Technical area
The present invention relates to compositions comprising l-chloro-2,2-difluoroethane. In particular, the invention relates to compositions comprising 1-chloro-2,2-difluoroethane and 1,1-dichloroethylene. More particularly, the invention relates to azeotropic or near-azeotropic compositions comprising l-chloro-2,2-difluoroethane and 1,1-dichloroethylene.
BACKGROUND OF THE INVENTION
The fluids foundation halocarbons have found many applications in various industrial fields, such as heat transfer fluid, propellants, foaming agents, blowing agents, gaseous dielectrics, polymerization medium or monomer, support fluids, agents abrasives, drying agents and fluids for energy production unit. WO 2015/082812 discloses a method for manufacturing 1-chloro-2,2-difluoroethane.

The advantage of using azeotropic or near-azeotropic fluids lies in the absence of splitting during the evaporation process and in that they act (virtually) as a pure substance. However it is difficult to identify new fluids with these characteristics, since azeotropes are not predictable.

Summary of the Invention

The present invention provides an azeotropic composition or quasi-azeotropic comprising l-chloro-2,2-difluoroethane and 1,1-dichloroethylene.

According to a preferred embodiment, said composition comprises 1 to 99 mol% of l-chloro-2,2-difluoroethane and from 99 to 1 mol% of 1,1-dichloroethylene based on the total composition thereof expressed mol.

According to a preferred embodiment, the boiling temperature of said composition is between 30 ° C and 116 ° C.

According to a preferred embodiment, the pressure is between 1 and 11 bara.

According to a preferred embodiment, said composition comprises 37 to 67% mole of l-chloro-2,2-difluoroethane and from 33 to 63% mole of 1,1-dichloroethylene based on the total composition thereof expressed mol. Preferably, the composition is azeotropic.

According to a preferred embodiment, said composition comprises trans-1,2-dichloroethylene.

According to a preferred embodiment, said composition consists of l-chloro-2,2-difluoroethane and 1,1-dichloroethylene.

According to a preferred embodiment, said composition consists of l-chloro-2,2-difluoroethane, 1,1-dichloroethylene and trans-l, 2-dichloroethylene.

According to a preferred embodiment, the molar ratio of l-chloro-2,2-difluoroethane and trans-l, 2-dichloroethylene is between 3 and 30.

According to a second aspect, the present invention provides a process for preparing a composition comprising l-chloro-2,2-difluoroethane and 1,1-dichloroethylene comprising (i) at least one step during which the 1, 1,2-trichloroethane reacts with hydrofluoric acid in the gas phase optionally in the presence of an oxidizing agent and in the presence or absence of a fluorination catalyst to give a stream comprising 1-chloro-2, 2-difluoroethane, hydrochloric acid, hydrofluoric acid and at least one compound (s) chosen (s) among 1,2-dichloroethylenes (cis and trans), 1-chloro, 2-fluoroethylenes (cis and trans), the l, 2-dichloro-2-fluoroethane and unreacted 1,1,2-trichloroethane; (Ii) at least one step of separation of the compounds from the reaction step to give a first stream comprising hydrochloric acid and a second stream comprising hydrofluoric acid, l-chloro-2,2-difluoroethane, at least one compound (s) and unreacted 1,1,2-trifluoroethane; (Iii) at least one step of separating the second stream to give a PI organic phase comprising l-chloro-2,2-difluoroethane, at least one compound (s) and unreacted 1,1,2-trichloroethane and an inorganic phase P 2 comprising HF; (Iv) at least one step of purifying the organic phase PI obtained in (iii); characterized in that step (iv) comprises:

a) washing the organic phase PI obtained in step (iii) to form an organic phase Bl comprising l-chloro-2,2-difluoroethane, at least one compound (s), 1,1,2-trichloroethane and unreacted 1,1-dichloroethylene; and a non-organic phase B2 comprising hydrofluoric acid;

b) optionally, drying the organic phase Bl obtained in step a) to form an organic phase B3 comprising l-chloro-2,2-difluoroethane, at least one compound (s), 1,1,2-trichloroethane and unreacted 1,1-dichloroethylene;

c) purification, preferably by distillation, from the organic phase Bl or B3 of the organic phase to form a B4 stream comprising l-chloro-2,2-difluoroethane and 1,1-dichloroethylene; and B5 organic phase comprising the unreacted 1,1,2-trichloroethane and at least one compound (s).

According to a preferred embodiment, the washing step a) is performed with water and the non-organic phase is an aqueous phase B2.

According to a preferred embodiment, step a) is conducted at a temperature between 0 ° C and 30 ° C at a pressure between 1 and 4 bara.

Detailed Description of the Invention

The present invention relates to a composition comprising l-chloro-2,2-difluoroethane and 1, 1-dichloroethylene. Preferably, said composition is azeotropic or near-azeotropic.

