PROCESS OF CHLORINATING HYDROCHLOROFLUOROOLEFIN TO PRODUCE CHLOROFLUOROOLEFIN BACKGROUND

Field of the Disclosure

This disclosure relates in general to the chlorination reactions of hydrochlorofluoroolefins to produce chlorofluoroolefins.

Description of Related Art

CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons) have been employed in a wide range of applications, including their use as aerosol propellants, refrigerants, cleaning agents, expansion agents for thermoplastic and thermoset foams, heat transfer media, gaseous dielectrics, fire extinguishing and suppression agents, power cycle working fluids, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, and displacement drying agents. Due to the belief that CFCs and HCFCs are contributing to depletion of stratospheric ozone, there has been extensive work in the past two decades on replacement of these materials with non-ozone depleting substances. Hydrofluorocarbons (HFCs), which do not contain chlorine, have replaced CFCs and HCFCs in a number of applications. Although HFCs do not contribute to the destruction of stratospheric ozone, they are of concern due to their potential contribution to the "greenhouse effect" (global warming). Thus, there is a need for compositions in the applications noted above that do not contribute to the destruction of stratospheric ozone and also have low global warming potentials (GWPs). Certain

hydrofluoroolefins, such as CF ₃ CH=CHCF ₃ , are believed to meet both goals, and chlorofluoroolefins, such as CF ₃ CCI=CCICF ₃ , are intermediates in the production of these hydrofluoroolefins.

BRIEF SUMMARY OF THE DISCLOSURE

The present disclosure provides a process for the preparation of chlorofluoroolefin. The process comprises chlorinating a

hydrochlorofluoroolefin of the formula R ¹ CH=CCIR ² to produce a product mixture comprising a chlorofluoroolefin of the formula R ¹ CCI=CCIR ² ;

wherein R ¹ and R ² are perfluoroalkyl groups independently selected from the group consisting of CF ₃ , C ₂ F ₅ , n-C ₃ F ₇ , i-C ₃ F ₇ , n-C ₄ F ₉ , i-C ₄ F ₉ and t-

DETAILED DESCRIPTION

CF ₃ CH=CCICF ₃ (2-chloro-1 ,1 ,1 ,4,4,4-hexafluorobutene-2, HCFO- 1326mxz) can be a major impurity in a hydrogenating process of

CF ₃ CCI=CCICF ₃ to produce CF ₃ CH=CHCF ₃ . Thus, there is a need to convert CF ₃ CH=CCICF ₃ to CF ₃ CCI=CCICF ₃ which can be recycled for the production of CF ₃ CH=CHCF ₃ .

The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as defined in the appended claims. Other features and benefits of any one or more of the embodiments will be apparent from the following detailed description, and from the claims.

As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, "or" refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

Also, use of "a" or "an" are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention, suitable methods and materials are described below. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

When an amount, concentration, or other value or parameter is given as either a range, preferred range or a list of upper preferable values and/or lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range.

The term "an elevated temperature", as used herein, means a temperature higher than the room temperature.

Disclosed is a process for the preparation of chlorofluoroolefin comprising chlorinating a hydrochlorofluoroolefin of the formula

R ¹ CH=CCIR ² to produce a product mixture comprising a chlorofluoroolefin of the formula R ¹ CCI=CCIR ² ; wherein R ¹ and R ² are perfluoroalkyl groups independently selected from the group consisting of CF ₃ , C2F ₅ , n-C3F ₇ , i- C ₃ F ₇ , n-C ₄ F ₉ , i-C ₄ F ₉ and t-C ₄ F ₉ .

More specifically, a chlorinating process for the preparation of chlorofluoroolefin is disclosed. The chlorinating process comprises contacting a hydrochlorofluoroolefin of the formula R ¹ CH=CCIR ² with chlorine in a reaction zone at a temperature of from about 290°C to about 360°C to produce a product mixture comprising a chlorofluoroolefin of the formula R ¹ CCI=CCIR ² ; wherein R ¹ and R ² are perfluoroalkyl groups independently selected from the group consisting of CF ₃ , C2F ₅ , n-CsF ₇ , i- C ₃ F ₇ , n-C ₄ F ₉ , i-C ₄ F ₉ and t-C ₄ F ₉ . In some embodiments of this invention, the hydrochlorofluoroolefin starting material is CF ₃ CH=CCICF ₃ (i.e., R ¹ = R ² = CF ₃ ) and the

chlorofluoroolefin product is CF ₃ CCI=CCICF ₃ .

