EP2831193A1

EP2831193A1 - Compositions of 2,4,4,4-tetrafluorobut-1-ene and 1-methoxyheptafluoropropane

Info

Publication number: EP2831193A1
Application number: EP13715274.0A
Authority: EP
Inventors: Wissam Rached
Original assignee: Arkema France SA
Current assignee: Arkema France SA
Priority date: 2012-03-29
Filing date: 2013-03-07
Publication date: 2015-02-04
Also published as: AU2013239588A1; CN104220552A; US9732262B2; AU2013239588B2; JP6081573B2; KR20140142251A; US20170306206A1; FR2988729B1; US20150052918A1; FR2988729A1; WO2013144475A1; JP2015512991A; CN104220552B

Abstract

The invention relates to the use of a composition comprising 2,4,4,4-tetrafluorobut-1-ene and 1-methoxyheptafluoropropane as a heat transfer fluid. The invention also relates to associated units, methods and compositions.

Description

COMPOSITIONS OF 2A4.4-TETRAFLUOROBUT-1 -ENE

AND 1-METHOXYHEPTAFLUOROPROPANE

FIELD OF THE INVENTION

The present invention relates to 2,4,4,4-tetrafluorobut-1-ene and 1-methoxyheptafluoropropane compositions and their use as heat transfer fluids. TECHNICAL BACKGROUND

Fluorocarbon-based fluids are widely used in vapor compression heat transfer systems, including air conditioning, heat pump, refrigeration or freezing devices. These devices have in common to rely on a thermodynamic cycle comprising the vaporization of the fluid at low pressure (in which the fluid absorbs heat); compressing the vaporized fluid to a high pressure; condensing the vaporized fluid into a high pressure liquid (in which the fluid emits heat); and the expansion of the fluid to complete the cycle.

The choice of a heat transfer fluid (which may be a pure compound or a mixture of compounds) is dictated on the one hand by the thermodynamic properties of the fluid, and on the other hand by additional constraints. Thus, a particularly important criterion is that of the impact of the fluid considered on the environment. In particular, chlorinated compounds (chlorofluorocarbons and hydrochlorofluorocarbons) have the disadvantage of damaging the ozone layer. Thus, non-chlorinated compounds such as hydrofluorocarbons, fluoroethers and fluoroolefins are now generally preferred.

It is also still necessary to develop other heat transfer fluids having a lower global warming potential (GWP) than currently used heat transfer fluids, and having equivalent or improved performance.

US 2005/0188697 discloses the use of polyfluorinated ethers such as 1-methoxyheptafluoropropane (or HFE-7000) as a heat transfer fluid. The document WO 2010/100254 describes the use of various tetrafluorobutenes and especially 2,4,4,4-tetrafluorobut-1-ene (HFO-1354mfy), in various applications including that of heat transfer.

WO 201 1/050017 discloses the use of HFO-1354mfy as an expanding agent. The document mentions a list of other blowing agents that may possibly be used in combination with HFO-1354mfy. The HFE-7000 is in this list.

There is still a need to develop other heat transfer fluids that are less harmful to the ozone layer and have a relatively low GWP, in order to replace the usual heat transfer fluids.

SUMMARY OF THE INVENTION

The invention relates to the use of a composition comprising 2,4,4,4-tetrafluorobut-1-ene and 1-methoxyheptafluoropropane as a heat transfer fluid.

According to one embodiment, the composition comprises from 1 to 99% of 2,4,4,4-tetrafluorobut-1-ene and from 1 to 99% of 1-methoxyheptafluoropropane; and preferably:

from 50 to 98% of 2,4,4,4-tetrafluorobut-1-ene and from 2 to 50% of 1-methoxyheptafluoropropane; more preferably 75 to 97% of 2,4,4,4-tetrafluorobut-1-ene and 3 to 25% of 1-methoxyheptafluoropropane; and ideally 85 to 95% 2,4,4,4-tetrafluorobut-1-ene and 5 to 15% 1-methoxyheptafluoropropane; or

from 20 to 99% of 2,4,4,4-tetrafluorobut-1-ene and from 1 to 80% of 1-methoxyheptafluoropropane; more preferably 30 to 95% of 2,4,4,4-tetrafluorobut-1-ene and 5 to 70% of 1-methoxyheptafluoropropane; and ideally 65 to 90% 2,4,4,4-tetrafluorobut-1-ene and 10 to 35% 1-methoxyheptafluoropropane; or

from 1 to 30% of 2,4,4,4-tetrafluorobut-1-ene and from 70 to 99% of 1-methoxyheptafluoropropane and ideally from 5 to 20% of 2,4,4,4-tetrafluorobut-1; and from 80 to 95% 1-methoxyheptafluoropropane.

