] The purpose of the present invention is to provide a method for detecting the methanol content in nitrocellulose, so as to detect the methanol content in nitrocellulose and control the methanol content in the nitrocellulose product to meet the production index requirements.

[0005] To achieve the above object, the present invention provides a method for detecting the methanol content in nitrocellulose, comprising the following steps:

[0006] Dissolving nitrocellulose in lipid substances to obtain a nitrocellulose lipid solution;

[0007] dissolving methanol in the lipid substance to obtain a methanol standard solution;

[0008] Injecting the methanol standard solutions of different mass concentrations into a gas chromatograph to obtain a methanol content-peak area standard curve;

[0009] The nitrocellulose lipid solution is injected into the gas chromatograph, and the methanol content in the nitrocellulose lipid solution is calculated according to the methanol content-peak area standard curve.

[0010] Furthermore, the lipid substance is ethyl acetate or butyl acetate.

[0011] Furthermore, external standards are added to both the nitrocellulose lipid solution and the methanol standard solution.

[0012] Furthermore, the external standard is n-heptane.

[0013] Furthermore, the gas chromatograph is a FID gas chromatograph.

[0014] Furthermore, the temperature rise program of the gas chromatograph is as follows: the first stage temperature rise rate is set to 0°C / min, the end temperature is 50°C, and the holding time is 4min; the second stage temperature rise rate is set to 30°C / min, the end temperature is 280°C, and the holding time is 2min.

[0015] Compared with the prior art, the present invention has the following technical effects:

[0016] The invention adopts a gas chromatograph to establish a method for detecting the methanol content in a nitrocellulose product, and detects the methanol content in the nitrocellulose product to meet the index requirement for controlling the methanol content in the nitrocellulose. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the 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.

[0018] It should be understood that in various embodiments of the present invention, the size of the serial number of each process does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0019] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0020] The weight of the relevant components mentioned in the description of the embodiments of the present invention may not only refer to the specific content of each component, but also indicate the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the description of the embodiments of the present invention, it is within the scope disclosed in the description of the embodiments of the present invention. Specifically, the mass described in the description of the embodiments of the present invention may be μg, mg, g, kg, or other mass units known in the biochemical field.

[0021] The embodiment of the present invention provides a method for detecting the methanol content in nitrocellulose, and the detection method is based on the following principles:

[0022] Use a gas chromatograph under specified working conditions to separate the methanol in the prepared methanol standard solution and assign a value. Then prepare the sample solution with the nitrocellulose sample or directly absorb the alcohol sample as the sample, separate the methanol under the same gas chromatograph working conditions, and use the external standard method to obtain the methanol content in the sample.

[0023] The present invention provides a method for detecting methanol content in nitrocellulose, comprising the following steps:

[0024] (1) Nitrocellulose is miscible with esters, and esters do not react chemically with nitrocellulose and methanol. Therefore, a lipid reagent such as ethyl acetate or butyl acetate can be used to dissolve the nitrocellulose sample to prepare a sample solution. Specifically, the nitrocellulose is dissolved in a lipid to obtain a nitrocellulose lipid solution; the lipid can be ethyl acetate or butyl acetate;

[0025] (2) dissolving methanol in the above lipid substances to prepare a methanol standard solution; specifically, weighing a certain amount of methanol as a solute, and then using the same lipid reagent as that used to dissolve the nitrocellulose sample as a solvent to make up the volume to prepare a standard solution, and calculating the methanol content in the standard solution;

[0026] (3) injecting methanol standard solutions of different mass concentrations into a gas chromatograph to obtain a methanol content-peak area standard curve; specifically, using a micro-syringe to draw different quantitative methanol standard solutions in sequence, and injecting them from the injection port into a hydrogen flame gas chromatograph under a certain temperature program for separation, inputting the methanol content of the standard solution at the methanol peak, and saving it as a method;

[0027] (4) Inject the nitrocellulose lipid solution into a gas chromatograph, and calculate the methanol content in the nitrocellulose lipid solution according to a standard curve of methanol content-peak area. Specifically, use a microsyringe to draw a quantitative nitrocellulose sample solution, inject it from the injection port into a hydrogen flame gas chromatograph under a certain temperature program for separation, and select the method saved in step (3) to detect the methanol content in the nitrocellulose.

[0028] The embodiment of the present invention uses a gas chromatograph to establish a method for detecting the methanol content in a nitrocellulose product, and detects the methanol content in the nitrocellulose product to meet the index requirement for controlling the methanol content in the nitrocellulose.

[0029] The following is a specific example to illustrate a method for detecting methanol content in nitrocellulose according to an embodiment of the present invention:

[0030] 1. The reagents and raw materials used in the embodiments of the present invention are as follows:

[0031] a: Methanol, GB / T683, analytical grade;

[0032] b: Ethyl acetate, GB / T12589, analytical grade;

[0033] c: n-heptane, GB / T497, analytical grade.

[0034] 2. The instruments and equipment used in the embodiments of the present invention are as follows:

[0035] a: FID gas chromatograph;

[0036] b: Analytical balance, graduation value 0.0001g;

[0037] c: Volumetric flask, 100mL;

[0038] d: medicine spoon;

[0039] e: micro syringe, 10uL;

[0040] f: Syringe, 10mL;

[0041] g: Hydrogen generator;

[0042] h: Nitrogen generator.

