FR3056210A1 - PROCESS FOR SEPARATING 2-CHLORO-1,1,1,2-TETRAFLUOROPROPANE AND 2-CHLORO-3,3,3-TRIFLUOROPROPENE. - Google Patents

Abstract

The present invention relates to a process for separating 2-chloro-1,1,1,2-tetrafluoropropane and 2-chloro-3,3,3-trifluoropropene comprising the step of contacting a mixture comprising 2 chloro-3,3,3-trifluoropropene and 2-chloro-1,1,1,2-tetrafluoropropane with hydrogen in the presence of a catalyst to form a reaction mixture comprising 2-chloro-1, 1,1,2-tetrafluoropropane and 2-chloro-1,1,1-trifluoropropane.

Description

Technical area

The present invention relates to a process for the separation of a haloalkane from a halogenated olefin. In particular, the present invention relates to the separation of 2chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and 2-chloro-3,3,3-trifluoropropene (HCFO1233xf).

Context of the invention

Halogenated hydrocarbons, in particular fluorinated hydrocarbons such as hydrofluoroolefins, are compounds which have a useful structure such as various functional materials, solvents, refrigerants, blowing agents, and monomers for functional polymers or starting materials for such monomers . Hydrofluoroolefins such as 2,3,3,3-tetrafluoropropene (HFO-1234yf) have attracted attention because they show promising behavior as refrigerants with low global warming potential. 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) is an intermediate in the production of 2,3,3,3-tetrafluoropropene (HFO-1234yf) which is known in the art as described in U.S. Patent No. 8,084,653.

U.S. Patent No. 8,058,486 further describes a process for making 2,3,3,3tetrafluoropropene (HFO-1234yf) from chlorinated hydrocarbons. The process has three stages. The first step involves the fluorination of tetrachloropropene or pentachloropropane with HF to produce 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf). The second step involves the fluorination of 2-chloro-3,3,3-trifluoropropene (HCFO1233xf) with HF to produce 2-chloro-1,1,1,2,2-tetrafluoropropane (HCFC-244bb). The third and last step involves the dehydrochlorination of 2-chloro-1,1,1,2tetrafluoropropane (HCFC-244bb) to produce the product 2,3,3,3-tetrafluoropropene (HFO1234yf). In each of the stages, the conversion of intermediary is not total, not allowing recycling, favoring the formation of superfluorinated by-products such as

1,1,1,2,2-pentafluoropropane (HFC-245cb) and leading to larger reactors (lower capacity) and increased consumption of HF.

It would be preferable to remove 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and other halogenated olefin impurities produced in the first two process steps from the intermediate 2-chloro-1, 1,1,2-tetrafluoropropane (HCFC-244bb) produced before sending the charge into the dehydrochlorination reactor to produce the final product 2,3,3,3-tetrafluoropropene (HFO-1234yf). This would allow the recycling of unreacted 2-chloro-1,1,1,2tetrafluoropropane (HCFC-244bb) back to the third stage reactor, so as to minimize the yield loss.

2-chloro-1,1,2,2-tetrafluoropropane (HCFC-244bb) and 2-chloro-3,3,3trifluoropropene (HCFO-1233xf) are inseparable using the conventional separation techniques known in the art being since 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) form a binary azeotrope or an azeotrope-like composition which is described in US Patent No. 7,803,283.

U.S. Patent Nos. 8,796,493 and 9,018,430 describe methods of separating halocarbons. In particular, the inventions relate to a process for the separation of halogenated olefinic impurities such as 2-chloro-3,3,3-trifluoropropene (HCFO1233xf) from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC -244bb) using a solid adsorbent, in particular activated carbon. However, this process requires a large amount of solid specific activated carbon adsorbent since the weight ratio of organic matter adsorbed is low.

US Pat. Nos. 8,252,965 and 8,487,793 describe a process for the separation of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) from 2-chloro-3,3,3-trifluoropropene (HCFO- 1233xf) based on differences in melting points of these compounds. However, this process requires cooling, decantation, filtration and other operations at low temperature, leading to high energy consumption and industrialization difficulties.