The term "near-azeotropic" has a broad meaning and is intended to include compositions that are strictly azeotropic and those that behave as an azeotropic mixture.

The volatility of a compound A is represented by the ratio of the mole fraction in the gas phase (y A ) on the mole fraction in liquid phase (x A ) in equilibrium conditions (at equilibrium pressure and temperature): a = y a / XA. The volatility of a compound B is represented by the ratio of the mole fraction in the gas phase (y B ) of the mole fraction in liquid phase (x B ) in equilibrium conditions (at equilibrium pressure and temperature): a = ye / ΧΒ · the relative volatility measures the ease of separation of two compounds a and B. it is the ratio of volatilities of the two compounds: OA, B = yA XB / YB XA. The higher the volatility, the higher the mixture is easily separable.

When the relative volatility is equal to 1, or between 0.95 and 1.05, this means that the mixture is azeotropic. When the relative volatility is 0.85 to 1, 15, this means that the mixture is quasiazeotropic.

Said composition may comprise from 1 to 99 mol% of l-chloro-2,2-difluoroethane based on the total composition thereof expressed by mol. Preferably said composition may comprise 1 mol% of l-chloro-2,2-difluoroethane, 2 mol%, 3 mol%, 4 mol%, 5 mol%, 6 mol%, 7 mol%, 8 mol% 9 mol% 10 mol% 11 mol% 12 mol% 13 mol% 14 mol% 15 mol% 16 mol% 17 mol% 18 mol% 19 mol% 20 mol% 21 mol% , 22 mol%, 23 mol%, 24%

mol, 25 mol% 26 mol% 27 mol% 28 mol% 29 mol% 30 mol% 31 mol% 32 mol% 33 mol% 34 mol% 35 mol% 36 mol%, 37 mol% 38 mol% 39 mol% 40 mol% 41 mol% 42 mol% 43 mol% 44 mol% 45 mol% 46 mol% 47 mol% 48 mol% 49% mol, 50 mol%, 51 mol% 52 mol% 53 mol% 54 mol% 55 mol% 56 mol% 57 mol% 58 mol% 59 mol% 60 mol%, 61 mol%, 62 mol% 63 mol% 64 mol% 65 mol% 66 mol% 67 mol% 68 mol% 69 mol% 70 mol% 71 mol% 72 mol% 73 mol% 74% mol, 75 mol% 76 mol% 77 mol% 78 mol% 79 mol% 80 mol% 81 mol% 82 mol% 83 mol% 84 mol% 85 mol% 86 mol%, 87 mol% 88 mol% 89 mol% 90 mol% 91 mol% 92 mol% 93 mol% 94 mol% 95 mol% 96 ​​mol% 97 mol%, 98 mol% or 99% molar l-chloro-2,2 difluoroethane based on the total composition thereof expressed by mol.

Said composition may comprise from 1 to 99 mol% of 1,1-dichloroethylene based on the total composition expressed in moles. Preferably said composition may comprise 1 mol% of 1,1-dichloroethylene, 2 mol%, 3 mol%, 4 mol%, 5 mol%, 6 mol%, 7 mol%, 8 mol%, 9 mol%, 10 mol% 11 mol% 12 mol% 13 mol% 14 mol% 15 mol% 16 mol% 17 mol% 18 mol% 19 mol% 20 mol% 21 mol% 22 mol% 23 mol% 24 mol% 25 mol% 26 mol% 27 mol% 28 mol% 29 mol% 30 mol% 31 mol% 32 mol% 33 mol% 34 mol% 35 mol% 36 mol% 37 mol% 38 mol% 39 mol% 40 mol% 41 mol% 42 mol% 43 mol% 44 mol% 45 mol% 46 mol% 47 mol% 48 mol% 49 mol% 50 mol% 51 mol% 52 mol% 53 mol% 54 mol% 55 mol% 56 mol% 57 mol% 58 mol% 59 mol% 60 mol% 61 mol% 62 mol% 63 mol% 64 mol% 65 mol% 66 mol% 67 mol% 68 mol% 69 mol% 70 mol% 71 mol% 72% mola IRE, 73 mol% 74 mol% 75 mol% 76 mol% 77 mol% 78 mol% 79 mol% 80 mol% 81 mol% 82 mol% 83 mol% 84 mol%, 85 mol% 86 mol% 87 mol% 88 mol% 89 mol% 90 mol% 91 mol% 92 mol% 93 mol% 94 mol% 95 mol% 96 ​​mol% 97% mole, 98 mole% or 99 mole% 1,1-dichloroethylene based on the total composition thereof expressed by mol.

