An analytical method for determining the hydrogenation rate of hydrogenated nitrile butyral
The hydrogenation rate of hydrogenated nitrile butadiene rubber can be directly determined by one-dimensional nuclear magnetic resonance diffusion ordering spectroscopy, which solves the problems of cumbersome procedures and environmental pollution in traditional methods and realizes rapid, accurate and safe detection of hydrogenation rate of hydrogenated nitrile butadiene rubber.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PETROCHINA SHANGHAI ADVANCED MATERIALS RESEARCH INSTITUTE CO LTD
- Filing Date
- 2024-11-27
- Publication Date
- 2026-05-29
AI Technical Summary
There is a lack of a fast, accurate, safe and convenient method to determine the hydrogenation rate of hydrogenated nitrile rubber, especially when the determination is carried out in solution. Traditional methods have problems such as cumbersome steps, long time, high cost, environmental pollution and health hazards.
One-dimensional nuclear magnetic resonance diffusion ordering spectroscopy (DOSY) was used to directly test hydrogenated nitrile butadiene nitrile samples containing solvent. The diffusion coefficients of solvent and hydrogenated nitrile butadiene nitrile were distinguished by the one-dimensional nuclear magnetic resonance diffusion ordering spectrum, the hydrogenation rate was calculated, and high-field or low-field nuclear magnetic resonance spectrometers were used for analysis.
This method enables rapid and accurate determination of the hydrogenation rate of hydrogenated butyronitrile in solution, simplifies sample processing steps, reduces costs, minimizes environmental pollution and health hazards, and improves detection efficiency and sensitivity.
Smart Images
Figure CN122109173A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of materials analysis and testing technology, specifically to an analytical method for the hydrogenation rate of hydrogenated butyronitrile, particularly to an analytical method for the hydrogenation rate of hydrogenated butyronitrile containing solvent, and especially to an analytical method for determining the hydrogenation rate of hydrogenated butyronitrile. Background Technology
[0002] Hydrogenated nitrile butadiene rubber (HNBR), also known as highly saturated nitrile butadiene rubber, is a rubber material with a highly saturated molecular backbone. It is produced by hydrogenating nitrile butadiene rubber (NBR). The hydrogenation reaction reduces the number of unsaturated double bonds in the rubber chain, allowing HNBR to retain the original nitrile butadiene rubber's oil resistance, media resistance, and abrasion resistance while improving its overall properties such as heat resistance, weather resistance, and chemical corrosion resistance, especially its heat aging performance. Controlling a small amount of butadiene residue provides a cross-linked network structure for the rubber, maintaining its elastic characteristics. Therefore, HNBR has wide applications in the automotive, petroleum, machinery, and aerospace industries. Currently, only a few companies in China can produce HNBR, and there is still a significant technological gap compared to international companies such as Lanxess and Rayon. HNBR is a new type of elastomer that combines high technology and high profit, possessing enormous market potential. It requires innovative production technologies and rapid R&D iteration to enhance the competitiveness of enterprises in both domestic and international markets.
[0003] The degree of hydrogenation is one of the key factors affecting the performance of hydrogenated nitrile butadiene rubber. Developing a rapid and accurate method to measure the hydrogenation rate of hydrogenated nitrile butadiene rubber during the production and R&D process can improve production and R&D efficiency, shorten R&D time, and enhance product competitiveness, which is of great significance to the hydrogenated nitrile butadiene rubber industry.
[0004] The traditional iodine value method, SH / T 1763-2020 "Determination of Residual Unsaturation in Hydrogenated Nitrile Butadiene Rubber (HNBR)," uses Wijk's reagent to determine the residual unsaturation of hydrogenated nitrile butadiene rubber and is applicable to hydrogenated nitrile butadiene rubber. The hydrogenated nitrile butadiene sample is dissolved in chloroform, an excess of Wijk's reagent is added, and the mixture is allowed to stand for a period of time to allow the Wijk's reagent to react completely with the residual unsaturated double bonds. The unreacted Wijk's reagent is neutralized with potassium iodide solution, and the free iodine in the sample is titrated with sodium thiosulfate standard solution to calculate the iodine value (unsaturation). The entire testing process is cumbersome and time-consuming (testing one sample requires at least 4 hours), resulting in relatively low efficiency. Besides reacting with the double bonds from hydrogenated nitrile butadiene rubber, the iodine value method can also react with other components, such as stabilizers, antioxidants, and some solvents, thus affecting the accuracy of this method in certain situations. This method also suffers from high time, economic, and labor costs. The iodine value method uses a relatively large variety and quantity of chemicals, which can easily pollute the environment and harm the health of operators. This method also has the problem of high requirements for the operating environment (temperature, reaction time, light, etc. are all required).
[0005] The infrared spectroscopy method SH / T 1762-2008, "Determination of Residual Unsaturation of Hydrogenated Nitrile Butadiene Rubber (HNBR) by Infrared Spectroscopy," is applicable to the determination of residual unsaturation in raw rubber samples. The raw rubber is first dissolved in methyl ethyl ketone (MEK) solvent, then coated onto a potassium bromide (KBr) film. The infrared spectrum of the film is obtained using Fourier transform (FT) or dispersive infrared spectroscopy. The degree of hydrogenation is calculated from the absorption constants of the absorption peaks at 2236 cm⁻¹, 970 cm⁻¹, and 727 cm⁻¹ in the FT-IR spectrum. During infrared testing, solvent evaporation occurs, and the evaporated sample significantly affects the accuracy of the quantitative results. Furthermore, the volatiles can pollute the environment and harm the health of operators. This test requires high precision in film thickness and uniformity, and places high demands on the operator's skills.
[0006] The method of 1H NMR involves dissolving the sample in deuterated chloroform and testing the 1H NMR spectrum. By detecting signals such as α-H of -CN at 2.6 ppm and double bonds at 5.5 ppm and 5.0 ppm, the degree of hydrogenation, the residual double bonds, and the acrylonitrile content can be calculated.