According to one embodiment, the composition consists of a mixture of

2,4,4,4-tetrafluorobut-1-ene and 1-methoxyheptafluoropropane. According to one embodiment, the composition is substantially azeotropic, preferably is azeotropic.

According to one embodiment, the composition is non-flammable.

The invention also relates to a heat transfer composition, comprising:

a heat transfer fluid comprising 2,4,4,4-tetrafluorobut-1-ene and 1-methoxyheptafluoropropane; and

one or more additives chosen from lubricants, stabilizers, surfactants, tracer agents, fluorescent agents, odorants, solubilizing agents and mixtures thereof.

According to one embodiment, the heat transfer fluid comprises from 1 to 99% of 2,4,4,4-tetrafluorobut-1-ene and from 1 to 99% of 1-methoxyheptafluoropropane; preferably

According to one embodiment, the heat transfer fluid consists of a mixture of 2,4,4,4-tetrafluorobut-1-ene and 1-methoxyheptafluoropropane.

According to one embodiment, the heat transfer fluid is substantially azeotropic, preferably is azeotropic; and / or the heat transfer fluid is non-flammable. The invention also relates to a heat transfer installation comprising a vapor compression circuit containing a composition as described above as a heat transfer fluid or containing a heat transfer composition as described above.

According to one embodiment, the installation is selected from mobile or stationary heat pump heating, air conditioning, and especially automotive air conditioning or stationary centralized air conditioning, refrigeration, freezing and Rankine cycles; and which is preferably an air conditioning installation.

The invention also relates to a method for heating or cooling a fluid or a body by means of a vapor compression circuit containing a heat transfer fluid, said method comprising successively the evaporation of the transfer fluid. of heat, compression of the heat transfer fluid, condensation of the heat medium and expansion of the heat transfer fluid, wherein the heat transfer fluid is a composition as mentioned above.

The invention also relates to a method for reducing the environmental impact of a heat transfer installation comprising a vapor compression circuit containing an initial heat transfer fluid, said method comprising a step of replacing the heat transfer fluid. initial heat in the vapor compression circuit by a final transfer fluid, the final transfer fluid having a GWP lower than the initial heat transfer fluid, wherein the final heat transfer fluid is a composition as mentioned above; above ; and wherein the initial heat transfer fluid is preferably 2,2-dichloro-1,1,1-trifluoroethane.

The invention also relates to a composition comprising 1 to 99% 2,4,4,4-tetrafluorobut-1-ene and 1 to 99% 1-methoxyheptafluoropropane; and preferably comprising:

from 20 to 99% of 2,4,4,4-tetrafluorobut-1-ene and from 1 to 80% of 1-methoxyheptafluoropropane; more preferably 30 to 95% of 2,4,4,4-tetrafluorobut-1-enene and 5 to 70% 1-methoxyheptafluoropropane; and ideally 65 to 90% 2,4,4,4-tetrafluorobut-1-ene and 10 to 35% 1-methoxyheptafluoropropane; or

According to one embodiment, the composition consists of a mixture of 2,4,4,4-tetrafluorobut-1-ene and 1-methoxyheptafluoropropane.

According to one embodiment, the composition is substantially azeotropic, preferably azeotropic.

According to one embodiment, the composition is non-flammable.

The present invention makes it possible to meet the needs felt in the state of the art. It more particularly provides new low-GWP compositions that are not harmful for the ozone layer and that can be used (among others) as heat transfer fluids, in particular as a replacement for conventional heat transfer fluids, and especially 2,2-dichloro-1,1,1-trifluoroethane (HCFC-123).

In particular, the invention provides in some embodiments azeotropic or quasi-azeotropic compositions.

In some embodiments, the invention provides heat transfer fluids that exhibit equivalent or improved energy performance over conventional heat transfer fluids, and particularly with respect to HCFC-123.

In certain embodiments, the compositions according to the invention exhibit in particular an equivalent or improved volumetric capacity and / or an equivalent or improved coefficient of performance compared to the compositions of the state of the art. According to some embodiments, substitution of HCFC-123 can take place without modification of the heat transfer plant and its operating parameters.

