DESC:FORM 2
THE PATENT ACT 1970
(39 of 1970)
&
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)

“COMPOSITIONS COMPRISING HYDROFLUOROALKANES”

SRF LIMITED, AN INDIAN COMPANY,
SECTOR 45, BLOCK-C, UNICREST BUILDING,
GURGAON – 122003,
HARYANA (INDIA)

The following specification particular describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention relates to compositions for use in refrigeration, air-conditioning, and heat pump systems wherein the composition comprises at least one hydrofluoroalkane.

BACKGROUND OF THE INVENTION
The refrigeration industry has been working for the past few decades to find replacement refrigerants for the ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) being phased out as a result of the Montreal Protocol. With global warming becoming an increasingly serious issue worldwide, the development of environmentally friendly refrigeration and air-conditioning systems has become increasingly important.
Refrigerants have a great influence not only on global warming, but also on the performance of refrigeration and air-conditioning systems. Therefore, the selection of a refrigerant has an important role in reducing carbon dioxide emissions that contribute to global warming.
Recently, various partially fluorinated hydrocarbons (HFC’s), with a lower global warming potential (GWP) than known chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), have been proposed.
Various methods are known in the art which provides the compositions comprising R134a and R32.
U.S. Pat. No. 5,589,098 provides a mixture consisting essentially of a substantially constant boiling, near-azeotropic composition consisting of 1-6 weight percent difluoromethane and 94-9 weight percent 1,1,2,2-tetrafluoroethane and additionally R134a, wherein when the temperature is adjusted to about 25°C, the composition boils at a vapor pressure of about 78-91 psia, and wherein when 50 weight percent of the composition is evaporated, the vapor pressure of the composition changes by 10 percent or less.
E.P. Pat. No. 0610424 provides a refrigerant composition comprising difluoromethane and 1,1,1,2-tetrafluoroethane in the relative weight ratio of from 5:90 to 90:5, characterized in that the composition further includes from 5 to 90 weight percent 1,1,2,2-tetrafluoroethane to increase the coefficient of performance of the composition.
E.P. Pub. No. 0505436 provides an azeotrope-like compositions comprising 5 to 90% by weight of 1,1,1,2-tetrafluoroethane and 10 to 95% by weight of 1,1-difluoroethane which have a vapor pressure of about 76 psia ± 5 psia at 20°C.
It is generally considered important, however, at least with respect to heat transfer fluids, that any potential substitute must also possess those properties present in many of the most widely used fluids, such as excellent heat transfer properties, chemical stability, low or no-toxicity, non-flammability and/or lubricant compatibility, among others.
Applicants have thus come to appreciate a need for compositions, and particularly heat transfer compositions, that are highly advantageous in heating and cooling systems and methods, particularly vapor compression heating and cooling systems, and even more particularly low temperature refrigerant systems.

OBJECT OF THE INVENTION
The main object of the present invention is to provide a composition for use in refrigeration, air-conditioning and heat pump systems comprising at least one hydrofluoroalkane.
SUMMARY OF THE INVENTION
The present invention provides a composition comprising 1% by weight to 99% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 99% by weight to 1% by weight of difluoromethane (R32).