US Pat. Nos. 8,034,251 and 8,845,921 describe azeotropic compositions of 2chloro-3,3,3-trifluoropropene (HCFC-1233xf), of 2-chloro-1,1,1,1-tetrafluoropropane (HCFC244bb), and hydrogen fluoride (HF) and a process for the separation of 2-chloro-1,1,1,2tetrafluoropropane (HCFC-244bb) from 2-chloro-3,3,3-trifluoropropene (HCFC-1233xf) by adding a third component such as HF and then separation by conventional distillation. However, this process requires the introduction of a large excess of hydrogen fluoride and then the separation of the resulting 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) still containing large amounts of HF.

There is a need for a new efficient industrial process for the separation of 2chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and 2-chloro-3,3,3-trifluoropropene (HCFO1233xf).

Summary of the invention

The present invention relates to a process for the separation of 2-chloro-1,1,1,2tetrafluoropropane and 2-chloro-3,3,3-trifluoropropene comprising the step of contacting a mixture comprising 2-chloro -3,3,3-trifluoropropene and 2-chloro-1,1,1,2tetrafluoropropane with hydrogen in the presence of a catalyst to form a reaction mixture comprising 2-chloro-1,1,1, 2-tetrafluoropropane and 2-chloro-1,1,1-trifluoropropane.

In a preferred embodiment, the process further comprises the step of distilling the reaction mixture comprising 2-chloro-1,1,1,2-tetrafluoropropane and 2-chloro-1,1,1-trifluoropropane obtained to form a stream comprising 2-chloro-1,1,1,2tetrafluoropropane and a stream comprising 2-chloro-1,1,1-trifluoropropane.

In a preferred embodiment, the catalyst is based on a metal chosen from the group consisting of metals from columns 8 to 10 of the periodic table of the elements and rhenium.

In a preferred embodiment, the catalyst is based on a metal chosen from the group consisting of nickel, palladium, rhodium, ruthenium, rhenium or platinum.

In a preferred embodiment, 3,3,3-trifluoropropene is also produced as a by-product in the reaction mixture.

In a preferred embodiment, the step of bringing the mixture of 2chloro-3,3,3-trifluoropropene and 2-chloro-1,1,1,2-tetrafluoropropane into contact with hydrogen is carried out at temperature from 20 to 200 ° C.

In a preferred embodiment, the method comprises the steps of:

(i) reaction of a mixture comprising 2-chloro-3,3,3-trifluoropropene and 2-chloro-1,1,1,2-tetrafluoropropane, and optionally 1,1,1,2,2pentafluoropropane, in the gas phase with hydrogen in the presence of a catalyst, (ii) recovery of a first stream comprising 2-chloro-1,1,1trifluoropropane, 2-chloro-1,1,1,1,2-tetrafluoropropane , optionally from

1,1,1,2,2-pentafluoropropane, unreacted hydrogen, and optionally unreacted 2-chloro-3,3,3-trifluoropropene, (iii) recycling a first part of said first flow towards step (i), (iv) recovery of a mixture comprising 2-chloro-l, l, l-trifluoropropane and 2-chloro-l, l, l, 2-tetrafluoropropane from of the remaining part of the first stream, optionally after a washing step.

In a preferred embodiment, the first stream further comprises 3,3,3trifluoropropene.

In a preferred embodiment, the remaining part of the first stream further comprises 3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane; and 2chloro-1,1,1,2-tetrafluoropropane is recovered from said remaining part of the first stream by purification, preferably by distillation.

In a preferred embodiment, said catalyst is supported on at least one of carbon, alumina, titanium oxide, silica, zirconia or fluorides thereof, calcium fluoride, calcium carbonate, barium sulfate or zeolites.