[0007] The above three methods are all for the analysis of raw rubber samples. In actual R&D and production, the hydrogenation process of nitrile rubber is mostly carried out in solution. For such hydrogenated nitrile rubber samples, all three methods require flocculating the rubber from the reaction solution or drying it to remove the solvent to obtain the rubber sample, and then determining the hydrogenation rate of the sample according to the corresponding testing method. For R&D samples, drying is a common method for removing solvents. However, the drying process may cause residual olefins to crosslink and become difficult to dissolve, or leave solvent residues, affecting subsequent tests. In summary, there is still a lack of a rapid, reliable, safe, convenient, and accurate method for testing the hydrogenation rate of hydrogenated nitrile rubber in solution. Summary of the Invention
[0008] The purpose of this invention is to overcome the shortcomings of the existing technology and provide an analytical method for determining the hydrogenation rate of hydrogenated nitrile butadiene oxide (NDI). To achieve this objective, this invention uses a one-dimensional nuclear magnetic resonance (NMR) diffusion ordering spectroscopy (DOSY) acquisition sequence. The sample does not require any pretreatment; it directly tests the hydrogenation rate of NDI samples containing solution. Diffuision Ordered Spectroscopy (DOSY) is an important method for measuring the self-diffusion coefficient D of liquid and solution samples. Stimulated Echo (STE), Longitudinal Eddy Current Delay (LED), and Bipolar Gradient Field (BPP) sequences are the three most commonly used pulse sequences. DOSY is widely used in the analysis of mixture samples, host-guest identification, molecular self-assembly, and the determination of polymer molecular weight through diffusion coefficients. In this invention, the diffusion coefficients of the solvent and the NDI product in the NDI solution differ significantly, providing the possibility of completely distinguishing the NDI and solvent signals on a one-dimensional spectrum. Therefore, by utilizing the difference in diffusion coefficients between the solvent and hydrogenated nitrile butyronitrile, a one-dimensional spectrum containing only the hydrogenated nitrile butyronitrile signal, free from solvent interference, can be obtained through one-dimensional nuclear magnetic resonance diffusion ordering spectroscopy. The resulting one-dimensional spectrum can then be integrated to calculate the hydrogenation rate of the hydrogenated nitrile butyronitrile. This method has broad applicability, suitable not only for high-field nuclear magnetic resonance spectrometers (600 MHz) but also for low-field nuclear magnetic resonance spectrometers (60 MHz).
[0009] This invention can be achieved through the following technical solutions:
[0010] The purpose of this invention is to provide an analytical method for determining the hydrogenation rate of hydrogenated butyronitrile, which is a rapid analytical method for determining the hydrogenation rate of hydrogenated butyronitrile.
[0011] The analytical method for determining the hydrogenation rate of hydrogenated nitrile butyrate includes the following steps:
[0012] S1. Use high-field NMR or low-field NMR to test the hydrogenated nitrile butadiene sample containing solvent, set the sampling parameters, and acquire a one-dimensional NMR diffusion ordering spectrum.
[0013] S2. Obtain the chemical shift and integral area information of hydrogenated butadiene nitrile through one-dimensional nuclear magnetic resonance diffusion sorting spectrum, and calculate the hydrogenation rate of 1,4-butadiene and / or 1,2-butadiene and / or butadiene hydrogenation rate by combining the butadiene nitrile raw material composition information.
[0014] The composition information of the butadiene-nitrile raw material includes acrylonitrile content, 1,4-butadiene content, and 1,2-butadiene content;
[0015] The chemical shift and integral area information corresponding to the hydrogenated butadiene nitrile includes the signal integral area of saturated aliphatic hydrocarbons, the signal integral areas of 1,4-butadiene (CH=CH) and 1,2-butadiene (CH=), and the signal integral area of 1,2-butadiene (CH2=).
[0016] Furthermore, the nitrile raw material is unhydrogenated nitrile.
[0017] Furthermore, the hydrogenated butyronitrile sample is a sample obtained after catalytic hydrogenation of butyronitrile feedstock.
[0018] Further, in step S2, the 1H NMR signal of the butyronitrile raw material is assigned, and it is determined that the signal assignment of all hydrogenated butyronitrile in the one-dimensional NMR diffusion sorting spectrum is consistent with the 1H NMR spectrum of the spectrum. The chemical shift and integral area information of the hydrogenated butyronitrile are obtained through the one-dimensional NMR diffusion sorting spectrum.
[0019] Furthermore, the 1H NMR signals of the butadiene-acrylonitrile feedstock were assigned as follows: saturated aliphatic hydrocarbon signals (0.5–3 ppm), 1,2-butadiene (CH2=) signals (4.8–5.2 ppm), 1,4-butadiene (CH=CH) signals, and 1,2-butadiene (CH=) signals (5.2–5.8 ppm). As the hydrogenation reaction proceeded, the olefin signals decreased, while the saturated aliphatic hydrocarbon signals increased.
[0020] Furthermore, the composition information of the nitrile raw material can be obtained by nuclear magnetic resonance (NMR) spectroscopy.
[0021] Further, in step S2, the hydrogenation rate of 1,4-butadiene is calculated using the following formula:
[0022] 1,4-Butadiene hydrogenation rate = [b / (3a+8b+8c)-(e-1 / 2f) / (4e+3f+2d)] / [b / (3a+8b+8c)] = 1-(e-1 / 2f)*(3a+8b+8c) / [b*(4e+3f+2d)],
[0023] In the formula, a = acrylonitrile content, b = 1,4-butadiene content, c = 1,2-butadiene content, d = signal integration area of saturated aliphatic hydrocarbons, e = signal integration area of 1,4-butadiene (CH=CH) and 1,2-butadiene (CH=) signals, and f = signal integration area of 1,2-butadiene (CH2=) signals.
[0024] Further, in step S2, the hydrogenation rate of 1,2-butadiene is calculated using the following formula:
[0025] 1,2-Butadiene hydrogenation rate = [c / (3a+8b+8c)-f / (4e+3f+2d)] / [c / (3a+8b+8c)] = 1-f*(3a+8b+8c) / [c*(4e+3f+2d)],
[0026] In the formula, a = acrylonitrile content, b = 1,4-butadiene content, c = 1,2-butadiene content, d = signal integration area of saturated aliphatic hydrocarbons, e = signal integration area of 1,4-butadiene (CH=CH) and 1,2-butadiene (CH=) signals, and f = signal integration area of 1,2-butadiene (CH2=) signals.
[0027] Further, in step S2, the butadiene hydrogenation rate is calculated using the following formula:
[0028] Butadiene hydrogenation rate = (content of 1,2-butadiene double bonds before hydrogenation + content of 1,4-butadiene - content of 1,2-butadiene after hydrogenation - content of 1,4 double bonds after hydrogenation) / (content of 1,2 double bonds before hydrogenation + content of 1,4 double bonds before hydrogenation) = (hydrogenated 1,4-butadiene + hydrogenated 1,2-butadiene) / (content of 1,4-butadiene before hydrogenation + content of 1,2-butadiene before hydrogenation) = [b / (3a+8b+8c)+c / (3a+8b+8c)-(e-1 / 2f) / (4e+3f+2d)-f / (4e+3f+2d)] / [b / (3a +8b+8c)+c / (3a+8b+8c)]=1-[(e+1 / 2f)*(3a+8b+8c)] / [(4e+3f+2d)*(b+c)],
[0029] In the formula, a = acrylonitrile content, b = 1,4-butadiene content, c = 1,2-butadiene content, d = signal integration area of saturated aliphatic hydrocarbons, e = signal integration area of 1,4-butadiene (CH=CH) and 1,2-butadiene (CH=) signals, and f = signal integration area of 1,2-butadiene (CH2=) signals.
