Method for preparing high-purity 1, 4-dioxane-2-ketone at low cost

Abstract

The invention belongs to the field of chemistry and chemical engineering, and discloses a method for preparing high-purity 1, 4-dioxane-2-ketone at low cost. A large amount of high-purity 1, 4-dioxane-2-ketone can be prepared at one time by taking a large amount of glycollic acid or glycollic acid derivatives and ethylene oxide as raw materials and adopting a one-step synthesis process route and a purification mode suitable for industrial production. According to the method, cheap bulk commodities are adopted as raw materials, and high-value conversion of low-value chemicals is achieved; according to the method disclosed by the invention, the 1, 4-dioxane-2-ketone is rapidly synthesized in one step under mild conditions without a catalyst or with a trace amount of a catalyst, so that the synthesis yield of a target product is improved, the reaction steps are greatly shortened, the energy consumption is greatly reduced, and the production cost is obviously reduced.

Description

Technical Field

[0001] The present invention relates to the field of chemistry and chemical engineering, and in particular to a method for preparing high-purity 1,4-dioxane-2-one at low cost. Background Art

[0002] 1,4-Dioxane-2-one (pDO) is a colorless crystal at room temperature with a molecular weight of 102 Da, a melting point of 26-28°C, and a boiling point of 220°C at normal pressure. pDO is an important chemical used as a mildew inhibitor and a monomer in the synthesis of poly(1,4-dioxane-2-one) (PpDO), a biodegradable polyester material. The primary prerequisite for preparing high-performance PpDO is the availability of high-purity monomer pDO on a large scale. However, pDO is not yet readily available in large quantities for commercial production. Therefore, the development of novel pDO synthesis methods and process routes is a pressing technical challenge.

[0003] Currently, there are two main methods for synthesizing pDO: one uses diethylene glycol as a starting material and produces pDO through a catalytic oxidative dehydrogenation cyclization reaction; the other uses ethylene glycol as a starting material and reacts it with chloroacetic acid or a chloroacetate salt to produce a hydroxy acid salt, which is then esterified and cyclized. However, each of these methods has its own advantages and disadvantages. For example, patents US2807629 and US2900395 disclose methods for synthesizing pDO based on the catalytic dehydrogenation of diethylene glycol. These methods primarily use copper and chromium as catalysts and typically require temperatures maintained at 240-360°C. However, the yield of pure pDO is only 25%. Academician Wang Yuzhong's team further optimized the reaction process, using copper and zinc compounds as catalysts and alkali, alkaline earth, and rare earth metal compounds as co-catalysts, which has improved the yield to a certain extent. However, this method is difficult to separate and purify pDO, and the reaction apparatus and catalyst structure are relatively complex, resulting in high industrial production costs. Furthermore, it is difficult to ensure that the pDO product is free of heavy metal residues, which has an impact on the subsequent catalytic ring-opening polymerization of pDO and its medical applications.

[0004] Alternatively, using ethylene glycol as a raw material, monosodium ethylene glycol can be prepared in the presence of metallic sodium. This can then be reacted with chloroacetic acid to produce sodium hydroxyethoxyacetic acid. After distillation and washing, pDO can be prepared by acidification with an inorganic acid or high-temperature catalytic ring closure. However, this method produces a large amount of sodium chloride during the preparation process, resulting in complex steps and harsh reaction conditions. Furthermore, the chloroacetic acid hydrolysis process is highly corrosive and polluting, making it unsuitable for large-scale production.

[0005] Therefore, it is very meaningful to explore a simple pDO synthesis process, improve the yield and purity of pDO, and reduce or abandon the use of expensive catalysts or heavy metal catalysts. Summary of the Invention

[0006] The embodiment of the present invention provides a method for preparing high-purity 1,4-dioxane-2-one at low cost, which can produce high-yield and high-purity 1,4-dioxane-2-one through a one-step synthesis method.

[0007] In a first aspect, the present invention provides a method for preparing high-purity 1,4-dioxane-2-one at low cost, the method comprising:

[0008] Ethylene oxide is mixed with glycolic acid or a glycolic acid derivative, and the high-purity 1,4-dioxane-2-one is obtained after reaction; wherein the glycolic acid derivative includes glycolate or glycolate ester, and the structural formula of the glycolate ester is as follows:

[0009] In the formula, R is a C1-C8 alkyl group, a C3-C8 cycloalkyl group, an aromatic group or an aromatic heterocyclic group having a substituent, and the substituent is a halogen, a C1-C3 alkyl group, a halogenated C1-C3 alkyl group, a C1-C3 alkoxy group or a hydroxyl group.

[0010] Preferably, before the reaction is carried out, the step of adding a catalyst to the reaction system is further included; wherein the catalyst is selected from an inorganic acid catalyst, an organic acid catalyst, an inorganic base catalyst, an organic base catalyst, a metal chloride catalyst, a metal oxide catalyst, a metal salt catalyst, an ionic liquid catalyst, a solid acid catalyst, a Lewis acid-base pair catalyst, a cation exchange resin catalyst or a molecular sieve catalyst.

[0011] Preferably, the molar ratio of the catalyst to glycolic acid or glycolic acid derivative is 1:(20-10000).

[0012] More preferably, the molar ratio of the catalyst to glycolic acid or glycolic acid derivative is 1:(100-500).

[0013] Preferably, the glycolate is selected from one or more of lithium glycolate, sodium glycolate, potassium glycolate, calcium glycolate, magnesium glycolate, aluminum glycolate or iron glycolate.

[0014] More preferably, the glycolate is selected from one or more of methyl glycolate, ethyl glycolate, n-propyl glycolate, isopropyl glycolate, n-butyl glycolate, isobutyl glycolate, tert-butyl glycolate, phenyl glycolate or benzyl glycolate.

[0015] Preferably, the molar ratio of ethylene oxide to glycolic acid or glycolic acid derivative is (1-10):(1-10).

[0016] More preferably, the molar ratio of ethylene oxide to glycolic acid or glycolic acid derivative is 1:(1-5).

[0017] Preferably, the inorganic acid catalyst is selected from one or more of sulfuric acid, hydrochloric acid, hydrobromic acid, tungstic acid, titanic acid, and boric acid;

[0018] The organic acid catalyst is selected from one or more of methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, boron trifluoride, boron trifluoride ethyl ether, tris(pentafluorophenyl)boron, triethylboron, camphorsulfonic acid, benzoic acid, salicylic acid, oxalic acid, and malic acid;

[0019] The inorganic base catalyst is selected from one or more of sodium carbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, lithium hydroxide, magnesium hydroxide, zinc hydroxide, copper hydroxide, iron hydroxide, and ammonium hydroxide;

[0020] The organic base catalyst is selected from one or more of triethylamine, pyridine, 4-dimethylaminopyridine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and hexamethyldisilazane;

[0021] The metal chloride catalyst is selected from one or more of ferric chloride, ferric dichloride, zinc dichloride, tin chloride, magnesium chloride, titanium chloride, aluminum chloride, and indium chloride;

[0022] The metal oxide catalyst is selected from one or more of iron oxide, ferroferric oxide, copper oxide, magnesium oxide, zinc oxide, aluminum oxide, calcium oxide, and titanium oxide;

[0023] The metal salt catalyst is selected from one or more of copper tetrafluoroborate, bismuth trifluoride, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, calcium carbonate, cesium carbonate, sodium glycolate, sodium acetate, lithium diisopropylamide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium tert-butoxide, n-butyl lithium, and isobutyl lithium;

[0024] The ionic liquid catalyst is selected from one or more of imidazole ionic liquids, pyridine ionic liquids, quaternary ammonium salt ionic liquids, and quaternary phosphonium salt ionic liquids;

[0025] The Lewis acid-base catalyst is obtained by mixing a Lewis acid and a Lewis base; wherein the Lewis acid is selected from one or more of methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, boron trifluoride, boron trifluoride ethyl ether, tris(pentafluorophenyl)boron, triethylboron, camphorsulfonic acid, benzoic acid, ferric chloride, ferric dichloride, zinc dichloride, tin chloride, magnesium chloride, titanium chloride, aluminum chloride, indium chloride, and diethylzinc; and the Lewis base is selected from one or more of triethylamine, ammonia monohydrate, pyridine, 4-dimethylaminopyridine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, hexamethyldisilazane, and carbene;

[0026] The cation exchange resin is selected from one or more of a strongly acidic styrene-based cation exchange resin, a weakly acidic styrene-propylene-based cation exchange resin, a styrene divinylbenzene resin, and an acrylic acid-based cation exchange resin;

[0027] The molecular sieve catalyst is selected from one or more of zirconium sulfate molecular sieve, beta molecular sieve, LaY molecular sieve, TS-1 molecular sieve, USY molecular sieve, and ZSM-5 molecular sieve.

[0028] More preferably, the catalyst is selected from an inorganic acid catalyst, an organic acid catalyst, a metal chloride catalyst, a metal oxide catalyst, a metal salt catalyst, a solid acid catalyst or a Lewis acid-base pair catalyst.

[0029] Preferably, the reaction temperature is -50 to 100°C and the reaction time is 10 to 60 minutes.

[0030] Preferably, after the reaction is completed, the process further comprises filtering, washing, distilling and crystallizing the crude product obtained from the reaction.