In some embodiments, the invention provides heat transfer fluids that are less flammable and / or less toxic than those of the state of the art. In particular, these heat transfer fluids may be less flammable than pure HFO-1354mfy and less toxic than pure HFE-7000. BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows the liquid-vapor equilibrium curve of the binary mixture HFO-1354mfy / HFE-7000. The molar proportion of HFO-1354mfy in the mixture is shown on the abscissa, and the pressure in bar on the ordinate. Liquid data is represented by crosses, and gas data by circles. The liquid domain of the graph is denoted L, and the vapor domain is denoted V.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The invention is now described in more detail and without limitation in the description which follows.

Unless otherwise stated, in the whole of the application the proportions of compounds indicated are given in molar percentages.

According to the present application, the global warming potential (GWP) is defined with respect to the carbon dioxide and with respect to a duration of 100 years, according to the method indicated in "The scientific assessment of ozone depletion, 2002, a report of the World Meteorological Association's Global Ozone Research and Monitoring Project.

By "heat transfer compound" or "heat transfer fluid" (or refrigerant), is meant a compound, respectively a fluid, capable of absorbing heat by evaporating at low temperature and low pressure and to reject heat by condensing at high temperature and high pressure, in a vapor compression circuit. In general, a heat transfer fluid may comprise one, two, three or more than three heat transfer compounds.

By "heat transfer composition" is meant a composition comprising a heat transfer fluid and optionally one or more additives which are not heat transfer compounds for the intended application.

The additives may especially be chosen from lubricants, nanoparticles, stabilizers, surfactants, tracer agents, fluorescent agents, odorants and solubilizing agents.

The stabilizer (s), when present, preferably represent at most 5% by weight in the heat transfer composition. Among the stabilizers, mention may in particular be made of nitromethane, ascorbic acid, terephthalic acid, azoles such as azole toluene or benzotriazole, phenol compounds such as tocopherol, hydroquinone, t-butyl hydroquinone, 2,6-di-tert-butyl-4-methylphenol, epoxides (optionally fluorinated or perfluorinated alkyl or alkenyl or aromatic) such as n-butylglycidyl ether, hexanedioldiglycidyl ether, allylglycidyl ether, butylphenylglycidyl ether, phosphites, phosphonates, thiols and lactones.

Lubricants that may be used include oils of mineral origin, silicone oils, paraffins of natural origin, naphthenes, synthetic paraffins, alkylbenzenes, poly-alpha olefins, polyalkene glycols, polyol esters, and / or polyvinyl ethers. The blend has improved miscibility with polyol ester oils and polyvinyl ethers.

As nanoparticles, it is possible to use nanoparticles of carbon, metal oxides (copper, aluminum), ΤΊΟ2, Al2O3, M0S2, etc.

As tracer agents (which can be detected) mention may be made of deuterated or non-deuterated hydrofluorocarbons, deuterated hydrocarbons, perfluorocarbons, fluoroethers, brominated compounds, iodinated compounds, alcohols, aldehydes, ketones, nitrous oxide and combinations thereof. The tracer agent is different from the one or more heat transfer compounds composing the heat transfer fluid.

As solubilizing agents, mention may be made of hydrocarbons, dimethyl ether, polyoxyalkylene ethers, amides, ketones, nitriles, chlorocarbons, esters, lactones, aryl ethers, fluoroethers and magnesium compounds. 1-trifluoroalkanes. The solubilizing agent is different from the one or more heat transfer compounds composing the heat transfer fluid.

As fluorescent agents, mention may be made of naphthalimides, perylenes, coumarins, anthracenes, phenanthracenes, xanthenes, thioxanthenes, naphthoxanhthenes, fluoresceins and derivatives and combinations thereof.

As odorants, mention may be made of alkyl acrylates, allyl acrylates, acrylic acids, acrylresters, alkyl ethers, alkyl esters, alkynes, aldehydes, thiols, thioethers, disulfides, allyl isothiocyanates and alkanoic acids. , amines, norbornenes, norbornene derivatives, cyclohexene, heterocyclic aromatic compounds, ascaridole, o-methoxy (methyl) phenol and combinations thereof. The heat transfer method according to the invention is based on the use of an installation comprising a vapor compression circuit which contains a heat transfer fluid. The heat transfer process may be a method of heating or cooling a fluid or a body.

