1, 2, 3, 4, 5-penta (2-cyanoethoxy) pentane crystal and preparation method thereof

Abstract

The invention relates to a 1, 2, 3, 4, 5-penta (2-cyanoethoxy) pentane crystal and a preparation method thereof, the crystal comprises the following unit cell parameters: # imgabs 0 # alpha = 90 degrees, beta = 103.022 + / -0.008 degrees and gamma = 90 degrees, the # imgabs 1 # preparation method comprises the following steps: 1) reacting xylitol and acrylonitrile in the presence of a base catalyst, adding a solvent and water after the reaction is finished, neutralizing with acid, separating out an organic layer, washing with water until the organic layer is neutral, and drying to obtain a 1, 2, 3, 4, 5-penta (2-cyanoethoxy) pentane crystal; concentrating an organic layer to obtain an oily crude product; 2) adding the oily crude product into a first organic solvent, pulping until the oily crude product is solidified, and filtering to obtain a solid crude product; and (3) heating and dissolving the solid crude product obtained in the step (2) by using a second organic solvent, filtering to obtain filtrate, cooling the filtrate to crystallize, and filtering and drying after the crystal is separated out. Impurities and intermediates are eluted with an organic solvent, the purity of the crude product is improved, and the impurities in the crude product can be further dissolved through crystallization purification, so that the purity of the product is improved, and a high-purity product is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation and purification of cyanoethyl ether additives. Specifically, the present application relates to a 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystal and a preparation method thereof. Background Art

[0002] Cyanoethyl ether additives are increasingly being used as electrolyte additives in lithium-ion batteries due to their wide electrochemical window, high anode stability, and high boiling point. With increasing research on 1,2,3,4,5-penta(2-cyanoethoxy)pentane, which has shown promising improvements in electrolyte performance, market demand is emerging.

[0003] There have been many public reports on the preparation methods of cyanoethyl ether additives. US20090111965A1, US20130035272A1, etc. all mention that a series of cyanoethyl ether products can be prepared by functionalizing polyols. However, 1,2,3,4,5-penta(2-cyanoethoxy)pentane generally appears as an intermediate, or its synthesis process is simply described without involving the separation and purification process, nor is its application value as an electrolyte additive studied.

[0004] There is no high-purity 1,2,3,4,5-five (2-cyanoethoxy) pentane crystals to sell in the market yet. Small-scale products are mostly purified by column chromatography. It is not high that this method obtains product purity, and it is still liquid, and intermediate, by-product and product are mutually soluble, and it is impossible to separate product and intermediate by means such as distillation extraction. At present, the equipment demand for preparing this compound is high, and refining cost is high, and quality and output are low, and it is impossible to meet market demand. Crystallization is a method that is easy to think of, but the intermediate and by-product obtained in the mode of polyol functionalization have a solubility effect on the product, making crystallization difficult, and the influence of factors such as recrystallization solvent type, usage amount and crystallization temperature, the selection of crystallization path is difficult to determine. Summary of the Invention

[0005] The present invention addresses numerous problems existing in the prior art and provides a 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystal and a preparation method thereof. The crude 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystal is subjected to solvent purification and crystallization to improve product purity and obtain a crystalline form. The method is easy to operate, has high industrial feasibility, uses readily available solvents, and is low in cost.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] The present invention provides a 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystal, the structural formula of the crystal is shown in Formula I:

[0008]

[0009] The crystal includes the following unit cell parameters α=90°, β=103.022±0.008°, γ=90°,

[0010] The crystal space group is P21 / n, and the crystal system belongs to the monoclinic system.

[0011] The melting point of the crystals is 55.88-57.14°C.

[0012] The present invention also provides a method for preparing 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals, which comprises the following steps:

[0013] 1) reacting xylitol and acrylonitrile in the presence of an alkali catalyst, adding a solvent after the reaction is complete, neutralizing with an acid, separating the organic layer, washing with water until neutral, and concentrating the organic layer to obtain an oily crude product;

[0014] 2) adding the first organic solvent to the crude oil product and beating the crude oil product until the crude oil product solidifies, and filtering to obtain a solid crude product;

[0015] 3) The crude solid product obtained in step 2) is dissolved by heating with a second organic solvent, filtered to obtain a filtrate, and the filtrate is cooled until crystallization occurs. After the crystals precipitate, they are filtered and dried to obtain the product.

