Synthetic method of halogenated ethane

Abstract

The invention provides a synthetic method of halogenated ethane, which comprises the following steps: carrying out first reaction on halogenated propane and halogenated propionic acid under the action of a catalyst to obtain a propionyl halide compound; and carrying out second reaction on the propionyl halide compound and alkali metal halide salt to obtain halogenated ethane. According to the synthetic method of halogenated ethane, halogenated propane, halogenated propionic acid and alkali metal halide salt are used as raw materials, halogenated ethane can be obtained through two-step reaction, the use of dangerous chemical iodine chloride is avoided, the harm to personnel, equipment and environment can be avoided or reduced, and industrial production is easy to realize; meanwhile, the target product selectivity is high.

Description

Technical Field

[0001] The present application relates to the technical field of organic compound synthesis, and in particular to a method for synthesizing halogenated ethane. Background Art

[0002] 1-Chloro-1,1-difluoro-2-iodoethane (hereinafter referred to as CFIE), English name 1-chloro-1,1-difluoro-2-iodoethane, CAS: 463-99-0, structural formula: CF2ClCH2I, relative density: 2.166, boiling point 92.3℃ (624mmHg). This compound is an important intermediate in organic synthesis, mainly used for the preparation of fluorine-containing monomers, the introduction of difluorochloroethyl groups into drug molecules, etc.

[0003] CFIE can be used to synthesize 1,1-difluoro-2-iodoethylene, which is an important monomer for preparing fluorinated elastomers. It can introduce cross-linkable active groups into fluorinated elastomers, making them vulcanizable with peroxides, thereby preparing vulcanized products with outstanding low-temperature resistance.

[0004] There are no industrialized CFIE products for sale in China, which has greatly restricted the production of domestic fluorinated elastomers and the research and development of new drug molecules.

[0005] Existing literature reports on the synthesis of CFIE, all of which use iodine chloride and vinylidene fluoride to synthesize 1-chloro-1,1-difluoro-2-iodoethane (for example: CN112062651A, CN1431248A, CN1186814A, etc.). The reaction equation is as follows:

[0006] ICl+CF2=CH2→CF2ClCH2I

[0007] However, the raw material iodine chloride mentioned in these documents is a dangerous compound. It is not only highly toxic, with an acute toxicity of LD50: 50 mg / kg (rat oral), but it is also easy to absorb water and deteriorate, releasing a large amount of corrosive gas when absorbing water. Moreover, the solidification point of iodine chloride is 25°C, and it is easy to solidify when the weather is cold, which makes it difficult to add materials. When iodine chloride is at a higher temperature (≥27°C), although it can be converted into a reddish-brown liquid, it is easy to volatilize, has strong water absorption, and is easy to decompose. At the same time, iodine chloride has a very high permeability to various plastic packaging (including fluorinated plastic barrels), and is very corrosive to metal packaging containers, which is very easy to cause product leakage. Although glass bottles or porcelain bottles can be used for packaging, the use of glass bottles or porcelain bottles will cause difficulties in the packaging, storage, transportation, handling, and use of the compound, and is very unsuitable for industrial production. Once leaked, it is extremely harmful not only to personnel (strong toxicity), equipment (strong corrosiveness), and the environment (reddish-brown smoke billows and is difficult to dissipate).

[0008] Therefore, it is necessary to find a new production method suitable for the industrial production of CFIE to avoid the use of iodine chloride, which is more harmful, and reduce the harm to personnel, equipment, and the environment. Summary of the invention

[0009] In view of this, the present application aims to provide a method for synthesizing halogenated ethane, which uses halogenated propane, halogenated propionic acid and alkali metal halide as raw materials, and can obtain halogenated ethane through a two-step reaction. The synthesis method avoids the use of hazardous chemical iodine chloride, can avoid or reduce harm to personnel, equipment and the environment, and is easy to realize industrial production; at the same time, the target product has high selectivity.

[0010] To this end, the first aspect of the present application proposes a method for synthesizing halogenated ethane, comprising:

[0011] The halogenated propane is first reacted with the halogenated propionic acid under the action of a catalyst to obtain a propionyl halide compound;

[0012] The propionyl halide compound is subjected to a second reaction with an alkali metal halide salt to obtain the halogenated ethane.

[0013] In some embodiments, the halogenated propane includes at least one of 1,1,1,3-tetrachloro-3,3-difluoropropane and 1,1,3-trichloro-1,3,3-trifluoropropane.

[0014] Preferably, the 1,1,1,3-tetrachloro-3,3-difluoropropane and 1,1,3-trichloro-1,3,3-trifluoropropane are intermediates in the production process of 1,1,1,3,3,3-hexafluoropropane.

[0015] In some embodiments, the catalyst comprises a metal oxide.

[0016] In some embodiments, the metal oxide includes but is not limited to at least one of ferric oxide, ferrosoferric oxide, aluminum oxide, nickel oxide, titanium oxide, and the like.

[0017] In some embodiments, the halopropionic acid is 3-chloro-3,3-difluoropropionic acid.

