Preparation method of heterogeneous nickel supported catalyst composite membrane and styrene permeation polymerization method based on composite membrane
By bonding the tetraaminophenylporphyrin nickel catalyst with the polyimide material, a heterogeneous catalyst composite film was prepared, which solved the problem of low catalyst recovery and reuse efficiency in traditional polystyrene preparation methods, and achieved efficient catalyst recovery and precise control of the molecular weight of polystyrene.
Patent Information
- Application Number
- CN202510158232.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-12
- Publication Date
- 2025-05-06
AI Technical Summary
The traditional polystyrene preparation method has problems such as high temperature and high pressure conditions, the use of a large number of emulsifiers and surfactants, and the low efficiency of catalyst recovery and reuse. In particular, the catalyst is difficult to accurately control during the polymerization process, and the nanoparticle catalyst is prone to agglomeration and difficult to recover.
By bonding the tetraaminophenylporphyrin nickel catalyst with the polyimide material, a tetraaminophenylporphyrin nickel/polyimide heterogeneous catalyst composite film was prepared, and the composite film was used to permeate the styrene to achieve efficient recovery and recycling of the catalyst.
This method achieves precise control of the molecular weight of the permeable polymerization product, ensures efficient recovery and multiple utilization of the catalyst, reduces costs, and avoids the aggregation problem of nanoparticle catalysts.
Smart Images
Figure CN119931109A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a method for preparing a heterogeneous nickel-loaded catalyst composite membrane and a styrene permeation polymerization method based on the composite membrane. Background Art
[0002] Olefin monomer polymers are widely used in many fields such as plastics, synthetic rubber, fibers, coatings, medical devices, and electronic products. Due to their excellent performance, they meet the needs of various industries. Take polystyrene as an example. As a common thermoplastic, it has excellent formability, transparency, weather resistance and cost-effectiveness. It is widely used in packaging materials, building insulation, medical equipment and other fields. In industry, common preparation methods of polystyrene include suspension polymerization, emulsion polymerization, gas phase polymerization and solution polymerization. However, these traditional methods have certain problems in practical applications: suspension polymerization and gas phase polymerization require high temperature and high pressure conditions, and have high requirements for equipment and operation; emulsion polymerization requires the use of a large amount of emulsifiers and surfactants, which may affect the purity of the product and cause pollution to the environment; and in the solution polymerization process, the co-catalyst and catalyst will be dispersed in the solution, which makes the reaction difficult to accurately control, and the recovery and reuse efficiency of the catalyst is low.
[0003] In the process of olefin monomer solution polymerization, the role of catalysts is crucial. At present, catalysts suitable for olefin monomer solution polymerization are mainly divided into two categories: homogeneous catalysts and heterogeneous catalysts. Although homogeneous catalysts can be evenly dispersed in the solvent, thereby improving the efficiency of the reaction, their recovery and reuse are very difficult, especially for expensive catalysts, the loss will significantly increase the cost. In contrast, heterogeneous catalysts, especially by loading the catalyst on carbon nanotubes, SiO 2 New catalysts formed on nanoparticles such as nanoparticles have become a hot topic in recent years. However, the loaded catalysts are still dispersed in the mixed solution during the polymerization process, making it difficult to accurately control the reaction process. In addition, nanoparticles are prone to agglomeration as heterogeneous catalysts, and the efficient recovery of catalysts is still challenging. In addition, the risk of catalyst ligand shedding cannot be ignored. Summary of the invention
[0004] In view of this, in order to solve the problems raised in the above-mentioned background technology, the object of the present invention is to provide a kind of preparation method of heterogeneous nickel supported catalyst composite membrane and styrene permeation polymerization method based on the composite membrane.The method successfully prepares tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane by bonding the amino group in tetraaminophenylporphyrin nickel catalyst with high temperature resistant polyimide material.Utilize the composite membrane, can effectively separate the cocatalyst and styrene monomer solution, the cocatalyst promotes styrene monomer to occur polymerization reaction on the side surface of heterogeneous catalytic membrane by permeating to the other side of the membrane.Because the catalyst is loaded in the macrostructure of polyimide-based membrane, not only can realize the accurate control of the molecular weight of the permeation polymerization reaction product, can also by removing the heterogeneous catalyst composite membrane, ensure the efficient recovery and recycling of catalyst, thereby improve the use efficiency of catalyst and reduce cost.
[0005] To achieve the above object, the present invention provides the following technical solutions:
[0006] A method for preparing a heterogeneous nickel-supported catalyst composite membrane comprises:
[0007] First, tetraaminophenylporphyrin nickel and 4,4-diaminodiphenyl ether are mixed and dissolved in N,N-dimethylformamide, and then hexafluorodianhydride is slowly mixed in, and after sufficient stirring and reaction, a tetraaminophenylporphyrin nickel / polyimide mixed solution is obtained;
[0008] The tetraaminophenylporphyrin nickel / polyimide mixed solution is evenly poured onto a clean glass plate, allowed to stand for natural crosslinking, and then dried to obtain a tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane.
