Method for separating liquid mixture containing diol compound

Abstract

The invention discloses a method for separating a liquid mixture containing a diol compound, which is characterized by comprising the following steps of: a, mixing a liquid product containing the diol compound with an extracting agent, and extracting to obtain a heavy phase and a light phase; and b, distilling the heavy phase obtained in the step a to obtain a diol compound, wherein the extraction agent comprises a first component and a second component, the solubility of the first component in water is not less than 1g / 100g, the solubility of the second component in water is not less than 0.5 g / 100g, the solubility of the first component in a mixture of the second component and water is not greater than 1g / 100g, and the solubility of the second component in a mixture of the first component and water is not greater than 1g / 100g. The method is simple, efficient, convenient to operate, low in energy consumption, high in yield and purity of the diol compound and suitable for large-scale production.

Description

A method for separating liquid mixtures containing diol compounds Technical Field

[0001] This invention relates to a method for separating compounds, and more specifically to a method for separating diol compounds from a liquid mixture containing diol compounds by extraction and distillation. Background Technology

[0002] Diols are compounds with at least two hydroxyl groups on their carbon chains. The presence of these hydroxyl groups gives diols a certain degree of water solubility, allowing them to be used as monomers in polymerization, in the production of antifreeze, de-icing agents, pharmaceuticals, and cosmetics. They are widely used and are important organic chemical intermediates. Common diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and 1,2-hexanediol. Diols are typically obtained through several pathways: ring-opening reactions of epoxide hydrolysis, olefin oxidation and hydration reactions, fermentation, and biomass reactions. The reaction products of diols usually contain a large amount of water, and compounds with multiple hydroxyl groups typically have high boiling points. To separate the water to obtain the diol product, vacuum multi-effect distillation is required, which is energy-intensive and results in product loss.

[0003] CN108779053 A discloses a method for producing propylene glycol from propylene and hydrogen peroxide, wherein the resulting aqueous solution containing propylene glycol is obtained by multi-stage separation to produce the propylene glycol product.

[0004] The literature (ACS Sustainable Chem. Eng. 2022, 10, 36, 11891–11901) proposed a three-component extractant consisting of octanol, undecylol and tetradecylol for the extraction of 1,3-propanediol products, but the recovery rate of this extractant system was low.

[0005] To date, there is no efficient and energy-saving separation method for aqueous solutions of glycols. Summary of the Invention

[0006] The purpose of this invention is to provide a method for the extraction and separation of diol products. This method has a simple process flow, is easy to operate, allows for easy separation of extractant components, has low energy consumption, and produces high diol yield and purity, making it suitable for large-scale production.

[0007] To achieve the above objectives, the present invention provides a method for separating a liquid mixture containing a diol compound, characterized in that the method comprises: step a: mixing a liquid product containing a diol with an extractant and then extracting it to obtain a heavy phase and a light phase; and step b: distilling the heavy phase obtained in step a to obtain the diol; wherein the extractant comprises a first component and a second component, the first component having a solubility in water of not less than 1 g / 100 g, the second component having a solubility in water of not less than 0.5 g / 100 g, the first component having a solubility in a mixture of the second component and water of not more than 1 g / 100 g, and the second component having a solubility in a mixture of the first component and water of not more than 1 g / 100 g.

[0008] Preferably, the first component is a haloalcohol and the second component is an epoxy compound.

[0009] Preferably, the haloalcohol of the first component has m carbon atoms, where m is preferably a positive integer from 1 to 12, and the halogen element, hydroxyl group and hydrogen are bonded to the carbon atoms. The halogen element can be one or more of fluorine, chlorine, bromine and iodine, and its number does not exceed 2m+1. The number of hydroxyl groups does not exceed 5. The epoxy compound of the second component preferably has n carbon atoms, where n is preferably a positive integer from 2 to 6, and contains at least one epoxy bond.

[0010] Preferably, the halogen element of the haloalcohol is fluorine.

[0011] Preferably, the haloalcohol may be 2,2,3,3-tetrafluoropropanol (76-37-9), 1H,1H-pentafluoropropanol (422-05-9), 3-fluoropropanol (462-43-1), hexafluoroisopropanol (920-66-1), 2-allylic hexafluoroisopropanol (646-97-9), 1,3-difluoro-2-propanol (453-13-4), hexafluoro-2-methylisopropanol (1515-14-6), perfluorotert-butanol (2378-02-1), 2-trifluoro One or more of the following: methyl-2-propanol (507-52-8), 2,2-bis(trifluoromethyl)propanol (2927-17-5), 2,2-difluoropropanol (33420-52-9), 1-(4-fluoropropoxy)-2-propanol (307532-03-2), 1,1,1-trifluoro-2-propanol (374-01-6), 3,3,3-trifluoro-1-propanol (2240-88-2), and 2-vinylhexafluoroisopropanol (19701-19-0).

[0012] Preferably, the epoxy compound is one or more selected from ethylene oxide, propylene oxide, 1,2-epoxybutane, 2,3-epoxybutane, and butadiene diepoxide.

[0013] Preferably, the molar ratio of the first component to the second component in the extractant is 1:(0.01 to 100).

[0014] Preferably, the diol compound includes a dihydroxy compound having a carbon number of C2 to C20.

[0015] Preferably, the diol compound may be one or more of the following: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol, 1,2-dihydroxypropionic acid, 1,2-dihydroxypropanal, glycerol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,4-dihydroxy-2-butene, 2-methyl-1,2-propanediol, 3,4-dihydroxy-1-butanoic acid, 1,2-pentanediol, isopentanediol, cyclopentanediol, 1,4-pentanediol, 1,2-hexanediol, cyclohexanediol, 1,2-heptanediol, 1,2-octanediol, cyclooctanediol, 1,2-decanediol, cyclododecanol, phenylethylene glycol, and phenylpropanediol.

[0016] Preferably, the liquid mixture containing the diol compound comprises diol and water, wherein the mass fraction of the diol compound is preferably 1% to 60%, and the mass fraction of water is preferably 40% to 99%.

[0017] Preferably, the weight ratio of the liquid mixture containing the diol compound to the extractant is 1:(0.01-50).

[0018] Preferably, the extraction is carried out at 5–100°C and at atmospheric pressure to 5 MPa (gauge pressure).

[0019] Optionally, it may also include using part or all of the light phase obtained in step a for repeating the extraction process of step a.

[0020] Optionally, the process may also include using part or all of the extractant obtained in step b after separating the heavy phase from the extractant for repeating the extraction process of step a.

[0021] Through the above technical solution, this invention uses an organic extractant to extract and separate diol compounds to obtain high-purity diols. The method of this invention has a simple process flow, is convenient to operate, allows for easy separation of extractant components, has low energy consumption, and produces high diol yield and purity, making it suitable for large-scale production.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof.