More preferably, said composition may comprise 1 mol%, 2 mol%, 3 mol%, 4 mol%, 5 mol%, 6 mol%, 7 mol%, 8 mol%, 9 mol%, 10 mol%, 11 mol% 12 mol% 13 mol% 14 mol% 15 mol% 16 mol% 17 mol% 18 mol% 19 mol% 20 mol% 21 mol% 22 mol% 23 mol% 24 mol% 25 mol% 26 mol% 27 mol% 28 mol% 29 mol% 30 mol% 31 mol% 32 mol% 33 mol% 34 mol% 35 mol% 36 mol% 37 mol% 38 mol% 39 mol% 40 mol% 41 mol% 42 mol% 43 mol% 44 mol% 45 mol% 46 mol% 47 mol% 48 mol% 49 mol% 50 mol% 51 mol% 52 mol% 53 mol% 54 mol% 55 mol% 56 mol% 57 mol% 58 mol% 59 mol% 60 mol%, 61 mol% , 62 mol% 63 mol% 64 mol% 65 mol% 66 mol% 67 mol% 68 mol% 69 mol% 70 mol% 71 mol% 72 mol% 73 mol% 74 mol% 75 mol% 76 mol% 77 mol% 78 mol% 79 mol% 80 mol% 81 mol% 82 mol% 83 mol% 84 mol% 85 mol% 86 mol% 87 mol% 88 mol% 89 mol% 90 mol% 91 mol% 92 mol% 93 mol% 94 mol% 95 mol% 96 ​​mol% 97 mol% 98 mol% or 99 mole% of l-chloro-2,2-difluoroethane and 1 mol%, 2 mol%, 3 mol%, 4 mol%, 5 mol%, 6 mol%, 7 mol%, 8 mol%, 9 mol% 10 mol% 11 mol% 12 mol% 13 mol% 14 mol% 15 mol% 16 mol% 17 mol% 18 mol% 19 mol% 20 mol% 21 mol% 22 mol% 23 mol% 24 mol% 25 mol% 26 mol% 27 mol% 28 mol% 29 mol% 30 mol% 31 mol% 32 mol% 33 mol% 34 mol% 35 mol% 36 mol% 37 mol% 38 mol% 39 mol% 40 mol% 41 mol% 42 mol% 43 mol% 44 mol% 45 mol% 46 mol% 47 mol%, 48 mol%, 49% Mola'i re, 50 mol%, 51 mol% 52 mol% 53 mol% 54 mol% 55 mol% 56 mol% 57 mol% 58 mol% 59 mol% 60 mol%, 61 mol%, 62 mol% 63 mol% 64 mol% 65 mol% 66 mol% 67 mol% 68 mol% 69 mol% 70 mol% 71 mol% 72 mol% 73 mol% 74% mol, 75 mol% 76 mol% 77 mol% 78 mol% 79 mol% 80 mol% 81 mol% 82 mol% 83 mol% 84 mol% 85 mol% 86 mol%, 87 mol% 88 mol% 89 mol% 90 mol% 91 mol% 92 mol% 93 mol% 94 mol% 95 mol% 96 ​​mol% 97 mol%, 98 mol% or 99% mole of 1,1-dichloroethylene based on the total composition thereof expressed by mol.

In particular, said composition may comprise from 2 to 98 mol% of l-chloro-2,2-difluoroethane, of 3 to 97 mol%, 4-96 mol%, 5-95 mol%, 6-94% molar, 7-93 mol%, 8-92 mol%, 9-91 mol%, 10-90 mol%, 11-89 mol%, 12-88 mol%, 13-87 mol% , of 14-86 mol%, 15-85 mol%, 16-84 mol%, 17-83 mol%, 18-82 mol%, 19-81 mol%, 20-80 mol%, of 21-79 mol%, 22-78 mol%, 23-77 mol%, 24-76 mol%, 25-75 mol%, 26-74 mol%, 27-73 mol%, 28-72 mol%, 29-71 mol%, 30-70 mol%, 31-69 mol%, 32-68 mol%, 33-67 mol%, 34-67 mol%, 35 to 67 mol%, 36-67 mol% or 37-67 mol% of l-chloro-2,2-difluoroethane based on the total composition thereof expressed by mol.

In particular, said composition may comprise from 2 to 98 mol% of 1,1-dichloroethylene, from 3 to 97 mol%, 4-96 mol%, 5-95 mol%, 6-94 mol%, 7 to 93 mol%, 8-92 mol%, 9-91 mol%, 10-90 mol%, 11-89 mol%, 12-88 mol%, 13-87 mol%, 14 to 86 mol%, 15-85 mol%, 16-84 mol%, 17-83 mol%, 18-82 mol%, 19-81 mol%, 20-80 mol%, 21-79 mol%, 22-78 mol%, 23-77 mol%, 24-76 mol%, 25-75 mol%, 26-74 mol%, 27-73 mol%, 28-72% molar, 29-71 mol%, 30-70 mol%, 31-69 mol%, 32-68 mol%, 33-67 mol%, 33-66 mol%, 33-65 mol% from 33 to 64% molar or from 33 to 63% mole of 1,1-dichloroethylene based on the total composition thereof expressed by mol.

