CN114262281B - Separation method of pyrazoline isomer mixture by using polar solvent-resistant nanofiltration membrane - Google Patents
Separation method of pyrazoline isomer mixture by using polar solvent-resistant nanofiltration membrane Download PDFInfo
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- CN114262281B CN114262281B CN202111563909.4A CN202111563909A CN114262281B CN 114262281 B CN114262281 B CN 114262281B CN 202111563909 A CN202111563909 A CN 202111563909A CN 114262281 B CN114262281 B CN 114262281B
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Abstract
The invention discloses a separation method of a pyrazoline isomer mixture by using a polar solvent-resistant nanofiltration membrane, which comprises the following steps: (1) Sealing and fixing the polar solvent-resistant nanofiltration membrane in a membrane assembly, and maintaining the constant temperature by using a heat conductor; (2) Pressurizing raw materials by a pump, and circulating concentrated solution to a raw material tank by adopting a cross-flow mode through a membrane assembly to realize enrichment of pyrazoline; and detecting the concentration of the components in the raw material tank in an offline gas phase mode every 0.5h, and separating to reach an end point when the concentration is no longer changed. Aiming at the problems that the boiling points of pyrazoline isomers are similar, the structure is unstable, the traditional industrial rectification is difficult to realize separation and the like, the invention provides a high-efficiency polar solvent-resistant nanofiltration membrane separation method by combining the dynamic diameter and polarity difference of the isomers. Meanwhile, the method has simple process and low energy consumption, and has important significance for separating isomers in the pharmaceutical and chemical industry.
Description
Technical Field
The invention belongs to the field of chemical separation, and particularly relates to a separation method of a pyrazoline isomer mixture by using a polar solvent-resistant nanofiltration membrane.
Technical Field
Hydrocarbon (hydrocarbon) fuels are the most widely used and most energy-consuming sources in the world transportation field, and are all occupied in aerospace, land transportation, marine transportation and military industriesTreating the disease. It is generally believed that the compounds have a number of carbon atoms greater than 7 (C 7 ) Is commonly referred to as a high carbon number hydrocarbon fuel. Liquid hydrocarbon fuels are a wide variety of sources and are easy to transport, and for a long time in the future, hydrocarbon fuels remain an irreplaceable primary energy source. The high-tension annular hydrocarbon fuel is a novel hydrocarbon high-energy fuel, and the molecular structure of the high-tension annular hydrocarbon fuel takes tension rings including cyclopropane as a structural main body, so that the high-tension annular hydrocarbon fuel has high tension energy and very excellent combustion performance. Pyrazoline is an important intermediate product for preparing high-energy tension ring fuel, and has strong heat sensitivity and instability. Currently, pyrazolines are mainly obtained from acid catalyzed isomerization of ketazine. However, the ketazine and the pyrazoline are isomers with similar boiling points, and the traditional distillation method has huge energy consumption and hardly achieves the expected separation effect, and more importantly, greatly reduces the yield of the high-energy tension ring prepared by the denitrification of the pyrazoline. The separation of pyrazoline with high purity and the exploration of new separation methods are the problems to be solved urgently.
The membrane separation technology does not involve phase change in the process of separating substances, has low energy requirement, has the cost about one third of that of the traditional rectification separation, has milder membrane separation condition, selective permeability and is suitable for a separation system with complex heat-sensitive substances, and the two factors lead the membrane separation to be applied more and more widely in the biochemical field.
Through simulation calculation, pyrazoline and ketazine are shown to be isomers, but have obvious differences in molecular dynamics diameter and molecular polarity, so that the membrane separation technology is considered to be an effective and feasible separation mode for the ketazine and pyrazoline mixed solution by combining with the membrane separation mechanism and property. In addition, the pyrazoline isomer mixture has a corrosion effect on the membrane, so a solvent-resistant polar nanofiltration membrane is required.
Disclosure of Invention
Aiming at the practical dilemma of separating and purifying the pyrazoline isomer mixture, and combining simulation data, the invention discovers that the dynamic diameter and the molecular polarity between the pyrazoline and the isomer have obvious differences, so the invention provides a method for separating the pyrazoline isomer mixture by using a polar solvent-resistant nanofiltration membrane, which provides a feasible path for separating the isomers in the pharmaceutical and chemical fields.
