A polyalkylene imine and a method for its preparation

Abstract

The application provides a polyalkylene imine and a preparation method thereof, and belongs to the field of high polymer materials. The method uses azepane as raw material and performs polymerization under the action of chloro ferric acid ionic liquid initiator. By controlling the acidity of the chloro ferric acid ionic liquid, the dosage, the concentration of azepane, the solvent, the polymerization temperature and the time, the control of the polymerization degree of the material can be effectively realized, and the corresponding polyalkylene imine material is formed. The method has the following advantages: (1) the reaction condition is mild, and high temperature and high pressure conditions are not needed; (2) the raw material conversion rate is as high as 99% or more, and the polymerization material is basically odorless; (3) the product has wide application range, and can be used in the polymerization reaction of azepine, azetidine, alkyl-substituted azepine, alkyl-substituted azetidine and other materials; (4) the obtained material has wide application in the fields of flocculants, corrosion inhibitors, liquid crystal polymers, coating layers, gel-type water shutoff agents, drug carriers and gene transfection.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, and more specifically, to a polyalkylene imide and its preparation method. Background Technology

[0002] Polyalkylimides are a class of cationic polymers with a general structure, whose backbone consists of secondary or tertiary amine units separated by alkylene spacer groups. Polyalkylimides can be used as adhesives, adhesion promoters, and pigment dispersants. Furthermore, they are excellent primers (e.g., for acrylate-based adhesives) and are used as amine components in epoxy and polyurethane resins. In papermaking, polyalkylimides can be used as retention and filtration aids to improve paper recovery and promote closed-loop water recycling. They can also be used as chelating agents for heavy metal ions (such as copper, rhodium, mercury, and zinc), enriching these elements from aqueous solutions. Polyalkylimides can be used in pretreatment and post-treatment of dyeing processes to improve dye fixation and fastness. Additionally, they can improve the antistatic properties of hydrophobic fibers and enhance shrinkage resistance. Polyalkylimides show broad application prospects in drug delivery and gene delivery.

[0003] Polyalkylimide materials are generally produced by reacting an initiator such as hydrochloric acid in an aqueous solution. However, this method is characterized by violent reactions, numerous byproducts, low product conversion rate, poor controllability, wide molecular weight distribution, and difficulty in obtaining high molecular weight materials.

[0004] Therefore, there is an urgent need to provide a method for preparing polyalkylimides that is mild, has a high product conversion rate, and does not produce side reactions such as hydrolysis caused by traditional aqueous phases. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide a polyalkylene imide and its preparation method. The method has mild reaction conditions and does not require high temperature and high pressure conditions; the raw material conversion rate is as high as 99% or more, and the polymer material is basically odorless; in addition, the product has a wide range of applications.

[0006] To solve the above problems, the present invention adopts the following technical solution.

[0007] A method for preparing polyalkylene imine is as follows: azacycloalkanes are dissolved in an aprotic solvent, followed by the addition of ferric chloride ionic liquid initiator and co-initiator. After polymerization at elevated temperature, the ferric chloride ionic liquid initiator is separated, the solvent is recovered by distillation, diluted, and extracted by distillation to obtain polyalkylene imine.

[0008] Further, the azacyclic alkane is one or more selected from azacyclic propane, N-methylazacyclic propane, N-butylazacyclic propane, N-phenylazacyclic propane, azacyclic butane, N-methylazacyclic butane, N-ethylazacyclic butane, N-propylazacyclic butane, N-butylazacyclic butane, and N-phenylazacyclic butane. The azacyclic alkane is preferably azacyclic propane, N-butylazacyclic propane, N-phenylazacyclic propane, azacyclic butane, or N-phenylazacyclic butane.

[0009] Furthermore, the mass ratio of the azacycloalkane to the ferric chloride ionic liquid initiator is 100:2-20; preferably 100:8-18.

[0010] Furthermore, the ferric chloride ionic liquid initiator is prepared by the following method: after the amine undergoes a quaternization reaction with a primary chloroalkane with a carbon chain of 3-6, excess amine is removed by vacuum distillation, and anhydrous ferric chloride with a molar ratio of 0.5-2:1 to the quaternary ammonium salt is added and mixed. Subsequently, the target ferric chloride ionic liquid initiator is obtained by vacuum rotary evaporation.

[0011] Furthermore, the amine is triethylamine or tripropylamine, and the molar ratio of the amine to the primary chloroalkyl group is 1:1.2-3.

[0012] Furthermore, the quaternization reaction is carried out at a temperature of 60-85℃ for 8-24 h; the vacuum rotary evaporation reaction is carried out at a temperature of 65-90℃ for 4-12 h.

