JP2009001651A - Nonflammable composition of 1,1-difluoroethane and trifluoroiodomethane having low warming potential - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerant mixture that hardly exerts influences on ozone depletion potential and global warming and yet has almost equal refrigerant properties to 1,1,1,2-tetrafluoroethane and is nonflammable. <P>SOLUTION: The nonflammable refrigerant composition comprises 1,1-difluoroethane and trifluoroiodomethane. The nonflammable refrigerant composition is composed of 20-50 mass% of 1,1-difluoroethane and 80-50 mass% of trifluoroiodomethane. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention provides a nonflammable refrigerant composition of 1,1-difluoroethane and trifluoroiodomethane,
And an HFC134a alternative refrigerant using the composition.

Conventionally, chlorofluorohydrocarbons and fluorohydrocarbons have been used as refrigerants in refrigerators and heat media in heat pumps, and these simple substances or azeotropic compositions and mixtures have been referred to as chlorofluorocarbons. However, in recent years, it has been pointed out that those chlorofluorocarbons released into the atmosphere destroy the ozone layer and have a serious adverse effect on the earth's ecosystem including humans, and there is already a high risk of ozone layer destruction. The use and production of CFCs are regulated by international agreements. Dichlorodifluoromethane (R12) has been mainly used as a refrigerant in household refrigerators, car air conditioners, turbo refrigerators, and container refrigeration equipment. However, 1,1,1,2-tetrafluoroethane (HFC134a ). However, in June 2006, two legislations (Regulation on certain fluorinated greenhouse gases) and Directive relating to emissions of f-gas form air conditioning systems fitted to cars were promulgated in June 2006. As for car air conditioners, it was obliged to use refrigerants with GWP of 150 or less for new models shipped from 2011 and all vehicles from 2017. For this reason, GWP1300 is also shown for the currently installed HFC134a, and although CO _{2 and the} like have been proposed as an alternative candidate, it has various problems such as improvement of equipment and refrigeration capacity at high temperature due to the critical fluid. ing.

In addition, i-C ₄ H ₁₀ is a refrigerant in some electric refrigerators and has a very burning power, so it has not been replaced in all fields.

  Therefore, it has low GWP, energy efficiency, refrigerant characteristics (refrigeration capacity, boiling point, pressure, nonflammability, etc.) are almost the same as 1,1,1,2-tetrafluoroethane, and there is no need for improvement of equipment, or it is light Development of a nonflammable refrigerant is desired.

1,1-difluoroethane (HFC152a) and trifluoroiodomethane (CF ₃ I)
Regarding the mixed refrigerant, there are Patent Documents 1 to 3. In patent document 1, it is described that it becomes nonflammable with a composition of 95 mass% or less. Patent Document 2 shows data in which the azeotropic point varies depending on the temperature. Patent document 3 describes that HFC152a is azeotropic at 35 to 55 mass%.
JP-A-4-323294 US2006 / 0116310 US2005 / 023392

  The main object of the present invention is that the risk of ozone destruction is close to zero, the effect on global warming is small compared to conventional HFC refrigerants, and the refrigerant characteristics are almost the same as 1,1,1,2-tetrafluoroethane. By providing a refrigerant composition useful for various applications as an alternative to the (1300) 1,1,1,2-tetrafluoroethane refrigerant with a relatively high GWP because it is equivalent and non-combustible as a refrigerant. is there.

  As a result of intensive studies in view of the above-mentioned problems, the present inventor has found that a mixture composed of 1,1-difluoroethane and trifluoroiodomethane forms a non-flammable refrigerant composition and has a property suitable for the above purpose. I found out that it was a thing.

That is, this invention provides the refrigerant | coolant thru | or alternative refrigerant | coolant which are the following nonflammable refrigerant compositions.
Item 1: A nonflammable refrigerant composition comprising 1,1-difluoroethane and trifluoroiodomethane.
Item 2: The composition according to Item 1, comprising 20% by mass to 50% by mass of 1,1-difluoroethane and 80% by mass to 50% by mass of trifluoroiodomethane.
Item 3: The composition according to Item 1, wherein 1,1-difluoroethane comprises 40 mass% to 50 mass% and trifluoroiodomethane comprises 60 mass% to 50 mass%.
Item 4: The composition according to any one of Items 1 to 3, further comprising 0.1 to 10 parts by weight of a stabilizer relative to 100 parts by weight of the total amount of 1,1-difluoroethane and trifluoroiodomethane. object.
Item 5: An HFC134a alternative refrigerant comprising the composition according to any one of Items 1 to 4.
Item 6: The alternative refrigerant according to Item 5, for use in any of a mobile air conditioner, a refrigerator, a turbo refrigerator, and a container refrigeration apparatus.

