Preparation method of cyclic ethylene carbonate and electrolyte additive

Abstract

The invention relates to the technical field of organic synthesis and new material synthesis, in particular to a preparation method of cyclic ethylene carbonate and an electrolyte additive, and the method comprises the following steps: reacting a compound as shown in a formula (I) in the presence of alkali at a preset temperature to prepare difluorocarbene; the cyclic ethylene carbonate is prepared by reacting difluorocarbene with a compound as shown in a formula (II) in the presence of water and alkali. The preparation method provided by the invention is short in reaction period, low in cost, high in yield, green and environment-friendly.

Description

Technical Field

[0001] This application relates to the fields of organic synthesis and new material synthesis technology, and in particular to a method for preparing cyclic ethylene carbonate and an electrolyte additive. Background Technology

[0002] Carbonate compounds are a class of organic solvents with high boiling points. Due to their good biodegradability, solubility, low toxicity, and low corrosivity, they are widely used in many fields such as material synthesis, plastics, textiles, battery electrolytes, and metal extractants.

[0003] Traditional methods for preparing cyclic carbonate compounds mainly include the phosgene method, transesterification method, epoxy cycloaddition method, and urea method. However, the phosgene method is prone to environmental pollution and poses significant safety hazards; the transesterification method has a long reaction time and low yield; the epoxy cycloaddition method requires a pressure vessel, resulting in high reaction pressure and a long reaction cycle, which also poses certain safety risks; and the urea method uses a large amount of catalyst, leading to high costs, and the catalyst can easily decompose urea to produce ammonia, causing environmental pollution. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for preparing cyclic ethylene carbonate and an electrolyte additive. The preparation method for cyclic ethylene carbonate has a short reaction cycle, low cost, high yield, and is environmentally friendly.

[0005] The first aspect of this application provides a method for preparing cyclic ethylene carbonate, comprising the following steps:

[0006] Difluorocarbene was prepared by reacting the compound shown in formula (I) in the presence of a base and at a predetermined temperature;

[0007] A cyclic ethylene carbonate was prepared by reacting a difluorocarbene with the compound shown in formula (II) in the presence of water and a base; the structural formula of the cyclic ethylene carbonate is shown in formula (V).

[0008] ; ; ;

[0009] Wherein, R is selected from any one of substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, and substituted or unsubstituted aryl;

[0010] R fIt is selected from any one of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, halogen, nitro, substituted or unsubstituted amino, substituted or unsubstituted alkoxy, substituted or unsubstituted imidazolyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted thiophene, and substituted or unsubstituted furanyl.

[0011] In some embodiments, the method for preparing cyclic ethylene carbonate includes the following steps: mixing the compound represented by formula (I) with an alkali, an organic solvent and water, heating to a preset temperature to prepare a solution containing difluorocarbene; adding the compound represented by formula (II) to the solution containing difluorocarbene to react and prepare cyclic ethylene carbonate.

[0012] In some embodiments, the compound represented by formula (II) is added dropwise to a solution containing difluorocarbene.

[0013] In some embodiments, the organic solvent includes one or more of acetonitrile, 1,2-dichloroethane, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, and triethyl phosphate.

[0014] In some embodiments, the base includes one or more of triethylamine, diisopropylethylamine, pyridine, imidazole, piperidine, pyrrole, 1,8-diazabicycloundec-7-ene, 4-dimethylaminopyridine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphide.

[0015] In some implementations, the preset temperature is 50°C to 150°C.

[0016] In some embodiments, the molar ratio of the compound shown in formula (I) to the compound shown in formula (II) is (2~5):1.

[0017] In some embodiments, the molar ratio of the base to the compound represented by formula (II) is (2~5):1.

[0018] In some embodiments, the molar ratio of water to the compound represented by formula (II) is (5~10):1.

[0019] In some embodiments, the reaction process for preparing cyclic ethylene carbonate is carried out under a nitrogen atmosphere.

[0020] The second aspect of this application provides an electrolyte additive comprising cyclic ethylene carbonate prepared according to the preparation method provided in the first aspect of this application.

[0021] Compared with the prior art, this application has the following beneficial effects:

[0022] This application describes a method for preparing difluorocarbene by in-situ generation of the compound of formula (I) in an organic solvent under the action of an alkali. The difluorocarbene and the compound of formula (II) then react in the presence of an alkali and water to generate cyclic ethylene carbonate. This preparation method uses readily available raw materials, operates under mild reaction conditions, involves fewer process steps, improves product yield and purity, is environmentally friendly, and allows for the recycling and reuse of the reaction solvent, thus reducing costs. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart illustrating a method for preparing cyclic ethylene carbonate in some embodiments of this application. Detailed Implementation

[0025] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0026] Therefore, this application is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of this application are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of this application.

[0027] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0028] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0029] In this article, when referring to units of data ranges, if a unit is only followed by the right endpoint, it means that the units of the left and right endpoints are the same.

[0030] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions. Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical solutions.

[0031] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0033] In this application, the term "substituted or unsubstituted" means substituted with one or more substituents selected from the following: deuterium, halogen, cyano, nitro, hydroxyl, mercapto, carbonyl, ester, imide, amino, phosphine, oxo, alkoxy, trifluoromethoxy, aryloxy, alkylthio, arylthio, alkylsulfonyl, arylsulfonyl, silyl, boron, alkyl, cycloalkyl, alkenyl, aryl, aralkyl, arylenyl, alkylaryl, alkylamine, aralkylamine, heteroarylamine, arylamine, arylphosphine and heteroaryl, acenaphthel, or unsubstituted; or substituted with a substituent linking two or more substituents from the examples above, or unsubstituted. For example, "substituent linking two or more substituents" may include biphenyl, i.e., biphenyl may be aryl, or may be a substituent linking two phenyl groups.