[0018] In some embodiments, the propionyl halide compound includes 3,3-difluoro-3-chloro-propionyl halide.

[0019] In some embodiments, the 3,3-difluoro-3-chloro-propionyl halide includes, but is not limited to, at least one of 3-chloro-3,3-difluoropropionyl chloride, 3-chloro-3,3-difluoropropionyl fluoride, and the like.

[0020] In some embodiments, the alkali metal halide salt includes but is not limited to at least one of anhydrous sodium iodide, anhydrous potassium iodide, anhydrous lithium iodide, anhydrous cesium iodide, and the like.

[0021] In some embodiments, the first reaction is an oxidation reaction.

[0022] In some embodiments, the temperature of the first reaction is 110-140°C.

[0023] In some embodiments, the first reaction time is 2-6 hours.

[0024] In some embodiments, the absolute pressure of the first reaction is 0.1-0.3 MPa.

[0025] In some embodiments, the reaction temperature of the second reaction is 150-300°C.

[0026] In some embodiments, the reaction time of the second reaction is 3-9 hours.

[0027] In some embodiments, the absolute pressure of the second reaction is 1.5-4.5 MPa.

[0028] In some embodiments, the molar ratio of the halopropionic acid to the halopropane is (0.95-1.2):1.

[0029] In some embodiments, the molar ratio of the catalyst to the halogenated propane is 1:(10-30).

[0030] In some embodiments, the molar ratio of the alkali metal halide salt to the propionyl halide compound is (1.5-2.5):1.

[0031] In some embodiments, the ethane halides include 1-chloro-1,1-difluoro-2-iodoethane.

[0032] The synthesis method of halogenated ethane described in the present application can at least bring the following beneficial effects:

[0033] 1. Using halogenated propane, halogenated propionic acid and alkali metal halide as raw materials, halogenated ethane can be obtained through a two-step reaction. This synthesis method avoids the use of hazardous chemicals such as iodine chloride, can avoid or reduce harm to personnel, equipment and the environment, and is easy to achieve industrial production; at the same time, the target product has high selectivity.

[0034] 2. Using the intermediates 1,1,1,3-tetrachloro-3,3-difluoropropane and 1,1,3-trichloro-1,3,3-trifluoropropane in the production process of F236fa as raw materials can effectively increase the added value of the product.

[0035] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings.

[0037] in:

[0038] Figure 1 This is a summary table of the gas chromatography-mass spectrometry (GC-MS) analysis results of the target product CFEI synthesized in Example 1.

[0039] Figure 2 for Figure 1 The MS graph and judgment of the peak position at 7.905 points in the GC-MS analysis result diagram.

[0040] Figure 3 for Figure 1 The MS graph and judgment of the peak position at 11.751 minutes in the GC-MS analysis result graph.

[0041] Figure 4 for Figure 1 The MS graph and judgment of the peak position at 12.406 minutes in the GC-MS analysis result diagram.

[0042] Figure 5 for Figure 1 The MS graph and judgment of the peak position at 17.217 minutes in the GC-MS analysis result diagram. DETAILED DESCRIPTION

[0043] The embodiments of the present application are described in detail below. The embodiments are exemplary and intended to be used to explain the present application, but should not be construed as limiting the present application.

[0044] In this application, the disclosure of numerical ranges includes all values ​​within the entire range and the disclosure of further subdivided ranges, including the endpoints and sub-ranges given in these ranges.

[0045] In this application, the raw materials, equipment, etc. involved, unless otherwise specified, are all raw materials and equipment that can be made through commercial channels or known methods; the methods involved, unless otherwise specified, are all conventional methods.

[0046] The term "and / or", when used in a list of two or more items, means that any of the listed items can be used alone or in combination with any one or more of the listed items. For example, the expression "A and / or B" is intended to mean A or B or A and B, that is, only A, only B, or a combination of A and B.

[0047] In this application, the reaction pressures involved are all absolute pressures.

[0048] The method for synthesizing halogenated ethane in the embodiment of the present application includes step S101 and step S102, specifically:

[0049] S101, subjecting a halogenated propane to a first reaction with a halogenated propionic acid in the presence of a catalyst to obtain a propionyl halide compound.

[0050] In some embodiments, the halogenated propane includes but is not limited to at least one of 1,1,1,3-tetrachloro-3,3-difluoropropane, 1,1,3-trichloro-1,3,3-trifluoropropane, and the like.

[0051] As a preferred example, the 1,1,1,3-tetrachloro-3,3-difluoropropane and 1,1,3-trichloro-1,3,3-trifluoropropane are intermediates in the production process of 1,1,1,3,3,3-hexafluoropropane (F236fa, CAS#690-39-1).

[0052] As an optional example, the halogenated propane is at least one of 1,1,1,3-tetrachloro-3,3-difluoropropane and 1,1,3-trichloro-1,3,3-trifluoropropane.