[0024] Figure 1 is a schematic diagram of the extraction and separation process of the present invention, wherein A is the extraction tower, 1 and 2 are the feed inlets of diol raw material and extractant, respectively, and 3 and 4 are the discharge outlets of light phase and heavy phase, respectively.

[0025] Figure 2 is a schematic diagram of the heavy phase distillation separation process of the present invention, wherein B is the distillation column, 5 is the heavy phase feed inlet, and 6 and 7 are the extractant phase and diol phase outlets, respectively. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0027] The purpose of this invention is to provide a method for separating liquid mixtures containing diols. This method has a simple process flow, is easy to operate, allows for easy separation of extractant components, has low energy consumption, and produces high diol yield and purity, making it suitable for large-scale production.

[0028] To achieve the above objectives, the present invention provides a method for separating a liquid mixture containing a diol compound, characterized in that the method comprises:

[0029] Step a: The liquid product containing the diol compound is mixed with an extractant and extracted to obtain a heavy phase and a light phase; and Step b: The heavy phase obtained in step a is distilled to obtain the diol compound; wherein the extractant comprises a first component and a second component, the first component has a solubility in water of not less than 1 g / 100 g, the second component has a solubility in water of not less than 0.5 g / 100 g, the first component has a solubility in a mixture of the second component and water of not more than 1 g / 100 g, and the second component has a solubility in a mixture of the first component and water of not more than 1 g / 100 g.

[0030] According to the present invention, unless otherwise specified, the density refers to the density at 20°C and 1 standard atmosphere, and the solubility refers to the solubility at 20°C and 1 standard atmosphere.

[0031] According to the present invention, the first component is preferably a haloalcohol, and the second component is preferably an epoxy compound.

[0032] According to the present invention, the first component haloalcohol has m carbon atoms, where m is preferably a positive integer from 1 to 12, more preferably 2 to 8, and more preferably 3 to 6. In the haloalcohol, a halogen element, a hydroxyl group, and hydrogen are bonded to carbon atoms. The halogen element can be one or more of fluorine, chlorine, bromine, and iodine, preferably one or more of fluorine and chlorine, and more preferably fluorine. The number of halogens in the haloalcohol molecule does not exceed 2m+1, and the number of hydroxyl groups does not exceed 5, preferably not more than 3, and more preferably 1. Atoms in the haloalcohol molecule can be substituted with their isotopes.

[0033] According to the present invention, the carbon atom of the haloalcohol can be saturated carbon or unsaturated carbon, that is, the haloalcohol molecule can contain unsaturated chemical bonds such as double bonds, triple bonds, and benzene rings.

[0034] According to the present invention, the haloalcohol may be 2-fluoroethanol (371-62-0), trifluoroethanol (75-89-8), 1-chloro-2-propanol (127-00-4), 3-chloro-1-propanol (627-30-5), 2-chloro-1-propanol (78-89-7), 1,3-dichloropropanol (96-23-1), 2,3-dichloro-1-propanol (616-23-9), bromopropanol (627-18-9), 2,2,3,3-tetrafluoropropanol (76-37-9), 1H,1H-pentafluoropropanol (422-05-9), 3-fluoropropanol (462-43-1), hexafluoroisopropanol (920-66-1), 1,1,1,3,3,3-hexafluoro- 2-Deuterated propanol (38701-74-5), 2-Allylhexafluoroisopropanol (646-97-9), 1,3-Difluoro-2-propanol (453-13-4), Hexafluoro-2-methylisopropanol (1515-14-6), Perfluorotert-butanol (2378-02-1), 1-Chloro-3-fluoro-2-propanol (453-11-2), 3-Bromo-1,1,1-trifluoro-2-propanol (431-34-5), 2-Trifluoromethyl-2-propanol (507-52-8), 2,2-Bis(trifluoromethyl)propanol (2927-17-5), 2,2-Difluoropropanol (33420-52-9), 3-Bromo-trifluoro-2-propanol (88378-50-1), 1,1,1, 3,3,3-Hexafluoro-2-phenyl-2-propanol (718-64-9), 3-(3-trifluoromethylphenyl)propanol (78573-45-2), 2-(4-fluorophenyl)-2-propanol (402-41-5), 2-[3,5-(bis(trifluoromethyl)phenyl)phenyl]2-propanol (28180-47-4), 1,3-bis(1,1,1,3,3,3-hexafluoro-2-propanol)benzene (802-93-7), 3-perfluorooctylpropanol (1651-41-8), 3-(perfluorohexyl)propanol (80806-68-4), (R)-(+)-1-chloro-3-(4-fluorophenoxy)-2-propanol (307532-04-3), 1-(4-fluoropropoxy)- One or more of the following: 2-propanol (307532-03-2), 1,1,1-trifluoro-2-propanol (374-01-6), 3,3,3-trifluoro-1-propanol (2240-88-2), 2-vinylhexafluoroisopropanol (19701-19-0), 2-(4-aminophenyl)-1,1,1,3,3,3-hexafluoro-2-propanol (722-92-9), hexafluoro-2-(p-tolyl)isopropanol (2010-61-9), 1-(4-trifluoromethylphenyl)-1-propanol (67081-98-5), 3-perfluorobutyl-2-propanol (80233-96-1), and 3-(perfluoro-7-methylhexyl)-2-iodopropanol (65726-35-4).

[0035] According to the present invention, preferably, the haloalcohol may be 1-chloro-2-propanol (127-00-4), 3-chloro-1-propanol (627-30-5), 2-chloro-1-propanol (78-89-7), 1,3-dichloropropanol (96-23-1), 2,3-dichloro-1-propanol (616-23-9), bromopropanol (627-18-9), or 2,2,3,3-tetrafluoropropanol. (76-37-9), 1H,1H-pentafluoropropanol (422-05-9), 3-fluoropropanol (462-43-1), hexafluoroisopropanol (920-66-1), 1,1,1,3,3,3-hexafluoro-2-deuterated propanol (38701-74-5), 2-allylic hexafluoroisopropanol (646-97-9), 1,3-difluoro-2-propanol (453-13-4), hexafluoro 2-Methylisopropanol (1515-14-6), perfluorotert-butanol (2378-02-1), 1-chloro-3-fluoro-2-propanol (453-11-2), 2-trifluoromethyl-2-propanol (507-52-8), 2,2-bis(trifluoromethyl)propanol (2927-17-5), 2,2-difluoropropanol (33420-52-9), 3-bromo-trifluoro-2-propanol (88) One or more of the following: 378-50-1), 1-(4-fluoropropoxy)-2-propanol (307532-03-2), 1,1,1-trifluoro-2-propanol (374-01-6), 3,3,3-trifluoro-1-propanol (2240-88-2), 2-vinylhexafluoroisopropanol (19701-19-0), and 3-perfluorobutyl-2-propanol (80233-96-1).