[0034] In this application, the term "alkyl" refers to a saturated hydrocarbon containing a primary (normal) carbon atom, or a secondary carbon atom, or a tertiary carbon atom, or a quaternary carbon atom, or a combination thereof. Phrases containing this term, such as "C1-C9 alkyl," refer to alkyl groups containing 1 to 9 carbon atoms, and each occurrence can independently be C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl, or C9 alkyl. Suitable examples include, but are not limited to: methyl (Me, -CH3), ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 2-propyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 2-methyl-1-propyl (i-Bu, i-butyl, -CH2CH(CH3)2), 2-butyl (s-Bu, s-butyl, -CH(CH3)) CH2CH3), 2-methyl-2-propyl (t-Bu, t-butyl, -C(CH3)3), 1-pentyl (n-pentyl, -CH2CH2CH2CH2CH3), 2-pentyl (-CH(CH3)CH2CH2CH3), 3-pentyl (-CH(CH2CH3)2), 2-methyl-2-butyl (-C(CH3)2CH2CH3), 3-methyl-2-butyl (-CH(CH3)CH(CH3)2), 3-methyl-1-butyl (-CH2CH2) CH(CH3)2), 2-methyl-1-butyl (-CH2CH(CH3)CH2CH3), 1-hexyl (-CH2CH2CH2CH2CH2CH3), 2-hexyl (-CH(CH3)CH2CH2CH2CH3), 3-hexyl (-CH(CH2CH3)(CH2CH2CH3)), 2-methyl-2-pentyl (-C(CH3)2CH2CH2CH3), 3-methyl-2-pentyl (-CH(CH3)CH(CH3)CH2CH 3), 4-methyl-2-pentyl (-CH(CH3)CH2CH(CH3)2), 3-methyl-3-pentyl (-C(CH3)(CH2CH3)2), 2-methyl-3-pentyl (-CH(CH2CH3)CH(CH3)2), 2,3-dimethyl-2-butyl (-C(CH3)2CH(CH3)2), 3,3-dimethyl-2-butyl (-CH(CH3)C(CH3)3, octyl (-(CH2)7CH3), cyclopropyl, cyclobutyl and cyclopentyl.

[0035] The term "alkenyl" refers to a compound containing at least one unsaturated site, i.e., a carbon-carbon sp group. 2Hydrocarbons with a double bond consisting of a positive, secondary, tertiary, or cyclic carbon atom. Phrases containing this term, such as "C2-C9 alkenyl," refer to alkenyl groups containing 2 to 9 carbon atoms, which, each time appearing, can independently be C2-alkenyl, C3-alkenyl, C4-alkenyl, C5-alkenyl, C6-alkenyl, C7-alkenyl, C8-alkenyl, or C9-alkenyl. Suitable examples include, but are not limited to: vinyl (-CH=CH2), allyl (-CH2CH=CH2), cyclopentenyl (-C5H7), and 5-hexenyl (-CH2CH2CH2CH2CH=CH2).

[0036] The term "alkynyl" refers to a hydrocarbon containing at least one unsaturated carbon atom, namely a carbon-carbon sp triple bond, consisting of a positive, secondary, tertiary, or cyclic carbon atom. Phrases containing this term, such as "C2-C9 alkenyl," refer to alkynyl groups containing 2 to 9 carbon atoms, and each occurrence can be independently C2-alkynyl, C3-alkynyl, C4-alkynyl, C5-alkynyl, C6-alkynyl, C7-alkynyl, C8-alkynyl, or C9-alkynyl. Suitable examples include, but are not limited to, ethynyl (-C≡CH) and propynyl (-CH2C≡CH).

[0037] The term "aryl" refers to an aromatic hydrocarbon group derived from an aromatic ring compound by removing one hydrogen atom. It can be a monocyclic aryl, a fused-ring aryl, or a polycyclic aryl; for polycyclic compounds, at least one ring must be an aromatic ring system. For example, "C6~C..." 20 "Aryl" refers to an aryl group containing 6 to 20 carbon atoms. Each time it appears, it can independently be a C6 aryl, C6 aryl, C6 aryl, or C6 aryl. 10 Aryl, C 14 Aryl, C 18 Aryl or C 20 Aryl groups. Suitable examples include, but are not limited to: benzene, biphenyl, naphthalene, anthracene, phenanthrene, dinaphthalene, triphenylene and their derivatives.

[0038] The term "halogen" or "halogen group" refers to F, Cl, Br, or I.

[0039] The term "nitro" refers to the group remaining after removing a hydroxyl group from a nitric acid molecule; its chemical formula is -NO2.

[0040] The term "amino" refers to -NH2.

[0041] The term "alkoxy" refers to a group having an -O-alkyl group, i.e., an alkyl group as defined above connected to the parent nucleus via an oxygen atom. Phrases containing this term, such as "C1-C9 alkoxy," refer to alkyl moieties containing 1-9 carbon atoms, and each occurrence can be independently C1 alkoxy, C4 alkoxy, C5 alkoxy, C6 alkoxy, C7 alkoxy, C8 alkoxy, or C9 alkoxy. Suitable examples include, but are not limited to: methoxy (-O-CH3 or -OMe), ethoxy (-O-CH2CH3 or -OEt), and tert-butoxy (-OC(CH3)3 or -OtBu).

[0042] like Figure 1 As shown, the first aspect of this application provides a method for preparing cyclic ethylene carbonate, comprising the following steps:

[0043] S1. The compound shown in formula (I) is reacted in the presence of a base and at a preset temperature to prepare difluorocarbene.

[0044] S2. Reaction of difluorocarbene with the compound shown in formula (II) in the presence of water and alkali to prepare cyclic ethylene carbonate.

[0045] The structural formula of cyclic ethylene carbonate is shown in formula (V).

[0046] ; ; .

[0047] Wherein, R is selected from any one of substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, or substituted or unsubstituted aryl.

[0048] R f It is selected from any one of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, halogen, nitro, substituted or unsubstituted amino, substituted or unsubstituted alkoxy, substituted or unsubstituted imidazolyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted thiophene, and substituted or unsubstituted furanyl.