Detailed description of the present invention

In a first aspect of the present invention, a method of separating a mixture comprising 2-chloro-1,1,1,2-tetrafluoropropane and 2-chloro-3,3,3trifluoropropene is described. Said method comprises the step of bringing the mixture comprising 2-chloro-1,1,1,2-tetrafluoropropane and 2-chloro-3,3,3-trifluoropropene into contact with hydrogen in the presence of a catalyst.

In a preferred embodiment, the mixture to be contacted with hydrogen in step (i) comprises 2-chloro-3,3,3-trifluoropropene, 1,1,1,2,2pentafluoropropane and 2-chloro-1,1,1,2-tetrafluoropropane.

Preferably, the process is carried out continuously. The process is preferably carried out in the gas phase. Therefore, the present process can use a continuous hydrogenation reaction in the gas phase. The process according to the present invention leads to the formation of a mixture comprising 2-chloro-1,1,1,2-tetrafluoropropane and 2-chloro-1,1,1-trifluoropropane with a high yield and excellent selectivity . When 1,1,1,2,2-pentafluoropropane is present in the mixture to be brought into contact with hydrogen in the presence of the catalyst, the process according to the present invention leads to the formation of a mixture comprising 2 -chloro-l, l, l, 2-tetrafluoropropane, 1,1,1,2,2pentafluoropropane and 2-chloro-l, l, l-trifluoropropane.

In a preferred embodiment, the catalyst is based on a metal chosen from the group consisting of metals from columns 8 to 10 of the periodic table of the elements and rhenium. Consequently, the catalyst can be based on metals such as iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum or rhenium. More preferably, the catalyst is based on a metal chosen from nickel, palladium, rhodium, ruthenium, rhenium or platinum. Most preferably, the catalyst is based on platinum or palladium. In particular, the catalyst is based on palladium.

Preferably, the catalyst used in the present process is supported on at least one of carbon, alumina, titanium oxide, silica, zirconia or fluorides thereof, calcium fluoride, carbonate calcium, barium sulfate or zeolites. The term "carbon" in this context includes, but is not limited to, carbon, activated carbon, graphite, carbon nanotubes. The catalyst can also be unsupported such as Raney nickel.

More preferably, the catalyst can be based on platinum or palladium, in particular palladium, supported on carbon or alumina.

In a preferred embodiment, the catalyst can also comprise a cocatalyst based on another metal, for example silver, copper, gold, tellurium, zinc, chromium, molybdenum or thallium . The content of the cocatalyst can be in the range of 0.1 to 20% by weight based on the total weight of the catalyst, preferably 0.5 to 18% by weight, more preferably 1 to 15% by weight , most preferably from 2 to 10% by weight.

The catalyst can be present in any suitable form, for example in the form of a fixed or fluidized bed, preferably in the form of a fixed bed. The direction of flow can be downward or upward. The catalyst bed may further comprise a particular distribution of the catalyst so as to control the heat flows generated by the exothermic reaction. Therefore, it is possible to envisage gradients of charge density, porosity, etc., of the catalyst so as to control the exotherm of the reaction. For example, it can be envisaged for the first part of the bed to include less catalyst, while the second part comprises more.

The present process may include the step of activating the catalyst. The catalyst can be activated by subjecting the catalyst to a stream of gas containing a reducing agent. Activation can be carried out at a temperature of 50 ° C to 250 ° C. The gas stream containing a reducing agent is preferably a mixture of hydrogen and nitrogen. Before activation, the catalyst can be dried. The drying step can be carried out at a temperature of 50 ° C to 200 ° C, preferably from 80 ° C to 150 ° C. The catalyst is preferably dried under an inert atmosphere, such as nitrogen.