In order to solve the technical problems, the invention adopts the following technical scheme:
a method for separating pyrazoline isomer mixture by using a polar solvent-resistant nanofiltration membrane comprises the following steps:
(1) Sealing and fixing the polar solvent-resistant nanofiltration membrane in a membrane assembly, and maintaining the constant temperature by using a heat conductor;
(2) The raw materials are pressurized by a pump, a cross flow mode is adopted to pass through a membrane assembly, a ketone nitrogen solution containing a small amount of pyrazoline flows out from a membrane side port in a permeation measurement way, a concentrated solution containing pyrazoline and ketone nitrogen flows out from an outlet end of the membrane assembly and circulates to a raw material tank, so that enrichment of the pyrazoline is realized, components on the membrane permeation side are collected, the concentration of the components in the raw material tank is detected in an offline gas phase every 0.5h, and when the concentration is not changed, the separation reaches a terminal point.
Further, the polar solvent-resistant nanofiltration membrane in the step (1) is any one of a modified polyimide solvent-resistant membrane or a modified polyacrylonitrile solvent-resistant membrane, and the molecular weight cut-off is 50-150Da.
Further, the polar solvent-resistant nanofiltration membrane in the step (1) is an asymmetric nanocomposite membrane, and the effective thickness of the membrane layer is 0.5-80 mu m.
Further, the temperature range of the heat conductor in the step (1) is controlled to be 10-60 ℃.
Further, the raw materials in the step (2) are pyrazoline isomer mixtures, specifically any one of acetone ketazine/3, 5-trimethyl-2-pyrazoline, 2-Ding Tongtong ketazine/3, 5-diethyl-5-methyl-2-pyrazoline, 2-pentanone ketazine/3, 5-dipropyl-5-methyl-2-pyrazoline, methyl isopropyl ketazine/3, 5-diisopropyl-5-methyl-2-pyrazoline, 2-hexanone ketazine/3, 5-dibutyl-5-methyl-2-pyrazoline and cyclopropyl ketazine/5-methyl-3, 5-dicyclohexylpyrazoline mixtures, wherein the mass concentration ratio of the pyrazoline to the ketazine is (0.001-0.15): 1.
Further, the pyrazoline isomer mixture temperature in the step (2) is 25-50 ℃, preferably 25 ℃; the membrane operating pressure is 20-40bar, preferably 40bar; and (5) cross-flow filtering in an operation mode.
Further, the off-line gas phase detection in the step (2) adopts a chromatographic column: HP-5 nonpolar column; column temperature procedure: maintaining at 50deg.C for 1min, heating to 120deg.C at 10deg.C/min for 1min, and heating to 280 deg.C at 15deg.C/min for 9min; sample inlet temperature: 300 ℃; split ratio: 100:1; control mode: chromatographic column flow.
The beneficial effects of the invention are as follows: the invention is based on the obvious difference of dynamic diameters and molecular polarities between pyrazoline and isomers, and realizes the efficient separation of the pyrazoline isomer mixture by utilizing the steric effect and the electrostatic effect (hydrogen bond is formed between the pyrazoline and a membrane surface material) of the solvent-resistant nanofiltration membrane, thereby effectively solving the problems of high energy consumption and heat sensitivity of the pyrazoline in the traditional rectification separation mode and solving the problems of heat sensitivity of the pyrazoline in the rectification process. At the same time, the method provides a feasible path for separating isomers in the pharmaceutical and chemical field.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a pyrazoline isomerism mixture liquid film separation device;
FIG. 2 is a graph showing the solvent resistance test (one week immersion) of the modified polyacrylonitrile solvent resistant film of example 1;
FIG. 3 is a graph of the solvent resistance test (one week soak) of the modified polyimide solvent resistant film of example 2;
FIG. 4 is a graph showing the solvent resistance test (one week soaking) of the modified polyacrylonitrile solvent resistant film of example 3.
Detailed Description
Embodiments of the present invention will be further described with reference to the accompanying drawings and examples. It is to be understood that the following examples are intended to illustrate the present invention and are not to be construed as limiting the scope of the invention, and that numerous insubstantial modifications and adaptations can be made by those skilled in the art in light of the foregoing disclosure.
The separation coefficient calculation formula:
the molecular kinetic diameters of ketazine and pyrazoline are shown in Table 1.
TABLE 1 Keto-nitrogen and pyrazoline molecular dynamics diameter Table
Example 1
The separation method of the pyrazoline isomer mixture by using the separation device shown in fig. 1 and using the polar solvent-resistant nanofiltration membrane in the embodiment comprises the following steps:
(1) The membrane device pressure was set at 20bar and the temperature 25 ℃. The raw material liquid is a mixed liquid of acetone ketazine and 3, 5-trimethyl-2-pyrazoline, and the mass concentration ratio of the pyrazoline to the ketazine is 0.15:1.