[0049] Understandably, in the S2 reaction process described above, the compound shown in formula (II) reacts with difluorocarbene in the presence of water to form the compound shown in formula (III). After defluorination, intramolecular cyclization, and secondary defluorination, the compound shown in formula (III) reacts with water in the presence of a base to form the oxoanion compound shown in formula (IV). The oxoanion compound shown in formula (IV) then undergoes a Cannizzaro reaction with difluorocarbene to form cyclic ethylene carbonate.

[0050] The chemical reaction formulas for the entire preparation process are as follows:

[0051] .

[0052] This application describes a method for preparing difluorocarbene by reacting a compound of formula (I) in an organic solvent with an alkali to generate difluorocarbene in situ. The difluorocarbene is then reacted with an epoxy compound of formula (II) in water to generate a compound of formula (III). The compound of formula (III) is then reacted with water and an alkali to generate a compound of formula (IV). Finally, the compound of formula (IV) reacts with the difluorocarbene to generate cyclic ethylene carbonate. This preparation method uses readily available raw materials, operates under mild conditions, involves few steps, improves product yield and purity, is environmentally friendly, and allows for the recycling and reuse of the reaction solvent, thus reducing costs. In the preparation method provided in this application, the reactions in S1 and S2 are carried out continuously, making the process simple and easy to operate.

[0053] In some embodiments, R is selected from substituted or unsubstituted C1-C. 12 Alkyl, substituted or unsubstituted C2-C 12 alkenyl, substituted or unsubstituted C2-C 12 Alkyne, substituted or unsubstituted C6-C 12 Any of the aryl groups.

[0054] Furthermore, R is selected from substituted or unsubstituted C1-C. 10 Alkyl, substituted or unsubstituted C2-C 10 alkenyl, substituted or unsubstituted C2-C 10 Alkyne, substituted or unsubstituted C6-C 12 Any of the aryl groups.

[0055] Further, R is selected from substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted C2-C8 alkynyl, substituted or unsubstituted C6-C 12 Any of the aryl groups.

[0056] Further, R is selected from substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C2-C6 alkenyl, substituted or unsubstituted C2-C6 ynyl, substituted or unsubstituted C6-C 12 Any of the aryl groups.

[0057] Further, R is selected from substituted or unsubstituted C1-C4 alkyl, substituted or unsubstituted C2-C4 alkenyl, substituted or unsubstituted C2-C4 alkynyl, substituted or unsubstituted C6-C 12 Any of the aryl groups.

[0058] In some implementations, R fSelected from hydrogen, substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C2-C 12 alkenyl, substituted or unsubstituted C2-C 12 Alkyne, substituted or unsubstituted C6-C 12 Aryl, halogen, nitro, substituted or unsubstituted amino, substituted or unsubstituted C1-C 12 Any one of alkoxy, substituted or unsubstituted imidazolyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted thiophene, or substituted or unsubstituted furanyl.

[0059] Furthermore, R f Selected from hydrogen, substituted or unsubstituted C1-C 10 Alkyl, substituted or unsubstituted C2-C 10 alkenyl, substituted or unsubstituted C2-C 10 Alkyne, substituted or unsubstituted C6-C 12 Aryl, halogen, nitro, substituted or unsubstituted amino, substituted or unsubstituted C1-C 10 Any one of alkoxy, substituted or unsubstituted imidazolyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted thiophene, or substituted or unsubstituted furanyl.

[0060] Furthermore, R f Selected from hydrogen, substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted C2-C8 alkenyl, substituted or unsubstituted C2-C8 alkynyl, substituted or unsubstituted C6-C 12 Any one of aryl, halogen, nitro, substituted or unsubstituted amino, substituted or unsubstituted C1-C8 alkoxy, substituted or unsubstituted imidazolyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted thiophene, or substituted or unsubstituted furanyl.

[0061] Furthermore, R f Selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C2-C6 alkenyl, substituted or unsubstituted C2-C6 alkynyl, substituted or unsubstituted C6-C 12 Any one of aryl, halogen, nitro, substituted or unsubstituted amino, substituted or unsubstituted C1-C6 alkoxy, substituted or unsubstituted imidazolyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted thiophene, or substituted or unsubstituted furanyl.

[0062] Furthermore, R f Selected from hydrogen, substituted or unsubstituted C1-C4 alkyl, substituted or unsubstituted C2-C4 alkenyl, substituted or unsubstituted C2-C4 alkynyl, substituted or unsubstituted C6-C 12Any one of aryl, halogen, nitro, substituted or unsubstituted amino, substituted or unsubstituted C1-C4 alkoxy, substituted or unsubstituted imidazolyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted thiophene, or substituted or unsubstituted furanyl.

[0063] In some embodiments, the substituents may be selected, for example, from halogens (fluorine, chlorine, bromine or iodine, etc.), trifluoromethyl, hydroxyl, cyano, C1-C3 alkoxy, C1-C3 alkyl, deuterium, amino, mercapto, nitro, carbonyl, ester, oxo, imide, phosphine oxide, trifluoromethoxy, and any combination thereof.

[0064] In some embodiments, the method for preparing cyclic ethylene carbonate includes the following steps:

[0065] S11. Mix the compound shown in formula (I) with a base, an organic solvent and water, and heat to a preset temperature to prepare a solution containing difluorocarbene.

[0066] S12. Add the compound shown in formula (II) to a solution containing difluorocarbene to prepare cyclic ethylene carbonate.

[0067] In some embodiments, the organic solvent includes one or more of acetonitrile, 1,2-dichloroethane, N,N-dimethylformamide (DMF), N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, and triethyl phosphate.

[0068] In some embodiments, the base includes one or more of triethylamine, diisopropylethylamine (DIPEA), pyridine, imidazole, piperidine, pyrrole, 1,8-diazabicycloundec-7-ene (DBU), 4-dimethylaminopyridine (DMAP), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphine (BEMP).

[0069] In some embodiments, the compound represented by formula (II) is added dropwise to a solution containing difluorocarbene.

[0070] In some embodiments, difluorocarbene and the compound represented by formula (II) react at a preset temperature for a preset time.

