阅读说明：本技术 一种聚苯并咪唑衍生物及其制备方法和金属离子循环吸附的应用 (Polybenzimidazole derivative, preparation method thereof and application of polybenzimidazole derivative in cyclic adsorption of metal ions ) 是由 汪朝阳 庞楚明 罗时荷 曹西颖 于 2020-12-09 设计创作，主要内容包括：本发明公开了一种聚苯并咪唑衍生物及其制备方法和金属离子循环吸附的应用。本发明的聚苯并咪唑衍生物的主链结构为：式中,R～1、R～2、R～3、R～4和R～5均独立地选自-H或n-C-5H-(11)-,x为0～8的自然数,y为0～8的自然数,且x和y不能同时为0。本发明的聚苯并咪唑衍生物的制备方法包括以下步骤：1)进行3,3’-二氨基联苯胺和戊二酸的共聚反应,得到聚苯并咪唑中间体；2)进行聚苯并咪唑中间体和1-溴戊烷的反应,得到聚苯并咪唑衍生物。本发明的聚苯并咪唑衍生物对铜离子具有高效吸附性能,并可以通过光学信号指示吸附进程,且在常见有机溶剂中的溶解性好,制备简单,成本低。(The invention discloses a polybenzimidazole derivative, a preparation method thereof and application of metal ion cyclic adsorption. The main chain structure of the polybenzimidazole derivative is as follows: in the formula, R 1 、R 2 、R 3 、R 4 And R 5 Are all independently selected from-H or n-C 5 H 11 X is a natural number of 0 to 8, y is a natural number of 0 to 8, and x and y cannot be 0 at the same time. The preparation method of the polybenzimidazole derivative comprises the following steps: 1) carrying out copolymerization reaction of 3,3' -diaminobenzidine and glutaric acid to obtain a polybenzimidazole intermediate; 2) carrying out polybenzimidazole intermediates and 1-And reacting bromopentane to obtain the polybenzimidazole derivative. The polybenzimidazole derivative has high-efficiency adsorption performance on copper ions, can indicate an adsorption process through an optical signal, and has good solubility in common organic solvents, simple preparation and low cost.)

1. A polybenzimidazole derivative is characterized in that the main chain structure is as follows:

in the formula, R¹、R²、R³、R⁴And R⁵Are all independently selected from-H or n-C₅H₁₁X is a natural number of 0 to 8, y is a natural number of 0 to 8, and x and y cannot be 0 at the same time.

2. The polybenzimidazole derivative according to claim 1, wherein: the number average molecular weight of the polybenzimidazole derivative is 1700g/mol to 5600 g/mol.

3. The method for producing a polybenzimidazole derivative according to claim 1 or 2, comprising the steps of:

1) carrying out copolymerization reaction of 3,3' -diaminobenzidine and glutaric acid to obtain a polybenzimidazole intermediate;

2) the polybenzimidazole intermediate and 1-bromopentane are reacted to obtain the polybenzimidazole derivative.

4. The method for producing a polybenzimidazole derivative according to claim 3, comprising the steps of:

1) mixing 3,3' -diaminobenzidine, glutaric acid and polyphosphoric acid, and carrying out copolymerization reaction to obtain a polybenzimidazole intermediate;

2) the polybenzimidazole intermediate, 1-bromopentane and alkali metal hydroxide are dispersed in a solvent for reaction to obtain the polybenzimidazole derivative.

5. The method for producing a polybenzimidazole derivative according to claim 3 or 4, characterized in that: the molar ratio of the 3,3' -diaminobenzidine to the glutaric acid in the step 1) is 1: 1.0-1: 1.5.

6. The method for producing a polybenzimidazole derivative according to claim 3 or 4, characterized in that: the copolymerization reaction in the step 1) is carried out at 160-180 ℃, and the reaction time is 48-72 h.

7. The method for producing a polybenzimidazole derivative according to claim 3 or 4, characterized in that: the molar ratio of the polybenzimidazole intermediate to the 1-bromopentane in the step 2) is 1: 0.1-1: 5.0.