The vapor compression circuit containing a heat transfer fluid comprises at least one evaporator, a compressor, a condenser and an expander, as well as heat transfer fluid transport lines between these elements. The evaporator and the condenser comprise a heat exchanger allowing a heat exchange between the heat transfer fluid and another fluid or body.

As a compressor, it is possible to use in particular a centrifugal compressor with one or more stages or a mini centrifugal compressor. Rotary, piston or screw compressors can also be used. The compressor may be driven by an electric motor or by a gas turbine (eg powered by vehicle exhaust, for mobile applications) or by gearing.

The facility may include a turbine to generate electricity (Rankine cycle).

The installation may also optionally include at least one coolant circuit used to transmit the heat (with or without change of state) between the heat transfer fluid circuit and the fluid or body to be heated or cooled.

The installation may also optionally include two or more vapor compression circuits containing identical or different heat transfer fluids. For example, the vapor compression circuits may be coupled together.

The vapor compression circuit operates in a conventional vapor compression cycle. The cycle comprises changing the state of the heat transfer fluid from a liquid phase (or two-phase liquid / vapor) to a vapor phase at a relatively low pressure, and then compressing the fluid in the vapor phase to a relatively high pressure. high, the change of state (condensation) of the heat transfer fluid from the vapor phase to the liquid phase at a relatively high pressure, and the reduction of the pressure to restart the cycle.

In the case of a cooling process, heat from the fluid or the body that is cooled (directly or indirectly via a fluid coolant) is absorbed by the heat transfer fluid, during the evaporation of the latter, and at a relatively low temperature relative to the environment. Cooling processes include air conditioning processes (with mobile installations, for example in vehicles, or stationary), refrigeration and freezing or cryogenics.

In the case of a heating process, heat is transferred (directly or indirectly via a heat transfer fluid) from the heat transfer fluid, during the condensation thereof, to the fluid or to the body that is heating, and this at a relatively high temperature compared to the environment. The installation for implementing the heat transfer is called in this case "heat pump".

It is possible to use any type of heat exchanger for the implementation of heat transfer fluids according to the invention, and in particular co-current heat exchangers or, preferably, heat exchangers against -current.

The heat transfer fluids used in the context of the present invention are compositions comprising 2,4,4,4-tetrafluorobut-1-ene (HFO-1354mfy) and 1-methoxyheptafluoropropane (HFE-7000).

According to one embodiment, these heat transfer fluids may comprise one or more additional heat transfer compounds.

These additional heat transfer compounds may be chosen especially from hydrocarbons, hydrofluorocarbons, ethers, hydrofluoroethers and fluoroolefins.

According to particular embodiments, the heat transfer fluids according to the invention may be ternary (consisting of three heat transfer compounds) or quaternary (consisting of four heat transfer compounds) compositions, in association with the lubricating oil for forming the heat transfer compositions according to the invention.

When additional heat transfer compounds are present, it is preferred that their total proportion in the above heat transfer fluids is less than or equal to 20%, or 15%, or 10%, or 5% , or 2%.

According to one embodiment, the heat transfer fluids consist essentially of a mixture of HFO-1354mfy and HFE-7000, or even consist of such a mixture (binary compositions). Impurities may be present in such heat transfer fluids, less than 1%, preferably less than 0.5%, preferably less than 0.1%, preferably less than 0.05%, and less than preferably less than 0.01%.

According to particular embodiments, the proportion of HFOs

1354mfy in the heat transfer fluid can be: 0.1 to 5%; or 5 to 10%; or 10 to 15%; or 15 to 20%; or from 20 to 25%; or 25 to 30%; or from 30 to 35%; or 35 to 40%; or 40 to 45%; or 45 to 50%; or 50 to 55%; or 55 to 60%; or from 60 to 65%; or from 65 to 70%; or 70 to 75%; or from 75 to 80%; or from 80 to 85%; or from 85 to 90%; or from 90 to 95%; or 95 to 99.9%.

According to particular embodiments, the proportion of HFE-7000 in the heat transfer fluid may be: 0.1 to 5%; or 5 to 10%; or 10 to 15%; or 15 to 20%; or from 20 to 25%; or 25 to 30%; or from 30 to 35%; or 35 to 40%; or 40 to 45%; or 45 to 50%; or 50 to 55%; or 55 to 60%; or from 60 to 65%; or from 65 to 70%; or 70 to 75%; or from 75 to 80%; or from 80 to 85%; or from 85 to 90%; or from 90 to 95%; or 95 to 99.9%.