The composition of the present invention has the following excellent characteristics.
(1) Since it does not contain chlorine or bromine, it has little danger of destroying the ozone layer even if released into the atmosphere, and its global warming potential is small, and its impact on global warming is 1,1,1. , 2-tetrafluoroethane is about 1/10 or less.
(2) Refrigerant performance such as refrigeration capacity is almost equivalent to 1,1,1,2-tetrafluoroethane (3) CF ₃ I has a flame-extinguishing action, and the composition mixed with HFC152a is It becomes a nonflammable mixture.

1,1-Difluoroethane (HFC152a) used in the present invention is a compound having the following characteristics, has no danger of destroying the ozone layer, and has a global warming potential (GWP) of 120 when CO ₂ is 1. Yes, about 1/10 of 1,1,1,2-tetrafluoroethane compared to GWP1300, which has very little adverse effect on global warming, but has a combustion range (4.4 to 17.5 vol%) It is a flammable high pressure gas.
(HFC152a)
Molecular formula: CF ₂ HCH ₃
Molecular weight; 66
Boiling point: -24.0 ° C
GWP; 120

In addition, trifluoroiodomethane is a compound having the following characteristics and does not contain any chlorine and bromine atoms that affect the ozone layer. It is a nonflammable high-pressure gas having a gasification coefficient (GWP) of 5 or less and having very little adverse effect on global warming.
(Trifluoroiodomethane)
Molecular formula; CF ₃ I
Molecular weight; 196
Boiling point: -22.5 ° C
GWP; <5

  The inventor has intensively studied the relationship between the mixing ratio of 1,1-difluoroethane having a combustion range and trifluoroiodomethane, which is incombustible, and flammability. The combustibility was carried out by a method according to the ASHRAE method (10 L, spherical flask, discharge ignition, measurement temperature 60 ° C.). The ASHRAE method is described in ASHRAESTANDARD 34-2001 ASTM Designation; E681.

As a result of the measurement, it was found that in the mixed gas of HFC-152a + CF ₃ I, non-flammability is exhibited if CF ₃ I is mixed at a mass ratio of 59% by mass or more of HFC-152a and CF ₃ I.

In the ASHRAE method, the risk of the leaked gas composition of the mixed gas is used as a criterion for judgment, and the boiling point + 10 ° C. and −40 ° C. of the mixed gas are compared, and the leak composition due to the higher temperature is determined by combustion. In the mixed system of HFC152a + CF ₃ I, the evaluation is based on the leakage gas composition at the boiling point + 10 ° C.

When the filling composition of HFC152a / CF ₃ I is 50/50 mass%, the boiling point + 10 ° C. is −1.
The gas phase composition at that temperature is HFC152a / CF ₃ I = 40.3 /
59.7 mass% is shown. Therefore, when the mass ratio of CF ₃ I is 50% or more in the filling composition of HFC152a / CF ₃ I, it was found that the refrigerant composition exhibits nonflammability in the determination of the ASHRAE method.

This result is inconsistent with the description that CF ₃ I described in Patent Documents 1 to ₃ is 5 mass% or more and is nonflammable.

In Patent Document 1, the measurement method and criteria are not described, and the reason why they do not agree is unclear. However, at least in the mixed composition of HFC152a / CF ₃ I, HFC152a is combustible over a range of 41 to 95 mass%. It was found that this is not consistent with Patent Document 1.

Even if HFC152a, which is the combustible range composition clarified in the present invention, is larger than 41 mass%, if HFC152a is about 50 mass% or less as a liquid phase composition, the gas phase composition becomes 40 mass% and becomes nonflammable as a refrigerant. I understood that. In Patent Documents 2 and 3, this liquid phase composition range is described as being azeotropic, but there is no description regarding combustibility.
Further, even if it is known that HFC152a exhibits flammability in a composition range greater than 41 mass%, Patent Document 3 states that HFC152a exhibits azeotropic behavior at 35 to 55 mass%, so that the gas phase composition is a liquid phase composition. In other words, there was a suspicion that the liquid phase composition of HFC152a was flammable at 41 to 55 mass%.

