Preparation method of cyanoethoxy alkyl derivative

Abstract

The invention discloses a preparation method of a cyanoethoxy alkyl derivative, which comprises the following steps: 1, mixing polyose and deionized water, heating to 50-70 DEG C, adding a boron reducing agent in batches, cooling to room temperature, adding a catalytic amount of inorganic base into the reaction liquid according to the molar ratio of the polyose to the inorganic base being (1: 0.01)-(1: 0.1), stirring and dissolving, and reacting at 30-45 DEG C for 2-3 hours to obtain the cyanoethoxy alkyl derivative; the preparation method comprises the following steps: adding polyose into a reaction kettle, dropwise adding acrylonitrile, and after dropwise adding, carrying out heat-preservation reaction according to a feeding molar ratio of the polyose to acrylonitrile of 1: 5-1: 9; the boron reducing agent is selected from one of sodium borohydride, potassium borohydride and sodium cyanoborohydride; and 2, after the reaction is finished, firstly adding a benign organic solvent into the reaction liquid for extraction, then adding an inert organic solvent into the organic phase, stirring for crystallization, and carrying out vacuum drying on the precipitated solid to obtain the product. The method has the advantages of few side reactions, simple post-treatment, high product yield and high purity, and is suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of nitrile compounds, and particularly to the preparation of cyanoethoxyalkane derivatives. Background Art

[0002] In recent years, with the booming development of the new energy industry, people's research on lithium battery electrolytes has been continuously deepened, and nitrile additives have attracted much attention from researchers due to their excellent performance.

[0003] For nitrile compounds, the bond energy of the carbon-nitrogen triple bond in their molecular structure is very high and is not easily oxidized. Nitriles have good stability on the positive electrode. At the same time, the cyano group has strong coordination ability and can bind to the active sites on the electrode surface, reducing the decomposition of the electrolyte by the electrode and enhancing the resistance of the electrolyte to the oxidation of the positive electrode. Therefore, the application of nitrile compounds in lithium battery electrolytes can effectively improve the cycle life of the electrolyte at high voltages.

[0004] Currently, the preparation method of such compounds usually uses polyols and excessive acrylonitrile as raw materials, and undergoes a Michael addition reaction under the catalysis of an alkali to prepare cyanoethoxyalkane derivatives. Specifically, reference can be made to patent application US2009 / 0112024. The technical problems existing in the above preparation process are as follows: some polyols are expensive, there are many side reactions, the reaction yield is low, and the product purity is low, which is not conducive to industrial production. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a new method for preparing cyanoethoxyalkane derivatives. This preparation method has a high yield, high purity, mild and controllable reaction, and is suitable for industrial production.

[0006] To solve the above problems, the technical solution adopted by the present invention is: a method for preparing cyanoethoxyalkane derivatives, comprising the following steps: First, mix polysaccharide and deionized water, heat to 50 °C to 70 °C, add a boron-based reducing agent in batches, and after cooling to room temperature, add a catalytic amount of inorganic base to the reaction solution. The molar ratio of polysaccharide to inorganic base is 1:0.01 to 1:0.1. After stirring and dissolving, at 30 °C to 45 °C, dropwise add acrylonitrile. After the addition is complete, keep the temperature for reaction. The molar ratio of polysaccharide to acrylonitrile in the feed is 1:5 to 1:9; the boron-based reducing agent is selected from one of sodium borohydride, potassium borohydride, and sodium cyanoborohydride.

[0007] Second, after the reaction is completed, first add a benign organic solvent to the reaction solution for extraction, and then add an inert organic solvent to the organic phase and stir for crystallization. The precipitated solid is dried in vacuo to obtain the product.

[0008] The above reaction schematic diagram is as follows: .

[0009] Further, in the aforementioned method for preparing a cyanoethoxy alkane derivative, the polysaccharide is selected from one of erythrose, arabinose, xylose, lyxose, mannose, sorbose, and galactose; the mass ratio of the polysaccharide to deionized water is 1:3 to 1:10.

