KR100497468B1 - Refrigerant compositions - Google Patents

Abstract

(a) pentafluoroethane, octafluoropropane, trifluoromethoxydifluoromethane or hexafluoro-cyclopropane, or a mixture of two or more thereof in an amount of 5 to 60% by weight, based on the weight of the composition,

(b) pentafluoroethane, 1,1,1,2- or 1,1,2,2-tetrafluoroethane, 1,1-difluoroethane, trifluoromethoxypentafluoroethane, 1, 1,1,2,3,3,3-heptafluoropropane or 1,1,1,2,2,3,3-heptafluoropropane, or a mixture of two or more thereof, from 30 to 30, based on the weight of the composition An amount of 94% by weight, and

(c) an unsubstituted hydrocarbon of formula C _n H _m , wherein n is at least 4 and m is at least 2 n-2, but not methyl propane, in an amount of 1 to 10% by weight, based on the weight of the composition Refrigerant compositions are described.

Description

Refrigerant composition {REFRIGERANT COMPOSITIONS}

The present invention relates to a refrigerant composition, in particular a refrigerant composition for use as a replacement in refrigeration plants which are currently using or designed to be used.

Refrigerant R12 (CCl ₂ F ₂ ) is a refrigerant commonly used in domestic refrigerators. However, R12 contains chlorine atoms and has been implicated in environmental damage to the ozone layer. As a result, efforts have been made to replace R12 with refrigerant formulations that do not involve the use of refrigerants such as R12 containing chlorine atoms. Similar comments apply to R22, which is used especially for air conditioning systems.

As an alternative, R134a (C ₂ H ₂ F ₄ ; 1,1,1,2-tetrafluoroethane) has received particular attention with pentafluoroethane (R125) (boiling point -48.6 ° C.). Commercial formulations of these two refrigerants involve the use of hydrocarbons, ie propane, propylene or isobutane. These refrigerant formulations are generally effective as R12 and R22 replacements, but nonetheless have been found to be completely unsatisfactory.

Difficulties are associated with the flammability of the fractionated composition, ie the vapor on the liquid composition has flammability problems. As a result, such commercial formulations can produce flammable compositions under some leak scenario conditions. The flammability of these refrigerant compositions is in their hydrocarbon content. One of the purposes of hydrocarbon incorporation is to be compatible with lubricants commonly used in R12 and R22 refrigeration plants. Certain hydrocarbons are selected because they have the correct boiling point with respect to the fluorocarbon boiling point.

Surprisingly, according to the invention, it has been found that the flammability of fractionated compositions is greatly reduced when hydrocarbons having at least 4 carbon atoms other than methyl propane (isobutane) are used instead of those previously advocated. This result is surprising because, for example, n-butane has a significantly higher boiling point (-0.5 ° C) than isobutane (-11.7 ° C) and is therefore less volatile. In fact, U.S. The National Institute of Standards & Technology (NTST) computer programs REFPREP and REFLEAK were expected to be flammable when it was found that these particularly preferred n-butane-containing formulations were not flammable. Moreover, there may be a significant boiling range between the lowest boiling component and the hydrocarbons of the composition, but the temperature slide of the blend is relatively small. In certain embodiments, although the boiling point range is 36.2 ° C., the temperature slide is only 3.9 K at a boiling point of −34.6 ° C., 1 atmosphere. Even more surprising is that such formulations have reduced flammability, for example, because n-butane has a greater range of flammability limits than isobutane. Thus, n-butane has a flammability range of 1.5 to 10.1% v / v while for isobutane it is only 1.7 to 9.7% v / v.

According to the invention,

(a) R125, R218 (octafluoropropane; boiling point -36.7 ° C), trifluoromethoxy-difluoromethane (boiling point -34.6 ° C) or hexafluoro-cyclopropane (boiling point -31.5 ° C), or Two or more mixtures in an amount of 5 to 60% by weight, based on the weight of the composition,

(b) R125, R134a, R134 (1,1,2,2-tetrafluoroethane), 1,1-difluoroethane (R152a; boiling point -24.7 ° C), trifluoromethoxypentafluoroethane (boiling point) -23.3 ° C), 1,1,1,2,3,3,3-heptafluoropropane (R227ea; boiling point -18.3 ° C) or 1,1,1,2,2,3,3-heptafluoropropane (R227ca; boiling point −16.3 ° C.), or a mixture of two or more thereof in an amount of 30 to 94 wt%, based on the weight of the composition, and

(c) an unsubstituted hydrocarbon of formula C _n H _m , wherein n is at least 4 or 5 and m is at least 2 n-2, but not methyl propane, in an amount of 1 to 10% by weight, based on the weight of the composition Wherein component (b) is not pentafluoroethane and component (a) is pentafluoroethane in an amount of 30 to 60% by weight, or component (a) is octafluoropropane and component (b) is 50 There is provided a refrigerant composition present in an amount of from 94% by weight.