[0053] It should be noted that in the embodiments of the present application, when the halogenated propane includes both 1,1,1,3-tetrachloro-3,3-difluoropropane and 1,1,3-trichloro-1,3,3-trifluoropropane, the mass ratio of 1,1,1,3-tetrachloro-3,3-difluoropropane and 1,1,3-trichloro-1,3,3-trifluoropropane can be any mass ratio. When an intermediate in the production process of F236fa is used, its mass ratio will vary depending on the separation conditions of the F236fa process.

[0054] In some embodiments, the catalyst comprises a metal oxide.

[0055] Exemplarily, the metal oxide includes but is not limited to at least one of ferric oxide, ferroferric oxide, aluminum oxide, nickel oxide, titanium oxide, etc., preferably ferric oxide.

[0056] In some embodiments, the molar ratio of the catalyst to the halogenated propane is 1: (10-30), including but not limited to 1: 10, 1: 15, 1: 20, 1: 25 or 1: 30, etc., preferably 1: 20. When the molar ratio of the catalyst to the halogenated propane is within the above range, a higher conversion rate of the raw material can be achieved, and excessive impurities caused by increased side reactions can be avoided (see the reaction equation of side reaction 1 below); if it is higher than 1: 10 (such as 1: 9, 1: 8...), the catalyst is excessive, resulting in increased side reactions (see side reaction 1 below), and the subsequent separation of increased impurities is difficult; if it is lower than 1: 30 (such as 1: 31, 1: 32...), the catalyst is too little, resulting in incomplete conversion of the raw material.

[0057] In some embodiments, the halopropionic acid is 3-chloro-3,3-difluoropropionic acid.

[0058] In some embodiments, the molar ratio of the halogenated propionic acid to the halogenated propane is (0.95-1.2):1, including but not limited to 0.95:1, 1:1, 1.05:1, 1.1:1, 1.15:1 or 1.2:1, etc., preferably 1.1:1. The molar ratio of the halogenated propionic acid to the halogenated propane is within the above range to ensure that the halogenated propane reacts completely while avoiding the generation of halogenated propionic anhydride (see side reaction 2 below for the reaction equation), resulting in raw material loss; if it is lower than 0.95:1, the halogenated propane reacts incompletely; if it is higher than 1.2:1, a certain amount of halogenated propionic anhydride is generated, resulting in raw material loss (see side reaction 2 below).

[0059] In some embodiments, the propionyl halide compound includes 3,3-difluoro-3-chloro-propionyl halide.

[0060] Exemplarily, 3,3-difluoro-3-chloro-propionyl halide includes but is not limited to at least one of 3-chloro-3,3-difluoropropionyl chloride (also known as 3,3-difluoro-3-chloro-propionyl chloride), 3-chloro-3,3-difluoropropionyl fluoride (also known as 3,3-difluoro-3-chloro-propionyl fluoride), and the like.

[0061] In some embodiments, the first reaction is an oxidation reaction.

[0062] In some embodiments, the temperature of the first reaction is 110-140° C., including but not limited to 110° C., 120° C., 130° C. or 140° C., etc., preferably 130° C. The temperature of the first reaction is within the above range to avoid the highest conversion rate and selectivity; if it is lower than 110° C., the conversion rate is low and more raw materials are not converted; if it is higher than 140° C., the conversion rate increases, but impurities are generated and the selectivity is significantly reduced.

[0063] In some embodiments, the first reaction time is 2-6 hours, including but not limited to 2 hours, 3 hours, 4 hours, 5 hours or 6 hours, preferably 4 hours.

[0064] In some embodiments, the absolute pressure of the first reaction is within 0.3 MPa, including but not limited to 0.1 MPa, 0.15 MPa, 0.2 MPa or 0.25 MPa, etc.

[0065] Exemplarily, the absolute pressure of the first reaction is 0.1-0.3 MPa.

[0066] The halogenated propane is 1,1,1,3-tetrachloro-3,3-difluoropropane or / and 1,1,3-trichloro-1,3,3-trifluoropropane, which reacts with 3-chloro-3,3-difluoropropionic acid. The reaction equation of the first reaction is as follows:

[0067]

[0068] Herein, cat. represents a catalyst, which may be at least one of the aforementioned ferric oxide, ferrosoferric oxide, nickel oxide, titanium oxide, etc.

[0069] The side reaction equation of the first reaction is as follows:

[0070]

[0071] Direct hydrolysis of the propionyl halide compound can obtain 3-chloro-3,3-difluoropropionic acid, which can be used as a raw material for the first reaction. This process is a conventional reaction and the operation is relatively simple, so this application will not provide a detailed description. The reaction equation is as follows:

[0072]

[0073] S102, subjecting the propionyl halide compound to a second reaction with an alkali metal halide salt to obtain the ethane halide.

[0074] In the second reaction described in the present application, the raw material propionyl halide compound used can be the reaction product of the first reaction (without distillation, in which the total mass percentage of the acyl halide compound reaches more than 90%), or it can be the reaction product of the first reaction after distillation to achieve a total mass percentage of the acyl halide compound reaching more than 90%.

[0075] In some embodiments, the alkali metal halide salt comprises an alkali metal iodide salt (MI).

