Composition for heat cycle system, and heat cycle system

1. A composition for a heat cycle system, which comprises a working fluid for heat cycle containing trifluoroethylene, and a radical scavenger, wherein the radical scavenger is methylene chloride.

2. The composition for a heat cycle system according to claim 1 , wherein said composition further comprises at least one additional radical scavenger selected from the group consisting of a thioether compound, an aromatic amine compound having active hydrogen, a nitroso compound, a hydroxy aromatic compound, a quinone compound, a transition metal salt, an agent for generating a halogen atom other than fluorine, and a perfluoroalkyl radical generator.

3. The composition for a heat cycle system according to claim 2 , wherein said composition further comprises at least one additional radical scavenger selected from the group consisting of phenothiazine, distearyl thiodipropionate, p-phenylenediamine, 4-aminodiphenylamine, N,N′-diphenyl-p-phenylenediamine, N-isopropyl-N′-phenyl-p-phenylenediamine , N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, N,N′-di-2-naphthyl-p-phenylenediamine, diphenylamine, N-phenyl-β-naphthylamine, 4,4′-dicumyl-diphenylamine, 4,4′-dioctyl-diphenylamine, N-nitrosodiphenylamine, N-nitrosophenylnaphthylamine, N-nitrosodinaphthylamine, p nitrosophenol, nitrosobenzene, p-nitrosodiphenylamine, α-nitroso-β-naphthol, hydroquinone, allylphenol, 4,6-dimethyl-2-allylphenol, p-methoxyphenol, cresol, t-butylcatechol, 3,5-di-t-butyl-4-hydroxytoluene, 2,2′-methylenebis(4-methyl-6-t-butylphenol), 2,2′-methylenebis(4-ethyl-6-butylphenol), 4,4′-thiobis(3-methyl-6-t-butylphenol), copper dialkyldithiocarbamate (wherein each of the alkyl groups which may be the same or different from each other, is a methyl group, an ethyl group, a propyl group or a butyl group (provided that the propyl group or the butyl group may be branched)), copper acetate, copper salicylate, copper thiocyanate, copper nitrate, copper chloride, copper carbonate, copper hydroxide, copper acrylate, manganese dialkyldithiocarbamate (wherein each of the alkyl groups which may be the same or different from each other, is a methyl group, an ethyl group, a propyl group or a butyl group (provided that the propyl group or the butyl group may be branched)), manganese diphenyldithiocarbamate, manganese formate, manganese acetate, manganese octanoate, manganese naphthenate, manganese permanganate, manganese salt of ethylenediaminetetraacetic acid, a compound having a C—X (wherein X is Cl, Br or I) bond and having the C—X bond energy being at most the other bond energies in its molecule, CX 4 (wherein X is Cl, Br or I, and four Xs are the same) and Rf—X (wherein Rf is a C 1-6 perfluoroalkyl group, and X is Cl, Br or I).

4. The composition for a heat cycle system according to claim 3 , wherein said composition further comprises at least one additional radical scavenger selected from the group consisting of a compound having a C—X (wherein X is Cl, Br or I) bond and having the C—X bond energy being at most the other bond energies in its molecule, CX 4 (wherein X is Cl, Br or I, and four Xs are the same) and Rf—X (wherein Rf is a C 1-6 perfluoroalkyl group, and X is Cl, Br or I).

5. The composition for a heat cycle system according to claim 1 , wherein said composition further comprises α-pinene.

6. The composition for a heat cycle system according to claim 1 , wherein said composition further comprises CH 3 F.

7. The composition for a heat cycle system according to claim 1 , wherein the content of the radical scavenger is from 1 to 10 parts by mass per 100 parts by mass of HFO-1123 in the composition.

8. The composition for a heat cycle system according to claim 1 , wherein the working fluid for heat cycle further comprises at least one member selected from a saturated hydrofluorocarbon.

9. The composition for a heat cycle system according to claim 8 , wherein the saturated hydrofluorocarbon is at least one member selected from difluoromethane, 1,1-difluoroethane, 1,1,1,2-tetrafluoroethane and pentafluoroethane.