(2) The raw material liquid is added into a material tank, pumped in by a pump, enters from an inlet section of a membrane assembly, is separated by a modified polyacrylonitrile membrane (GC-PANS solvent-resistant membrane, national and technology Co., ltd.), and concentrated solution containing pyrazoline and ketazine flows out from an outlet end of the membrane assembly and then is circulated to the raw material tank, and ketazine solution containing a small amount of pyrazoline flows out from a permeation side of a side opening of the membrane. And detecting the concentration of the components in the raw material tank in an offline gas phase mode every 0.5h, and separating to reach an end point when the concentration is no longer changed.
GC detection is carried out on the raw material liquid and the solution at the permeation side respectively, and chromatographic columns are adopted for off-line gas phase detection: HP-5 nonpolar column; column temperature procedure: maintaining at 50deg.C for 1min, heating to 120deg.C at 10deg.C/min for 1min, and heating to 280 deg.C at 15deg.C/min for 9min; sample inlet temperature: 300 ℃; split ratio: 100:1; control mode: chromatographic column flow. The separation coefficient was calculated as shown in the following table.
Example 2
The separation method of the pyrazoline isomer mixture by using the separation device shown in fig. 1 and using the polar solvent-resistant nanofiltration membrane in the embodiment comprises the following steps:
(1) The membrane device pressure was set at 30bar and the temperature 25 ℃. The raw material liquid is a mixed liquid of 2-Ding Tongtong continuous nitrogen and 3, 5-diethyl-5-methyl-2-pyrazoline, and the mass concentration ratio of the pyrazoline to the ketazine is 0.05:1.
(2) Adding raw material liquid into a material tank, pumping the raw material liquid into the material tank through a pump, entering the material tank from an inlet section of a membrane assembly, separating the raw material liquid by a modified polyacrylonitrile membrane (GC-PANS solvent-resistant membrane, national and technology Co., ltd.), and circulating the concentrated solution containing pyrazoline and ketazine to the raw material tank after the concentrated solution containing a small amount of pyrazoline flows out from an outlet end of the membrane assembly and flows out from a permeation side of a side opening of the membrane; and detecting the concentration of the components in the raw material tank in an offline gas phase mode every 0.5h, and separating to reach an end point when the concentration is no longer changed.
GC detection is carried out on the raw material liquid and the solution at the permeation side respectively, and chromatographic columns are adopted for off-line gas phase detection: HP-5 nonpolar column; column temperature procedure: maintaining at 50deg.C for 1min, heating to 120deg.C at 10deg.C/min for 1min, and heating to 280 deg.C at 15deg.C/min for 9min; sample inlet temperature: 300 ℃; split ratio: 100:1; control mode: chromatographic column flow. The separation coefficient was calculated as shown in the following table.
Example 3
The separation method of the pyrazoline isomer mixture by using the separation device shown in fig. 1 and using the polar solvent-resistant nanofiltration membrane in the embodiment comprises the following steps:
(1) The membrane device pressure was set at 40bar and the temperature 25 ℃. The raw material liquid is a mixed liquid of cyclopropyl ketazine and 5-methyl-3, 5-dicyclohexyl pyrazoline, and the mass concentration ratio of the pyrazoline to the ketazine is 0.03:1.
(2) The raw material liquid is added into a material tank, pumped in by a pump, enters from an inlet section of a membrane assembly, is separated by a modified polyimide membrane (GC-PANS solvent-resistant membrane, national and technology Co., ltd.), and concentrated solution containing pyrazoline and ketazine flows out from an outlet end of the membrane assembly and then circulates to the material tank, a ketazine solution containing a small amount of pyrazoline flows out from a permeation side of a side opening of the membrane, the concentration of components in the material tank is detected offline gas phase every 0.5h, and when the concentration is no longer changed, the separation reaches an end point.
GC detection is carried out on the raw material liquid and the solution at the permeation side respectively, and chromatographic columns are adopted for off-line gas phase detection: HP-5 nonpolar column; column temperature procedure: maintaining at 50deg.C for 1min, heating to 120deg.C at 10deg.C/min for 1min, and heating to 280 deg.C at 15deg.C/min for 9min; sample inlet temperature: 300 ℃; split ratio: 100:1; control mode: chromatographic column flow. The separation coefficient was calculated as shown in the following table.