[0030] Furthermore, in step S1, when using high-field NMR, step S1 includes the following sub-steps:
[0031] A sample of hydrogenated butyronitrile containing solvent was directly added to an NMR tube, followed by the addition of deuterated chloroform. The ledbpgp2s1d pulse sequence (one-dimensional diffusion ordering spectrum) was selected, and the sampling parameters were set as follows: number of scans 8–256, diffusion time Δ(P30) = 1000 μs–2500 μs, and percentage of maximum gradient field intensity GPZ6 = 35%–100%. One-dimensional NMR diffusion ordering spectra were then acquired.
[0032] Furthermore, the number of scans is 16, the diffusion time Δ(P30) = 1200 μs, and the percentage of the maximum gradient field intensity GPZ6 = 95%.
[0033] Furthermore, in step S1, when using low-field NMR, step S1 includes the following sub-steps:
[0034] A sample of hydrogenated nitrile butadiene containing solvent was directly added to an NMR tube. J-PGSE (one-dimensional diffusion ordering spectrum) was selected for testing. The sampling parameters were set as follows: number of scans 8–256, diffusion time Δ(D74) = 10000–30000 μs, and percentage of maximum gradient field intensity G1 = 0.3–1. One-dimensional NMR diffusion ordering spectrum was then acquired.
[0035] Furthermore, the number of scans is 32, the diffusion time Δ(D74) = 12000μs, and the percentage of the maximum gradient field intensity G1 = 0.8.
[0036] Furthermore, the high-field NMR is a 600MHz high-field NMR; the low-field NMR is a 60MHz low-field NMR.
[0037] Further, in step S2, the 1H NMR signal of the nitrile raw material is assigned using one-dimensional nuclear magnetic resonance spectroscopy; the signal of saturated aliphatic hydrocarbons is 0.5-3 ppm, the signal of 1,2-butadiene CH2= is 4.8-5.2 ppm, and the signals of 1,4-butadiene CH=CH and 1,2-butadiene CH= are 5.2-5.8 ppm.
[0038] Furthermore, this invention uses a one-dimensional pulse gradient spin echo sequence for NMR signal collection, which allows for direct testing of the hydrogenation rate of nitrile butyrate in solution without any sample pretreatment.
[0039] Furthermore, the specific testing methods are as follows:
[0040] (1) Sample preparation:
[0041] The hydrogenated nitrile butadiene samples were tested using 600MHz high-field NMR and 60MHz low-field NMR, respectively.
[0042] Oxford 60MHz Low-Field NMR: The 60MHz low-field NMR has a built-in deuterated reagent, eliminating the need for additional deuterated reagents for field locking. Add 0.6 ml of the hydrogenated nitrile butyrate sample containing solvent directly to a 5 ml NMR tube. Select J-PGSE (one-dimensional diffusion ordering spectroscopy), set the sampling parameters: scan number 8–256, diffusion time Δ(D74) = 10000–30000 μs, and percentage of maximum gradient field intensity G1 = 0.3–1. Acquire a one-dimensional NMR diffusion ordering spectrum. Optimal settings include scan number 32, diffusion time Δ(D74) = 12000 μs, and percentage of maximum gradient field intensity G1 = 0.8.
[0043] Bruker 600MHz high-field NMR: Add 0.2–0.3 ml of nitrile butyrate sample directly to a 5 mm NMR tube, add 0.3 ml of deuterated chloroform, select the ledbpgp2s1d pulse sequence (one-dimensional diffusion ordering spectrum), set the sampling parameters: scan number 8–256, diffusion time Δ(P30) = 1000 μs–2500 μs, percentage of maximum gradient field intensity GPZ6 = 35%–100%, and acquire one-dimensional NMR diffusion ordering spectra. Optimal scan number 16, diffusion time Δ(P30) = 1200 μs, and percentage of maximum gradient field intensity GPZ6 = 95%.
[0044] (2) Data analysis and calculation:
[0045] Based on a standard one-dimensional proton spectrum, first compare the proton spectrum signal of the unhydrogenated butyronitrile (HN). Figure 1 Assignment was performed, with signals from saturated aliphatic hydrocarbons (0.5–3 ppm), 1,2-butadiene (CH₂=) (4.8–5.2 ppm), 1,4-butadiene (CH=CH) and 1,2-butadiene (CH=) (5.2–5.8 ppm). As the hydrogenation reaction proceeded, the olefin signal decreased, while the saturated aliphatic hydrocarbon signal increased. One-dimensional NMR diffusion sequencing spectra of hydrogenated butyronitrile (HNMR) were also observed. Figure 3 and Figure 5 Compared to ordinary one-dimensional proton spectrum ( Figure 2 and Figure 4 The only difference is the lack of interference from the solvent signal. All the signals of hydrogenated butyronitrile are assigned in the same way as the 1H NMR spectrum, and the hydrogenation rate is calculated in the same way as the 1H NMR spectrum.
[0046] First, determine the formula for calculating the hydrogenation rate: Hydrogenation rate (%) = (Double bond content before hydrogenation - Double bond content after hydrogenation) / Double bond content before hydrogenation. Since the initial butadiene structure has two different addition mechanisms, 1,2 and 1,4, the butadiene in the butadiene-acrylonitrile structure before and after hydrogenation has two different olefin structures. The hydrogenation rate (%) can be more specifically expressed as (1,2-butadiene content before hydrogenation + 1,4-butadiene content - 1,2-butadiene content after hydrogenation - 1,4-double bond content after hydrogenation) / (1,2-double bond content before hydrogenation + 1,4-double bond content before hydrogenation).
[0047] Derivation and calculation process of the hydrogenation rate formula:
[0048] The degree of hydrogenation in this invention is calculated using a relative method, requiring no additional internal standard. The hydrogenation process involves only the conversion of olefins to alkanes. During the reaction, the molar ratio of the sum of unhydrogenated and hydrogenated olefins to the acrylonitrile component remains constant, and the proportions of each component (the sum of unhydrogenated and hydrogenated 1,2-butadiene, the sum of unhydrogenated and hydrogenated 1,4-butadiene, and acrylonitrile) relative to the saturated alkyl signal after complete hydrogenation are fixed. Therefore, knowing the proportions of each component in the butyronitrile feedstock before hydrogenation, combined with the integral value of the one-dimensional nuclear magnetic resonance diffusion ordering spectrum, allows for the establishment of an equation to calculate the hydrogenation rate.
[0049] First, the information of each component of the nitrile butadiene feedstock was obtained by 1H NMR spectroscopy. The molar concentrations of each component in the nitrile butadiene feedstock are as follows: acrylonitrile content C(ACN) = a; 1,4-butadiene content C(1,4-butadiene) = b; 1,2-butadiene content C(1,2-butadiene) = c;
[0050] The chemical shift and integrated area of hydrogenated butadiene nitrile can be obtained by testing one-dimensional nuclear magnetic resonance diffusion ordering spectra. The integrated area of the saturated aliphatic hydrocarbon signal (0.5–3.2 ppm) is: In(alkyl) = d; the integrated area of the 1,4-butadiene (CH=CH) and 1,2-butadiene (CH=) signals (5.2–5.8 ppm) is: In(1,2-butadiene) = e; and the integrated area of the 1,2-butadiene (CH2=) signal (4.8–5.2 ppm) is: In(1,2-butadiene) = f.
