Composition containing fluoroethylene, and method for stabilizing the composition

Abstract

To provide a composition containing fluoroethylene with suppressed production of acid.SOLUTION: A composition comprises a refrigerant and an antioxidant, wherein the refrigerant contains fluoroethylene, the contained amount of the antioxidant is 1-20000 mass ppm with respect to the mass of the fluoroethylene, and the total mass of the refrigerant and the antioxidant is 95 mass% or more with respect to 100 mass% of the entire composition.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a composition containing fluoroethylene and a method for stabilizing the composition.

Background Art

[0002] Fluoroethylene, including trans-1,2-difluoroethylene (hereinafter also simply referred to as "HFO-1132(E)"), is used in various applications including heat transfer media, and its demand is expected to increase in the future.

[0003] Various methods have been studied as methods for suppressing the generation of hydrogen fluoride in a composition containing fluoroethylene. Patent Documents 1 and 2 disclose methods of containing an acid scavenger or an antioxidant in the composition.

[0004] Also, Patent Documents 3 to 5 disclose methods of restricting the amount of oxygen contained in the composition or containing a remover for removing oxygen in the composition.

Prior Art Documents

Patent Documents

[0007] The Disclosers conducted extensive research to solve the above-mentioned problems and found that by including an antioxidant, the formation of acid in compositions containing fluoroethylene can be suppressed. Based on this finding, the Disclosers conducted further research and completed this disclosure.

[0008] In other words, this disclosure provides compositions comprising the following fluoroethylenes and methods for stabilizing said compositions. Section 1. Includes refrigerant and antioxidant, The aforementioned refrigerant includes fluoroethylene, A composition in which the content of the antioxidant is 1 to 20,000 ppm by mass based on the mass of the fluoroethylene, and the total mass of the refrigerant and the antioxidant is 95% by mass or more of 100% by mass of the entire composition. Section 2. The composition according to item 1, wherein the content of refrigerant oil is 0 to 30,000 ppm by mass based on the mass of fluoroethylene. Section 3. The aforementioned antioxidant is selected from the group consisting of phenols, alkylcatechols, benzoquinones, phenothiazines, terpenes, terpenoids, and phthalates. A composition according to item 1 or 2, which is at least one of the following. Section 4. The composition according to claim 3, wherein the antioxidant is at least one selected from the group consisting of dibutylhydroxytoluene, myrcene, pinene, and limonene. Section 5. The composition according to any one of items 1 to 4, further containing oxygen, wherein the oxygen content is 5000 ppm by mass or less based on the mass of the fluoroethylene. Section 6. The process includes a step of obtaining a composition by having a refrigerant and an antioxidant coexist, The aforementioned refrigerant includes fluoroethylene, The content of the antioxidant is 1 to 20,000 ppm by mass, based on the mass of the fluoroethylene. A method for stabilizing a composition containing fluoroethylene, wherein the total mass of the refrigerant and the antioxidant is 95% by mass or more of 100% by mass of the entire composition. Section 7. The method according to claim 6, wherein the antioxidant is at least one selected from the group consisting of dibutylhydroxytoluene and terpenes. [Effects of the Invention]

[0009] The composition according to the present disclosure, as described above, contains fluoroethylene while suppressing the formation of acid. [Modes for carrying out the invention]

[0010] In this specification, "contains" is a concept that encompasses all of the following: "contains," "consist essentially of," and "consist of." Furthermore, in this specification, when a numerical range is indicated as "A~B," it means A or greater and B or less.

[0011] (1. Composition containing fluoroethylene) The composition of the present disclosure contains a refrigerant and an antioxidant. The refrigerant contains fluoroethylene. The content of the antioxidant is 1 to 20,000 mass ppm based on the mass of the fluoroethylene, and the total mass of the fluoroethylene, the antioxidant, and components having the functions of other refrigerants is 95 mass% or more of the total mass of the refrigerant and the antioxidant. The proportion of the total mass of the fluoroethylene, the antioxidant, and components having the functions of other refrigerants in the whole composition is preferably 97 mass% or more, and more preferably 99 mass% or more. There is no particular limitation on the upper limit value of the total mass of the refrigerant and the antioxidant. For example, it is preferably 100 mass% in 100 mass% of the whole composition, and more preferably 99.9 mass%.