[0071] In some embodiments, the preset temperature is 50°C to 150°C, including but not limited to 50°C, 70°C, 90°C, 110°C, 130°C, and 150°C. Further, the preset temperature is 80°C to 120°C. Even further, the preset temperature is 100°C to 105°C. Within this preset temperature range, the compound represented by formula (II) exhibits high conversion rate, mild reaction conditions, low energy consumption, and high reaction yield.

[0072] In some embodiments, the preset time is 8h to 20h, including but not limited to 8h, 12h, 16h, and 20h. Further, the preset time is 8h to 15h. Even further, the preset time is 10h to 13h. Within this preset time range, the compound represented by formula (II) has a high conversion rate and a high reaction yield.

[0073] In some embodiments, the molar ratio of the compound represented by formula (I) to the compound represented by formula (II) is (2~5):1. Further, the molar ratio of the compound represented by formula (I) to the compound represented by formula (II) is (2~4):1. Even further, the molar ratio of the compound represented by formula (I) to the compound represented by formula (II) is (3~3.5):1. Within this molar ratio range, the compound represented by formula (II) exhibits high conversion rate, good reaction reproducibility, and high reaction yield.

[0074] In some embodiments, the molar ratio of the base to the compound represented by formula (II) is (2~5):1. Further, the molar ratio of the base to the compound represented by formula (II) is (2~4):1. Even further, the molar ratio of the base to the compound represented by formula (II) is (3~3.5):1. Within this molar ratio range, the compound represented by formula (II) exhibits high conversion, good reaction reproducibility, and high reaction yield.

[0075] In some embodiments, the molar ratio of water to the compound represented by formula (II) is (5~10):1. Further, the molar ratio of water to the compound represented by formula (II) is (6~10):1. Even further, the molar ratio of water to the compound represented by formula (II) is (7~9):1. Within this molar ratio range, the compound represented by formula (II) exhibits high conversion rate, good reaction reproducibility, and high reaction yield.

[0076] In some embodiments, the reaction process for preparing cyclic ethylene carbonate is carried out under an air atmosphere, a nitrogen atmosphere, or an argon atmosphere. Further, the reaction process for preparing cyclic ethylene carbonate is carried out under a nitrogen atmosphere. When the reaction is carried out under a nitrogen atmosphere, the compound represented by formula (II) exhibits high conversion, good reaction selectivity, fewer impurities, and high reaction yield.

[0077] In some embodiments, the method for preparing cyclic ethylene carbonate further includes the following steps:

[0078] S3. Purify the solution containing cyclic ethylene carbonate in S2.

[0079] In some embodiments, the purification process specifically includes the following steps: vacuum distillation of the solution containing cyclic ethylene carbonate in S2.

[0080] In some embodiments, the temperature for vacuum distillation is 20°C to 150°C, including but not limited to 20°C, 50°C, 100°C, and 150°C.

[0081] In some embodiments, the purification process specifically includes the following steps: first, the solution containing cyclic ethylene carbonate in S2 is subjected to atmospheric distillation to remove the solvent from the solution, thereby preparing crude cyclic ethylene carbonate; then, the crude cyclic ethylene carbonate is subjected to vacuum distillation.

[0082] The cyclic ethylene carbonate obtained by purification in this application has a yield of over 85% and a purity of over 99.7%.

[0083] In some embodiments, the solution containing cyclic ethylene carbonate in S2 is first cooled to room temperature before being purified.

[0084] It should be noted that "room temperature" in this application refers to 15℃~35℃.

[0085] In some embodiments, after the reaction solution in S1 is heated to a preset temperature, the reaction solution is subjected to condensation and reflux treatment.

[0086] In some embodiments, the temperature of the condensation reflux treatment is 0°C to 5°C, including but not limited to 0°C, 1°C, 2°C, 3°C, 4°C, and 5°C.

[0087] The second aspect of this application provides an electrolyte additive comprising cyclic ethylene carbonate prepared according to the preparation method provided in the first aspect of this application.

[0088] Furthermore, this application provides the following specific embodiments and comparative examples to further illustrate the specific implementation of this application and its advantages.

[0089] It should be noted that, unless otherwise specified, all reagents, materials and instruments used in the embodiments and comparative examples provided in this application are commercially available.

[0090] In the following example, the yield is calculated as actual yield / theoretical yield × 100%, and the purity is determined by gas chromatography (GC) with an HP-5 column, a column temperature of 50℃, a retention time of 2 min, a heating rate of 10℃ / min to 150℃, a heating rate of 20℃ / min to 300℃, and a final temperature retention time of 10 min.

[0091] Example 1

[0092] This embodiment provides a method for preparing trifluoromethyldioxane, the specific steps of which are as follows:

[0093] 60.9 g (0.3 mol, 3.0 eq) of ethyl difluorobromoacetate, 45.7 g (0.3 mol, 3.0 eq) of DBU, 14.4 g (0.8 mol, 8.0 eq) of water, and 120 mL of DMF were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was replaced three times with nitrogen to maintain a nitrogen atmosphere. The mixture was then heated to 100 °C, and the reflux condenser was turned on. 11.21 g (0.1 mol, 1.0 eq) of 1,1,1-trifluoro-2,3-epoxypropane was slowly added dropwise at 100 °C over 1.0 h. After the addition was complete, the reaction was maintained at 100 °C for 12 h. GC analysis showed that the 1,1,1-trifluoro-2,3-epoxypropane was completely converted. The reaction solution was cooled to room temperature and subjected to vacuum distillation to obtain 13.82 g of colorless liquid product trifluoromethyldioxane, with a yield of 88.5% and a product purity of 99.9%.

[0094] Relevant reaction formula:

[0095] .

[0096] The characterization data are as follows:

[0097] 1 H-NMR (400MHz, CDCl3): δ 5.04-4.96 (m, 1H), 4.67 (t, J=8.0Hz, 1H), 4.55 (dd, J=8.0Hz, 4.0Hz, 1H). 13 C-NMR (400MHz, CDCl3): δ 152.8, 122.0 (q, 1C), 71.8 (q, 1C), 63.8 (m, 1C). 19 F-NMR (400MHz, CDCl3): δ-80.2. EIMS: m / z (rel intensity) 156 (M + ,4),126(4),107(3),87(100),69(21),43(26),29(17).