[0009] Preferably, the preparation steps of the tetraaminophenylporphyrin nickel include:
[0010] Dissolve tetraaminophenylporphyrin and anhydrous nickel chloride in N,N-dimethylformamide at 80°C, heat to 130°C under nitrogen protection, and stir to react for 12 hours;
[0011] The reactants are transferred into deionized water, separated by suction filtration, washed and dried to obtain nickel tetraaminophenylporphyrin.
[0012] Preferably, the mixing molar ratio of the tetraaminophenylporphyrin nickel, 4,4-diaminodiphenyl ether and hexafluorodianhydride is 1-1.2:9-10:10.5-11.
[0013] Preferably, the hexafluorodianhydride is uniformly mixed into N,N-dimethylformamide in batches, and stirred for 10 to 30 minutes after each addition.
[0014] Preferably, the hexafluorodianhydride is added at least four times.
[0015] Preferably, the glass plate is soaked and cleaned with a methanol solution, then thoroughly rinsed with deionized water and dried.
[0016] Preferably, the step of drying the tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane comprises:
[0017] The glass plate coated with the tetraaminophenylporphyrin nickel / polyimide mixed solution was placed in an oven at 60-90°C and heated for 1 hour;
[0018] Raise the oven temperature to 280°C and continue drying for 1 to 2 hours;
[0019] The glass plate is kept in the oven and the temperature is gradually lowered to room temperature to obtain a tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane.
[0020] Preferably, the oven gradually increases the temperature to 280° C. at a heating rate of 40° C. / 1.5 h.
[0021] A styrene permeation polymerization method based on a heterogeneous nickel-supported catalyst composite membrane comprises:
[0022] Provided is a reaction device comprising a left reaction chamber, a right reaction chamber and a channel, wherein the left reaction chamber is connected to the right reaction chamber through the channel, and the heterogeneous nickel-supported catalyst composite membrane according to any one of claims 1 to 8 is installed in the channel;
[0023] Under nitrogen protection, styrene solution is injected into the left reaction chamber, and trimethylaluminum and toluene are injected into the right reaction chamber in sequence, maintaining the liquid levels on both sides at the same height, and polymerizing to form polystyrene.
[0024] Preferably, the volume ratio of trimethylaluminum to toluene is 1:1.
[0025] Compared with the prior art, the present invention has the following beneficial effects:
[0026] (1) The present invention provides an innovative experimental method for permeation polymerization, prepares a tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane, and allows the catalyst to be loaded and bonded into the polyimide membrane. When the co-catalyst passes through the membrane, the catalyst is prompted to play a role, thereby achieving the effect of permeation polymerization. In the later stage, the heterogeneous catalyst composite membrane can be recovered to achieve effective multiple utilization of the catalyst. This method solves the problems of metal nanoparticles that are common in traditional catalysts, such as easy agglomeration and difficulty in recovery, and is of great significance for reducing the input of nickel and thus reducing costs.
[0027] (2) The materials that make up the heterogeneous catalyst composite membrane have excellent properties. Among them, tetraaminophenylporphyrin is a macromolecular heterocyclic compound formed by connecting the α-carbon atoms of four pyrrole subunits through a mesityle bridge (=CH-). Its porphyrin ring structure can firmly fix metal ions and maintain good structural stability at high temperatures. Polyimide is a high-performance polymer material with excellent mechanical properties. At the same time, polyimide exhibits good chemical stability to most acids, bases, oxidants and organic solvents. By combining the tetraaminophenylporphyrin metal ion catalyst with polyimide, the rich amino groups of the catalyst can make it evenly distributed in the membrane, significantly improving the stability of the catalyst.
[0028] (3) Based on the permeation polymerization provided by the present invention, at different reaction times, as the reaction time increases, the yield of polystyrene gradually increases, and precise control of the molecular weight is effectively achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 The schematic diagram of the permeation polymerization reaction based on the tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane and the reaction device of the present invention are shown;
[0030] Figure 2 This is the infrared spectrum of the tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite film;
[0031] Figure 3 is the X-ray photoelectron spectroscopy (XPS) diagram of the tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite film;
[0032] Figure 4 This is a cross-sectional scanning electron microscope image of the tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane after permeation polymerization. DETAILED DESCRIPTION
[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0034] (I) Preparation of nickel tetraaminophenylporphyrin
[0035] S11. Tetraaminophenylporphyrin (2.0 mmol, 1349.58 mg) and anhydrous nickel chloride (3.0 mmol, 388.77 mg) were dissolved in N,N-dimethylformamide (20 mL) at 80°C.