[0012] In addition, in this specification, the refrigerant at least includes a compound with a refrigerant number starting with R (ASHRAE number) defined by ISO817 (International Organization for Standardization) to represent the type of refrigerant, and further even if no refrigerant number has been assigned yet, those having characteristics equivalent to those of such refrigerants are included. Refrigerants are roughly classified into "fluorocarbon compounds" and "non-fluorocarbon compounds" in terms of the structure of the compounds. "Fluorocarbon compounds" include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). [[ID=IO]]

[0013] A composition containing fluoroethylene may gradually decompose due to the presence of coexisting oxygen in a long-term use environment or a storage environment to generate hydrogen fluoride. As a result, if hydrogen fluoride mixes into the composition containing fluoroethylene, it may cause factors to damage the equipment. There is a possibility.

[0014] As the fluoroethylene, known fluoroethylenes can be widely adopted without particular limitation. Any of trifluoroethylene, difluoroethylene, and monofluoroethylene can be preferably used. Among these, trans-1,2-difluoroethylene (HFO-1132(E)), cis-1,2-difluoroethylene (HFO-1132(Z)), 1,1,2-trifluoroethylene (HFO-1123), and fluoroethylene (HFO-1141) are preferably used and it is particularly preferable to use HFO-1132(E).

[0015] The content of the refrigeration oil in the composition of the present disclosure is preferably 30,000 mass ppm or less, more preferably 10,000 mass ppm or less, still more preferably 5,000 mass ppm or less, and most preferably not contained at all (0 mass ppm), based on the mass of the fluoroethylene. When the content of the refrigeration oil is 30,000 mass ppm or less based on the mass of the fluoroethylene, hydrogen fluoride in the composition is less likely to be generated, and deterioration associated with the acidification of the composition can be suppressed.

[0016] Antioxidants can be widely used from known antioxidants used in the art without particular limitation. Specifically, antioxidants such as phenols, alkyl catechols, benzoquinones, phenothiazines, terpenes, terpenoids, and phthalates, which are presumed to have the effect of capturing radicals and suppressing decomposition reactions, can be used. Among them, it is preferable to use phenols such as dibutylhydroxytoluene (also known as butylated hydroxytoluene; hereinafter also simply referred to as BHT), hydroquinone, or terpenes such as myrcene, pinene, and limonene.

[0017] The antioxidant content is 1 ppm by mass or more, preferably 10 ppm by mass or more, and more preferably 100 ppm by mass or more, based on the mass of fluoroethylene. By having an antioxidant content of 1 ppm by mass or more based on the mass of fluoroethylene, the decomposition of fluoroethylene and the generation of acid can be suppressed.

[0018] Furthermore, the antioxidant content is 20,000 ppm by mass or less, preferably 10,000 ppm by mass or less, and more preferably 2,000 ppm by mass or less, based on the mass of fluoroethylene. By keeping the antioxidant content at 20,000 ppm by mass or less, based on the mass of fluoroethylene, it is possible to avoid adding unnecessary amounts of antioxidant.

[0019] Furthermore, the content of fluoroethylene and antioxidants in the composition disclosed herein can be determined by sampling a certain amount of the fluoroethylene liquid phase and measuring the antioxidant content contained therein using analytical methods such as gas chromatography or NMR. If the antioxidant is solid and cannot be measured by the aforementioned analytical methods, the content can be calculated by evaporating the sampled liquid phase and measuring the weight of the antioxidant residue.

[0020] The compositions of this disclosure may further contain oxygen. The oxygen content is preferably 5,000 ppm by mass or less, more preferably 3,000 ppm by mass or less, and even more preferably 1,000 ppm by mass or less, based on the mass of fluoroethylene. By limiting the oxygen content of the compositions of this disclosure to 5,000 ppm by mass or less, based on the mass of fluoroethylene, the decomposition or polymerization reaction of fluoroethylene is suppressed, and the generation of hydrogen fluoride in the composition is suppressed, thereby reducing the deterioration of the composition.

[0021] The oxygen content in the compositions of this disclosure is determined by a commercially available gas chromatograph or oxygen concentration meter. By measuring the oxygen content in the gas phase and converting this measurement to determine the oxygen content in the liquid phase, the oxygen content can be quantified.

[0022] The compositions disclosed herein may further contain water.