[0098] Example 2

[0099] This embodiment provides a method for preparing trifluoromethyldioxane, the specific steps of which are as follows:

[0100] 40.6 g (0.2 mol, 2.0 eq) of ethyl difluorobromoacetate, 30.45 g (0.2 mol, 2.0 eq) of DBU, 18.0 g (1.0 mol, 10.0 eq) of water, and 120 mL of DMF were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was replaced three times with nitrogen to maintain a nitrogen atmosphere. The temperature was then raised to 100 °C, the reflux condenser was turned on, and 11.21 g (0.1 mol, 1.0 eq) of 1,1,1-trifluoro-2,3-epoxypropane was slowly added dropwise at 100 °C over 1.0 h. After the addition was complete, the reaction was maintained at 100 °C for 12 h. GC analysis showed that the 1,1,1-trifluoro-2,3-epoxypropane was completely converted. The reaction solution was cooled to room temperature and subjected to vacuum distillation to obtain 13.3 g of colorless liquid product trifluoromethyldioxane, with a yield of 85.2% and a product purity of 99.8%.

[0101] Relevant reaction formula:

[0102] .

[0103] The characterization data are as follows:

[0104] 1 H-NMR (400MHz, CDCl3): δ 5.04-4.96 (m, 1H), 4.67 (t, J=8.0Hz, 1H), 4.55 (dd, J=8.0Hz, 4.0Hz, 1H). 13 C-NMR (400MHz, CDCl3): δ 152.8, 122.0 (q, 1C), 71.8 (q, 1C), 63.8 (m, 1C). 19 F-NMR (400MHz, CDCl3): δ-80.2. EIMS: m / z (rel intensity) 156 (M + ,4),126(4),107(3),87(100),69(21),43(26),29(17).

[0105] Example 3

[0106] This embodiment provides a method for preparing trifluoromethyldioxane, the specific steps of which are as follows:

[0107] 71.0 g (0.35 mol, 3.5 eq) of ethyl difluorobromoacetate, 47.2 g (0.33 mol, 3.3 eq) of DBU, 12.6 g (0.7 mol, 7.0 eq) of water, and 120 mL of DMF were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was replaced three times with nitrogen to maintain a nitrogen atmosphere. The temperature was then raised to 100 °C, the reflux condenser was turned on, and 11.21 g (0.1 mol, 1.0 eq) of 1,1,1-trifluoro-2,3-epoxypropane was slowly added dropwise at 100 °C over 1.0 h. After the addition was complete, the reaction was maintained at 100 °C for 12 h. GC analysis showed that the 1,1,1-trifluoro-2,3-epoxypropane was completely converted. The reaction solution was cooled to room temperature and subjected to vacuum distillation to obtain 13.7 g of colorless liquid product trifluoromethyldioxane, with a yield of 87.8% and a purity of 99.9%.

[0108] Relevant reaction formula:

[0109] .

[0110] The characterization data are as follows:

[0111] 1 H-NMR (400MHz, CDCl3): δ 5.04-4.96 (m, 1H), 4.67 (t, J=8.0Hz, 1H), 4.55 (dd, J=8.0Hz, 4.0Hz, 1H). 13 C-NMR (400MHz, CDCl3): δ 152.8, 122.0 (q, 1C), 71.8 (q, 1C), 63.8 (m, 1C). 19 F-NMR (400MHz, CDCl3): δ-80.2. EIMS: m / z (rel intensity) 156 (M + ,4),126(4),107(3),87(100),69(21),43(26),29(17).

[0112] Example 4

[0113] This embodiment provides a method for preparing trifluoromethyldioxane, the specific steps of which are as follows:

[0114] 101.49 g (0.5 mol, 5.0 eq) of ethyl difluorobromoacetate, 69.6 g (0.5 mol, 5.0 eq) of TBD, 9.0 g (0.5 mol, 5.0 eq) of water, and 130 mL of DMF were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was replaced three times with nitrogen to maintain a nitrogen atmosphere. The mixture was then heated to 100 °C, and the reflux condenser was turned on. 11.21 g (0.1 mol, 1.0 eq) of 1,1,1-trifluoro-2,3-epoxypropane was slowly added dropwise at 100 °C over 1.0 h. After the addition was complete, the reaction was maintained at 100 °C for 12 h. GC analysis showed that the 1,1,1-trifluoro-2,3-epoxypropane was completely converted. The reaction solution was cooled to room temperature and subjected to vacuum distillation to obtain 13.56 g of colorless liquid product trifluoromethyldioxane, with a yield of 86.9% and a product purity of 99.7%.

[0115] Relevant reaction formula:

[0116] .

[0117] The characterization data are as follows:

[0118] 1 H-NMR (400MHz, CDCl3): δ 5.04-4.96 (m, 1H), 4.67 (t, J=8.0Hz, 1H), 4.55 (dd, J=8.0Hz, 4.0Hz, 1H). 13 C-NMR (400MHz, CDCl3): δ 152.8, 122.0 (q, 1C), 71.8 (q, 1C), 63.8 (m, 1C). 19 F-NMR (400MHz, CDCl3): δ-80.2. EIMS: m / z (rel intensity) 156 (M + ,4),126(4),107(3),87(100),69(21),43(26),29(17).

[0119] Example 5

[0120] This embodiment provides a method for preparing chloromethyldioxane, the specific steps of which are as follows:

[0121] 60.9 g (0.3 mol, 3.0 eq) of ethyl difluorobromoacetate, 45.7 g (0.3 mol, 3.0 eq) of DBU, 16.2 g (0.9 mol, 9.0 eq) of water, and 100 mL of DMF were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was purged three times with nitrogen to maintain a nitrogen atmosphere. The mixture was then heated to 100 °C, the condenser was activated, and 9.3 g (0.1 mol, 1.0 eq) of epichlorohydrin was slowly added dropwise over 30 min. After the addition was complete, the reaction mixture was kept at 100 °C for 10 h. GC analysis showed complete conversion of the epichlorohydrin. The reaction solution was cooled to room temperature and distilled under reduced pressure to obtain 11.82 g of a colorless liquid product, chloromethyldioxane, with a yield of 86.6% and a purity of 99.9%.