10. The composition for a heat cycle system according to claim 1 , wherein the working fluid for heat cycle further comprises at least one member selected from a hydrofluorocarbon having a carbon-carbon double bond other than trifluoroethylene.

11. The composition for a heat cycle system according to claim 10 , wherein the hydrofluorocarbon having a carbon-carbon double bond is at least one member selected from 1,3,3,3-tetrafluoropropene and 2,3,3,3-tetrafluoropropene.

12. The composition for a heat cycle system according to claim 1 , wherein the proportion of trifluoroethylene is at least 20 mass % based on the working fluid for heat cycle.

13. The composition for a heat cycle system according to claim 1 , wherein the proportion of trifluoroethylene is from 20 to 80 mass % based on the working fluid for heat cycle.

14. A heat cycle system, which employs the composition for a heat cycle system as defined in claim 1 .

15. The heat cycle system according to claim 14 , which is a refrigerating apparatus, an air-conditioning apparatus, a power generation system, a heat transport apparatus or a secondary cooling machine.

16. The composition for a heat cycle system according to claim 1 , further comprising an agent for generating a halogen atom other than fluorine, which is a compound having a C—X bond, wherein X is Cl, Br or I, and having the C—X bond energy being at most the other bond energies in its molecule, or CX 4 , wherein X is Cl, Br or I and four Xs are the same.

17. The composition for a heat cycle system according to claim 1 , further comprising an additional radical scavenger which is a C 1-4 linear or branched hydrocarbon compound which optionally have a double bond, in which at least one and at most, the total number of the C—H bond, the C—C bond and the C═C bond—1, C—H bonds are substituted by a C—X bond, wherein X is Cl, Br or I bond, or CX 4 , wherein X is Cl, Br or I, and four Xs are the same.

18. The composition for a heat cycle system according to claim 1 , further comprising at least one additional radical scavenger selected from the group consisting of CH 3 Br, CH 3 Cl, CH 2 Br 2 ,CHBr 3 , CHCl 3 , CCl 4 , CH 3 CH 2 I, CH 3 CH 2 Br, CH 3 CH 2 Cl, CH 2 BrCH 2 Br, CH 2 ClCH 2 Cl, CH 3 CHCl 2 , CH 3 CCl 3 , CH 3 CHClCH 2 Cl, CH 2 ClCHClCH 2 Cl, CHCl═CCl 2 , CCl 2 ═CCl 2 , CH 3 CH 2 CH 2 I, CH 3 CH 2 CH 2 Br, CH 3 CH 2 CH 2 Cl, CH 3 CH 2 CH 2 CH 2 I, CH 3 CH 2 CH 2 CH 2 Br, CH 3 CH 2 CH 2 CH 2 Cl, CH 2 ═CHCH 2 I, CH 2 ═CHCH 2 Br, CH 2 ═CHCH 2 Cl, (CH 3 ) 3 CI, (CH 3 ) 3 CBr and (CH 3 ) 3 CCl.

19. The composition for a heat cycle system according to claim 1 , further comprising at least one additional radical scavenger selected from the group consisting of CH 3 Br, CH 3 Cl, CH 2 Br 2 , CHBr 3 , CHCl 3 , CCl 4 , CH 3 CH 2 I, CH 3 CH 2 Br, CH 3 CH 2 Cl, CH 2 BrCH 2 Br, CH 2 ClCH 2 Cl, CH 3 CHCl 2 , CH 3 CCl 3 , CHCl═CCl 2 , CCl 2 ═CCl 2 , CH 3 CH 2 CH 2 I, CH 3 CH 2 CH 2 Br, CH 3 CH 2 CH 2 Cl, CH 3 CH 2 CH 2 CH 2 I, CH 3 CH 2 CH 2 CH 2 Br, CH 3 CH 2 CH 2 CH 2 Cl, CH 2 ═CHCH 2 I, CH 2 ═CHCH 2 Br, CH 2 ═CHCH 2 Cl, (CH 3 ) 3 Cl, (CH 3 ) 3 CBr and (CH 3 ) 3 CCl.