[0031] Preferably, the catalyst is selected from one or more of anion exchange resin catalysts, ammonium salt catalysts, quaternary ammonium salt catalysts, polyquaternary ammonium salt catalysts or quaternary phosphonium salt catalysts.

[0032] More preferably, the anion exchange resin catalyst is selected from one or more of a strongly basic ion exchange resin, a weakly basic ion exchange resin, a supported quaternary ammonium salt or a supported quaternary phosphonium salt;

[0033] The ammonium salt catalyst is selected from one or more of ammonium fluoride, ammonium chloride, ammonium bromide or ammonium iodide;

[0034] The structural formula of the quaternary ammonium salt catalyst is as follows:

[0035] R is a C1-C 22 Alkyl, aromatic group with substituent or aromatic heterocyclic group with substituent; the substituent is C1-C 10 Alkyl, C1-C 10 Alkoxy or hydroxy, the heteroatom in the aromatic heterocyclic group is nitrogen, sulfur or oxygen; X is fluoride, chloride, bromide, iodide, acetate, sulfate, sulfite, bisulfate, nitrate, nitrite, carbonate, bicarbonate, sulfonate or p-toluenesulfonate;

[0036] The polyquaternium salt catalyst is selected from one or more of polydimethyldiallylammonium chloride, polyquaternium-10 or polyquaternium-55;

[0037] The structural formula of the quaternary phosphonium salt catalyst is as follows:

[0038] R is a C1-C 22 Alkyl, aromatic group with substituent or aromatic heterocyclic group with substituent; the substituent is C1-C 10 Alkyl, C1-C 10 The heteroatom in the aromatic heterocyclic group is nitrogen, sulfur or oxygen, and X is fluoride, chloride, bromide or iodide.

[0039] The sulfonium salt catalyst is selected from the ammonium salt catalyst selected from one or more of trimethylsulfonium bromide, trimethylsulfonium iodide, trimethylsulfonium tetrafluoroborate, triethylsulfonium iodide, triphenylsulfonium chloride, triphenylsulfonium bromide, and triphenylsulfonium trifluoromethanesulfonate.

[0040] More preferably, the molar ratio of the catalyst to glycolic acid or glycolic acid derivative is 1:(20-10000).

[0041] More preferably, the molar ratio of ethylene oxide to glycolic acid or glycolic acid derivative is (1-10):(1-10).

[0042] More preferably, the reaction temperature is 25-100° C. and the reaction time is 10 min-6 h.

[0043] Preferably, after adding the catalyst to the reaction system, the step of adding an organic solvent to the reaction system is further included: wherein the organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, tetrahydrofuran, dioxane, dichloroethane, chloroform, carbon tetrachloride, toluene, xylene, and trimethylbenzene.

[0044] In a second aspect, the present invention provides a high-purity 1,4-dioxane-2-one prepared by any of the methods described in the first aspect.

[0045] Compared with the prior art, the present invention has at least the following beneficial effects:

[0046] (1) In the present invention, by using glycolic acid or glycolic acid derivatives and ethylene oxide as raw materials and adopting a one-step synthetic process route, high-purity 1,4-dioxane-2-one can be prepared in large quantities at one time. The reaction raw materials used are all low-cost bulk chemicals, which reduces product cost, has high added value, and has a wide source of raw materials, avoiding the problem of being restricted by the source of raw materials. This provides a practical method for the industrial production of 1,4-dioxane-2-one;

[0047] (2) The one-step method for preparing 1,4-dioxane-2-one avoids complex synthesis processes and harsh reaction conditions, resulting in a short reaction time, high yield, and low energy consumption. Furthermore, the reaction is carried out under air conditions, reducing the use of inert gas. At the same time, the reaction conditions are normal pressure, reducing safety hazards.

[0048] (3) In a preferred embodiment, the reaction process of ethylene oxide and glycolic acid or glycolic acid derivatives is catalyzed by a catalyst, which can further accelerate the reaction rate, improve the reaction yield, and reduce the production cost of 1,4-dioxane-2-one. In addition, the catalysts used are bulk chemicals, have no heavy metal residues, are less corrosive to synthesis equipment, and are suitable for large-scale industrial production conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0050] Figure 1 This is the nuclear magnetic spectrum of a high-purity 1,4-dioxane-2-one provided in Example 11 of the present invention;

[0051] Figure 2 This is an infrared spectrum of a high-purity 1,4-dioxane-2-one provided in Example 11 of the present invention; wherein the abscissa is the wave number and the ordinate is the transmittance;

[0052] Figure 3 This is a melting point test spectrum of a high-purity 1,4-dioxane-2-one provided in Example 11 of the present invention; wherein the abscissa is temperature and the ordinate is heat flow rate;

[0053] Figure 4 This is the nuclear magnetic spectrum of high-purity 1,4-dioxane-2-one provided in Example 32 of the present invention. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0055] Ethylene oxide is the simplest ternary ether compound, primarily used in the production of reagents such as ethylene glycol, surfactants, ethanolamine, and glycol ethers. It is also widely used in the synthesis of materials for daily chemicals, pharmaceuticals, pesticides, and polyether polyols. It can also be used as a disinfectant for high-end medical devices. Glycolic acid is an important, high-value-added chemical, widely used in industrial cleaning agents, daily chemical raw materials, electroplating surface treatment fluids, fungicides, and biodegradable materials. Furthermore, glycolic acid esters, as glycolic acid derivatives, possess improved solubility and stability, while possessing the chemical properties of both alcohols and esters, capable of undergoing reactions such as hydrolysis, oxidation, reduction, carbonylation, amination, and alcoholysis. As an important bulk chemical raw material, they are widely used in the chemical, pharmaceutical, and pesticide industries.

[0056] Selifonov Sergey A. previously synthesized six-membered heterocyclic ether esters using lactate and epoxide as raw materials via an epoxy ring-opening-saponification-hydrolysis-condensation cyclization process. This method first catalyzed the synthesis of a 2-(2-hydroxyethyl)-propionic acid intermediate from lactate and epoxide, then subjected the intermediate to base-catalyzed saponification or esterase-catalyzed hydrolysis to synthesize 2-(2-hydroxyethyl)-propionic acid, and finally, condensed the hydroxycarboxyl groups to synthesize the six-membered heterocyclic ether ester. However, while this method was capable of preparing cyclic ether ester monomers, the synthesis process was overly complex, and the thermodynamic instability of the seven-membered ring made it difficult to achieve cyclization through a one-step reaction of the hydroxyester and epoxide. Furthermore, the presence of a methyl group in the lactate may hinder the nucleophilic reaction of the hydroxyl group, necessitating a stepwise method using a condensation reagent for cyclization.

[0057] Leyva-Perez has used nano-titanium dioxide to catalyze the reaction of water with primary and secondary alcohols to complete the hydration and alkoxylation of epoxy compounds, and used glycolic acid and several epoxides to selectively synthesize 1,4-dioxane-2-one derivatives. However, the nano-titanium dioxide used as a catalyst has high manufacturing costs, and the catalyst occupies 40% of the mass fraction of the reaction substrate. Since titanium dioxide is not resistant to water and oxygen, high-pressure nitrogen is required for the reaction; due to the low catalytic activity of titanium dioxide, a high temperature reaction of more than 120°C is required; the reaction requires the addition of an organic solvent, and is difficult to apply to large-scale synthesis.

[0058] Based on the above problems, and addressing the current high cost of pDO caused by complicated production processes, harsh reaction conditions, low yields, and expensive catalysts, as well as the problem of metal residues making subsequent products potentially harmful, the present invention considers using bulk chemicals such as glycolic acid and its derivatives and ethylene oxide as raw materials to develop a simple pDO synthesis process. This not only reduces the production cost of pDO, but also realizes the high-value utilization of low-value chemicals, which has important strategic significance and economic value for meeting market demand and developing new biodegradable materials.

[0059] like Figure 1 As shown, the present invention provides a method for preparing high-purity 1,4-dioxane-2-one at low cost, the method comprising:

[0060] Ethylene oxide is mixed with glycolic acid or a glycolic acid derivative, and the high-purity 1,4-dioxane-2-one is obtained after reaction; wherein the glycolic acid derivative includes glycolate or glycolate ester, and the structural formula of the glycolate ester is as follows:

[0061] In the formula, R is a C1-C8 alkyl group with a substituent, a C3-C8 cycloalkyl group with a substituent, an aromatic group with a substituent, or an aromatic heterocyclic group with a substituent, and the substituent is a halogen, a C1-C3 alkyl group, a halogenated C1-C3 alkyl group, a C1-C3 alkoxy group, or a hydroxyl group.

[0062] In an embodiment of the present invention, glycolic acid or a glycolic acid derivative and ethylene oxide are used as raw materials, and the reaction temperature is controlled so that the above reactants themselves undergo autocatalysis under hydrogen bond interaction. In addition, the carboxylic acid group in the glycolic acid can act as a catalyst to achieve an autocatalytic reaction. In this way, a one-step synthesis process route can be used to prepare high-purity 1,4-dioxane-2-one in large quantities at one time. The reaction raw materials used are all low-cost bulk chemicals, which reduces product costs, increases product added value, and has a wide source of raw materials, avoiding the problem of being restricted by raw material sources. This provides a practical method for the industrial production of 1,4-dioxane-2-one.