[0122] Relevant reaction formula:

[0123] .

[0124] The characterization data are as follows:

[0125] 1 H-NMR (400MHz, CDCl3): δ 5.01-4.95 (m, 1H), 4.56 (t, J=8.0Hz, 1H), 4.37 (dd, J=8.0Hz, 4.0Hz, 1H), 3.80 (dd, J=12.0Hz, 8.0Hz, 1H), 3.70 (dd , J=8.0Hz, 4.0Hz, 1H). 13 C-NMR (400MHz, CDCl3): δ 154.5, 74.5, 67.0, 44.1. EIMS: m / z (rel intensity) 136 (M + ,1),87(100),49(8),43(30),27(7).

[0126] Example 6

[0127] This embodiment provides a method for preparing phenyldioxane, the specific steps of which are as follows:

[0128] 60.9 g (0.3 mol, 3.0 eq) of ethyl difluorobromoacetate, 45.7 g (0.3 mol, 3.0 eq) of DBU, 14.4 g (0.8 mol, 8.0 eq) of water, and 100 mL of DMF were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was purged three times with nitrogen to maintain a nitrogen atmosphere. The mixture was then heated to 100 °C, the condenser was activated, and 12.02 g (0.1 mol, 1.0 eq) of phenyl ethylene oxide was slowly added dropwise over 30 min. After the addition was complete, the reaction mixture was kept at 100 °C for 13 h. GC analysis showed complete conversion of the phenyl ethylene oxide. The reaction solution was cooled to room temperature and purified by vacuum distillation to obtain 14.08 g of a white solid product, phenyldioxane, with a yield of 85.8% and a purity of 99.8%.

[0129] Relevant reaction formula:

[0130] .

[0131] The characterization data are as follows:

[0132] 1 H-NMR (400MHz, CDCl3): δ 7.47-7.42 (m, 3H), 7.41-7.34 (m, 2H), 5.68 (t, J=8.0Hz, 1H), 4.80 (t, J=8.0Hz, 1H), 4.35 (t, J=8.0Hz, 1H). 13 C-NMR (400MHz, CDCl3): δ154.8, 135.8, 129.8, 129.3, 125.9, 78.0, 71.2. EIMS: m / z (rel intensity) 164 (M + ,100),119(14),105(27),90(90),78(52),65(12),51(12).

[0133] Example 7

[0134] This embodiment provides a method for preparing n-butyldioxane, the specific steps of which are as follows:

[0135] 75.3 g (0.3 mol, 3.0 eq) of phenyl 2-bromo-2,2-difluoroacetate, 41.76 g (0.3 mol, 3.0 eq) of TBD, 14.4 g (0.8 mol, 8.0 eq) of water, and 100 mL of acetonitrile were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was replaced three times with nitrogen to maintain a nitrogen atmosphere. The mixture was then heated to 100 °C, the condenser was turned on, and 10.02 g (0.1 mol, 1.0 eq) of 2-butylethylene oxide was slowly added dropwise at 100 °C over 30 min. After the addition was complete, the reaction was maintained at 100 °C for 12 h. GC analysis showed that the 2-butylethylene oxide was completely converted. The reaction solution was cooled to room temperature and subjected to vacuum distillation to obtain 12.58 g of colorless liquid product n-butyldioxane, with a yield of 87.2% and a product purity of 99.9%.

[0136] Relevant reaction formula:

[0137] .

[0138] The characterization data are as follows:

[0139] 1 H-NMR (400MHz, CDCl3): δ 4.75-4.68 (m, 1H), 4.54 (t, J=8.0Hz, 1H), 4.08 (dd, J=4.0Hz, 4.0Hz, 1H), 1.8 6-1.77 (m, 1H), 1.74-1.65 (m, 1H), 1.50-1.32 (m, 4H), 0.93 (t, J=8.0Hz, 3H). 13 C-NMR (400MHz, CDCl3): δ 155.1, 69.4, 62.1, 33.5, 26.4, 22.2, 13.8. EIMS: m / z (rel intensity) 145[(M+H) + ,1],87 (77),67 (39),58 (64),43 (100),29 (23).

[0140] Example 8

[0141] This embodiment provides a method for preparing bromomethyldioxane, the specific steps of which are as follows:

[0142] 75.3 g (0.3 mol, 3.0 eq) of phenyl 2-bromo-2,2-difluoroacetate, 36.65 g (0.3 mol, 3.0 eq) of DMAP, 14.4 g (0.8 mol, 8.0 eq) of water, and 100 mL of acetonitrile were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was replaced three times with nitrogen to maintain a nitrogen atmosphere. The mixture was then heated to 100 °C, the condenser was turned on, and 13.7 g (0.1 mol, 1.0 eq) of epoxypropane was slowly added dropwise at 100 °C over 30 min. After the addition was complete, the reaction was maintained at 100 °C for 12 h. GC analysis showed that the epoxypropane was completely converted. The reaction solution was cooled to room temperature and subjected to vacuum distillation to obtain 15.42 g of colorless liquid product bromomethyldioxane, with a yield of 85.2% and a product purity of 99.9%.

[0143] Relevant reaction formula:

[0144] .

[0145] The characterization data are as follows:

[0146] 1 H-NMR (400MHz, CDCl3): δ 4.98-4.92 (m, 1H), 4.59 (t, J=8.0Hz, 1H), 4.34 (dd, J=8.0Hz, 8.0Hz, 1H), 3.61 (dd, J=8.0Hz, 4.0Hz, 1H). 13 C-NMR (400MHz, CDCl3): δ 154.2, 74.1, 68.2, 31.5. EIMS: m / z (rel intensity) 180 (M + ,11),106(2),87(100),57(8),43(20),27(8).