[0016] The present invention also provides the use of the aforementioned 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals and / or the 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals prepared by the aforementioned preparation method in lithium-ion batteries. The 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals can be used as a lithium-ion electrolyte additive.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The preparation method of 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals provided by the present invention uses a solvent to elute impurities and intermediates to improve the purity of a crude product. Crystallization purification can further dissolve impurities in the crude product, thereby improving the purity of the product and obtaining a high-purity product.

[0019] The purification process of the present invention reduces impurities in the crude product by beating, changing its properties, thereby enabling crystallization of the crude product. Crystallization is a purification method that is easily implemented in industrial production, making this process potentially industrializable. It provides a feasible solution for large-scale production of high-purity products. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a diagram of the single crystal structure of the crystal obtained in Example 1.

[0021] Figure 2 This is the XRD pattern of the crystalline powder obtained in Example 1. DETAILED DESCRIPTION

[0022] The following detailed description specifically discloses an embodiment of the present application's 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals and their preparation methods. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially identical structures may be omitted. This is to avoid unnecessary length in the following description and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0023] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0024] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0025] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0026] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0027] 【1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals】

[0028] The present invention provides 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals, the structural formula of which is shown in Formula I:

[0029]

[0030] The crystal includes the following unit cell parameters α=90°, β=103.022±0.008°, γ=90°,

[0031] The crystal space group is P21 / n, and the crystal system belongs to the monoclinic system.

[0032] The melting point of the crystals is 55.88-57.14°C.

[0033] Preparation method of 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals

[0034]

[0035] The present invention also provides a method for preparing 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals, the method comprising the following steps:

[0036] 1) reacting xylitol and acrylonitrile in the presence of an alkali catalyst, adding a solvent after the reaction is complete, neutralizing with an acid, separating the organic layer, washing with water until neutral, and concentrating the organic layer to obtain an oily crude product;

[0037] 2) adding the first organic solvent to the crude oil product and beating the crude oil product until the crude oil product solidifies, and filtering to obtain a solid crude product;

[0038] 3) The crude solid product obtained in step 2) is dissolved by heating with a second organic solvent, filtered to obtain a filtrate, and the filtrate is cooled until crystallization occurs. After the crystals precipitate, they are filtered and dried to obtain the product.

[0039] In the preparation method of 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals provided by the present invention, in step 1), xylitol and acrylonitrile are reacted in the presence of an alkali catalyst, a solvent is added after the reaction is completed, the reaction is neutralized with an acid, an organic layer is separated, the organic layer is washed with water until neutral, and the organic layer is concentrated to obtain an oily crude product of 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals.

[0040] In step 1) of the present invention, the base catalyst is selected from one or more of alkali metal hydroxides, alkaline earth metal hydroxides, ammonium hydroxide, and derivatives thereof. Examples of alkali metal hydroxides include one or more of sodium hydroxide and potassium hydroxide. Examples of ammonium hydroxide and derivatives thereof include one or more of dimethyldiethylammonium hydroxide, tetrabutylammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, trimethylbenzylammonium hydroxide, and triethylbenzylammonium hydroxide.

[0041] In step 1) of the present invention, the molar ratio of xylitol, acrylonitrile, and base catalyst is 1.0:(5.0-8.0):(0.1-2.0). Optionally, the molar ratio may be 1.0:(5.0-5.5):(0.1-2.0), 1.0:(5.5-8.0):(0.1-2.0), 1.0:(5.0-8.0):(0.1-0.5), 1.0:(5.0-8.0):(0.5-2.0), etc.

[0042] In step 1) of the present invention, the reaction temperature is 40°C to 80°C, and can be 40°C to 45°C, 45°C to 60°C, or 60°C to 80°C.

[0043] In step 1) of the present invention, the reaction time is 2 h to 24 h, and can be 2 h to 8 h, 8 h to 12 h, 12 h to 16 h, or 16 h to 24 h.