[0036] S12. Nitrogen was introduced, heated to 130°C under nitrogen protection, and stirred for 12h;
[0037] S13. The reactants were transferred into deionized water and separated by suction filtration to obtain a precipitated solid product;
[0038] S14. Rinse the solid product several times with deionized water until the filtrate is clear;
[0039] S15. The obtained purple-red filter cake is transferred to a vacuum drying oven for drying to obtain tetraaminophenylporphyrin nickel.
[0040] (II) Preparation of tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane
[0041] The reaction formula is as follows:
[0042]
[0043] The specific preparation steps are as follows:
[0044] S21. First, tetraaminophenylporphyrin nickel (0.2 mmol, 146.3 mg) and 4,4-diaminodiphenyl ether (1.8 mmol, 360.4 mg) were added to a three-necked flask, and then N,N-dimethylformamide (12 mL) was added and stirred to dissolve;
[0045] S22. Hexafluorodianhydride (2.0 mmol, 888.48 mg) was evenly divided into four equal parts, and added to a three-necked flask in batches. After each addition, it was stirred for 20 min until it was completely dissolved to obtain a tetraaminophenylporphyrin nickel / polyimide mixed solution (wherein, when the hexafluorodianhydride was added for the last time, the stirring time should be controlled between 5 and 10 min, and the state of the mixed solution should be closely observed to avoid gelation, because gelation will affect the subsequent film-forming process. To further optimize the stirring time, it can be set to 8 min to ensure uniform mixing and not cause solution gelation. In addition, this process is an exothermic reaction, so an ice bath can be used to promote the reaction);
[0046] S23. A smooth glass plate was soaked and cleaned with methanol solution, then rinsed thoroughly with deionized water, and dried for later use;
[0047] S24. Pour the tetraaminophenylporphyrin nickel / polyimide mixed solution evenly onto a clean glass plate and allow it to stand for natural crosslinking;
[0048] S25. The glass plate coated with the tetraaminophenylporphyrin nickel / polyimide mixed solution was placed in an oven at 80°C and heated for 1 h; the temperature in the oven was raised to 280°C at a heating rate of 40°C / 1.5h and then continued to dry for 1 to 2h;
[0049] S26. Keep the glass plate in the oven and gradually lower the temperature to room temperature to obtain a tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane.
[0050] For the tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane prepared above:
[0051] like Figure 2 As shown in the infrared spectrum, 1777cm -1 The characteristic absorption peak of C=O in the imide ring is 1618 cm -1 and 1484cm -1 The peaks at 1241 cm-1 correspond to the stretching vibration peaks of the benzene ring skeleton, while the peaks at 1241 cm-1 correspond to the stretching vibration peaks of the benzene ring skeleton. -1 It corresponds to the stretching vibration peak of Ph-O-Ph.
[0052] like Figure 3 As shown in the figure, compared with the traditional polyimide membrane without the addition of tetraaminophenylporphyrin nickel catalyst, the prepared tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane shows the characteristic peak of Ni element in the whole spectrum. In the fine spectrum of N1s, the characteristic peak of nitrogen (N-Ni) combined with Ni appears at 400eV; in the fine spectrum of Ni2p, the characteristic peaks of Ni2p are also observed at 850eV and 870eV.
[0053] In summary, these results indicate that nickel tetraaminophenylporphyrin was successfully composited with polyimide to form a film.
[0054] (III) Osmotic polymerization
[0055] like Figure 1 As shown in the right figure, a reaction device is provided, which includes a left reaction chamber, a right reaction chamber and a channel, wherein the left reaction chamber is connected with the right reaction chamber through the channel, and the heterogeneous nickel-supported catalyst composite membrane is installed in the channel;
[0056] Under nitrogen protection (vacuum for 10 min, then introduce nitrogen for 15 min), inject styrene solution (30 mL) into the left reaction chamber, and inject trimethylaluminum (15 mL) and toluene (15 mL) into the right reaction chamber in sequence, maintaining the liquid levels on both sides at the same height, and polymerize to form polystyrene.
[0057] Regarding the permeation polymerization reaction, the entire reaction apparatus was always kept in a nitrogen atmosphere, and the synthesis progress of polystyrene was monitored in real time by observing the color change and viscosity of the styrene end solution.
[0058] After the permeation polymerization reaction was completed, the tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane was scanned by electron microscope. The results are as follows Figure 4As shown: After the osmotic polymerization reaction, the surface of the composite membrane in contact with the styrene solution protruded, and a polystyrene layer was generated. Elemental analysis of the tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane showed that no nickel element was detected in the polystyrene generated on the surface. The nickel element only existed inside the composite membrane and was not lost during the osmotic polymerization process. This phenomenon shows that the composite membrane can maintain the stability of the nickel catalyst during the osmotic polymerization process, and the generated polystyrene layer proves the success of the osmotic polymerization process.
