JPH05140546A - Refrigeration medium composed of nonafluorobutane - Google Patents

Abstract

PURPOSE:To provide a readily decomposable refrigeration medium composed of nonafluorobutane, free from destruction of ozone layer, excellent in incombustibility and thermal stability and useful for refrigerator use, etc. CONSTITUTION:The objective refrigeration medium is composed of a nonafluorobutane such as CF3CF2CF2CHF2 or (CF3)3CH. In addition, e.g. CF3CF2 CF2CHF2 has following physical properties; boiling point: 14 deg.C; latent heat of vaporization: 28.5 Kcal/kg (at 0 deg.C); critical temperature: 139 deg.C; coefficient of ozone layer destruction: 0.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel refrigerant.

[0002]

2. Description of the Related Art Conventionally, as working fluids or refrigerants, chlorofluoroalkanes, azeotropic compositions thereof, and compositions having compositions in the vicinity thereof have been known. Of these, CFC11 is currently used as a working fluid for refrigerators.
(Trichlorofluoromethane), CFC12 (dichlorodifluoromethane), CFC114 (1,2-dichloro-1,1,2,2-tetrafluoroethane) and the like are mainly used. However, in recent years, when released to the atmosphere, these chlorofluoroalkanes rise to the stratosphere because it takes a long time to decompose,
Therefore, it is pointed out that chlorine radicals generated by decomposition destroy the ozone layer in the stratosphere, resulting in serious adverse effects on the earth's ecosystem including humans. Therefore, use and production of these chlorofluoroalkanes, which have a high possibility of depleting the ozone layer, have been limited by international agreements. The chlorofluoroalkanes currently subject to restrictions include R11 and R1 above.
2, R114, etc.

With the spread of air-conditioning and refrigerating equipment, the demand for these refrigerants is increasing every year, and the restrictions on the use and production of these refrigerants include the living environment and the storage and transportation of food products.
Since it has a great impact on current social mechanisms in general, development of a new refrigerant having no or very low risk of ozone depletion is an urgent issue.

Promising compounds that can substitute for the above-mentioned chlorofluoroalkanes (hereinafter referred to as alternative candidate compounds) are chlorofluoroalkanes or fluoroalkanes containing hydrogen atoms, such as HCFC21 (dichloromonofluoromethane), HFC23 ( Trifluoromethane), HFC32 (difluoromethane), HCFC12
3 (dichlorotrifluoroethane), HCFC124
(Monochlorotetrafluoromethane), HFC125
(Pentafluoroethane), HCFC133a (monochlorotrifluoroethane), HFC134a (tetrafluoroethane), HCFC142b (monochlorodifluoroethane), HFC143a (trifluoroethane)
And so on.

However, these alternative candidate compounds do not satisfy all the ozone depletion potential (hereinafter referred to as ODP), nonflammability, and other various performances required as a refrigerant. For example, HCFC123 has a much lower ODP than the above-mentioned regulated compounds (for example, about 1/50 of CFC11), so HCFC123 is not regulated, but it may be more toxic than CFC11. It is desirable that a compound having zero ODP be substituted.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a refrigerant which has low toxicity to the human body, zero ODP, excellent performance as a refrigerant, and which is substantially free of composition change during phase change during equipment operation. The main purpose is to provide.

[0007]

The present inventors have conducted various studies in view of the current state of the art as described above. As a result, they have found that the refrigerant consisting of nonafluorobutane has the requirements meeting the purpose.

That is, the present invention provides a refrigerant comprising nonafluorobutane.

The refrigerant made of nonafluorobutane used in the present invention means CF ₃ CF ₂ CF ₂ CHF ₂ and CF ₃ C.
HFCF ₂ CF ₃ , (CF ₃ ) ₃ CH and (CF ₃ )
_{2 A} refrigerant consisting of one or more of CFCHF ₂ is meant. All of the nonafluorobutanes used in the present invention are known compounds and can be produced by a conventional method.

The main physical properties of the above four kinds of nonafluorobutane used in the present invention are as shown in Table 1 below. Table 1 Cooling medium CF ₃ CF ₂ CF ₂ CHF ₂ Molecular weight 220 Boiling point (° C) 14 Latent heat of vaporization (kcal / kg: 0 ° C) 28.5 Critical temperature (° C) 139 Ozone depletion potential 0 Table 1 (continued) Cooling medium ( CF ₃ ) ₃ CH molecular weight 220 Boiling point (° C) 12 Latent heat of vaporization (kcal / kg: 0 ° C) 27.6 Critical temperature (° C) 136 Ozone depletion potential 0 Table 1 (continued) Cold medium CF ₃ CHFCF ₂ CF ₃ Molecular weight 220 Boiling point (° C) 5 Latent heat of vaporization (kcal / kg: 0 ° C) 26.3 Critical temperature (° C) 126 Ozone depletion potential 0 Table 1 (continued) Cold medium (CF ₃ ) ₂ CFCHF ₂ Molecular weight 220 Boiling point (° C) 13 Evaporation Latent heat (kcal / kg: 0 ℃) 27.8 Critical temperature (℃) 137 Ozone depletion potential 0