[0044] In step 1) of the present invention, the solvent is an organic solvent and water, and the organic solvent is one or more of dichloromethane, dichloroethane, cyclohexane, and carbonate solvents.

[0045] In step 1) of the present invention, the acid is selected from an inorganic acid or an organic acid. The inorganic acid is selected from one or more of hydrochloric acid, sulfuric acid, and phosphoric acid. The organic acid is selected from one or more of formic acid and acetic acid.

[0046] In a specific embodiment, sodium hydroxide and triethylbenzyl ammonium hydroxide are added to a reaction flask and dissolved in water. Xylitol is then added, stirred, and heated. Acrylonitrile is added dropwise, and the mixture is stirred after completion. The reaction endpoint is determined by central control. Upon completion of the reaction, dichloromethane and water are added, and the mixture is neutralized with hydrochloric acid. The organic layer is separated and washed with water until neutral. The organic layer is concentrated to obtain a crude product, which is a light yellow to yellow viscous liquid.

[0047] In the method for preparing 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals provided by the present invention, step 2) is to add a first organic solvent to the crude oily product of 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals and slurry the crude oily product until the crude oily product solidifies, and then filter to obtain a solid crude product. Specifically:

[0048] In step 2) of the present invention, the first organic solvent is selected from one or more of an alcohol solvent, an ether solvent, and a carbonate solvent. Preferably, the first organic solvent is an alcohol solvent, as alcohol solvents have the best pulping effect.

[0049] Optionally, the alcohol solvent is selected from one or more of isopropanol, ethanol, methanol, and n-butanol.

[0050] Optionally, the ether solvent is selected from one or more of 1,4-dioxane and ethylene glycol dimethyl ether.

[0051] Optionally, the carbonate solvent is selected from one or more of diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, fluoroethylene carbonate, dipropyl carbonate, methylpropyl carbonate, and dibutyl carbonate.

[0052] In step 2) of the present invention, the oily crude product of 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals is repeatedly added to the first organic solvent for beating until the oily crude product solidifies. Specifically: the oily crude product is added to the first organic solvent for beating, and the crude product will gradually become viscous during the beating process. If the crude product fails to solidify into a solid, the first organic solvent can be separated, the crude product is retained, and a new first organic solvent is added again for beating until a solid crude product is obtained. Among them, the first organic solvent is used to effectively separate impurities in the crude product, and the impurities include impurities generated by side reactions such as cyano hydrolysis and polymerization, and intermediates remaining from incomplete reactions.

[0053] In step 2) of the present invention, the mass volume ratio of the crude oily product to the first organic solvent may be 1 g: (2-20) mL, but is not limited to 1 g: (2-20) mL. Alternatively, the mass volume ratio of the crude oily product of the 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals to the first organic solvent may be, for example, 1 g: (2-5) mL, 1 g: (5-8) mL, or 1 g: (8-20) mL. Preferably, the mass volume ratio of the crude oily product of the 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals to the first organic solvent is 1 g: (5-8) mL.

[0054] In step 2) of the present invention, the beating temperature is -20 to 60° C. Alternatively, the beating temperature may be -20 to 20° C., 20 to 30° C., 30 to 60° C., 0 to 10° C., 10 to 20° C., or 15 to 25° C. Preferably, the beating temperature may be 20 to 30° C.

[0055] In step 2) of the present invention, the beating time is 6 to 20 hours. Optionally, the beating time is 6 to 8 hours, 8 to 12 hours, 12 to 16 hours, or 16 to 20 hours.

[0056] In the method for preparing 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals provided by the present invention, step 3) is to heat and dissolve the crude solid product obtained in step 2) in a second organic solvent, perform hot filtration after dissolution to remove mechanical impurities, cool the filtrate until crystallization occurs, filter the precipitated crystals, and dry them to obtain the product. Specifically:

[0057] In step 3) of the present invention, the second organic solvent is selected from one or more of an alcohol solvent, an ether solvent, and a carbonate solvent. Preferably, the second organic solvent is a carbonate solvent, and a crystallization solvent carbonate solvent has the best effect.

[0058] Optionally, the alcohol solvent is selected from one or more of isopropanol, ethanol, methanol, and n-butanol.