The present invention also provides a freezing method comprising the step of condensing the composition of the invention and then evaporating near the object to which the composition is to be cooled. The present invention also provides a refrigerating device containing the composition of the present invention as a refrigerant.

Component (c) is 1 to 10% by weight of the composition, especially 1 to 8% by weight, preferably 2 to 6% by weight, more preferably 2 to 5% by weight, especially 3 to 4% by weight, most preferably It is present in an amount of about 3.5% by weight.

It will be appreciated that both component (a) and component (b) can be R125. In this situation, the composition can thus be bicomponent and the amount of R125 will be from 90 to 99% by weight. In all other situations, the composition will be at least ternary.

Preferred compositions of the present invention are those containing one or more of R125, R134a and R218. Thus, component (a) preferably comprises R125 and / or R218 while component (b) preferably comprises R125 and / or R134a.

The presence of R218 (boiling point −36.7 ° C.) is particularly useful when the only other fluorocarbon is R134a. In this situation, R218 is particularly present in an amount of from 5 to 20% by weight, in particular from 5 to 15% by weight, more preferably from 7 to 12% by weight of the composition.

Component (a) is present in an amount of 5 to 60% by weight, generally 5 to 50% by weight. If R125 does not constitute part (a), the amount will usually be from 5 to 20% by weight, in particular from 5 to 15% by weight, preferably from 7 to 12% by weight. If the composition contains R125, it will be appreciated that the concentration of R125 can be divided between components (a) and (b).

The concentration of component (b) is 30 to 94% by weight, generally 50 to 90% by weight, in particular 75 to 90% by weight.

Typically, hydrocarbons which may be used as component (c) and which may be saturated or unsaturated include methylenecyclopropane, 1-butene, cis and trans-2-butene, butane, cyclobutane, cyclopentene, cyclopentane, 2-methyl -1-butene, 2-methyl-2-butene, 3-methyl-1-butene, 1-pentene, cis and trans-2-pentene, 2-methylbutane, pentane and mixtures of two or more thereof. Particular preference is given to the use of n-butane (R600).

Specific formulations that have been shown to be effective include:

 weight% weight%

                                (a) (b)

R218 9 R125 46 46.5

R134a 88 50 50

n-butane 3 4 3.5

The following examples illustrate the invention in more detail; Examples 2, 3 and 5 are included for comparison.

Worst case fractionation studies:

The device used for this measurement consists of a small stainless steel cylinder (343 cm ³ ) which is allowed to equilibrate for at least 30 minutes by placing the blend under evaluation at various filling ratios and then placing it in a temperature control tank which is brought to an appropriate temperature. do. The temperature in the bath is kept within 0.1 ° C and monitored by a platinum resistance thermometer. Once equilibrated, a 75 cm ³ sample cylinder is attached to the test cylinder using the instantaneous connection and the empty space between the test cylinder and the sample cylinder is evacuated with a vacuum pump. Allow the system to stand for at least 15 minutes to check for leaks and then slowly introduce steam from the test cylinder into the sample cylinder using a metering valve. Once the pressure in the sample cylinder reaches 1 atmosphere, the introduction is stopped, the two cylinders are separated, and the sample cylinder is removed for GLC analysis. The GLC is calibrated using three independent analyzes of standards prepared in such a way that they are very close to the expected vapor composition for the test mixture. This sampling is repeated and the same sample is analyzed on GLC. This process was repeated at various temperatures with varying filling ratios and the worst case result was the highest hydrocarbon content.

The results obtained are shown in the table below. Flammability tests measured using the method detailed in ASTM E 681-85 show that the formulations of Examples 1 and 4 are significantly superior to the formulations of Examples 2, 3 and 5, while retaining good freezing performance. It will be noted that the vapors of the Example 1 (and 4) compositions were non-flammable. Similar comments apply to compositions R125-46.5%, R134a-50% and R600-3.5%.