[0036] According to the present invention, more preferably, the haloalcohol may be 2,2,3,3-tetrafluoropropanol (76-37-9), 1H,1H-pentafluoropropanol (422-05-9), 3-fluoropropanol (462-43-1), hexafluoroisopropanol (920-66-1), 2-allyl hexafluoroisopropanol (646-97-9), 1,3-difluoro-2-propanol (453-13-4), hexafluoro-2-methylisopropanol (1515-14-6), or perfluorotert-butanol (2378-02-1). One or more of the following: 2-trifluoromethyl-2-propanol (507-52-8), 2,2-bis(trifluoromethyl)propanol (2927-17-5), 2,2-difluoropropanol (33420-52-9), 1-(4-fluoropropoxy)-2-propanol (307532-03-2), 1,1,1-trifluoro-2-propanol (374-01-6), 3,3,3-trifluoro-1-propanol (2240-88-2), and 2-vinylhexafluoroisopropanol (19701-19-0).

[0037] According to the present invention, preferably, the second component epoxy compound preferably has n carbon atoms, where n is preferably a positive integer from 2 to 6, and contains at least one epoxy bond. More preferably, the second component epoxy compound is one or more of ethylene oxide, propylene oxide, epichlorohydrin, methyl epichlorohydrin, 1,2-epoxybutane, 2,3-epoxybutane, and butadiene diepoxide.

[0038] Because the extractant used in this invention has special physical properties, it is particularly suitable for separating liquid products containing diols. In this invention, both the first and second components of the extractant can effectively dissolve water and diol compounds. However, when both are present simultaneously, the diol liquid mixture containing the extractant can be rapidly separated into a heavy phase rich in the first component and a light phase rich in water, with the diol and the second component distributed between the two phases. Since the first component generally has a low boiling point and a low molar enthalpy of vaporization, often lower than that of water, the heavy phase can be further distilled to separate the diol enriched in the heavy phase and obtain the first and second components. Furthermore, the extraction step can be repeated on the separated light phase to separate the diol compounds in the light phase.

[0039] This invention does not have special requirements on the content of the first and second components in the extractant, as long as it satisfies the requirement of phase separation of the diol solution. The inventors have discovered that as long as both the first and second components are present simultaneously in the aqueous solution of the diol, phase separation can be achieved regardless of whether the first component is more abundant than the second component, thereby extracting and separating the diol compound. Since a slightly higher first component can carry out more diol, resulting in higher efficiency, it is preferable that the extractant contains a slightly higher first component and a slightly lower second component. For accurate operation, the preferred molar ratio of the first to second components in the extractant is 1:(0.01–100), which can be 1:(0.01–1), preferably 1:(0.05–0.6), more preferably 1:(0.1–0.3), or 1:(1–100), preferably 1:(3–60), more preferably 1:(5–30), all of which can achieve the objective of this invention.

[0040] In this invention, the extractant comprises a first component and a second component. The first component has a solubility in water of not less than 1 g / 100 g, and the second component has a solubility in water of not less than 0.5 g / 100 g. For example, hexafluoroisopropanol has a solubility of 100 g / 100 g in water, 2,2,3,3-tetrafluoropropanol has a solubility of more than 1 g / 100 g in water, perfluorotert-butanol has a solubility of more than 1 g / 100 g in water, 2,3-dichloro-1-propanol has a solubility of 12 g / 100 g in water; propylene oxide has a solubility of more than 1 g / 100 g in water, butadiene diepoxide has a solubility of more than 1 g / 100 g in water, 2,3-epoxybutane has a solubility of 2.8 g / 100 g in water, and ethylene oxide has a solubility of 10 g / 100 g in water.

[0041] In this invention, the solubility of the first component in the mixture of the second component and water is no greater than 1 g / 100 g, for example, within the range of 0.2 g / 100 g to 0.9 g / 100 g, specifically 0.2 g / 100 g, 0.3 g / 100 g, 0.5 g / 100 g, 0.6 g / 100 g, 0.9 g / 100 g, etc. The solubility of the second component in the mixture of the first component and water is no greater than 1 g / 100 g, for example, within the range of 0.2 g / 100 g to 0.9 g / 100 g, specifically 0.2 g / 100 g, 0.3 g / 100 g, 0.5 g / 100 g, 0.6 g / 100 g, 0.9 g / 100 g, etc. More specifically, for example, the solubility of hexafluoroisopropanol in a 10%–40% aqueous solution of propylene oxide is less than 0.5 g / 100 g, and the solubility of propylene oxide in a 60%–90% aqueous solution of hexafluoroisopropanol is less than 0.3 g / 100 g; for example, the solubility of 2,2,3,3-tetrafluoropropanol in a 1%–15% aqueous solution of propylene oxide is less than 1 g / 100 g, and the solubility of propylene oxide in a 30%–60% aqueous solution of 2,2,3,3-tetrafluoropropanol is less than 1 g / 100 g; for example, the solubility of hexafluoroisopropanol in a 20%–60% aqueous solution of butadiene diepoxide is less than 0.5 g / 100 g, and the solubility of butadiene diepoxide in a 60%–90% aqueous solution of hexafluoroisopropanol is less than 0.5 g / 100 g; and for example, perfluorotert-fluoropropanol... The solubility of butanol in a 60%–90% aqueous solution of 2,3-epoxybutane is less than 0.6 g / 100 g; the solubility of 2,3-epoxybutane in a 20%–30% aqueous solution of perfluorotert-butanol is less than 0.9 g / 100 g; for example, the solubility of 2,2,3,3-tetrafluoropropanol in a 60%–80% aqueous solution of propylene oxide is less than 0.7 g / 100 g. The solubility of propane in an aqueous solution of 2,2,3,3-tetrafluoropropanol with a mass fraction of 5%–15% is less than 0.7 g / 100 g; for example, the solubility of hexafluoroisopropanol in an aqueous solution of ethylene oxide with a mass fraction of 20%–30% is less than 0.4 g / 100 g, and the solubility of ethylene oxide in an aqueous solution of 2,2,3,3-tetrafluoropropanol with a mass fraction of 40%–60% is less than 0.5 g / 100 g, and so on.