[0076] Exemplarily, the alkali metal iodide salt (MI) includes, but is not limited to, at least one of anhydrous sodium iodide, anhydrous potassium iodide, anhydrous lithium iodide, anhydrous cesium iodide, and the like.

[0077] In some embodiments, the reaction temperature of the second reaction is 150-300° C., including but not limited to 175° C., 200° C., 225° C., 250° C., 275° C. or 300° C., preferably 200° C. The temperature of the second reaction within the above range can ensure a higher conversion rate and selectivity; if it is lower than 150° C., the conversion rate is significantly reduced; if it is higher than 300° C., the selectivity is reduced.

[0078] In some embodiments, the reaction time of the second reaction is 3-9 hours, including but not limited to 4 hours, 5 hours, 6 hours, 7 hours or 8 hours, preferably 6 hours.

[0079] In some embodiments, the absolute pressure of the second reaction is 1.5-4.5 MPa, including but not limited to 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa or 4 MPa, etc., preferably 3 MPa.

[0080] In some embodiments, the molar ratio of the alkali metal halide to the propionyl halide compound is (1.5-2.5):1, including but not limited to 1.5:1, 1.75:1, 2:1, 2.25:1 or 2.5:1, etc., preferably 2:1. When the molar ratio of the alkali metal halide to the propionyl halide compound is within the above range, a high conversion rate can be ensured while reducing the difficulty of subsequent separation; if it is lower than 1.5:1, the raw material conversion is incomplete; if it is higher than 2.5:1, there are too many solids after the reaction is completed, and more products are adsorbed by the solids, which makes separation difficult, resulting in a decrease in the actual yield.

[0081] In some embodiments, the ethane halides include 1-chloro-1,1-difluoro-2-iodoethane.

[0082] Taking the alkali metal halide as alkali metal iodide (MI) as an example, the reaction equation of the second reaction is:

[0083]

[0084] Among them, M in MI can be at least one of the alkali metal elements such as Li, Na, K, Cs, etc.

[0085] The synthesis method of halogenated ethane in the embodiment of the present application uses halogenated propane, halogenated propionic acid and alkali metal halide as raw materials, and halogenated ethane can be obtained through two-step reaction. The synthesis method avoids the use of hazardous chemical iodine chloride, can avoid or reduce the harm to personnel, equipment and environment, and is easy to achieve industrial production; at the same time, the target product has high selectivity. In addition, using the intermediates 1,1,1,3-tetrachloro-3,3-difluoropropane and 1,1,3-trichloro-1,3,3-trifluoropropane in the production process of F236fa as raw materials can effectively increase the added value of the product.

[0086] Certain features of the present technology are further illustrated in the following non-limiting examples.

[0087] In the following embodiments, for the convenience of description, 1,1,1,3-tetrachloro-3,3-difluoropropane will become F232fa, 1,1,3-trichloro-1,3,3-trifluoropropane will be referred to as F233fa, 3-chloro-3,3-difluoropropionyl chloride in raw material 3 will be referred to as acyl chloride, 3-chloro-3,3-difluoropropionyl fluoride will be referred to as acyl fluoride, and 1-chloro-1,1-difluoro-2-iodoethane will be referred to as CFIE. At the same time, the raw material halogenated propane participating in the first reaction is defined as raw material 1, the raw material halogenated propionic acid participating in the first reaction is defined as raw material 2, the propionyl halide compound participating in the second reaction is defined as raw material 3, and the alkali metal halide salt participating in the second reaction is defined as raw material 4. Among them, raw material 1 is 1,1,1,3-tetrachloro-3,3-difluoropropane (abbreviated as F232fa) and 1,1,3-trichloro-1,3,3-trifluoropropane (abbreviated as F233fa), raw material 2 is 3-chloro-3,3-difluoropropionic acid, and raw material 3 is 3-chloro-3,3-difluoropropionyl chloride (abbreviated as acyl chloride) and 3-chloro-3,3-difluoropropionyl fluoride (abbreviated as acyl fluoride).

[0088] The term "about" in the following embodiments refers to a fluctuation of 3% between the corresponding numerical value and the numerical value. For example, about 10 mol refers to 9.7-10.3 mol.

[0089] In the following embodiments, normal pressure refers to a standard atmospheric pressure (about 0.1 MPa).

[0090] The contents of each component in the products in the following examples are obtained by area normalization method, and all contents are in mass percentage unless otherwise specified.

