Composition, method for preserving refrigerant, and method for suppressing polymerization of refrigerant

Abstract

To provide a composition having suppressed polymerization of a refrigerant, a storage method, and a method for suppressing polymerization.SOLUTION: The present invention provides a composition comprising (1) a refrigerant and (2) oxygen, wherein the oxygen (2) has concentration of 1 ppm or more by volume at a temperature of 25°C.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a composition, a method for storing a refrigerant, and a method for suppressing polymerization of a refrigerant.

Background Art

[0002] Patent Document 1 discloses a method for storing 2,3,3,3 - tetrafluoropropene in a sealed container in a gas - liquid state having a gas phase and a liquid phase, wherein the concentration of oxygen in the gas phase is set to be 3 volume ppm or more and less than 1,000 volume ppm at a temperature of 25°C. A method for storing tetrafluoropropene is disclosed.

[0003] Patent Document 1 also discloses a method for storing trifluoroethylene in a sealed storage container, wherein trifluoroethylene is stored in a state where a gas phase and a liquid phase coexist in the storage container, and the concentration of oxygen in the gas phase at a temperature of 25°C is maintained at 3 to 1,000 volume ppm. A method for storing trifluoroethylene is disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide a composition in which polymerization of a refrigerant is suppressed, a storage method, and a polymerization suppression method.

Means for Solving the Problems

[0006] The present disclosure includes the configurations described in the following items.

[0007] Item 1. A composition comprising (1) a refrigerant and (2) oxygen, wherein the (1) refrigerant is, (1-1) At least one or more components selected from the group consisting of cis-1,2-difluoroethylene (HFO-1132(Z)), 1,1-difluoroethylene (HFO-1132a), trifluoroethylene (HFO-1123), and tetrafluoroethylene (FO-1114 ), and (1-2) General formula (1):

[0008] [Chemical formula]

[0009] (wherein, Xa, Xb, and Xc represent a hydrogen atom or a fluorine atom, Ra is -CH3, -CHF2, -CH2F, -CF3, -CX d =CX e X f (wherein the X d , X e , X f represents a hydrogen atom or a fluorine atom), or -ORb (wherein Rb represents a hydrocarbon group having 1 to 3 carbon atoms and having a hydrogen atom or a fluorine atom as a substituent).) a compound represented by, and at least one or more components selected from the group consisting of trifluoroiodomethane (CF3I), and wherein the (2) oxygen is, based on volume, at a concentration of 1 ppm or more and 10,000 ppm or less at a temperature of 25°C. A composition characterized by this.

[0010] Item 2. Based on the total refrigerant, on a mass basis, the refrigerant (1-1) is 10% or more and 90% or less, the refrigerant (1-2) is 10% or more and 90% or less. The composition according to Item 1 above.

[0011] Item 3. A method for storing a refrigerant in a gas-liquid state having a gas phase and a liquid phase in a sealed container, wherein the refrigerant (1) is (1-1) at least one or more components selected from the group consisting of cis-1,2-difluoroethylene (HFO-1132(Z)), 1,1-difluoroethylene (HFO-1132a), trifluoroethylene (HFO-1123), and tetrafluoroethylene (FO-1114 ), and (1-2) General formula (1):

[0012]

Chemical formula

[0013] (wherein Xa, Xb, and Xc represent a hydrogen atom or a fluorine atom, Ra is -CH3, -CHF2, -CH2F, -CF3, -CX d =CX e X f (wherein the X d , X e , X f represents a hydrogen atom or a fluorine atom), or -ORb (wherein Rb represents a hydrocarbon group having 1 to 3 carbon atoms and having a hydrogen atom or a fluorine atom as a substituent).) and at least one or more components selected from the group consisting of compounds represented by and trifluoroiodomethane (CF3I), and in the gas phase, (2) oxygen is adjusted to a concentration of 1 ppm or more and 10,000 ppm or less at a temperature of 25°C on a volume basis, characterized by the method.

[0014] Item 4. Based on the total refrigerant, on a mass basis, the refrigerant (1-1) is 10% or more and 90% or less, The refrigerant (1-2) is 10% or more and 90% or less, and the method according to item 3 above.

[0015] Item 5. In a sealed container, in a gas-liquid state having a gas phase and a liquid phase, (1) a method for suppressing the polymerization of a refrigerant exists, The refrigerant in (1) is (1-1) cis-1,2-difluoroethylene (HFO-1132(Z)), 1,1-difluoroethylene (HFO-1132a), trifluoroethylene (HFO-1123), and tetrafluoroethylene (FO-1114 ) and at least one or more components selected from the group consisting of (1-2) General formula (1):

[0016]

Chemical formula

[0017] (In the formula, Xa, Xb, and Xc represent a hydrogen atom or a fluorine atom, Ra is -CH3, -CHF2, -CH2F, -CF3, -CX d =CX e X f (The X d , X e , X f represents a hydrogen atom or a fluorine atom), or -ORb (the Rb represents a hydrocarbon group having 1 to 3 carbon atoms and having a hydrogen atom or a fluorine atom as a substituent).) and at least one or more components selected from the group consisting of compounds represented by and trifluoroiodomethane (CF3I), In the gas phase, (2) oxygen is made to have a concentration of 1 ppm or more and 10,000 ppm or less at a temperature of 25°C on a volume basis, A method characterized by this.

[0018] Item 6. Based on the entire refrigerant, on a mass basis, The refrigerant (1-1) is 10% or more and 90% or less, The refrigerant (1-2) is 10% or more and 90% or less, the method according to item 5 above.

Advantages of the Invention

[0019] The method of the present disclosure can store the refrigerant well.

[0020] The method of the present disclosure can suppress the polymerization of the refrigerant well.

Embodiments for Carrying Out the Invention

[0021] The inventors of the present invention have conducted intensive research to improve the storage stability and polymerization inhibition of the refrigerant in a refrigerant composition containing the refrigerant and oxygen. As the refrigerant, (1-1) at least one component selected from the group consisting of HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114, and (1-2) a compound represented by the general formula (1), preferably, at least one component selected from the group consisting of HFO-1234yf and CF3I It has been found that the object can be achieved by coexisting at least one component selected.

[0022] Hereinafter, the embodiments included in the present disclosure will be described in detail.