DETAILED DESCRIPTION OF THE INVENTION
As used herein, the non-azeotropic composition is a mixture of two or more substances that behaves as a simple mixture rather than a single substance. One way to characterize a non-azeotropic composition is that the vapor produced by partial evaporation or distillation of the liquid has a substantially different composition as the liquid from which it was evaporated or distilled, that is, the admixture distills/refluxes with substantial composition change.
Flammability is a term used to mean the ability of a composition to ignite and/or propagate a flame. Determination of whether a refrigerant compound or mixture is flammable, or non-flammable can be done by testing under the conditions of ASTM-681. The compositions of the present invention are mostly non-flammable.
Global warming potential (GWP) is an index for estimating relative global warming contribution due to atmospheric emission of a kilogram of a particular greenhouse gas compared to emission of a kilogram of carbon dioxide. GWP can be calculated for different time horizons showing the effect of atmospheric lifetime for a given gas. The GWP for the 100-year time horizon is commonly the value referenced. For mixtures, a weighted average can be calculated based on the individual GWPs for each component. The standard GWP values for R22, R32, R125 and tetrafluoroethane has been taken from IIPCC 5th Assessment report 2014 (AR5). The GWP of the refrigerant mixture has been derived from mass fraction and the corresponding GWP values.
Ozone depletion potential (ODP) is a number that refers to the amount of ozone depletion caused by a substance. The ODP is the ratio of the impact on ozone of a chemical compared to the impact of a similar mass of CFC-11 (fluorotrichloromethane).
As used herein, a refrigerant is defined as a heat transfer fluid that undergoes a phase change from liquid to gas and back again during a cycle used to transfer of heat.
The recirculation is carried out using a pump to ensure homogeneity of the composition.
The term “about” as used in the present invention refers to 10% deviation from the specified value in both sides.
In an aspect, the present invention provides a composition comprising 1% by weight to 99% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 99% by weight to 1% by weight of difluoromethane (R32).
In an embodiment, the present invention provides a composition comprising 96% by weight to 99% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 4% by weight to 1% by weight of difluoromethane (R32).
In another embodiment, the present invention provides a composition comprising 96.5% by weight to 97.5% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 3.5% by weight to 2.5% by weight of difluoromethane (R32).
In another embodiment, the present invention provides a composition comprising 97.5% by weight to 98.5% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 2.5% by weight to 1.5% by weight of difluoromethane (R32).
In another embodiment, the present invention provides a composition comprising 98.5% by weight to 99% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 1.5% by weight to 1% by weight of difluoromethane (R32).
In another aspect, the present invention provides a composition comprising 10% by weight to 95% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 90% by weight to 5% by weight of difluoromethane (R32).
In an embodiment, the present invention provides a composition comprising 20% by weight to 80% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 80% by weight to 20% by weight of difluoromethane (R32).
In another embodiment, the present invention provides a composition comprising 20% by weight to 50% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 80% by weight to 50% by weight of difluoromethane (R32).
In another embodiment, the present invention provides a composition comprising 20% by weight to 28% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 80% by weight to 72% by weight of difluoromethane (R32).
In another embodiment, the present invention provides a composition comprising 30% by weight to 40% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 70% by weight to 60% by weight of difluoromethane (R32).
In another aspect, the present invention provides a composition comprising 1% by weight to 19% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 99% by weight to 81% by weight of difluoromethane (R32).
In an embodiment, the present invention provides a composition comprising 2% by weight to 15% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 98% by weight to 85% by weight of difluoromethane (R32).
In another embodiment, the present invention provides a composition comprising 2% by weight to 5% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 98% by weight to 95% by weight of difluoromethane (R32).
In another aspect, the present invention provides a composition comprising 10% by weight to 15% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 90% by weight to 85% by weight of difluoromethane (R32).
In another embodiment, the present invention provides a refrigerant composition comprising R134a and R32 which is prepared by mixing these components to get a mixture, wherein the mixing is assisted with recirculation or agitators.
The composition according to the present invention may additionally comprise one or more refrigerant oils. The refrigerant oil is not limited and can be suitably selected from typically used refrigerant oils. When doing so, a refrigerant oil that is superior, for example, in miscibility with the mixture and action of improving the stability of the mixture can be suitably selected, as necessary.
The base oil of the refrigerant oil is preferably, for example, at least one member selected from the group consisting of polyalkylene glycols (PAG), polyol esters (POE), and polyvinyl ethers (PVE).
The refrigerant oil may further contain an additive in addition to the base oil. The additive may be at least one member selected from the group consisting of lubricants, dyes (including Ultra Violet dyes), solubilizing agents, compatibilizers, stabilizers, tracers, perfluoropolyethers, anti-wear agents, extreme pressure agents, corrosion and oxidation inhibitors, metal surface energy reducers, metal surface deactivators, free radical scavengers, foam control agents, viscosity index improvers, pour point depressants, detergents, viscosity adjusters, and mixtures thereof. Indeed, many of these optional other components fit into one or more of these categories and may have qualities that lend themselves to achieve one or more performance characteristic.
In another embodiment of this aspect of the present invention, the refrigerant compositions are non-azeotropic mixture.
In another embodiment of this aspect of the present invention, the refrigerant composition is preferably charged in liquid form.
Additionally, the composition of the present invention comprises a flame retardant, selected from phosphorus-based materials and non-phosphorus-based materials, to reduce the flammability of compositions.
The non-phosphorus-based materials comprises inert filler materials, such as calcium carbonate. aluminum trihydrate, magnesium hydroxide and calcium carbonate. Similarly the phosphorus-based flame-retardants comprises salt of melamine and bis(pentaerythritol phosphate) phosphoric acid and ammonium polyphosphate.
In another embodiment of this aspect, the present invention provides a refrigeration process using the refrigerant composition comprising the steps of:
a) condensing the refrigerant composition; and
b) evaporating the refrigerant composition.
The quantity of various components as used in the present invention are described in the table below.
Table 1
Composition R134a R32 Boiling
point Molar
Mass GWP
1 99 1 1293.77 101.06 1293.77
2 98 2 1287.54 100.11 1287.54
3 97 3 1281.31 99.172 1281.31

