Preparation method and application of high-coordination lignin conductive hydrogel
By using chloroalkylamide bitodental coordination precursor in conductive hydrogels to coordinate with hydroxyalkyllignin and coordinate with lithium ions, the problem of large interface contact resistance of lignin molecules and metal ions is solved, and a high conductivity and stable conductive hydrogel is achieved.
Patent Information
- Application Number
- CN202510139941.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-08
- Publication Date
- 2025-04-18
Smart Images
Figure CN119842100A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of conductive hydrogels, and in particular to a preparation method and application of a highly coordinated lignin conductive hydrogel. Background Art
[0002] Flexible wearable electronic devices are a product that combines electronic devices with textiles or other wearable materials, showing great application prospects in the fields of health, medicine, sports, etc. Among them, conductive hydrogel is a new type of hydrogel that organically combines a flexible polymer matrix and a conductive medium. It has multiple properties such as stretchability, conductivity, stimulus responsiveness and strain sensitivity, and is the best choice for current flexible wearable devices.
[0003] Conductive hydrogel is mainly composed of a hydrogel network and a conductive polymer. Among them, the conductive polymer can convert external signals such as heat, magnetism, and force into electrical signals, and is the core component of the conductive hydrogel. The conductive hydrogel prepared by direct blending of rigid carbon or metal conductive polymers and flexible polymer matrices in the early stage can no longer meet market demand due to poor electrochemical and mechanical properties. At present, conductive hydrogels are obtained by mixing lignin materials with metal ions, or by replacing part of the monomers with lignin through interpenetrating polymer networks or polymerization. However, the conductive polymers obtained by direct blending of lignin molecules and metal ions have problems such as large interface contact resistance, high energy barriers, and poor interface compatibility, which reduce the conductivity of the hydrogel. Summary of the invention
[0004] The present invention aims to solve the problems of large interface contact resistance, high energy barrier and poor interface compatibility in the conductive polymer obtained by directly blending lignin molecules with metal ions in the prior art, and provides a preparation method and application of a highly coordinated lignin conductive hydrogel.
[0005] To achieve the above object, the technical solution of the present invention is:
[0006] First, a method for preparing a highly coordinated lignin conductive hydrogel is provided, comprising the steps of:
[0007] (1) Preparation of bidentate coordination precursor: an aminothiazole compound is reacted with a chloroalkylacyl chloride to obtain a chloroalkylamide bidentate coordination precursor;
[0008] (2) Modification of lignin: reacting lignin with lactone to obtain hydroxyalkyl lignin derivatives;
[0009] (3) Modification of modified lignin: the hydroxyalkyl lignin derivative prepared in step (2) and the chloroalkylamide bidentate coordination precursor prepared in step (1) are subjected to a substitution reaction under alkaline conditions to prepare a modified lignin with bidentate coordination modification;
[0010] (4) Preparation of lignin conductive hydrogel: Add bidentate modified lignin into polyvinyl alcohol solution, mix well, stir in the dark and pour into a mold, soak the mold and hydrogel in lithium chloride ion solution to prepare high coordination lignin conductive hydrogel.
[0011] In one embodiment, the aminothiazole compound is 2-aminothiazole, and the reaction formula of step (1) is formula (1):
[0012]
[0013] In the formula, n=1, 2, 3.
[0014] In one embodiment, the aminothiazole compound is 2-aminobenzothiazole, and the reaction formula of step (1) is formula (2):
[0015]
[0016] In the formula, n=1, 2, 3.
[0017] In one embodiment, the ether reagent is one of methyl tert-butyl ether, tetrahydrofuran or dioxane.
[0018] In one embodiment, step (2) comprises weighing organic lignin into acetonitrile, adding lactone and acid catalyst to the lignin-acetonitrile, raising the reaction temperature to 60-80° C. and stirring the reaction for 12-16 hours, cooling the reaction to room temperature after the reaction is completed, and adding the reaction solution dropwise into distilled water to produce a large amount of yellow flocculent precipitate, thereby preparing a hydroxyalkyl lignin derivative.
[0019] In one embodiment, the acid catalyst is one of sulfuric acid, methanesulfonic acid or phosphoric acid.
[0020] In one embodiment, step (3) comprises weighing a hydroxyalkyl lignin derivative, adding a strong base, the chloroalkylamide bidentate coordination precursor prepared in step (1) and tetrahydrofuran to prepare a reaction system, heating the reaction system to 50-66° C. and stirring the reaction system for 16-24 hours. After the reaction is completed, cooling the reaction system to room temperature to obtain a crude modified lignin product with bidentate coordination modification.