[0147] Example 9

[0148] This embodiment provides a method for preparing hydroxymethyldioxacyclophenone, the specific steps of which are as follows:

[0149] 75.3 g (0.3 mol, 3.0 eq) of phenyl 2-bromo-2,2-difluoroacetate, 38.77 g (0.3 mol, 3.0 eq) of DIPEA, 14.4 g (0.8 mol, 8.0 eq) of water, and 100 mL of acetonitrile were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was replaced three times with nitrogen to maintain a nitrogen atmosphere. The mixture was then heated to 100 °C, the condenser was turned on, and 7.41 g (0.1 mol, 1.0 eq) of 2,3-epoxypropanol was slowly added dropwise at 100 °C over 30 min. After the addition was complete, the reaction was maintained at 100 °C for 12 h. GC analysis showed that the 2,3-epoxypropanol was completely converted. The reaction solution was cooled to room temperature and subjected to vacuum distillation to obtain 10.19 g of colorless liquid product hydroxymethyldioxacyclophenone, with a yield of 86.3% and a product purity of 99.7%.

[0150] Relevant reaction formula:

[0151] .

[0152] The characterization data are as follows:

[0153] 1 H-NMR (400MHz, CDCl3): δ 4.8-4.78 (m, 1H), 4.52 (t , J=8.0Hz, 1H), 4.46 (dd, J=8.0Hz, 4.0Hz, 1H), 3.98 (dd, J=12.0Hz, 4.0Hz, 1H), 3.70 (dd, J=12.0Hz, 4.0Hz, 1H). 13 C-NMR (400MHz, CDCl3): δ 155.5, 65.8, 61.6, 29.7. EIMS: m / z (rel intensity) 118 (M + ,1),87(65),43(100),31(47).

[0154] Example 10

[0155] This embodiment provides a method for preparing 4-difluoromethyl-1,3-dioxolane-2-one, the specific steps of which are as follows:

[0156] 56.7 g (0.3 mol, 3.0 eq) of methyl 2-bromo-2,2-difluoroacetate, 82.32 g (0.3 mol, 3.0 eq) of BEMP, 14.4 g (0.8 mol, 8.0 eq) of water, and 100 mL of N-methylpyrrolidone were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was replaced three times with nitrogen to maintain a nitrogen atmosphere. The mixture was then heated to 100 °C, the condenser was turned on, and 9.41 g (0.1 mol, 1.0 eq) of 2-(difluoromethyl)ethylene oxide was slowly added dropwise at 100 °C over 30 min. After the addition was complete, the reaction was maintained at 100 °C for 12 h. GC analysis showed that the 2-(difluoromethyl)ethylene oxide was completely converted. The reaction solution was cooled to room temperature and subjected to vacuum distillation to obtain 12.19 g of colorless liquid product 4-difluoromethyl-1,3-dioxolane-2-one, with a yield of 88.3% and a product purity of 99.9%.

[0157] Relevant reaction formula:

[0158] .

[0159] The characterization data are as follows:

[0160] 1 H-NMR (400MHz, CDCl3): δ 5.78-5.69 (m, 1H), 5.65-5.55 (m, 1H), 4.46 (dd, J=8.0Hz, 4.0Hz, 1H), 4.01 (dd, J=8.0Hz, 4.0Hz, 1H).

[0161] Example 11

[0162] This embodiment provides a method for preparing 4-vinyl-1,3-dioxolane-2-one, the specific steps of which are as follows:

[0163] 56.7 g (0.3 mol, 3.0 eq) of methyl 2-bromo-2,2-difluoroacetate, 30.36 g (0.3 mol, 3.0 eq) of triethylamine, 14.4 g (0.8 mol, 8.0 eq) of water, and 100 mL of dimethyl sulfoxide were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was replaced three times with nitrogen to maintain a nitrogen atmosphere. The mixture was then heated to 100 °C, the condenser was turned on, and 7.01 g (0.1 mol, 1.0 eq) of 2-vinyl ethylene oxide was slowly added dropwise at 100 °C over 30 min. After the addition was complete, the reaction was maintained at 100 °C for 12 h. GC analysis showed that the initial methyl 2-bromopropane was completely converted. The reaction solution was cooled to room temperature and subjected to vacuum distillation to obtain 9.97 g of colorless liquid product 4-vinyl-1,3-dioxolane-2-one, with a yield of 87.4% and a product purity of 99.8%.

[0164] Relevant reaction formula:

[0165] .

[0166] The characterization data are as follows:

[0167] 1 H-NMR (400MHz, CDCl3): δ 5.86-5.76 (m, 1H), 5.38-5.28 (m, 2H), 4.86-4.75 (m, 1H), 4.33 (dd, J=8.0Hz, 4.0Hz, 1H), 4.08 (dd, J=8.0Hz, 4.0Hz, 1H).

[0168] Example 12

[0169] This embodiment provides a method for preparing 4-chloro-1,3-dioxolane-2-one, the specific steps of which are as follows:

[0170] 60.5 g (0.32 mol, 3.2 eq) of methyl 2-bromo-2,2-difluoroacetate, 82.32 g (0.3 mol, 3.0 eq) of BEMP, 16.2 g (0.9 mol, 9.0 eq) of water, and 100 mL of N-methylpyrrolidone were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was replaced three times with nitrogen to maintain a nitrogen atmosphere. The mixture was then heated to 100 °C, the condenser was turned on, and 7.85 g (0.1 mol, 1.0 eq) of 2-chloroethylene oxide was slowly added dropwise at 100 °C over 30 min. After the addition was complete, the reaction was maintained at 100 °C for 12 h. GC analysis showed that the 2-chloroethylene oxide was completely converted. The reaction solution was cooled to room temperature and subjected to vacuum distillation to obtain 10.61 g of colorless liquid product 4-chloro-1,3-dioxolane-2-one, with a yield of 86.6% and a product purity of 99.8%.

[0171] The characterization data are as follows:

[0172] 1 H-NMR (400MHz, CDCl3): δ4.626-4.657 (dt, J=-10.2Hz, 5.7Hz, 1H), 4.889-4.915 (dt, J=-10.2Hz, 2.0Hz, 1H), 6.495-6.514 (t, J=5.7Hz, 2.0Hz, 1H).