Table 1a
Composition R134a R32 Boiling Point Molar Mass GWP
4 40 60 -47 64.71 977
5 35 65 -48 62.79 939
6 31 69 -49 61.34 909
7 28 72 -49.5 60.29 886
8 25 75 -49.5 59.28 863
9 22 78 -50 58.31 841
10 15 85 -50.5 56.15 788
11 10 90 -51 54.7 750
12 5 95 -51 53.33 712
13 2 98 -51.5 52.53 690

The various physical and environment properties of the compositions of the present invention and prior art composition i.e., R134a at different temperature are tabulated below.
Table 2
Composition Temp (°C) Vapour Pressure (bar_g) Liquid Phase Density (kg/m?) Vapor Phase Density (kg/m?) Liquid Phase Enthalpy (kJ/kg) Vapor Phase Enthalpy (kJ/kg) Liquid Phase Cp (kJ/kg-K)
1 0 1.9542 1291.7 14.49 200 399.78 1.345
25 5.7274 1203.5 32.483 234.65 413.43 1.4294
35 7.9716 1164.2 43.596 249.17 418.24 1.4763
45 10.736 1121.6 57.904 264.16 422.51 1.5362
50 12.336 1098.8 66.563 271.87 424.39 1.5731
2 0 1.9939 1288.7 14.552 200 400.96 1.3491
25 5.8147 1200.3 32.617 234.76 414.52 1.4343
35 8.0871 1160.9 43.778 249.32 419.28 1.4817
45 10.886 1118.2 58.153 264.37 423.5 1.5425
50 12.507 1095.3 66.856 272.11 425.35 1.5802
3 0 2.0338 1285.6 14.614 200 402.14 1.3531
25 5.9024 1197.1 32.751 234.87 415.61 1.4391
35 8.2031 1157.6 43.96 249.48 420.33 1.4872
45 11.037 1114.8 58.403 264.58 424.49 1.5489
50 12.678 1091.9 67.15 272.36 426.3 1.5872

Table 3
Composition Temperature (°C) Vapor Phase Cp (kJ/kg-K) Liquid Phase Thermal Conductivity (mW/m-K) Vapor Phase Thermal Conductivity (mW/m-K) Liquid Phase Viscosity (cP) Vapor Phase Viscosity (cP)
1 0 0.89945 92.401 11.538 0.2641 0.01088
25 1.035 81.467 13.852 0.19321 0.01185
35 1.1069 77.166 14.908 0.17055 0.01223
45 1.1968 72.87 16.11 0.15011 0.01263
50 1.2519 70.714 16.79 0.14057 0.01292
2 0 0.90169 92.793 11.561 0.26174 0.01088
25 1.0385 81.804 13.881 0.19158 0.01184
35 1.1111 77.483 14.944 0.16912 0.01222
45 1.2021 73.169 16.157 0.14886 0.01263
50 1.2578 71.004 16.846 0.1394 0.01292
3 0 0.90394 93.19 11.583 0.25942 0.01087
25 1.0419 82.144 13.909 0.18997 0.01184
35 1.1153 77.804 14.979 0.16772 0.01222
45 1.2073 73.471 16.204 0.14764 0.01263
50 1.2638 71.298 16.901 0.13825 0.01293