[0021] Secondly, the present invention also provides an application of a high-coordination lignin conductive hydrogel, and the high-coordination lignin conductive hydrogel prepared as above is used as a flexible wearable device.
[0022] Beneficial effect: the present invention coordinates a chloroalkylamide bidentate coordination precursor synthesized by reacting an aminothiazole compound with an alkyl chloride with hydroxyalkyl lignin to obtain a modified lignin with a strong coordination effect, which coordinates with lithium ions to form a stable complex, thereby obtaining a highly conductive ion-conductive hydrogel.
[0023] In order to make the above features and advantages of the invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is the infrared spectrum of the product 2-chloro-N-thiazole-2-methylacetamide in step (1) of Example 1 of the present invention.
[0025] Figure 2 The mass spectrum of the product 2-chloro-N-thiazole-2-methylacetamide in step (1) of Example 1 of the present invention.
[0026] Figure 3 The NMR of the product 2-chloro-N-thiazole-2-methylacetamide in step (1) of Example 1 of the present invention is 1 H spectrum.
[0027] Figure 4 The NMR of the product 2-chloro-N-thiazole-2-methylacetamide in step (1) of Example 1 of the present invention is 13 C spectrum.
[0028] Figure 5 This is the infrared spectrum of the hydroxyalkyl lignin derivative produced in step (2) of Example 1 of the present invention.
[0029] Figure 6 This is the infrared spectrum of the bidentate-modified modified lignin of step (3) in Example 1 of the present invention.
[0030] Figure 7 This is a physical picture of the highly coordinated lignin conductive hydrogel prepared in Example 1 of the present invention.
[0031] Figure 8 This is a physical comparison diagram of the high-coordination lignin conductive hydrogel prepared in Example 1 of the present invention and a blank hydrogel.
[0032] Fig. 9 This is a diagram of a light bulb experiment using the highly coordinated lignin conductive hydrogel prepared in Invention Example 1 as the conductive medium. DETAILED DESCRIPTION
[0033] In order to make the purpose and technical solution of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment 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] First, the present invention provides a method for preparing a high-coordination lignin conductive hydrogel, comprising the following steps:
[0035] (1) Preparation of bidentate ligand precursors;
[0036] The aminothiazole compound is reacted with chloroalkyl acid chloride under alkaline conditions to prepare a chloroalkyl amide bidentate coordination precursor.
[0037] The specific steps include:
[0038] In an environment with nitrogen as protective gas, 50-100 mmol of an aminothiazole compound is weighed into a container, and an ether reagent is added as a solvent to prepare a 0.1-0.5 mol / L aminothiazole solution.
[0039] The aminothiazole compound may be one of 2-aminothiazole or 2-aminobenzothiazole.
[0040] The ether reagent may be one of methyl tert-butyl ether, tetrahydrofuran or dioxane.
[0041] Add 1.5 to 2.0 times the mole number (relative to the aminothiazole compound) of an organic base to the aminothiazole solution to form a reaction system, control the temperature of the reaction system to 0 to 10°C, and slowly drop 1.0 to 1.2 times the mole number (relative to the aminothiazole compound) of chloroalkylacyl chloride to the reaction system, after the dropwise addition, raise the temperature of the reaction system to 25 to 50°C, continue stirring for 8 to 14 hours to complete the reaction, and obtain a complete reaction system.
[0042] The alkyl acyl chloride is one of chloroacetyl chloride, chloropropionyl chloride and chlorobutyryl chloride.
[0043] When the aminothiazole compound is 2-aminothiazole, the reaction formula is as shown in formula (1):
[0044]
[0045] In the formula, n=1, 2, 3.
[0046] When the aminothiazole compound is 2-aminobenzothiazole, the reaction formula is as shown in formula (2):
[0047]
[0048] In the formula, n=1, 2, 3.
[0049] 50 mL of saturated ammonium chloride solution was added to the complete reaction system to quench the reaction, and then 100-200 mL of water was added and separated to obtain an aqueous phase and an organic phase.
[0050] The aqueous phase was extracted three times with 50 mL of ethyl acetate, the organic phase obtained by extraction was mixed with the organic phase separated in step S13, the organic phase was washed with 1-2 mL of saturated sodium chloride and dried with anhydrous sodium sulfate for 30 min, and concentrated under reduced pressure to remove the solvent. Then, the product chloroalkylamide bidentate coordination precursor was prepared by recrystallization with ethyl acetate, and the yield was 83%-94%.
