Uses of 1,1,2-trichloro-2-fluoroethene (TCFE)

Abstract

To provide a novel method capable of efficiently producing 1,1,2-trichloro-2-fluoroethene (TCFE) and to provide a novel application for TCFE.SOLUTION: There are provided: a method for producing 1,1,2-trichloro-2-fluoroethene (TCFE) which comprises (a) a step of fluorinating pentachloroethane at a temperature of 0 to 80°C to generate monofluoropentachloroethane and (b) a step of reacting the monofluoropentachloroethane obtained in the step (a) with zinc to generate TCFE; and a use of a composition comprising TCFE as a solvent or a detergent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a novel method for producing 1,1,2-trichloro-2-fluoroethene (hereinafter referred to as TCFE or "trichloromonofluoroethene") and a novel use thereof. [Background technology]

[0002] TCFE is a known substance (CAS No. 359-29-5), but no clear application has been found to date. Because the usefulness of TCFE has not been discovered, an efficient method for synthesizing TCFE has not been developed. Summary of the Invention [Problem to be solved by the invention]

[0003] An object of the present invention is to provide a novel method for efficiently producing TCFE. Another object of the present invention is to provide a novel use of TCFE. [Means for solving the problem]

[0004] The present invention provides the following: [1] A method for producing 1,1,2-trichloro-2-fluoroethene (TCFE), comprising the steps of: (a) fluorinating pentachloroethane at a temperature between 0 and 80°C to produce monofluoropentachloroethane; and (b) The monofluoropentachloroethane obtained in (a) is reacted with zinc to produce TCFE. A method comprising the steps of: [2] The method according to [1], wherein the fluorination (a) is carried out using a mixture of F2 gas and an inert gas having an F2 gas concentration of 1 to 100% by volume. [3] The method according to [1] or [2], wherein the fluorination of (a) is carried out in a solvent. [4] The method according to any one of [1] to [3], wherein the reaction (b) is carried out at a temperature of −50 to 120° C. [5] The method according to any one of [1] to [4], wherein the reaction (b) is carried out in a solvent. [6] The method according to any one of [1] to [5], wherein pentachloroethane used in (a) is obtained by chlorinating trichloroethene (TCE). [7] Use of a composition comprising 1,1,2-trichloro-2-fluoroethene (TCFE) as a solvent or cleaning agent. [8] Use of a composition containing the TCFE described in [7] as a cleaning agent for cleaning flux or processing oil. [9] A method for removing contaminants from a substrate, comprising contacting the substrate with a composition comprising a TCFE.

[10] [9] The method according to [9], wherein the contaminant is a flux or a processing oil. [Effects of the Invention]

[0005] The present invention provides a novel production method capable of efficiently producing TCFE from pentachloroethane via monofluoropentachloroethane. According to the present invention, the process of fluorinating pentachloroethane to obtain monofluoropentachloroethane can be carried out with nearly 100% conversion and 95% or higher selectivity. Furthermore, the process of obtaining TCFE from monofluoropentachloroethane can be carried out with a conversion and selectivity exceeding 99%. Therefore, by combining this process with a conventional method for obtaining pentachloroethane in high yield by chlorinating trichloroethene (TCE), the target TCFE can be obtained in a yield of 90% or higher from readily available TCE. Since each process has a conversion of 99% or higher and a selectivity of 95% or higher, it is not necessary to isolate and purify the product before use in the next process, resulting in extremely high operational efficiency. The present invention also provides new uses for TCFE, particularly its use as a solvent or cleaning agent. DETAILED DESCRIPTION OF THE INVENTION

[0006] [Effect] Conventionally, the process of fluorinating pentachloroethane to obtain monofluoropentachloroethane has been thought to have poor reaction efficiency and should be carried out at a high reaction temperature of around 90°C. However, the present inventors unexpectedly discovered that by carrying out the process at a low temperature of around 20°C, side reactions do not occur, the yield (conversion rate and selectivity) is improved, and monofluoropentachloroethane can be obtained in high yield. In the present invention, the reaction conditions were examined and the process of obtaining TCFE from monofluoropentachloroethane was also successfully carried out in high yield. Therefore, according to the present invention, TCFE can be obtained in a yield of 90% or more from easily available TCE via pentachloroethane and monofluoropentachloroethane.

[0007] According to the present invention, it has been unexpectedly discovered that TCFE is useful as a solvent, a cleaning agent, etc. Since TCFE has a boiling point of 71°C, it can be easily dried, and it has also been found that TCFE is suitable for use as a cleaning agent.