Thus according to a particular embodiment of the present invention, said composition may comprise from 2 to 98 mol%, 3-97 mol%, 4-96 mol%, 5-95 mol%, 6-94 mol%, 7-93 mol%, 8-92 mol%, 9-91 mol%, 10-90 mol%, 11-89 mol%, 12-88 mol%, 13-87 mol%, 14 to 86 mol%, 15-85 mol%, 16-84 mol%, 17-83 mol%, 18-82 mol%, 19-81 mol%, 20-80 mol%, 21 to 79 mol%, 22-78 mol%, 23-77 mol%, 24-76 mol%, 25-75 mol%, 26-74 mol%, 27-73 mol%, 28-72 mol%, 29-71 mol%, 30-70 mol%, 31-69 mol%, 32-68 mol%, 33-67 mol%, 34-66 mol%, 34-67% molar, 35-67 mol%, 36-67 mol% or 37-67 mol% of l-chloro-2,2-difluoroethane and 2 to 98 mol%, 3 to 97 mol%, from 4 to 96 mo% lar, from 5 to 95 mol%, 6-94 mol%, 7-93 mol%, 8-92 mol%, 9-91 mol%, 10-90 mol%, 11-89 mol% , of 12-88 mol%, 13-87 mol%, 14-86 mol%, 15-85 mol%, 16-84 mol%, 17-83 mol%, 18-82 mol%, of 19-81 mol%, 20-80 mol%, 21-79 mol%, 22-78 mol%, 23-77 mol%, 24-76 mol%, 25-75 mol%, 26-74 mol%, 27-73 mol%, 28-72 mol%, 29-71 mol%, 30-70 mol%, 31-69 mol%, 32-68 mol%, 33 to 67 mol%, 33-66 mol%, 33-65 mol%, 33-64 mol% or 33-63 mol% 1,1-dichloroethylene based on the total composition thereof expressed in mole.

Preferably, the boiling temperature of said composition is between -50 ° C and 250 ° C, more preferably between -20 ° C and 185 ° C, in particular between 5 ° C and 145 ° C. More particularly, the boiling temperature of said composition is between 30 ° C and 116 ° C.

Preferably, the pressure is 0.005 bar to 20 bar, particularly preferably from 0.3 bar to 15 bar abs. In particular, the pressure is between 1 and 11 bar abs.

Thus, the boiling temperature of said composition is between -50 ° C and 250 ° C, more preferably between -20 ° C and 185 ° C, in particular between 5 ° C and 145 ° C, more particularly between 30 ° C and 116 ° C at a pressure between 0.005 bar to 20 bar, particularly preferably from 0.3 bar to 15 bar, more particularly between 1 and 11 bar abs.

According to a preferred embodiment, said composition comprises 37 to 67% mole of l-chloro-2,2-difluoroethane and from 33 to 63% mole of 1,1-dichloroethylene based on the total composition thereof expressed mol.

Preferably, said composition comprises 37 to 67% mole of l-chloro-2,2-difluoroethane and from 33 to 63% mole of 1,1-dichloroethylene based on the total composition thereof expressed by mol, in which the boiling temperature of said composition is between 30 ° C and 116 ° C at a pressure between 1 and 11 bara. Preferably, said composition in the proportions and conditions expressed herein is azeotropic.

According to a particular embodiment, said composition consists of l-chloro-2,2-difluoroethane and 1,1-dichloroethylene, in the above detailed proportions. 1-chloro-2,2-difluoroethane and 1,1-dichloroethylene may be separated by extractive distillation to form a composition of l-chloro-2,2-difluoroethane high purity.

According to a preferred embodiment, said composition may also include trans-l, 2-dichloroethylene. When the composition comprises the trans-l, 2-dichloroethylene, the molar ratio of l-chloro-2,2-difluoroethane and trans-l, 2-dichloroethylene may be between 3 and 30. Thus, a ternary composition comprising , preferably consisting of, l-chloro-2,2-difluoroethane, 1,1-dichloroethylene and trans-l, 2-dichloroethylene is provided. Proportions, the boiling point and pressure are as detailed above. Thus, advantageously, said composition comprises, preferably consists of:

• from 2 to 98 mol% of l-chloro-2,2-difluoroethane, of 3 to 97 mol%, 4-96 mol%, 5-95 mol%, 6-94 mol%, 7-93 mol%, 8-92 mol%, 9-91 mol%, 10-90 mol%, 11-89 mol%, 12-88 mol%, 13-87 mol%, 14-86% molar, from 15 to 85 mol%, 16-84 mol%, 17-83 mol%, 18-82 mol%, 19-81 mol%, 20-80 mol%, 21-79 mol% , of 22-78 mol%, 23-77 mol%, 24-76 mol%, 25-75 mol%, 26-74 mol%, 27-73 mol%, 28-72 mol%, of 29-71 mol%, 30-70 mol%, 31-69 mol%, 32-68 mol%, 33-67 mol%, 34-67 mol%, 35-67 mol%, 36-67 mol% or 37-67 mol% of l-chloro-2,2-difluoroethane;

• from 2 to 98 mol% of 1,1-dichloroethylene, from 3 to 97 mol%, 4-96 mol%, 5-95 mol%, 6-94 mol%, 7-93 mol%, 8-92 mol%, 9-91 mol%, 10-90 mol%, 11-89 mol%, 12-88 mol%, 13-87 mol%, 14-86 mol%, 15 to 85 mol%, 16-84 mol%, 17-83 mol%, 18-82 mol%, 19-81 mol%, 20-80 mol%, 21-79 mol%, 22 to 78 mol%, 23-77 mol%, 24-76 mol%, 25-75 mol%, 26-74 mol%, 27-73 mol%, 28-72 mol%, 29-71 mol%, 30-70 mol%, 31-69 mol%, 32-68 mol%, 33-67 mol%, 33-66 mol%, 33-65 mol%, 33-64% molar or from 33 to 63% mole of 1,1-dichloroethylene; and

• trans-l, 2-dichloroethylene, the molar ratio of l-chloro-2,2-difluoroethane and trans-l, 2-dichloroethylene may be between 3 and 30;

based on the total composition thereof expressed by mol.

The boiling temperature of said composition comprising l-chloro-2,2-difluoroethane, 1,1-dichloroethylene and trans-l, 2-dichloroethylene is between -50 ° C and 250 ° C, more preferably between -20 ° C and 185 ° C, in particular between 5 ° C and 145 ° C, more particularly between 30 ° C and 116 ° C at a pressure between 0.005 bar to 20 bar, particularly preferably from 0.3 bar to 15 bar, more particularly between 1 and 11 bar absolute.

According to a second aspect of the present invention, a method for preparing a composition comprising l-chloro-2,2-difluoroethane and 1,1-dichloroethylene is provided.

Said method comprises (i) at least one step in which 1,1,2-trichloroethane reacts with gas phase hydrofluoric acid optionally in the presence of an oxidizing agent and in the presence or absence of a fluorination catalyst to give a stream comprising l-chloro-2,2-difluoroethane, hydrochloric acid, hydrofluoric acid and at least one compound (s) chosen (s) from 1.2 -dichloroéthylènes (cis and trans), 1-chloro, 2-fluoroethylenes (cis and trans), the l, 2-dichloro-2-fluoroethane and unreacted 1,1,2-trichloroethane; (Ii) at least one step of separation of the compounds from the reaction step to give a first stream comprising hydrochloric acid and a second stream comprising hydrofluoric acid, l-chloro-2,2-difluoroethane, at least one compound (s) and unreacted 1,1,2-trifluoroethane; (Iii) at least one step of separating the second stream to give a PI organic phase comprising l-chloro-2,2-difluoroethane, at least one compound (s) and unreacted 1,1,2-trichloroethane and an inorganic phase P 2 comprising HF; (Iv) at least one step of purifying the organic phase PI obtained in (iii); characterized in that step (iv) comprises:

a) washing the organic phase PI obtained in step (iii) to form an organic phase Bl comprising l-chloro-2,2-difluoroethane, at least one compound (s), 1,1,2-trichloroethane and unreacted 1,1-dichloroethylene; and a non-organic phase B2 comprising hydrofluoric acid;

b) optionally, drying the organic phase Bl obtained in step a) to form an organic phase B3 comprising l-chloro-2,2-difluoroethane, at least one compound (s), 1,1,2-trichloroethane and unreacted 1,1-dichloroethylene;

c) purification, preferably by distillation, from the organic phase Bl or B3 of the organic phase to form a B4 stream comprising l-chloro-2,2-difluoroethane and

1,1-dichloroethylene; and B5 organic phase comprising the unreacted 1,1,2-trichloroethane and at least one compound (s) A.

preferably a catalyst is used in step (i) and advantageously in the presence of an oxidizing agent. The temperature of the reaction step is preferably between 150 and 400 ° C, preferably between 200 and 350 ° C. The pressure at which the fluorination reaction is conducted is preferably between 1 and 30 bar absolute, advantageously between 3 and 20 bar absolute and more particularly between 3 and 15 bar.

The amount of hydrofluoric acid used in the reaction is preferably between 5 and 40 mol and advantageously between 10 and 30 mol per mol of HCC-140.

The contact time defined as the catalyst volume / debit total volumetric gas temperature and pressure of the reaction can be between 2 and 200 seconds, preferably between 2 and 100 seconds, preferably between 2 and 50 seconds .