Of the above heat transfer fluids, some have the advantage of being azeotropic or near-azeotropic.

The term "quasi-azeotropic" refers to those compositions for which, at a constant temperature, the liquid saturation pressure and the vapor saturation pressure are almost identical (the maximum pressure difference being 10%, or even advantageously 5%, relative to at the liquid saturation pressure).

For "azeotropic" compositions, at a constant temperature, the maximum pressure difference is close to 0%.

Such heat transfer fluids have the advantage of ease of implementation. In the absence of significant temperature slippage, there is no significant change in the circulating composition, and no significant change in composition in case of leakage.

Figure 1 shows the liquid-vapor equilibrium curve of the mixture of HFO-1354mfy and HFE-7000. It is found that at 75 ° C and about 4.6 bar the mixture has an azeotrope for about 90% HFO-1354mfy and 10% HFE-7000, and is nearly azeotropic for all other binary compositions. Advantageously, the compositions according to the invention are non-flammable, within the meaning of the ASHRAE 34-2007 standard, and preferably with a test temperature of 60 ° C. instead of 100 ° C.

In addition, certain compositions according to the invention have improved performances with respect to certain known heat transfer fluids, in particular for moderate temperature cooling processes, that is to say those in which the temperature of the fluid or the cooled body is -15 ° C to 15 ° C, preferably -10 ° C to 10 ° C, more preferably -5 ° C to 5 ° C (most preferably about 0 ° C).

Furthermore, certain compositions according to the invention have improved performances compared with certain known heat transfer fluids, in particular for the processes of heating at moderate temperature, that is to say those in which the temperature of the fluid or the heated body is from 30 ° C to 80 ° C, and preferably from 35 ° C to 55 ° C, more preferably from 40 ° C to 50 ° C (most preferably about 45 ° C).

In the processes of "cooling or heating at moderate temperature" mentioned above, the inlet temperature of the heat transfer fluid to the evaporator is preferably from -20 ° C. to 10 ° C., especially from -15 ° C. ° C at 5 ° C, more preferably at -10 ° C to 0 ° C and for example about -5 ° C; and the temperature of the onset of condensation of the heat transfer fluid at the condenser is preferably 25 ° C to 90 ° C, especially 30 ° C to 70 ° C, more preferably 35 ° C to 55 ° C C and for example about 50 ° C. These processes may be refrigeration, air conditioning or heating processes.

Certain compositions are also suitable for high temperature heating processes, that is to say those in which the temperature of the fluid or the heated body is greater than 90 ° C, for example greater than or equal to 1 10 ° C or greater than or equal to 130 ° C, and preferably less than or equal to 170 ° C.

Certain compositions are also suitable for electricity generation processes (Rankine cycle), which are processes in which the temperature of the hot source (fluid or heated body) is greater than 90 ° C, for example greater than or equal to 1 10 ° C or greater than or equal to 130 ° C, and preferably less than or equal to 170 ° C.

Certain compositions according to the invention have improved performances with respect to certain known heat transfer fluids, in particular for low temperature refrigeration processes, that is to say those in which the temperature of the cooled fluid or body is from -40 ° C to -10 ° C, and preferably from -35 ° C to -25 ° C, more preferably from -30 ° C to -20 ° C ° C (ideally about -25 ° C).

In the "low temperature refrigeration" processes mentioned above, the inlet temperature of the heat transfer fluid to the evaporator is preferably from -45 ° C. to -15 ° C., especially from -40 ° C. at -20 ° C, more preferably -35 ° C to -25 ° C and for example about -30 ° C; and the temperature of the onset of condensation of the heat transfer fluid at the condenser is preferably 25 ° C to 80 ° C, especially 30 ° C to 60 ° C, more preferably 35 ° C to 55 ° C C and for example about 40 ° C.