The compositions of the present invention have various properties which are better than the R134a compositions as mentioned below.
The compositions of the present invention have higher liquid phase enthalpy, vapour phase enthalpy, liquid phase Cp (heat capacity at constant pressure), vapour phase Cp (heat capacity at constant pressure), liquid phase thermal conductivity and vapour phase thermal conductivity than the R134a composition.
The higher the enthalpy and thermal conductivity, the higher will be heat transfer capacity and thus better will be the cooling capacity.
The higher heat capacity means that the gas composition will take more heat from evaporator leading to higher refrigerating effect per kg.
The higher the cooling capacity, the lower will be energy loss across compression and thus higher will be COP value.
Coefficient of performance (COP) is the amount of heat removed divided by the required energy input to operate the cycle. The higher the COP, the higher is the energy efficiency. COP is directly related to the energy efficiency ratio (EER) that is the efficiency rating for refrigeration or air conditioning equipment at a specific set of internal and external temperatures.
R32 and R134a used to prepare compositions of present invention are commercially available or may be prepared by methods known in the art.
It is against this and other backgrounds, which shall be filed in a detailed manner in complete specifications, in due course, the present invention is brought out and explained in following non-limiting examples.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention and specific examples provided herein without departing from the spirit and scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention that come within the scope of any claims and their equivalents.

EXAMPLE
The refrigerant compositions according to the invention having R134a and R32 were prepared at 20 to 30ºC and at atmospheric pressure and tested as per standard for automotive ACs, creating different car speed from 0kmph to 80kmph.

WE CLAIM:
1. A composition comprising 1% by weight to 99% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 99% by weight to 1% by weight of difluoromethane (R32).
2. The composition as claimed in claim 1, wherein the composition comprising 96% by weight to 99% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 4% by weight to 1% by weight of difluoromethane (R32).
3. The composition as claimed in claim 1, wherein the composition comprising 1% by weight to 19% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 99% by weight to 81% by weight of difluoromethane (R32).
4. The composition as claimed in claim 1, wherein the composition comprising 20% by weight to 50% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 80% by weight to 50% by weight of difluoromethane (R32).
5. The composition as claimed in claim 1, wherein the composition comprising 20% by weight to 28% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 80% by weight to 72% by weight of difluoromethane (R32).
6. The composition as claimed in claim 1, wherein the composition comprising 30% by weight to 40% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 70% by weight to 60% by weight of difluoromethane (R32).
7. The composition as claimed in claim 1, wherein the composition comprising 2% by weight to 15% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 98% by weight to 85% by weight of difluoromethane (R32).

Dated this 22nd day of November 2022.

ABSTRACT
“COMPOSITIONS COMPRISING HYDROFLUOROALKANES”
The present invention relates to compositions for use in refrigeration, air-conditioning, and heat pump systems wherein the composition comprising hydrofluoroalkane such as 1,1,1,2-tetrafluoroethane, difluoromethane or the like.

,CLAIMS:WE CLAIM:
1. A composition comprising 1% by weight to 99% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 99% by weight to 1% by weight of difluoromethane (R32).
2. The composition as claimed in claim 1, wherein the composition comprising 96% by weight to 99% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 4% by weight to 1% by weight of difluoromethane (R32).
3. The composition as claimed in claim 1, wherein the composition comprising 1% by weight to 19% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 99% by weight to 81% by weight of difluoromethane (R32).
4. The composition as claimed in claim 1, wherein the composition comprising 20% by weight to 50% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 80% by weight to 50% by weight of difluoromethane (R32).
5. The composition as claimed in claim 1, wherein the composition comprising 20% by weight to 28% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 80% by weight to 72% by weight of difluoromethane (R32).
6. The composition as claimed in claim 1, wherein the composition comprising 30% by weight to 40% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 70% by weight to 60% by weight of difluoromethane (R32).
7. The composition as claimed in claim 1, wherein the composition comprising 2% by weight to 15% by weight of 1,1,1,2-tetrafluoroethane (R134a) and 98% by weight to 85% by weight of difluoromethane (R32).