[0059] In addition, the yield, weight average molecular weight and molecular weight distribution of polystyrene under different reaction times are shown in Table 1 below. Under different reaction time conditions, as the reaction time increases, the yield of polystyrene gradually increases, indicating that the reaction continues without interruption. The weight average molecular weight (M) of polystyrene obtained in the five experiments w ) are stable at about 4.1×10 4 , and its molecular weight distribution is very narrow, indicating that the permeation polymerization method based on tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane can successfully prepare polystyrene with a specific molecular weight and achieve precise control of the molecular weight.
[0060]
[0061] In summary, the present invention innovatively connects the tetraaminophenylporphyrin nickel catalyst with polyimide through chemical bonding to prepare a tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane. The composite membrane is laid in a specific device as an intermediate spacer. Under nitrogen protection conditions, styrene monomer and the required co-catalyst are respectively injected into the left and right sides of the device, and the co-catalyst realizes the permeation polymerization of styrene monomer through the membrane.
[0062] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a heterogeneous nickel-supported catalyst composite membrane, characterized in that: include: First, tetraaminophenylporphyrin nickel and 4,4-diaminodiphenyl ether are mixed and dissolved in N,N-dimethylformamide, and then hexafluorodianhydride is slowly mixed in, and after sufficient stirring and reaction, a tetraaminophenylporphyrin nickel / polyimide mixed solution is obtained; The tetraaminophenylporphyrin nickel / polyimide mixed solution is evenly poured onto a clean glass plate, allowed to stand for natural crosslinking, and then dried to obtain a tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane.
2. The method for preparing a heterogeneous nickel-supported catalyst composite membrane according to claim 1, characterized in that: The preparation steps of the tetraaminophenylporphyrin nickel include: Dissolve tetraaminophenylporphyrin and anhydrous nickel chloride in N,N-dimethylformamide at 80°C, heat to 130°C under nitrogen protection, and stir to react for 12 hours; The reactants are transferred into deionized water, separated by suction filtration, washed and dried to obtain nickel tetraaminophenylporphyrin.
3. The method for preparing a heterogeneous nickel-supported catalyst composite membrane according to claim 1, characterized in that: The mixing molar ratio of the tetraaminophenylporphyrin nickel, 4,4-diaminodiphenyl ether and hexafluorodianhydride is 1-1.2:9-10:10.5-11.
4. The method for preparing a heterogeneous nickel-supported catalyst composite membrane according to claim 3, characterized in that: The hexafluorodianhydride is uniformly mixed into N,N-dimethylformamide in batches, and stirred for 10 to 30 minutes after each addition.
5. The method for preparing a heterogeneous nickel-supported catalyst composite membrane according to claim 4, characterized in that: The hexafluorodianhydride is added in at least four portions.
6. The method for preparing a heterogeneous nickel-supported catalyst composite membrane according to claim 1, characterized in that: The glass plate is soaked and cleaned with a methanol solution, then thoroughly rinsed with deionized water and dried.
7. The method for preparing a heterogeneous nickel-supported catalyst composite membrane according to claim 1, characterized in that: The drying step of the tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane comprises: The glass plate coated with the tetraaminophenylporphyrin nickel / polyimide mixed solution was placed in an oven at 60-90°C and heated for 1 hour; Raise the oven temperature to 280°C and continue drying for 1 to 2 hours; The glass plate is kept in the oven and the temperature is gradually lowered to room temperature to obtain a tetraaminophenylporphyrin nickel / polyimide heterogeneous catalyst composite membrane.
8. The method for preparing a heterogeneous nickel-supported catalyst composite membrane according to claim 7, characterized in that: The temperature of the oven was gradually increased to 280° C. at a heating rate of 40° C. / 1.5 h.
9. A styrene permeation polymerization method based on a heterogeneous nickel-supported catalyst composite membrane, characterized in that: include: Provided is a reaction device comprising a left reaction chamber, a right reaction chamber and a channel, wherein the left reaction chamber is connected to the right reaction chamber through the channel, and the heterogeneous nickel-supported catalyst composite membrane according to any one of claims 1 to 8 is installed in the channel; Under nitrogen protection, styrene solution is injected into the left reaction chamber, and trimethylaluminum and toluene are injected into the right reaction chamber in sequence, maintaining the liquid levels on both sides at the same height, and polymerizing to form polystyrene.
10. The method for styrene percolation polymerization based on a heterogeneous nickel-supported catalyst composite membrane according to claim 9, characterized in that: The volume ratio of trimethylaluminum to toluene is 1:1.