Bis-cyano phosphine oxide monomer as well as preparation method and application thereof

Abstract

The invention provides a dicyanophosphine oxide monomer, the chemical name of the dicyanophosphine oxide monomer is 4-vinyl benzyl-bis (2-cyanoethoxy methyl) phosphine oxide, and the specific structural formula of the dicyanophosphine oxide monomer is imgabs0 #. The specific preparation method comprises the following steps: dissolving 4-vinylbenzyl-bis (hydroxymethyl) phosphine oxide in an alkali solution, slowly dropwise adding acrylonitrile at 0-5 DEG C, slowly recovering to room temperature after dropwise adding, continuously reacting, adjusting the pH value of a system to 6-7 by using hydrochloric acid after the reaction is finished, adding dichloromethane to extract a product, carrying out rotary evaporation on extract liquor to remove a solvent so as to obtain a viscous liquid, and drying the viscous liquid, thereby obtaining the product. The compound is 4-vinyl benzyl-bis (2-cyanoethoxy methyl) phosphine oxide. The 4-vinyl benzyl-bis (2-cyanoethoxy methyl) phosphine oxide prepared by the invention can be used in a battery electrolyte, and has good conductivity and stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical synthesis, and particularly relates to a dicyano phosphine oxide monomer, a preparation method thereof and an application thereof. Background Art

[0002] Nitrile electrolytes or cyano polymer electrolytes have high dielectric constants, high anodic oxidation potentials and strong coordination abilities. However, the cathode stability of cyano polymer electrolytes is poor, and the compatibility between polymer electrolytes and lithium electrodes or lithiated graphite is poor, which limits their further applications. Two strategies can improve the performance of cyano polymer electrolytes: (1) using additives such as vinylene carbonate and fluoroethylene carbonate in polymer electrolytes to form an effective solid electrolyte interface (SEI); (2) using ultra-concentrated salt solutions, which will form a salt-derived surface film on graphite electrodes. In addition to the above strategies, solid polymer electrolytes exhibit low ionic conductivities at room temperature without any small molecule plasticizers. For most existing electrolyte systems, especially polyacrylonitrile, it is difficult to obtain self-supporting films. By copolymerizing with monomers having different functional groups, the structure of the polymer can be optimized to further improve ionic conductivity, mechanical strength and processing performance. Since the CN-Li interaction may be the main reason for the conductivity of polyacrylonitrile, it is particularly important to develop new polymers with cyano groups to improve the conductivity of polymer electrolytes.

[0003] Further improving the performance of cyano polymer electrolytes by designing new compounds, compounding with other functional polymers and / or additives makes cyano electrolytes more likely to have potential applications in high energy density batteries (including lithium-sulfur batteries and lithium-air batteries). Summary of the Invention

[0004] In view of this, the present invention provides a dicyano phosphine oxide monomer, a preparation method thereof and an application thereof.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A dicyano phosphine oxide monomer, the chemical name of the dicyano phosphine oxide monomer is 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide, and the specific structural formula is as follows: .

[0006] A preparation method of the above-mentioned dicyano phosphine oxide monomer is as follows: Dissolve 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide in an alkali solution, slowly dropwise add acrylonitrile at 0-5 °C, and slowly return to room temperature to continue the reaction after the addition is completed. After the reaction is completed, adjust the pH of the system to 6-7 with hydrochloric acid, add dichloromethane to extract the product, and the extract is evaporated to remove the solvent by rotary evaporation to obtain a viscous liquid, namely 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide.

[0007] The specific reaction formula is as follows: 。

[0008] Further, the alkali solution includes sodium hydroxide solution, potassium hydroxide solution, and sodium carbonate solution; the concentration of the alkali solution is 0.2 wt% - 2 wt%.

[0009] Further, the concentration of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide in the mixed solution of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide and the alkali solution is 20 wt% - 50 wt%.

[0010] Further, the molar ratio of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide to acrylonitrile is 1:(2 - 6).

[0011] Further, the reaction time at room temperature is 12 h - 36 h.