The present process may include the step of regenerating the catalyst. The regeneration step can comprise the treatment of the catalyst under an inert atmosphere (nitrogen, argon or helium) and / or under a stream of gas containing an oxidizing agent. The oxidizing agent can be oxygen or air. The regeneration can be carried out at a temperature in the range of 200 ° C to 800 ° C, preferably 250 ° C to 700 ° C, more preferably 300 ° C to 600 ° C, most preferably 350 ° C at 500 ° C. The catalyst can be regenerated by treating the catalyst with a gas stream containing an oxidizing agent to form an oxidized catalyst, optionally cooling the oxidized catalyst, and then treating the catalyst with a gas stream containing a reducing agent. The gas stream containing a reducing agent can be hydrogen. Treatment with the stream of gas containing a reducing agent can be carried out at a temperature of 50 ° C to 250 ° C. The gas stream containing a reducing agent is preferably a mixture of hydrogen and nitrogen.

The step of contacting the mixture comprising 2-chloro-1,1,1,2tetrafluoropropane and 2-chloro-3,3,3-trifluoropropene, and optionally 1,1,1,2,2pentafluoropropane, with hydrogen can be conducted at a temperature of 20 to 200 ° C, preferably 50 ° C to 150 ° C, more preferably 50 ° C to 100 ° C. The hydrogenation step is exothermic. The reaction temperature can be controlled using means provided for this purpose in the reactor, if necessary. The temperature can vary by a few tens of degrees during the reaction. For example, the inlet temperature can be in the range of 20 ° C to 250 ° C, and the temperature gain can be in the range of 5 ° C to 100 ° C.

The step of contacting the mixture comprising 2-chloro-1,1,1,2tetrafluoropropane and 2-chloro-3,3,3-trifluoropropene, and optionally 1,1,1,2,2pentafluoropropane, with hydrogen can be conducted at an absolute pressure of 0.1 to bar, preferably from 0.5 to 20 bar, more preferably from 1 to 20 bar, most preferably from 1 to 15 bar, in particular from 1 to 10 bar, more particularly from 1 to 5 bar.

The step of contacting the mixture comprising 2-chloro-1,1,1,2tetrafluoropropane and 2-chloro-3,3,3-trifluoropropene, and optionally 1,1,1,2,2pentafluoropropane, with hydrogen can be conducted at a contact time, being defined as the ratio between the volume of catalyst and the total charge current, from 0.1 to 100 seconds, preferably from 0.5 to 50 seconds, more preferably from 1 to 40 seconds, most preferably from 1 to 30 seconds, in particular from 1 to 20 seconds, more particularly from 2 to 10 seconds.

The step of bringing the mixture into contact comprising 2-chloro-1,1,1,2tetrafluoropropane and 2-chloro-3,3,3-trifluoropropene, and optionally 1,1,1,2,2pentafluoropropane, with hydrogen can be carried out at a molar / organic ratio, preferably H2 / 2-chloro-3,3,3-trifluoropropene, from 1 to 50, preferably from 1.5 to 20, more preferably from 2 to 15, most preferably from 3 to 10, in particular from 3 to 7. A high ratio will lead to dilution, and therefore to better management of the reaction exotherm.

In a particular embodiment, 3,3,3-trifluoropropene is also produced as a by-product.

The present process can include a step of purifying 2-chloro-1,1,1,2tetrafluoropropane. The purification can be carried out by distillation in order to separate the 2-chloro-1,1,1,2-tetrafluoropropane from the unreacted by-products and / or starting materials.

It is possible to control the exotherm of the hydrogenation reaction while maintaining very good conversion and selectivity and / or to reduce the deactivation of the catalyst.

Consequently, in a preferred embodiment, the present method can comprise the steps of:

(i) reaction of a mixture comprising 2-chloro-3,3,3-trifluoropropene and 2chloro-1,1,1,2-tetrafluoropropane, and optionally 1,1,1,2,2pentafluoropropane, in phase gaseous with hydrogen in the presence of a catalyst, (ii) recovering a first stream comprising 2-chloro-1,1,1-trifluoropropane,

2-chloro-1,1,1,2-tetrafluoropropane, optionally 1,1,1,2,23056210 pentafluoropropane, unreacted hydrogen, and optionally 2-chloro3,3,3-trifluoropropene n '' having not reacted, (iii) recycling a first part of said first flow to step (i), (iv) recovering a mixture comprising 2-chloro-1,1,1-trifluoropropane and 2- chloro-1,1,1,2-tetrafluoropropane from the remaining part of the first stream, optionally after a washing step.