[0173] Relevant reaction formula:

[0174] .

[0175] Example 13

[0176] This embodiment provides a method for preparing 4-(phenylethynyl)-1,3-dioxolane-2-one, the specific steps of which are as follows:

[0177] 65.0 g (0.32 mol, 3.2 eq) of ethyl 2-bromo-2,2-difluoroacetate, 44.54 g (0.32 mol, 3.2 eq) of TBD, 14.4 g (0.8 mol, 8.0 eq) of water, and 100 mL of N-methylpyrrolidone were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was replaced three times with nitrogen to maintain a nitrogen atmosphere. The mixture was then heated to 100 °C, the condenser was turned on, and 14.42 g (0.1 mol, 1.0 eq) of 2-(phenylethynyl)ethylene oxide was slowly added dropwise at 100 °C over 30 min. After the addition was complete, the reaction was maintained at 100 °C for 12 h. GC analysis showed that the 2-(phenylethynyl)ethylene oxide was completely converted. The reaction solution was cooled to room temperature and subjected to vacuum distillation to obtain 16.04 g of a yellow oily product, 4-(phenylethynyl)-1,3-dioxolane-2-one, with a yield of 85.2% and a purity of 99.9%.

[0178] The characterization data are as follows:

[0179] 1 H-NMR (400MHz, CDCl3): δ7.46-7.44 (m, 2 H), 7.40-7.31 (m, 3 H), 5.53 (dd, J=8.2Hz, 6.9Hz, 1H), 4.69 (t, J= 8.2Hz, 1H), 4.48 (dd, J=8.2Hz, 6.9Hz,1H). 13 C-NMR (100 MHz, CDCl3,): δ153.9, 131.9,129.7, 128.5, 120.6, 89.8,81.7, 69.7, 66.6.

[0180] Relevant reaction formula:

[0181] .

[0182] Example 14

[0183] This embodiment provides a method for preparing 4-methoxy-1,3-dioxolane-2-one, the specific steps of which are as follows:

[0184] 60.9 g (0.3 mol, 3.0 eq) of ethyl difluorobromoacetate, 45.7 g (0.3 mol, 3.0 eq) of DBU, 14.4 g (0.8 mol, 8.0 eq) of water, and 100 mL of DMF were added to a 250 mL reaction flask equipped with a reflux condenser. The air in the reaction flask was replaced three times with nitrogen to maintain a nitrogen atmosphere. The mixture was then heated to 100 °C, the condenser was turned on, and 7.41 g (0.1 mol, 1.0 eq) of 2-methoxyethylene oxide was slowly added dropwise at 100 °C over 30 min. After the addition was complete, the reaction was maintained at 100 °C for 12 h. GC analysis showed that the 2-methoxyethylene oxide was completely converted. The reaction solution was cooled to room temperature and subjected to vacuum distillation to purify 10.11 g of colorless liquid product 4-methoxy-1,3-dioxolane-2-one, with a yield of 85.6% and a purity of 99.8%.

[0185] Relevant reaction formula:

[0186] .

[0187] The characterization data are as follows:

[0188] 1 H-NMR (400MHz, CDCl3): δ3.46-3.44 (s, 3H), 4.19-4.22 (m, J= -12.4Hz, 7.0Hz, 1H), 4.43-4.47 (m, J= -12.4Hz, 4.5Hz, 1H), 5.98-6.02 (t, J=7.0 Hz, 4.5Hz, 1H).

[0189] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0190] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing cyclic ethylene carbonate, characterized in that, Includes the following steps: Difluorocarbene was prepared by reacting the compound shown in formula (I) in the presence of a base and at a predetermined temperature; The difluorocarbene was reacted with the compound shown in formula (II) in the presence of water and a base to prepare the cyclic ethylene carbonate; the structural formula of the cyclic ethylene carbonate is shown in formula (V). ； ； ； Wherein, R is selected from any one of substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl and substituted or unsubstituted aryl; R f It is selected from any one of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, halogen, nitro, substituted or unsubstituted amino, substituted or unsubstituted alkoxy, substituted or unsubstituted imidazolyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted thiophene, and substituted or unsubstituted furanyl.

2. The method for preparing cyclic ethylene carbonate according to claim 1, characterized in that, Includes the following steps: The compound shown in formula (I) is mixed with a base, an organic solvent and water, and heated to a preset temperature to prepare a solution containing difluorocarbene; The cyclic ethylene carbonate is prepared by reacting the compound of formula (II) with the difluorocarbene-containing solution.

3. The method for preparing cyclic ethylene carbonate according to claim 2, characterized in that, The compound represented by formula (II) was added dropwise to the solution containing difluorocarbene.

4. The method for preparing cyclic ethylene carbonate according to any one of claims 1 to 3, characterized in that, The base includes one or more of triethylamine, diisopropylethylamine, pyridine, imidazole, piperidine, pyrrole, 1,8-diazabicycloundec-7-ene, 4-dimethylaminopyridine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphide.

5. The method for preparing cyclic ethylene carbonate according to any one of claims 1 to 3, characterized in that, The preset temperature is 50℃~150℃.

6. The method for preparing cyclic ethylene carbonate according to claim 2, characterized in that, The molar ratio of the compound represented by formula (I) to the compound represented by formula (II) is (2~5):

1.

7. The method for preparing cyclic ethylene carbonate according to claim 2, characterized in that, The molar ratio of the base to the compound represented by formula (II) is (2~5):

1.

8. The method for preparing cyclic ethylene carbonate according to claim 2, characterized in that, The molar ratio of water to the compound represented by formula (II) is (5~10):

1.

9. The method for preparing cyclic ethylene carbonate according to any one of claims 1 to 3, characterized in that, The reaction process for preparing the cyclic ethylene carbonate was carried out under a nitrogen atmosphere.

10. An electrolyte additive, characterized in that, The electrolyte additive includes cyclic ethylene carbonate prepared by the preparation method according to any one of claims 1 to 9.

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