[0051] The ratio of the number of 1,4-butadiene before hydrogenation to the number of saturated hydrogens after complete hydrogenation = b / (3a+8b+8c);
[0052] The ratio of the number of 1,2-butadiene before hydrogenation to the number of saturated hydrogens after complete hydrogenation = c / (3a+8b+8c);
[0053] The ratio of the number of saturated hydrogen atoms in hydrogenated 1,4-butadiene to the number of saturated hydrogen atoms after complete hydrogenation = [(e-1 / 2f) / 2] / [(e-1 / 2f)*2+f / 2*5+d] = (e-1 / 2f) / (4e+3f+2d);
[0054] The ratio of the number of saturated hydrogen atoms in hydrogenated 1,2-butadiene to the number of saturated hydrogen atoms after complete hydrogenation = (f / 2) / [(e-1 / 2f)*2+f / 2*5+d] = f / (4e+3f+2d);
[0055] 1,4-Butadiene hydrogenation rate (1,4-HD) = [b / (3a+8b+8c)-(e-1 / 2f) / (4e+3f+2d)] / [b / (3a+8b+8c)] = 1-(e-1 / 2f)*(3a+8b+8c) / [b*(4e+3f+2d)];
[0056] 1,2-Butadiene hydrogenation rate (1,2-HD) = [c / (3a+8b+8c)-f / (4e+3f+2d)] / [c / (3a+8b+8c)] = 1-f*(3a+8b+8c) / [c*(4e+3f+2d)];
[0057] Butadiene hydrogenation rate (HD) = (content of 1,2-butadiene double bonds before hydrogenation + content of 1,4-butadiene - content of 1,2-butadiene after hydrogenation - content of 1,4 double bonds after hydrogenation) / (content of 1,2 double bonds before hydrogenation + content of 1,4 double bonds before hydrogenation) = (hydrogenated 1,4-butadiene + hydrogenated 1,2-butadiene) / (content of 1,4-butadiene before hydrogenation + content of 1,2-butadiene before hydrogenation) = [b / (3a+8b+8c)+c / (3a+8b+8c)-(e-1 / 2f) / (4e+3f+2d)-f / (4e+3f+2d)] / [b / (3 a+8b+8c)+c / (3a+8b+8c)]=1-[(e+1 / 2f)*(3a+8b+8c)] / [(4e+3f+2d)*(b+c)].
[0058] Compared with the prior art, the present invention has the following beneficial effects:
[0059] 1) The analytical method for determining the hydrogenation rate of hydrogenated butyronitrile provided by this invention is a rapid NMR analysis method for detecting the hydrogenation rate of hydrogenated butyronitrile in solution. This method can directly test the hydrogenation rate of hydrogenated butyronitrile containing solvent and perform quantitative analysis. It can quickly and accurately determine the hydrogenation rate of olefins in the reaction system in one step. In addition, this method has the advantages of not requiring sample pretreatment, simple operation steps, low cost, high efficiency, convenience, environmental friendliness, and reliability.
[0060] 2) The present invention provides an analytical method for determining the hydrogenation rate of hydrogenated butyronitrile, which uses a one-dimensional pulse gradient spin echo sequence NMR signal collection method. The sample does not require any pretreatment and the hydrogenation rate of hydrogenated butyronitrile in solution can be directly tested.
[0061] 3) This invention provides an analytical method for determining the hydrogenation rate of hydrogenated nitrile butadiene, offering a rapid and accurate method for quantitatively detecting the hydrogenation rate of hydrogenated nitrile butadiene samples. It primarily addresses the problem of hydrogenation rate testing in the R&D and production process by using one-dimensional nuclear magnetic resonance diffusion sequencing spectroscopy for hydrogenation rate testing. This method effectively overcomes the limitations of traditional infrared and nuclear magnetic resonance (NMR) spectroscopy methods, which require solvent removal before testing. The advantage of this method is that it allows direct testing of the reaction solution without the need for solvent removal. It can also calculate and distinguish the hydrogenation rates of 1,4-butadiene, 1,2-butadiene, and total butadiene, making it suitable for rapidly monitoring the hydrogenation process. The detection sensitivity is comparable to that of the NMR spectroscopy spectrum. Compared to mainstream infrared and NMR spectroscopy quantitative methods, which require solvent removal and sample reprocessing, this method eliminates the need for any sample pretreatment, avoiding potential cross-linking issues during solvent removal that could lead to sample insolubility and reducing the pretreatment process. The one-dimensional nuclear magnetic resonance diffusion ordering spectrum can be used for 60MHz low-field NMR. Because the low-field NMR has built-in deuterated reagents, the sample solution can be directly taken for testing, and the costs in terms of time, economy, manpower and environment are effectively controlled. Attached Figure Description
[0062] Figure 1 The 1H NMR spectrum (600MHz) of the solvent-free hydrogenated nitrile butadiene sample in the examples is shown.
[0063] Figure 2 The 1H NMR spectrum (600MHz) of the hydrogenated nitrile butadiene sample containing solvent in the examples is shown.
[0064] Figure 3 The image shows a one-dimensional nuclear magnetic resonance diffusion ordering spectrum (600 MHz) of a hydrogenated nitrile butadiene sample containing solvent in the examples.
[0065] Figure 4 The 1H NMR spectrum (60MHz) of the hydrogenated nitrile butadiene sample containing solvent in the examples is shown.
[0066] Figure 5 The image shows a one-dimensional nuclear magnetic resonance diffusion ordering spectrum (60 MHz) of a hydrogenated nitrile butadiene sample containing solvent in the examples. Detailed Implementation
[0067] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.
[0068] In the specification and claims, the terms "including" and "comprising" should be understood as "including, but not limited to". The specific details disclosed are for the purpose of making the present invention easier to understand. Those skilled in the art who implement this solution using one or more technical details are also considered to be implementing the technical solution of the present invention.
[0069] Unless otherwise specified in this invention, the component model, material name, connection structure, control method, and other features are considered to be common technical features disclosed in the prior art.
[0070] Table 1 shows a list of chemicals involved in the examples. The virgin nitrile rubber was purchased from PetroChina Lanzhou Petrochemical Product No. 3306G.
[0071] Table 1 List of chemicals involved in the experiment
[0072] chemicals Detailed Categories Acquisition methods deuterated chloroform Purity greater than 99.7% Cambridge Hydrogenated nitrile butadiene sample R&D products Lab-made
[0073] In the following examples, the hydrogenated nitrile rubber samples were obtained by catalytic hydrogenation of the original nitrile rubber. The catalytic hydrogenation was carried out using conventional catalytic hydrogenation methods. The catalytic hydrogenation method does not affect the determination of the hydrogenation rate of hydrogenated nitrile rubber. For reference, please refer to Wang Yang, Peng Xiaohong. Catalytic hydrogenation reaction of nitrile rubber [J]. Synthetic Rubber Industry, 2011, 34(6):3.DOI:10.3969 / j.issn.1000-1255.2011.06.002.