[0042] According to the present invention, preferably, the diol compound comprises a dihydroxy compound having a carbon number of C2 to C20, wherein the diol has at least two hydroxyl groups on its carbon atoms, and may also have other substituents, such as halogens (e.g., one or more of fluorine, chlorine, bromine, and iodine), ethers, ketones, aldehydes, esters, carboxyls, phenolic hydroxyl groups, nitro groups, and sulfonic acid groups, one or more of these. The number of carbon atoms is preferably C2 to C12, more preferably C2 to C8, and even more preferably C2 to C6.

[0043] According to the present invention, the diol compound is, by way of example only, and may be selected from one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol, 1,2-dihydroxypropionic acid, 1,2-dihydroxypropanal, glycerol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,4-dihydroxy-2-butene, 2-methyl-1,2-propanediol, 3,4-dihydroxy-1-butanoic acid, 1,2-pentanediol, isopentanediol, cyclopentanediol, 1,4-pentanediol, 1,2-hexanediol, cyclohexanediol, 1,2-heptanediol, 1,2-octanediol, cyclooctanediol, 1,2-decanediol, cyclododecanol, phenylethylene glycol, and phenylpropanediol.

[0044] Preferably, the diol compound is selected from one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,4-dihydroxy-2-butene, 2-methyl-1,2-propanediol, 3,4-dihydroxy-1-butyric acid, 1,2-pentanediol, isopentanediol, cyclopentanediol, 1,4-pentanediol, 1,2-hexanediol, and cyclohexanediol.

[0045] More preferably, the diol compound is selected from one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, and 1,2-hexanediol.

[0046] This invention does not impose any particular requirements on the source of the diol-containing liquid mixture. It can be a self-prepared solution, obtained through the hydration reaction of a corresponding epoxide, obtained through epoxidation and ring-opening reactions of a corresponding olefin, obtained through fermentation, an industrial product or intermediate, or a laboratory material; all of these can be separated using the method provided by this invention. Preferably, the diol-containing liquid comprises a diol compound and water. The mass fraction of the diol compound is preferably 1%–60%, more preferably 4%–40%, and even more preferably 6%–30%. The mass fraction of water is preferably 40%–99%, more preferably 6%–96%, and even more preferably 70%–94%. Optionally, the diol-containing liquid may also contain one or more of the following: olefin, hydrogen peroxide, aldehyde, carboxylic acid, ketone, epoxide, ketal, acetal, diol condensate, acid, and base.

[0047] This invention does not impose particular limitations on the operating methods and equipment used in the extraction process. It can be a single or multiple intermittent extraction separation, or a continuous extraction separation. It can be carried out in ordinary containers, stirred tanks, microchannel reactors, tubular reactors, centrifugal reactors, or extraction towers, such as rotating disc towers, packed towers, and sieve plate towers. The extraction equipment used may be without internal components or may have internal components added. Considering the convenience of industrial applications and reducing the harm to operators from organic vapors, continuous extraction separation and extraction separation operations in an extraction tower are preferred. The extraction tower preferably has 1 to 30 theoretical plates.

[0048] To achieve good extraction and separation results, a certain amount of extractant is required. Too little extractant leads to incomplete extraction, while too much extractant results in high energy consumption. According to the present invention, preferably, the weight ratio of the liquid mixture containing the diol compound to the extractant can be 1:(0.01-50), more preferably 1:(1-15), more preferably 1:(2-6), or preferably 1:(0.2-1), more preferably 1:(0.3-0.7).

[0049] According to the present invention, preferably, the extraction temperature is between 5 and 100°C, more preferably between 20 and 60°C, and the extraction pressure is usually in the range of atmospheric pressure to 5 MPa (gauge pressure), preferably at atmospheric pressure.

[0050] According to the present invention, the distillation can be a batch operation or a continuous operation. A distillation vessel, a plate column, or a packed column can be used as the distillation equipment; the present invention has no particular limitations. Distillation separation of the heavy or light phase product is prior art and will not be described in detail here.

[0051] According to the present invention, the extraction process may further include using part or all of the light phase obtained in step a for repeated extraction of step a.

[0052] According to the present invention, the extraction process may further include using part or all of the extractant obtained in step b after separating the heavy phase from the extractant for repeating the extraction process of step a.

[0053] Through the above technical solution, the present invention provides a simple method for separating high-purity diol products from a liquid mixture containing diol compounds using an extractant. The method of the present invention has the following positive effects:

[0054] 1. The process is simple; the raw materials are directly separated by distillation after extraction, requiring no special equipment and making operation convenient.

[0055] 2. The extractant has simple components, is easy to separate from other components in the raw material, has low separation energy consumption, and the separated extractant can be recycled for extraction.

[0056] 3. The method of the present invention has a high yield and high purity of diol compounds.

[0057] Unless otherwise specified, all raw materials used in the examples are chemically pure reagents.

[0058] The reaction products were analyzed by gas chromatography. The chromatographic conditions were as follows: Agilent-7890 chromatograph, HP-INNOWAX capillary column, injection volume 1 μL, injection port temperature 280℃. Column temperature was maintained at 50℃ for 5 min, then increased to 250℃ at a rate of 10℃ / min and held for 25 min. An FID detector was used, with a detector temperature of 300℃.

[0059] In the various embodiments and comparative examples:

[0060] Diol yield = (Mass of diol in the extract / Mass of diol in the feed) × 100%

[0061] Diol purity = (Cyclical peak area of ​​diol in extract / Total peak area) × 100%

[0062] Example 1

[0063] Prepare an aqueous solution of 1,2-propanediol, wherein the mass fraction of 1,2-propanediol is 15% and the mass fraction of water is 85%.

[0064] The extractant was prepared by mixing hexafluoroisopropanol (solubility in water 100g / 100g) and propylene oxide (solubility in water greater than 1g / 100g) at a molar ratio of 1:0.3. Specifically, the solubility of hexafluoroisopropanol in a 10%–40% (w / w) aqueous solution of propylene oxide is less than 0.5g / 100g, and the solubility of propylene oxide in a 60%–90% (w / w) aqueous solution of hexafluoroisopropanol is less than 0.3g / 100g.

[0065] Following the process shown in Figure 1 (tower A), under atmospheric pressure and at 20°C, the extractant and a 1,2-propanediol aqueous solution are introduced into the extraction tower through inlets 1 and 2, respectively, for countercurrent contact extraction. The mass flow ratio of the 1,2-propanediol aqueous solution to the extractant is 1:3. The theoretical number of plates in this extraction tower is 12. Light and heavy phases are obtained at outlets 3 and 4. The light phase mainly contains water and propylene oxide, while the heavy phase mainly contains hexafluoroisopropanol, 1,2-propanediol, a small amount of propylene oxide, and water.

