JPH041289A - Refrigerant - Google Patents

Abstract

PURPOSE:To obtain a refrigerant which can prevent ozonosphere destruction when released in the air by mixing 1-chloro-2,2,2-trifluoroethane and 1,1,2- trifluoroethane. CONSTITUTION:A mixture of 99-20mol% 1-chloro-2,2,2-trifluorethane and 1-80mol% 1,1,2-trifluoroethane is mixed, if necessary, with 0.01-5wt.% stabilizing agent (e.g. propylene oxide).

Description

[Detailed description of the invention] Industrial applications The present invention relates to refrigerants.

Conventional technology and its problems Conventionally, as working fluids or refrigerants, chlorofluoro compounds,
These azeotropic compositions and compositions in the vicinity thereof are known. Among these, R-11 (dichlorofluoromethane), R-
12 (dichlorodifluoromethane), R-114 (1
, 2-dichloro-1,1,2,2-tetrafluoroethane) and the like are mainly used. However, in recent years,
When released into the atmosphere, certain chlorofluorocarbons that do not contain hydrogen take a long time to decompose, rising to the stratosphere where they decompose and deplete the stratospheric ozone layer, resulting in It has been pointed out that this has a serious negative impact on the earth's ecosystem, including humans.

Therefore, the use and production of these hydrogen-free chlorofluorocarbons, which are highly likely to cause ozone layer depletion, are being restricted by international agreements.

The above-mentioned hydrogen-free chlorofluorocarbons subject to restrictions include the above-mentioned R-11, R-12, and R-1.
There are 14 etc. Hydrogen-containing chlorofluorocarbons such as R-22 are also often used in refrigeration and air conditioning applications, but they have a rather low boiling point and have the disadvantage of being too high in pressure, especially in the air conditioning field for high-temperature applications. Restrictions on the use and production of these refrigerants, whose demand is increasing every year with the spread of refrigeration and air-conditioning equipment, have a large impact on the living environment and current social institutions in general, so there is a risk of ozone depletion. The development of new refrigerants that have no or very low risk of refrigerants is an urgent issue.

Means for Solving the Problems The inventor of the present invention sought to find a refrigerant suitable for refrigeration and air conditioning used in high-temperature environments (outside temperature of 35°C or higher), and naturally Various research efforts have been made in order to find a new refrigerant that does not destroy the ozone layer or only slightly destroys the ozone layer even when As a result, 1
-chloro-2,2゜2-trifluoroethane and 1,
It has been found that a mixture of 1,2-trifluoroethane meets the requirements for that purpose.

That is, the present invention relates to a refrigerant consisting of a mixture of 1-chloro-2,2,2-trifluoroethane and 1.1.2-trifluoroethane.

The main physical properties of 1-chloro-2,2,2-trifluoroethane (hereinafter referred to as R-133a) used in the present invention are as follows.

Boiling point 6.1℃ Critical temperature 155℃ Molecular weight 118.49 Flammability None Meanwhile, the main physical properties of 1,1,2-trifluoroethane (hereinafter referred to as R-143) used in combination with R-133a are as follows. It is.

Boiling point: 5°C Critical temperature: 158°C Molecular weight: 84.04 Flammability Yes If a mixture of R-133a and R-143 exhibits azeotropic properties, it would be extremely advantageous in handling when used as a refrigerant. was found not to be azeotropic.

However, since the vapor pressures of the two at each temperature are close to each other, when this mixture is actually used as a refrigerant, it has the advantage of being able to be treated almost in the same way as an azeotrope across all mixing ratios. There was found.

In the present invention, the mixing ratio of R-133a and R-143 is the molar ratio of the former: the latter = 99 to 20: 1 to 80.
The ratio is preferably 60-30:40-70. From the viewpoint of whether the mixed refrigerant has nonflammable properties, it is desirable that the proportion of R-133a be at least 20% or more in terms of molar ratio. Compared to R-133a, R-143 has a larger refrigerating capacity for the same piston displacement area, and the mixture of both has the highest refrigeration capacity when the molar ratio of R-133a is 45%. Since it exhibits a coefficient of performance of (see Table 1 below), it can be said that a blending molar ratio of around ±15% around this is preferable. If the proportion of R-143 in 100 moles of the mixture is less than 1 mol%, the refrigerant capacity exhibited is 7% or more lower than that of R-114 when used as a substitute refrigerant for R-114. This is not desirable because it will result in On the other hand, when the proportion of R-143 exceeds 80 mol%,
Since the refrigerant becomes flammable, there are many disadvantages in terms of system design, which is also undesirable.

A stabilizer can be used in combination with the refrigerant of the present invention, if necessary. That is, when a high degree of stability is required under harsh usage conditions, epoxides such as propylene oxide, 1,2-butylene oxide, and glycidol; phosphors such as dimethyl phosphite, diisopropylphosphite, and diphenyl phosphite are phytes; thiophosphites such as trilauryl trithiophosphite; phosphine sulfides such as triphenoxyphosphine sulfide and trimethylphosphine sulfide; boron such as boric acid, triethylborate, triphenylborate, phenylboronic acid, and diphenylboronic acid Compounds; Phenols such as 2,6-di-tert-butyl para-cresol; Nitroalkanes such as nitromethane and nitroethane; Acrylic acid esters such as methyl acrylate and ethyl acrylate; Other dioxane,
Stabilizers such as tert-butanol, pentaerythritol, and barisopropenyltoluene can be added in an amount of about 0.01 to 5% of the weight of the working fluid.

Further, other compounds may be mixed with the mixture of the present invention within a range that does not impair the purpose or effect of the present invention. Examples of such compounds include ethers such as dimethyl ether and pentafluorodimethyl ether; amines such as perfluoroethylamine; and LPG.

Effects of the Invention The mixed refrigerant according to the present invention is easily decomposable and contains only a small amount of chlorine atoms that affect the ozone layer, so there is almost no risk of causing the problem of ozone layer destruction.

Furthermore, as is clear from Table 1 below, the refrigerant according to the present invention is superior to R-114, which is currently used as a refrigerant for cab coolers, in terms of coefficient of performance.
Also, although it varies depending on the mixing ratio, it is generally superior in cooling capacity, and in terms of performance such as discharge gas temperature,
Balanced.

Further, since the refrigerant according to the present invention has low solubility in high molecular compounds, it can be used as is without changing the materials in existing refrigerators.

Furthermore, the refrigerant of the present invention has excellent thermal stability and is nonflammable or slightly flammable, so it can be used as is in ordinary refrigerators.

Furthermore, the refrigerant according to the present invention has R-133a of 50
If it is more than mol%, it does not show compatibility with mineral oil.

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

Example 1 In a 1 horsepower refrigerator using R-143 and/or R-133a as a refrigerant, the evaporation temperature of the refrigerant in the condenser was 5°C, the condensation temperature was 75°C, and the superheating temperature was 5°C, The operation was performed with the degree of supercooling of the condenser being 2°C.

Table 1 shows refrigerant composition (mol%), (I) coefficient of performance and (
II) Shows the relationship between refrigeration capacity [kcal/m3].

Note that Table 1 also shows the results when R-114 was used for comparison.

Table 1 2.78 2.91 2.99 3.03 3.06 3.0B 3.05 3.03 3.00 2.96 2.91 2.48 From the results shown in Table 1, The refrigerant according to the invention is superior. It is clear that it has certain characteristics.

(Hereafter Up)

Claims (1)

[Claims] (1) A refrigerant consisting of a mixture of 1-chloro-2,2,2-trifluoroethane and 1,1,2-trifluoroethane.