[0063] Taking glycolic acid derivatives as glycolate as an example, the synthetic route of 1,4-dioxane-2-one is as follows:

[0064]

[0065] As can be seen from the above reaction formula, using bulk chemicals glycolate and ethylene oxide as reaction raw materials, glycolate contains hydroxyl groups that can participate in the reaction, which can undergo a ring-opening reaction with ethylene oxide, and glycolate contains ester bonds that can undergo intramolecular ester exchange reaction, thereby forming 1,4-dioxane-2-one through a one-step cascade reaction.

[0066] In the examples of the present invention, extensive research was conducted on the design of a route for synthesizing pDO from glycolic acid or glycolic acid derivatives and epoxides. It was found that glycolic acid or glycolic acid derivatives without any substituents can react with ethylene oxide to produce pDO in a single step. Through comprehensive control and selection of various reaction raw materials, catalyst type, process reaction conditions, synthesis scale, etc., the synthesis process flow and production cost of pDO were greatly reduced.

[0067] It should be noted that, in the embodiments of the present invention, ethylene oxide can be in a liquid state, a gaseous state, or configured as a solution dissolved in an organic solvent; when ethylene oxide is a solution, the organic solvent is selected from one or more of tetrahydrofuran, dioxane, ether, dichloromethane, dichloroethane, chloroform, carbon tetrachloride, toluene, xylene, and trimethylbenzene.

[0068] According to some preferred embodiments, the glycolate salt is selected from one or more of lithium glycolate, sodium glycolate, potassium glycolate, calcium glycolate, magnesium glycolate, aluminum glycolate or iron glycolate; the glycolate ester is selected from one or more of methyl glycolate, ethyl glycolate, n-propyl glycolate, isopropyl glycolate, n-butyl glycolate, isobutyl glycolate, tert-butyl glycolate, phenyl glycolate or benzyl glycolate.

[0069] In the embodiment of the present invention, when the glycolate and glycolate ester in the glycolic acid derivative are of the above types, it is more conducive to quickly synthesizing a large amount of 1,4-dioxane-2-one through reaction with ethylene oxide.

[0070] According to some preferred embodiments, the molar ratio of ethylene oxide to glycolic acid or glycolic acid derivative is (1-10):(1-10) (for example, it can be 1:1, 1:2, 1:5, 1:8, 1:10, 5:1, 8:1, 10:1, 5:2, 5:5, 8:5 or 10:10).

[0071] Experiments in the present invention have confirmed that due to the competitive ring-opening polymerization side reaction of ethylene oxide during the reaction of ethylene oxide with glycolic acid or glycolic acid derivatives, byproducts such as polyethylene glycol oligomers are produced, making purification difficult and reducing the effective conversion rate of ethylene oxide. Therefore, in the embodiments of the present invention, by screening the temperature, addition method, and reaction mode, namely, adopting room temperature or low temperature, slow dropwise addition, shortening the reaction time, etc., the molar ratio of ethylene oxide to glycolic acid or glycolic acid derivative is rationally controlled. Ultimately, it is achieved that the occurrence of side reactions can be significantly reduced under conditions of low proportions of glycolic acid or glycolic acid derivatives. In the embodiments of the present invention, the molar ratio of ethylene oxide to glycolic acid or glycolic acid derivatives is further preferably 1:(1-5), and an excess of glycolic acid or glycolic acid derivatives is used to suppress the occurrence of side reactions, thereby facilitating the reduction of the production of byproducts such as oligomeric polyethers during the reaction, and thus facilitating the production of high-yield and high-purity 1,4-dioxane-2-one.

[0072] According to some preferred embodiments, the step of adding a catalyst to the reaction system is further included before the reaction is carried out.

[0073] In the embodiments of the present invention, experimental verification has found that the hydroxyl groups in the reaction raw materials of glycolic acid and glycolic acid derivatives that can participate in the reaction can undergo a highly selective ring-opening reaction with ethylene oxide under the catalytic action of a certain catalyst, thereby synthesizing 1,4-dioxane-2-one through a one-pot two-step process. After adding the catalyst, the reaction time for the synthesis of 1,4-dioxane-2-one can be significantly shortened, and the yield can be significantly improved, with the yield reaching as high as over 99%.

[0074] According to some preferred embodiments, the catalyst is selected from an inorganic acid catalyst, an organic acid catalyst, an inorganic base catalyst, an organic base catalyst, a metal chloride catalyst, a metal oxide catalyst, a metal salt catalyst, an ionic liquid catalyst, a solid acid catalyst, a Lewis acid-base pair catalyst, a cation exchange resin catalyst or a molecular sieve catalyst.

[0075] Experiments of the present invention have confirmed that when ethylene oxide reacts with glycolic acid or glycolic acid derivatives, adding a trace amount of a series of low-cost chemicals such as inorganic acids, organic acids, inorganic bases, organic bases, metal chlorides, metal oxides, metal salts and ionic liquids as catalysts can significantly reduce the reaction temperature, accelerate the reaction rate, and reduce the reaction time, thereby increasing the reaction yield and reducing production costs.

[0076] According to some preferred embodiments, the inorganic acid catalyst is selected from one or more of sulfuric acid, hydrochloric acid, hydrobromic acid, tungstic acid, titanic acid, and boric acid;

[0077] The organic acid catalyst is selected from one or more of methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, boron trifluoride, boron trifluoride ethyl ether, tris(pentafluorophenyl)boron, triethylboron, camphorsulfonic acid, benzoic acid, salicylic acid, oxalic acid, and malic acid;

[0078] The inorganic base catalyst is selected from one or more of sodium carbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, lithium hydroxide, magnesium hydroxide, zinc hydroxide, copper hydroxide, iron hydroxide, and ammonium hydroxide;

[0079] The organic base catalyst is selected from one or more of triethylamine, pyridine, 4-dimethylaminopyridine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and hexamethyldisilazane;

[0080] The metal chloride catalyst is selected from one or more of ferric chloride, ferric dichloride, zinc dichloride, tin chloride, magnesium chloride, titanium chloride, aluminum chloride, and indium chloride; the metal oxide catalyst is selected from one or more of ferric oxide, ferroferric oxide, copper oxide, magnesium oxide, zinc oxide, aluminum oxide, calcium oxide, and titanium oxide;

[0081] The metal salt catalyst is selected from one or more of copper tetrafluoroborate, bismuth trifluoride, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, calcium carbonate, cesium carbonate, sodium glycolate, sodium acetate, lithium diisopropylamide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium tert-butoxide, n-butyl lithium, and isobutyl lithium;

[0082] The ionic liquid catalyst is selected from one or more of imidazole ionic liquids, pyridine ionic liquids, quaternary ammonium salt ionic liquids, and quaternary phosphonium salt ionic liquids;

[0083] The Lewis acid-base catalyst is obtained by mixing a Lewis acid and a Lewis base; wherein the Lewis acid is selected from one or more of methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, boron trifluoride, boron trifluoride ethyl ether, tris(pentafluorophenyl)boron, triethylboron, camphorsulfonic acid, benzoic acid, ferric chloride, ferric dichloride, zinc dichloride, tin chloride, magnesium chloride, titanium chloride, aluminum chloride, indium chloride, and diethylzinc; and the Lewis base is selected from one or more of triethylamine, ammonia monohydrate, pyridine, 4-dimethylaminopyridine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, hexamethyldisilazane, and carbene;

[0084] The cation exchange resin is selected from one or more of a strongly acidic styrene-based cation exchange resin, a weakly acidic styrene-propylene-based cation exchange resin, a styrene divinylbenzene resin, and an acrylic acid-based cation exchange resin;

[0085] The molecular sieve catalyst is selected from one or more of zirconium sulfate molecular sieve, beta molecular sieve, LaY molecular sieve, TS-1 molecular sieve, USY molecular sieve, and ZSM-5 molecular sieve.

[0086] According to some preferred embodiments, the catalyst is selected from an inorganic acid catalyst, an organic acid catalyst, a metal chloride catalyst, a metal oxide catalyst, a metal salt catalyst, a solid acid catalyst or a Lewis acid-base pair catalyst.

[0087] In an embodiment of the present invention, a large number of catalysts are first screened, and it is found that the above-mentioned types of catalysts can further effectively catalyze the reaction of ethylene oxide with glycolic acid or glycolic acid derivatives. Then, through the comprehensive control of a series of conditions such as temperature, feed ratio, reaction mode, etc., the catalyst can maintain high catalytic activity even when the amount used is small (the amount used is less than 1%). In this way, not only can the reaction temperature and reaction time be significantly lowered, but also the purification difficulty and catalyst residue can be further reduced while ensuring a lower cost.

[0088] In the embodiment of the present invention, the organic base catalyst may also be a phosphazene base or a guanidine. For example, the phosphazene base may specifically be a phosphazene base P1-t-Bu, a phosphazene base P2-t-Bu, a phosphazene base P4-t-Bu, hexamethylphosphazene triamine, hexaphenoxycyclotriphosphazene or a fluorophosphazene base, and the guanidine may specifically be guanidine hydrochloride, diphenylguanidine, tetramethylguanidine, dimethylguanidine, and the like.

