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EP-4737533-A1 - METHOD FOR SUPPRESSING DISPROPORTIONATION REACTION OF WORKING MEDIUM FOR REFRIGERATION CYCLES, WORKING MEDIUM FOR REFRIGERATION CYCLES, AND REFRIGERATION CYCLE DEVICE

EP4737533A1EP 4737533 A1EP4737533 A1EP 4737533A1EP-4737533-A1

Abstract

Disclosed is a method of inhibiting a disproportionation reaction of a refrigeration-cycle working medium containing a refrigerant component that causes the disproportionation reaction, wherein in a refrigeration cycle in which the refrigeration-cycle working medium circulates, the refrigeration-cycle working medium contains a carbonyl compound, and the carbonyl compound includes, in its chemical structure, a carbon-oxygen double bond (C=O bond) that reacts with a carbene and at least one alpha hydrogen atom, the method including inhibiting the disproportionation reaction of the refrigerant component in such a manner that the carbonyl compound captures the carbene generated by the disproportionation reaction of the refrigerant component.

Inventors

  • SAKATA, NAOYA
  • MURAKAMI, HIKARU
  • TSUNOYAMA, HIRONORI
  • HASHIMOTO, TAKAHIKO

Assignees

  • Panasonic Intellectual Property Management Co., Ltd.

Dates

Publication Date
20260506
Application Date
20240625

Claims (20)

  1. A method of inhibiting a disproportionation reaction of a refrigeration-cycle working medium containing a refrigerant component that causes the disproportionation reaction, wherein in a refrigeration cycle in which the refrigeration-cycle working medium circulates, the refrigeration-cycle working medium contains a carbonyl compound, and the carbonyl compound includes, in its chemical structure, a carbon-oxygen double bond (C=O bond) that reacts with a carbene and at least one alpha hydrogen atom, the method comprising inhibiting the disproportionation reaction of the refrigerant component in such a manner that the carbonyl compound captures the carbene generated by the disproportionation reaction of the refrigerant component.
  2. The method according to claim 1, wherein the carbonyl compound is propionaldehyde, acetone, cyclopropanone, acetaldehyde, or a derivative of any of these compounds which includes three carbon atoms or less.
  3. The method according to claim 1, wherein the carbene includes at least one selected from the group consisting of CF 2 , CHF, and CH 2 .
  4. The method according to claim 1, wherein: the reaction between the carbonyl compound and the carbene includes converting the carbonyl compound into an ether compound; and the ether compound includes four carbon atoms or less and includes, as a terminal substituent of its molecular structure, at least one selected from the group consisting of a methyl group (CH 3 ), a monofluoromethyl group (CH 2 F), and a difluoromethyl group (CHF 2 ).
  5. The method according to claim 1 or 2, wherein: inhibiting the disproportionation reaction of the refrigerant component includes inhibiting an increase of the carbene in the refrigeration cycle; and inhibiting the increase of the carbene includes a process in which a concentration of the carbene falls below a preset upper limit of the concentration of the carbene or a process in which the concentration of the carbene is set to practically zero.
  6. The method according to claim 1 or 2, wherein: the refrigeration cycle includes a compressor; the compressor includes an electric discharge region where electric discharge occurs and a slide region including a slide portion where a plurality of slide members slide in a state where sliding surfaces thereof are in contact with each other; and inhibiting the disproportionation reaction of the refrigerant component includes inhibiting an increase of the carbene existing in at least one of the electric discharge region or the slide region.
  7. The method according to claim 6, wherein a mole fraction of the carbene existing in at least one of the electric discharge region or the slide region is set to 0.35 or less.
  8. The method according to claim 7, wherein the increase of the carbene is inhibited by controlling a temperature in at least one of the electric discharge region or the slide region to 700 K or less.
  9. The method according to claim 7, wherein the increase of the carbene is inhibited by controlling pressure in at least one of the electric discharge region or the slide region from a high-temperature high-pressure state to 2 MPa or less.
  10. A method of capturing a carbene existing in a refrigeration cycle including a refrigeration-cycle composition, wherein in the refrigeration cycle, the refrigeration-cycle composition contains a carbonyl compound, and the carbonyl compound includes, in its chemical structure, a carbon-oxygen double bond (C=O bond) that reacts with the carbene and at least one alpha hydrogen atom, the method comprising capturing the carbene existing in the refrigeration cycle in such a manner that the carbonyl compound reacts with the carbene existing in the refrigeration cycle.
  11. A refrigeration-cycle composition comprising: a refrigerant component that causes a disproportionation reaction; and a carbonyl compound including, in its chemical structure, a carbon-oxygen double bond (C=O bond) and at least one alpha hydrogen atom.
  12. The refrigeration-cycle composition according to claim 11, wherein the carbonyl compound is propionaldehyde, acetone, cyclopropanone, acetaldehyde, or a derivative of any of these compounds which includes three carbon atoms or less.
  13. The refrigeration-cycle composition according to claim 11, wherein the carbonyl compound is aldehyde or ketone having a structure represented by Formula (1), where each of R 1 , R 2 , and R 3 is independently an atom or an atomic group selected from the group consisting of H, F, Cl, Br, I, CH 3 , CF 3 , OCH 3 , SCH 3 , and NH 2 .
  14. The refrigeration-cycle composition according to claim 11, wherein the refrigerant component is ethylene based fluoroolefin.
  15. The refrigeration-cycle composition according to claim 14, wherein the carbonyl compound is contained in an amount of 50 parts by mass or less relative to 100 parts by mass of the ethylene based fluoroolefin.
  16. The refrigeration-cycle composition according to claim 14, wherein: the carbonyl compound is aldehyde or ketone in which each R in Formula (1) above is independently an atom or an atomic group selected from the group consisting of H, CH 3 , OCH 3 , SCH 3 , and NH 2 ; and the carbonyl compound is contained in an amount of 20 parts by mass or less relative to 100 parts by mass of the ethylene based fluoroolefin.
  17. The refrigeration-cycle composition according to claim 11, wherein the carbonyl compound is 1,1,1-trifluoroacetone (CF 3 -CO-CH 3 ), 1,1,1,3,3-pentafluoroacetone (CF 3 -CO-CHF 2 ), 1,1,1,3-tetrafluoroacetone (CF 3 -CO-CH 2 F), or acetone (CH 3 -CO-CH 3 ).
  18. The refrigeration-cycle composition according to claim 11, further comprising saturated hydrocarbon.
  19. The refrigeration-cycle composition according to claim 11, comprising haloalkane including one or two carbon atoms.
  20. A refrigeration cycle apparatus comprising the refrigeration-cycle composition according to claim 11.