The compositions according to the invention can be used to replace various heat transfer fluids in various heat transfer applications, for example in air conditioning. For example, the compositions according to the invention can serve to replace:

1,1,1,2-tetrafluoroethane (R134a);

1,1-Difluoroethane (R152a);

1,1,1,3,3-pentafluoropropane (R245fa);

mixtures of pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a) and isobutane (R600a), namely R422;

chlorodifluoromethane (R22);

the mixture of 51.2% chloropentafluoroethane (R 15) and 48.8% chlorodifluoromethane (R 22), namely R 502;

- any hydrocarbon;

the mixture of 20% of difluoromethane (R32), 40% of pentafluoroethane (R125) and 40% of 1, 1, 1, 2-tetrafluoroethane (R134a), namely R407A;

the mixture of 23% of difluoromethane (R32), 25% of pentafluoroethane (R125) and 52% of 1, 1, 1, 2-tetrafluoroethane (R134a), namely R407C;

the mixture of 30% of difluoromethane (R32), 30% of pentafluoroethane (R125) and 40% of 1,1,1,2-tetrafluoroethane (R134a), namely R407F;

R1234yf (2,3,3,3-tetrafluoropropene);

R1234ze (1, 3,3,3-tetrafluoropropene).

In addition, the following preferred compositions are particularly suitable for the replacement of HCFC-123: from 20 to 99% of HFO-1354mfy and from 1 to 80% of HFE-7000;

preferably from 30 to 95% of HFO-1354mfy and from 5 to 70% of HFE-7000;

more particularly 65 to 90% HFO-1354mfy and 10 to 35% HFE-7000.

Indeed, in this case the average molar mass as the boiling temperature of the heat transfer fluid are very close to the molar mass and the boiling temperature of HCFC-123. Thus, the composition comprising 65% of HFO-1354mfy and about 35% of HFE-7000 has an average molar mass of 153 g / mol (as against 152.93 g / mol for HCFC-123) and a boiling temperature equivalent to temperature of HCFC-123.

Thus, the above preferred compositions allow substitution of HCFC-123 without modification or substantially without modification of the heat transfer plant or its operating parameters.

Correlatively, these preferred compositions are particularly suitable for all applications in which HCFC-123 is generally used. Thus, these preferred compositions are particularly suitable for use as heat transfer fluids in heat transfer plants having centrifugal compressors, including direct drive centrifugal compressors. These compressors are more efficient and less expensive than compressors with gearbox.

Centrifugal compressors can be driven by an electric motor, a steam turbine, a gas turbine, a heat engine or the like.

Preferably, the speed of sound obtained is close to that obtained with HCFC-123 and / or the volumetric capacity obtained is close to that obtained with HCFC-123 and / or the operating pressure at the condenser obtained is close to that obtained with HCFC-123.

Thus, the above preferred compositions can maintain a constant compressor rotational speed when HCFC-123 is substituted.

Other particularly preferred compositions are the compositions comprising from 1 to 30% of 2,4,4,4-tetrafluorobut-1-ene and from 70 to

99% of 1-methoxyheptafluoropropane and ideally 5 to 20% of 2,4,4,4-tetrafluorobut-1-ene and 80 to 95% of 1 - méthoxyheptafluoropropane. Indeed, these compositions have particularly satisfactory non-flammability properties.

EXAMPLE: determination of the liquid / vapor equilibrium curve

The curve of FIG. 1 is obtained as follows.

An apparatus based on the analytical static technique is used to study the binary mixtures of HFO-1354mfy and HFE-7000.

More precisely, an equilibrium cell comprising a sapphire tube equipped with two electromagnetic ROLSITM samplers is used. It is immersed in a cryothermostat bath (HUBER HS40). Variable speed rotary field driving magnetic stirring is used to accelerate equilibrium attainment.

The analysis of the samples is carried out by chromatography (HP5890 seriesll) in the gas phase using a katharometer (TCD). We start the loading of the cell with the product at the lowest vapor pressure (heavy product - highest boiling point, here the HFE-7000). Loading is carried out from below, in order to avoid drops of liquid on the vapor sampling capillary (upper cell). The heavy product is gradually loaded to obtain a sufficient level of liquid in the cell.

After each sample, we add a mass of light product (here

HFO-1354mfy) to vary the concentration and to be able to draw the equilibrium curves. Stabilization of the system (temperature and pressure) is expected after each loading of the light product.

The liquid sample is taken from the capillary at the bottom of the cell, and the gas sample is taken from the top of the cell using the ROLSITM (sampler). The ROLSI opening time is chosen by the operator. ROLSITMs send samples directly into GC analysis.