[0012] Further, the concentration of the hydrochloric acid is 6 mol / L.

[0013] Further, the rotary evaporation conditions are: rotation speed 30 - 50 rpm, temperature 10 - 20 °C.

[0014] Further, the addition amount of dichloromethane is 2 - 10 times the mass of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide.

[0015] Application of the above-mentioned dicyano phosphine oxide monomer in battery electrolytes.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide prepared by the present invention can be used to prepare battery electrolytes, solving the problems of poor cathode stability of cyanopolymer electrolytes and poor compatibility between polymer electrolytes and lithium electrodes or lithiated graphite; the prepared battery electrolyte has good conductivity (3.31×10 -5 S / m, 50 °C) and good stability (4.85 V vs. Li / Li + ). In addition, the provided preparation method is simple and the conditions are mild. It provides a new idea for cyanopolymer electrolytes. Description of the Drawings

[0017] Figure 1 1H NMR spectrum of 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide prepared according to the present invention.

[0018] Figure 2 13C NMR spectrum of 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide prepared according to the present invention.

[0019] Figure 3 31P NMR spectrum of 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide prepared according to the present invention.

[0020] Figure 4 IR spectrum of 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide prepared according to the present invention.

[0021] Figure 5 1H NMR spectrum of poly(4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide) prepared according to the present invention.

[0022] Figure 6 13C NMR spectrum of poly(4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide) prepared according to the present invention.

[0023] Figure 7 31P NMR spectrum of poly(4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide) prepared according to the present invention.

[0024] Figure 8 EIS curve of poly(4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide) / lithium bis(trifluoromethanesulfonyl)imide polymer electrolyte membrane prepared according to the present invention at 50 °C.

[0025] Figure 9 LSV curve of poly(4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide) / lithium bis(trifluoromethanesulfonyl)imide polymer electrolyte membrane prepared according to the present invention. Detailed implementation manners

[0026] The present invention will be further described in detail below with reference to specific examples, so that those skilled in the art can understand the present invention more clearly.

[0027] Sources and physicochemical parameters of key test materials: 4-Vinylbenzyl-bis(hydroxymethyl)phosphine oxide was prepared according to the preparation method in the literature "Synthesis and Properties of Reactive Polymers Containing Phosphorus-Carbon Bonds".

[0028] Example 1 This example provides a dicyano phosphine oxide monomer, and its preparation process is as follows: Dissolve 20 g of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide in 50 mL of a 0.5% sodium hydroxide solution. Slowly add 30 g of acrylonitrile dropwise at 3 °C. After the addition is complete, slowly return to room temperature and continue the reaction for 24 h. After the reaction is completed, adjust the pH of the system to 7 with 6 mol / L hydrochloric acid. Add 150 g of dichloromethane to extract the product. The extract is rotary evaporated to remove the solvent at a rotation speed of 30 rpm and a temperature of 15 °C to obtain 27.2 g of a colorless or light yellow viscous liquid, namely 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide. At this time, the yield of the product is measured to be 54.4% and the purity is 97%.

[0029] Example 2 This example provides a dicyano phosphine oxide monomer, and its preparation process is as follows: Dissolve 20 g of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide in 30 mL of a 1% sodium hydroxide solution. Slowly add 40 g of acrylonitrile dropwise at 5 °C. After the addition is complete, slowly return to room temperature and continue the reaction for 18 h. After the reaction is completed, adjust the pH of the system to 6 with 6 mol / L hydrochloric acid. Add 100 g of dichloromethane to extract the product. The extract is rotary evaporated to remove the solvent at a rotation speed of 40 rpm and a temperature of 20 °C to obtain 26.0 g of a colorless or light yellow viscous liquid, namely 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide. At this time, the yield of the product is measured to be 43.3% and the purity is 95%.