[0023] Furthermore, the water content in the composition of this disclosure is preferably 100 ppm by mass or less, more preferably 50 ppm by mass or less, and even more preferably 20 ppm by mass or less, based on the mass of fluoroethylene. By limiting the water content to 100 ppm by mass or less based on the mass of fluoroethylene, the generation of solids due to side reactions, etc., can be suppressed, and the stability of the composition can be ensured.

[0024] The water content in the compositions of this disclosure can be measured using a commercially available Karl Fischer moisture analyzer, and the detection limit is typically 0.1 ppm by mass.

[0025] The compositions of this disclosure may contain additional compounds other than those described above, to the extent that they do not impair their effects or purposes. Examples of additional compounds include hydrogen fluoride, 1,1,1-trifluoroethane, propylene, acetylene, difluoromethane, trifluoromethane, fluoromethane, 1,1,2-trifluoroethylene (HFO-1123), 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 1,1,2-trifluoroethane (HFC-143), 2-chloro-1,1,1-trifluoroethane (HCFC-133b), 1-chloro-1,1,2-trifluoroethane (HCFC-133), 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123), 1-chloro-1,2-difluoroethane (HCFC-142a), and 1,2-difluoroethane. At least one substance can be selected from the group consisting of tan (HFC-152), chlorodifluoromethane (HCFC-22), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2-tetrafluoroethane (HFC-134), pentafluoroethane (HFC-125), 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,2,3,3,3-pentafluoropropene (HFO-1225ye), 1,3,3,3-tetrafluoropropene (HFO-1234ze), 1,3,3,3-tetrafluoropropene (HFO-1234ze), 3,3,3-trifluoropropene (HFO-1243zf), and ethylene, etc.

[0026] If the composition of the present disclosure contains the additional compound, its content is not particularly limited, but it is preferable that the additional compound is present in an amount of 0.1 ppm by mass or more and 10,000 ppm by mass or less, based on the mass of fluoroethylene.

[0027] When the compositions of this disclosure are used as a heat transfer medium, they may further contain components that have the function of a refrigerant in addition to fluoroethylene. Examples of such components include 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO-1234ze), 1,1,2-trifluoroethylene (HFO-1123), 1,1-difluoroethylene (HFO-1132a), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), difluoromethane (HFC-32), iodotrifluoromethane, carbon dioxide, propane, butane, and isobutane. When the composition of the present disclosure contains these components, with the total amount of the components having the function of a coolant being 100% by mass, the content of the other components is preferably 3 to 97% by mass in total, and more preferably 30 to 90% by mass.

[0028] When the composition of this disclosure is used as a heat transfer medium, it may further contain a lubricating oil. Such lubricating oil is not particularly limited, and for example, known lubricating oils used as refrigerants, etc. It can be widely adopted.

[0029] Specific lubricants include one or more selected from the group consisting of polyalkylene glycol, polyol ester, and polyvinyl ether. Examples of polyalkylene glycol (PAG) include "SUNICEP56" manufactured by Nippon Sun Oil Co., Ltd. Examples of polyol ester (POE) include "Ze-GLESRB32" manufactured by ENEOS Corporation. Examples of polyvinyl ether (PVE) include "Daphne Hermetic Oil FVC-D Series" manufactured by Idemitsu Kosan Co., Ltd.

[0030] The lubricating oil may further contain additives. The additives may be at least one selected from the group consisting of extreme pressure agents, acid scavengers, oxygen scavengers, copper deactivators, rust inhibitors, oiliness agents, and defoaming agents.

[0031] The compositions of this disclosure may further contain other additives or elements or compounds that are inevitably present (hereinafter referred to as "other components"). If the compositions of this disclosure contain other components, the content of the other components may be 5% by mass or less, preferably 1% by mass or less, more preferably 0.1% by mass or less, and particularly preferably 0.05% by mass or less, relative to the mass of fluoroethylene.

[0032] The method for preparing the compositions of this disclosure is not particularly limited. For example, they can be prepared by mixing fluoroethylene and an antioxidant in a predetermined ratio. In this mixture, the aforementioned lubricating oil and / or other additives may be added as appropriate. Furthermore, the amount of oxygen in the composition can be adjusted to a desired range by blowing air or oxygen into the composition.