[0023] <Definition of Terms> In this specification, the term "refrigerant" includes at least 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 furthermore, even if a refrigerant number has not been assigned yet, those having characteristics equivalent to those of such refrigerants are included.

[0024] Refrigerants are roughly classified into "fluorocarbon-based compounds" and "non-fluorocarbon-based compounds" in terms of the structure of the compounds. "Fluorocarbon-based compounds" include hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). "Non-fluorocar Examples of the "hydrocarbon compound" include propane (R290), propylene (R1270), butane (R600) , isobutane (R600a), etc.

[0025] In this specification, the term "composition containing a refrigerant" includes (1) the refrigerant itself (including refrigerant mixtures), (2) a composition that further contains other components and can be used to obtain a refrigeration working fluid by mixing with at least refrigeration oil, and (3) a refrigeration working fluid containing refrigeration oil. Among these three aspects, in this specification, the composition of (2) is distinguished from the refrigerant itself (including refrigerant mixtures) and is denoted as "refrigerant composition".

[0026] In this specification, the refrigeration working fluid of (3) is distinguished from the "refrigerant composition" and is denoted as "working fluid containing refrigeration oil".

[0027] In this specification, the term "substitute" is used in the context of "substituting" the first refrigerant with the second refrigerant. As the first type, in equipment designed to operate using the first refrigerant, it means that the second refrigerant can be used to operate under optimal conditions with only minor component changes (at least one of refrigeration oil, gaskets, packings, expansion valves, driers, and other components) and equipment adjustment as necessary.

[0028]

[0029] That is, this type refers to operating the same device by "replacing" the refrigerant. As modes of "replacement" of this type, there may be "drop-in replacement", "nearly drop-in replacement", and "retrofit" in ascending order of the degree of change or adjustment required when replacing with a second refrigerant.

[0030] As a second type, using a device designed to operate with a second refrigerant by mounting and using the second refrigerant for the same use as the existing use of the first refrigerant is also included in the term "replacement". This type refers to providing the same use by "replacing" the refrigerant.

[0031] In this specification, the term "refrigerator" generally refers to a device that removes heat from an object or space to a temperature lower than the surrounding outside air and maintains this low temperature. In other words, a refrigerator refers to a conversion device that obtains energy from the outside, performs work, and converts energy to move heat from a lower temperature to a higher temperature.

[0032] In this specification, the terms "contain" and "include" include the concepts of "contain", "include", "consist essentially of", and "consist only of".

[0033] In this specification, when a numerical range is described stepwise, the upper limit value or lower limit value of a numerical range at a certain step can be arbitrarily combined with the upper limit value or lower limit value of a numerical range at other steps.

[0034] In this specification, the upper limit value or lower limit value of the described numerical range may be replaced with the value shown in the examples or a value uniquely derivable from the examples.

[0035] In this specification, the main refrigerants are described as follows.

[0036] cis-1,2-difluoroethylene: HFO-1132(Z) ((Z)-1,2-difluoroethylene) 1,1-Difluoroethylene: HFO-1132a Trifluoroethylene: HFO-1123 Tetrafluoroethylene: FO-1114 2,3,3,3-Tetrafluoropropene: HFO-1234yf Trifluoroiodomethane: CF3I "(E / Z)" means including the E-isomer (trans-isomer) and / or the Z-isomer (cis-isomer).

[0037] [1] Composition (1) Refrigerant The composition of the present disclosure includes (1) a refrigerant and (2) oxygen, wherein the (1) refrigerant is (1-1) at least one or more components selected from the group consisting of cis-1,2-difluoroethylene (HFO-1132(Z)), 1,1-difluoroethylene (HFO-1132a), trifluoroethylene (HFO-1123), and tetrafluoroethylene (FO-1114 ), and (1-2) General formula (1):

[0038]

Chemical formula

[0039] (wherein Xa, Xb, and Xc represent a hydrogen atom or a fluorine atom, Ra is -CH3, -CHF2, -CH2F, -CF3, -CX d =CX e X f (wherein the X d , X e , X f represent a hydrogen atom or a fluorine atom), or -ORb (wherein Rb represents a hydrocarbon group having 1 to 3 carbon atoms and having a hydrogen atom or a fluorine atom as a substituent).) A compound represented by the formula, and at least one component selected from the group consisting of trifluoroiodomethane (CF3I). The oxygen in (2) is at a concentration of 1 ppm or more and 10,000 ppm or less at a temperature of 25 °C on a volume basis. This is the characteristic.

[0040] The composition of the present disclosure is a refrigerant composition containing (1) a refrigerant and (2) oxygen. In the refrigerant composition, the refrigerant in (1) is preferably (1-1) At least one component selected from the group consisting of cis-1,2-difluoroethylene (HFO-1132(Z)), 1,1-difluoroethylene (HFO-1132a), trifluoroethylene (HFO-1123), and tetrafluoroethylene (FO-1114), and (1-2) a compound represented by the general formula (1), preferably at least one component selected from the group consisting of 2,3,3,3-tetrafluoropropene (HFO-1234yf) and trifluoroiodomethane (CF3I) coexist. That is, the refrigerant composition contains, as the refrigerant in (1), at least one component selected from the group consisting of (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114; and (1-2) At least one component selected from the group consisting of a compound represented by the general formula (1), preferably HFO-1234yf, and CF3I.

[0041] Preferably, based on the total mass of the refrigerant, the refrigerant (1-1) is 10% or more and 90% or less, and the refrigerant (1-2) is 10% or more and 90% or less by mass. (1-2) At least one component selected from the group consisting of a compound represented by the general formula (1), preferably HFO-1234yf, and CF3I; is included.

[0042] Preferably, when the refrigerant in (1) coexists, based on the total amount of the refrigerant, the refrigerant (1-1) is 10% or more and 90% or less, and the refrigerant (1-2) is 10% or more and 90% or less by mass.

[0043] Preferably, when the refrigerant in (1) coexists, based on the total amount of the refrigerant, ​Thus, on a mass basis, 90% or less and 10% or more of the above-mentioned (1-1) HFO-1132(Z), HFO-1132a, HFO-1123 , and at least one or more components selected from the group consisting of FO-1114 are present in an amount of 10% or more and 90% or less of the compound represented by the general formula (1) of (1-2), preferably, at least one or more components selected from the group consisting of HFO-1234yf and CF3I are coexisted.

[0044] The refrigerant of at least one or more components selected from the group consisting of the above-mentioned (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114 has an unsaturated bond, so its stability is not good. During storage (keeping) or transportation, etc., due to the passage of time, etc., self-polymerization may occur, and the quality of the refrigerant may deteriorate.

[0045] Also, when stored under conditions including oxygen, polymers (polymers) of the refrigerant may be generated, which may cause a pressure drop.

[0046] The composition of the present disclosure, as the above-mentioned (1) refrigerant, to at least one or more components selected from the group consisting of (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114, (1-2) a compound represented by the general formula (1 ) (preferably, at least one or more components selected from the group consisting of HFO-1234yf and CF3I) are coexisted (or added), whereby the polymerization rate of the refrigerant mixture can be reduced to the level of the polymerization rate of the added compound.

[0047] The above-mentioned (1) refrigerant is preferably 90% or less and 10% or more on a mass basis based on the entire refrigerant By allowing at least one or more components selected from the group consisting of (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114 described below to coexist with 10% or less, and 90% or less (preferable threshold value) of (1-2) a compound represented by general formula (1), preferably at least one or more components selected from the group consisting of HFO-1234yf and CF3I, no pressure drop is observed and good storage stability is exhibited.

[0048] The composition of the present disclosure preferably contains, as the (1) refrigerant, (1-1) at least one component selected from the group consisting of HFO-1132(Z), HFO-1132a, HFO-1123, and HFO-1114 as a main component. and (1-2) at least one component selected from the group consisting of a compound represented by general formula (1), preferably HFO-1234yf, and CF3I, is allowed to coexist as a minor component, thereby decreasing the polymerization rate of (1-1) at least one component selected from the group consisting of HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114, and A refrigerant composition capable of suppressing polymerization of at least one component selected from the group consisting of FO-1114 and FO-1114. This allows the composition to be prepared.

[0049] Among the refrigerants in (1), the refrigerants in (1-1) are HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114. The refrigerant having at least one component selected from the group consisting of the compounds represented by general formula (1) (1-2), preferably at least one component selected from the group consisting of HFO-1234yf and CF3I, is a component that inhibits the polymerization.

[0050] By employing the composition of the present disclosure, (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and at least one refrigerant component selected from the group consisting of FO-1114 can be stored well This is possible.

[0051] By adopting the composition of the present disclosure, (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and polymerization of at least one refrigerant component selected from the group consisting of FO-1114 can be suppressed well This is possible.

[0052] The method for producing the (1) refrigerant to be contained in the composition is not particularly limited. For example, various refrigerants can be produced by known production methods.

[0053] When the refrigerant is HFO-1132(Z), HFO-1132(Z) can be produced by a reaction of dehydrofluorinating 1,1,2-trifluoroethane (HFC-143 ), a reaction of hydrogenating (E) and / or (Z)-1,2-dichloro-1,2-difluoroethylene (CFO-1112(E / Z)), or a reaction of dehydrochlorinating 1-chloro-1,2-difluoroethane (HCFC-142a).

[0054] The total amount of the (1) refrigerant contained in the composition can be specified by gas chromatography This is possible.

[0055] The (1) refrigerant contained in the composition, based on the total refrigerant, is at least one component selected from the group consisting of (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114; and also, the total (by mass) of (1-2) a compound represented by the general formula (1), preferably at least one component selected from the group consisting of HFO-1234yf and CF3I; preferably contains 99.5 mass% or more, more preferably 99.9 mass% or more, still more preferably 99.99 mass% or more See, particularly preferably, it contains 99.999 mass% or more.

[0056] The (1) refrigerant contained in the composition is preferably at least one or more components selected from the group consisting of (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114; and (1-2) a compound represented by the general formula (1), preferably at least one or more components selected from the group consisting of HFO-1234yf and CF3I. It may consist essentially of only the components of (1-1) and (1-2).

[0057] The (1) refrigerant contained in the composition is at least one or more components selected from the group consisting of (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114; and (1-2) a compound represented by the general formula (1). It may contain compounds other than at least one or more components selected from the group consisting of (1-2) a compound represented by the general formula (1), preferably HFO-1234yf and CF3I.

[0058] For example, it can contain impurities (inevitable impurities) that may be mixed in during the production of the refrigerant.

[0059] As the impurities, for example, in the case of HFO-1132(Z), hydrogen fluoride, fluoroethylene , HFO-1123, 1,1,1-trifluoroethane, propylene, acetylene, difluoromethane (HFC-32), trifluoromethane, fluoromethane, 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-difluoro Chloroethane (HCFC-142a), 1,2-difluoroethane (HFC-152), chlorodifluoromethane (HCFC-22), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2-tetrafluoroethane (HFC-134), pentafluoroethane (HFC-125), HFO-1234yf, 1,2,3,3,3-pentafluoropropene (HFO-1225ye), 1,3,3,3-tetrafluoropropene (HFO-1234ze), 1,3,3,3-tetrafluoropropene (HFO-1234ze), fluoroethylene (HFO-1141), 3,3,3-trifluoropropene (HFO-1243zf), 1,1-difluoroethylene (HFO-1132a), 1-chloro-2,2-difluoroethylene (HCFO-1122), 1-chloro-1,2-difluoroethylene (HCFO-1122a), ethylene, etc. is as follows.

[0060] When the refrigerant (1) contained in the composition contains impurities of the refrigerant, its content is not particularly limited, and for example, it may be contained in an amount of 0.1 ppm or more and 10,000 ppm or less in terms of weight conversion. Within this range, the risk of inhibiting the stabilizing action of the refrigerant in the refrigerant composition is small.

[0061] When the refrigerant (1) of the present disclosure coexists, preferably, based on the total amount of the refrigerant, in terms of mass, at least one or more components selected from the group consisting of 90% or less and 10% or more of the above (1-1) HFO-1132(Z), HFO-1132a, HFO-1123 and FO-1114 coexist with 10% or more and 90% or less of the compound represented by the general formula (1) of (1-2), preferably at least one or more components selected from the group consisting of HFO-1234yf and CF3I.

[0062] When the refrigerant (1) coexists, more preferably based on the total amount of the refrigerant, in terms of mass, is 90% or less, 10% or more of at least one component selected from the group consisting of the above (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114, and 90% or less, 10% or more of (1-2) general formula (1) The compound represented by, preferably, at least one component selected from the group consisting of HFO-1234yf and CF3I is allowed to coexist.

[0063] (2) Oxygen The composition of the present disclosure contains the above (1) refrigerant and can be used for the same applications as the refrigerant. It can be used.

[0064] The composition of the present disclosure contains (1) refrigerant and (2) oxygen, and the above (1) refrigerant can be stored or polymerization can be suppressed in a gas-liquid state having a gas phase and a liquid phase in a sealed container. In the above (1 ) refrigerant, the concentration of the above (2) oxygen in the gas phase is allowed to coexist at 1 ppm or more and 10,000 ppm or less on a volume basis at a temperature of 25°C. It can be stored or polymerization can be suppressed in a gas-liquid state having a gas phase and a liquid phase in a sealed container. In the above (1 ) refrigerant, the concentration of the above (2) oxygen in the gas phase is allowed to coexist at 1 ppm or more and 10,000 ppm or less on a volume basis at a temperature of 25°C.

[0065] In the composition of the present disclosure, preferably, when the above (2) oxygen is allowed to coexist, the concentration of the above (2) oxygen in the gas phase is allowed to coexist at 1 ppm or more and 10,000 ppm or less on a volume basis at a temperature of 25°C. And the step of allowing the concentration of the above (2) oxygen in the gas phase to coexist at 1 ppm or more and 10,000 ppm or less on a volume basis at a temperature of 25°C.

[0066] Among the above (1) refrigerants, the refrigerant of at least one component selected from the group consisting of the above (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114, particularly when stored under conditions including oxygen, when storing the refrigerant alone, a polymer (polymer) of the refrigerant may be generated, causing a pressure drop. Among the above (1) refrigerants, the refrigerant of at least one component selected from the group consisting of the above (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114, particularly when stored under conditions including oxygen, when storing the refrigerant alone, a polymer (polymer) of the refrigerant may be generated, causing a pressure drop.

[0067] The present disclosure is applicable even when the composition contains (2) oxygen in addition to the above (1) refrigerant. (1-2) One A compound represented by the general formula (1), preferably at least one component selected from the group consisting of HFO-1234yf and CF3I is coexisted. By coexisting at least one component selected from the group consisting of (1-1) HFO-1132(Z), HFO-1132a , HFO-1123, and FO-1114, the polymerization rate of at least one component selected from the group can be reduced to about the level of HFO-1234yf, showing no pressure drop and good storage stability.

[0068] The composition of the present disclosure can store a composition containing a refrigerant well and can suppress the polymerization of the refrigerant well.

[0069] In the composition of the present disclosure, the concentration of the (2) oxygen coexisted in the gas phase in the (1) refrigerant refers to the oxygen concentration when the gas temperature is 25°C. In a sealed container, the (1) refrigerant is held in a state where the gas phase and the liquid phase coexist under pressure (gas-liquid coexistence state), so in the gas phase, the (1) refrigerant shows a saturated vapor pressure. The concentration of the (2) oxygen means the content ratio of oxygen in the gas phase of the (1) refrigerant.

[0070] The concentration of the (2) oxygen coexisted in the (1) refrigerant is 1 ppm or more, preferably 3 ppm or more, more preferably 10 ppm or more, and still more preferably 20 ppm or more on a volume basis at a temperature of 25°C.

[0071] Among the (1) refrigerants, the (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114 When a refrigerant having at least one component selected from the group consisting of the above is stored under conditions containing oxygen, when the refrigerant is stored alone, a polymer (polymerization product) of the refrigerant may be generated, causing a drop in pressure. The concentration of the above (2) oxygen coexisting with the above (1) refrigerant is preferably 10,000 ppm or less, more preferably 10,000 ppm or less, on a volume basis, at a temperature of 25°C, as an allowable oxygen concentration range. It is preferably 1,000 ppm or less, more preferably 100 ppm or less, and particularly preferably 50 ppm or less.

[0072] The concentration of the oxygen in the gas phase (2) is 10,000 ppm or less, A compound represented by the general formula (1), preferably selected from the group consisting of HFO-1234yf and CF3I. By allowing at least one or more components selected from the group consisting of (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114 to coexist, reactions such as polymerization of at least one or more components selected from the group consisting of HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114 in the liquid phase and gas phase can be sufficiently prevented.

[0073] A portion of the (1) refrigerant in the storage container may be removed, and the remaining (1) refrigerant may then continue to be stored in the storage container. In this case, the volume of the gas phase in the storage container increases, but the oxygen concentration in the gas phase with increased volume is preferably maintained at 10,000 ppm or less on a volume basis. The oxygen concentration in the gas phase is usually in equilibrium with the oxygen concentration in the (1) refrigerant in the liquid phase, and oxygen does not enter the storage container when a portion of the (1) refrigerant is removed. As long as the oxygen concentration in the gas phase is kept constant, it is believed that the oxygen concentration in the gas phase will not increase substantially.

[0074] The concentration of (2) oxygen in the gas phase can be controlled by pressurizing the (1) refrigerant to produce a liquid, and injecting the liquid into a sealed container in which the air has been vacuum-deaerated in advance and the concentration of (2) oxygen has been reduced, preferably to 10,000 ppm or less on a volume basis. When a liquid is poured into a container, the space inside the container is quickly saturated with vapor from the liquid. And the concentration of (2) oxygen in the gas phase thus filled with the saturated vapor of the (1) refrigerant is preferably 10,000 ppm or less on a volume basis.

[0075] In addition, when degassing a sealed container under vacuum, non-condensable gases such as nitrogen are excluded together with oxygen, but the total content of non-condensable gases is preferably an amount not exceeding 1.5% by volume (15,000 ppm) at a temperature of 25.0 °C on a volume basis.

[0076] (3) Other components contained in the refrigerant composition The composition of the present disclosure can be further used to obtain a refrigerant working fluid by mixing it with at least refrigeration oil.

[0077] In addition to the (1) refrigerant and the (2) oxygen, the refrigerant composition may further contain at least one other component. The other component is, for example, at least one selected from the group consisting of water, tracer, air, impurities, and by-products.

[0078] In the refrigerant composition, the content of the other component is preferably 0.01% by mass or more based on the total mass of the refrigerant composition. In the refrigerant composition, the content of the other component is preferably 1% by mass or less, more preferably 0.1% by mass or less, based on the total mass of the refrigerant composition.

[0079] (4) Refrigerant oil-containing working fluid The composition of the present disclosure preferably further contains refrigeration oil and is used as a working fluid (refrigeration oil-containing working fluid) in a refrigerator.

[0080] Specifically, the refrigeration oil-containing working fluid is obtained by mixing the refrigeration oil used in the compressor of the refrigerator with the refrigerant or the refrigerant composition.

[0081] The refrigerant oil-containing working fluid changes its composition in the refrigeration cycle. Specifically, the refrigerant oil content of the refrigerant oil-containing working fluid is relatively high in the compressor, is discharged from the compressor in a mist form, circulates in the refrigeration cycle, and is relatively low during the period until it returns to the compressor. 。

[0082] The refrigerant oil content of the refrigerant oil-containing working fluid is preferably 30% by mass or more and 70% by mass or less in the compressor.

[0083] The refrigerant oil content of the refrigerant oil-containing working fluid is preferably 1 ppm by mass or more and 20% by mass or less, more preferably 10% by mass during the period from being discharged from the compressor until it returns to the compressor again.

[0084] The base oil of the refrigerant oil is preferably a lubricating oil, is not particularly limited, and for example, known lubricating oils used for refrigerants and the like are widely adopted.

[0085] As specific lubricants, at least one lubricating oil selected from the group consisting of polyalkylene glycol (PAG), polyol ester (POE), and polyvinyl ether (PVE) is preferably used. As polyalkylene glycol (PAG), for example, "SUNICE P56" manufactured by Nippon Sun Oil Co., Ltd. and the like can be mentioned. Also, as polyol ester (POE), for example, "Ze-GLES RB32" manufactured by JX Nippon Oil & Energy Corporation and the like can be mentioned.

[0086] In addition to the base oil, the refrigerant oil preferably further contains at least one additive. The additive is preferably at least one component selected from the group consisting of a compatibilizer, an ultraviolet fluorescent dye, a stabilizer, a polymerization inhibitor, an antioxidant, an extreme pressure agent, an acid scavenger, an oxygen scavenger, a copper deactivator, a rust inhibitor, an oiliness agent, and an antifoaming agent.

[0087] (5) Method for preparing the refrigerant composition and the refrigerant oil-containing working fluid The method for preparing the composition of the present disclosure is not particularly limited.

[0088] The method for preparing the refrigerant composition is preferably, for example, a method of mixing the above (1) refrigerant, (2) oxygen, etc. at a predetermined blending ratio. In this mixing, the above-mentioned lubricating oil and / or other additives can be appropriately blended.

[0089] [2] Method for storing the refrigerant The method for storing the (1) refrigerant of the present disclosure is a method of storing the (1) refrigerant in a gas-liquid state having a gas phase and a liquid phase in a sealed container and the (1) refrigerant is the above (1) refrigerant is (1-1) at least one or more components selected from the group consisting of cis-1,2-difluoroethylene (HFO-1132(Z)), 1,1-difluoroethylene (HFO-1132a), trifluoroethylene (HFO-1123), and tetrafluoroethylene (FO-1114 ), and (1-2) general formula (1):

[0090]

Chemical formula

[0091] (wherein Xa, Xb, and Xc represent a hydrogen atom or a fluorine atom, Ra is -CH3, -CHF2, -CH2F, -CF3, -CX d =CX e X f (where the X d , X e , X f represents a hydrogen atom or a fluorine atom), or -ORb (where Rb represents a hydrocarbon group having 1 to 3 carbon atoms and having a hydrogen atom or a fluorine atom as a substituent).). and includes at least one or more components selected from the group consisting of the compound represented by the formula and trifluoroiodomethane (CF3I), In the gas phase, (2) oxygen is adjusted to a concentration of 1 ppm or more and 10,000 ppm or less at a temperature of 25 °C on a volume basis. A method characterized by the above.

[0092] In the method for storing the refrigerant (1) of the present disclosure, preferably, based on the entire refrigerant, On a mass basis, the refrigerant (1-1) is 10% or more and 90% or less, and the refrigerant (1-2) is 10% or more and 90% or less.

[0093] For each component such as the refrigerant and the refrigeration oil used in the method for storing the refrigerant, the components described in the item of the composition can be used.

[0094] Storage container In the method for storing the refrigerant or the method for suppressing polymerization of the present disclosure, the storage container of the refrigerant composition is preferably a sealed container that can enclose the refrigerant (1) in a gas-liquid coexistence state under an internal pressure. is used. The storage container of the refrigerant composition does not require a special structure or constituent material and can have a wide range of forms and functions.

[0095] The storage container of the refrigerant composition is preferably, for example, a storage tank which is a fixed storage container, a pressure-resistant container such as a filling cylinder used for transportation, a secondary filling cylinder (service cylinder), etc. and the like.

[0096] As the constituent material of the storage container of the refrigerant composition, preferably, for example, carbon steel, manganese steel, chromium molybdenum steel, other low alloy steels, stainless steel, aluminum alloy, etc. are used.

[0097] [3] Method for suppressing polymerization of the refrigerant The method for suppressing the polymerization of the refrigerant (1) of the present disclosure is a method for suppressing the polymerization of the refrigerant (1) in a gas-liquid state having a gas phase and a liquid phase in a sealed container. The refrigerant (1) is as described above. (1-1) cis-1,2-difluoroethylene (HFO-1132(Z)), 1,1-difluoroethylene (HFO-1132a), trifluoroethylene (HFO-1123), and tetrafluoroethylene (FO-1114 ) and at least one component selected from the group consisting of (1-2) General formula (1):

[0098] [Chemical formula]

[0099] (In the formula, Xa, Xb, and Xc represent a hydrogen atom or a fluorine atom, Ra is -CH3, -CHF2, -CH2F, -CF3, -CX d =CX e X f (wherein the X d , X e , X f represent a hydrogen atom or a fluorine atom), or -ORb (wherein Rb represents a hydrocarbon group having 1 to 3 carbon atoms and having a hydrogen atom or a fluorine atom as a substituent).) a compound represented by and at least one component selected from the group consisting of trifluoroiodomethane (CF3I), in the gas phase, (2) oxygen is adjusted to a concentration of 1 ppm or more and 10,000 ppm or less at a temperature of 25°C on a volume basis, A method characterized by this.

[0100] In the method for suppressing polymerization of the refrigerant of the present disclosure, preferably, based on the entire refrigerant on a mass basis, the refrigerant (1-1) is 10% or more and 90% or less, and the refrigerant (1-2) is 10% or more and 90% or less.

[0101] For use in a method for suppressing polymerization of a refrigerant, each component such as a refrigerant and a refrigeration oil can use the components described in the item of the composition.

[0102] [4] Evaluation method for the storage method of the refrigerant composition and the refrigerant oil-containing working fluid According to the method for storing a refrigerant of the present disclosure (storage method) and the method for suppressing polymerization of a refrigerant (polymerization suppression method), among the above-mentioned (1) refrigerants filled in a sealed container in a gas-liquid state, at least one selected from the group consisting of the above-mentioned (1-1) HFO-1132(Z), HFO-1132a, HFO-1123, and FO-1114 Reactions such as polymerization are suppressed in the refrigerant of the above components, and the purity of the above-mentioned (1) refrigerant and the refrigerant Thus, high quality can be maintained.

[0103] According to the storage method and the polymerization suppression method of the present disclosure, it is possible to suppress the generation of, for example, solid polymerization products in a sealed container, and there is no risk of blockage of valves or the like or contamination of foreign substances into the refrigerant system.

[0104] According to the storage method and the polymerization suppression method of the present disclosure, the polymerization of the above-mentioned (1) refrigerant can be suppressed and stored well at low cost. It can be suppressed and stored.

[0105] In the storage method and the polymerization suppression method of the present disclosure, the evaluation of the storage stability of the refrigerant is, for example, enclosing the above-mentioned (1) refrigerant in a gas-liquid state together with a predetermined amount of (2) oxygen in a sealed container, heating the whole to a predetermined temperature, holding it in a constant temperature state for a predetermined time, and then identifying and analyzing the reaction products in the liquid phase of the above-mentioned (1) refrigerant. It can be carried out by identification and analysis.

[0106] This evaluation corresponds to an accelerated test with a heat load.

[0107] The heating temperature can be set in the range of -70°C or higher and 300°C or lower, which is the set temperature range of the constant temperature bath. Also, the heat treatment time can be arbitrarily set. The identification and analysis of the reaction products can be carried out, for example, by the method described in the examples below.

Examples

[0108] Hereinafter, the present disclosure will be described more specifically by way of examples, but the present disclosure is not limited to the embodiments thereof.

[0109] Method for storing the refrigerant and method for suppressing polymerization of the refrigerant (1) Evaluation method for the amount of polymerization composition generated in the polymerization reaction The following shows the experimental methods common in the polymerization reaction evaluation.

[0110] A pressure-resistant container made of SUS316 with an internal volume of 200 cc (maximum operating temperature: 300 °C, maximum operating pressure: 20 MPa) was sealed , and the inside of the container was evacuated. 150 g of perfluorocyclobutane was placed therein, and 0.16 mol of a gas containing at least one of HFO-1123, HFO-1132(Z), HFO-1132a, and HFO-1234yf was added. The container was placed in a water bath to keep the internal temperature of the container at 25 °C for heat preservation, and after confirming that the internal temperature of the container was stable , 1 g of an 8 mass% perfluorohexane solution of bis(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptanoyl) peroxide was added as an initiator to start the polymerization. After continuing the polymerization while maintaining the temperature at 25 °C, when 2 hours had elapsed since the start of the polymerization, the polymerization was stopped by releasing the internal gas . After the polymerization was stopped, the solid content inside the container was taken out and dried by heating at 120 °C in a vacuum , and the weight was measured. The obtained solid was dissolved in deuterated acetone 1 and the 1H-NMR, 13 13C-NMR, and 19 19F-NMR spectra were measured.

[0111] (1-1) Polymerization reaction of HFO-1123 alone According to the above common method, 13.2 g of HFO-1123 was placed in the container to carry out a polymerization reaction. The solid obtained after the polymerization reaction was 2.0 g. By attributing the peaks of the measured NMR spectra , when the solid substance was identified, it was confirmed that it was a homopolymer of HFO-1123. The HFO-1123 used in the polymerization reaction was 0.024 mol.

[0112] (1-2) Polymerization reaction of HFO-1132a alone According to the above common method, 10.2 g of HFO-1132a was placed in a container and a polymerization reaction was carried out. The solid obtained after the polymerization reaction was 3.9 g. According to the peak assignment of the measured NMR spectrum When the solid substance was identified, it was confirmed to be a homopolymer of HFO-1132a. The polymerization reaction The HFO-1132a used in was 0.061 mol.

[0113] (1-3) Polymerization reaction of HFO-1132(Z) alone According to the above common method, 10.2 g of HFO-1132(Z) was placed in a container and a polymerization reaction was carried out. The solid obtained after the polymerization reaction was 0.7 g. According to the peak assignment of the measured NMR spectrum by which the solid substance was identified, it was confirmed to be a homopolymer of HFO-1132(Z). The polymerization The HFO-1132(Z) used in the reaction was 0.011 mol.

[0114] (1-4) Polymerization reaction of HFO-1234yf alone According to the above common method, 18.4 g of HFO-1234yf was placed in a container and a polymerization reaction was carried out. The poly merization The solid obtained after the reaction was 0.15 g. According to the peak assignment of the measured NMR spectrum, when the solid substance was identified, it was confirmed to be a homopolymer of HFO-1234yf. The HFO-1234yf used in the polymerization reaction was 0.0013 mol.

[0115] (1-5) Polymerization reaction of HFO-1123 and HFO-1234yf with a weight ratio of 37 / 63 According to the above common method, 15.9 g of a 37 / 63 weight ratio mixture of HFO-1123 and HFO-1234yf was placed in a container and a polymerization reaction was carried out. The solid obtained after the polymerization reaction was 0.15 g. When the solid substance was identified by the peak assignment of the measured NMR spectrum, it was confirmed to be a copolymer of HFO-1123 and HFO-1234yf, and the monomer composition in the polymer was almost the same as the ratio of HFO-1123 and HFO-1234yf placed in the container. The mixture of HFO-1123 and HFO-1234yf used in the polymerization reaction was 0.0015 mol.

[0116] (1-6) Polymerization reaction of HFO-1123 and HFO-1234yf with a weight ratio of 80 / 20 According to the above common method, 13.9 g of an 80 / 20 weight ratio mixture of HFO-1123 and HFO-1234yf was placed in a container and a polymerization reaction was carried out. The solid obtained after the polymerization reaction was 0.13 g. When the solid substance was identified by the peak assignment of the measured NMR spectrum, it was confirmed to be a copolymer of HFO-1123 and HFO-1234yf, and the monomer composition in the polymer was almost the same as the ratio of HFO-1123 and HFO-1234yf placed in the container. The mixture of HFO-1123 and HFO-1234yf used in the polymerization reaction was 0.0015 mol.

[0117] (1-7) Polymerization reaction of HFO-1123 and HFO-1234yf with a weight ratio of 90 / 10 According to the above common method, 13.5 g of an 80 / 20 weight ratio mixture of HFO-1123 and HFO-1234yf was placed in a container and a polymerization reaction was carried out. The solid obtained after the polymerization reaction was 0.14 g. When the solid substance was identified by the peak assignment of the measured NMR spectrum, it was confirmed to be a copolymer of HFO-1123 and HFO-1234yf, and the monomer composition in the polymer was almost the same as the ratio of HFO-1123 and HFO-1234yf placed in the container. The mixture of HFO-1123 and HFO-1234yf used in the polymerization reaction was 0.0017 mol.

[0118] (1-8) Polymerization reaction of HFO-1123 and HFO-1234yf with a weight ratio of 93 / 7 According to the above common method, 13.2 g of an 80 / 20 weight ratio mixture of HFO-1123 and HFO-1234yf was placed in a container and a polymerization reaction was carried out. The solid obtained after the polymerization reaction was 0.14 g. When the solid substance was identified by the peak assignment of the measured NMR spectrum, it was confirmed that it was a copolymer of HFO-1123 and HFO-1234yf, and the monomer composition in the polymer was almost the same as the ratio of HFO-1123 and HFO-1234yf placed in the container. The mixture of HFO-1123 and HFO-1234yf used in the polymerization reaction was 0.0074 mol.

[0119] (2) Evaluation method for the storage or polymerization suppression of the refrigerant The following shows the common experimental methods in the evaluation of storage or polymerization inhibition.

[0120] A pressure-resistant container made of SUS316 with an internal volume of 40 cc (maximum operating temperature 300 °C, maximum operating pressure 20 MPa) was sealed, and the inside of the container was evacuated. Next, after enclosing a predetermined amount of oxygen in the pressure-resistant container, a predetermined amount of liquefied refrigerant with a purity of 99.5% or more was filled. The container with the coexistence of the refrigerant and oxygen was placed in a constant temperature bath maintained at 50 °C and left to stand, and the internal temperature and pressure of the container were observed.

[0121] Unless otherwise specified, the pressure is the gauge pressure.

[0122] (2-1) Evaluation of oxygen coexistence in HFO-1123 In the container described above, when HFO-1123 coexisted, oxygen at an absolute pressure of 0.1 MPa and 25 °C was enclosed so that it would be 14,000 ppm per unit volume. After the container was cooled with liquid nitrogen and then filled with 9.4 g of HFO-1123 so that it was almost equal to the saturated vapor pressure of HFO-1123 at 50 °C and coexisted. The container was left to stand in a constant temperature bath maintained at 50 °C, and the internal temperature and pressure of the container were observed. The internal pressure when the internal temperature reached 50 °C was 3.65 MPa. It was confirmed that the internal pressure began to decrease after 85 hours had elapsed. The internal pressure reduction was continuous. After 240 hours, the internal pressure reached 0.65 MPa. The container was taken out of the constant temperature bath, and the internal gas was released. The solid matter adhering inside was taken out and heated and dried at 120 °C in vacuo, and the weight was measured to be 8.3 g. The obtained solid was dissolved in deuterated acetone and 1 1H-NMR, 13 13C-NMR, and 19 19F-NMR spectra were measured, and the solid substance was identified by peak assignment of the NMR spectra . As a result, it was confirmed that it was a homopolymer of HFO-1123.

[0123] (2-2) Evaluation of low oxygen concentration in HFO-1123 After cooling the above-described container with liquid nitrogen, 9.4 g of HFO-1123 was filled so as to be approximately equal to the saturated vapor pressure of HFO-1123 at 50 °C. The container was placed still in a constant temperature bath maintained at 50 °C, and the internal temperature and internal pressure of the container were observed. The internal pressure when the internal temperature reached 50 °C was 3.60 MPa. After 240 hours, it was confirmed that the internal pressure did not change from 3.60 MPa. The container was taken out of the constant temperature bath, and the internal gas was released. It was confirmed visually that there was no adhesion of solid matter inside.

[0124] (2-3) Evaluation of oxygen coexistence in HFO-1234yf When oxygen at an absolute pressure of 0.02 MPa at 25 °C was enclosed in the above-described container so that the volume ratio of HFO-1234yf was 14,000 ppm, the container was cooled with liquid nitrogen, and then 3.0 g of HFO-1234yf was filled so as to be approximately equal to the saturated vapor pressure of HFO-1123 at 50 °C, and they were made to coexist. The container was placed still in a constant temperature bath maintained at 50 °C, and the internal temperature and internal pressure of the container were observed. The internal pressure when the internal temperature reached 50 °C was 1.20 MPa. After 240 hours, it was confirmed that the internal pressure did not change from 1.20 MPa. The container was taken out of the constant temperature bath, and the internal gas was released. It was confirmed visually that there was no adhesion of solid matter inside.