[0089] According to some preferred embodiments, when the catalyst is selected from one or more of an inorganic acid catalyst, an organic acid catalyst, an inorganic base catalyst, an organic base catalyst, a metal chloride catalyst, a metal oxide catalyst, a metal salt catalyst, an ionic liquid catalyst, a solid acid catalyst, a Lewis acid-base pair catalyst, a cation exchange resin catalyst or a molecular sieve catalyst:

[0090] The molar ratio of the catalyst to glycolic acid or glycolic acid derivative is 1:(20-10000) (for example, 1:20, 1:50, 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900, 1:1000, 1:2000, 1:3000, 1:4000, 1:5000, 1:6000, 1:7000, 1:8000, 1:9000 or 1:10000).

[0091] In the embodiments of the present invention, the specific amounts of different catalysts can be adjusted within the above-mentioned range based on the activity of each catalyst. Highly active catalysts (such as inorganic acids, organic acids, and metal chlorides) can achieve a good catalytic effect at lower concentrations, while low-activity catalysts (such as metal salts, organic bases, and inorganic bases) require higher concentrations to achieve a good catalytic effect. Furthermore, when selecting a catalyst, the catalyst's activity life should also be considered (for example, solid acid catalysts can be reused). Generally speaking, within a certain range, the more a catalyst is used, the higher the catalytic activity and the faster the reaction. However, for certain catalysts (such as strongly acidic inorganic acids and strongly basic inorganic bases), exceeding a certain amount can cause side reactions. Therefore, in the embodiments of the present invention, the molar ratio of catalyst to glycolic acid or glycolic acid derivative is controlled in accordance with the principle of minimum cost, so that the reaction efficiency of ethylene oxide with glycolic acid or glycolic acid derivative can be improved by using less catalyst. Furthermore, in the embodiments of the present invention, the molar ratio of catalyst to glycolic acid or glycolic acid derivative is 1:(20-5000).

[0092] The synthesis method in the embodiment of the present invention can be carried out under solvent-free conditions. However, when the raw material used in the reaction process is solid glycolic acid, the use of a solvent to increase the solubility of the reaction system is beneficial to the reaction. Different organic solvents can be used for the synthesis reaction. When a solvent is used, a solvent that does not contain a large amount of water, alcohol, amine, or ester is used as much as possible to avoid competitive reactions and the production of by-products. For example, various alkanes, aromatic hydrocarbons, ethers, and chlorine-containing solvents can be used, specifically one or more selected from n-hexane, cyclohexane, tetrahydrofuran, diethyl ether, dioxane, toluene, trimethylbenzene, dichloromethane, dichloroethane, and carbon tetrachloride.

[0093] According to some preferred embodiments, the reaction temperature is -50 to 100°C (for example, -50°C, -10°C, 0°C, 10°C, 20°C, 30°C, 50°C, 80°C or 100°C), and the reaction time is 10-60 min (for example, 10 min, 20 min, 30 min, 40 min, 50 min or 60 min).

[0094] The synthesis method in the embodiment of the present invention has a wide temperature range. When no catalyst is added, the reaction can be promoted by increasing the temperature. When a catalyst is added, the reaction can be carried out at room temperature. The reaction process will spontaneously generate heat to accelerate the reaction. No heating or cooling device is required. The reaction can be completed within 10-30 minutes and a high conversion rate can be achieved, which greatly reduces energy consumption and equipment costs. When a catalyst is added, the reaction can also be carried out under heating conditions, thereby increasing the catalytic activity of the catalyst to catalyze the ring-opening reaction of ethylene oxide, and the reaction temperature is increased within a certain range. Without affecting the purity and yield of the product, it is beneficial to shorten the reaction time. However, the temperature of the reaction system should be controlled not to exceed the above-mentioned maximum problem. This can avoid the increase of side reaction products and the deactivation of the catalyst, thereby ensuring the yield and purity of the target product.

[0095] At the same time, the synthesis process in the embodiment of the present invention needs to be carried out under normal pressure and closed environment conditions, without the use of inert gas, avoiding the use of high-pressure reaction equipment and inert gas, and ensuring the safety of the synthesis process.

[0096] According to some other preferred embodiments, the catalyst is selected from one or more of anion exchange resin catalysts, ammonium salt catalysts, quaternary ammonium salt catalysts, polyquaternary ammonium salt catalysts, quaternary phosphonium salt catalysts or sulfonium salt catalysts.

[0097] Furthermore, experimental verification in the embodiments of the present invention found that the use of the above-mentioned types of organic catalysts to catalyze the reaction of glycolic acid or glycolic acid derivatives with ethylene oxide is beneficial to significantly increase the yield of pDO, and the yield of pDO can be as high as 90-99%, and the content of the catalyst used is even lower, thereby reducing the catalyst residue in the reaction system and reducing the difficulty of purification; at the same time, considering that quaternary ammonium salt catalysts and quaternary phosphonium salt catalysts are stable, low toxicity, easy to store and extremely low cost, quaternary ammonium salt and quaternary phosphonium salt catalysts are the preferred catalyst types in the reaction method for synthesizing pDO of the present invention.

[0098] According to some specific embodiments, the anion exchange resin catalyst is selected from one or more of a strongly basic ion exchange resin, a weakly basic ion exchange resin, a supported quaternary ammonium salt, or a supported quaternary phosphonium salt;

[0099] The ammonium salt catalyst is selected from one or more of ammonium fluoride, ammonium chloride, ammonium bromide or ammonium iodide;

[0100] The structural formula of the quaternary ammonium salt catalyst is as follows:

[0101] R is a C1-C 22 Alkyl, aromatic group with substituent or aromatic heterocyclic group with substituent; the substituent is C1-C 10 Alkyl, C1-C 10 Alkoxy or hydroxy, the heteroatom in the aromatic heterocyclic group is nitrogen, sulfur or oxygen; X is fluoride, chloride, bromide, iodide, acetate, sulfate, sulfite, bisulfate, nitrate, nitrite, carbonate, bicarbonate, sulfonate or p-toluenesulfonate;

[0102] The polyquaternium salt catalyst is selected from one or more of polydimethyldiallylammonium chloride, polyquaternium-10 or polyquaternium-55;

[0103] The structural formula of the quaternary phosphonium salt catalyst is as follows:

[0104] R is a C1-C 22 Alkyl, aromatic group with substituent or aromatic heterocyclic group with substituent; the substituent is C1-C 10 Alkyl, C1-C 10 The heteroatom in the aromatic heterocyclic group is nitrogen, sulfur or oxygen, and X is fluoride, chloride, bromide or iodide.

[0105] The sulfonium salt catalyst is selected from one or more of trimethylsulfonium bromide, trimethylsulfonium iodide, trimethylsulfonium tetrafluoroborate, triethylsulfonium iodide, triphenylsulfonium chloride, triphenylsulfonium bromide or triphenylsulfonium trifluoromethanesulfonate.

[0106] In the embodiment of the present invention, the quaternary ammonium salt catalyst can specifically be tetramethylammonium fluoride, tetramethylammonium fluoride tetrahydrate, tetramethylammonium chloride, tetramethylammonium acetate, tetramethylammonium borohydride, tetramethylammonium p-toluenesulfonate, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium fluoride, tetraethylammonium fluoride dihydrate, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, tetrapropylammonium fluoride, tetrapropylammonium chloride, tetrapropylammonium bromide, tetrapropylammonium iodide, tetrabutylammonium fluoride, tetrabutylammonium fluoride trihydrate, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium acetate, tetrabutylammonium sulfate, tetrabutylammonium p-toluenesulfonate, tetrabutylammonium fluoroborate, tetrabutylammonium sulfhydric acid, tetrabutylhexafluoro Ammonium phosphate, tetrapentylammonium fluoride, tetrapentylammonium chloride, tetrapentylammonium bromide, tetrapentylammonium iodide, tetrahexylammonium fluoride, tetrahexylammonium chloride, tetrahexylammonium bromide, tetrahexylammonium iodide, tetraheptylammonium fluoride, tetraheptylammonium chloride, tetraheptylammonium bromide, tetraheptylammonium iodide, tetraoctylammonium fluoride, tetraoctylammonium chloride, tetraoctylammonium bromide, tetraoctylammonium iodide, tetranonylammonium fluoride, tetranonylammonium chloride, tetranonylammonium bromide, tetranonylammonium iodide, tetradecylammonium fluoride, tetradecylammonium chloride, tetradecylammonium bromide, tetradecylammonium iodide, decanyltrimethylammonium fluoride, decanyltrimethylammonium chloride, decanyltrimethylammonium bromide, decanyltrimethylammonium iodide, undecyltrimethylammonium fluoride, undecyltrimethylammonium chloride, undecyltrimethylammonium bromide, undecyltrimethylammonium Methylammonium iodide, dodecyltrimethylammonium fluoride, dodecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, dodecyltrimethylammonium iodide, tridecyltrimethylammonium fluoride, tridecyltrimethylammonium chloride, tridecyltrimethylammonium bromide, tridecyltrimethylammonium iodide, tetradecyltrimethylammonium fluoride, tetradecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, tetradecyltrimethylammonium iodide, pentadecyltrimethylammonium fluoride, pentadecyltrimethylammonium chloride, pentadecyltrimethylammonium bromide, pentadecyltrimethylammonium iodide, hexadecyltrimethylammonium fluoride, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium iodide, octadecyltrimethylammonium fluoride, octadecyltrimethylammonium chloride, octadecyltrimethylammonium Alkyltrimethylammonium bromide, octadecyltrimethylammonium iodide, eicosyltrimethylammonium fluoride, eicosyltrimethylammonium chloride, eicosyltrimethylammonium bromide, eicosyltrimethylammonium iodide, docosyltrimethylammonium fluoride, docosyltrimethylammonium chloride, docosyltrimethylammonium bromide, docosyltrimethylammonium iodide, phenyltrimethylammonium fluoride, phenyltrimethylammonium chloride, phenyltrimethylammonium bromide, phenyltrimethylammonium iodide, benzyltrimethylammonium fluoride, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, benzyltrimethylammonium iodide, single-chain quaternary ammonium salt (dodecyldimethylbenzylammonium chloride), double-chain quaternary ammonium salt (diethyldimethylammonium chloride), double-chain quaternary ammonium salt (didecyldimethylammonium chloride), bis(triphenylphosphorane)ammonium chloride,One or more of pyridine halide, imidazolium bromide, 1-butyl-1-methylpyrrolidine bromide.