[0033] In the production of fluoroethylene, if water and oxygen are present in the fluoroethylene, the fluoroethylene containing water and oxygen can be used as is in the composition of this disclosure. In this case, it is also possible to adjust the water content in the composition by adding or removing water. A wide range of known methods can be used to remove water, for example, by drying using an adsorbent.

[0034] In the manufacture of the compositions of this disclosure, the other components may be present in the compositions of this disclosure. However, the other components may be removed in advance by appropriate means before preparing the compositions, or they may be used in the compositions as they are without removal.

[0035] The compositions disclosed herein can be used in a variety of applications, including as heat transfer media, foaming agents, solvents, cleaning agents, propellants, and fire extinguishing agents. Such heat transfer media, foaming agents, solvents, cleaning agents, propellants, and fire extinguishing agents maintain their quality over a long period of time because the generation of hydrogen fluoride is suppressed and degradation is reduced.

[0036] (2. Method for stabilizing compositions containing fluoroethylene) This disclosure encompasses inventions relating to methods for stabilizing compositions containing fluoroethylene.

[0037] The method for stabilizing a composition containing fluoroethylene according to this disclosure includes the step of obtaining a composition by coexisting a refrigerant containing fluoroethylene and an antioxidant. Here, the content of the antioxidant in the composition is 1 to 20,000 ppm by mass based on the mass of the fluoroethylene. Furthermore, the total mass of the refrigerant and the antioxidant is 95% by mass or more of the total mass of the composition. There are no particular limitations on the method of coexisting these; for example, they may be mixed. The fluoroethylene, the antioxidant and other refrigerants have functions The total mass of the components is preferably 97% by mass or more, and more preferably 99% by mass or more, of the total mass of the components. There is no particular upper limit to the total mass of the refrigerant and antioxidant; for example, it is preferably 100% by mass out of 100% by mass of the total composition, and more preferably 99.9% by mass.

[0038] Fluoroethylene can be used in the same way as described above.

[0039] The amount of antioxidant added is 1 ppm by mass or more, preferably 10 ppm by mass or more, and more preferably 100 ppm by mass or more, based on the mass of fluoroethylene. By setting the amount of antioxidant to 1 ppm by mass or more, based on the mass of fluoroethylene, the decomposition of fluoroethylene and the generation of acid can be suppressed.

[0040] Furthermore, the amount of antioxidant added is 20,000 ppm by mass or less, preferably 10,000 ppm by mass or less, and more preferably 2,000 ppm by mass or less, based on the mass of fluoroethylene. By limiting the amount of antioxidant to 20,000 ppm by mass or less, based on the mass of fluoroethylene, it is possible to avoid adding unnecessary amounts of antioxidant.

[0041] It is preferable that the system containing the antioxidant and fluoroethylene contains substantially no refrigeration oil. The refrigeration oil content is preferably 30,000 ppm by mass or less, more preferably 5,000 ppm by mass or less, even more preferably 1,000 ppm by mass or less, and most preferably none at all (0 ppm by mass), based on the mass of fluoroethylene. By limiting the refrigeration oil content to 30,000 ppm by mass or less based on the mass of fluoroethylene, the generation of hydrogen fluoride in the system can be suppressed, and the deterioration of fluoroethylene can be inhibited.

[0042] The same antioxidants and refrigerant oils as those described above can also be used.

[0043] The system containing the antioxidant and the refrigerant (and optionally refrigerant oil) may also contain oxygen. The oxygen content is preferably 5,000 ppm by mass or less, more preferably 3,000 ppm by mass or less, and even more preferably 1,000 ppm by mass or less, based on the mass of fluoroethylene. By keeping the oxygen content in the system containing the refrigerant and antioxidant at 5,000 ppm by mass or less, based on the mass of fluoroethylene, the decomposition and polymerization reactions of the fluoroethylene are suppressed, as is the generation of hydrogen fluoride in the composition, thereby suppressing the deterioration of the composition.

[0044] The system containing the antioxidant and fluoroethylene (and optionally refrigerant oil) may also contain water.

[0045] Furthermore, the water content in the system containing the antioxidant and fluoroethylene (and optionally refrigerant oil) is preferably 100 ppm by mass or less, more preferably 50 ppm by mass or less, and even more preferably 20 ppm by mass or less, based on the mass of fluoroethylene. By limiting the water content to 100 ppm by mass or less based on the mass of fluoroethylene, the generation of solids due to side reactions, etc., can be suppressed, and the stability of fluoroethylene can be ensured.