[0066] Following the process shown in column B of Figure 2, the heavy phase was introduced into the distillation column through inlet 5 for distillation separation. The extractant component and the 1,2-propanediol product were obtained from outlets 6 and 7, respectively. The extractant component was returned to column A for continued use as an extractant. The yield and purity analysis results of the 1,2-propanediol product are shown in Table 1.

[0067] Example 2

[0068] Prepare an aqueous solution of 1,2-propanediol, wherein the mass fraction of 1,2-propanediol is 25% and the mass fraction of water is 75%.

[0069] The extractant was prepared by mixing 2,2,3,3-tetrafluoropropanol (water-soluble solubility greater than 1 g / 100 g) and propylene oxide (water-soluble solubility greater than 1 g / 100 g) at a molar ratio of 1:0.2. Specifically, the solubility of 2,2,3,3-tetrafluoropropanol in a 1%–15% (w / w) aqueous solution of propylene oxide is less than 1 g / 100 g, and the solubility of propylene oxide in a 30%–60% (w / w) aqueous solution of 2,2,3,3-tetrafluoropropanol is less than 1 g / 100 g.

[0070] Following the process shown in Figure 1 (tower A), under atmospheric pressure and at 30°C, the extractant and a 1,2-propanediol aqueous solution are introduced into the extraction tower through inlets 1 and 2, respectively, for countercurrent contact extraction. The mass flow ratio of the 1,2-propanediol aqueous solution to the extractant is 1:0.7. The theoretical number of plates in this extraction tower is 15. Light and heavy phases are obtained at outlets 3 and 4. The light phase mainly contains water and propylene oxide, while the heavy phase mainly contains 2,2,3,3-tetrafluoropropanol, 1,2-propanediol, a small amount of propylene oxide, and water.

[0071] Following the process shown in column B of Figure 2, the heavy phase was introduced into the distillation column through inlet 5 for distillation separation. The extractant component and the 1,2-propanediol product were obtained from outlets 6 and 7, respectively. The extractant component was returned to column A for continued use as an extractant. The yield and purity analysis results of the 1,2-propanediol product are shown in Table 1.

[0072] Example 3

[0073] An aqueous solution of 1,2-propanediol was prepared by hydrolysis. Propylene oxide was slowly added to a sulfuric acid solution with a pH of 2.0, and the hydrolysis reaction was carried out with stirring at 50°C to obtain an aqueous solution of 1,2-propanediol. Analysis showed that the mass fraction of 1,2-propanediol was 15%, the mass fraction of water was 84%, and the remainder was dipropylene glycol and tripropylene glycol.

[0074] The extractant was prepared by mixing hexafluoroisopropanol (water solubility 100g / 100g) and butadiene diepoxide (water solubility greater than 1g / 100g) at a molar ratio of 1:0.2. Specifically, the solubility of hexafluoroisopropanol in a 20%–60% (w / w) aqueous solution of butadiene diepoxide is less than 0.5g / 100g, and the solubility of butadiene diepoxide in a 60%–90% (w / w) aqueous solution of hexafluoroisopropanol is less than 0.5g / 100g.

[0075] Following the process shown in Figure 1 (tower A), under conditions of 40℃ and 0.5 MPa, the extractant and a 1,2-propanediol aqueous solution were introduced into the extraction tower through inlets 1 and 2, respectively, for countercurrent contact extraction. The mass flow ratio of the 1,2-propanediol aqueous solution to the extractant was 1:4. The theoretical number of plates in this extraction tower was 7. Light and heavy phases were obtained at outlets 3 and 4. The light phase mainly contained water and butadiene diepoxide, while the heavy phase mainly contained hexafluoroisopropanol, 1,2-propanediol, small amounts of butadiene diepoxide, dipropylene glycol, tripropylene glycol, and water.

[0076] Following the process shown in column B of Figure 2, the heavy phase was introduced into the distillation column through inlet 5 for distillation separation. The extractant component and the 1,2-propanediol product were obtained from outlets 6 and 7, respectively. The extractant component was returned to column A for continued use as an extractant. The yield and purity analysis results of the 1,2-propanediol product are shown in Table 1.

[0077] Example 4

[0078] A 1,2-propanediol solution was prepared according to the method in Example 1 of Chinese Patent CN116789523A. TS-1 molecular sieve, propylene, 30% (w / w) hydrogen peroxide solution, p-toluenesulfonic acid, and water were added to a reaction vessel. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.2:1, the molar ratio of hydrogen peroxide to propylene was 2:1, the molar ratio of p-toluenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.03:1, and the molar ratio of hydrogen peroxide to water was 1:20. The mixture in the reaction vessel was then reacted at 40°C and 1.5 MPa for 5 hours. After the reaction was completed, samples were taken for analysis. The product contained approximately 8% 1,2-propanediol, approximately 4% residual hydrogen peroxide, and approximately 87% water. Small amounts of dipropylene glycol, tripropylene glycol, acetaldehyde, acetic acid, and propylene oxide were also present as byproducts.

[0079] The extractant was prepared by mixing hexafluoroisopropanol (water solubility 100g / 100g) and propylene oxide (water solubility greater than 1g / 100g) at a molar ratio of 1:0.1. Specifically, the solubility of hexafluoroisopropanol in a 5%–20% (w / w) aqueous solution of propylene oxide is less than 0.7g / 100g, and the solubility of propylene oxide in a 60%–90% (w / w) aqueous solution of hexafluoroisopropanol is less than 0.3g / 100g.

[0080] Following the process shown in Figure 1 (tower A), under conditions of 40℃ and 2MPa, the extractant and a 1,2-propanediol aqueous solution were introduced into the extraction tower through inlets 1 and 2, respectively, for countercurrent contact extraction. The mass flow ratio of the 1,2-propanediol aqueous solution to the extractant was 1:3. The theoretical number of plates in this extraction tower was 8. Light and heavy phases were obtained at outlets 3 and 4. The light phase mainly contained water, propylene oxide, and byproducts, while the heavy phase mainly contained hexafluoroisopropanol, 1,2-propanediol, and small amounts of propylene oxide, water, and impurities.

[0081] Following the process shown in column B of Figure 2, the heavy phase was introduced into the distillation column through inlet 5 for distillation separation. The extractant component and the 1,2-propanediol product were obtained from outlets 6 and 7, respectively. The extractant component was returned to column A for continued use as an extractant. The yield and purity analysis results of the 1,2-propanediol product are shown in Table 1.

[0082] Example 5

[0083] Prepare an aqueous solution of 1,3-propanediol, wherein the mass fraction of 1,3-propanediol is 25% and the mass fraction of water is 75%.