[0008] [TCFE manufacturing method] The present invention provides a method for producing 1,1,2-trichloro-2-fluoroethene (TCFE), comprising the steps of: (a) fluorinating pentachloroethane at a temperature between 0 and 80°C to produce monofluoropentachloroethane; and (b) The monofluoropentachloroethane obtained in (a) is reacted with zinc to produce TCFE. The present invention is characterized in that the fluorination reaction in step (a) is carried out at 0 to 80°C, particularly 10 to 30°C, and the dechlorination reaction in step (b) is carried out using zinc. By adopting such reaction conditions, the yield in step (a) and the yield in step (b) can both be carried out with a conversion of 99% or more and a selectivity of 95% or more, and therefore the reaction solution can be used as the raw material for the next step without purifying or isolating the product between each step.

[0009] The fluorination in step (a) can be carried out using a mixture of F2 gas with an F2 gas concentration of 1 to 100% by volume, particularly 20 to 50% by volume, and an inert gas, such as nitrogen (N2) gas or a rare gas such as He, Ne, Ar, or Xe.

[0010] The steps (a) and (b) are carried out in a solvent that does not react with the fluorinating agent or zinc, such as carbon tetrachloride, perfluorocarbons (PFCs), hydrofluorocarbons (HFCs), hydrochlorides, etc. The reaction can be carried out as a liquid phase reaction using organic solvents such as monofluorocarbons (HCFCs), chlorofluorocarbons (CFCs), perfluoroethers (PFEs), hydrofluoroethers (HFEs), methanol, ethanol, 2-methoxyethanol, diglyme, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, and acetonitrile. The melting point of the product of step (a) (monofluoropentachloroethane) is 101°C. Therefore, if no organic solvent is used, the product will exist as a solid in the reaction vessel at the reaction temperature of step (a). Furthermore, if step (b) is carried out at temperatures below 101°C, it is preferable to use an organic solvent to prepare the raw materials for step (b) in solution. In particular, 2-methoxyethanol has a boiling point of 124°C, so it does not readily evaporate at room temperature, but it can be separated from the product by either reduced-pressure or atmospheric distillation.

[0011] The reaction in step (b) is preferably carried out at a temperature of -50 to 120°C, particularly -50 to 100°C, and particularly -20 to 80°C. Furthermore, it is desirable that the zinc used in step (b) be in the form of granules or powder, from the viewpoints of reaction efficiency and ease of handling. When the solvents used in steps (a) and (b) are different, solvent substitution is required. This solvent substitution can be carried out, for example, by removing the solvent used in step (a) from the reaction vessel by distillation and adding the solvent used in step (b) to the reaction vessel.

[0012] Pentachloroethane used in step (a) can be obtained, for example, by chlorinating trichloroethene (TCE). The chlorination reaction of TCE is well known in the art, and can provide the raw material for step (a) in high yield.

[0013] [Uses of TCFE] According to the present invention, new uses of TCFE as a solvent and cleaning agent have been discovered. TCFE can be mixed in any ratio with organic solvents, such as ketones (e.g., acetone, acetophenone), nitriles (e.g., acetonitrile, propionitrile), ethers (e.g., diisopropyl ether, t-butyl methyl ether, tetrahydrofuran, diglyme, 1,4-dioxane), sulfoxides (e.g., dimethyl sulfoxide, sulfolane), amides (e.g., dimethylformamide, dimethylacetamide, N-methylpyrrolidone), hydrocarbons (e.g., hexane, heptane, cyclohexane, benzene, toluene), and alcohols (e.g., methanol, ethanol, isopropyl alcohol). Therefore, TCFE can be used in a wide range of applications as a mixed solvent. Furthermore, TCFE has excellent oil solubility, making it suitable for use as a cleaning agent. TCFE's boiling point of 71°C allows for good drying, making it suitable for use as a cleaning agent. [Example]

[0014] The present invention will be described by the following examples, but the scope of the present invention is not limited to these examples.

[0015] TCFE was produced from TCE according to the following reaction process. [ka] (In the above reaction formula, "rt" means room temperature, and "M" means the molar concentration of the reaction substrate (mol / L), "h" means time, and the concentration of F2 gas is in volume %.

[0016] [Example 1] First step (TCE → C2Cl5H) 500 g (3.8 mol) of TCE was weighed into a 500 mL three-necked glass flask. After replacing the atmosphere with nitrogen, the reaction mixture was cooled in an ice bath. Cl2 was then introduced at 180 mL / min while stirring. After introducing 1.0 equivalent (270 g, 3.8 mol) of Cl2, nitrogen was introduced to expel any remaining Cl2 in the mixture. As a result, 723 g (99% yield) of the target pentachloroethane was obtained as a colorless, transparent liquid with a GC purity of 97.9%.