If desired, a stabilizer may be used in combination with the refrigerant of the present invention. That is, when a high degree of stability is required under severe conditions of use, epoxides such as propylene oxide, 1,2-butylene oxide and glycidol; phosphites such as dimethylphosphite, diisopropylphosphite and diphenylphosphite. Phites; thiophosphites such as trilauryltrithiophosphite; phosphine sulfides such as triphenoxyphosphine sulfide and trimethylphosphine sulfide; boron compounds such as boric acid, triethylborate, triphenylborate, phenylboronic acid and diphenylboronic acid Phenols such as 2,6-di-tert-butylparacresol; nitromethane;
Nitroalkanes such as nitroethane; acrylic acid esters such as methyl acrylate and ethyl acrylate; other dioxane, tert-butanol, pentaerythritol, paraisopropenyltoluene; It can be added.

Further, other compounds can be mixed with the refrigerant of the present invention within a range not impairing the objects and effects of the present invention. Examples of such compounds include ethers such as dimethyl ether and pentafluorodimethyl ether; amines such as perfluoroethylamine; LPG and the like.

[0013]

INDUSTRIAL APPLICABILITY The nonafluorobutane used in the present invention is easily decomposable and does not contain a chlorine atom that affects the ozone layer. Therefore, the ODP is zero and the risk of ozone layer depletion is low. Absent. CF ₃ CF ₂ CF of the present invention
_The refrigerant composed of ₂ CHF ₂ or the refrigerant composed of (CF ₃ ) ₃ CH exhibits a refrigerating capacity higher than that of CFC11 by about 10 to 20%, and exhibits an overall excellent performance that the coefficient of performance is about the same. Therefore, the CFC 11 used as a turbo refrigerant or the like can be substituted. Since the refrigerant according to the present invention is composed only of nonafluorobutane, liquid management and reuse after recovery can be advantageously performed. Since the refrigerant according to the present invention has low solubility in polymer compounds,
Without changing the material in the existing refrigerator,
It can be used as it is. The refrigerant according to the present invention is a PAG.
Excellent compatibility with (polyalkylene glycol) -based oils and polyester-based oils. The refrigerant according to the present invention is nonflammable and has good thermal stability.

[0015]

EXAMPLES Examples and comparative examples will be shown below to further clarify the features of the present invention.

Example 1 Among the refrigerants according to the present invention, CF ₃ CF ₂ CF ₂ CHF
_{2 In} a 1-horsepower refrigerator using (refrigerant A) and (CF ₃ ) ₃ CH (refrigerant B), the evaporation temperature of the refrigerant in the condenser was set to 5 ° C, the condensation temperature was set to 40 ° C, and the compressor inlet was overheated. The temperature is set to 12 ° C and the degree of supercooling at the condenser outlet is set to 5
The operation was carried out at 0 ° C. Polyalkylene glycol was used as the refrigerating machine oil. Table 2 shows the coefficient of performance (CO
P), refrigerating capacity [kcal / m ³ ] and compressor gas discharge temperature (° C) are shown. Table 2 also shows CFC1 as a comparison.
The results for 1 are also shown. Table 2 Coolant COP Refrigeration capacity Compressor gas discharge (kcal / m ³ ) Temperature (° C) Refrigerant A 7.0 151 40 Refrigerant B 7.0 160 40 (CFC11) 7.3 130 52 From the results shown in Table 2, It is clear that the refrigerant of the present invention has comprehensively balanced properties compared to CFC11.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuji Fujiwara No. 1 Nishiichitsuya, Settsu City, Osaka Prefecture Daikin Industries, Ltd. Yodogawa Manufacturing Co., Ltd. (72) Hiroshi Momota No. 1 Nishiichitsuya, Settsu City, Osaka Prefecture Daikin Industries, Ltd. Yodogawa Manufacturing Co., Ltd.

Claims (3)

[Claims] 1. A refrigerant comprising nonafluorobutane. 2. The refrigerant according to claim 1, comprising CF ₃ CF ₂ CF ₂ CHF ₂ . 3. The refrigerant according to claim 1, which comprises (CF ₃ ) ₃ CH.