[0010] Further, in the aforementioned method for preparing a cyanoethoxy alkane derivative, xylose is used as the polysaccharide; the molar ratio of xylose to acrylonitrile in the feed is 1:6 to 8.

[0011] Furthermore, in the aforementioned method for preparing a cyanoethoxy alkane derivative, the molar ratio of the polysaccharide to the boron-based reducing agent is 1:1.1 to 1:1.5.

[0012] Further, in the aforementioned method for preparing a cyanoethoxy alkane derivative, the boron-based reducing agent is selected from one of sodium borohydride and potassium borohydride.

[0013] Further, in the aforementioned method for preparing a cyanoethoxy alkane derivative, the inorganic base is selected from one of sodium hydroxide, potassium hydroxide, lithium hydroxide, and calcium hydroxide.

[0014] Further, in the aforementioned method for preparing a cyanoethoxy alkane derivative, the benign organic solvent is selected from one of diethyl ether, methyl tert-butyl ether, ethyl acetate, dimethyl carbonate, and dichloromethane, and the inert organic solvent is selected from one of n-hexane, cyclohexane, toluene, and carbon tetrachloride.

[0015] Further, in the aforementioned method for preparing a cyanoethoxy alkane derivative, the mass ratio of the benign organic solvent to the polysaccharide is 1:2 to 1:5, and the mass ratio of the benign organic solvent to the inert organic solvent is 1:1 to 1:4.

[0016] Furthermore, in the aforementioned method for preparing a cyanoethoxy alkane derivative, dimethyl carbonate is selected as the benign organic solvent, and cyclohexane is selected as the inert organic solvent.

[0017] Still further, in the aforementioned method for preparing a cyanoethoxy alkane derivative, the inert organic solvent is added in a dropwise manner, and the mass ratio of the benign organic solvent to the inert organic solvent is 1:2.

[0018] The advantages of the present invention are as follows: In the method for preparing a cyanoethoxy alkane derivative according to the present invention, the boron-based reducing agent can gently reduce sugar to sugar alcohol in water; by adding a catalytic amount of inorganic base, the nucleophilicity of the hydroxyl group of the polyhydric alcohol is enhanced, thereby promoting the forward progress of the acrylonitrile addition reaction. The entire preparation method has few side reactions, simple post-treatment, high product yield, and high purity, meeting the purity requirements of the additive for the lithium-ion battery electrolyte and being suitable for industrial production. Description of the Drawings

[0019] Figure 1 1H NMR spectrum of the product prepared in Example 3.

[0020] Figure 2 13C NMR spectrum of the product prepared in Example 3. Embodiment

[0021] The preparation method of a cyanoethoxyalkane derivative according to the present invention will be further described in detail below through specific examples.

[0022] Example 1: Add 360 g of galactose and 1080 g of deionized water into a three-necked jacketed kettle equipped with a thermometer and a stirrer, stir evenly, after heating to 50 °C, add 119 g of potassium borohydride in batches, after cooling to room temperature, add 0.8 g of sodium hydroxide, heat to 30 °C, dropwise add 954 g of acrylonitrile, keep the temperature at 30 °C and react for 24 h, stop the reaction, and cool to room temperature.

[0023] After the reaction is completed, the reaction solution is extracted with 720 g of ether, then 720 g of n-hexane is added dropwise to the organic layer, stirred and crystallized for 2 h, then filtered by suction, and the filter cake is dried in vacuo to obtain 902 g of 1,2,3,4,5,6-hexa(2-cyanooxy)hexane. The purity is detected by LC (liquid chromatography) to be 99.37%, and the molar yield is calculated to be 90.11%.

[0024] Example 2: Add 180 g of sorbose and 1800 g of deionized water into a three-necked jacketed kettle equipped with a thermometer and a stirrer, stir evenly, after heating to 70 °C, add 81 g of potassium borohydride in batches, after cooling to room temperature, add 5.6 g of potassium hydroxide, heat to 45 °C, dropwise add 382 g of acrylonitrile, keep the temperature at 45 °C and react for 24 h, stop the reaction, and cool to room temperature.