[0074] In the following examples, the component information of the nitrile butadiene raw material was obtained by 1H NMR spectroscopy. The instrument used for 1H NMR spectroscopy was a 60MHz or 600MHz NMR spectrometer. The 1H NMR spectrum (600MHz) of the solvent-free hydrogenated nitrile butadiene sample is shown below. Figure 1 The 1H NMR spectra (600MHz) of the hydrogenated nitrile butyrate sample containing solvent and the 1H NMR spectra (60MHz) of the hydrogenated nitrile butyrate sample containing solvent are shown below. Figure 2 , 4 .
[0075] In the following examples, firstly, the information of each component of the nitrile butadiene feedstock was obtained by 1H NMR spectroscopy. The molar concentrations of each component in the nitrile butadiene feedstock were as follows: acrylonitrile content C(ACN) = a; 1,4-butadiene content C(1,4-butadiene) = b; 1,2-butadiene content C(1,2-butadiene) = c. The chemical shifts and integrated areas of the hydrogenated nitrile butadiene were obtained by testing the one-dimensional NMR diffusion ordering spectrum. The integrated area of the saturated aliphatic hydrocarbon signal (0.5–3.2 ppm): In(alkyl) = d; the integrated area of the 1,4-butadiene (CH=CH) and 1,2-butadiene (CH=) signals (5.2–5.8 ppm): In(1,2-butadiene) = e; the integrated area of the 1,2-butadiene (CH2=) signal (4.8–5.2 ppm): In(1,2-butadiene) = f.
[0076] In the following examples, the hydrogenation rate was calculated using the following formula:
[0077] 1,4-Butadiene hydrogenation rate (1,4-HD) = [b / (3a+8b+8c)-(e-1 / 2f) / (4e+3f+2d)] / [b / (3a+8b+8c)] = 1-(e-1 / 2f)*(3a+8b+8c) / [b*(4e+3f+2d)].
[0078] 1,2-Butadiene hydrogenation rate (1,2-HD) = [c / (3a+8b+8c)-f / (4e+3f+2d)] / [c / (3a+8b+8c)] = 1-f*(3a+8b+8c) / [c*(4e+3f+2d)].
[0079] Butadiene hydrogenation rate (HD) = (content of 1,2-butadiene double bonds before hydrogenation + content of 1,4-butadiene - content of 1,2-butadiene after hydrogenation - content of 1,4 double bonds after hydrogenation) / (content of 1,2 double bonds before hydrogenation + content of 1,4 double bonds before hydrogenation) = (hydrogenated 1,4-butadiene + hydrogenated 1,2-butadiene) / (content of 1,4-butadiene before hydrogenation + content of 1,2-butadiene before hydrogenation) = [b / (3a+8b+8c)+c / (3a+8b+8c)-(e-1 / 2f) / (4e+3f+2d)-f / (4e+3f+2d)] / [b / (3 a+8b+8c)+c / (3a+8b+8c)]=1-[(e+1 / 2f)*(3a+8b+8c)] / [(4e+3f+2d)*(b+c)].
[0080] Example 1
[0081] The molar proportions of each component in the original nitrile butadiene rubber (nitrile butadiene raw material) were as follows: the contents of acrylonitrile, 1,2-butadiene and 1,4-butadiene were 34.5%, 58.8% and 6.7% respectively. After being dissolved in chlorobenzene solvent and subjected to catalytic hydrogenation, hydrogenated nitrile butadiene samples were obtained, and the degree of hydrogenation was tested.
[0082] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0083] Testing instrument: Oxford Pulse 60MHz nuclear magnetic resonance spectrometer, probe HX, Z gradient field intensity 0.5T / m.
[0084] Take approximately 0.6 ml of the catalytically hydrogenated sample solution (hydrogenated nitrile butadiene sample containing solvent) and transfer it to a 5 mm NMR tube. Select J-PESE (one-dimensional diffusion ordering spectroscopy) experiment. The number of acquisitions (scans) is NS = 16, the diffusion time Δ(D74) = 12000 μs, the gradient length D70 + D71 = 4.5 ms, and the gradient field ratio (percentage of maximum gradient field intensity) G1 = 0.8. The one-dimensional NMR diffusion ordering spectrum is obtained, as shown below. Figure 3 As shown, after the data acquisition is completed, the phase is corrected, the baseline is calibrated, and the hydrogenation rate is calculated by integration.
[0085] Example 2
[0086] The molar proportions of each component in the original nitrile rubber were as follows: acrylonitrile, 1,2-butadiene, and 1,4-butadiene were 34.5%, 58.8%, and 6.7%, respectively. The components were dissolved in chlorobenzene solvent, and the degree of hydrogenation was tested after catalytic hydrogenation.
[0087] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0088] Testing instrument: Bruker 600MHz nuclear magnetic resonance spectrometer, probe is BBFO (BBFO SMART ultrasensitive broadband probe), Z gradient field intensity 0.5T / m.
[0089] Take approximately 0.2 ml of the catalytically hydrogenated sample solution (hydrogenated nitrile butadiene sample containing solvent) and transfer it to a 5 mm NMR tube. Add approximately 0.5 ml of deuterated chloroform. Set the sampling parameters as follows: pulse sequence = ledbpgp2s1d (one-dimensional diffusion ordering spectrum), number of scans NS = 16, diffusion time Δ(p30) = 1200 μs, gradient length δ(d20) = 0.05 s, gradient field percentage (percentage of maximum gradient field intensity) GPZ6 = 95%. Obtain the one-dimensional NMR diffusion ordering spectrum, as shown below. Figure 5 As shown, after the data acquisition is completed, the phase is corrected, the baseline is calibrated, and the hydrogenation rate is calculated by integration.
[0090] Example 3
[0091] The molar proportions of each component in the original nitrile rubber were as follows: acrylonitrile, 1,2-butadiene, and 1,4-butadiene were 34.5%, 58.8%, and 6.7%, respectively. The components were dissolved in chlorobenzene solvent, and the degree of hydrogenation was tested after catalytic hydrogenation.
[0092] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0093] Testing instrument: Oxford Pulse 60MHz nuclear magnetic resonance spectrometer, probe HX, Z gradient field intensity 0.5T / m.
[0094] Take approximately 0.6 ml of the sample solution after catalytic hydrogenation (hydrogenated nitrile butadiene sample containing solvent) and transfer it to a 5 mm NMR tube. Select J-PESE (one-dimensional diffusion ordering spectrum) experiment, with NS = 16 acquisitions (scans), diffusion time Δ(D74) = 12000 μs, gradient length D70 + D71 = 4.5 ms, and gradient field ratio G1 (percentage of maximum gradient field intensity) = 0.8. After data acquisition, correct the phase, calibrate the baseline, and integrate to calculate the hydrogenation rate.