[0084] The extractant was prepared by mixing hexafluoroisopropanol (water solubility 100g / 100g) and propylene oxide (water solubility greater than 1g / 100g) at a molar ratio of 1:0.3. Specifically, the solubility of hexafluoroisopropanol in a 10%–40% (w / w) aqueous solution of propylene oxide is less than 0.5g / 100g, and the solubility of propylene oxide in a 60%–90% (w / w) aqueous solution of hexafluoroisopropanol is less than 0.2g / 100g.

[0085] Following the process shown in Figure 1 (tower A), under conditions of 50°C and 2 MPa, the extractant and an aqueous solution of 1,3-propanediol were introduced into the extraction tower through inlets 1 and 2, respectively, for countercurrent contact extraction. The mass flow ratio of the 1,3-propanediol aqueous solution to the extractant was 1:2. The theoretical number of plates in this extraction tower was 8. Light and heavy phases were obtained at outlets 3 and 4. The light phase mainly contained water and propylene oxide, while the heavy phase mainly contained hexafluoroisopropanol, 1,3-propanediol, a small amount of propylene oxide, and water.

[0086] Following the process shown in column B of Figure 2, the heavy phase was introduced into the distillation column through inlet 5 for distillation separation. The extractant component and the 1,3-propanediol product were obtained from outlets 6 and 7, respectively. The extractant component was returned to column A for continued use as an extractant. The yield and purity analysis results of the 1,3-propanediol product are shown in Table 1.

[0087] Example 6

[0088] An aqueous solution of 1,2-butanediol was prepared by hydrolysis. 1,2-epoxybutane was slowly added to a sulfuric acid solution with a pH of 1.75, and the hydrolysis reaction was carried out with stirring at 60°C to obtain an aqueous solution of 1,2-butanediol. Analysis showed that the mass fraction of 1,2-butanediol was 30%, and the mass fraction of water was 70%.

[0089] The extractant was prepared by mixing perfluorotert-butanol (solubility in water greater than 1 g / 100 g) and 2,3-epoxybutane (solubility in water 2.8 g / 100 g) at a molar ratio of 1:5. Specifically, the solubility of perfluorotert-butanol in a 60%–90% (w / w) aqueous solution of 2,3-epoxybutane is less than 0.6 g / 100 g, and the solubility of 2,3-epoxybutane in a 20%–30% (w / w) aqueous solution of perfluorotert-butanol is less than 0.9 g / 100 g.

[0090] Following the process shown in Figure 1 (tower A), under atmospheric pressure and at 40°C, the extractant and a 1,2-butanediol aqueous solution are introduced into the extraction tower through inlets 1 and 2, respectively, for countercurrent contact extraction. The mass flow ratio of the 1,2-butanediol aqueous solution to the extractant is 1:5. The theoretical number of plates in this extraction tower is 10. Light and heavy phases are obtained at outlets 3 and 4. The light phase mainly contains water and 2,3-epoxybutane, while the heavy phase mainly contains perfluorotert-butanol, 1,2-butanediol, a small amount of 2,3-epoxybutane, and water.

[0091] Following the process shown in column B of Figure 2, the heavy phase was introduced into the distillation column through inlet 5 for distillation separation. The extractant component and the 1,2-butanediol product were obtained from outlets 6 and 7, respectively. The extractant component was returned to column A for continued use as an extractant. The yield and purity analysis results of the 1,2-butanediol product are shown in Table 1.

[0092] Example 7

[0093] An aqueous solution of 1,2-hexanediol was prepared by hydrolysis. 1,2-epoxyhexane was slowly added to a sulfuric acid solution with a pH of 1.75, and the hydrolysis reaction was carried out with stirring at 60°C to obtain an aqueous solution of 1,2-hexanediol. Analysis showed that the mass fraction of 1,2-hexanediol was 18%, and the mass fraction of water was 82%.

[0094] The extractant was prepared by mixing 2,2,3,3-tetrafluoropropanol (solubility in water greater than 1 g / 100 g) and propylene oxide (solubility in water greater than 1 g / 100 g) at a molar ratio of 1:30. Specifically, the solubility of 2,2,3,3-tetrafluoropropanol in a 60%–80% (w / w) aqueous solution of propylene oxide is less than 0.7 g / 100 g, and the solubility of propylene oxide in a 5%–15% (w / w) aqueous solution of 2,2,3,3-tetrafluoropropanol is less than 0.7 g / 100 g.

[0095] Following the process shown in Figure 1 (tower A), under conditions of 60℃ and 0.5 MPa, the extractant and a 1,2-hexanediol aqueous solution were introduced into the extraction tower through inlets 1 and 2, respectively, for countercurrent contact extraction. The mass flow ratio of the 1,2-hexanediol aqueous solution to the extractant was 1:2. The theoretical number of plates in this extraction tower was 15. Light and heavy phases were obtained at outlets 3 and 4. The light phase mainly contained water and propylene oxide, while the heavy phase mainly contained 2,2,3,3-tetrafluoropropanol, 1,2-hexanediol, and small amounts of propylene oxide and water.

[0096] Following the process shown in column B of Figure 2, the heavy phase was introduced into the distillation column through inlet 5 for distillation separation. The extractant component and the 1,2-hexanediol product were obtained from outlets 6 and 7, respectively. The extractant component was returned to column A for continued use as an extractant. The yield and purity analysis results of the 1,2-hexanediol product are shown in Table 1.

[0097] Example 8

[0098] Prepare an aqueous solution of ethylene glycol, wherein the mass fraction of ethylene glycol is 10% and the mass fraction of water is 90%.

[0099] The extractant was prepared by mixing hexafluoroisopropanol (solubility in water: 100 g / 100 g) and ethylene oxide (solubility in water: 10 g / 100 g) at a molar ratio of 1:0.2. Specifically, the solubility of hexafluoroisopropanol in a 20%–30% (w / w) aqueous solution of ethylene oxide is less than 0.4 g / 100 g, and the solubility of ethylene oxide in a 40%–60% (w / w) aqueous solution of 2,2,3,3-tetrafluoropropanol is less than 0.5 g / 100 g.

[0100] Following the process shown in Figure 1 (tower A), under atmospheric pressure and at 30°C, the extractant and ethylene glycol aqueous solution are introduced into the extraction tower through inlets 1 and 2, respectively, for countercurrent contact extraction. The mass flow ratio of the ethylene glycol aqueous solution to the extractant is 1:6. The theoretical number of plates in this extraction tower is 12. Light and heavy phases are obtained at outlets 3 and 4. The light phase mainly contains water and ethylene oxide, while the heavy phase mainly contains hexafluoroisopropanol, ethylene glycol, and small amounts of ethylene oxide and water.