The pure oxidizing agent or as a mixture with nitrogen can be selected from oxygen, and chlorine. We choose preferably chlorine.

The amount of oxidizing agent used is preferably 0.01 to 20 mol% per mole of F140, preferably between 0.01 to 0.2 mol% per mol of HCC-140.

An amount of oxidizing agent between 1 - 10 mol% relative to F140 gave very promising results.

The catalyst used can be bulk or supported. The catalyst may be based on a metal including a transition metal oxide or a derivative thereof, halide or oxyhalide of such a metal. For example, mention may be made FECU, chromium oxyfluoride, N1CI2, CrF.sub.3 and mixtures thereof.

By way of supported catalysts include those supported on carbon or magnesium base such as magnesium compounds in particular halides such as MgF2 or magnesium oxyhalides such as oxyfluorides or based on aluminum such as alumina, activated alumina or aluminum derivatives, in particular halides, such as AI F3 or oxyhalides such as aluminum oxyfluoride.

The catalyst may further comprise co-catalysts selected from Co, Zn, Mn, Mg, V, Mo, Te, Nb, Sb, Ta, P, Ni, Zr, Ti, Sn, Cu, Pd, Cd, Bi , rare earths and mixtures thereof. When the catalyst is based on chromium, Ni, Mg and Zn are advantageously selected as cocatalyst.

The atomic ratio cocatalyst / catalyst is preferably between 0.01 and 5.

The chromium-based catalysts are particularly preferred.

The catalyst used in the present invention can be prepared by coprecipitation of corresponding salts optionally in the presence of a support.

The catalyst may also be prepared by co-grinding of the corresponding oxides.

Prior to the fluorination reaction the catalyst is subjected to an activation step by THF at a temperature preferably between 100 and 450 ° C, preferably between 200 and 400 ° C for a period between 1 and 50 hours.

Furthermore THF by treatment, activation can be carried out in the presence of the oxidizing agent.

The activation steps can be carried out at atmospheric pressure or under pressure up to 20 bar absolute.

According to a preferred embodiment of the invention, the support can be prepared from highly porous alumina. In a first step alumina is converted to aluminum fluoride or a mixture of aluminum fluoride and alumina, by fluorination using air and hydrofluoric acid, the alumina conversion rate aluminum fluoride mainly dependent on the temperature at which the fluorination is carried alumina (usually between 200 ° C and 450 ° C, preferably between 250 ° C and 400 ° C). The support is then impregnated with aqueous solutions of salts of chromium, nickel and optionally rare earth metal, or with the aid of aqueous solutions of chromic acid, nickel or zinc salt, and optionally salts or rare earth oxides and methanol (as a reducing agent to chromium). As chromium salts, nickel or zinc and rare earth metals can be employed, chlorides, or other salts such as, for example, oxalates, formates, acetates, nitrates and sulphates or nickel dichromate, and of rare earth metals, provided that such salts are soluble in the amount of water capable of being absorbed by the support.

The catalyst may also be prepared by direct impregnation of alumina (which is usually enabled) using solutions of the compounds of chrome, nickel or zinc, and optionally rare earth metals mentioned above. In this case, the conversion of at least part (e.g. 70% or more) of the alumina to aluminum fluoride or aluminum oxyfluoride is performed during the metal activation step of the catalyst.

The activated aluminas which may be used for catalyst preparation are well-known products available commercially. They are generally prepared by calcination of alumina hydrate (aluminum hydroxide) at a temperature between 300 ° C and 800 ° C. Aluminas (activated or not) can contain significant levels (up to 1000 ppm) of sodium without impairing the catalytic performance.

Preferably, the catalyst is conditioned or activated, that is to say converted into active and stable components (to reaction conditions) by activating said preliminary operation. This treatment may be carried out either "in situ" (in the fluorination reactor) or in a suitable apparatus designed to withstand activation conditions.

After impregnating the carrier, the catalyst is dried at a temperature between 100 ° C and 350 ° C, preferably 220 ° C to 280 ° C in the presence of air or nitrogen.

The dried catalyst is then activated in one or two steps with hydrofluoric acid, optionally in the presence of an oxidizing agent. The duration of this stage of activation by fluorination can be between 6 and 100 hours and the temperature between 200 and 400 ° C.

Preferably, the separation step (ii) comprises at least one distillation, preferably carried out at a temperature between -60 ° and 120 ° C and more particularly between -60 and 89 ° C and an absolute pressure of between 3 abs and 20 and advantageously between 3 and 11 bar abs bar.