Preferably, the first stream recovered in step ii) further comprises 3,3,3trifluoropropene.

More preferably, the remaining part of the first stream further comprises 3,3,3trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane, and 2-chloro-1,1,1trifluoropropane is recovered from said remaining part of the first stream by purification, preferably by distillation.

The purification, preferably by distillation, can be carried out so that a second stream comprising 2-chloro-1,1,1,2-tetrafluoropropane, 3,3,3-trifluoropropene and optionally 1,1,1 , 2,2-pentafluoropropane, and a third stream comprising 2chloro-1,1,1-trifluoropropane are formed. The second stream can be further purified, preferably by distillation, to form a stream comprising 2-chloro-1,1,1,2tetrafluoropropane and a stream comprising 3,3,3-trifluoropropene and optionally

1,1,1,2,2-pentafluoropropane. Alternatively, the purification, preferably by distillation, can be carried out so that a second stream comprising 3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane; and a third stream comprising 2-chloro-1,1,1-trifluoropropane and 2-chloro-1,1,1,2-tetrafluoropropane are formed. In this variant, the third stream is separated, preferably by distillation, to form a stream comprising 2-chloro-1,1,1,2-tetrafluoropropane and a stream comprising 2-chloro-1,1,1trifluoropropane.

In a particular embodiment, the present method can comprise the steps of:

(i) reaction of a mixture comprising 2-chloro-3,3,3-trifluoropropene, 2chloro-1,1,1,2-tetrafluoropropane, in the gas phase with hydrogen in the presence of a catalyst, (ii) recovery of a first stream comprising 2-chloro-1,1,1-trifluoropropane, 2-chloro-l, 1,1,2-tetrafluoropropane, unreacted hydrogen, and optionally 2 -chloro-3,3,3-trifluoropropene unreacted, (iii) purification, preferably by distillation, of the first stream to form a stream comprising 2-chloro-l, l, l-trifluoropropane and 2- chloro-1,1,1,2tetrafluoropropane, and a stream comprising unreacted hydrogen and optionally unreacted 2-chloro-3,3,3-trifluoropropene, (iv) recycling the stream comprising unreacted hydrogen, and optionally unreacted 2-chloro-3,3,3-trifluoropropene, to step (i), (v) recovering the stream comprising 2-chloro- l, 1,1-trifluoropropane and 2chloro-l, l, l, 2-tetrafluo ropropane.

Preferably, the mixture brought into contact with hydrogen in step (i) further comprises 1,1,1,2,2-pentafluoropropane.

More particularly, the first stream recovered in step ii) further comprises 3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane. Depending on the operating conditions used in step (iii), 3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane can be in the stream comprising 2-chloro-1,1, 1 trifluoropropane and 2-chloro-1,1,1,2-tetrafluoropropane or in the stream comprising unreacted hydrogen and optionally unreacted 2-chloro-3,3,3-trifluoropropene. Preferably, 3,3,3-trifluoropropene and optionally 1,1,1,2,2pentafluoropropane are in the stream comprising unreacted hydrogen, and optionally 2-chloro-3,3,3 - unreacted trifluoropropene. The stream comprising 2chloro-1,1,1-trifluoropropane and 2-chloro-1,1,1,2-tetrafluoropropane can be purified, preferably by distillation, to form a fourth stream comprising 2-chloro-1, 1.1 trifluoropropane and a fifth stream comprising 2-chloro-1,1,1,2-tetrafluoropropane.

The distillation can preferably be carried out in a standard distillation column at atmospheric pressure, at atmospheric pressure or under vacuum. Preferably, the pressure is less than about 20 bar, more preferably less than about 10 bar and, most preferably, less than 7 bar.

In another particular embodiment, the present method can comprise the steps of:

(i) reaction of a mixture comprising 2-chloro-3,3,3-trifluoropropene and 2chloro-1,1,1,2-tetrafluoropropane in the gas phase with hydrogen in the presence of a catalyst.