[0030] Example 3 This example provides a dicyano phosphine oxide monomer, and its preparation process is as follows: Dissolve 20 g of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide in 80 mL of a 0.2% potassium hydroxide solution. Slowly add 20 g of acrylonitrile dropwise at 0 °C. After the addition is complete, slowly return to room temperature and continue the reaction for 12 h. After the reaction is completed, adjust the pH of the system to 6.5 with 6 mol / L hydrochloric acid. Add 60 g of dichloromethane to extract the product. The extract is rotary evaporated to remove the solvent at a rotation speed of 30 rpm and a temperature of 15 °C to obtain 23.8 g of a colorless or light yellow viscous liquid, namely 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide. At this time, the yield of the product is measured to be 59.5% and the purity is 92%.

[0031] Example 4 This example provides a dicyano phosphine oxide monomer, and its preparation process is as follows: Dissolve 20 g of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide in 50 mL of 1% sodium hydroxide solution. Slowly add 60 g of acrylonitrile dropwise at 2 °C. After the addition is complete, slowly return to room temperature and continue the reaction for 24 h. After the reaction is completed, adjust the pH of the system to 7 with 6 mol / L hydrochloric acid. Add 150 g of dichloromethane to extract the product. The extract is rotary evaporated at a rotation speed of 30 rpm and a temperature of 15 °C to remove the solvent, obtaining 28.4 g of a colorless or light yellow viscous liquid, namely 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide. At this time, the yield of the product is measured to be 35.5%, and the purity is 95%.

[0032] Example 5 This example provides a dicyano phosphine oxide monomer, and its preparation process is as follows: Dissolve 20 g of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide in 50 mL of 0.2% sodium hydroxide solution. Slowly add 40 g of acrylonitrile dropwise under the condition of 0 °C. After the addition is complete, slowly return to room temperature and continue the reaction for 36 h. After the reaction is completed, adjust the pH of the system to 6 with 6 mol / L hydrochloric acid. Add 100 g of dichloromethane to extract the product. The extract is rotary evaporated at a rotation speed of 30 rpm and a temperature of 15 °C to remove the solvent, obtaining 26 g of a colorless or light yellow viscous liquid, namely 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide. At this time, the yield of the product is measured to be 43.33%, and the purity is 94%.

[0033] Comparative Example 1 This comparative example provides a dicyano phosphine oxide monomer, and its preparation process is as follows: Dissolve 20 g of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide in 10 mL of 0.1% sodium hydroxide solution. Slowly add 10 g of acrylonitrile dropwise at 5 °C. After the addition is complete, slowly return to room temperature and continue the reaction for 48 h. After the reaction is completed, adjust the pH of the system to 7 with 6 mol / L hydrochloric acid. Add 30 g of dichloromethane to extract the product. The extract is rotary evaporated at a rotation speed of 30 rpm and a temperature of 15 °C to remove the solvent, and no product appears.

[0034] Furthermore, in order to understand the characteristics of the products prepared above, the following tests were also carried out: The prepared products were subjected to proton nuclear magnetic resonance, carbon nuclear magnetic resonance, phosphorus nuclear magnetic resonance, and infrared tests. The specific results are shown in Figures 1-4 . From Figures 1-4 it can be seen that the preparation method provided by this application has prepared the compound 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide.

[0035] Even further, in order to understand the performance of the prepared products, the following tests were also carried out: Weigh 10.00 g of 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide prepared in Example 1 into a 100 mL eggplant-shaped flask, add 40 mL of DMSO / water (1:1, v:v) mixed solution. After complete dissolution, add the initiator azobisisobutyronitrile (AIBN, 24.6 mg, 0.15 mmol). Continuously bubble argon at room temperature for 30 min, bubbling while stirring. After exhausting the gas, connect an argon bag, evacuate, and then fill with argon. Repeat the operation three times and then react in an oil bath at 70 °C for 24 h. After the reaction is completed, cool to room temperature, precipitate with ethanol, pour off the turbid liquid, dissolve the precipitate three times with DMSO-ethanol, and dry the obtained solid in a vacuum oven at 50 °C for 24 h to obtain 8.3 g of a white solid.