Addition of l-chloro-2,2-difluoroethane, hydrofluoric acid and 1,1,2-trichloroethane and the organic phase obtained in step (iii) also comprises at least one of A compound selected from the group consisting of cis-l, 2-dichloroethylene, trans-1,2-dichloroethylene, cis-l-chloro-2-fluoroethylene, 1,2-dichloro-l-fluoroethane and trans-l-chloro-2-fluoroethylene.

After separation of the second stream in step (iii), the inorganic phase obtained in (iii) preferably contains the majority of the HF initially present in the second stream with respect to the organic phase also obtained in step (iii ). The organic phase obtained in (iii) may contain hydrofluoric acid. The amount of hydrofluoric acid in the organic phase is less than the amount of hydrofluoric acid in the inorganic phase. The molar ratio of hydrofluoric acid present in the organic phase over hydrofluoric present in the inorganic acid phase is less than 1: 10, preferably less than 1: 50, especially 1: 100.

Preferably, the separation step (iii) comprises at least a decantation step, advantageously carried out at a temperature between -20 and 60 ° C and more particularly between -20 and 10 ° C.

Preferably, the washing step a) is performed with water and the non-organic phase is an aqueous phase B2. The washing step a) allows the formation of 1,1-dichloroethylene. The latter is recovered in the organic phase Bl. Preferably, step a) is conducted at a temperature between 0 ° C and 30 ° C at a pressure between 1 and 4 bar abs.

The organic phase Bl may contain H2O, preferably in a small proportion. Preferably, the content of H2O in the organic phase Bl is less than 5% by weight based on the total weight of the organic phase Bl, more preferably less than 3% by weight, in particular less than 1% by weight. And the organic phase may comprise Bl l-chloro-2,2-difluoroethane, at least one compound (s), unreacted 1,1,2-trichloroethane, 1,1-dichloroethylene and H2O.

Step b) drying the organic phase Bl may be performed at a temperature between 0 ° C and 30 ° C at a pressure between 1 and 4 bar abs. The drying step b) reduces the water content in the organic phase to form a phase Bl

organic B3 comprising l-chloro-2,2-difluoroethane, at least one compound (s), unreacted 1,1,2-trichloroethane and 1,1-dichloroethylene. Preferably, the organic phase B3 comprises less than 1000 ppm of O h, more preferably less than 100 ppm O h, in particular less than 10 ppm h O. Preferably, the drying may be carried out over molecular sieve . Alternatively, the drying may be carried out in the presence of zeolite or absorbent known to those skilled in the art.

Step c) is preferably purification by distillation. Distillation of the organic phase Bl or B3 may be carried out at a temperature of 10 to 100 ° C, preferably from 20 to 90 ° C, more preferably from 30 to 80 ° C and at an absolute pressure of 0, 3-8 bar abs, preferably from 0.5 to 6 bar absolute, more preferably from 1 to 4 bar. Step c) purification preferably allows the formation of an azeotropic composition or quasi-azeotropic comprising l-chloro-2,2-difluoroethane and 1,1-dichloroethylene as described above.

Preferably, said at least one compound (s) comprises the trans-l, 2-dichloroethylene and at least one further compound A selected from the group consisting of cis-1,2-dichloroethylene, cis-l-chloro-2- fluoroethylene, 1,2-dichloro-l-fluoroethane and trans-l-chloro-2-fluoroethylene. In particular, when step c) is a distillation purification, trans-1,2-dichloroethylene is preferably contained in the B4 stream, the latter and comprising l-chloro-2,2-difluoroethane, 1,1 -dichloroéthylène and trans-2-dichloroethylene. In this case, the organic phase comprises B5, preferably 1,1,2-trichloroethane unreacted and said at least one further compound A selected from the group consisting of cis-l, 2-dichloroethylene, cis-l-chloro- 2-fluoroethylene, 1,2-dichloro-l-fluoroethane and trans-l-chloro-2-fluoroethylene.

According to a preferred embodiment, the method also comprises a step of recycling to step (i) of the organic phase B5.

According to a preferred embodiment, the method also comprises a step of recycling to step (i) of the non-organic phase P2 from step (iii). According to one embodiment, prior to recycling to step (i), the non-organic phase P2 obtained in (iii) is purified so that the HF content is greater than or equal to 90% by weight. Preferably, this purification comprises at least one distillation, preferably carried out at a temperature between -23 and 46 ° C and an absolute pressure between 0.3 and 3 bar abs.