[0043] 3. The specific test process of the embodiment of the present invention is as follows:

[0044] 3.1 Analysts should wear cotton work clothes and work shoes.

[0045] 3.2 Use a 10mL syringe to draw and weigh 0.03g±0.003g of methanol and 0.08g±0.003g of n-heptane into a dry, clean and intact volumetric flask, then use ethyl acetate to make up to 100mL and plug the volumetric flask.

[0046] 3.3 Weigh 2.0±0.003g of nitrocellulose sample into a dry, clean and intact volumetric flask. Use a syringe to draw out and weigh 0.08g±0.003g of n-heptane and place it into the volumetric flask. Use ethyl acetate to make the volume up to 100mL. Plug the volumetric flask and shake to completely dissolve the nitrocellulose sample.

[0047] 3.4 Turn on the nitrogen generator and hydrogen generator, and then turn on the FID gas chromatograph after the nitrogen generator and hydrogen generator reach the minimum working pressure.

[0048] 3.5 Open the chromatography software and control the temperature of the vaporization chamber, column box, and detector. After the temperature of the vaporization chamber, column box, and detector reaches the specified temperature and remains constant, click "Ignition".

[0049] 3.6 Click "Program" on the gas chromatograph display screen, set the first-stage heating rate to 0℃ / min, the end temperature to 50℃, and the holding time to 4min; the second-stage heating rate to 30℃ / min, the end temperature to 280℃, and the holding time to 2min.

[0050] 3.7 Use a micro syringe to draw about 2uL of methanol standard solution to rinse the syringe twice, then draw 0.4uL of methanol standard solution and inject it into the gas chromatograph vaporization chamber from the gas chromatograph injection port. Immediately click Chengsheng Analysis, and end the analysis after the n-heptane peak is gone.

[0051] 3.8 Save the methanol standard solution spectrum, then use the "spectrum processing tool" to integrate the methanol standard solution spectrum, use the external standard method to name "methanol" at the first peak and enter the concentration in mg / L. Repeat steps 3.7 and 3.8, and then draw 0.6uL, 0.8uL, 1.0uL, and 1.2uL of methanol standard solution in turn, and inject them into the chromatograph vaporization chamber from the gas chromatograph injection port in turn to obtain the methanol content-peak area standard curve, and save it as the methanol standard solution method.

[0052] 3.9 After the entire process of upgrading is completed (i.e. the column box temperature drops to the initial constant temperature), use a micro-syringe to draw about 2ul of sample solution to rinse the syringe twice, then draw 0.4ul of sample solution and inject it into the chromatograph vaporization chamber from the gas chromatograph inlet. Analyze the methanol content in the nitrocellulose sample, then immediately click on the upgrade analysis, and end the analysis after the n-heptane peak is gone.

[0053] 3.10 Save the sample solution spectrum, then use the "spectrum processing tool" to integrate the sample solution spectrum, transfer the methanol standard solution method, and the methanol concentration will be displayed in the component table.

[0054] 3.11 After the test is completed, the nitrocellulose sample solution is recovered into the nitrocellulose solution collection bucket. The remaining nitrocellulose sample is recovered into the nitrocellulose collection bucket of the physical and chemical process and covered with water.

[0055] 3.12 Click "End Temperature Control" on the gas chromatograph display screen. When the temperatures of the vaporization chamber, column box, and detector are all below 80°C, press the chromatograph power button to turn off the chromatograph, and turn off the hydrogen generator, nitrogen generator, and air compressor.

[0056] 3.13 Test result processing

[0057] Each sample solution is measured once, and the methanol concentration shown in the component table is the methanol content in the sample, and the result is expressed to one decimal place.

[0058] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the attached claims.

Claims

1. A method for detecting methanol content in nitrocellulose, characterized in that: The following steps are involved: Dissolving nitrocellulose in lipid substances to obtain a nitrocellulose lipid solution; dissolving methanol in the lipid substance to obtain a methanol standard solution; Injecting the methanol standard solutions of different mass concentrations into a gas chromatograph to obtain a methanol content-peak area standard curve; The nitrocellulose lipid solution is injected into the gas chromatograph, and the methanol content in the nitrocellulose lipid solution is calculated according to the methanol content-peak area standard curve.

2. The method for detecting the methanol content in nitrocellulose according to claim 1, characterized in that: The lipid substance is ethyl acetate or butyl acetate.

3. The method for detecting the methanol content in nitrocellulose according to claim 1, characterized in that: External standard substances are added to the nitrocellulose lipid solution and the methanol standard solution.

4. The method for detecting the methanol content in nitrocellulose according to claim 3, characterized in that: The external standard is n-heptane.

5. The method for detecting the methanol content in nitrocellulose according to any one of claims 1 to 4, characterized in that: The gas chromatograph is a FID gas chromatograph.

6. The method for detecting the methanol content in nitrocellulose according to claim 5, characterized in that: The temperature rise program of the gas chromatograph is as follows: the first stage temperature rise rate is set at 0°C / min, the end temperature is 50°C, and the holding time is 4min; the second stage temperature rise rate is set at 30°C / min, the end temperature is 280°C, and the holding time is 2min.