[0059] Optionally, the ether solvent is selected from one or more of 1,4-dioxane and ethylene glycol dimethyl ether.

[0060] Optionally, the carbonate solvent is selected from one or more of diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, fluoroethylene carbonate, dipropyl carbonate, methylpropyl carbonate, and dibutyl carbonate.

[0061] In step 3) of the present invention, the mass volume ratio of the crude oil to the second organic solvent is 1 g: (2-5) mL. Alternatively, the mass volume ratio of the crude oil to the second organic solvent can be, for example, 1 g: (2-4) mL or 1 g: (4-5) mL.

[0062] In step 3) of the present invention, the dissolution temperature is 30-80° C. Alternatively, the dissolution temperature may be, for example, 30-40° C., 40-60° C., 40-50° C., 50-60° C., 60-70° C., 70-80° C., 60-80° C., etc. Preferably, the dissolution temperature is 40-60° C.

[0063] In step 3) of the present invention, the crystallization temperature is -20 to 60°C. Alternatively, the crystallization temperature can be, for example, -20 to 20°C, 20 to 30°C, 20 to 25°C, 25 to 30°C, or 30 to 60°C. Preferably, the crystallization temperature is 20 to 30°C. Crystallization purification can further dissolve impurities in the crude product, thereby improving product purity.

[0064] In step 3) of the present invention, the drying temperature is 0-80°C. Alternatively, the drying temperature may be, for example, 0-30°C, 30-50°C, 30-40°C, 40-50°C, 50-60°C, 60-80°C, etc. Preferably, the drying temperature is 30-50°C. Drying may be, for example, vacuum drying.

[0065]

application

[0066] The present invention also provides the use of the aforementioned 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals and / or the 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals prepared by the aforementioned preparation method in lithium-ion batteries. The 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals can be used as a lithium-ion electrolyte additive.

[0067] The technical solution of the present application is described clearly and completely below in conjunction with the embodiments of the present invention. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by professionals in this field based on the above-mentioned contents of the present invention still fall within the scope of protection of the present invention.

[0068] In the following examples, all reagents, materials and instruments used are commercially available unless otherwise specified.

[0069] Crystal powder XRD tester: instrument model: Bruker D8.

[0070] Single crystal structure tester: PANalytical (brand: ICA) from the Netherlands.

[0071] Melting point tester: Video melting point apparatus (Shanghai Jiahang Instrument Co., Ltd., model: Digipol-M50).

[0072] Example 1

[0073] 1) Crude product synthesis

[0074] 6.6g of sodium hydroxide (0.016mol 0.5eq) and 0.66g of triethylbenzylammonium hydroxide (40% aqueous solution) were added to a reaction flask, 24g of water was added to dissolve, and 50g of xylitol (0.33mol 1.0eq) was added and stirred to dissolve. 96g of acrylonitrile (1.79mol 5.5eq) was added dropwise at approximately 45°C, and the mixture was stirred and reacted for 12-16 hours. The reaction endpoint was monitored by TLC. After the reaction was complete, 150g of dichloromethane was added, followed by 100g of water and 17g of hydrochloric acid for neutralization. After separation, the organic layer was washed with water 2-3 times until the aqueous phase was neutral. The organic layer was concentrated to obtain 140g of a crude oily product, which was a light yellow to yellow viscous liquid.

[0075] 2) Product refining

[0076] 140g of the crude oil was added to 700mL of 1.4-dioxane and beaten at a beating temperature of 10-20°C. The mixture was stirred for 6-8 hours, the beating solvent was separated, 700mL of 1.4-dioxane was added again and stirred until the crude product solidified. The mixture was filtered and the filter cake was added with 300mL of ethanol and stirred. The mixture was heated to 60-70°C to dissolve the mixture. After dissolution, the mixture was hot filtered to remove mechanical impurities. The filtrate was cooled to 20-25°C for crystallization. The crystals were filtered after precipitation. The product was vacuum dried at 30-40°C to obtain 86g of 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals with a yield of 62.3% and a purity of 99.72%. 1 H NMR(400MHz,dmso)δ3.84,3.83,3.82,3.80,3.79,3.77,3.76,3.69,3.68,3.67,3.66,3 .65,3.64,3.63,3.61,3.60,3.59,3.58,3.55,3.54,3.53,2.78,2.77,2.76,2.74,2.73.