Hydrochlorofluoroolefins and chlorofluoroolefins in this disclosure exist as different configurational isomers or stereoisomers. When the specific isomer is not designated, the present disclosure is intended to include all configurational isomers, stereoisomers, or any combination thereof. For instance, CF ₃ CH=CCICF ₃ is meant to represent the E-isomer, Z-isomer, or any combination or mixture of both isomers in any ratio.

In some embodiments of this invention, the chlorinating process is carried out in the absence of a free-radical initiator. In some embodiments of this invention, the chlorinating process is carried out in the absence of a catalyst. In some embodiments of this invention, the chlorinating process is thermal chlorination carried out at an elevated temperature in the absence of an ultraviolet light.

The chlorinating process of this disclosure can be carried out by contacting the hydrochlorofluoroolefin of the formula R ¹ CH=CCIR ² with chlorine (CI2) in a reaction zone to produce a product mixture comprising the chlorofluoroolefin of the formula R ¹ CCI=CCIR ² . The reaction zone temperature typically ranges from about 290° C to about 360° C. The reaction zone temperature can be about 290°C, 291 °C, 292°C, 293°C, 294°C, 295°C, 296°C, 297°C, 298°C, 299°C, 300°C, 301 °C, 302°C, 303°C, 304°C, 305°C, 306°C, 307°C, 308°C, 309°C, 310°C, 31 1 °C, 312°C, 313°C, 314°C, 315°C, 316°C, 317°C, 318°C, 319°C, 320°C, 321 °C, 322°C, 323°C, 324°C, 325°C, 326°C, 327°C, 328°C, 329°C, 330°C, 331 °C, 332°C, 333°C, 334°C, 335°C, 336°C, 337°C, 338°C, 339°C, 340°C, 341 °C, 342°C, 343°C, 344°C, 345°C, 346°C, 347°C, 348°C, 349°C, 350°C, 351 °C, 352°C, 353°C, 345°C, 355°C, 356°C, 357°C, 358°C, 359°C, or 360°C. In some embodiments of this invention, the reaction zone temperature ranges from about 300°C to about 325°C. In some embodiments of this invention, the reaction zone temperature ranges from about 310°C to about 320°C. A lower temperature

chlorinating reaction may generate a considerable amount of the byproduct R ¹ CCl ₂ CCl ₂ R ² . On the other hand, a higher temperature chlorinating reaction may generate a considerable amount of the byproduct R ¹ CCI ₃ and R ² CCI ₃ .

The molar ratio of chlorine to hydrochlorofluoroolefin of the formula R ¹ CH=CCIR ² fed to the reaction zone is typically from about 1 :1 to about 1.5:1. The molar ratio can be about 1.0:1.0, 1.01 :1.0, 1.02:1.0, 1.03:1.0, 1.04:1.0, 1.05:1.0, 1.06:1.0, 1.07:1.0, 1.08:1.0, 1.09:1.0, 1.10:1.0,

1.11:1.0, 1.12:1.0, 1.13:1.0, 1.14:1.0, 1.15:1.0, 1.16:1.0, 1.17:1.0,

1.18:1.0, 1.19:1.0, 1.20:1.0, 1.21:1.0, 1.22:1.0, 1.23:1.0, 1.24:1.0,

1.25:1.0, 1.26:1.0, 1.27:1.0, 1.28:1.0, 1.29:1.0, 1.30:1.0, 1.31 :1.0,

1.32:1.0, 1.33:1.0, 1.34:1.0, 1.35:1.0, 1.36:1.0, 1.37:1.0, 1.38:1.0,

1.39:1.0, 1.40:1.0, 1.41:1.0, 1.42:1.0, 1.43:1.0, 1.44:1.0, 1.45:1.0,

1.46:1.0, 1.47:1.0, 1.48:1.0, 1.49:1.0, or 1.50:1.0. In some embodiments of this invention, the molar ratio of chlorine to hydrochlorofluoroolefin of the formula R ¹ CH=CCIR ² fed to the reaction zone is from about 1 :1 to about 1.3:1. In some embodiments of this invention, the molar ratio is from about 1 :1 to about 1.2:1. In some embodiments of this invention, the molar ratio is from about 1 :1 to about 1.1:1.