[0051] (2) Modification of lignin;
[0052] Lignin is reacted with lactone to obtain a new type of hydroxyalkyl lignin derivative. Due to the introduction of a new alkyl chain, the steric hindrance is reduced, which greatly improves the nucleophilic property of the hydroxyl group.
[0053] The specific steps include:
[0054] Weigh small molecular weight organic lignin into acetonitrile to make the concentration of lignin 0.1-0.3 g / mL.
[0055] Add 0.5 to 0.8 times the mass (relative to lignin) of lactone to lignin-acetonitrile, add 1 to 2 drops of acid catalyst, raise the reaction temperature to 60 to 80° C. and stir the reaction for 12 to 16 hours. The acid catalyst is one of sulfuric acid, methanesulfonic acid or phosphoric acid.
[0056] After the reaction is finished, the mixture is cooled to room temperature and the reaction solution is added dropwise to distilled water to produce a large amount of yellow flocculent precipitates, thereby obtaining a hydroxyalkyl lignin derivative. The volume of the distilled water is 8 to 12 times that of the acetonitrile.
[0057] The lactone may be delta-valerolactone
[0058] The reaction formula for modifying lignin by δ-valerolactone is shown in formula (3):
[0059]
[0060] In other embodiments, the lactone may also be caprolactone or the like.
[0061] (3) Modification of modified lignin;
[0062] The hydroxyalkyl lignin derivative prepared in step (2) and the chloroalkylamide bidentate coordination precursor prepared in step (1) are subjected to a substitution reaction under alkaline conditions to prepare a bidentate coordination modified lignin.
[0063] The specific steps include:
[0064] A certain amount of hydroxyalkyl lignin derivative is weighed, and a strong base, the chloroalkylamide bidentate coordination precursor prepared in step (1) and tetrahydrofuran are added to prepare a reaction system. The reaction system is heated to 50-66° C. and stirred for reaction for 16-24 hours. After the reaction is completed, the system is cooled to room temperature to obtain a crude bidentate coordinated modified lignin product.
[0065] The strong base is one of potassium tert-butoxide, sodium tert-butoxide or sodium ethoxide.
[0066] The molar ratio of the hydroxyalkyl lignin to the strong base is 1:10-15; the molar ratio of the hydroxyalkyl lignin to the chloroalkylamide bidentate coordination precursor is 1:5-8; and the concentration of the hydroxyalkyl lignin in the tetrahydrofuran is 0.02-0.1 g / mL.
[0067] 10 mL of saturated ammonium chloride solution was added to the crude modified lignin modified by bidentate coordination effect to quench the reaction, and the solid after filtration was washed with 5 mL of methanol for multiple times and then centrifuged to remove methanol to prepare modified lignin modified by bidentate coordination effect.
[0068] When the aminothiazole compound in step (1) is 2-aminothiazole, the reaction formula of step (3) is as shown in formula (4):
[0069]
[0070] In the formula, n=1, 2, 3.
[0071] When the aminothiazole compound in step (1) is 2-aminobenzothiazole, the reaction formula of step (3) is as shown in formula (5):
[0072]
[0073] In the formula, n=1, 2, 3.
[0074] (4) Preparation of lignin conductive hydrogel;
[0075] The modified lignin modified with bidentate coordination is added to the polyvinyl alcohol solution, mixed evenly, stirred in the dark and poured into the mold, the mold and the hydrogel are frozen at -20℃ for 24 hours, taken out and thawed for 2 hours, repeated three times and immersed in the lithium chloride ion solution for 12 hours, the modified lignin modified with bidentate coordination effect forms coordination bonds with lithium ions to form a stable complex, thereby preparing a high-coordination lignin conductive hydrogel.
[0076] Secondly, the present invention also provides an application of a high-coordination lignin conductive hydrogel, and the high-coordination lignin conductive hydrogel prepared as above is used as a flexible wearable device.
[0077] The following is a further description with reference to specific embodiments.
[0078] Example 1
[0079] This embodiment uses 2-aminothiazole to synthesize a chloroalkylamide bidentate coordination precursor, and then modifies the modified lignin to prepare a lignin conductive hydrogel. The steps include:
[0080] (1) Preparation of bidentate ligand precursors;
[0081] Select a 250mL single-mouth round-bottom flask and a stirring bar of an appropriate size, use an analytical balance to weigh 3.004g of 2-aminothiazole and add it to the round-bottom flask. In a fume hood, use a clean measuring cylinder to measure 120mL of dried tetrahydrofuran solution and add it to the round-bottom flask to prepare a 2-aminothiazole solution.