[0101] Following the process shown in column B of Figure 2, the heavy phase was introduced into the distillation column through inlet 5 for distillation separation. The extractant component and ethylene glycol product were obtained from outlets 6 and 7, respectively. The extractant component was returned to column A for continued use as an extractant. The yield and purity analysis results of the ethylene glycol product are shown in Table 1.

[0102] Example 9

[0103] Prepare an aqueous solution of ethylene glycol, wherein the mass fraction of ethylene glycol is 6% and the mass fraction of water is 94%.

[0104] The extractant was prepared by mixing hexafluoroisopropanol (solubility in water 100 g / 100 g) and propylene oxide (solubility in water greater than 1 g / 100 g) at a molar ratio of 1:0.3. Specifically, the solubility of hexafluoroisopropanol in a 10%–30% (w / w) aqueous solution of propylene oxide is less than 0.5 g / 100 g, and the solubility of propylene oxide in a 40%–60% (w / w) aqueous solution of hexafluoroisopropanol is less than 0.4 g / 100 g. Following the flow diagram shown in Figure 1 (tower A), at 20°C and 1 MPa, the extractant and ethylene glycol aqueous solution were introduced into the extraction tower through inlets 1 and 2, respectively, for countercurrent contact extraction. The mass flow ratio of ethylene glycol aqueous solution to extractant was 1:3. The theoretical number of plates in the extraction tower was 10. The light and heavy phases were separated at outlets 3 and 4. The light phase mainly contains water and propylene oxide, while the heavy phase mainly contains hexafluoroisopropanol, ethylene glycol, and small amounts of propylene oxide and water.

[0105] Following the process shown in column B of Figure 2, the heavy phase was introduced into the distillation column through inlet 5 for distillation separation. The extractant component and ethylene glycol product were obtained from outlets 6 and 7, respectively. The extractant component was returned to column A for continued use as an extractant. The yield and purity analysis results of the ethylene glycol product are shown in Table 1.

[0106] Example 10

[0107] Prepare an aqueous solution of 1,2-propanediol, wherein the mass fraction of 1,2-propanediol is 15% and the mass fraction of water is 85%.

[0108] The extractant was prepared by mixing 2,3-dichloro-1-propanol (solubility in water: 12 g / 100 g) and propylene oxide (solubility in water: greater than 1 g / 100 g) at a molar ratio of 1:0.3. Specifically, the solubility of 2,3-dichloro-1-propanol in a 20%–40% (w / w) aqueous solution of propylene oxide is less than 1.0 g / 100 g, and the solubility of propylene oxide in a 40%–60% (w / w) aqueous solution of 2,3-dichloro-1-propanol is less than 1.0 g / 100 g.

[0109] Following the process shown in Figure 1 (tower A), under atmospheric pressure and at 20°C, the extractant and a 1,2-propanediol aqueous solution are introduced into the extraction tower through inlets 1 and 2, respectively, for countercurrent contact extraction. The mass flow ratio of the 1,2-propanediol aqueous solution to the extractant is 1:3. The theoretical number of plates in this extraction tower is 12. Light and heavy phases are obtained at outlets 3 and 4. The light phase mainly contains water and propylene oxide, while the heavy phase mainly contains hexafluoroisopropanol, 1,2-propanediol, a small amount of propylene oxide, and water.

[0110] Following the process shown in column B of Figure 2, the heavy phase was introduced into the distillation column through inlet 5 for distillation separation. The extractant component and the 1,2-propanediol product were obtained from outlets 6 and 7, respectively. The extractant component was returned to column A for continued use as an extractant. The yield and purity analysis results of the 1,2-propanediol product are shown in Table 1.

[0111] Comparative Example 1

[0112] The 1,2-propanediol aqueous solution prepared in Example 1 was subjected to conventional distillation to remove water under normal pressure. The product collected from the bottom of the distillate was analyzed and found to be yellowish and contained condensation polymers. The yield and purity analysis results of the 1,2-propanediol product are shown in Table 1.

[0113] Table 1

[0114] Diol Compound Number | Diol Compound Yield | Diol Compound Purity | Example 1 | 99.10% | 99.30% | Example 2 | 99.30% | 99.40% | Example 3 | 99.10% | 95.80% | Example 4 | 99.40% | 95.50% | Example 5 | 99.50% | 99.60% | Example 6 | 99.80% | 99.80% | Example 7 | 99.40% | 99.90% | Example 8 | 99.80% | 99.30% | Example 9 | 99.40% | 99.10% | Example 10 | 94.50% | 93.80% | Comparative Example 1 | 90.50% | 91.10% surface

[0115] As can be seen from the results of Examples 1-10, the method of the present invention for separating diol liquid products has a simple process flow, requires no special equipment, has a simple extractant composition, is easy to separate from other products in the raw materials, and the aqueous phase and extractant phase after separation can be reused respectively. Therefore, the material utilization rate is high and it is suitable for large-scale industrial production applications.

Claims

1. A method for separating a liquid mixture containing a diol compound, characterized in that, The method includes: step a: mixing a liquid product containing a diol compound with an extractant and then extracting it to obtain a heavy phase and a light phase; and step b: distilling the heavy phase obtained in step a to obtain the diol compound; wherein the extractant includes a first component and a second component, the first component having a solubility in water of not less than 1 g / 100 g, the second component having a solubility in water of not less than 0.5 g / 100 g, the first component having a solubility in a mixture of the second component and water of not more than 1 g / 100 g, and the second component having a solubility in a mixture of the first component and water of not more than 1 g / 100 g.

2. The method according to claim 1, characterized in that, The first component is a haloalcohol, and the second component is an epoxy compound.

3. The method according to claim 2, characterized in that, The haloalcohol has m carbon atoms, where m is a positive integer from 1 to 12, preferably 2 to 8, and more preferably 3 to 6. In the haloalcohol, the halogen element, hydroxyl group, and hydrogen are bonded to the carbon atoms. The halogen element is one or more of fluorine, chlorine, bromine, and iodine, and its number does not exceed 2m+1. The number of hydroxyl groups does not exceed 5, preferably not more than 3, and more preferably 1.