8. The method for producing a polybenzimidazole derivative according to claim 3 or 4, characterized in that: the reaction in the step 2) is carried out at 85-95 ℃ for 8-12 h.

9. The method for producing a polybenzimidazole derivative according to claim 4, characterized in that: and 2) the alkali metal hydroxide is at least one of NaOH and KOH.

10. Use of a polybenzimidazole derivative according to claim 1 or 2 for the adsorption of metal ions.

Technical Field

The invention relates to the technical field of adsorption materials, in particular to a polybenzimidazole derivative, a preparation method thereof and application of metal ion cyclic adsorption.

Background

With the development of economy and the promotion of global industrialization process, environmental problems are increasingly prominent, and a large amount of wastewater rich in heavy metal ions is generated. Heavy metals are very difficult to biodegrade, but instead can be concentrated hundreds of times under the biological amplification of the food chain and finally enter the human body. Heavy metals can interact strongly with proteins and enzymes in human body to inactivate them, and can also accumulate in some organs of human body to cause chronic poisoning. Therefore, development of a metal ion adsorbing material is necessary.

The metal ion adsorbing materials reported in the literature mainly comprise the following materials:

1) polyethyleneimine-based adsorbent material: and crosslinking polyethyleneimine by using glutaraldehyde as a crosslinking agent, reducing C ═ N, and further reacting to generate the crosslinked dithiocarbamate polymer adsorption material based on polyethyleneimine. The material can be used for various heavy metal ions (such as Cd)²⁺、Cu²⁺、Pb²⁺) The adsorption of (2) but the adsorption effect of polyethyleneimine on metal ions is different due to different molecular weights, so that different polyethyleneimine with different molecular weights are required to be adopted for different industrial wastewater in practical application, and the polymerization reaction is often difficult to control, so that the difficulty in obtaining an adsorption material with ideal performance is high;

2) membrane adsorption material: grafting functional groups onto polyvinylidene fluoride chain segments through free radical polymerization to obtain amphiphilic copolymers with metal ion adsorption performance, preparing the copolymers into membrane preparation liquid by using a phase inversion method to carry out membrane formation to prepare the membrane preparation liquid capable of separating Cu²⁺The forward osmosis membrane of (1). The material has high-efficiency separation effect, but the preparation process is complex and the cost is high;

3) graphene oxide-based adsorption material: at normal temperatureThen Graphene Oxide (GO) and triethylene tetramine (TETA) are reacted to prepare GO-TETA, and the GO-TETA is reacted with potassium cyanate to prepare the material which can be used for Cu²⁺An adsorbed graphene oxide adsorbent material. The material can be recycled, but relevant reports actually do not describe the recycling measures or methods in detail;

4) polyacrylonitrile-based adsorbent material: polymerizing polyacrylonitrile and sulfur under high temperature to generate polyacrylonitrile-sulfur polymer, and fixing the polyacrylonitrile-sulfur polymer in a melamine sponge skeleton structure by a hot solvent bonding method to obtain the polyacrylonitrile-sulfur polymer capable of selectively adsorbing Cu²⁺The material of (1). The material can realize the recovery of copper by means of an electrolytic cell, and can be combined with a precipitation method, an adsorption method and an electrolysis method for realizing the green treatment of metal pollution;

5) lysine diketopiperazine-based adsorbent material: copolymerization of lysine diketopiperazine, ethylene diamine and N, N' -methylene bisacrylamide is realized through Michael addition reaction mediated reverse suspension polymerization, and Cu with controllable degradation is obtained²⁺Adsorbing the material. The material is to Cu²⁺Has good adsorption effect, and can resist hydrolysis and prevent Cu²⁺Is released;

6) microgel adsorbing material: under the action of glycidyl methacrylate, the carbon quantum dots are functionalized and stably fixed in the microgel network, and the bifunctional material for detecting and adsorbing metal ions is obtained. The material can realize the aim of Hg²⁺、 Fe³⁺、Cu²⁺Sensitive detection of three metal ions, for Cu²⁺Has strong adsorption capacity and can realize reutilization, but has good effect on Hg²⁺And Fe³⁺The adsorption effect of (2) is poor.