[0082] Under a nitrogen atmosphere, add 5.42 mL of triethylamine to the 2-aminothiazole solution, and stir in an ice-water bath at 0-10°C for 5 min until dissolved; after dissolution, draw 2.63 mL of chloroacetyl chloride with a 5 mL syringe and slowly add it dropwise to the flask; after the addition is completed, slowly raise the temperature to room temperature, stir the reaction at room temperature for 12 h until the reaction is complete, and at the end of the reaction, an orange-yellow liquid is obtained.
[0083] The orange-yellow liquid was cooled to 0°C, quenched by adding 10 mL of saturated ammonium chloride solution, and then the reaction solution was transferred to a 250 mL separatory funnel, 50 mL of distilled water was added, and extracted three times with ethyl acetate (50 mL×3), 2 mL of saturated sodium chloride solution was added to the ethyl acetate layer, and the layers were shaken to separate, and the ethyl acetate layer was collected in a clean beaker and added with anhydrous sodium sulfate for drying; after drying, the solvent was removed by rotary evaporator to obtain a brown-yellow solid as a crude product, and ethyl acetate was used as a recrystallization solvent to recrystallize and purify the brown-yellow solid in the flask to obtain orange-yellow crystals, which were 4.24 g of 2-chloro-N-thiazole-2-methylacetamide, with a yield of 80%.
[0084] The melting point of the product 2-chloro-N-thiazole-2-methylacetamide was tested, and the test result was 165.8-167.4°C. The product 2-chloro-N-thiazole-2-methylacetamide was subjected to infrared spectroscopy, high-resolution mass spectrometry, and nuclear magnetic resonance spectroscopy. 1 H spectroscopy and NMR 13 C spectrum characterization test, test results see Figures 1 to 4 The characterization data are:
[0085] IR(KBr,cm -1 ): ν=3186, 2949, 1701, 1580, 1163, 717cm -1 .
[0086] HRMS [C5H6ClN2OS + ][ESI + ]:[M+H + ]=176.9884, found m / z=176.9885.
[0087] 1 H NMR (CDCl3, 400MHz): δ = 10.99 (s, 1H), 7.53 (s, 1H), 7.06 (s, 1H), 4.28 (s, 2H) ppm.
[0088] 13 C NMR (CDCl3, 100MHz): δ=164.1, 157.9, 137.4, 114.5, 42.0ppm.
[0089] (2) Modification of lignin;
[0090] Weigh 2.00 g of organic lignin, pour it into a 100 mL round-bottom flask, add 20 mL of acetonitrile and ultrasonically dissolve it, then add 1.82 g of δ-valerolactone, and then add 1 drop of methanesulfonic acid. Place it in a 70 ° C oil bath and add a magnetic reflux reaction for 14 hours.
[0091] After the reaction was stopped and cooled, the reaction solution was slowly added dropwise into distilled water to produce flocculent precipitation. Each 1 mL of reaction solution was added dropwise into 10 mL of water. After suction filtration, 2.9 g of yellow solid, i.e., hydroxyalkyl lignin derivative, was obtained with a yield of 76%. The infrared spectrum characterization diagram is shown in the figure below. Figure 5 shown.
[0092] (3) Modification of modified lignin;
[0093] Select a 150mL round-bottom flask, select a stirrer of appropriate size, accurately weigh 2.0g of hydroxyalkyl lignin derivative with an analytical balance, weigh 1.65g of 2-chloro-N-thiazole-2-methylacetamide, and 1.26g of sodium tert-butoxide in the flask, and in a fume hood, use a clean measuring cylinder to measure 20mL of dried tetrahydrofuran solution and add it to the round-bottom flask. Stir and react at 60℃ for 18h, use a rotator to spin off the solvent, add 10mL of saturated ammonium chloride solution to quench, use a vacuum filter to filter, collect the filtered product in a centrifuge tube, add 5mL of methanol, vortex centrifuge and wash twice, filter again, dry and weigh to obtain 3.12g of bidentate modified lignin, and its infrared characterization is shown in the figure below. Figure 6 shown.