The mixing composition of HFC152a and CF ₃ I is characterized in refrigeration capacity, in proportion to the CF ₃ I amount by mixing a low refrigerating capacity CF ₃ I with high normal refrigeration capacity HFC152a, refrigerating capacity is Although the value was low, it was found that the HFC152a / CF3I = 40/60 mass% composition showed a maximum value, which was equivalent to or higher than that of 1,1,1,2-tetrafluoroethane (HFC134a).

  Although the nonflammable refrigerant composition of the present invention exhibits high stability, a stabilizer can be added as necessary when high stability is required under severe use conditions. Such stabilizers include (i) aliphatic nitro compounds such as nitromethane and nitroethane, aromatic nitro compounds such as nitrobenzene and nitrostyrene, (ii) ethers such as 1,4-dioxane, 2,2,3 1,3,3-pentafluoropropylamine, amines such as diphenylamine, butylhydroxyxylene, benzotriazole and the like.

The stabilizer contains at least one compound selected from (i), and may optionally be mixed with at least one compound selected from (ii).

Although the usage-amount of a stabilizer changes with kinds of stabilizer, it is set as the grade which does not have trouble in the property of a nonflammable refrigerant composition. Usually, the amount of the stabilizer used is preferably about 0.1 to 10 parts by weight, preferably about 0.1 to 5 parts by weight with respect to 100 parts by weight of the mixture of 1,1, -difluoroethane and trifluoroiodomethane. More preferably.

  The non-combustible refrigerant composition of the present invention can be used for various applications such as refrigerants, heat transfer media, working fluids, foaming agents, etc. as in the case of conventional chlorofluorocarbons, and in particular, air conditioners, refrigerators, refrigerators, car air conditioners. It is useful as a refrigerant for various other low-temperature equipment such as container refrigeration equipment.

Hereinafter, the present invention will be described in more detail with reference to examples.
Example 1
The mixture of HFC152a and trifluoroiodomethane of various compositions is operated with the evaporation temperature of the heat medium in the evaporator set to 5 ° C, the condensation temperature in the condenser set to 45 ° C, the degree of superheat, and the degree of supercooling of 0 ° C. Asked. The results are shown in Table 1 below and FIG.

Comparative Example 1
As a comparative example, HFC134a was also operated under the same conditions as in Example 1 to determine the refrigeration capacity. The results are shown in Table 1.

From the above results, the inventors in HFC152a / CF ₃ mixture specific composition range of I (HFC152a / CF3I = 40~50 / 50~60mass%, greater than the height of the refrigerating capacity which is characteristic of HFC152a and of HFC134a It has been found that the refrigerant performance (pressure and refrigeration capacity) is higher than that, and exhibits non-flammability, which is a feature of CF ₃ I, and satisfies the GWP value of 150 or less, which is the standard value of the F gas regulations of EP. As a substitute, it is possible to provide a gas mixture that is friendly to the global environment.

The result of having calculated | required the refrigerating capacity about the mixture of HFC152a and trifluoroiodomethane of various compositions is shown.

Claims (6)

A nonflammable refrigerant composition comprising 1,1-difluoroethane and trifluoroiodomethane. The composition according to claim 1, comprising 20 mass% to 50 mass% of 1,1-difluoroethane and 80 mass% to 50 mass% of trifluoroiodomethane. The composition according to claim 1, wherein 1,1-difluoroethane comprises 40 mass% to 50 mass% and trifluoroiodomethane comprises 60 mass% to 50 mass%. The composition according to any one of claims 1 to 3, further comprising 0.1 to 10 parts by weight of a stabilizer with respect to 100 parts by weight of the total amount of 1,1-difluoroethane and trifluoroiodomethane. An HFC134a alternative refrigerant comprising the composition according to any one of claims 1 to 4. The alternative refrigerant according to claim 5 for use in any one of a mobile air conditioner, a refrigerator, a turbo refrigerator, and a container refrigeration apparatus.

Images