Recently, Wang group has synthesized a biocompatible multidentate hydrogel by transamidation of hydrolyzed polyacrylamide and branched polyethyleneimine. The maximum adsorption capacity of the porous hydrogel for mixed metal ions is 482.2mg/g, the porous hydrogel can be reused, the adsorption efficiency is still kept above 85% after 5 times, but the signal indication in the adsorption process is lacked, and additional instruments or equipment are needed to indicate the adsorption signal.

In summary, the existing metal ion adsorbing materials are various in types, and most of the existing metal ion adsorbing materials are polymer materials based on different functional units, most of the existing metal ion adsorbing materials have the problems of very complex preparation methods, high production cost and difficulty in realizing quantitative production, only part of the existing metal ion adsorbing materials can be used for cyclic adsorption of heavy metal ions, and in addition, no indication is provided for adsorption signals.

Disclosure of Invention

An object of the present invention is to provide a polybenzimidazole derivative.

The second object of the present invention is to provide a process for producing the polybenzimidazole derivative.

The invention also aims to provide the application of the polybenzimidazole derivative in metal ion cyclic adsorption.

The technical scheme adopted by the invention is as follows:

a polybenzimidazole derivative, the main chain structure of which is:

in the formula, R¹、R²、R³、 R⁴And R⁵Are all independently selected from-H or n-C₅H₁₁X is a natural number of 0 to 8, y is a natural number of 0 to 8, and x and y cannot be 0 at the same time (x is 0 means that the degree of alkylation of the polybenzimidazole derivative is relatively low, and y is 0 means that the degree of alkylation of the polybenzimidazole derivative is relatively high).

Preferably, the number average molecular weight of the polybenzimidazole derivative is 1700g/mol to 5600 g/mol.

The preparation method of the polybenzimidazole derivative comprises the following steps:

1) carrying out copolymerization reaction of 3,3' -diaminobenzidine and glutaric acid to obtain a polybenzimidazole intermediate;

2) the polybenzimidazole intermediate and 1-bromopentane are reacted to obtain the polybenzimidazole derivative.

Preferably, the preparation method of the polybenzimidazole derivative comprises the following steps:

1) mixing 3,3' -diaminobenzidine, glutaric acid and polyphosphoric acid, and carrying out copolymerization reaction to obtain a polybenzimidazole intermediate;

2) the polybenzimidazole intermediate, 1-bromopentane and alkali metal hydroxide are dispersed in a solvent for reaction to obtain the polybenzimidazole derivative.

Further preferably, the method for preparing the polybenzimidazole derivative comprises the following steps:

1) mixing 3,3' -diaminobenzidine, glutaric acid and polyphosphoric acid, carrying out copolymerization reaction, cooling a reaction system to room temperature, adjusting the pH to 9-10 with NaOH aqueous solution, carrying out vacuum filtration, and leaching the filtered solid with an organic solvent to obtain a polybenzimidazole intermediate;

2) dispersing the polybenzimidazole intermediate, 1-bromopentane and alkali metal hydroxide in a solvent for reaction, cooling a reaction system to room temperature, performing rotary evaporation to remove the solvent, performing multiple times of water washing on the obtained solid, performing alternate leaching by using dichloromethane and ethanol, collecting an organic phase, and removing the solvent to obtain the polybenzimidazole derivative.

Preferably, the molar ratio of the 3,3' -diaminobenzidine to the glutaric acid in the step 1) is 1: 1.0-1: 1.5.

Preferably, the copolymerization reaction in the step 1) is carried out at 160-180 ℃, and the reaction time is 48-72 h.

Preferably, the molar ratio of the polybenzimidazole intermediate in the step 2) to 1-bromopentane is 1: 0.1-1: 5.0.

Preferably, the alkali metal hydroxide in step 2) is at least one of NaOH and KOH.

Preferably, the reaction in the step 2) is carried out at 85-95 ℃, and the reaction time is 8-12 h.

The invention has the beneficial effects that: the polybenzimidazole derivative has high-efficiency adsorption performance on copper ions, can indicate an adsorption process through an optical signal, and has good solubility in common organic solvents, simple preparation and low cost.

Specifically, the method comprises the following steps:

1) the polybenzimidazole derivative is synthesized by easily available raw materials such as 3,3' -diaminobenzidine, glutaric acid, 1-bromopentane and the like through a two-step method, the reaction condition is mild, the reaction instrument is simple, the product is easy to separate and purify, and the yield is high;

2) the method can realize the sensing of two species of metal ions and nitroaromatic compounds by adjusting the alkylation degree of the polybenzimidazole derivative (namely adjusting the molar ratio of the polybenzimidazole intermediate to 1-bromopentane), and can realize the sensing of Cu under the indication of optical signals in the aspect of adsorption application²⁺Efficient cyclic adsorption;

3) the polybenzimidazole derivative disclosed by the invention has good solubility in dichloromethane, ethanol, dimethylformamide, dimethyl sulfoxide and acetonitrile, and can keep good solubility although the solubility in a part of organic solvents is reduced along with the increase of the alkylation degree of the polybenzimidazole derivative.

Drawings

FIG. 1 is an infrared spectrum of a polybenzimidazole derivative of example 1.

FIG. 2 is a nuclear magnetic resonance hydrogen spectrum of the polybenzimidazole derivative of example 1.

FIG. 3 is an SEM photograph of a polybenzimidazole derivative of example 1.

FIG. 4 shows the polybenzimidazole derivative complexed Cu of example 1²⁺Schematic representation of (a).

Detailed Description

The invention will be further explained and illustrated with reference to specific examples.

Example 1:

a polybenzimidazole derivative, the preparation method of which comprises the following steps:

1) adding 3mmol of 3,3' -diaminobenzidine and 3mmol of glutaric acid into a 50mL three-neck flask, adding 20mL of polyphosphoric acid (PPA), stirring at 160 ℃ for 2h, heating to 170 ℃ for reaction for 48h, cooling the reaction solution to room temperature, adjusting the pH to 9 with NaOH solution, performing suction filtration, respectively washing the filtered solid with hot water, ethyl acetate and ethanol for multiple times, and then placing the solid in a vacuum drying oven for drying at 50 DEG CAfter 24h, a polybenzimidazole intermediate is obtained

2) Adding 1mmol of polybenzimidazole intermediate and 1mmol of 1-bromopentane into 10mL of acetonitrile, adding 0.08g of NaOH, carrying out reflux reaction at 95 ℃ for 12h, carrying out reduced pressure distillation to remove the solvent, washing the solid obtained by distillation for multiple times with water, alternately eluting the product with dichloromethane and ethanol, collecting the organic phase, drying the organic phase in a vacuum drying oven at 40 ℃ for 24h, and obtaining the polybenzimidazole derivative (marked as SPBI, the number average molecular weight is 3500 g/mol-3800 g/mol).

The synthesis reaction of the polybenzimidazole derivative is as follows:

and (3) performance testing:

1) the infrared spectrum of the polybenzimidazole derivative is shown in figure 1, the nuclear magnetic resonance hydrogen spectrum is shown in figure 2, the SEM image is shown in figure 3, and Cu is complexed²⁺Is shown in fig. 4.

As can be seen from fig. 1: 3366cm^-1Is treated by N-H stretching vibration on a benzimidazole ring in a polybenzimidazole chain segment, and is 3030cm^-1The position is unsaturated C-H stretching vibration of benzene ring on benzimidazole ring, 2941cm^-1And 2871cm^-1Is in saturated C-H telescopic vibration of 1624cm^-1The part is C-N telescopic vibration on an imidazole ring, 1570cm^-1、1532cm^-1And 1451cm^-1The vibration of benzene ring skeleton is 1278cm^-1Is positioned at 866cm under C-N telescopic vibration on an imidazole ring^-1And 803cm^-1In the formula (I) is 1,2, 4-trisubstituted benzene ring, 724cm^-1Is a plurality of-CH₂Deformation vibrations in the linear chain.

The nuclear magnetic resonance hydrogen spectrum of fig. 2 was analyzed by the following resolution:

¹H NMR(DMSO-d₆,400MHz)：δ＝0.69～0.90(m,H_k,-CH₃),1.10～1.32(m,H_i,H_j,-CH₂-), 1.33～1.37(m,H_f',-CH₂-),1.57～1.75(m,H_h,-CH₂-),2.26～2.43(m,H_f,H_g',-CH₂-),2.94～3.11(m, H_e,H_e',-CH₂-),4.08～4.28(m,H_g,-CH₂-),6.56(d,J＝8.0Hz,H_k',Ar-H),6.72(d,J＝8.0Hz,H_j', Ar-H),6.87(s,H_l',Ar-H),7.01～7.29(m,H_d',H_i'H_h',-NH-,-COOH),7.36～7.50(m,H_a,H_a',Ar-H), 7.52～7.65(m,H_b,H_b',Ar-H),7.69～7.90(m,H_c,H_c',Ar-H),12.26(b,H_d,-NH-)。

as can be seen from fig. 3: the surface appearance of the polybenzimidazole derivative is a fluffy coral-shaped structure, namely a porous structure.

2) Adsorption performance:

a) the preparation and first adsorption application of the adsorption solution are as follows: 0.0177g of polybenzimidazole derivative was dissolved in 50mL of an ethanol/dichloromethane (v/v ═ 1/1) solution to obtain an adsorption solution, and 0.0195g of CuSO was added thereto₄·5H₂Dissolving O in 5mL of water, dropwise adding an adsorption solution after the O is completely dissolved, completely coordinating with metal ions by means of a change indication material of an ultraviolet-visible absorption spectrum in a system, spin-drying the solvent, and washing free Cu in the solid for multiple times by using deionized water²⁺Centrifuging the washing solution, taking out supernatant, fixing volume to obtain solution to be tested, and preparing Cu²⁺The standard solution is used for making a standard curve, detecting the concentration of the solution to be detected in the sample through Atomic Absorption Spectroscopy (AAS), and calculating the adsorption rate;

b) multiple cycle adsorption application: and (2) treating the coordinated solid by using an HCl solution with the pH value of 2 and an EDTA solution, stirring for 30min, filtering to obtain a polybenzimidazole derivative solid, neutralizing acid remained on the surface of the solid by using an NaOH solution with the pH value of 8, leaching by using deionized water to ensure that the pH value of the system is 7, recovering the N atom participating in coordination in the material to the original state, obtaining the recyclable adsorption material, and continuing the adsorption test.

Through testing, the polybenzimidazole adsorbing material is used for Cu²⁺The first adsorption rate of the adsorbent reaches 96.81%, and the adsorption rate can still be kept above 80% after 5 times of circulation.

3) Dissolution property:

the polybenzimidazole derivatives were dispersed in dichloromethane, ethanol, dimethylformamide, dimethylsulfoxide and acetonitrile, respectively, and tested for solubility.

The polybenzimidazole derivative has good solubility in dichloromethane, ethanol, dimethylformamide, dimethyl sulfoxide and acetonitrile.

Example 2:

a polybenzimidazole derivative, the preparation method of which comprises the following steps:

1) adding 3mmol of 3,3' -diaminobenzidine and 3mmol of glutaric acid into a 50mL three-neck flask, adding 20mL of polyphosphoric acid (PPA), stirring at 160 ℃ for 2h, heating to 170 ℃ for reaction for 48h, cooling the reaction solution to room temperature, adjusting the pH to 9 with NaOH solution, carrying out suction filtration, respectively filtering with hot water, ethyl acetate and ethanol for multiple times to obtain solids, and then placing in a vacuum drying oven for drying at 50 ℃ for 24h to obtain a polybenzimidazole intermediate;

2) adding 1mmol of polybenzimidazole intermediate and 0.1mmol of 1-bromopentane into 10mL of acetonitrile, adding 0.008g of NaOH, carrying out reflux reaction at 95 ℃ for 18h, carrying out reduced pressure distillation to remove the solvent, washing the distilled solid for multiple times with water, alternately leaching the product with dichloromethane and ethanol, collecting the organic phase, carrying out spin drying, and drying in a vacuum drying oven at 40 ℃ for 24h to obtain the polybenzimidazole derivative (with the number average molecular weight of 2500 g/mol-2700 g/mol).