[0095] Example 4
[0096] The molar proportions of each component in the original nitrile rubber were as follows: acrylonitrile, 1,2-butadiene, and 1,4-butadiene were 34.5%, 58.8%, and 6.7%, respectively. The components were dissolved in chlorobenzene solvent, and the degree of hydrogenation was tested after catalytic hydrogenation.
[0097] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0098] Testing instrument: Bruker 600MHz nuclear magnetic resonance spectrometer, BBFO probe, Z gradient field intensity 0.5T / m.
[0099] Take approximately 0.2 ml of the catalytically hydrogenated sample solution (hydrogenated nitrile butadiene sample containing solvent) and transfer it to a 5 mm NMR tube. Add approximately 0.5 ml of deuterated chloroform. Set the sampling parameters as follows: pulse sequence = ledbpgp2s1d (one-dimensional diffusion ordering spectrum), number of scans NS = 16, diffusion time Δ(p30) = 1200 μs, gradient length δ(d20) = 0.05 s, and gradient field percentage (percentage of maximum gradient field intensity) GPZ6 = 95%. After data acquisition, correct the phase, calibrate the baseline, and integrate to calculate the hydrogenation rate.
[0100] Example 5
[0101] The molar proportions of each component in the original nitrile rubber were as follows: acrylonitrile, 1,2-butadiene, and 1,4-butadiene were 34.5%, 58.8%, and 6.7%, respectively. The components were dissolved in chlorobenzene solvent, and the degree of hydrogenation was tested after catalytic hydrogenation.
[0102] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0103] Testing instrument: Oxford Pulse 60MHz nuclear magnetic resonance spectrometer, probe HX, Z gradient field intensity 0.5T / m.
[0104] Take approximately 0.6 ml of the catalytically hydrogenated sample (hydrogenated nitrile butadiene sample containing solvent) solution and transfer it to a 5 mm NMR tube. Select J-PESE (one-dimensional diffusion ordering spectrum) experiment, with the number of acquisitions (scans) NS = 32, diffusion time Δ(D74) = 12000 μs, gradient length D70 + D71 = 4.5 ms, and gradient field ratio (percentage of maximum gradient field intensity) G1 = 0.8. After data acquisition, correct the phase, calibrate the baseline, and integrate to calculate the hydrogenation rate.
[0105] Example 6
[0106] The molar proportions of each component in the original nitrile rubber were as follows: acrylonitrile, 1,2-butadiene, and 1,4-butadiene were 34.5%, 58.8%, and 6.7%, respectively. The components were dissolved in chlorobenzene solvent, and the degree of hydrogenation was tested after catalytic hydrogenation.
[0107] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0108] Testing instrument: Bruker 600MHz nuclear magnetic resonance spectrometer, BBFO probe, Z gradient field intensity 0.5T / m.
[0109] Take approximately 0.2 ml of the catalytically hydrogenated sample solution (hydrogenated nitrile butadiene sample containing solvent) and transfer it to a 5 mm NMR tube. Add approximately 0.5 ml of deuterated chloroform. Set the sampling parameters as follows: pulse sequence = ledbpgp2s1d (one-dimensional diffusion ordering spectrum), number of scans NS = 8, diffusion time Δ(p30) = 1200 μs, gradient length δ(d20) = 0.05 s, gradient field percentage (percentage of maximum gradient field intensity) gpz6 = 95. After data acquisition, correct the phase, calibrate the baseline, and integrate to calculate the hydrogenation rate.
[0110] Example 7
[0111] The molar proportions of each component in the original nitrile rubber were as follows: acrylonitrile, 1,2-butadiene, and 1,4-butadiene were 34.5%, 58.8%, and 6.7%, respectively. The components were dissolved in chlorobenzene solvent, and the degree of hydrogenation was tested after catalytic hydrogenation.
[0112] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0113] Testing instrument: Oxford Pulse 60MHz nuclear magnetic resonance spectrometer, probe HX, Z gradient field intensity 0.5T / m.
[0114] Take approximately 0.6 ml of the catalytically hydrogenated sample (hydrogenated nitrile butadiene sample containing solvent) solution and transfer it to a 5 mm NMR tube. Select J-PESE (one-dimensional diffusion ordering spectrum) experiment, with the number of acquisitions (scans) NS = 32, diffusion time Δ(D74) = 12000 μs, gradient length D70 + D71 = 4.5 ms, and gradient field ratio (percentage of maximum gradient field intensity) G1 = 0.8. After data acquisition, correct the phase, calibrate the baseline, and integrate to calculate the hydrogenation rate.
[0115] Example 8
[0116] The molar proportions of each component in the original nitrile rubber were as follows: acrylonitrile, 1,2-butadiene, and 1,4-butadiene were 34.5%, 58.8%, and 6.7%, respectively. The components were dissolved in chlorobenzene solvent, and the degree of hydrogenation was tested after catalytic hydrogenation.
[0117] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0118] Testing instrument: Oxford Pulse 60MHz nuclear magnetic resonance spectrometer, probe HX, Z gradient field intensity 0.5T / m.
[0119] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0120] Take approximately 0.6 ml of the sample solution after catalytic hydrogenation (hydrogenated nitrile butadiene sample containing solvent) and transfer it to a 5 mm NMR tube. Select J-PESE (one-dimensional diffusion ordination spectroscopy) experiment, with NS = 16 acquisitions (scans), diffusion time Δ(D74) = 12000 μs, gradient length D70 + D71 = 4.5 ms, and gradient field ratio (percentage of maximum gradient field intensity) G1 = 0.8. After data acquisition, correct the phase, calibrate the baseline, and integrate to calculate the hydrogenation rate.
[0121] Example 9
[0122] The molar proportions of each component in the original nitrile rubber were as follows: acrylonitrile, 1,2-butadiene, and 1,4-butadiene were 34.5%, 58.8%, and 6.7%, respectively. The components were dissolved in chlorobenzene solvent, and the degree of hydrogenation was tested after catalytic hydrogenation.
[0123] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0124] Testing instrument: Oxford Pulse 60MHz nuclear magnetic resonance spectrometer, probe HX, Z gradient field intensity 0.5T / m.
[0125] Take approximately 0.6 ml of the sample solution after catalytic hydrogenation (hydrogenated nitrile butadiene sample containing solvent) and transfer it to a 5 mm NMR tube. Select J-PESE (one-dimensional diffusion ordering spectrum) experiment, with the number of acquisitions (scans) NS = 128, diffusion time Δ(D74) = 12000 μs, gradient length D70 + D71 = 4.5 ms, and gradient field ratio (percentage of maximum gradient field intensity) G1 = 0.8. After data acquisition, correct the phase, calibrate the baseline, and integrate to calculate the hydrogenation rate.
[0126] Example 10
[0127] The molar proportions of each component in the original nitrile rubber were as follows: acrylonitrile, 1,2-butadiene, and 1,4-butadiene were 34.5%, 58.8%, and 6.7%, respectively. The components were dissolved in chlorobenzene solvent, and the degree of hydrogenation was tested after catalytic hydrogenation.