[0017] [Example 2] Second step (C2Cl5H → C2Cl5F) A 5 L PFA (perfluoroalkoxyalkane resin) reactor equipped with a condenser was charged with 700 g (3.5 mol) of pentachloroethane and 3 L of CCl4. The reactor was purged with nitrogen, and the reaction temperature was adjusted to 20 °C using a water bath. The nitrogen flow was then stopped, and a 20 vol% F2 / N2 gas mixture (vol% concentration in the N2 gas mixture) was introduced at 110 mL / min for 91 hours (1.55 equivalents). After the introduction of F2 was completed, the temperature was raised to room temperature under nitrogen flow. The resulting reaction solution was washed with 10 mL of 5 wt% aqueous sodium bicarbonate and analyzed by GC, revealing a conversion of 99% and a selectivity of 97%.

[0018] As shown in Table 1 below, the inventors have discovered that in the second step, the reaction from C2Cl5H to C2Cl5F, the selectivity of the product increases in a specific temperature range by changing the reaction conditions and performing the reaction multiple times on a small scale (at temperatures above 80°C, perchloroethene (PCE) is the main by-product, and at temperatures below 0°C, the reaction hardly proceeds). Note that because C2Cl5F is a solid, the introduction of F2 gas is stopped after 0.5 equivalents when no solvent is used and the temperature is below its melting point (101°C).

[0019] [Table 1] (Footnote) *Both conversion and selectivity were determined from the area percentage of GC analysis.

[0020] The data for the product of step 2, C2Cl5F, is shown below. [ka] Appearance: White solid 19 FNMR(CDCl3):-62.9(s,1F) 13 CNMR(CDCl3):101.0(d,J=34Hz),122.0(d,J=309)

[0021] [Example 3] Third step (C2Cl5F → TCFE) A 2L glass three-necked flask equipped with a Dimroth condenser and a dropping funnel was charged with 291g (1.1 equivalents) of Zn powder and 200mL of 2-methoxyethanol, and the reactor was immersed in an ice bath. Then, 809g of C2Cl5F dissolved in 740mL of 2-methoxyethanol was charged into the dropping funnel. The C2Cl5F solution was then added dropwise over 5 hours, the temperature was raised to room temperature, and the mixture was stirred for a further 12 hours. As a result, a conversion rate of 99% and a selectivity of 99% ( 19 The reaction was judged to be complete when the temperature reached 100°C (determined by F NMR). The dropping funnel and Dimroth condenser were removed from the reactor, and a simple distillation apparatus was assembled. The temperature of the oil bath was gradually increased from 80°C to 120°C under normal pressure, and this was continued until no more distillate was produced. As a result, 431 g of TCFE crude product was obtained as a colorless, transparent liquid. The TCFE crude product was then purified by rectification. The components at the top of the column at 71°C were collected, and 361.3 g of TCFE with a GC purity of 99% or more was obtained.

[0022] The data for TCFE, the product of step 3, is shown below. [ka] Appearance: Colorless transparent liquid 19 F NMR(CDCl3): -78.6(s, 1F) 13 C NMR(CDCl3):107.5(d,J=44Hz),143.2(d,J=302Hz) Boiling point: 71℃ Density: 1.5271 (25℃)

[0023] [Cleaning power evaluation test] The solubility (cleaning ability) of each evaluation target in TCFE is shown in Table 2. The values ​​in the table indicate the number of grams of each evaluation target that dissolves in 100 g of solvent. "Compatible" means that 100 g of the evaluation target dissolved in 100 g of solvent.

[0024] [Table 2] *1: Reference material: Development of cleaning technology, CMC Publishing *2: Zeorora (registered trademark) HTA, AE-3000, and AK-225 are all product names of cleaning agents. *3:1233Z is an abbreviation for cis-1-chloro-3,3,3-trifluoropropene.

[0025] As can be seen from Table 2 above, TCFE was mixed in any ratio with the punching oil, cutting oil, and natural oil (vegetable oil) tested, and abietic acid, the main component of the flux, showed 40 to 150 times the solubility of existing fluorine-based cleaners. In other words, it was found to have cleaning power.

Claims

1. Use of a composition comprising 1,1,2-trichloro-2-fluoroethene (TCFE) as a cleaning agent for cleaning flux, wherein the flux comprises abietic acid.

2. A method for removing contaminants from a substrate, the method comprising contacting the substrate with a composition comprising 1,1,2-trichloro-2-fluoroethene (TCFE), wherein the contaminants are a flux comprising abietic acid.

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