[0077] Among them, the single crystal structure is shown in the figure Figure 1 As shown. Unit cell parameters α=90°, β=103.022±0.008°, γ=90°, The crystal space group is P21 / n, and the crystal system belongs to monoclinic system. Figure 2 shown.

[0078] Example 2

[0079] 1) Crude product synthesis: refer to Example 1

[0080] 2) Product refining

[0081] 140g of the crude oil was added to 1000mL of diethyl carbonate and beaten at a beating temperature of 15-25°C. The mixture was stirred for 16-20 hours, the beating solvent was separated, and 1000mL of diethyl carbonate was added again with stirring. This operation was repeated 3-4 times. The crude product solidified, filtered, and the filter cake was added with 400mL of diethyl carbonate and stirred. The mixture was heated to 70-80°C to dissolve. After dissolution, the mixture was hot filtered to remove mechanical impurities. The filtrate was cooled to 20-30°C and crystallized. After the crystals separated out, they were filtered. The product was vacuum dried at 30-40°C with a yield of 66.7%, to obtain 92g of 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals with a purity of 99.58%.

[0082] Example 3

[0083] 1) Crude product synthesis: refer to Example 1

[0084] 2) Product refining

[0085] 140g of the crude oil was added to 800mL of isopropanol and slurried at a slurry temperature of 0-10°C. The mixture was stirred for 8-12 hours, the slurry solvent was separated, the crude product solidified, filtered, and the filter cake was added with 300mL of ethanol and stirred. The mixture was heated to 60-70°C to dissolve the product. After dissolution, the mixture was hot filtered to remove mechanical impurities. The filtrate was cooled to 20-25°C for crystallization. The crystals precipitated and were filtered. The product was vacuum dried at 30-40°C to obtain 102g of 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals with a yield of 74% and a purity of 99.56%.

[0086] Example 4

[0087] 1) Crude product synthesis: refer to Example 1

[0088] 2) Product refining

[0089] 140g of the crude oil was added to 800mL of isopropanol and slurried at a slurry temperature of 0-10°C. The mixture was stirred for 8-12 hours, the slurry solvent was separated, the crude product solidified, filtered, and the filter cake was added with 400mL of methanol and stirred. The product was heated to 50-60°C to dissolve. After dissolution, it was hot filtered to remove mechanical impurities. The filtrate was cooled to 20-25°C for crystallization. The crystals precipitated and were filtered. The product was vacuum dried at 30-40°C to obtain 83.7g of 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals, with a yield of 60.6% and a purity of 99.93%.

[0090] The applicant declares that while the present invention uses the above-described embodiments to illustrate the 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals and their preparation methods, the present invention is not limited to these embodiments, nor does it necessarily rely on these embodiments for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for raw materials in the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

[0091] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0092] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystal, characterized in that: The structural formula of the crystal is shown in Formula I: The crystal includes the following unit cell parameters α=90°, β=103.022±0.008°, γ=90°, 2. The 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystal according to claim 1, characterized in that The crystal space group is P21 / n, and the crystal system belongs to the monoclinic system.

3. The 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystal according to claim 1, characterized in that The crystal melting point is 55.88-57.14°C.

4. A method for preparing 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals, characterized in that: The preparation method comprises: 1) reacting xylitol and acrylonitrile in the presence of an alkali catalyst, adding a solvent after the reaction is complete, neutralizing with an acid, separating the organic layer, washing with water until neutral, and concentrating the organic layer to obtain an oily crude product; 2) adding the first organic solvent to the crude oil product and beating the crude oil product until the crude oil product solidifies, and filtering to obtain a solid crude product; 3) The crude solid product obtained in step 2) is dissolved by heating with a second organic solvent, filtered to obtain a filtrate, and the filtrate is cooled until crystallization occurs. After the crystals precipitate, they are filtered and dried to obtain the product.