[0107] In the embodiments of the present invention, the above-mentioned type of organic catalyst was obtained through further extensive screening. Since the above-mentioned type of catalyst does not contain any metal, it is easy to remove and has very low toxicity. It is also inexpensive and can effectively reduce production costs. Furthermore, this type of catalyst is highly selective for the ring-opening position of ethylene oxide and has high catalytic activity for the hydroxyl groups in glycolic acid or glycolic acid derivatives to attack ethylene oxide. It can significantly accelerate the reaction rate of glycolic acid or glycolic acid derivatives with ethylene oxide, reduce the occurrence of side reactions, and ultimately improve the yield of the product.

[0108] According to some preferred embodiments, when the catalyst is selected from one or more of anion exchange resin catalysts, ammonium salt catalysts, quaternary ammonium salt catalysts, polyquaternary ammonium salt catalysts, quaternary phosphonium salt catalysts or sulfonium salt catalysts:

[0109] The molar ratio of the catalyst to glycolic acid or glycolic acid derivative is 1:(20-10000) (for example, 1:20, 1:50, 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900, 1:1000, 1:2000, 1:3000, 1:4000, 1:5000, 1:6000, 1:7000, 1:8000, 1:900 0 or 1:10000), more preferably 1:(20-5000); the molar ratio of ethylene oxide to glycolic acid or glycolic acid derivative is (1-10):(1-10) (for example, it can be 1:1, 1:2, 1:5, 1:8, 1:10, 5:1, 8:1, 10:1, 5:2, 5:5, 8:5 or 10:10), more preferably (1-2):(1-2) (for example, it can be 1:1, 1:2, 2:1 or 2:2).

[0110] According to some preferred embodiments, the reaction temperature is 25-100°C (for example, 25°C, 30°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C), and the reaction time is 10 min-6 h (for example, 10 min, 30 min, 1 h, 2 h, 3 h, 4 h, 5 h or 6 h).

[0111] In the embodiments of the present invention, during the reaction process, the catalyst, glycolic acid or glycolic acid derivative, and ethylene oxide contents are rationally controlled to maximize the reaction rate, suppress side reactions, and maintain the physical stability of the reaction system, thereby achieving efficient synthesis of 1,4-dioxane-2-one. Experiments in the present invention have confirmed that if the catalyst content is too low, the reaction rate will be reduced and the yield of the target product will decrease. If the catalyst content is too high, it will not only cause the self-polymerization of ethylene oxide but also increase the subsequent catalyst separation cost. At the same time, the molar ratio of glycolic acid or glycolic acid derivative to ethylene oxide is preferably between 2:1 and 1:2, which can promote the reaction to a certain extent. Excess raw materials can be recovered by distillation or other methods. Furthermore, when the molar ratio of glycolic acid or glycolic acid derivative to ethylene oxide is selected at 1:1, glycolic acid or glycolic acid derivative and ethylene oxide can be completely converted, and both raw materials can be utilized 100%. In this way, the product does not contain any raw materials, reducing the difficulty of purification and improving product purity.

[0112] In some preferred embodiments, the catalyst is selected from one or more of an organic base catalyst, an ionic liquid catalyst, an anion exchange resin catalyst, an ammonium salt catalyst, a quaternary ammonium salt catalyst, a polyquaternary ammonium salt catalyst, a quaternary phosphonium salt catalyst or a sulfonium salt catalyst.

[0113] In the embodiments of the present invention, experimental verification found that when the above-mentioned types of catalysts are used, the above-mentioned types of catalysts can synergistically activate multiple reaction molecules simultaneously through multiple mechanisms, thereby accelerating the cascade steps of ring opening and cyclization of ethylene oxide with glycolic acid or glycolic acid derivatives, and reducing the occurrence of side reactions (such as ethylene oxide self-polymerization or intermolecular esterification). In this way, while ensuring the efficient progress of the reaction, the selectivity of the target product is precisely controlled, and ultimately a high-yield and high-purity synthesis of 1,4-dioxane-2-one is achieved.

[0114] It should be noted that when the catalyst is a series of solid catalysts such as ion exchange resins, molecular sieves, and supported catalysts, a solid-liquid heterogeneous reaction can be carried out in the reaction device. After the reaction is completed, the solid catalyst can be recovered by filtration or centrifugation, and can be used again for catalytic synthesis after washing and activation.

[0115] According to some preferred embodiments, after the reaction is completed, the steps of filtering, washing, distilling and crystallizing the crude product obtained by the reaction are further included.

[0116] In an embodiment of the present invention, after the reaction is completed, the above method can be used to separate and purify the crude product obtained by the reaction, thereby facilitating the acquisition of high-purity 1,4-dioxane-2-one; wherein, the specific process parameters of filtration, washing, distillation, and crystallization can be adjusted according to actual needs.

[0117] According to some preferred embodiments, after adding the catalyst to the reaction system, the step of adding an organic solvent to the reaction system is further included: wherein the organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, tetrahydrofuran, dioxane, dichloroethane, chloroform, carbon tetrachloride, toluene, xylene, and trimethylbenzene.

[0118] In an embodiment of the present invention, further, by selecting a certain type of organic solvent to match the catalyst, preferably, the volume ratio of ethylene oxide to the organic solvent is (1-1): (1-10), so that side reactions can be further directionally suppressed, and the polarity of the organic solvent and the catalyst is matched, thereby maximizing the catalyst activity, thereby ensuring that the synthesis of 1,4-dioxane-2-one achieves an optimal balance between high selectivity, high yield, high purity, operability and safety.

[0119] The present invention also provides high-purity 1,4-dioxane-2-one, which is prepared by the low-cost preparation method provided by the present invention.

[0120] In an embodiment of the present invention, 1,4-dioxane-2-one is synthesized in a one-step process using bulk products such as ethylene oxide, glycolic acid, or glycolic acid derivatives as reaction raw materials. By rationally controlling the types and proportions of the raw materials during the reaction, the reaction produces fewer byproducts, resulting in a final yield significantly higher than that of the prior art (>70%). Energy consumption and production costs are also greatly reduced, and the raw materials are widely available, avoiding the problem of being restricted by raw material sources. Furthermore, using inexpensive and readily available organic chemicals as efficient catalysts, high-purity 1,4-dioxane-2-one without metal residues can be synthesized, and the yield can be further increased to 90-99%. Finally, the product is purified by distillation, crystallization, or sublimation, further ensuring the high purity and high yield of the product. The yield of 1,4-dioxane-2-one is 30-99%, and the purity exceeds 99.5%. The process conditions of the present invention are suitable for large-scale product purification and actual industrial production.

[0121] In order to more clearly illustrate the technical solution and advantages of the present invention, a method for preparing high-purity 1,4-dioxane-2-one at low cost is described in detail below through several examples.

[0122] Example 1:

[0123] Under air, 103 g of glycolic acid (1.35 mol), 150 mL of a tetrahydrofuran solution of ethylene oxide (3 mol / L, 0.45 mol ethylene oxide), and 100 mL of tetrahydrofuran were added to a reaction flask. The mixture was stirred at 60°C for 30 minutes. After completion of the reaction, the tetrahydrofuran was distilled off at 60°C. The product was dissolved in dichloromethane, and the excess glycolic acid was removed by filtration. The residual glycolic acid was then washed twice with saturated sodium bicarbonate solution to remove it. After completion, 1,4-dioxane-2-one was obtained by vacuum distillation at 90-100°C. The yield was calculated by weight to be 43.7%, and the purity was ~98% as measured by HPLC and H-NMR spectroscopy.

[0124] Example 2:

[0125] Under air atmosphere, 103 g of glycolic acid (1.35 mol), 150 mL of a tetrahydrofuran solution of ethylene oxide (3 mol / L, 0.45 mol of ethylene oxide), and 100 mL of tetrahydrofuran were added to a reaction flask. 0.72 mL of a catalyst (concentrated sulfuric acid (0.04 mol)) was added, and the mixture was stirred at room temperature (25°C) for 30 minutes. After the reaction was completed, the tetrahydrofuran was evaporated; the product was dissolved in dichloromethane, the excess glycolic acid was filtered out, and the residual glycolic acid was washed twice with a saturated aqueous sodium bicarbonate solution to remove the residual glycolic acid. After completion, 1,4-dioxane-2-one was obtained by reduced pressure distillation at 90-100°C in a yield of 55.6% and a purity of ∼99%.