Claims (26)

(i) pentafluoroethane, 1,1,1,2- or 1,1,2,2-tetrafluoroethane, 1,1-difluoroethane, trifluoromethoxypentafluoroethane, 1, 1,1,2,3,3,3-heptafluoropropane or 1,1,1,2,2,3,3-heptafluoropropane, or a mixture of two or more thereof, from 30 to 30, based on the weight of the composition An amount of 50% by weight; (ii) an amount of from 1 to 4% by weight, based on the weight of the composition, of an unsubstituted hydrocarbon of formula C _n H _m , wherein n is at least 4 and m is at least 2n-2, but not methyl propane; And as the rest, (iii) a refrigerant composition containing pentafluoroethane, trifluoromethoxydifluoromethane or hexafluorocyclopropane, or a mixture of two or more thereof, in an amount of up to 60% by weight, based on the weight of the composition. The composition of claim 1 wherein component (i) is present in an amount of 50% by weight, based on the weight of the composition. The composition of claim 1 wherein component (i) is 1,1,1,2-tetrafluoroethane or a mixture of 1,1,1,2-tetrafluoroethane and pentafluoroethane. A composition according to claim 1, wherein component (ii) is present in an amount of from 2 to 4% by weight, based on the weight of the composition. The composition of claim 4 wherein component (ii) is present in an amount of from 3 to 4 weight percent, based on the weight of the composition. The composition according to claim 1, wherein component (ii) is a mixture of said hydrocarbons. The composition according to claim 1, wherein component (ii) contains a hydrocarbon having 4 or 5 carbon atoms. 8. The composition of claim 7, wherein component (ii) is n-butane. delete delete delete delete delete A cooling device containing the composition according to any one of claims 1 to 3 as a refrigerant. A method of refrigeration comprising evaporating the composition of claim 1 in the vicinity of the object to be cooled. The cooling device of claim 14, wherein the cooling device is designed to use chlorodifluoromethane (R22) as the refrigerant. delete (i) pentafluoroethane, 1,1,1,2- or 1,1,2,2-tetrafluoroethane, 1,1-difluoroethane, trifluoromethoxypentafluoroethane, 1, 1,1,2,3,3,3-heptafluoropropane or 1,1,1,2,2,3,3-heptafluoropropane, or a mixture of two or more thereof, from 50 to 50, based on the weight of the composition The amount of 75% by weight; (ii) an amount of from 1 to 4% by weight, based on the weight of the composition, of an unsubstituted hydrocarbon of formula C _n H _m , wherein n is at least 4 and m is at least 2n-2, but not methyl propane; And as the rest, (iii) a refrigerant composition containing pentafluoroethane, trifluoromethoxydifluoromethane or hexafluorocyclopropane, or a mixture of two or more thereof. 19. The composition of claim 18, wherein component (i) is 1,1,1,2-tetrafluoroethane or a mixture of 1,1,1,2-tetrafluoroethane and pentafluoroethane. 20. The composition of claim 18 or 19, wherein component (iii) is pentafluoroethane. (i) 1,1,1,2- or 1,1,2,2-tetrafluoroethane or pentafluoroethane and 1,1,1,2- or 1,1,2,2-tetrafluoro The mixture of roethane in an amount of 30 to 94% by weight, based on the weight of the composition; (ii) an amount of from 1 to 4% by weight, based on the weight of the composition, of an unsubstituted hydrocarbon of formula C _n H _m , wherein n is at least 4 and m is at least 2n-2, but not methyl propane; And (iii) a refrigerant composition containing an amount of 5 to 60% by weight of the composition when the concentration of pentafluoroethane is not 5 to 20% by weight of the composition. The method of claim 8, (i) 46-46.5 weight percent of pentafluoroethane; (ii) 50% by weight of 1,1,1,3-tetrafluoroethane; And (iii) 3.5 to 4 weight percent of n-butane. delete delete (i) pentafluoroethane, 1,1,1,2- or 1,1,2,2-tetrafluoroethane, 1,1-difluoroethane, 1,1,1,2,3,3 , 3-heptafluoropropane or 1,1,1,2,2,3,3-heptafluoropropane, or a mixture of two or more thereof in an amount of 30 to 94% by weight, based on the weight of the composition; (ii) an unsubstituted hydrocarbon of the formula C _n H _m , wherein n is at least 4 and m is at least 2 n-2, which is not methyl propane, as a substitute for chlorofluoromethane, from 1 to 1, based on the weight of the composition An amount of 10% by weight; And (iii) a refrigerant composition containing pentafluoroethane in an amount of from 5 to 60% by weight, based on the weight of the composition. delete