5. The method for preparing 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals according to claim 4, wherein: Also includes any one or more of the following features: A1) in step 1), the base catalyst is selected from one or more of alkali metal hydroxides, alkaline earth metal hydroxides, ammonium hydroxide and derivatives thereof; A2) In step 1), the molar ratio of xylitol, acrylonitrile, and base catalyst is 1.0:(5.0-8.0):(0.1-2.0); A3) In step 1), the reaction temperature is 40°C to 80°C; A4) In step 1), the reaction time is 2 h to 24 h; A5) in step 1), the solvent is selected from an organic solvent and water, and the organic solvent is one or more of dichloromethane, dichloroethane, cyclohexane, and carbonate solvents; A6) In step 1), the acid is selected from an inorganic acid or an organic acid.

6. The method for preparing 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals according to claim 5, characterized in that: Also includes any one or more of the following features: A11) In step 1), the alkali metal hydroxide is selected from one or more of sodium hydroxide and potassium hydroxide; A12) in step 1), the ammonium hydroxide and its derivatives are selected from one or more of ammonium hydroxide, dimethyldiethylammonium hydroxide, tetrabutylammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, trimethylbenzylammonium hydroxide, and triethylbenzylammonium hydroxide; A61) In step 1), the inorganic acid is selected from one or more of hydrochloric acid, sulfuric acid, and phosphoric acid; A62) In step 1), the organic acid is selected from one or more of formic acid and acetic acid.

7. The method for preparing 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals according to claim 4, characterized in that: Also includes any one or more of the following features: B1) in step 2), the first organic solvent is selected from one or more of an alcohol solvent, an ether solvent, and a carbonate solvent; B2) in step 2), the crude oily product is repeatedly added to the first organic solvent for slurrying until the crude oily product solidifies; B3) In step 2), the mass volume ratio of the crude oil to the first organic solvent is 1 g: (2-20) mL.

8. The method for preparing 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals according to claim 7, characterized in that: Also includes any one or more of the following features: B11) in step 2), the alcohol solvent is selected from one or more of isopropanol, ethanol, methanol, and n-butanol; B12) in step 2), the ether solvent is selected from one or more of 1,4-dioxane and ethylene glycol dimethyl ether; B13) in step 2), the carbonate solvent is selected from one or more of diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, fluoroethylene carbonate, dipropyl carbonate, methylpropyl carbonate, and dibutyl carbonate; B14) in step 2), the first organic solvent is an alcohol solvent; B21) In step 2), the beating temperature is -20 to 60°C; B22) In step 2), the beating time is 6 to 20 hours; B31) In step 2), the mass volume ratio of the crude oil to the first organic solvent is 1 g: (5-8) mL.

9. The method for preparing 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals according to claim 8, characterized in that: In feature B21), the beating temperature is 20 to 30°C.

10. The method for preparing 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals according to claim 4, characterized in that: Also includes any one or more of the following features: C1) in step 3), the second organic solvent is selected from one or more of an alcohol solvent, an ether solvent, and a carbonate solvent; C2) in step 3), the dissolution temperature is 30 to 80°C; C3) in step 3), the crystallization temperature is -20 to 60°C; C4) in step 3), the drying temperature is 0 to 80°C; C5) The mass volume ratio of the crude oil to the second organic solvent is 1 g: (2-5) mL.

11. The method for preparing 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals according to claim 10, characterized in that: Also includes any one or more of the following features: C11) in step 3), the alcohol solvent is selected from one or more of isopropanol, ethanol, methanol, and n-butanol; C12) in step 3), the ether solvent is selected from one or more of 1,4-dioxane and ethylene glycol dimethyl ether; C13) in step 3), the carbonate solvent is selected from one or more of diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, fluoroethylene carbonate, dipropyl carbonate, methylpropyl carbonate, and dibutyl carbonate; C14) in step 3), the second organic solvent is a carbonate solvent; C21) in step 3), the dissolution temperature is 40 to 60°C; C31) in step 3), the crystallization temperature is 20 to 30°C; C41) In step 3), the drying temperature is 30-50°C.

12. Use of the 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals according to any one of claims 1 to 3 and / or the 1,2,3,4,5-penta(2-cyanoethoxy)pentane crystals prepared according to the method according to any one of claims 4 to 11 in lithium-ion batteries.

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