[0126] Example 3

[0127] Under air, a reaction flask was charged with 103 g of glycolic acid (1.35 mol), 450 mL of a tetrahydrofuran solution of ethylene oxide (3 mol / L, 1.35 mol ethylene oxide), and 100 mL of tetrahydrofuran. 0.72 mL of a catalyst (concentrated sulfuric acid (0.04 mol)) was added and stirred at room temperature for 30 minutes. After completion of the reaction, the tetrahydrofuran was evaporated. The product was dissolved in dichloromethane, and the excess glycolic acid was filtered to remove it. The residual glycolic acid was washed twice with saturated sodium bicarbonate aqueous solution to remove it. After completion, 1,4-dioxane-2-one was obtained by vacuum distillation at 90-100°C in a yield of 40.0% and a purity of 99%.

[0128] Example 4

[0129] Under air, add 103 g of glycolic acid (1.35 mol) and 22.5 mL of ethylene oxide (0.45 mol) to a reaction flask and stir at 60°C for 30 minutes. Dissolve the product in dichloromethane, filter to remove excess glycolic acid, and wash twice with saturated sodium bicarbonate solution to remove residual glycolic acid. After completion, distill under reduced pressure at 90-100°C to obtain 1,4-dioxane-2-one in a yield of 60.1% and a purity of ~95%.

[0130] Example 5

[0131] Under air, add 103 g of glycolic acid (1.35 mol) and 67 mL of ethylene oxide (1.35 mol) to a reaction flask and stir at 60°C for 30 minutes. Dissolve the product in dichloromethane, filter to remove excess glycolic acid, and wash twice with saturated sodium bicarbonate solution to remove residual glycolic acid. After completion, distill under reduced pressure at 90-100°C to obtain 1,4-dioxane-2-one in a yield of 52.5% and a purity of ~97%.

[0132] Example 6

[0133] Under air atmosphere, 174 mL of methyl glycolate (2.25 mol) and 150 mL of a tetrahydrofuran solution of ethylene oxide (3 mol / L, 0.45 mol ethylene oxide) were added to a reaction flask, followed by 1.2 mL of concentrated sulfuric acid (22.5 mmol). The mixture was stirred at room temperature for 10 minutes. After the reaction was completed, the tetrahydrofuran was evaporated, and the methyl glycolate was recovered by vacuum distillation at 50-60°C. After completion, the temperature was raised to 90-100°C and vacuum distilled to obtain 1,4-dioxane-2-one with a yield of 69.7% and a purity of >99%.

[0134] Example 7

[0135] Under air atmosphere, 174 mL of methyl glycolate (2.25 mol) and 450 mL of a tetrahydrofuran solution of ethylene oxide (3 mol / L, 1.35 mol ethylene oxide) were added to a reaction flask, followed by 1.2 mL of concentrated sulfuric acid (22.5 mmol). The mixture was stirred at room temperature for 10 minutes. After the reaction was completed, the tetrahydrofuran was evaporated, and then the methyl glycolate was distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 62% and a purity of >99%.

[0136] Example 8

[0137] Under air atmosphere, 174 mL of methyl glycolate (2.25 mol) and 22.5 mL of ethylene oxide (0.45 mol) were added to the reaction flask, and 1.2 mL of concentrated sulfuric acid (22.5 mmol) was added. The mixture was stirred at room temperature for 10 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60 ° C. After completion, the temperature was raised to 90-100 ° C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 76% and a purity of >99%.

[0138] Example 9

[0139] Under air atmosphere, 174 mL of methyl glycolate (2.25 mol) and 11.5 mL of ethylene oxide (0.23 mol) were added to the reaction flask, and 0.6 mL of concentrated sulfuric acid (11.3 mmol) was added. The mixture was stirred at room temperature for 10 minutes. After the reaction was completed, tetrahydrofuran was evaporated, and then the methyl glycolate was recovered by vacuum distillation at 50-60° C. After completion, the temperature was raised to 90-100° C. and vacuum distillation was performed to obtain 1,4-dioxane-2-one with a yield of 99% and a purity of >99%.

[0140] Example 10

[0141] Under air atmosphere, 174 mL of methyl glycolate (2.25 mol) and 22.5 mL of ethylene oxide (0.45 mol) were added to the reaction flask, and 100 μL of catalyst (boron trifluoride ether solution (46.5% BF3) 0.446 mmol) was added. The mixture was stirred at room temperature for 10 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 83% and a purity of >99%.

[0142] Example 11

[0143] Under air atmosphere, 174 mL of methyl glycolate (2.25 mol) and 11.5 mL of ethylene oxide (0.23 mol) were added to the reaction flask, and 50 μL of catalyst (boron trifluoride ether solution (46.5% BF3) 0.446 mmol) was added. The mixture was stirred at 0°C for 30 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 95% and a purity of >99%.

[0144] pass Figure 1 The H-NMR spectrum test attributed all chemical shift signals, and the integrated area ratio of the three groups of peaks was 2:2:2, corresponding to the three methylene structures respectively; Figure 2 1750cm in Fourier infrared test -1 and 1200cm -1 The left and right signals correspond to the stretching vibrations of the ester and ether bonds of pDO, respectively, proving the structures of the ester and ether bonds; Figure 3 This shows that pDO is in solid state at room temperature and has a melting point of around 32°C, providing a temperature reference for melt polymerization. The above results prove that the product is indeed a pDO structure.

[0145] Example 12

[0146] Under air atmosphere, 174 mL of methyl glycolate (2.25 mol) and 22.5 mL of ethylene oxide (0.45 mol) were added to the reaction flask, and 3.6 g of catalyst (ferric chloride (22.5 mmol)) was added. The mixture was stirred at room temperature for 10 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60 ° C. After completion, the temperature was raised to 90-100 ° C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 81% and a purity of >99%.

[0147] Example 13

[0148] Under air atmosphere, 174 mL of methyl glycolate (2.25 mol) and 11.5 mL of ethylene oxide (0.23 mol) were added to the reaction flask, and 1.8 g of catalyst (ferric chloride (11.3 mmol)) was added. The mixture was stirred at room temperature for 10 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60 ° C. After completion, the temperature was raised to 90-100 ° C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 81% and a purity of >99%.

[0149] Example 14

[0150] Under air atmosphere, 174 mL of methyl glycolate (2.25 mol) and 22.5 mL of ethylene oxide (0.45 mol) were added to the reaction flask, and 3.9 g of catalyst (p-toluenesulfonic acid (22.5 mmol)) was added. The mixture was stirred at 0°C for 10 minutes and at room temperature for 10 minutes. The methyl glycolate was then distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 98% and a purity of >99%.

[0151] Example 15

[0152] Under air atmosphere, 174 mL of methyl glycolate (2.25 mol) and 112 mL of ethylene oxide (2.25 mol) were added to the reaction flask, and 3.6 g of catalyst (ferric chloride (22.5 mmol)) was added. The mixture was stirred at room temperature for 10 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60 ° C. After completion, the temperature was raised to 90-100 ° C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 41% and a purity of >99%.

[0153] Example 16

[0154] Under air atmosphere, 174 mL of methyl glycolate (2.25 mol) and 112 mL of ethylene oxide (2.25 mol) were added to the reaction flask, and 100 μL of catalyst (boron trifluoride ether solution (46.5% BF3)) was added. The mixture was stirred at room temperature for 10 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 23% and a purity of ~97%.

[0155] Example 17

[0156] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask, and 0.44 mL of catalyst (trifluoromethanesulfonic acid (5 mmol)) was added. The mixture was stirred at room temperature for 5 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60 ° C. After completion, the temperature was raised to 90-100 ° C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 59% and a purity of >99%.

[0157] Example 18

[0158] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask, and 2.6 g of catalyst (tris(pentafluorophenyl)boron (5 mmol)) was added. The mixture was stirred at room temperature for 5 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60 ° C. After completion, the temperature was raised to 90-100 ° C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 73% and a purity of >99%.

[0159] Example 19

[0160] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask, and 0.5 g of catalyst (sodium carbonate (5 mmol)) was added. The mixture was stirred at 50°C for 30 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 18% and a purity of >99%.

[0161] Example 20

[0162] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask, and 0.8 g of catalyst (1,8-diazabicyclo[5.4.0]undec-7-ene (5 mmol)) was added. The mixture was stirred at 50°C for 30 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 28% and a purity of >99%.

[0163] Example 21

[0164] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask, and 2.4 g of catalyst (aluminum trifluoromethanesulfonate (5 mmol)) was added. The mixture was stirred at 0°C for 30 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 48% and a purity of >99%.

[0165] Example 22

[0166] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask, and 1.3 g of catalyst (copper tetrafluoroborate (5 mmol)) was added. The mixture was stirred at 0°C for 30 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 71% and a purity of >99%.

[0167] Example 23

[0168] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask, and 1.1 g of catalyst (indium trichloride (5 mmol)) was added. The mixture was stirred at 50°C for 180 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 62% and a purity of >99%.

[0169] Example 24

[0170] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask, and 0.9 g of catalyst (antimony trifluoride (5 mmol)) was added. The mixture was stirred at room temperature for 30 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60 ° C. After completion, the temperature was raised to 90-100 ° C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 43% and a purity of >99%.