4. The method according to claim 3, characterized in that, The halogen element of the haloalcohol is fluorine.

5. The method according to claim 2, characterized in that, The haloalcohol is selected from 2-fluoroethanol, trifluoroethanol, 1-chloro-2-propanol, 3-chloro-1-propanol, 2-chloro-1-propanol, 1,3-dichloropropanol, 2,3-dichloro-1-propanol, bromopropanol, 2,2,3,3-tetrafluoropropanol, 1H,1H-pentafluoropropanol, 3-fluoropropanol, hexafluoroisopropanol, 1,1,1,3,3,3-hexafluoro-2-deuterated propanol, and 2-allyl hexafluoroisopropanol. 1,3-Difluoro-2-propanol, hexafluoro-2-methylisopropanol, perfluorotert-butanol, 1-chloro-3-fluoro-2-propanol, 3-bromo-1,1,1-trifluoro-2-propanol, 2-trifluoromethyl-2-propanol, 2,2-bis(trifluoromethyl)propanol, 2,2-difluoropropanol, 3-bromo-trifluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-phenyl-2-propanol, 3-(3-trifluoro-2-propanol) 2-(4-fluorophenyl)-2-propanol, 2-[3,5-(bis(trifluoromethyl)phenyl)-2-propanol), 1,3-bis(1,1,1,3,3,3-hexafluoro-2-propanol)benzene, 3-perfluorooctylpropanol, 3-(perfluorohexyl)propanol, (R)-(+)-1-chloro-3-(4-fluorophenoxy)-2-propanol, 1-(4-fluoropropoxy)-2-propanol, 1 One or more of the following: 1,1-trifluoro-2-propanol, 3,3,3-trifluoro-1-propanol, 2-vinylhexafluoroisopropanol, 2-(4-aminophenyl)-1,1,1,3,3,3-hexafluoro-2-propanol, hexafluoro-2-(p-tolyl)isopropanol, 1-(4-trifluoromethylphenyl)-1-propanol, 3-perfluorobutyl-2-propanol, and 3-(perfluoro-7-methylhexyl)-2-iodopropanol.

6. The method according to claim 2, characterized in that, The haloalcohol is selected from 1-chloro-2-propanol, 3-chloro-1-propanol, 2-chloro-1-propanol, 1,3-dichloropropanol, 2,3-dichloro-1-propanol, bromopropanol, 2,2,3,3-tetrafluoropropanol, 1H,1H-pentafluoropropanol, 3-fluoropropanol, hexafluoroisopropanol, 1,1,1,3,3,3-hexafluoro-2-deuterated propanol, 2-allyl hexafluoroisopropanol, 1,3-difluoro-2-propanol, hexafluoro-2- One or more of the following: methyl isopropanol, perfluorotert-butanol, 1-chloro-3-fluoro-2-propanol, 2-trifluoromethyl-2-propanol, 2,2-bis(trifluoromethyl)propanol, 2,2-difluoropropanol, 3-bromo-trifluoro-2-propanol, 1-(4-fluoropropoxy)-2-propanol, 1,1,1-trifluoro-2-propanol, 3,3,3-trifluoro-1-propanol, 2-vinylhexafluoroisopropanol, and 3-perfluorobutyl-2-propanol.

7. The method according to claim 2, characterized in that, The haloalcohol is selected from one or more of the following: 2,2,3,3-tetrafluoropropanol, 1H,1H-pentafluoropropanol, 3-fluoropropanol, hexafluoroisopropanol, 2-allylhexafluoroisopropanol, 1,3-difluoro-2-propanol, hexafluoro-2-methylisopropanol, perfluorotert-butanol, 2-trifluoromethyl-2-propanol, 2,2-bis(trifluoromethyl)propanol, 2,2-difluoropropanol, 1-(4-fluoropropoxy)-2-propanol, 1,1,1-trifluoro-2-propanol, 3,3,3-trifluoro-1-propanol, and 2-vinylhexafluoroisopropanol.

8. The method according to claim 2, characterized in that, The epoxy compound has n carbon atoms, where n is a positive integer from 2 to 6, and contains at least one epoxy bond.

9. The method according to claim 2, characterized in that, The epoxy compound is selected from one or more of ethylene oxide, propylene oxide, 1,2-epoxybutane, 2,3-epoxybutane, and butadiene diepoxide.

10. The method according to claim 1, characterized in that, The molar ratio of the first component to the second component in the extractant is 1:(0.01-100), preferably 1:(0.01-1), more preferably 1:(0.05-0.6), and most preferably 1:(0.1-0.3).

11. The method according to claim 1, characterized in that, The molar ratio of the first component to the second component in the extractant is 1:(1-100), preferably 1:(3-60), and more preferably 1:(5-30).

12. The method according to claim 1, characterized in that, The diol compound includes dihydroxy compounds with C2 to C20 carbon atoms, preferably C2 to C12, more preferably C2 to C8, and even more preferably C2 to C6.

13. The method according to claim 1, characterized in that, The diol compound is selected from ethylene glycol, 1,2-propanediol, 1,3-propanediol, 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol, 1,2-dihydroxypropionic acid, 1,2-dihydroxypropanal, glycerol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,4-dihydroxy-2-butene, 2-methyl-1,2-propanediol, 3,4-dihydroxy-1-butanoic acid, 1,2-pentanediol, isopentanediol, cyclopentanediol, 1,4-pentanediol, 1,2-hexanediol, cyclohexanediol, 1,2-heptanediol, 1,2-octanediol, cyclooctanediol, 1,2-decanediol, cyclododecanol, phenylethylene glycol, and phenylpropylene glycol. One or more of the following: preferably, the diol is selected from ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,4-dihydroxy-2-butene, 2-methyl-1,2-propanediol, 3,4-dihydroxy-1-butyric acid, 1,2-pentanediol, isopentanediol, cyclopentanediol, 1,4-pentanediol, 1,2-hexanediol, and cyclohexanediol; more preferably, the diol is selected from ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, and 1,2-hexanediol.

14. The method according to claim 1, characterized in that, The liquid mixture containing the diol compound comprises the diol compound and water, wherein the mass fraction of the diol compound is 1% to 60%, preferably 4% to 40%, more preferably 6% to 30%, and the mass fraction of the water is 40% to 99%, preferably 60% to 96%, more preferably 70% to 94%.

15. The method according to claim 14, characterized in that, The liquid mixture containing diol compounds also contains one or more of the following: olefins, hydrogen peroxide, aldehydes, carboxylic acids, ketones, epoxy compounds, ketals, acetals, diol condensates, acids, and bases.

16. The method according to claim 1, characterized in that, The weight ratio of the liquid mixture containing the diol compound to the extractant is 1:(0.01-50), preferably 1:(1-15), more preferably 1:(2-6), even more preferably 1:(0.2-1), and most preferably 1:(0.3-0.7).

17. The method according to claim 1, characterized in that, The extraction described in step a is carried out at 5–100°C, preferably 20–60°C, and at atmospheric pressure to 5 MPa, preferably atmospheric pressure.

18. The method according to claim 1, characterized in that, The method also includes using part or all of the light phase obtained in step a to repeat the extraction process of step a.

19. The method according to claim 1, characterized in that, The method may also include using part or all of the extractant obtained in step b after separating the heavy phase from the extractant for repeating the extraction process of step a.

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