Tests prove that the polybenzimidazole derivative prepared by the embodiment also has a porous structure, has good solubility in dichloromethane, ethanol, dimethylformamide, dimethyl sulfoxide and acetonitrile, and can be used for treating Cu²⁺The first adsorption rate of the adsorbent reaches 75.07%, and the adsorption rate can still be maintained above 57.74% after 5 times of circulation.

Example 3:

a polybenzimidazole derivative, the preparation method of which comprises the following steps:

1) adding 3mmol of 3,3' -diaminobenzidine and 3mmol of glutaric acid into a 50mL three-neck flask, adding 20mL of polyphosphoric acid (PPA), stirring at 160 ℃ for 2h, heating to 170 ℃ for reaction for 48h, cooling the reaction solution to room temperature, adjusting the pH to 9 with NaOH solution, carrying out suction filtration, respectively filtering with hot water, ethyl acetate and ethanol for multiple times to obtain solids, and then placing in a vacuum drying oven for drying at 50 ℃ for 24h to obtain a polybenzimidazole intermediate;

2) adding 1mmol of polybenzimidazole intermediate and 5mmol of 1-bromopentane into 10mL of acetonitrile, adding 0.4g of NaOH, carrying out reflux reaction at 95 ℃ for 24 hours, carrying out reduced pressure distillation to remove the solvent, washing the solid obtained by distillation for multiple times with water, alternately leaching the product with dichloromethane and ethanol, collecting the organic phase, carrying out spin drying, and placing in a vacuum drying oven for drying at 40 ℃ for 24 hours to obtain the polybenzimidazole derivative (the number average molecular weight is 5200 g/mol-5600 g/mol).

Tests prove that the polybenzimidazole derivative prepared by the embodiment also has a porous structure, has good solubility in dichloromethane, ethanol, dimethylformamide, dimethyl sulfoxide and acetonitrile, and can be used for treating Cu²⁺The first adsorption rate of the adsorbent reaches 73.43 percent, and the adsorption rate can still be kept above 52.78 percent after 5 times of circulation.

Example 4:

a polybenzimidazole derivative, the preparation method of which comprises the following steps:

1) adding 3mmol of 3,3' -diaminobenzidine and 3mmol of glutaric acid into a 50mL three-neck flask, adding 20mL of polyphosphoric acid (PPA), stirring at 160 ℃ for 2h, heating to 170 ℃ for reaction for 48h, cooling the reaction solution to room temperature, adjusting the pH to 9 with NaOH solution, carrying out suction filtration, respectively filtering with hot water, ethyl acetate and ethanol for multiple times to obtain solids, and then placing in a vacuum drying oven for drying at 50 ℃ for 24h to obtain a polybenzimidazole intermediate;

2) adding 1mmol of polybenzimidazole intermediate and 3mmol of 1-bromopentane into 10mL of acetonitrile, adding 0.24g of NaOH, refluxing and reacting at 95 ℃ for 20h, distilling under reduced pressure to remove the solvent, washing the distilled solid for multiple times by using water, alternately leaching the product by using dichloromethane and ethanol, collecting the organic phase, spin-drying, and drying in a vacuum drying oven at 40 ℃ for 24h to obtain the polybenzimidazole derivative (the number-average molecular weight is 4100 g/mol-4300 g/mol).

Tests prove that the polybenzimidazole derivative prepared by the embodiment also has a porous structure, has good solubility in dichloromethane, ethanol, dimethylformamide, dimethyl sulfoxide and acetonitrile, and can be used for treating Cu²⁺The first adsorption rate of the adsorbent reaches 74.52%, and the adsorption rate can still be kept above 53.68% after 5 times of circulation.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.