[0128] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0129] Testing instrument: Oxford Pulse 60MHz nuclear magnetic resonance spectrometer, probe HX, Z gradient field intensity 0.5T / m.
[0130] Take approximately 0.6 ml of the sample solution after catalytic hydrogenation (hydrogenated nitrile butadiene sample containing solvent) and transfer it to a 5 mm NMR tube. Select J-PESE (one-dimensional diffusion ordering spectrum) experiment, with the number of acquisitions (scans) NS = 32, diffusion time Δ(D74) = 12000 μs, gradient length D70 + D71 = 4.5 ms, and gradient field ratio (percentage of maximum gradient field intensity) G1 = 1. After data acquisition, correct the phase, calibrate the baseline, and integrate to calculate the hydrogenation rate.
[0131] Example 11
[0132] The molar proportions of each component in the original nitrile rubber were as follows: acrylonitrile, 1,2-butadiene, and 1,4-butadiene were 34.5%, 58.8%, and 6.7%, respectively. The components were dissolved in chlorobenzene solvent, and the degree of hydrogenation was tested after catalytic hydrogenation.
[0133] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0134] Testing instrument: Oxford Pulse 60MHz nuclear magnetic resonance spectrometer, probe HX, Z gradient field intensity 0.5T / m.
[0135] Take approximately 0.6 ml of the sample solution after catalytic hydrogenation (hydrogenated nitrile butadiene sample containing solvent) and transfer it to a 5 mm NMR tube. Select J-PESE (one-dimensional diffusion ordination spectroscopy) experiment, with NS = 16 acquisitions (scans), diffusion time Δ(D74) = 15000 μs, gradient length D70 + D71 = 4.5 ms, and gradient field ratio (percentage of maximum gradient field intensity) G1 = 0.8. After data acquisition, correct the phase, calibrate the baseline, and integrate to calculate the hydrogenation rate.
[0136] Example 12
[0137] The molar proportions of each component in the original nitrile rubber were as follows: acrylonitrile, 1,2-butadiene, and 1,4-butadiene were 34.5%, 58.8%, and 6.7%, respectively. The components were dissolved in chlorobenzene solvent, and the degree of hydrogenation was tested after catalytic hydrogenation.
[0138] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0139] Testing instrument: Oxford Pulse 60MHz nuclear magnetic resonance spectrometer, probe HX, Z gradient field intensity 0.5T / m.
[0140] Take approximately 0.6 ml of the sample solution after catalytic hydrogenation (hydrogenated nitrile butadiene sample containing solvent) and transfer it to a 5 mm NMR tube. Select J-PESE (one-dimensional diffusion ordination spectroscopy) experiment, with NS = 16 acquisitions (scans), diffusion time Δ(D74) = 12000 μs, gradient length D70 + D71 = 4.5 ms, and gradient field ratio (percentage of maximum gradient field intensity) G1 = 0.8. After data acquisition, correct the phase, calibrate the baseline, and integrate to calculate the hydrogenation rate.
[0141] Example 13
[0142] The molar proportions of each component in the original nitrile rubber were as follows: acrylonitrile, 1,2-butadiene, and 1,4-butadiene were 34.5%, 58.8%, and 6.7%, respectively. The components were dissolved in chlorobenzene solvent, and the degree of hydrogenation was tested after catalytic hydrogenation.
[0143] This embodiment provides an analytical method for rapidly determining the hydrogenation rate of hydrogenated butyronitrile.
[0144] Testing instrument: Bruker 600MHz nuclear magnetic resonance spectrometer, BBFO probe, Z gradient field intensity 0.5T / m.
[0145] Take approximately 0.2 ml of the catalytically hydrogenated sample solution (hydrogenated nitrile butadiene sample containing solvent) and transfer it to a 5 mm NMR tube. Add approximately 0.5 ml of deuterated chloroform. Set the sampling parameters as follows: pulse sequence = ledbpgp2s1d (one-dimensional diffusion ordering spectrum), number of scans NS = 16, diffusion time Δ(p30) = 1200 μs, gradient length δ(d20) = 0.05 s, and gradient field percentage (percentage of maximum gradient field intensity) GPZ6 = 95%. After data acquisition, correct the phase, calibrate the baseline, and integrate to calculate the hydrogenation rate.
[0146] Comparison Example
[0147] This comparative example provides an analytical method for determining the hydrogenation rate of hydrogenated butyronitrile.
[0148] The 1H NMR spectra of the original nitrile butadiene rubber in Examples 1-13 and the samples after catalytic hydrogenation (solvent-free hydrogenated nitrile butadiene rubber samples) after solvent removal by drying were measured using a 600MHz nuclear magnetic resonance spectrometer and the 1H NMR method. The hydrogenation rate of the hydrogenated nitrile butadiene rubber was calculated.
[0149] The specific process of solvent removal by drying method: The reaction solution of hydrogenated nitrile butadiene is passed through an equal amount of ethanol for flocculation. After washing three times, a solid glue is obtained. The remaining solvent is removed by drying in a vacuum oven at 95 degrees Celsius for 24 hours, and the dried hydrogenated nitrile butadiene solid glue is obtained.
[0150] It should be noted that the reason why the hydrogenation rates are the same or different in Examples 1-13 is as follows: the catalytic hydrogenation reaction conditions in Examples 1 and 2 are the same; the catalytic hydrogenation reaction conditions in Examples 3 and 4 are the same but different from those in Example 1 (different catalysts); the catalytic hydrogenation reaction conditions in Examples 5 and 6 are the same but different from those in Example 1 (different catalysts); the catalytic hydrogenation reaction conditions in Example 7 are different from those in Example 1 (different catalysts); the catalytic hydrogenation reaction conditions in Example 8 are different from those in Example 1 (different catalysts); the catalytic hydrogenation reaction conditions in Examples 9, 10, 11, and 12 are the same but different from those in Example 1 (different catalysts); and the catalytic hydrogenation reaction conditions in Example 13 are different. Unlike Example 1 (different catalyst), the catalysts used in Examples 1-13 are all commercially available catalysts. The purpose of this invention is to provide an analytical method for determining the hydrogenation rate of hydrogenated butyronitrile without removing the solvent, which is rapid, reliable, safe, convenient, and accurate. This method is verified by comparing the results with 600MHz proton NMR spectroscopy. The reaction conditions of catalytic hydrogenation do not affect the implementation of the analytical method for determining the hydrogenation rate of hydrogenated butyronitrile. Different reaction conditions (different catalysts) are used to prepare different catalytic hydrogenation products. The purpose is to verify that the differences in acrylonitrile content, 1,4-butadiene content, and 1,2-butadiene content in the products do not affect the use of the analytical method for determining the hydrogenation rate of hydrogenated butyronitrile of this invention.
[0151] The results of tests 1-13 and the comparison results of 1H NMR spectrum are shown in Table 2.
[0152] Table 2 compares the hydrogenation degree test results of the examples with the hydrogenation rate results of the standard 600MHz proton spectrum.