[0025] After the reaction is completed, the reaction solution is extracted with 900 g of methyl tert-butyl ether, then 3600 g of toluene is added dropwise to the organic layer, stirred and crystallized for 2 h, then filtered by suction, and the filter cake is dried in vacuo to obtain 459 g of 1,2,3,4,5,6-hexa(2-cyanooxy)hexane. The purity is detected by LC (liquid chromatography) to be 99.29%, and the molar yield is calculated to be 91.70%.

[0026] Example 3: Add 150 g of xylose and 900 g of deionized water into a three-necked jacketed kettle equipped with a thermometer and a stirrer, stir evenly, after heating to 60 °C, add 49 g of sodium borohydride in batches, after cooling to room temperature, add 2.8 g of potassium hydroxide, heat to 40 °C, dropwise add 424 g of acrylonitrile, keep the temperature at 40 °C and react for 24 h, stop the reaction, and cool to room temperature.

[0027] After the reaction was completed, the reaction solution was extracted with 450 g of dimethyl carbonate, and then 900 g of cyclohexane was added dropwise to the organic layer. After stirring and crystallizing for 2 h, filtration was carried out by suction, and the filter cake was dried under vacuum to obtain 406 g of 1,2,3,4,5-penta(2-cyanooxy)pentane. The purity was detected by LC (liquid chromatography) to be 99.83%, and the molar yield was calculated to be 97.25%. The proton nuclear magnetic resonance spectrum of the product is as Figure 1 shown, 1 H NMR(400MHz, CDCl 3 )δ3.92-3.82(4H, m), 3.78-3.64 (12H, m), 3.62(1H, t, J = 4 Hz),2.66 (10H, q, J = 4.0Hz). The carbon nuclear magnetic resonance spectrum of the product is as Figure 2 shown, 13 C NMR(100MHz, CDCl 3 )δ120.02,119.86, 119.73, 80.20, 79.74, 71.11, 68.45, 66.87, 66.68, 19.81, 19.75,19.34.

[0028] Example 4: 300 g of xylose and 1500 g of deionized water were added to a three-necked jacketed kettle equipped with a thermometer and a stirrer, and stirred evenly. After heating to 60 °C, 130 g of potassium borohydride was added in batches. After cooling to room temperature, 4 g of sodium hydroxide was added, and the temperature was raised to 40 °C. 742 g of acrylonitrile was added dropwise, and the reaction was carried out at 40 °C for 24 h. The reaction was stopped and cooled to room temperature.

[0029] After the reaction was completed, the reaction solution was extracted with 900 g of dimethyl carbonate, and then 1800 g of cyclohexane was added dropwise to the organic layer. After stirring and crystallizing for 2 h, filtration was carried out by suction, and the filter cake was dried under vacuum to obtain 795 g of 1,2,3,4,5-penta(2-cyanooxy)pentane. The purity was detected by LC (liquid chromatography) to be 99.83%, and the molar yield was calculated to be 95.21%.

[0030] Example 5: 300 g of lyxose and 1200 g of deionized water were added to a three-necked jacketed kettle equipped with a thermometer and a stirrer, and stirred evenly. After heating to 55 °C, 188.5 g of sodium cyanoborohydride was added in batches. After cooling to room temperature, 1.48 g of calcium hydroxide was added, and the temperature was raised to 38 °C. 636 g of acrylonitrile was added dropwise, and the reaction was carried out at 38 °C for 24 h. The reaction was stopped and cooled to room temperature.

[0031] After the reaction was completed, the reaction solution was extracted with 750 g of ethyl acetate. Then, 1500 g of carbon tetrachloride was added dropwise to the organic layer. After stirring and crystallizing for 2 h, filtration was carried out by suction, and the filter cake was dried in vacuo to obtain 746 g of 1,2,3,4,5-penta(2-cyanooxy)pentane. The purity was detected by LC (liquid chromatography) to be 99.91%, and the molar yield was calculated to be 89.34%.