[0171] Example 25

[0172] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask, and 1.8 g of catalyst (zirconium sulfate tetrahydrate (5 mmol)) was added. The mixture was stirred at 50°C for 30 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 53% and a purity of >99%.

[0173] Example 26

[0174] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask, and 2.0 g of catalyst (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide) (5 mmol) was added. The mixture was stirred at room temperature for 10 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 45% and a purity of >99%.

[0175] Example 27

[0176] Under air atmosphere, 0.7 mL of triethylamine (5 mmol) and 0.86 g of p-toluenesulfonic acid (5 mmol) were mixed in a flask to prepare a Lewis acid-base catalyst. Then, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask. The mixture was stirred at room temperature for 10 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60°C. After completion, the temperature was raised to 90-100°C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 44% and a purity of >99%.

[0177] Example 28

[0178] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to a reaction flask, and 5 g of catalyst (strongly acidic cation exchange resin Amberlyst-150.023 mol sulfonic acid group) was added. The mixture was stirred at 100° C. for 30 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60° C. After completion, the temperature was raised to 90-100° C. and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 59% and a purity of >99%.

[0179] Example 29

[0180] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask, and 5 g of catalyst (0.006 mol acid sites of β-type molecular sieve) was added. The mixture was stirred at 100 ° C for 30 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60 ° C. After completion, the temperature was raised to 90-100 ° C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 43% and a purity of >99%.

[0181] Example 30

[0182] Under air atmosphere, 77 mL of methyl glycolate (1.0 mol) and 9.8 mL of ethylene oxide (0.2 mol) were added to the reaction flask, and 10 g of catalyst (0.007 mol acid sites of ZSM-5 molecular sieve) was added. The mixture was stirred at 100 ° C for 30 minutes, and then the methyl glycolate was distilled under reduced pressure at 50-60 ° C. After completion, the temperature was raised to 90-100 ° C and distilled under reduced pressure to obtain 1,4-dioxane-2-one with a yield of 63% and a purity of >99%.

[0183] Example 31

[0184] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 2.3 g of bis(triphenylphosphorane)ammonium chloride (0.004 mol) were added to the reaction flask and stirred at 70°C for 24 hours. After the reaction was completed, the temperature was returned to room temperature (25°C). The unreacted raw materials were collected by vacuum distillation at 50-60°C, and finally 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 95% and the purity was >99%.

[0185] Example 32

[0186] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 2.3 g of catalyst (bis(triphenylphosphorane)ammonium chloride (0.004 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 99% and the purity was >99%.

[0187] pass Figure 4 It can be found from the H NMR spectrum test diagram in the embodiment that all chemical shift signals are attributed to the H NMR spectrum, and the integrated area ratio of the three groups of peaks is 2:2:2, corresponding to three methylene structures respectively, thereby confirming that the synthesized product is 1,4-dioxane-2-one.

[0188] Example 33

[0189] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 2.3 g of catalyst (bis(triphenylphosphorane)ammonium chloride (0.004 mol)) were added to the reaction flask and stirred at 70°C for 1 hour. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 75% and the purity was >99%.

[0190] Example 34

[0191] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 15 mL of ethylene oxide (0.3 mol) and 2.3 g of catalyst (bis(triphenylphosphorane)ammonium chloride (0.004 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 83% and the purity was >99%.

[0192] Example 35

[0193] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 10 mL of ethylene oxide (0.2 mol) and 2.3 g of catalyst (bis(triphenylphosphorane)ammonium chloride (0.004 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 90% and the purity was >99%.

[0194] Example 36

[0195] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 1.1 g of catalyst (tetrabutylammonium chloride (0.004 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 98% and the purity was >99%.

[0196] Example 37

[0197] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 10 mL of ethylene oxide (0.2 mol) and 1.1 g of catalyst (tetrabutylammonium chloride (0.004 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 72% and the purity was >99%.

[0198] Example 38

[0199] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 0.79 g of catalyst (polyquaternium salt (0.004 mol)) were added to the reaction flask and stirred at 70 ° C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60 ° C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100 ° C. The calculated yield was 85% and the purity was >99%.

[0200] Example 39

[0201] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 0.4 g of catalyst (triethylamine (0.004 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 96% and the purity was >99%.

[0202] Example 40

[0203] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 0.16 g of catalyst (sodium hydroxide (0.004 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 96% and the purity was 95%.

[0204] Example 41

[0205] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 0.56 g of catalyst (1,5,7-triazabicyclo[4.4.0]dec-5-ene (0.004 mol)) were added to the reaction flask and stirred at 50°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 88% and the purity was 90%.

[0206] Example 42

[0207] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 0.40 g of catalyst (triethylamine (0.004 mol)) were added to the reaction flask and stirred at 50°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 91% and the purity was 95%.

[0208] Example 43

[0209] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 0.49 g of catalyst (4-dimethylaminopyridine (0.004 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 96% and the purity was >99%.

[0210] Example 44

[0211] Under air atmosphere, 14 g of glycolic acid (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 2.3 g of catalyst (bis(triphenylphosphorane)ammonium chloride (0.004 mol)) were added to the reaction flask and stirred at 70°C for 12 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 83% and the purity was >99%.

[0212] Example 45

[0213] Under air atmosphere, 14 g of glycolic acid (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 1.1 g of catalyst (tetrabutylammonium chloride (0.004 mol)) were added to the reaction flask and stirred at 70°C for 12 hours. After the reaction was completed, the temperature was returned to room temperature. Unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 75% and the purity was >99%.

[0214] Example 46

[0215] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 0.22 g of catalyst (tetrabutylammonium chloride (0.0008 mol)) were added to the reaction flask and stirred at 70°C for 12 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 75% and the purity was >99%.

[0216] Example 47

[0217] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 0.11 g of catalyst (tetrabutylammonium chloride (0.0004 mol)) were added to the reaction flask and stirred at 70°C for 12 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 71% and the purity was >99%.

[0218] Example 48

[0219] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 55.5 mg of catalyst (tetrabutylammonium chloride (0.2 mmol)) were added to the reaction flask and stirred at 70°C for 12 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 65% and the purity was >99%.

[0220] Example 49

[0221] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 0.11 g of catalyst (tetrabutylammonium chloride (0.4 mmol)) were added to the reaction flask and stirred at 70°C for 12 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 57% and the purity was >99%.

[0222] Example 50

[0223] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 20 mL of ethylene oxide (0.4 mol) and 5.55 mg of catalyst (tetrabutylammonium chloride (0.02 mmol)) were added to the reaction flask and stirred at 70°C for 12 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 48% and the purity was >99%.

[0224] Example 51

[0225] Under air atmosphere, 7.7 mL of methyl glycolate (0.1 mol), 6.4 mL of ethylene oxide (0.125 mol) and 0.6 g of catalyst (tetrabutyl acetamide (0.002 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 80% and the purity was >99%.

[0226] Example 52

[0227] Under air atmosphere, 7.7 mL of methyl glycolate (0.1 mol), 6.4 mL of ethylene oxide (0.125 mol) and 0.33 g of catalyst (tetraethylammonium chloride (0.002 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 84% ​​and the purity was >99%.

[0228] Example 53

[0229] Under air atmosphere, 7.7 mL of methyl glycolate (0.1 mol), 6.4 mL of ethylene oxide (0.125 mol) and 0.83 g of catalyst (tetrabutylammonium p-toluenesulfonate (0.002 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 87% and the purity was >99%.

[0230] Example 54

[0231] Under air atmosphere, 7.7 mL of methyl glycolate (0.1 mol), 6.4 mL of ethylene oxide (0.125 mol) and 0.64 g of catalyst (hexadecyltrimethylammonium chloride (0.002 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 91% and the purity was >99%.

[0232] Example 55

[0233] Under air atmosphere, 7.7 mL of methyl glycolate (0.1 mol), 6.4 mL of ethylene oxide (0.125 mol) and 0.59 g of a quaternary phosphonium salt catalyst (tetraethylphosphine chloride (0.002 mol)) were added to a reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. Unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 77% and the purity was >99%.

[0234] Example 56

[0235] Under air atmosphere, 7.7 mL of methyl glycolate (0.1 mol), 6.4 mL of ethylene oxide (0.125 mol) and 0.42 g of an organic base catalyst (diphenylguanidine (0.002 mol)) were added to a reaction flask and stirred at 70°C for 6 hours. After completion of the reaction, the temperature was returned to room temperature. Unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 68% and the purity was >99%.

[0236] Example 57

[0237] Under air atmosphere, 7.7 mL of methyl glycolate (0.1 mol), 6.4 mL of ethylene oxide (0.125 mol) and 0.34 g of imidazole ionic liquid catalyst (1-ethyl-3-methylimidazolium acetate (0.002 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C, and finally 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 92% and the purity was >99%.

[0238] Example 58

[0239] Under air atmosphere, 7.7 mL of methyl glycolate (0.1 mol), 6.4 mL of ethylene oxide (0.125 mol) and 0.46 g of imidazole ionic liquid catalyst (1-methyl-3-octylimidazolium chloride (0.002 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C, and finally 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 83% and the purity was >99%.

[0240] Example 59

[0241] Under air atmosphere, 7.7 mL of methyl glycolate (0.1 mol), 6.4 mL of ethylene oxide (0.125 mol) and 0.52 g of imidazole ionic liquid catalyst (1-decyl-3-methylimidazolium chloride (0.002 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C, and finally 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 90% and the purity was >99%.