[0013] Furthermore, the aprotic solvent is acetonitrile, tetrahydrofuran, ethylene glycol diethyl ether, diethylene glycol diethyl ether, chlorobenzene, or o-dichlorobenzene. The aprotic solvent is preferably acetonitrile, tetrahydrofuran, or ethylene glycol diethyl ether; the mass ratio of the azacycloalkane to the aprotic solvent is 100:50-1000, preferably 100:80-300.

[0014] Further, the co-initiator is 1,2-dichloroethane, 1,4-dichlorobutane, 1,3-dichloropropane, 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,2-diiodoethane, 1,3-diiodopropane, or 1,4-diiodobutane. The co-initiator is preferably 1,2-dichloroethane, 1,2-dibromoethane, or 1,3-dichloropropane. The mass ratio of the co-initiator to the azacycloalkanes is 1-15:100, preferably 3-10:100.

[0015] Furthermore, the reaction temperature is 45-110℃; the reaction time is 4-72h; and the specific operation of distillation extraction is: steam distillation extraction at 95-110℃ for 8-24h under nitrogen protection.

[0016] Furthermore, the preparation method is as follows: 100 parts by weight of azacycloalkanes are dissolved in 50-1000 parts by weight of acetonitrile, tetrahydrofuran, ethylene glycol diethyl ether, diethylene glycol diethyl ether, chlorobenzene, or o-dichlorobenzene, an aprotic solvent. Then, 2-20 parts by weight of ferric chloride ionic liquid initiator and 1-15 parts by weight of 1,2-dichloroethane, 1,4-dichlorobutane, 1,3-dichloropropane, 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,2-diiodoethane, 1,3-diiodopropane, or 1,4-diiodobutane co-initiator are added. The mixture is heated to 45-110℃ and polymerized for 4-72 hours. After separating the ferric chloride ionic liquid by magnetic adsorption, the solvent is recovered by distillation. After dilution with water, the mixture is extracted by steam distillation at 95-110℃ for 8-24 hours under nitrogen protection. The water is removed by vacuum distillation to obtain polyalkylene imide.

[0017] Furthermore, the azacyclic alkane includes one or more of azacyclic propane, N-methylazacyclic propane, N-butylazacyclic propane, N-phenylazacyclic propane, azacyclic butane, N-methylazacyclic butane, N-ethylazacyclic butane, N-propylazacyclic butane, N-butylazacyclic butane, and N-phenylazacyclic butane.

[0018] Furthermore, the ferric chloride ionic liquid initiator contains ferric chloride anions with different ferric chloride atomic ratios. First, triethylamine or tripropylamine is reacted with a primary chloroalkane with a carbon chain of 3-6 at 60-85°C for 8-24 h to form the corresponding quaternary ammonium salt. Then, anhydrous ferric chloride with a molar ratio of 0.5-2 to the quaternary ammonium salt is added and mixed. The mixture is then subjected to vacuum rotary evaporation at 65-90°C for 4-12 h to obtain the corresponding ferric chloride ionic liquid initiator.

[0019] The present invention also provides a polyalkylene imide prepared by the above-described method, the general chemical formula of which is shown below: ; R1, R2, R3 are independently selected from one or more combinations of hydrogen, methyl, ethyl, propyl, butyl, and phenyl, where X is 2-10000 and Y is 2-1000.

[0020] The present invention also provides the application of the above-mentioned polyalkylene imide.

[0021] The present invention also provides an application of polyalkylene imide, which is used as a drug carrier and gene transfection agent, corrosion inhibitor, liquid crystal polymer, coating, gel-type water-blocking agent or flocculant.

[0022] Compared with the prior art, the advantages of this invention are: I. This method has mild reaction conditions, does not require high temperature and high pressure conditions, and the product yield is as high as 95% or more. The polymer material is basically odorless.

[0023] II. The polyalkylene imine provided in this solution has a wide range of applications and can be used for the polymerization reaction of materials such as aziridine, aziridine, alkyl-substituted aziridine, and alkyl-substituted aziridine.

[0024] Third, this scheme uses ferric chloride ionic liquid initiator. By adjusting the alkyl chain and ferric chloride ratio of the initiator, the initiation efficiency can be effectively controlled, thereby achieving effective control of the molecular structure of the polymer material. The ferric chloride initiator is separated by magnetic adsorption, which greatly reduces the post-processing. The use of non-protic solvent avoids side reactions such as hydrolysis caused by traditional aqueous phases, making it the most suitable method at present. Detailed Implementation

[0025] This invention uses ferric chloride ionic liquid as an initiator in aprotic solvents such as acetonitrile, tetrahydrofuran, ethylene glycol diethyl ether, diethylene glycol diethyl ether, chlorobenzene, and dichlorobenzene, and co-initiators such as dichloroethane, dichlorobutane, dichloropropane, dibromoethane, dibromopropane, and dibromobutane. The corresponding polyalkylene imide materials are prepared through polymerization, magnetic separation of ferric chloride ionic liquid, distillation recovery of solvent, and steam distillation extraction.