[0125] (2-4) Evaluation of oxygen coexistence in HFO-1123 and HFO-1234yf with a weight ratio of 90 / 10 In the container described above, oxygen with an absolute pressure of 0.09 MPa at 25 °C was enclosed so that it would be 14,000 ppm per volume when coexisting with HFO-1123. After the container was cooled with liquid nitrogen, 8.4 g of HFO-1123 was filled so that it would be almost equal to the saturated vapor pressure of a 90 / 10 weight ratio mixed gas of HFO-1123 and HFO-1234yf at 50°C, and they were coexisted. The container was left standing in a constant temperature bath maintained at 50°C, and the internal temperature and pressure of the container were observed. The internal pressure when the internal temperature reached 50°C was 3.40 MPa. After 240 hours passed, it was confirmed that the internal pressure did not change from 3.40 MPa. The container was taken out of the constant temperature bath, and the internal gas was released. It was confirmed visually that there was no adhesion of solid matter inside.

[0126] (3) Results of the stability test of the refrigerant storage method or polymerization suppression method The mixed refrigerant of HFO-1123 and HFO-1234yf has HFO-1234yf coexisting with HFO-1123. Even when oxygen coexists in the refrigerant composition, no homopolymer of HFO-1123, which is a solid product causing practical problems in the liquid phase, and no copolymer of HFO-1123 and HFO-1234yf are observed, indicating that no polymerization reaction has occurred.

[0127] On the other hand, for the refrigerant of only HFO-1123, HFO-1234yf does not coexist, and when oxygen coexists in the refrigerant composition, the formation of the homopolymer of HFO-1123 is observed.

[0128] The method for storing or suppressing polymerization of the refrigerant of the present disclosure is a method for storing or suppressing polymerization of the (1) refrigerant in a refrigerant composition containing (1) the refrigerant and (2) oxygen in a sealed container, and the (1) As the refrigerant, (1-2) components such as HFO-1234yf coexist with (1-1) components such as HFO-1123 By doing so, even when the concentration of the (2) oxygen in the gas phase coexists with the (1) refrigerant at about 14,000 ppm on a volume basis at a temperature of 25°C, HFO-1123 and the like do not polymerize over a long period of time. It can be evaluated as an effective stable storage method capable of suppressing reactions.

[0129] According to the refrigerant storage method or polymerization suppression method of the present disclosure, since reactions such as polymerization can be suppressed in components such as HFO-1123, it is possible to provide a method for storage and transportation while suppressing self-polymerization of components such as HFO-1123 during storage and transportation, maintaining high quality without degrading the quality of the refrigerant.

Claims

1. A composition comprising (1) a refrigerant and (2) oxygen, wherein the (1) refrigerant is (1-1) at least one component selected from the group consisting of cis-1,2-difluoroethylene (HFO-1132(Z)), 1,1-difluoroethylene (HFO-1132a), trifluoroethylene (HFO-1123), and tetrafluoroethylene (FO-1114 ), and (1-2) General formula (1): 【Chemical 1】 (In the formula,[ Xa, Xb, and Xc represent a hydrogen atom or a fluorine atom,[ Ra is -CH 3 , -CHF 2 , -CH 2 F, -CF 3 , -CX d =CX e X f (wherein the X d , X e , X f represents a hydrogen atom or a fluorine atom), or -ORb (wherein Rb has 1 to 3 carbon atoms and has, as a substituent, a hydrogen atom or and represent a hydrocarbon group having a fluorine atom).) A compound represented by, and at least one or more components selected from the group consisting of trifluoroiodomethane (CF 3 I), and The (2) oxygen is characterized in that, based on volume, at a temperature of 25°C, the concentration is 1 ppm or more and 10,000 ppm or less. A composition characterized by this.

2. Based on the total amount of the refrigerant, on a mass basis,[ the refrigerant (1-1) is 10% or more and 90% or less,[ the refrigerant (1-2) is 10% or more and 90% or less. The composition according to claim 1.

3. A method for storing (1) a refrigerant in a gas-liquid state having a gas phase and a liquid phase in a sealed container, wherein the (1) refrigerant is (1-1) at least one component selected from the group consisting of cis-1,2-difluoroethylene (HFO-1132(Z)), 1,1-difluoroethylene (HFO-1132a), trifluoroethylene (HFO-1123), and tetrafluoroethylene (FO-1114 ), and (1-2) General formula (1): 【Chemical Formula 2】 (In the formula,[ Xa, Xb, and Xc represent a hydrogen atom or a fluorine atom,[ Ra is -CH 3 , -CHF 2 , -CH 2 F, -CF 3 , -CX d =CX e X f (wherein the said X d , X e , X f represents a hydrogen atom or a fluorine atom), or -ORb (wherein the said Rb has 1 to 3 carbon atoms and has a hydrogen atom as a substituent, or and represent a hydrocarbon group having a fluorine atom).) A compound represented by, and at least one or more components selected from the group consisting of trifluoroiodomethane (CF 3 I), and comprising In the gas phase, (2) oxygen is made to have a concentration of 1 ppm or more and 10,000 ppm or less at a temperature of 25°C based on volume,[ A method characterized by this.

4. Based on the total amount of the refrigerant, on a mass basis,[ the refrigerant (1-1) is 10% or more and 90% or less,[ the refrigerant (1-2) is 10% or more and 90% or less. The method according to claim 3.

5. A method for suppressing the polymerization of (1) a refrigerant in a gas-liquid state having a gas phase and a liquid phase in a sealed container,[ and the (1) refrigerant is (1-1) at least one component selected from the group consisting of cis-1,2-difluoroethylene (HFO-1132(Z)), 1,1-difluoroethylene (HFO-1132a), trifluoroethylene (HFO-1123), and tetrafluoroethylene (FO-1114 ), and (1-2) General formula (1): 【Chemical Formula 3】 (In the formula,[ Xa, Xb, and Xc each represent a hydrogen atom or a fluorine atom, Ra is -CH 3 , -CHF 2 , -CH 2 F, -CF 3 , -CX d =CX e X f (wherein the X d , X e , X f represents a hydrogen atom or a fluorine atom), or -ORb (wherein the Rb is a C1-C3 group having a substituent of a hydrogen atom or or a hydrocarbon group having a fluorine atom). A compound represented by, and at least one or more components selected from the group consisting of trifluoroiodomethane (CF 3 I), and In the gas phase, (2) oxygen is adjusted to a concentration of 1 ppm or more and 10,000 ppm or less at a temperature of 25°C on a volume basis, The method is characterized by this.

6. Based on the entire refrigerant by mass, The refrigerant (1-1) is 10% or more and 90% or less, The refrigerant (1-2) is 10% or more and 90% or less. The method according to claim 5.

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