EXAMPLES

Experimental Procedure:

HCC-140 and / optionally 1,2-dichloroethylene and THF are fed separately in a single tube reactor made of Inconel, heated by means of a fluidised alumina bath. The pressure is regulated by means of a control valve located at the reactor outlet. The gases resulting from the reaction were analyzed by gas chromatography. The catalyst was first dried under a nitrogen stream at 250 ° C and then the nitrogen was gradually replaced by HF to complete activation with pure HF (0.5 mole / hr) at 350 ° C for 8 hours.

example 1

55g are activated as described above. HCC-140, HF and chlorine are then fed with a molar ratio of HCC-140 / HF / chlorine of from 1: 9: 0.08 (17g / h of HF) at 230 ° C, 11 bar abs, with a contact time of 54 s. The yield F142 is 60% after 5 hours. After Looh, the yield is 62%. The resulting mixture is treated for separating hydrofluoric acid from the other compounds. The obtained organic layer comprises l-chloro-2,2-difluoroethane, trans-l, 2-dichloroethylene and unreacted 1,1,2-trichloroethane. This phase is washed with water at a temperature between 0 and 30 ° C at a pressure between 1 and 4 bar abs. The aqueous phase contains non-removed residual hydrofluoric acid during the previous step. The organic phase comprises l-chloro-2,2-difluoroethane, trans-1,2-dichloroethylene, 1,1-dichloroethylene and unreacted 1,1,2-trichloroethane. The organic phase is then dried and distilled as detailed herein to form a composition comprising l-chloro-2,2-difluoroethane, trans-l, 2-dichloroethylene and 1,1-dichloroethylene.

claims
An azeotropic composition or quasi-azeotropic comprising l-chloro-2,2-difluoroethane and 1,1-dichloroethylene.
Composition according to the preceding claim comprising from 1 to 99 mol% of 1-chloro-2,2-difluoroethane and from 99 to 1 mol% of 1,1-dichloroethylene based on the total composition thereof expressed by mol.

A composition according to any preceding claim characterized in that the boiling temperature of said composition is between 30 ° C and 116 ° C.

A composition according to any preceding claim characterized in that the pressure is between 1 and 11 bara.

A composition according to any preceding claim characterized in that it comprises from 37 to 67 mol% of l-chloro-2,2-difluoroethane and from 33 to 63% mole of 1,1-dichloroethylene based on the composition total thereof expressed in moles; preferably, the composition is azeotropic.

Composition according to any one of the preceding claims characterized in that it comprises trans-l, 2-dichloroethylene.

Composition according to any one of claims 1 to 5 characterized in that it consists of l-chloro-2,2-difluoroethane and 1,1-dichloroethylene.

Composition according to any one of claims 1 to 5 characterized in that it consists of l-chloro-2,2-difluoroethane, 1,1-dichloroethylene and trans-1,2-dichloroethylene.

Composition according to the preceding claim characterized in that the molar ratio of l-chloro-2,2-difluoroethane and trans-l, 2-dichloroethylene is between 3 and 30.

10. A process for preparing a composition comprising l-chloro-2,2-difluoroethane and 1,1-dichloroethylene comprising (i) at least one step in which 1,1,2-trichloroethane reacts with gas phase hydrofluoric acid optionally in the presence of an oxidizing agent and in the presence or absence of a fluorination catalyst to give a stream comprising l-chloro-2,2-difluoroethane, acid hydrochloric, hydrofluoric acid and at least one compound (s) chosen (s) among 1,2-dichloroethylenes (cis and trans), 1-chloro, 2-fluoroethylenes (cis and trans), 1,2 - dichloro-2-fluoroethane and unreacted 1,1,2-trichloroethane; (Ii) at least one step of separation of the compounds from the reaction step to give a first stream comprising hydrochloric acid and a second stream comprising hydrofluoric acid, l-chloro-2,2-difluoroethane, at least one compound (s) and unreacted 1,1,2-trifluoroethane; (Iii) at least one step of separating the second stream to give a PI organic phase comprising l-chloro-2,2-difluoroethane, at least one compound (s) and unreacted 1,1,2-trichloroethane and an inorganic phase P 2 comprising HF; (Iv) at least one step of purifying the organic phase PI obtained in (iii); characterized in that step (iv) comprises:

a) washing the organic phase PI obtained in step (iii) to form an organic phase Bl comprising l-chloro-2,2-difluoroethane, at least one compound (s), 1,1,2-trichloroethane and unreacted 1,1-dichloroethylene; and a non-organic phase

B2 comprising hydrofluoric acid;

b) optionally, drying the organic phase Bl obtained in step a) to form an organic phase B3 comprising l-chloro-2,2-difluoroethane, at least one compound (s), 1,1,2-trichloroethane and unreacted 1,1-dichloroethylene;

c) purification, preferably by distillation, from the organic phase Bl or B3 of the organic phase to form a B4 stream comprising l-chloro-2,2-difluoroethane and 1,1-dichloroethylene; and B5 organic phase comprising the unreacted 1,1,2-trichloroethane and at least one compound (s) A.

11. Method according to the preceding claim characterized in that the washing step a) is performed with water and the non-organic phase is an aqueous phase B2.

12. The method of claim 10 or 11 characterized in that step a) is conducted at a temperature between 0 ° C and 30 ° C at a pressure between 1 and 4 bar abs.