[0091] The conversion rate and selectivity of the target product involved in the following examples are calculated according to the following formula:

[0092] Formula 1 (calculation of the total conversion rate A of the first reaction):

[0093]

[0094] Formula 2 (calculation of the overall selectivity B of the second reaction):

[0095]

[0096] Formula 3 (calculation of the total conversion rate C of the second reaction):

[0097]

[0098] Formula 4 (calculation of the total selectivity D of the second reaction):

[0099]

[0100] Example 1

[0101] The synthesis method of 1-chloro-1,1-difluoro-2-iodoethane (CFIE for short) in this embodiment comprises the following steps:

[0102] (1) Synthesis of 3,3-difluoro-3-chloro-propionyl halide (first reaction)

[0103] In a 5L Hastelloy C-276 reactor (with stirring and jacket), add 3268g (about 15mol) of raw material 1 (of which the mass content of F232fa is 99.5%, and the mass content of F233fa is 0.5%), add 2384g (about 16.5mol) of raw material 2 (3-chloro-3,3-difluoropropionic acid molar content is more than 99.5%, and water content is less than 0.01 mol%). Add 120g (about 0.75mol) of catalyst (ferric oxide molar content ≥ 99.0%, AR). After nitrogen replacement, start stirring, increase the speed to 400rpm, pass silicone oil (preferably methyl silicone oil with a temperature range of -50 to 180°C) through the jacket, raise the temperature to 130°C, react for 4h, and exhaust the tail gas of the reactor through the condenser to reflux the reaction liquid, and control the pressure in the reactor at 0.1-0.3MPa until the reaction is completed. 5725 g of the reaction solution was harvested and analyzed by gas chromatography, with a content of 96.9% of 3,3-difluoro-3-chloro-propionyl chloride, 0.4% of 3,3-difluoro-3-chloro-propionyl fluoride, 1.7% of malonyl chloride and 1.0% of 2-fluoroacetyl chloride. After precise filtration (two-stage 1000-mesh metal sintered tube filtration), the solution was transferred to a Hastelloy C-276 distillation tower for distillation separation. The distillation (collecting the fraction with a boiling point of 48-57° C. under normal pressure) gave 99.4% of 3,3-difluoro-3-chloro-propionyl chloride and 0.4% of 3,3-difluoro-3-chloro-propionyl fluoride, totaling 5210 g. The total conversion rate (A) of raw material 1 and raw material 2 is 99.5%, and the total selectivity (B) of 3,3-difluoro-3-chloro-propionyl halide (ie, 3,3-difluoro-3-chloro-propionyl chloride and 3,3-difluoro-3-chloro-propionyl fluoride) is 93.2%.

[0104] (2) Synthesis of CFIE (Second Reaction)

[0105] In a 5L Hastelloy C-276 reactor (with stirring and jacket), add 3320g (about 20mol) of raw material 4 (KI, ≥99.5%, AR), and add 1790g of raw material 3 (the product obtained in step (1), wherein: the content of 3-chloro-3,3-difluoropropionyl chloride is 99.4%, and the content of 3,3-difluoro-3-chloro-propionyl fluoride is 0.4%, about 10mol). After sealing the reactor, start stirring, rotate at 300rpm, heat to 200℃, and react for 6h. The pressure in the reactor can reach 3.0MPa. After the reaction, the reactor was cooled to 100°C, the temperature in the reactor was maintained at 95-105°C, the pressure was slowly released, and the tail gas was collected by a condenser (refrigerant temperature -40°C, the refrigerant was an ethylene glycol aqueous solution with an ethylene glycol content of 44%, a freezing point of -100°C, and a use range of -60°C to 40°C), and a total of 1973.6g of product was obtained, of which the target product CFIE mass content was 82.3%, and the mass content of 3-chloro-3,3-difluoropropionyl chloride was 16.2%. After rectification, the fraction with a boiling point of 90-95°C under normal pressure was collected, and a CFIE content of more than 98.5% (different experimental batches had differences, but all were more than 98.5%) could be obtained. The total conversion rate (C) of the raw material 3 was calculated to be 66.8%, and the total selectivity (D) of CFIE was 99.5%.

[0106] Example 2-19 is basically the same as Example 1, except that: in the synthesis process of 3,3-difluoro-3-chloro-propionyl halide in step (1), some parameters and materials are selected differently, so that the total conversion rate (A) of raw material 1 and raw material 2 and the total selectivity (B) of 3,3-difluoro-3-chloro-propionyl halide (that is, 3,3-difluoro-3-chloro-propionyl chloride and 3,3-difluoro-3-chloro-propionyl fluoride) are different, and thus the total conversion rate (C) of raw material 3 and the total selectivity (D) of CFIE are different. The details are shown in Table 1.

[0107] Table 1 Partial parameter selection and material selection during the synthesis of 3,3-difluoro-3-chloro-propionyl halide in Example 1-19

[0108]

[0109] Examples 20-34 are basically the same as Example 1, except that: in step (2), some parameters and materials are selected differently during the synthesis of CFIE, resulting in different total conversion rates (C) of the raw material 3 and total selectivity (D) of CFIE. The details are shown in Table 2.

[0110] Table 2 Partial parameter selection, material selection and total conversion rate during the synthesis of Example 1, 20-34CFIE

[0111]

[0112]

[0113] Embodiment 35

[0114] This embodiment is basically the same as Embodiment 1, except that:

[0115] In step (1), the mass content of F232fa is 80.1%, and the mass content of F233fa is 19.9%; distillation (collecting the fraction with a boiling point of 48-57° C. under normal pressure) can obtain 81.7% of 3,3-difluoro-3-chloro-propionyl chloride and 18.2% of 3,3-difluoro-3-chloro-propionyl fluoride, totaling 5210 g; the total conversion rate (A) of raw materials 1 and raw materials 2 is 99.6%, and the total selectivity (B) of 3,3-difluoro-3-chloro-propionyl halide (i.e., 3,3-difluoro-3-chloro-propionyl chloride and 3,3-difluoro-3-chloro-propionyl fluoride) is 93.0%.

[0116] In step (2), 1790 g of raw material 3 (the product obtained in step (1), wherein the content of 3-chloro-3,3-difluoropropionyl chloride is 81.7%, the content of 3,3-difluoro-3-chloro-propionyl fluoride is 18.2%, about 10 mol) is added; the total conversion rate (C) of raw material 3 is calculated to be 69.3%, and the total selectivity of CFIE (D) is 99.3%.

[0117] Embodiment 36

[0118] This embodiment is basically the same as Embodiment 1, except that:

[0119] In step (1), the mass content of F232fa is 65.3%, and the mass content of F233fa is 34.7%; distillation (collecting the fraction with a boiling point of 48-57° C. under normal pressure) can obtain 61.2% of 3,3-difluoro-3-chloro-propionyl chloride and 38.5% of 3,3-difluoro-3-chloro-propionyl fluoride, totaling 5210 g; the total conversion rate (A) of raw materials 1 and raw materials 2 is 99.5%, and the total selectivity (B) of 3,3-difluoro-3-chloro-propionyl halide (i.e., 3,3-difluoro-3-chloro-propionyl chloride and 3,3-difluoro-3-chloro-propionyl fluoride) is 93.0%.

[0120] In step (2), 1790 g of raw material 3 (3-chloro-3,3-difluoropropionyl chloride obtained in step (1) with a content of 61.2% and 3,3-difluoro-3-chloro-propionyl fluoride with a content of 38.5%, about 10 mol) was added; the total conversion rate (C) of raw material 3 was calculated to be 67.5%, and the total CFIE selectivity (D) was 99.1%.

[0121] Embodiment 37

[0122] This embodiment is basically the same as Embodiment 1, except that:

[0123] In step (1), the mass content of F232fa is 44.3%, and the mass content of F233fa is 55.7%; distillation (collecting the fraction with a boiling point of 48-57° C. under normal pressure) can obtain 41.2% of 3,3-difluoro-3-chloro-propionyl chloride and 58.5% of 3,3-difluoro-3-chloro-propionyl fluoride, totaling 5210 g; the total conversion rate (A) of raw materials 1 and raw materials 2 is 99.0%, and the total selectivity (B) of 3,3-difluoro-3-chloro-propionyl halide (i.e., 3,3-difluoro-3-chloro-propionyl chloride and 3,3-difluoro-3-chloro-propionyl fluoride) is 93.8%.

[0124] In step (2), 1790 g of raw material 3 (the product obtained in step (1), wherein the content of 3-chloro-3,3-difluoropropionyl chloride is 41.2%, the content of 3,3-difluoro-3-chloro-propionyl fluoride is 58.5%, about 10 mol) is added; the total conversion rate (C) of raw material 3 is calculated to be 65.2%, and the total selectivity of CFIE (D) is 99.1%.

[0125] Embodiment 38

[0126] This embodiment is basically the same as embodiment 1, except that: in step (1), the synthesis of 3,3-difluoro-3-chloro-propionyl halide is divided into two parts, and the mixture of the products of the two parts is used as raw material 3 for the synthesis of CFIE in step (2).

[0127] Specific:

[0128] In step (1), the synthesis of the first part of 3,3-difluoro-3-chloro-propionyl halide is substantially the same as that in Example 1, except that: the mass content of F232fa is 30.1%, and the mass content of F233fa is 69.9%; distillation (collecting the fraction with a boiling point of 48-57° C. under normal pressure) can obtain 30.5% of 3,3-difluoro-3-chloro-propionyl chloride and 69.5% of 3,3-difluoro-3-chloro-propionyl fluoride, a total of 5210 g; the total conversion rate (A) of raw material 1 and raw material 2 is 99.5%, and the total selectivity (B) of 3,3-difluoro-3-chloro-propionyl halide (i.e., 3,3-difluoro-3-chloro-propionyl chloride and 3,3-difluoro-3-chloro-propionyl fluoride) is 93.7%.

[0129] In step (2), 1790 g of raw material 3 (the product obtained in step (1), wherein the content of 3-chloro-3,3-difluoropropionyl chloride is 30.5%, the content of 3,3-difluoro-3-chloro-propionyl fluoride is 69.5%, about 10 mol) is added; the total conversion rate (C) of raw material 3 is calculated to be 66.9%, and the total selectivity of CFIE (D) is 99.5%.

[0130] Embodiment 39

[0131] This embodiment is basically the same as Embodiment 1, except that:

[0132] In step (1), the mass content of F232fa is 1.2%, and the mass content of F233fa is 98.8%; distillation (collecting the fraction with a boiling point of 48-57° C. under normal pressure) can obtain 0.4% 3,3-difluoro-3-chloro-propionyl chloride and 99.5% 3,3-difluoro-3-chloro-propionyl fluoride, totaling 5210 g; the total conversion rate (A) of raw materials 1 and raw materials 2 is 99.1%, and the total selectivity (B) of 3,3-difluoro-3-chloro-propionyl halide (i.e. 3,3-difluoro-3-chloro-propionyl chloride and 3,3-difluoro-3-chloro-propionyl fluoride) is 93.3%.

[0133] In step (2), 1790 g of raw material 3 (the product obtained in step (1), wherein the content of 3-chloro-3,3-difluoropropionyl chloride is 0.4%, the content of 3,3-difluoro-3-chloro-propionyl fluoride is 99.5%, about 10 mol) is added; the total conversion rate (C) of raw material 3 is calculated to be 67.2%, and the total selectivity (D) of CFIE is 99.4%.

[0134] Example 40 (Compared with Example 1, the first reaction product is not distilled)

[0135] This embodiment is basically the same as Embodiment 1, except that:

[0136] In step (1), 5725 g of reaction liquid is harvested (gas chromatography analysis result: 3,3-difluoro-3-chloro-propionyl chloride content 96.9%, 3,3-difluoro-3-chloro-propionyl fluoride 0.4%, 1.7% of malonyl chloride, 1.0% of 2-fluoroacetyl chloride), and the product is directly filtered (two-stage 1000 mesh metal sintered tube filtration) without rectification to obtain synthetic raw material 3 that can be directly used as reaction 2; the total conversion rate (A) of raw material 1 and raw material 2 is 99.5%, and the total selectivity (B) of 3,3-difluoro-3-chloro-propionyl halide (i.e. 3,3-difluoro-3-chloro-propionyl chloride and 3,3-difluoro-3-chloro-propionyl fluoride) is 93.2%.

[0137] In step (2), 1790 g of raw material 3 (the product obtained in step (1), wherein: the content of 3,3-difluoro-3-chloro-propionyl chloride is 96.9%, the content of 3,3-difluoro-3-chloro-propionyl fluoride is 0.4%, about 10 mol) is added; the total conversion rate (C) of raw material 3 is calculated to be 67.0%, and the total selectivity of CFIE (D) is 99.4%.

[0138] Embodiment 41

[0139] This example describes a full-process synthesis of a certain scale of synthetic CFEI, the steps are as follows:

[0140] (1) Synthesis of 3,3-difluoro-3-chloro-propionyl halide (first reaction)

[0141] In a 200L Hastelloy C-276 reactor (with stirring and jacket), add 130.5kg (about 600mol) of raw material 1 (of which the mass content of F232fa is 99.5% and the mass content of F233fa is 0.5%), add 96.0kg (about 660mol) of raw material 2 (3-chloro-3,3-difluoropropionic acid molar content is more than 99.5%, water content <0.01 mol%). Add 4.8kg (about 30mol) of catalyst (ferric oxide molar content ≥99.0%, AR). After nitrogen replacement, start stirring, increase the speed to 400rpm, pass steam into the jacket, raise the temperature to 110℃, stop heating, the reaction exothermic reaction causes the reactants to continue to heat up, and then start to intermittently pass cooling water into the reactor to control the temperature in the reactor at 125-130℃. At this time, the reaction timer was started, and the reaction tail gas was refluxed through the condenser to exhaust the reaction liquid intermittently, and the pressure in the reactor was controlled at 0.1-0.3MPa. After 6.5 hours of reaction, the pressure in the reactor no longer changed, the temperature in the reactor could not be maintained, and the reaction was stopped. The reaction liquid was cooled to 10° C., and the reaction liquid was discharged after nitrogen bubbling replacement. 230 kg of the reaction liquid was harvested. After gas chromatography analysis, the content of 3,3-difluoro-3-chloro-propionyl chloride was 97.0%, 3,3-difluoro-3-chloro-propionyl fluoride was 0.9%, 1.3% of malonyl chloride, and 0.8% of 2-fluoroacetyl chloride. After precision filtration (two-stage 1000-mesh metal sintered tube filtration), the reaction liquid was transferred to a Hastelloy C-276 distillation tower (distillation tower kettle 300 L, tower body height 10 m, tower diameter 200 mm) for distillation separation. The distillation (collecting the fraction with a boiling point of 55-57° C. under normal pressure) can obtain 3,3-difluoro-3-chloro-propionyl chloride with a content of 99.5% and 3,3-difluoro-3-chloro-propionyl fluoride with a content of 0.48%, totaling 209.2 g. The total conversion rate (A) of raw materials 1 and 2 is 99.6%, and the total selectivity (B) of 3,3-difluoro-3-chloro-propionyl halide (i.e., 3,3-difluoro-3-chloro-propionyl chloride and 3,3-difluoro-3-chloro-propionyl fluoride) is 93.9%. The raw material 2, 3-chloro-3,3-difluoropropionic acid, can be obtained by hydrolyzing a part of 3,3-difluoro-3-chloro-propionyl chloride.