[0242] Example 60

[0243] Under air atmosphere, 7.7 mL of methyl glycolate (0.1 mol), 6.4 mL of ethylene oxide (0.125 mol) and 0.60 g of sulfonium salt catalyst (triphenylsulfonium chloride (0.002 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 93% and the purity was >99%.

[0244] Example 61

[0245] Under air atmosphere, 7.7 mL of methyl glycolate (0.1 mol), 6.4 mL of ethylene oxide (0.125 mol) and 0.47 g of phosphazene base catalyst (phosphazene base P1-t-Bu (0.002 mol)) were added to the reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C. Finally, 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 83% and the purity was >95%.

[0246] Example 62

[0247] Under air atmosphere, 15.4 mL of methyl glycolate (0.2 mol), 15 mL of ethylene oxide (0.3 mol), 20 mL of organic solvent (xylene) and 2.3 g of catalyst (bis(triphenylphosphorane)ammonium chloride (0.004 mol)) were added to a reaction flask and stirred at 70°C for 6 hours. After the reaction was completed, the temperature was returned to room temperature. The unreacted raw materials were collected by vacuum distillation at 50-60°C, and finally 1,4-dioxane-2-one was collected by vacuum distillation at 90-100°C. The calculated yield was 88% and the purity was >99%.

[0248] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing high-purity 1,4-dioxane-2-one at low cost, characterized in that: The method comprises: mixing ethylene oxide with glycolic acid or a glycolic acid derivative, and obtaining the high-purity 1,4-dioxane-2-one after reaction; wherein the glycolic acid derivative comprises glycolate or glycolate ester, and the structural formula of the glycolate ester is as follows: In the formula, R is a C1-C8 alkyl group, a C3-C8 cycloalkyl group, an aromatic group or an aromatic heterocyclic group having a substituent, and the substituent is a halogen, a C1-C3 alkyl group, a halogenated C1-C3 alkyl group, a C1-C3 alkoxy group or a hydroxyl group.

2. The method according to claim 1, characterized in that Before the reaction is carried out, the step of adding a catalyst to the reaction system is also included; wherein the catalyst is selected from an inorganic acid catalyst, an organic acid catalyst, an inorganic base catalyst, an organic base catalyst, a metal chloride catalyst, a metal oxide catalyst, a metal salt catalyst, an ionic liquid catalyst, a solid acid catalyst, a Lewis acid-base pair catalyst, a cation exchange resin catalyst or a molecular sieve catalyst; and / or The molar ratio of the catalyst to glycolic acid or glycolic acid derivative is 1:(20-10000).

3. The method according to claim 2, wherein: The glycolate is selected from one or more of lithium glycolate, sodium glycolate, potassium glycolate, calcium glycolate, magnesium glycolate, aluminum glycolate or ferric glycolate; and / or The glycolate ester is selected from one or more of methyl glycolate, ethyl glycolate, n-propyl glycolate, isopropyl glycolate, n-butyl glycolate, isobutyl glycolate, tert-butyl glycolate, phenyl glycolate or benzyl glycolate.

4. The method according to claim 2, wherein: The molar ratio of ethylene oxide to glycolic acid or glycolic acid derivative is (1-10): (1-10); Preferably, the molar ratio of ethylene oxide to glycolic acid or glycolic acid derivatives is 1:(1-5).

5. The method according to claim 2, wherein: The inorganic acid catalyst is selected from one or more of sulfuric acid, hydrochloric acid, hydrobromic acid, tungstic acid, titanic acid, and boric acid; The organic acid catalyst is selected from one or more of methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, boron trifluoride, boron trifluoride ethyl ether, tris(pentafluorophenyl)boron, triethylboron, camphorsulfonic acid, benzoic acid, salicylic acid, oxalic acid, and malic acid; The inorganic base catalyst is selected from one or more of sodium carbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, lithium hydroxide, magnesium hydroxide, zinc hydroxide, copper hydroxide, iron hydroxide, and ammonium hydroxide; The organic base catalyst is selected from one or more of triethylamine, pyridine, 4-dimethylaminopyridine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and hexamethyldisilazane; The metal chloride catalyst is selected from one or more of ferric chloride, ferric dichloride, zinc dichloride, tin chloride, magnesium chloride, titanium chloride, aluminum chloride, and indium chloride; The metal oxide catalyst is selected from one or more of iron oxide, ferroferric oxide, copper oxide, magnesium oxide, zinc oxide, aluminum oxide, calcium oxide, and titanium oxide; The metal salt catalyst is selected from one or more of copper tetrafluoroborate, bismuth trifluoride, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, calcium carbonate, cesium carbonate, sodium glycolate, sodium acetate, lithium diisopropylamide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium tert-butoxide, n-butyl lithium, and isobutyl lithium; The ionic liquid catalyst is selected from one or more of imidazole ionic liquids, pyridine ionic liquids, quaternary ammonium salt ionic liquids, and quaternary phosphonium salt ionic liquids; The Lewis acid-base catalyst is obtained by mixing a Lewis acid and a Lewis base; wherein the Lewis acid is selected from one or more of methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, boron trifluoride, boron trifluoride ethyl ether, tris(pentafluorophenyl)boron, triethylboron, camphorsulfonic acid, benzoic acid, ferric chloride, ferric dichloride, zinc dichloride, tin chloride, magnesium chloride, titanium chloride, aluminum chloride, indium chloride, and diethylzinc; and the Lewis base is selected from one or more of triethylamine, ammonia monohydrate, pyridine, 4-dimethylaminopyridine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, hexamethyldisilazane, and carbene; The cation exchange resin is selected from one or more of a strongly acidic styrene-based cation exchange resin, a weakly acidic styrene-propylene-based cation exchange resin, a styrene divinylbenzene resin, and an acrylic acid-based cation exchange resin; The molecular sieve catalyst is selected from one or more of zirconium sulfate molecular sieve, beta molecular sieve, LaY molecular sieve, TS-1 molecular sieve, USY molecular sieve, and ZSM-5 molecular sieve; Preferably, the catalyst is selected from an inorganic acid catalyst, an organic acid catalyst, a metal chloride catalyst, a metal oxide catalyst, a metal salt catalyst, a solid acid catalyst or a Lewis acid-base pair catalyst.

6. The method according to claim 1, wherein: The reaction temperature is -50 to 100°C and the reaction time is 10 to 60 minutes; Preferably, after the reaction is completed, the process further comprises filtering, washing, distilling and crystallizing the crude product obtained from the reaction.

7. The method according to claim 2, characterized in that The catalyst is selected from one or more of anion exchange resin catalyst, ammonium salt catalyst, quaternary ammonium salt catalyst, polyquaternary ammonium salt catalyst, sulfonium salt catalyst or quaternary phosphonium salt catalyst; Preferably, the anion exchange resin catalyst is selected from one or more of a strongly basic ion exchange resin, a weakly basic ion exchange resin, a supported quaternary ammonium salt or a supported quaternary phosphonium salt; The ammonium salt catalyst is selected from one or more of ammonium fluoride, ammonium chloride, ammonium bromide or ammonium iodide; The structural formula of the quaternary ammonium salt catalyst is as follows: R is a C1-C 22 Alkyl, aromatic group with substituent or aromatic heterocyclic group with substituent; the substituent is C1-C 10 Alkyl, C1-C 10 Alkoxy or hydroxy, the heteroatom in the aromatic heterocyclic group is nitrogen, sulfur or oxygen; X is fluoride, chloride, bromide, iodide, acetate, sulfate, sulfite, bisulfate, nitrate, nitrite, carbonate, bicarbonate, sulfonate or p-toluenesulfonate; The polyquaternium salt catalyst is selected from one or more of polydimethyldiallylammonium chloride, polyquaternium-10 or polyquaternium-55; The structural formula of the quaternary phosphonium salt catalyst is as follows: R is a C1-C 22 Alkyl, aromatic group with substituent or aromatic heterocyclic group with substituent; the substituent is C1-C 10 Alkyl, C1-C 10 Alkoxy or hydroxy, the heteroatom in the aromatic heterocyclic group is nitrogen, sulfur or oxygen, and X is fluoride ion, chloride ion, bromide ion or iodide ion; The sulfonium salt catalyst is selected from one or more of trimethylsulfonium bromide, trimethylsulfonium iodide, trimethylsulfonium tetrafluoroborate, triethylsulfonium iodide, triphenylsulfonium chloride, triphenylsulfonium bromide or triphenylsulfonium trifluoromethanesulfonate.

8. The method according to claim 7, characterized in that The molar ratio of the catalyst to glycolic acid or glycolic acid derivative is 1:(20-10000); Preferably, the molar ratio of ethylene oxide to glycolic acid or glycolic acid derivative is (1 to 10) ： (1 ～ 10); More preferably, the reaction temperature is 25-100° C. and the reaction time is 10 min-6 h.

9. The method according to claim 2, characterized in that After adding the catalyst to the reaction system, the process further includes adding an organic solvent to the reaction system: wherein the organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, tetrahydrofuran, dioxane, dichloroethane, chloroform, carbon tetrachloride, toluene, xylene, and trimethylbenzene.

10. A high-purity 1,4-dioxane-2-one, characterized by: The method according to any one of claims 1 to 9 is used to prepare the present invention.

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