[0032] Example 6: 240 g of erythrose and 960 g of deionized water were added to a three-necked jacketed kettle equipped with a thermometer and a stirrer, and stirred evenly. After heating to 65 °C, 91 g of sodium borohydride was added in batches. After cooling to room temperature, 8 g of sodium hydroxide was added, and the temperature was raised to 40 °C. 848 g of acrylonitrile was added dropwise, and the reaction was carried out at 40 °C for 24 h. The reaction was stopped and cooled to room temperature.

[0033] After the reaction was completed, the reaction solution was first extracted with 720 g of dichloromethane. Then, 1440 g of n-hexane was added dropwise to the organic layer. After stirring and crystallizing for 2 h, filtration was carried out by suction, and the filter cake was dried in vacuo to obtain 625 g of 1,2,3,4-tetra(2-cyanooxy)butane. The purity was detected by LC (liquid chromatography) to be 99.69%, and the molar yield was calculated to be 93.46%.

[0034] Example 7: 300 g of arabinose and 1500 g of deionized water were added to a three-necked jacketed kettle equipped with a thermometer and a stirrer, and stirred evenly. After heating to 58 °C, 140 g of potassium borohydride was added in batches. After cooling to room temperature, 5.6 g of potassium hydroxide was added, and the temperature was raised to 35 °C. 690 g of acrylonitrile was added dropwise, and the reaction was carried out at 35 °C for 24 h. The reaction was stopped and cooled to room temperature.

[0035] After the reaction was completed, the reaction solution was extracted with 900 g of dimethyl carbonate. Then, 2700 g of toluene was added dropwise to the organic layer. After stirring and crystallizing for 2 h, filtration was carried out by suction, and the filter cake was dried in vacuo to obtain 783 g of 1,2,3,4,5-penta(2-cyanooxy)pentane. The purity was detected by LC (liquid chromatography) to be 99.57%, and the molar yield was calculated to be 93.78%.

[0036] Example 8: 360 g of mannose and 2160 g of deionized water were added to a three-necked jacketed kettle equipped with a thermometer and a stirrer, and stirred evenly. After heating to 60 °C, 98 g of sodium borohydride was added in batches. After cooling to room temperature, 10 g of potassium hydroxide was added, and the temperature was raised to 40 °C. 795 g of acrylonitrile was added dropwise, and the reaction was carried out at 40 °C for 24 h. The reaction was stopped and cooled to room temperature.

[0037] After the reaction was completed, the reaction solution was first extracted with 1800 g of ethyl acetate, and then 2500 g of cyclohexane was added dropwise to the organic layer. After stirring and crystallizing for 2 h, filtration was carried out by suction, and the filter cake was dried in vacuo to obtain 936 g of 1,2,3,4,5,6-hexakis(2-cyanooxy)hexane. The purity was detected by LC (liquid chromatography) to be 99.72%, and the molar yield was calculated to be 93.50%.

[0038] As can be seen from Examples 1 to 8: The sugar was gently reduced to sugar alcohol in water by a boron-based reducing agent; the nucleophilicity of the hydroxyl group of the polyhydric alcohol was enhanced by adding a catalytic amount of inorganic base, thereby promoting the forward progress of the acrylonitrile addition reaction and effectively avoiding the generation of side reactions. Especially under the conditions that xylose was used as the polysaccharide and sodium borohydride or potassium borohydride was used as the reducing agent, the reaction effect was more ideal.

[0039] Comparative Example 9: 200 g of sorbitol and 564 g of acrylonitrile were added to a three-necked jacketed kettle equipped with a thermometer and a stirrer, and stirred evenly. After cooling to 0 °C, 25 g of a 25% aqueous solution of tetramethylammonium hydroxide was added dropwise, and then the temperature was raised to 25 °C and reacted for 48 h. Then, 25 g of a 25% aqueous solution of tetramethylammonium hydroxide was added, and the reaction was continued at 25 °C for 24 h, and then the reaction was stopped.