The chlorinating process of this disclosure can be carried out either in a liquid phase or in a gas phase using well-known chemical engineering practice, which includes continuous, semi-continuous or batch operations. In some embodiments of this invention, the chlorinating process is carried out in the absence of a solvent or a diluent.

In some embodiments of this invention, the chlorinating process may be carried out in the liquid phase by feeding CI ₂ to a reactor containing hydrochlorofluoroolefin of the formula R ¹ CH=CCIR ² . In some embodiments of this invention, the temperature and the pressure are properly controlled and the reactor is equipped with a condenser or other means to keep the starting materials (R ¹ CH=CCIR ² and CI ₂ ) and the desired product (chlorofluoroolefin of the formula R ¹ CCI=CCIR ² ) in the liquid state while permitting the hydrogen chloride (HCI) released during the chlorination to escape the reactor.

In some embodiments of this invention, the chlorinating process may be carried out in a gas phase. The reactor for carrying out the gas phase chlorinating process may be of any shape consistent with the process but is preferably a cylindrical tube, either straight or coiled. In some embodiments of this invention, the gas phase reactor is substantially empty. Substantially empty reactors include those wherein the flow of gases through the reactor is partially obstructed to cause back-mixing, i.e. turbulence, and thereby promote mixing of gases and good heat transfer. This partial obstruction can be conveniently obtained by placing packing within the interior of the reactor, filling its cross-section or by using perforated baffles. The reactor packing can be particulate or fibrillar, preferably in cartridge disposition for ease of insertion and removal, has an open structure like that of Raschig Rings or other packings with a high free volume, to avoid the accumulation of coke and to minimize pressure drop, and permits the free flow of gas. The free volume of the reaction zone is at least about 80%. In some embodiments of this invention, the free volume of the reaction zone is at least about 90%. In some embodiments of this invention, the free volume of the reaction zone is at least about 95%. The free volume is the volume of the reaction zone minus the volume of the material that makes up the reactor packing.

The chlorinating process of this disclosure can be carried out in batch reactors, continuous reactors or any combination of such reactors by methods known in the art. In some embodiments of this invention, the starting materials (R ¹ CH=CCIR ² and CI2) are co-fed to a reactor. In some embodiments of this invention, CI2 is fed to a reactor containing

hydrochlorofluoroolefin of the formula R ¹ CH=CCIR ² .

The effluent from the chlorination reaction zone is typically a product mixture comprising unreacted starting materials (R ¹ CH=CCIR ² and chlorine), the desired chlorofluoroolefin product of the formula

R ¹ CCI=CCIR ² , HCI, and some byproducts.

The reactors, packings, distillation columns, and their associated feed lines, effluent lines, and associated units used in applying the processes of embodiments of this invention may be constructed of materials resistant to corrosion. Typical materials of construction include TeflonTM and glass. Typical materials of construction also include stainless steels, in particular of the austenitic type, the well-known high nickel alloys, such as MonelTM nickel-copper alloys, HastelloyTM nickel- based alloys and, InconelTM nickel-chromium alloys, and copper-clad steel.

Many aspects and embodiments have been described above and are merely exemplary and not limiting. After reading this specification, skilled artisans appreciate that other aspects and embodiments are possible without departing from the scope of the invention.

EXAMPLES

The concepts described herein will be further described in the following examples, which do not limit the scope of the invention described in the claims.

LEGEND

Example 1

Example 1 demonstrates the chlorination of 2-chloro-1 ,1 ,1 ,4,4,4- hexafluorobutene-2 to form 2,3-dichloro-1 ,1 ,1 ,4,4,4-hexafluorobutene-2.