(ii) recovery of a first stream comprising 2-chloro-l, l, ltrifluoropropane, 2-chloro-l, l, l, 2-tetrafluoropropane and unreacted hydrogen, (iii) purification , preferably by a condensation step, the first stream to form an uncondensed stream comprising unreacted hydrogen and a condensed stream comprising 2-chloro-l, l, l-trifluoropropane and 2chloro-l , l, l, 2-tetrafluoropropane, and (iv) optionally, recycling the non-condensed stream comprising unreacted hydrogen to step (i), (v) recovering the condensed stream comprising 2-chloro -l, l, l-trifluoropropane and 2-chloro-l, l, l, 2-tetrafluoropropane, (vi) optionally, purification, preferably by distillation, of the condensed stream comprising 2-chloro-l, l, l -trifluoropropane and 2-chloro-1,1,1,2tetrafluoropropane to form a stream comprising 2-chloro-1,1,1trifluoropropane and a stream comprising 2-chloro-1,1,1,2-tetrafluoropropane.

Preferably, the mixture brought into contact with hydrogen in step (i) further comprises 1,1,1,2,2-pentafluoropropane. More particularly, the first stream recovered in step ii) further comprises 3,3,3-trifluoropropene and optionally

1,1,1,2,2-pentafluoropropane.

Preferably, the condensation step is carried out at a temperature between 0 and 50 ° C and at a pressure between 0.5 and 20 bar absolute, advantageously between 1 and 5 bar absolute. The distillation can preferably be carried out in a standard distillation column at atmospheric pressure, at atmospheric pressure or under vacuum. Preferably, the pressure is less than about 20 bar, more preferably less than about 10 bar and, most preferably, less than 7 bar.

Preferably, when the first stream comprises 3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane, the non-condensed stream formed further comprises 3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane.

Alternatively, when the first stream comprises 3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane, the condensed stream formed further comprises 3,3,3-trifluoropropene and optionally 1 , 1,1,2,2-pentafluoropropane. The condensed stream is purified, preferably by distillation, so that a stream comprising 2chloro-1,1,1,2-tetrafluoropropane, 3,3,3-trifluoropropene and optionally 1,1,1,2, 23056210 ll pentafluoropropane; and a stream comprising 2-chloro-1,1,1-trifluoropropane are formed. The stream comprising 2-chloro-1,1,1,2-tetrafluoropropane, 3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane can be further purified, preferably by distillation to form a stream comprising 2-chloro-1,1,1,2-tetrafluoropropane and a stream comprising 3,3,3-trifluoropropene and optionally 1,1,1,2,2pentafluoropropane. Alternatively, the purification, preferably by distillation, of the condensed stream can be carried out so that a stream comprising 3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane and a stream comprising 2-chloro-1,1,1 trifluoropropane and 2-chloro-1,1,1,2-tetrafluoropropane are formed. In this variant, the stream comprising 2-chloro-1,1,1-trifluoropropane and 2-chloro-1,1,1,2tetrafluoropropane is separated, preferably by distillation, to form a stream comprising 2-chloro- 1,1,2,2-tetrafluoropropane and a stream comprising 2-chloro-1,1,1trifluoropropane.

The gas stream comprising the recycling loop and the reactants can be preheated before introduction into the reactor. An adiabatic reactor is preferably used.

Example - Hydrogenation of a mixture comprising 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).