[0040] After the reaction was completed, 1 L of ether and 1 L of dichloromethane were added to the reaction solution, and after stirring evenly, filtration was carried out through silica gel. The filtrate was concentrated under reduced pressure to obtain 403 g of 1,2,3,4,5,6-hexakis(2-cyanooxy)hexane. The purity was detected by LC (liquid chromatography) to be only 68.05%, and the molar yield was calculated to be 73.19%.

[0041] The experimental results of Comparative Example 9 show that the direct preparation of cyanoethoxyalkane derivatives using polyhydric alcohol as the raw material has the disadvantages of low yield, many by-products, and low product purity.

[0042] From the above examples, it can be obtained that: for the preparation method of the cyanoethoxyalkane derivative of the present invention, the boron-based reducing agent can gently reduce the sugar to sugar alcohol in water; the nucleophilicity of the hydroxyl group of the polyhydric alcohol is enhanced by adding a catalytic amount of inorganic base, thereby promoting the forward progress of the acrylonitrile addition reaction. The whole preparation method has few side reactions, simple post-treatment, high product yield and high purity, meets the purity requirements of the additive for lithium ion battery electrolyte, and is suitable for industrial production.

Claims

1. A method for preparing a cyanoethoxyalkane derivative, comprising the following steps:

1. After mixing polysaccharides and deionized water, the temperature is raised to 50°C-70°C, and a boron reducing agent is added in batches. After cooling to room temperature, a catalytic amount of inorganic base is added to the reaction solution, and the molar ratio of polysaccharides to inorganic base is 1:0.01-1:0.

1. After stirring and dissolving, acrylonitrile is added dropwise at 30°C-45°C. After the addition is completed, the temperature is kept for reaction, and the molar ratio of polysaccharides to acrylonitrile is 1:5-1:9; the boron reducing agent is selected from one of sodium borohydride, potassium borohydride, and sodium cyanoborohydride; 2. After the reaction is completed, a benign organic solvent is first added to the reaction solution for extraction, and then an inert organic solvent is added to the organic phase and stirred for crystallization, and the precipitated solid is vacuum dried to obtain the product.

2. The method for preparing a cyanoethoxyalkane derivative according to claim 1, characterized in that: The polysaccharide is selected from one of erythrose, arabinose, xylose, lyxose, mannose, sorbose and galactose; the mass ratio of the polysaccharide to deionized water is 1:3-1:

10.

3. The method for preparing a cyanoethoxyalkane derivative according to claim 2, characterized in that: The polysaccharide is xylose; the molar ratio of xylose to acrylonitrile is 1:6-8.

4. The method for preparing a cyanoethoxyalkane derivative according to claim 1, characterized in that: The molar ratio of the polysaccharide to the boron reducing agent is 1:1.1~1:1.

5.

5. The method for preparing a cyanoethoxyalkane derivative according to claim 1 or 4, characterized in that: The boron reducing agent is selected from sodium borohydride or potassium borohydride.

6. The method for preparing a cyanoethoxyalkane derivative according to claim 1, characterized in that: The inorganic base is selected from one of sodium hydroxide, potassium hydroxide, lithium hydroxide and calcium hydroxide.

7. The method for preparing a cyanoethoxyalkane derivative according to claim 1, characterized in that: The benign organic solvent is selected from one of ether, methyl tert-butyl ether, ethyl acetate, dimethyl carbonate and dichloromethane, and the inert organic solvent is selected from one of n-hexane, cyclohexane, toluene and carbon tetrachloride.

8. The method for preparing a cyanoethoxyalkane derivative according to claim 1, characterized in that: The mass ratio of the benign organic solvent to the polysaccharide is 1:2-1:5, and the mass ratio of the benign organic solvent to the inert organic solvent is 1:1-1:

4.

9. The method for preparing a cyanoethoxyalkane derivative according to claim 7 or 8, characterized in that: The benign organic solvent is dimethyl carbonate, and the inert organic solvent is cyclohexane.

10. The method for preparing a cyanoethoxyalkane derivative according to claim 7 or 8, characterized in that: The inert organic solvent is added in a dropwise manner, and the mass ratio of the benign organic solvent to the inert organic solvent is 1:2.

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