[0026] The preferred embodiments of the present invention will be described in detail below in order to better understand the purpose, features and advantages of the present invention.

[0027] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1:

[0029] Preparation of ferric chloride ionic liquid initiator: First, triethylamine and n-butyl chloride were heated and stirred at 65°C for 12 h at a molar ratio of 1:1.2 to form the corresponding quaternary ammonium salt. Excess n-butyl chloride was removed by vacuum distillation. Then, anhydrous ferric chloride was added and mixed with the quaternary ammonium salt at a molar ratio of 1.0:1. The mixture was then subjected to vacuum rotary evaporation at 85°C for 10 h to obtain the corresponding ferric chloride ionic liquid initiator. Preparation of polyalkyleneimide material: 100 parts by mass of aziridine were dissolved in 100 parts by mass of acetonitrile, then 15 parts by mass of ferric chloride ionic liquid initiator and 4 parts by mass of 1,2-dichloroethane co-initiator were added. The mixture was heated to 65°C and polymerized for 12 hours. After separating the ferric chloride ionic liquid by magnetic adsorption, the solvent was recovered by distillation. After dilution with 100 parts by mass of water, the mixture was extracted by steam distillation at 95-110°C for 12 hours under nitrogen protection. The corresponding polyethyleneimine material was obtained by vacuum distillation to remove water, with a yield of 98% and a molecular weight of 1765. The viscosity of a 30wt% aqueous solution was 35 mPa·s / 25°C. After standing for one month, the viscosity of the aqueous solution was 34 mPa·s / 25°C.

[0030] Examples 2-7: Examples 2-7 differ from Example 1 in that different nitrogen-containing heterocyclic alkanes were selected, while other conditions remained the same as in Example 1. The yields, molecular weights, and viscosities of the polyalkylene imides generated under these conditions are shown in Table 1.

[0031] ; As can be seen from Examples 1-7, the preparation method provided by the present invention has a wide range of applications and can be applied to a variety of nitrogen-containing heterocyclic alkane monomers (including three-membered rings and four-membered rings), and the reaction conditions are mild. In addition, the viscosity of the polyalkylene imide prepared in this application does not change by more than 2 mPa·s after being placed at 25°C for one month, indicating that the polyalkylene imide prepared by this method has good long-term stability and can be stored for a long time.

[0032] Examples 8-13: Examples 8-13 differ from Example 1 in that they use ferric chloride ionic liquids prepared from different amounts of anhydrous ferric chloride, while other reaction conditions remain the same as in Example 1. The yield, molecular weight, and viscosity of the polyethyleneimine prepared under these conditions are shown in Table 2.

[0033] ; As shown in Examples 1 and 8-13, with the increase of ferric chloride dosage, the activity of the initiator is enhanced, enabling more efficient initiation of polymerization and the formation of materials with higher molecular weights. This also demonstrates that by adjusting the composition of the initiator, the molecular weight of the product can be effectively controlled.

[0034] Examples 14-19: Examples 14-19 differ from Example 1 in that the amount of ferric chloride ionic liquid initiator was changed, while other reaction conditions remained the same as in Example 1. The yield, molecular weight, and viscosity of the polyethyleneimine prepared under these conditions are shown in Table 3.

[0035] ; As shown in Examples 1 and 14-19, the molecular weight of the product decreases with increasing initiator dosage, but increases with decreasing initiator dosage. Therefore, the molecular weight of the product can be effectively controlled by adjusting the amount of initiator used.

[0036] Examples 20-23: Examples 20-23 differ from Example 1 in that ferric chloride ionic liquids prepared based on different primary chloroalkyl groups were used as initiators, while other reaction conditions remained the same as in Example 1. The yield, molecular weight, and viscosity data of the polyethyleneimine prepared under these conditions are detailed in Table 4.

[0037] ; As shown in Examples 1 and 20-23, the initiation activity changes and the molecular weight of the product decreases as the initiator chain length increases. Therefore, the molecular weight of the product can be effectively controlled by adjusting the initiator chain length.

[0038] Comparative Example 1 without using an ionic liquid initiator: According to Example 1, without using an ionic liquid initiator, 100 parts by weight of aziridine were dissolved in 100 parts by weight of acetonitrile, and then 4 parts by weight of dichloroethane co-initiator were added. The mixture was heated to 65°C and polymerized for 12 hours. The solvent was recovered by distillation, and after dilution with 100 parts by weight of water, it was extracted by steam distillation at 95-110°C for 12 hours under nitrogen protection. The water was removed by vacuum distillation to obtain the corresponding polyalkylene imide material with a yield of 40% and a molecular weight of 254. The viscosity of the 30% aqueous solution was 12 mPa·s / 25°C, and after one month, it was 33 mPa·s / 25°C.