Analysis of all the above data showed that: the modified polyacrylonitrile membrane can be used for separating ketazine from pyrazoline, and has remarkable separation effect.
Figures 2-4 are test pictures of a film immersed in a pyrazolone nitrogen mixture for one week, demonstrating that the film can be used normally in this environment.
The foregoing has shown and described the basic principles and main features of the present invention and the advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (7)
1. A method for separating a pyrazoline isomer mixture by using a polar solvent-resistant nanofiltration membrane, which is characterized by comprising the following steps:
(1) Sealing and fixing the polar solvent-resistant nanofiltration membrane in a membrane assembly, and maintaining the constant temperature by using a heat conductor;
(2) Pressurizing the pyrazoline isomer mixture by a pump, allowing the mixture to pass through a membrane assembly in a cross-flow mode, allowing a ketone nitrogen solution containing a small amount of pyrazoline to flow out from a membrane side port in a permeation measurement way, allowing a concentrated solution containing pyrazoline and ketone nitrogen to flow out from an outlet end of the membrane assembly and circulate to a raw material tank, thus realizing enrichment of the pyrazoline, detecting the concentration of components in the raw material tank in an offline gas phase every 0.5h, and separating to reach a terminal point when the concentration is no longer changed;
the polar solvent-resistant nanofiltration membrane in the step (1) is any one of a modified polyimide solvent-resistant membrane or a modified polyacrylonitrile solvent-resistant membrane, and the molecular weight cut-off is 50-150Da.
2. The method for separating pyrazoline isomer mixture by using the polar solvent resistant nanofiltration membrane according to claim 1, wherein the method comprises the following steps: the polar solvent-resistant nanofiltration membrane in the step (1) is an asymmetric nanocomposite membrane, and the effective thickness of the membrane layer is 0.5-80 mu m.
3. The method for separating pyrazoline isomer mixture by using the polar solvent resistant nanofiltration membrane according to claim 1, wherein the method comprises the following steps: the temperature range of the heat conductor in the step (1) is controlled to be 10-60 ℃.
4. The method for separating pyrazoline isomer mixture by using the polar solvent resistant nanofiltration membrane according to claim 1, wherein the method comprises the following steps: the pyrazoline isomer mixture in the step (2) is a mixture of pyrazoline and ketazine.
5. The method for separating pyrazoline isomer mixture by using the polar solvent resistant nanofiltration membrane according to claim 4, wherein the method comprises the following steps: the mass concentration ratio of pyrazoline to ketazine is (0.001-0.15): 1.
6. The method for separating pyrazoline isomer mixture by using the polar solvent resistant nanofiltration membrane according to claim 4 or 5, wherein the method comprises the following steps: the pyrazoline and ketone nitrogen mixture is any one of acetone ketone nitrogen/3, 5-trimethyl-2-pyrazoline, 2-Ding Tongtong nitrogen/3, 5-diethyl-5-methyl-2-pyrazoline, 2-pentanone nitrogen/3, 5-dipropyl-5-methyl-2-pyrazoline, methyl isopropyl ketone nitrogen/3, 5-diisopropyl-5-methyl-2-pyrazoline, 2-hexanone nitrogen/3, 5-dibutyl-5-methyl-2-pyrazoline, cyclopropyl ketone nitrogen/5-methyl-3, 5-dicyclohexyl pyrazoline mixture.
7. The method for separating pyrazoline isomer mixture by using the polar solvent resistant nanofiltration membrane according to claim 1, wherein the method comprises the following steps: the pyrazoline isomer mixture temperature in the step (2) is 25-50 ℃, the membrane operation pressure is 20-40bar, and the operation mode is cross-flow filtration.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1603313A (en) * | 2004-08-25 | 2005-04-06 | 长沙卷烟厂 | Method for separation purification of polyhydroxy-alkyl-pyrazine from suger amine reaction liquid |
| CN1952015A (en) * | 2005-10-19 | 2007-04-25 | 上海染料研究所有限公司 | Process for preparing lemon chrome |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1603313A (en) * | 2004-08-25 | 2005-04-06 | 长沙卷烟厂 | Method for separation purification of polyhydroxy-alkyl-pyrazine from suger amine reaction liquid |
| CN1952015A (en) * | 2005-10-19 | 2007-04-25 | 上海染料研究所有限公司 | Process for preparing lemon chrome |
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| 吡唑啉类化合物的典型合成及新应用;常金宇等;《辽宁化工》;第50卷(第11期);第1704-1707页 * |
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