A tubular reactor is loaded with 10 g of a 0.5% Pd / C wet granule type catalyst. The reactor is housed inside an electric oven. The catalyst is first dried under nitrogen at 110 ° C and at atmospheric pressure. Then, the catalyst is reduced by introducing hydrogen into the nitrogen stream and maintaining the temperature at 110 ° C. After 2 hours, the bed temperature is lowered to 80 ° C., the nitrogen flow rate is reduced to zero and a mixture comprising 38.4% by weight of 2-chloro-3,3,3-trifluoropropene (HCFO1233xf), 40.2% by weight of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and 21.4% by weight of 1,1,1,2,2-pentafluoropropane (HFC-245cb) is fed into the reactor at atmospheric pressure. These feed flows are regulated and regulated by means of mass flow regulators. The molar ratio of hydrogen to organic material is 5.2. The contact time is approximately 5.3 seconds. The conversion of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) is approximately 100.0%. The selectivity for the desired 2-chloro-1,1,1-trifluoropropane (HCFC-253db) product is approximately 91.6%. The main by-product is

3,3,3-trifluoropropene (HFO-1243zf). The 2-chloro-1,1,1-trifluoropropane (boiling point 29 ° C) and the 2-chloro-1,1,1,2-tetrafluoropropane (boiling point 14 ° C) are separated by distillation.

Claims (10)

Claims 1. Process for the separation of 2-chloro-1,1,1,2-tetrafluoropropane and 2-chloro-3,3,3trifluoropropene comprising the step of bringing into contact a mixture comprising 2chloro-3,3, 3-trifluoropropene and 2-chloro-1,1,1,2-tetrafluoropropane with hydrogen in the presence of a catalyst to form a reaction mixture comprising 2-chloro1.1.1.2- tetrafluoropropane and 2- chloro-1,1,1-trifluoropropane. 2. Method according to the preceding claim further comprising the step of distilling the reaction mixture comprising 2-chloro-l, 1,1,2-tetrafluoropropane and 2-chloro-l, 1,1trifluoropropane obtained to form a flow comprising 2-chloro-1,1,1,2tetrafluoropropane and a stream comprising 2-chloro-1,1,1-trifluoropropane. 3. Method according to any one of the preceding claims, in which the catalyst is based on a metal chosen from the group consisting of metals from columns 8 to 10 of the periodic table of the elements and rhenium. 4. Method according to any one of the preceding claims, in which the catalyst is based on a metal chosen from the group consisting of nickel, palladium, rhodium, ruthenium, rhenium and platinum. 5. Method according to any one of the preceding claims, in which 3,3,3trifluoropropene is also produced as a by-product in the reaction mixture. 6. Method according to any one of the preceding claims, in which the step of bringing the mixture of 2-chloro-3,3,3-trifluoropropene and 2-chloro-1,1,1,2tetrafluoropcopane into contact with l hydrogen is conducted at a temperature of 20 to 200 ° C. 7. Method according to any one of the preceding claims, said method comprising the steps of: (i) reaction of a mixture comprising 2-chloro-3,3,3-trifluoropropene and 2-chloro1.1.1.2- tetrafluoropropane, and optionally 1,1,1,2,2-pentafluoropropane, in phase gaseous with hydrogen in the presence of a catalyst, (ii) recovery of a first stream comprising 2-chloro-l, l, l-trifluoropropane, 2chloro-l, l, l, 2-tetrafluoropropane, optionally 1,1,1,2,2-pentafluoropropane, unreacted hydrogen, and optionally unreacted 2-chloro-3,3,3-trifluoropropene, (iii) recycling a first part of said first flow to stage (i), (iv) recovery of a mixture comprising 2-chloro-1,1,1-trifluoropropane and 2-chloro1,1,1,2-tetrafluoropropane from the remaining part of the first stream, optionally after a washing step. 8. Method according to any one of the preceding claims, in which the first stream further comprises 3,3,3-trifluoropropene. 9. Method according to the preceding claim wherein the remaining part of the first stream further comprises 3,3,3-trifluoropropene and optionally 1,1,1,2,2pentafluoropropane; and wherein the 2-chloro-1,1,1,2-tetrafluoropropane is recovered from said remaining part of the first stream by purification, preferably by distillation. 10. Method according to any one of the preceding claims, in which said catalyst is supported on at least one of carbon, alumina, titanium oxide, silica, zirconia or fluorides thereof, calcium fluoride, calcium carbonate, barium sulfate or zeolites.