[0039] Comparative Example 2 without using a co-initiator: According to Example 1, without using a co-initiator, 100 parts by weight of aziridine were dissolved in 100 parts by weight of acetonitrile, and then 15 parts by weight of ferric chloride ionic liquid initiator were added. The mixture was heated to 65°C and subjected to polymerization for 12 hours. After separating the ferric chloride ionic liquid by magnetic adsorption, the solvent was recovered by distillation. After diluting with 100 parts by weight of water, the mixture was extracted by steam distillation at 95-110°C for 12 hours under nitrogen protection. The water was removed by vacuum distillation to obtain the corresponding polyalkylene imide material with a yield of 88% and a molecular weight of 865. The viscosity of the 30% aqueous solution was 17 mPa·s / 25°C, and after one month, it was 29 mPa·s / 25°C.

[0040] As can be seen from Examples 1-8 and Comparative Examples 1-2, the preparation method of the present invention has mild reaction conditions and does not require high temperature and high pressure conditions; the raw material conversion rate is as high as 95% or more, and the polymerized material is basically odorless; the product has a wide range of applications and can be used for the polymerization reaction of materials such as aziridine propane, aziridine butane, alkyl-substituted aziridine propane, and alkyl-substituted aziridine butane; the obtained material has wide applications in the fields of flocculants (clarifying agents), corrosion inhibitors, liquid crystal polymers, coatings, gel-type water-blocking agents, drug carriers, and gene transfection.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing polyalkylene imine, characterized in that: The preparation method is as follows: Azacycloalkanes are dissolved in an aprotic solvent, followed by the addition of ferric chloride ionic liquid initiator and co-initiator. After heating and polymerization, the ferric chloride ionic liquid initiator is separated, the solvent is recovered by distillation, diluted, and extracted by distillation to obtain polyalkylene imide.

2. The method for preparing a polyalkylene imide according to claim 1, characterized in that: The azacyclic alkane is one or more of the following: azacyclic propane, N-methylazacyclic propane, N-butylazacyclic propane, N-phenylazacyclic propane, azacyclic butane, N-methylazacyclic butane, N-ethylazacyclic butane, N-propylazacyclic butane, N-butylazacyclic butane, and N-phenylazacyclic butane.

3. The method for preparing a polyalkylene imide according to claim 1, characterized in that: The mass ratio of the azacycloalkane to the ferric chloride ionic liquid initiator is 100:2-20.

4. The method for preparing a polyalkylene imide according to claim 1, characterized in that: The ferric chloride ionic liquid initiator is prepared by the following method: after the amine undergoes a quaternization reaction with a primary chloroalkane with a carbon chain of 3-6, excess amine is removed by vacuum distillation, and anhydrous ferric chloride with a molar ratio of 0.5-2:1 to the quaternary ammonium salt is added and mixed. Subsequently, the target ferric chloride ionic liquid initiator is obtained by vacuum rotary evaporation.

5. The method for preparing a polyalkylene imide according to claim 4, characterized in that: The amine is triethylamine or tripropylamine, and the molar ratio of the amine to the primary chloroalkyl group is 1:1.2-3.

6. The method for preparing a polyalkylene imide according to claim 4, characterized in that: The quaternization reaction is carried out at a temperature of 60-85℃ for 8-24 h; the vacuum rotary evaporation reaction is carried out at a temperature of 65-90℃ for 4-12 h.

7. The method for preparing a polyalkylene imide according to claim 1, characterized in that: The aprotic solvent is acetonitrile, tetrahydrofuran, ethylene glycol diethyl ether, diethylene glycol diethyl ether, chlorobenzene, or o-dichlorobenzene; the mass ratio of the azacycloalkane to the aprotic solvent is 100:50-1000.

8. The method for preparing a polyalkylene imide according to claim 1, characterized in that: The co-initiator is 1,2-dichloroethane, 1,4-dichlorobutane, 1,3-dichloropropane, 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,2-diiodoethane, 1,3-diiodopropane, or 1,4-diiodobutane; the mass ratio of the co-initiator to the azacyclic alkanes is 1-15:

100.

9. The method for preparing a polyalkylene imide according to claim 1, characterized in that: The reaction temperature is 45-110℃; the reaction time is 4-72h; the specific operation of distillation extraction is: steam distillation extraction at 95-110℃ for 8-24h under nitrogen protection.

10. A polyalkylene imide prepared by the method for preparing a polyalkylene imide according to any one of claims 1-9, characterized in that: The general chemical structural formula is shown below: ； R1, R2, R3 are independently selected from one or more combinations of hydrogen, methyl, ethyl, propyl, butyl, and phenyl, where X is 2-10000 and Y is 2-10000.

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