[0036] The prepared product was subjected to proton nuclear magnetic resonance, carbon nuclear magnetic resonance, and phosphorus nuclear magnetic resonance. The specific results are shown in Figures 5-7 . From Figures 5-7 it can be seen that the preparation method provided in this application has prepared the compound poly(4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide).

[0037] Poly(4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide) and lithium bis(trifluoromethanesulfonyl)imide were mixed at mass ratios of 9:1, 8:2, 7:3, 6:4, 5:5, and 4:6 respectively. After dissolving with N-methylpyrrolidone (NMP), it was poured into a polytetrafluoroethylene mold. First, dry it in a forced-air oven at 100 °C for 24 h, and then dry it in a vacuum oven at 100 °C for 24 h to obtain a solid electrolyte membrane. Assemble a stainless steel||electrolyte||stainless steel CR2025 coin cell in a glove box to measure its ionic conductivity (the results are shown in Table 1, Figure 8 ); Table 1 Ionic Conductivities of Electrolytes Prepared from Poly(4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide) and Lithium Bis(trifluoromethanesulfonyl)imide at Different Mass Ratios

[0038] From Table 1, Figure 8 it can be seen that: the polymer electrolyte membrane exhibits good lithium ion conductivity. As the concentration of the lithium salt increases, the ionic conductivity of the polymer electrolyte membrane gradually increases, and reaches a maximum value of 3.31×10 -5 S / m (50 °C) when the lithium salt concentration increases to 50%.

[0039] Furthermore, poly(4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide) and lithium bis(trifluoromethanesulfonyl)imide were assembled into a lithium foil||electrolyte||stainless steel CR2025 coin cell at a mass ratio of 5:5 respectively to measure its electrochemical stability (the results are shown in Figure 9 ).

[0040] From Figure 9It can be seen that the polymer electrolyte membrane has good electrochemical stability (4.85 V vs. Li / Li + ).

[0041] The above tests prove that the preparation method provided by this application can prepare 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide with a high purity (92% - 97%), and when the product is applied to the electrolyte of a battery, it has good conductivity and electrochemical stability, providing a new direction for preparing electrolytes from novel polymers with cyano groups.

[0042] In the present invention, specific raw materials not described are all existing substances and can be directly purchased from the market.

[0043] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A dicyanophosphine oxide monomer, characterized in that: The chemical name of the dicyanophosphine oxide monomer is 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide, and the specific structural formula is as follows: 。 2. A method for preparing the dicyanophosphine oxide monomer according to claim 1, characterized in that: The specific steps are as follows: dissolving 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide in an alkaline solution, slowly adding acrylonitrile at 0-5°C, slowly returning to room temperature to continue the reaction after the addition is completed, adjusting the pH of the system to 6-7 with hydrochloric acid after the reaction is completed, adding dichloromethane to extract the product, and removing the solvent by rotary evaporation to obtain a viscous liquid, namely 4-vinylbenzyl-bis(2-cyanoethoxymethyl)phosphine oxide.

3. The preparation method according to claim 2, characterized in that: The alkaline solution includes sodium hydroxide solution, potassium hydroxide solution and sodium carbonate solution; the concentration of the alkaline solution is 0.2wt%~2wt%.

4. The preparation method according to claim 2, characterized in that: The concentration of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide in the mixed solution of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide and the alkaline solution is 20wt%-50wt%.

5. The preparation method according to claim 2, characterized in that: The molar ratio of the 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide to acrylonitrile is 1:(2-6).

6. The preparation method according to claim 2, characterized in that: The room temperature reaction time is 12 h to 36 h.

7. The preparation method according to claim 2, characterized in that: The concentration of hydrochloric acid is 6 mol / L.

8. The preparation method according to claim 2, characterized in that: The amount of dichloromethane added is 2 to 10 times the mass of 4-vinylbenzyl-bis(hydroxymethyl)phosphine oxide.

9. The preparation method according to claim 2, characterized in that: The rotary evaporation conditions are: rotation speed 30-50 rpm, temperature 10-20 °C.

10. Use of the dicyanophosphine oxide monomer according to claim 1 in battery electrolyte.

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