[0153]
[0154] As shown in Table 2, the analytical method for determining the hydrogenation rate of hydrogenated butyronitrile using the present invention shows high consistency with the standard 600MHz proton spectrum hydrogenation rate results, with a deviation within 5%. Furthermore, the analytical method for determining the hydrogenation rate of hydrogenated butyronitrile using the present invention does not require solvent removal and is fast, reliable, safe, convenient, and accurate.
[0155] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.
Claims
1. An analytical method for determining the hydrogenation rate of hydrogenated butyronitrile, characterized in that, The analytical method for determining the hydrogenation rate of hydrogenated butyronitrile includes the following steps: S1. Use high-field NMR or low-field NMR to test the hydrogenated nitrile butadiene sample containing solvent, set the sampling parameters, and acquire a one-dimensional NMR diffusion ordering spectrum. S2. Obtain the chemical shift and integral area information of hydrogenated butyronitrile through one-dimensional nuclear magnetic resonance diffusion sorting spectrum, and calculate the hydrogenation rate by combining the butyronitrile raw material composition information. The hydrogenation rate is one or more of 1,4-butadiene hydrogenation rate, 1,2-butadiene hydrogenation rate, and butadiene hydrogenation rate. The composition information of the butadiene-nitrile raw material includes acrylonitrile content, 1,4-butadiene content, and 1,2-butadiene content; The chemical shift and integral area information corresponding to the hydrogenated butadiene nitrile includes the signal integral area of saturated aliphatic hydrocarbons, the CH=CH signal of 1,4-butadiene and the CH= signal integral area of 1,2-butadiene, and the CH2= signal integral area of 1,2-butadiene.
2. The analytical method for determining the hydrogenation rate of hydrogenated butyronitrile according to claim 1, characterized in that, In step S2, the hydrogenation rate of 1,4-butadiene is calculated using the following formula: 1,4-Butadiene hydrogenation rate = [b / (3a+8b+8c)-(e-1 / 2f) / (4e+3f+2d)] / [b / (3a+8b+8c)] = 1-(e-1 / 2f)*(3a+8b+8c) / [b*(4e+3f+2d)], In the formula, a = acrylonitrile content, b = 1,4-butadiene content, c = 1,2-butadiene content, d = signal integration area of saturated aliphatic hydrocarbons, e = signal integration area of 1,4-butadiene CH=CH and 1,2-butadiene CH= signal, and f = signal integration area of 1,2-butadiene CH2= signal.
3. The analytical method for determining the hydrogenation rate of hydrogenated butyronitrile according to claim 1, characterized in that, In step S2, the hydrogenation rate of 1,2-butadiene is calculated using the following formula: 1,2-Butadiene hydrogenation rate = [c / (3a+8b+8c)-f / (4e+3f+2d)] / [c / (3a+8b+8c)] = 1-f*(3a+8b+8c) / [c*(4e+3f+2d)], In the formula, a = acrylonitrile content, b = 1,4-butadiene content, c = 1,2-butadiene content, d = signal integration area of saturated aliphatic hydrocarbons, e = signal integration area of 1,4-butadiene CH=CH and 1,2-butadiene CH= signal, and f = signal integration area of 1,2-butadiene CH2= signal.
4. The analytical method for determining the hydrogenation rate of hydrogenated butyronitrile according to claim 1, characterized in that, In step S2, the butadiene hydrogenation rate is calculated using the following formula: Butadiene hydrogenation rate = (content of 1,2-butadiene double bonds before hydrogenation + content of 1,4-butadiene - content of 1,2-butadiene after hydrogenation - content of 1,4 double bonds after hydrogenation) / (content of 1,2 double bonds before hydrogenation + content of 1,4 double bonds before hydrogenation) = (hydrogenated 1,4-butadiene + hydrogenated 1,2-butadiene) / (content of 1,4-butadiene before hydrogenation + content of 1,2-butadiene before hydrogenation) = [b / (3a+8b+8c)+c / (3a+8b+8c)-(e-1 / 2f) / (4e+3f+2d)-f / (4e+3f+2d)] / [b / (3a +8b+8c)+c / (3a+8b+8c)]=1-[(e+1 / 2f)*(3a+8b+8c)] / [(4e+3f+2d)*(b+c)], In the formula, a = acrylonitrile content, b = 1,4-butadiene content, c = 1,2-butadiene content, d = signal integration area of saturated aliphatic hydrocarbons, e = signal integration area of 1,4-butadiene CH=CH and 1,2-butadiene CH= signal, and f = signal integration area of 1,2-butadiene CH2= signal.
5. The analytical method for determining the hydrogenation rate of hydrogenated butyronitrile according to claim 1, characterized in that, In step S1, when using high-field NMR, step S1 includes the following sub-steps: A hydrogenated nitrile butyrate sample containing solvent was directly added to an NMR tube, followed by the addition of deuterated chloroform. The ledbpgp2s1d pulse sequence was selected, and the sampling parameters were set as follows: scan number 8–256, diffusion time Δ(P30) = 1000 μs–2500 μs, and the percentage of maximum gradient field intensity GPZ6 = 35%–100%. One-dimensional NMR diffusion ordering spectra were then acquired.
6. The analytical method for determining the hydrogenation rate of hydrogenated butyronitrile according to claim 5, characterized in that, The number of scans was 16, the diffusion time Δ(P30) = 1200 μs, and the percentage of maximum gradient field intensity GPZ6 = 95%.
7. The analytical method for determining the hydrogenation rate of hydrogenated butyronitrile according to claim 1, characterized in that, In step S1, when using low-field NMR, step S1 includes the following sub-steps: A sample of hydrogenated nitrile butadiene containing solvent was directly added to an NMR tube. J-PGSE was selected for testing. The sampling parameters were set as follows: number of scans 8–256, diffusion time Δ(D74) = 10000–30000 μs, percentage of maximum gradient field intensity G1 = 0.3–1, and a one-dimensional NMR diffusion ordering spectrum was acquired.
8. The analytical method for determining the hydrogenation rate of hydrogenated butyronitrile according to claim 7, characterized in that, The number of scans was 32, the diffusion time Δ(D74) = 12000μs, and the percentage of the maximum gradient field intensity G1 = 0.
8.
9. The analytical method for determining the hydrogenation rate of hydrogenated butyronitrile according to claim 1, characterized in that, The high-field NMR is a 600MHz high-field NMR; The low-field NMR is a 60MHz low-field NMR.
10. The analytical method for determining the hydrogenation rate of hydrogenated butyronitrile according to claim 1, characterized in that, In step S2, the hydrogen spectrum signal of the butyronitrile raw material is assigned using one-dimensional nuclear magnetic resonance hydrogen spectroscopy. The signals for saturated aliphatic hydrocarbons are 0.5–3 ppm, the signal for 1,2-butadiene CH2= is 4.8–5.2 ppm, and the signals for 1,4-butadiene CH=CH and 1,2-butadiene CH= are 5.2–5.8 ppm.