[0142] (2) Synthesis of CFIE (Second Reaction)

[0143] In a 200L Hastelloy C-276 reactor (with stirring and jacket), add 132.5kg (about 800mol) of raw material 4 (KI, ≥99.5%) and 72.0kg of raw material 3 (the product obtained in step (1), wherein: 3-chloro-3,3-difluoropropionyl chloride has a mass content of 99.4%, and 3,3-difluoro-3-chloro-propionyl fluoride has a content of 0.31%, about 400mol). After sealing the reactor, start stirring, rotate at 300rpm, heat to 200℃, and react for 6h. The pressure in the reactor can reach 3.0MPa. After the reaction, the reactor was cooled to 100°C, maintained at 105-110°C, and the pressure was slowly released. The tail gas was collected by a condenser (refrigerant temperature -40°C, and the refrigerant was dimethyl silicone oil) to obtain a total of 79.0 kg of products, of which the target product CFIE had a mass content of 83.5%, and the mass content of 3-chloro-3,3-difluoropropionyl chloride was 15.9%. After rectification, the fraction with a boiling point of 90-95°C under normal pressure was collected to obtain CFIE with a content of 99.0% (a total of 66 kg), which can be used for the synthesis of 1,1-difluoro-2-iodoethylene. The total conversion rate (C) of the raw material 3 was calculated to be 67.1%, and the total selectivity of CFIE was 99.5%.

[0144] Comparative Example

[0145] The synthesis method of 1-chloro-1,1-difluoro-2-iodoethane (abbreviated as CFIE) in this comparative example is the addition synthesis of iodine chloride and vinylidene fluoride. Specifically, 2 kg (12.3 mol) of iodine monochloride was added to a 5L reactor, and the reactor was cooled to 5°C and replaced with nitrogen for 5 times, and then replaced with raw material gas vinylidene fluoride (VDF) for 2 times, and then the reactor was heated to 30°C, VDF was introduced into the iodine monochloride for reaction, and when the molar ratio of the introduced VDF to the iodine monochloride was 2:1, the introduction of VDF was stopped, the reaction was continued for 12 hours, and the reaction was terminated, the reactor was cooled to room temperature, and the unreacted vinylidene fluoride was replaced with nitrogen, 5 wt% of sodium hydroxide aqueous solution and 5 wt% of sodium bisulfite aqueous solution were added to the reaction solution, and stirred at 300 rpm for 20 minutes, the obtained mixed solution was allowed to stand for stratification, and the lower organic phase was separated, and the organic phase was purified by distillation to obtain 1-chloro-1,1-difluoro-2-iodoethane with a purity of 98%, and the selectivity based on iodine monochloride was 98.5%, and the yield was 95%.

[0146] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0147] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0148] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for synthesizing ethane halides, characterized in that: include: The halogenated propane is first reacted with the halogenated propionic acid under the action of a catalyst to obtain a propionyl halide compound; The propionyl halide compound is subjected to a second reaction with an alkali metal halide salt to obtain the halogenated ethane.

2. The synthesis method according to claim 1, characterized in that The halogenated propane includes at least one of 1,1,1,3-tetrachloro-3,3-difluoropropane and 1,1,3-trichloro-1,3,3-trifluoropropane; preferably, the 1,1,1,3-tetrachloro-3,3-difluoropropane and 1,1,3-trichloro-1,3,3-trifluoropropane are intermediates in the production process of 1,1,1,3,3,3-hexafluoropropane.

3. The synthesis method according to claim 1, characterized in that The catalyst comprises a metal oxide; and / or, The halogenated propionic acid is 3-chloro-3,3-difluoropropionic acid.

4. The synthesis method according to claim 3, characterized in that The metal oxide includes at least one of ferric oxide, ferroferric oxide, aluminum oxide, nickel oxide, and titanium oxide; and / or, The halogenated propionic acid is 3-chloro-3,3-difluoropropionic acid.

5. The synthesis method according to claim 1, characterized in that The propionyl halide compound includes 3,3-difluoro-3-chloro-propionyl halide; and / or, The alkali metal halide salt includes at least one of anhydrous sodium iodide, anhydrous potassium iodide, anhydrous lithium iodide, and anhydrous cesium iodide; and / or, The halogenated ethane includes 1-chloro-1,1-difluoro-2-iodoethane.

6. The synthesis method according to claim 1, characterized in that The first reaction is an oxidation reaction; and / or, The temperature of the first reaction is 110-140° C.; and / or, The first reaction time is 2-6 hours; and / or, The absolute pressure of the first reaction is 0.1-0.3 MPa.

7. The synthesis method according to claim 1, characterized in that The reaction temperature of the second reaction is 150-300° C.; and / or, The reaction time of the second reaction is 3-9h; and / or, The absolute pressure of the second reaction is 1.5-4.5 MPa.

8. The synthesis method according to claim 1, characterized in that The molar ratio of the halopropionic acid to the halopropane is (0.95-1.2):

1.

9. The synthesis method according to claim 1, characterized in that The molar ratio of the catalyst to the halogenated propane is 1:(10-30).

10. The synthesis method according to claim 1, characterized in that The molar ratio of the alkali metal halide salt to the propionyl halide compound is (1.5-2.5):1.

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