[0046] The system containing the antioxidant and fluoroethylene (and optionally refrigerant oil) may contain substances other than those described above, as long as they do not impair the effect or purpose of the stabilization method of this disclosure. Such substances may be the same as those used in the compositions of this disclosure described above, and similar It can be included in that amount.

[0047] While embodiments of this disclosure have been described above, this disclosure is by no means limited to these examples, and can be implemented in various forms without departing from the gist of this disclosure. [Examples]

[0048] The embodiments of this disclosure will be described in more detail below based on the examples, but this disclosure is not limited to these examples.

[0049] (Example 1) Glass tubing with one end sealed by heat (ID 8mmΦ × OD 12mmΦ × L 300m) 0.466 μmol of BHT was added to (m), and then 8.9 mmol of 1,2-difluoroethylene was added. Next, 100 ppm by mass of oxygen was added to the 1,2-difluoroethylene. The tube was then sealed by melting. This tube was left standing in a constant temperature bath at 175°C and kept in this state for two weeks. After that, the tube was removed from the constant temperature bath, and the gas remaining inside the tube was completely solidified using liquid nitrogen. Then the tube was opened and gradually thawed, and the gas was collected in a Tedlar bag. 5 g of pure water was poured into this Tedlar bag, and the acid was extracted into the pure water while keeping it in good contact with the collected gas. The extract was detected by ion chromatography, and fluoride ions (F) were detected. - The amount of fluoride ions obtained by measuring the content (mass ppm) of fluoride was defined as the amount of hydrogen fluoride produced. As a result, the amount of hydrogen fluoride produced was less than 1 ppm.

[0050] (Comparative Example 1) The evaluation was carried out in the same manner as in Example 1, except that BHT was not added. After the test, analysis of the gas in the tube revealed that the amount of hydrogen fluoride produced was 67 ppm.

[0051] (Comparative Example 2) Glass tubing with one end sealed by heat (ID 8mmΦ × OD 12mmΦ × L 300m) 1.2 g of polyol ester-based refrigeration oil containing approximately 2% by mass of BHT was added to (m). Then, 8.9 mmol of 1,2-difluoroethylene was added. Next, 100 ppm by mass of oxygen was added relative to the 1,2-difluoroethylene. At this point, 109 μmol of BHT was present, and the refrigeration oil was present at 210% by mass relative to the 1,2-difluoroethylene. The tube was then sealed by heat sealing. This tube was placed in a constant temperature bath at 175°C and maintained in this state for two weeks. Afterward, the tube was removed from the constant temperature bath and the gas was analyzed using the same method as in Example 1. Despite the presence of excess BHT, the amount of hydrogen fluoride produced was 11 ppm.

Claims

**Claim 1** A composition comprising a refrigerant, an antioxidant, and oxygen, wherein the refrigerant contains fluoroethylene, the content of the antioxidant is 1 to 20,000 mass ppm based on the mass of the fluoroethylene, and the total mass of the refrigerant and the antioxidant is 95 mass % or more in 100 mass % of the whole composition, and the content of the oxygen is 5,000 mass ppm or less based on the mass of the fluoroethylene. **Claim 2** The composition according to claim 1, wherein the content of the refrigeration machine oil is 0 to 30,000 mass ppm based on the mass of the fluoroethylene. **Claim 3** The composition according to claim 1 or 2, wherein the antioxidant is at least one selected from the group consisting of phenols, alkyl catechols, benzoquinones, phenothiazines, terpenes, terpenoids, and phthalates. **Claim 4** The composition according to claim 3, wherein the antioxidant is at least one selected from the group consisting of dibutylhydroxytoluene, myrcene, pinene, and limonene. **Claim 5** A method for stabilizing a composition containing fluoroethylene, the method including a step of obtaining the composition by coexisting a refrigerant, an antioxidant, and oxygen, wherein the refrigerant contains fluoroethylene, the content of the antioxidant is 1 to 20,000 mass ppm based on the mass of the fluoroethylene, the total mass of the refrigerant and the antioxidant is 95 mass % or more in 100 mass % of the whole composition, and the content of the oxygen is 5,000 mass ppm or less based on the mass of the fluoroethylene.