[0094] (4) Preparation of lignin conductive hydrogel;
[0095] The modified lignin modified with bidentate coordination is added to the polyvinyl alcohol solution, mixed evenly, stirred in the dark and poured into the mold, the mold and the hydrogel are frozen at -20℃ for 24 hours, taken out and thawed for 2 hours, repeated three times and immersed in the lithium chloride ion solution for 12 hours, the modified lignin modified with bidentate coordination effect forms coordination bonds with lithium ions to form a stable complex, thereby preparing a high-coordination lignin conductive hydrogel.
[0096] Figure 7 The actual picture shows the highly coordinated lignin conductive hydrogel. Figure 8 The picture shows the actual comparison between the highly coordinated lignin conductive hydrogel and the blank hydrogel. It is used as a conductive medium in the light bulb experiment, such as Fig. 9 As shown, it can be seen that the product prepared by the present invention has conductive properties.
[0097] In summary, the present invention coordinates a chloroalkylamide bidentate coordination precursor synthesized by reacting an aminothiazole compound with an alkyl chloride with hydroxyalkyl lignin to obtain a modified lignin with a strong coordination effect, which coordinates with lithium ions to form a stable complex, thereby obtaining a highly conductive ion-conductive hydrogel.
[0098] Although the present invention has been illustrated and described in detail by means of preferred embodiments, the present invention is not limited to the disclosed examples and other variations may be derived therefrom by those skilled in the art without departing from the scope of protection of the present invention.
Claims
1. A method for preparing a highly coordinated lignin conductive hydrogel, characterized in that: Includes steps: (1) Preparation of bidentate coordination precursor: an aminothiazole compound is reacted with a chloroalkylacyl chloride to obtain a chloroalkylamide bidentate coordination precursor; (2) Modification of lignin: reacting lignin with lactone to obtain hydroxyalkyl lignin derivatives; (3) Modification of modified lignin: the hydroxyalkyl lignin derivative prepared in step (2) and the chloroalkylamide bidentate coordination precursor prepared in step (1) are subjected to a substitution reaction under alkaline conditions to prepare a modified lignin with bidentate coordination modification; (4) Preparation of lignin conductive hydrogel: Add bidentate modified lignin into polyvinyl alcohol solution, mix well, stir in the dark and pour into a mold, soak the mold and hydrogel in lithium chloride ion solution to prepare high coordination lignin conductive hydrogel.
2. The method for preparing a highly coordinated lignin conductive hydrogel according to claim 1, characterized in that: The aminothiazole compound is 2-aminothiazole, and the reaction formula of step (1) is formula (1): Wherein, n=1, 2, 3; RO-R' is an ether reagent.
3. The method for preparing a highly coordinated lignin conductive hydrogel according to claim 1, characterized in that: The aminothiazole compound is 2-aminobenzothiazole, and the reaction formula of step (1) is formula (2): Wherein, n=1, 2, 3; RO-R' is an ether reagent.
4. The method for preparing a highly coordinated lignin conductive hydrogel according to claim 2 or 3, characterized in that: The ether reagent is one of methyl tert-butyl ether, tetrahydrofuran or dioxane.
5. The method for preparing a highly coordinated lignin conductive hydrogel according to claim 1, characterized in that: Step (2) comprises weighing organic lignin into acetonitrile, adding lactone and acid catalyst to the lignin-acetonitrile, raising the reaction temperature to 60-80° C. and stirring the reaction for 12-16 hours, cooling the reaction to room temperature after the reaction is completed, and dropping the reaction solution into distilled water to produce a large amount of yellow flocculent precipitate, thereby preparing a hydroxyalkyl lignin derivative.
6. The method for preparing a highly coordinated lignin conductive hydrogel according to claim 5, characterized in that: The acid catalyst is one of sulfuric acid, methanesulfonic acid or phosphoric acid.
7. The method for preparing a highly coordinated lignin conductive hydrogel according to claim 1, characterized in that: Step (3) comprises weighing a hydroxyalkyl lignin derivative, adding a strong base, the chloroalkylamide bidentate coordination precursor prepared in step (1) and tetrahydrofuran to prepare a reaction system, heating the reaction system to 50 to 66° C. and stirring the reaction system for 16 to 24 hours. After the reaction is completed, cooling the reaction system to room temperature to obtain a crude bidentate coordinated modified lignin product.
8. An application of a high coordination lignin conductive hydrogel, characterized in that: The lignin conductive hydrogel as described in any one of claims 1 to 7 is applied to flexible wearable devices.