Description

Technical Field The present invention relates to a method of inhibiting a refrigeration-cycle working medium which can effectively inhibit or mitigate a disproportionation reaction of fluoroolefin (fluoroalkene), such as 1,1,2-trifluoroethylene, and a refrigeration-cycle working medium which uses this method. Background Art As a refrigeration-cycle working medium (a refrigerant or a heat medium), the use of fluoroolefin having an ozone depletion potential (ODP) of 0 and a lower global warming potential (GWP), especially hydrofluoroolefin (HFO), has been recently proposed. Known as representative HFOs are, for example, 1,1,2-trifluoroethylene (HFO1123) and difluoroethylene (HFO1132). The HFOs are lower in stability than conventional HFCs (hydrofluorocarbons) and the like. Therefore, the HFOs hardly remain in the atmosphere. It is also known that since the stability of the HFO is low, a self-polymerization reaction which is called a disproportionation reaction tends to occur (such reaction is hereinafter referred to as the disproportionation reaction). The disproportionation reaction tends to occur by being induced by, for example, heat generated during the use of the refrigeration-cycle working medium. In addition, it is also known that since large heat dissipation is caused by the occurrence of the disproportionation reaction, the disproportionation reactions occur successively. As a result, a large amount of soot is generated, and this may deteriorate the reliability of a refrigeration cycle system or the reliability of a compressor and the like constituting the refrigeration cycle system. The present applicants propose that when, for example, 1,1,2-trifluoroethylene is used as a refrigerant component of the refrigeration-cycle working medium, halomethanes (PTL 1), saturated hydrocarbons (PTL 2), haloethanes (PTL 3), a combination of these (PTL 4 or PTL 5), or difluoroiodomethane (PTL 6) as a representative example of an especially suitable disproportionation inhibitor is used as a component (disproportionation inhibitor) that inhibits the disproportionation reaction of the 1,1,2-trifluoroethylene. Citation List Patent Literature PTL 1: Japanese Laid-Open Patent Application Publication No. 2017-145380PTL 2: Japanese Laid-Open Patent Application Publication No. 2018-048271PTL 3: Japanese Laid-Open Patent Application Publication No. 2018-104565PTL 4: Japanese Laid-Open Patent Application Publication No. 2018-104566PTL 5: Japanese Laid-Open Patent Application Publication No. 2019-034983PTL 6: Japanese Laid-Open Patent Application Publication No. 2021-161316 Summary of Invention Technical Problem In consideration of various conditions that may affect the occurrence of the disproportionation reaction in a refrigeration cycle, PTLs 1 to 6 propose various disproportionation inhibitors and combinations thereof. These disproportionation inhibitors can effectively inhibit or mitigate the disproportionation reaction of fluoroolefin, such as 1,1,2-trifluoroethylene. However, there remain many unknown points regarding the disproportionation reaction of the fluoroolefin. Therefore, in addition to the disproportionation inhibitors proposed in PTLs 1 to 6, it is required to consider a new method that can effectively inhibit or mitigate the disproportionation reaction. The present invention was made to solve the above problem, and an object of the present invention is to provide a new method of effectively inhibiting or mitigating a disproportionation reaction of fluoroolefin in a refrigeration-cycle working medium which contains the fluoroolefin as a refrigerant component. Solution to Problem The present inventors have diligently studied to solve the above problem. As a result, the present inventors have uniquely found that: a carbonyl compound, which has not been considered at all so far in the field regarding the inhibiting of the disproportionation reaction, may contribute to the inhibiting or mitigating of the disproportionation reaction; and the carbonyl compound acts on not an active radical generated in association with the self-decomposition of the fluoroolefin but a carbene. Thus, the present invention has been made. To solve the above problem, a method of inhibiting a disproportionation reaction of a refrigeration-cycle working medium according to the present disclosure is a method of inhibiting a disproportionation reaction of a refrigeration-cycle working medium containing a refrigerant component that causes the disproportionation reaction, wherein in a refrigeration cycle in which the refrigeration-cycle working medium circulates, the refrigeration-cycle working medium contains a carbonyl compound, and the carbonyl compound includes, in its chemical structure, a carbon-oxygen double bond (C=O bond) that reacts with a carbene and at least one alpha hydrogen atom, the method including inhibiting the disproportionation reaction of the refrigerant component in such a manner that the carbonyl compound captures the