The quantities of samples taken at each sampling are small enough not to disturb significantly, the balance in the cell (about 1 mg, while the cell contains about 15 to 40 g of product). Prior to purging, it is necessary to avoid erroneous values.

The temperature and pressure values are always recorded before the sampling is started; we consider that the conditions are identical for each point.

After each loading, a small degassing of the vapor phase is necessary before taking the samples. Thanks to the preliminary calibration of CPG in pure product, we find the number of moles of each product and we deduce the mol% for all the liquid and vapor samples.

Claims

1. Use of a composition comprising 2,4,4,4-tetrafluorobut-1-ene and 1-methoxyheptafluoropropane as a heat transfer fluid.

The use of claim 1, wherein the composition comprises 1-99% 2,4,4,4-tetrafluorobut-1-ene and 1-99% 1-methoxyheptafluoropropane; and preferably:

from 50 to 98% of 2,4,4,4-tetrafluorobut-1-ene and from 2 to 50% of 1-methoxyheptafluoropropane; more preferably 75 to 97% 2,4,4,4-tetrafluorobut-1-ene and 3 to 25% 1-methoxyheptafluoropropane; and ideally 85 to 95% 2,4,4,4-tetrafluorobut-1-ene and 5 to 15% 1-methoxyheptafluoropropane; or

from 20 to 99% of 2,4,4,4-tetrafluorobut-1-ene and from 1 to 80% of 1-methoxyheptafluoropropane; more preferably 30 to 95% 2,4,4,4-tetrafluorobut-1-ene and 5 to 70% 1-methoxyheptafluoropropane; and ideally 65 to 90% 2,4,4,4-tetrafluorobut-1-ene and 10 to 35% 1-methoxyheptafluoropropane; or

Use according to claim 1 or 2, wherein the composition is a mixture of 2,4,4,4-tetrafluorobut-1-ene and 1-methoxyheptafluoropropane.

4. Use according to one of claims 1 to 3, wherein the composition is substantially azeotropic, preferably is azeotropic.

Use according to one of claims 1 to 4, wherein the composition is non-flammable.

A heat transfer composition, comprising:

A heat transfer composition according to claim 6, wherein the heat transfer fluid comprises 1 to 99% 2,4,4,4-tetrafluorobut-1-ene and 1 to 99% 1-methoxyheptafluoropropane; preferably

A heat transfer composition according to claim 6 or 7, wherein the heat transfer fluid consists of a mixture of 2,4,4,4-tetrafluorobut-1-ene and 1-methoxyheptafluoropropane.

9. heat transfer composition according to one of claims 6 to 8, wherein the heat transfer fluid is substantially azeotropic, preferably is azeotropic; and / or wherein the heat transfer fluid is non-flammable.

A heat transfer apparatus comprising a vapor compression circuit containing a composition as recited in one of claims 1 to 5 as a heat transfer fluid or containing a heat transfer composition according to any one of Claims 6 to 9.

11. Installation according to claim 10, which is selected from mobile or stationary heat pump heating, air conditioning, including automotive air conditioning or stationary centralized air conditioning, refrigeration, freezing and Rankine cycles; and which is preferably an air conditioning installation.

A method of heating or cooling a fluid or a body by means of a vapor compression circuit containing a heat transfer fluid, said method comprising successively evaporation of the heat transfer fluid, the compression of the heat transfer fluid, condensation of the heat medium and expansion of the heat transfer fluid, wherein the heat transfer fluid is a composition as mentioned in one of claims 1 to 5.

A method of reducing the environmental impact of a heat transfer facility comprising a vapor compression circuit containing an initial heat transfer fluid, said method comprising a step of replacing the initial heat transfer fluid in the vapor compression circuit by a final transfer fluid, the final transfer fluid having a GWP lower than the heat transfer fluid initial, in which the final heat transfer fluid is a composition as mentioned in one of claims 1 to 5; and wherein the initial heat transfer fluid is preferably 2,2-dichloro-1,1,1-trifluoroethane.

A composition comprising 1-99% 2,4,4,4-tetrafluorobut-1-ene and 1-99% 1-methoxyheptafluoropropane; and preferably comprising:

The composition of claim 14 consisting of a mixture of 2,4,4,4-tetrafluorobut-1-ene and 1-methoxyheptafluoropropane.

The composition of claim 14 or 15 which is substantially azeotropic, preferably azeotropic.

Composition according to one of claims 14 to 16, which is non-flammable.