A 210 ml Hastelloy® shaker tube was loaded with 17g (0.085 mole) of trans-2-chloro-1 ,1 ,1 ,4,4,4-hexafluorobutene-2 (98 mole % purity). The shaker tube was cooled down in dry-ice and evacuated. To the tube, 6.6g (0.09 mole) of Cl ₂ was added. The Cl ₂ : trans-CF ₃ CH=CCICF ₃ molar ratio was therefore 1 .06:1 (0.09/0.085). Subsequently, the shaker tube was heated to 300° C and was shaken for 5 hrs. In the next step, the shaker tube was cooled down to room temperature. A 10% NaHSO ₃ aqueous solution was injected to the tube. The tube was unloaded and 13g of lower layer was separated and analyzed by Gas Chromatography/Mass Spectrometry (GC/MS). It was found that the mixture contained 1 .9 mole % t-1326; 2.4 mole % c-1326; 0.35 mole % 123; 0.9 mole % 1 13a; 45.0 mole % t-1316; 40.1 mole % c-1316; 0.7 mole % 326 mda; and 8.3 mole % 316 maa.

Example 2 (Comparative)

Example 2 demonstrates that at 100° C the chlorination of 2-chloro- 1 ,1 ,1 ,4,4,4-hexafluorobutene-2 does not form 2,3-dichloro-1 ,1 ,1 ,4,4,4- hexafluorobutene-2.

A 210 ml Hastelloy® shaker tube was loaded with 17g (0.085 mole) of trans-2-chloro-1 ,1 ,1 ,4,4,4-hexafluorobutene-2 (98 mole % purity). The shaker tube was cooled down in dry-ice and evacuated. To the tube, 6.6g (0.09 mole) of C\ ₂ was added. The C\ ₂ : trans-CF ₃ CH=CCICF ₃ molar ratio was therefore 1 .06:1 (0.09/0.085). Subsequently, the shaker tube was heated to 100° C and was shaken for 3 hrs. In the next step, the shaker tube was cooled down to room temperature. A 10% NaHSO3 aqueous solution was injected to the tube. The tube was unloaded and 13g of lower layer was separated and analyzed by GC/MS. It was found that the mixture contained 85.1 mole % t-1326; 1 .9 mole % c-1326; and 12.9 mole % 326 mda.

Example 3 (Comparative)

Example 3 demonstrates that at 280° C the chlorination of 2-chloro-

1 ,1 ,1 ,4,4,4-hexafluorobutene-2 forms mostly 316 maa.

A 210 ml Hastelloy® shaker tube was loaded with 12g (0.06 mole) of trans-2-chloro-1 ,1 ,1 ,4,4,4-hexafluorobutene-2 (98 mole % purity). The shaker tube was cooled down in dry-ice and evacuated. To the tube, 5.1 g (0.073 mole) of Cl ₂ was added. The Cl ₂ : trans-CF ₃ CH=CCICF ₃ molar ratio was therefore 1 .2:1 (0.073/0.06). Subsequently, the shaker tube was heated to 280° C and was shaken for 5 hrs. In the next step, the shaker tube was cooled down to room temperature. A 10% NaHSO3 aqueous solution was injected to the tube. The tube was unloaded and 10g of white solid was isolated and analyzed by GC/MS. It was found that the mixture contained 3.2 mole % 1 13a; 0.2 mole % t-1316; 0.4 mole % c- 1316; and 96.1 mole % 316 maa. Example 4

Example 4 demonstrates the chlorination of 2-chloro-1 ,1 ,1 ,4,4,4- hexafluorobutene-2 to form 2,3-dichloro-1 ,1 ,1 ,4,4,4-hexafluorobutene-2.

A 210 ml Hastelloy® shaker tube was loaded with 17g (0.085 mole) of trans-2-chloro-1 ,1 ,1 ,4,4,4-hexafluorobutene-2 (98 mole % purity). The shaker tube was cooled down in dry-ice and evacuated. To the tube, 7g (0.1 mole) of Cl ₂ was added. The C\ ₂ : trans-CF ₃ CH=CCICF ₃ molar ratio was therefore 1 .18:1 (0.1/0.085). Subsequently, the shaker tube was heated to 350° C and was shaken for 5 hrs. In the next step, the shaker tube was cooled down to room temperature. A 10% NaHSO3 aqueous solution was injected to the tube. The tube was unloaded and 17g of lower layer was separated and analyzed by GC/MS. It was found that the mixture contained 3.5 mole % t-1326; 0.1 mole % c-1326; 0.86 mole % 123; 1 1 mole % 1 13a; 43.5 mole % t-1316; and 38.5 mole % c-1316. Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed are not necessarily the order in which they are performed.

In the foregoing specification, the concepts have been described with reference to specific embodiments. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification is to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of invention.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

It is to be appreciated that certain features are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination.