1.1, 1,2,3,3,3-Heptafluoropropane (CF3CHFCF3 or HFC-227ea), a fire extinguishant. can be prepared by the reaction of HF with HFP in contact with activated carbon (e. g., see British Patent Specification No. GB 902,590). The manufacture of HFC-227ea in this instance is tied to the availability HFP.

U. S. Patent No. reports the preparation of 1,1.1.3, 3*3-hexa- fluoropropane (CF3CHCF3 or HFC-236fa), a fire extinguishant and refrigerant, by the reaction of extremely toxic perfluoroisobutylene with triethylamine and water. a refrigerant.

There is a need for alternative methods of manufacturing HFP and other halogenated hydrocarbons containing fluorine, such as the fluorinated propanes HFC-236fa and HFC-236ea.

SUMMARY OF THE INVENTION This invention provides a process for the manufacture of CF3CF=CFo and optionally at least one compound selected from CF3CH2CF3 and CF3CHFCHF2.

The process comprises (a) contacting a reactor feed comprising a precursor stream of at least one compound selected from halogenated propanes of the formula CX3CHCHyX (3. y) and halogenated propenes of the formula CX3CH=CHyX (2 y), where each X is independently selected from Cl and F and y is 0.1 or 2, provided that the average fluorine content of said precursor stream is no more than 5 fluorine substituents per molecule, with HF and CI-) in a chlorofluorination reaction zone containing a fluorination catalyst and operating at a temperature

between about 150°C and 400°C, to produce a reaction zone effluent comprising HF, HCl and a mixture of reaction products of said precursor stream which contains at least one compound of the formula C3C12F6 including CCIF2CCIFCF3 and at least one compound of the formula C3HCIF6 including CHFCCIFCF3 and has an average fluorine content which is at least one fluorine substituent per molecule more than the average fluorine content of the precursor stream; (b) distilling the reaction zone effluent of (a) to produce (i) a low-boiling component comprising HC1 and when they are present in said reaction zone effluent, C3F8, C3C1F7 and C3HF7, (ii) a hydrogenation feed component comprising at least one compound of the formula C3C12F6 including CCIF2CCIFCF3 and at least one compound of the formula C3HC1F6 including CHFCClFCFg, and (iii) an underfluorinated component comprising halogenated propanes containing at least one chlorine substituent and from one to five fluorine substituents; (c) reacting the CC1F2CC1FCF3 and CHF2CClFCF3 of hydrogenation feed component (ii) with hydrogen to produce a mixture comprising CF3CF=CF2 and CF3CHFCHF2; (d) recovering the CF3CF=CF2 from the product mixture of (c); and (e) returning the underfluorinated component (iii) to the chlorofluorination reaction zone.

BRIEF DESCRIPTION OF THE DRAWING Fig. 1 is a schematic flow diagram of an embodiment of the process of this invention.

DETAILED DESCRIPTION The present invention provides a multistep process for the preparation of optionally together with 1,1,1,3, 3, 3-hexafluoro- propane. 1, or mixtures thereof from readily available starting materials.

Suitable precursor stream compounds include the hydrochlorocarbons CCl3CH2CH2Cl, CCl3CH2CHCl2 and CC13CH2CC13. However, in certain embodiments of this invention, the precursor stream compounds of (a) (i. e., halogenated propanes of the formula CX3CH2CHyX (3 y) and halogenated propenes of the formula CX3CH=CHyX(2-y)) can be prepared by reacting one or more of these hydrochlorocarbons (i. e., compounds of the formula CCl3CH2CClZ2, where Z is independently selected from the group consisting of H and Cl) with substantially anhydrous HF in a reaction zone at a temperature of at least 80°C, but not more than about 250°C, to produce a reactor effluent comprising HF. HC1, CF3CH=CZ2, and CF3CH2CZ2F where Z is as defined above. Suitable hydrochlorocarbon reactants for this fluorination include any of CCl3CH2CH ;, CI. CCl3CHCHCl2, and CCl3CH2CCI3. Thus, for example.

CCl3CH2CH2Cl can be reacted with HF to form CF3CH=CH2, and the

fluorination product comprising CF3CH=CH2 can be used as the precursor stream for (a). CC13CH2CHCl2 can be reacted with HF to form CF3CH=CHCI, and the fluorination product comprising CF3CH=CHC1 can be used as the precursor stream for (a). CCl3CH2CCl3 can be reacted with HF to form CF3CH=CC12 and CF3CH2CCI2F and the fluorination product comprising CF3CH=CCl2 and CF3CH2CCI2F can be used as the precursor stream for (a). Of note are embodiments where the reactor effluent from the fluorination, comprising HCI, HF and the CF3CH=CZ2 compound (s), is fed to the chlorofluorination of (a).

The preparation of CCl3CH2CH2Cl is described in U. S. Patent No. The preparation of CCI3CH2CHC12 and CCl3CH2CCl3 is described in International Patent Application No. WO 97/05089.

The fluorination reaction may be carried out in the liquid or vapor phase.

The contacting of CCI3CH2CClZ2 with HF in the liquid phase may be conducted in one of several ways. The process of the invention may be done in batch, semi- continuous. or continuous modes. In the batch mode. liquid CCl3CH2CClZ2 and HF are combined in an autoclave or other suitable reaction vessel and heated to the desired temperature. Preferably, the process of the invention is carried out by feeding liquid CC13CH2CCIZ2 to a reactor containing HF, or a mixture containing HF and fluorinated compounds formed by heating CCl3CH2CCIZ2 and HF.

Alternatively, HF may be fed to a reactor containing CCl3CH2CClZ2, or a mixture of CCl3CH2CClZ2 and of fluorinated compounds formed by reacting HF and CCl3CH2CClZ2. In a variation of this embodiment, both HF and CCl3CHCClZ2 may be fed concurrently in the desired stoichiometric ratio to a reactor containing a mixture of HF and fluorinated compounds formed by reacting HF and CCl3CH2CClZ2.

Preferably, the reaction of HF with CCl3CH2CClZ2 is carried out in the vapor phase in a heated tubular reactor. The reactor may be empty, but is preferably filled with a suitable packing such as Monel or Hastelloy nickel alloy turnings or wool, or other material inert to HCl and HF which allows efficient mixing of liquid CC13CH2CCIZ2 and HF vapor. The CCl3CH2CClZ2 feed rate is determined by the temperature and the degree of fluorination desired.

Suitable temperatures for the fluorination reaction are within the range of from about 80°C to about 250°C, preferably from about 100°C to about 200°C.

Higher temperatures result in greater conversion of the CCl3CH2CClZ2 and a greater degree of fluorination in the converted products. The degree of fluorination reflects the number of fluorine substituents that replace chlorine substituents in the CCl3CH2CClZ2 starting material. For example, the product 3.3,3-trifluoro-1-propene represents a higher degree of fluorination than the product 1,3-dichloro-1,1-difluoropropane.

The pressure used in the fluorination reaction is not critical and in batch reactions is usually the autogenous pressure of the system at the reaction temperature. In a continuous process, typical reactor pressures are from about 20 psig (239 kPa) to about 1,000 psig (6,994 kPa).

In the preferred, vapor phase mode of the fluorination reaction, the reaction may be carried out at atmospheric pressure, or for reasons such as convenience of separations later in the process, pressures of up to 30 atmospheres may be employed.

The mole ratio of HF to CCl3CH2CClZ2 in the fluorination reaction is typically from about 3: 1 to about 75: 1, and is preferably from about 3: 1 to about 50: 1. Ratios of about 8: 1 to about 40: 1 are most preferred as this eliminates the need for further addition of HF in subsequent reaction steps.

Examples of compounds produced in the fluorination reaction include CF3CH=CH2 (HFC-1243zf), CF3CH2CH2F (HFC-254fb), CF3CH=CHCI (HCFC-1233zd), CF3CH2CHClF (HCFC-244fa), CF3CH=CCl2 (HCFC-1223za) and CF3CH2CCI2F (HCFC-234fb).

In addition, small amounts of other halogenated propanes may be formed having greater or lesser degrees of fluorination than the aforementioned products.

Examples of products having a lower degree of fluorination than the aforementioned products include CF3CH2CH2Cl (HCFC-253fb), <BR> <BR> <BR> CClF2CH2CH2Cl (HCFC-252fb), CCl2FCH2CH2Cl (HCFC-251fc),<BR> <BR> <BR> <BR> CCIF2CH=CH2 (HCFC-1242zf), CF3CH2CHC12 (HCFC-243fa), CClF2CH2CHCl2 (HCFC-242fa), CCIF2CH=CHCI (HCFC-1232zd), CClF2CH2CCl2F(HCFC-233fa),CClF2CH2CCl3CF3CH2CCl3(HCFC-233fb) , (HCFC-232fa),CCl2FCH2CCl3(HCFC-231fa)(HCFC-232fb),CCl2FCH2CC l2F and CCI2FCH=CCIF (HCFC-1222zb).

Examples of compounds produced in the fluorination reaction having a higher degree of fluorination than the aforementioned products include CF3CH=CHF (HFC-1234ze), CF3CH2CHF2 (HFC-245fa), CF3CH=CCIF (HCFC-1224zb), CF3CH=CF2 (HFC-1225zc), CF3CH2CCIF2 (HCFC-235fa), and CF3CH2CF3 (HFC-236fa).

A fluorination catalyst is not needed for the reaction of HF with CC13CH2CCIZ2, but may be added if desired to increase the conversion of CCl3CH2CClZ2, the rate of the reaction, or the degree of fluorination of the compounds produced. Liquid phase fluorination catalysts which may be used in the fluorination reaction include carbon, AlF3, BF3, FeCl3 aFa (where a is 0 to 3), FeZ3 (where Z is Cl, F or mixtures thereof) supported on carbon, SbCl3 aFa, AsF3, MCl5-bFb (where b is 0 to 5 and M is Sb, Nb, Ta, or Mo), and M'CI4 cFc (where c is 0 to 4. and M'is Sn, Ti, Zr, or Hf).

Vapor phase fluorination catalysts which may be used in the fluorination reaction include metal compounds (e. g., metal oxides, metal halides, and/or other metal salts). The metal compounds may be unsupported or supported. Suitable supports for the supported catalyst include alumina, aluminum fluoride, fluorided alumina and carbon.

Suitable metal compounds for use as catalysts (optionally on alumina, aluminum fluoride, fluorided alumina, or carbon) include those of chromium, iron, cobalt, nickel, manganese, magnesium, copper and zinc. Preferably when used on a support, the total metal content of the catalyst will be from about 0.1 to 20 percent by weight; typically from about 0.1 to 10 percent by weight.

Of note are chromium-containing catalysts (e. g., Cr203 by itself or with other metal compounds such as magnesium halides or zinc halides on CrOg); and mixtures of chromium-magnesium compounds (including metal oxides, metal halides, and/or other metal salts) optionally on graphite.

Fluorided alumina and aluminum fluoride can be prepared as described in U. S. Patent No. Metal compounds on aluminum fluoride and metal compounds on fluorided alumina can be prepared by procedures described in U. S.

Patent No. 4,766,260. Catalysts comprising chromium are well known in the art (see e. g., U. S. Patent No. 5,036,036). Chromium compounds supported on alumina can be prepared as described in U. S. Patent No. Chromium compounds supported on carbon can be prepared as described in U. S. Patent No. 3,632,834. Catalysts comprising chromium and magnesium compounds may be prepared as described in Canadian Patent No. 2,025,145. Other metal and magnesium compounds optionally on graphite can be prepared in a similar manner to the latter patent.

Preferably. a catalyst is not used in the fluorination reaction. Of particular note are embodiments where CCl3CH2CH2Cl is reacted with HF to form CF3CH=CH2 in a reactor which is free of added catalyst.

The feed to the chlorofluorination reaction zone includes the precursor stream as well as underfluorinated component (iii) from distillation (b).

In (a) of the process of the invention, the precursor stream of at least one compound selected from halogenated propanes of the formula CX3CH2CHyX and halogenated propenes of the formula CX3CH=CHyX (2 y), where each X is independently selected from Cl and F and y is 0,1 or 2, provided that the average fluorine content of said precursor stream is no more than 5 fluorine substituents per molecule, is contacted with HF and chlorine (C12) in a reaction zone for chlorofluorination.

Preferably. the contacting in (a) is carried out in the vapor phase in a heated tubular reactor. Prior to the reactor, a mixing zone. preferably filled with a

suitable packing such as Monel or Hastelloy nickel alloy turnings or wool, or other material inert to HCl and HF, may be employed to allow efficient mixing of HF, HCI, CX3CH2CHyX (3 y), and CX3CH=CHyX (2 y) vapor with chlorine. The flow rates in said tubular reactor in the chlorofluorination reaction zone are determined by the temperature and the degree of fluorination desired. A slower feed rate at a given temperature will increase contact time and tend to increase the amount of conversion of CX3CH2CHyX (3 y), and CX3CH=CH-y) and the amount of fluorine incorporated into the products.

Suitable temperatures for the chlorofluorination are in the range of from about 150°C to about 400°C, preferably from about 200°C to about 325°C.

Higher temperatures result in greater conversion of CX3CH2CHyX (3 y), and CX3CH=CHyX (2 y), and greater degrees of fluorination and chlorination in the converted products. The degree of chlorination reflects the number of chlorine substituents that replace hydrogen substituents in the starting materials. Said chlorine substituents themselves will be replaced by fluorine in the chlorofluorination reaction zone via the reaction of the chlorinated product with HF. For example, the product 1,1,2-trichloro-3,3,3-trifluoropropane (HCFC-233da) represents a higher degree of chlorination than the intermediate 1-chloro-3. 3, 3-trifluoro-1-propene (HCFC-1233zd).

Since the chlorofluorination reaction occurring in (a) is increasing the net number of halogen (i. e.. chlorine and fluorine) substituents in the propane products, it is possible to refer to the degree of halogenation of the products which reflects the total number of chlorine and fluorine substituents that replace hydrogen substituents in the starting material. Thus, the product 2-chloro- 1,1,1,2, 3*3-hexafluoropropane (HCFC-226ba) represents a higher degree of halogenation than the intermediate 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db).

The pressure of the chlorofluorination reaction is not critical and may be in the range of from about 1 to about 30 atmospheres. A pressure of about 20 atmospheres may be advantageously employed to facilitate separation of HCl from other reaction products in (b).

The mole ratio of HF to CX3CH2CHyX (3. y), and/or CX3CH=CHyX (2 y) in the chlorofluorination reaction is typically from about 3: 1 to about 75: 1, and is preferably from about 3: 1 to about 50: 1. Ratios of about 8: 1 to about 40: 1 are most preferred.

The ratio of C12 to CX3CHCHyX (3 y), and/or CX3CH=CHyX (2 y), is typically from about 1: 1 to about 10: 1. The amount of chlorine fed to the chlorofluorination reaction zone in (a) also depends on the hydrogen content of the starting material (s). If y is 0 in the above formulas, a 1: 1 ratio ouf Cl to the

starting material (s) is sufficient for the process of the invention. If y is 2 in the above formulas, then a 3: 1 ratio ouf Cl to the starting material (s) is sufficient for the process of the invention. A slight excess of chlorine over the stoichiometric amount may be necessary for practical reasons, but large excesses of chlorine such as 20: 1 will result in complete chlorofluorination of the products which is not necessary for the process of the invention.

Examples of compounds that may be produced in the chlorofluorination reaction zone (a) include CF3CCIFCHF2 (HCFC-226ba), CF3CHFCC1F2 (HCFC-226ea), CF3CF2CHC1F (HCFC-226ca), CF3CHC1CF3 (HCFC-226da), CF3CCl2CF3 (CFC-216aa), and CF3CC1FCC1F2 (CFC-216ba).

In addition, small amounts of other halogenated propanes may be formed having greater degrees of fluorination. Examples of halogenated propanes having greater degrees of fluorination are CF3CCIFCF3 (CFC-217ba), CF3CF2CC1F2 (CFC-217ca), CF3CHFCF3 (HFC-227ea), CF3CF2CHF2 (HFC-227ca) and CF3CF2CF3 (FC-218).

In addition small amounts of other halogenated propanes may be formed having lower degrees of fluorination and chlorination. Examples of products having lower degrees of fluorination and chlorination include CF3CC12CHF, (HCFC-225aa), CF3CF2CHCl2(HCFC-225ca),(HCFC-225ba), CF3CHClCH2Cl(HCFC-243db),CF3CHClCClF2(HCFC-225da), CF3CCl2CCIF2 (CFC-215aa), CCIFCCIFCCIF (CFC-215ba), CF3CCIFCCI2F (CFC-215bb), CF3CCl2CCl2F (CFC-214ab), CF3CC12CHCIF (HCFC-224aa), CF3CClFCHCl2 (HCFC-224ba), CF3CHCICC12F (HCFC-224db), CF3CCIFCH2CI (HCFC-234bb), CF3CCloCH2Cl (HCFC-233ab), CF3CHClCHCl2 (HCFC-223aa),CF3CHClCCl3CF3CCl2CHCl2 (HCFC-223db) and CF3CCI=CC12 (CFC-1213xa).

Preferably the chlorofluorination reaction of (a) is done in the presence of a fluorination catalyst. Examples of fluorination catalysts suitable for the chlorofluorination in (a) include those described above in connection with CC13CH2CCIZ2 fluorination reactions. Preferred vapor phase fluorination catalysts for (a) comprise trivalent chromium. Of particular note are Cor203 prepared by pyrolysis of (NH4) 2Cr207, Cr203 having a surface area greater than about 200 m2/g, and Cr203 prepared by pyrolysis of (NH4)2Cr2O7 or having a surface area greater than about 200 m2/g which is pre-treated with a vaporizable fluorine-containing compound such as HF or a fluorocarbon such as CC13F.

These pre-treated catalysts are most preferred.

The Cr2O3 catalyst prepared by the pyrolysis of ammonium dichromate suitable for (a) can be prepared by any method known to the art including those disclosed in U. S. Patent Nos. 4,843,181 and 5, 036,036 which are hereby

incorporated herein by reference. Other CrO3 catalysts which may be used in (a) include catalysts having a surface area greater than about 200 m/g, some of which are commercially available.

Generally, the resulting Cr2O3 will be pretreated with HF. This pretreatment can be accomplished by placing Cor203 in a suitable container which can be the reactor to be used to perform the reaction described in (a) in the instant invention, and thereafter, passing HF over the dried Cr2O3 so as to partially saturate the Cr, with HF. This is conveniently carried out by passing HF over the Cr203 for a period of time, for example, about 15 to 300 minutes at a temperature of. for example, about 200°C to about 450°C. Nevertheless, this pretreament is not essential.

In (b) of the process of the invention, the reaction zone effluent from (a) is distilled. Typically, more than one distillation column is employed. The effluent from (a) is delivered to a distillation column to produce a low-boiling component (i) comprising HCI and when they are present in the reaction zone effluent of (a) CF3CF2CF3 (FC-218), CCIF2CF2CF3 (CFC-217ca), CF3CCIFCF3 (CFC-217ba), CHF2CF2CF3 (HFC-227ca) and CF3CHFCF3 (HFC-227ea). Any azeotropes of the above compounds with HCl or HF will also be in the low-boiling component.

It is noted that HFC-227ca and HFC-227ea are themselves valuable as fire extinguishants as disclosed in U. S. Patent No. 5.084,190, and in refrigeration and heat transfer compositions as disclosed in U. S. Patent No. 5,417,871 and in International Application No. WO 95/08603. Accordingly, CFC-217ca and CFC-217ba from the low-boiling component (i) can be reacted with hydrogen after separation to produce additional HFC-227ca and HFC-227ea respectively.

The reaction of hydrogen with CFC-217ca and CFC-217ba is preferably carried out in the vapor phase at a temperature of at least about 100°C and less than 500°C over a metal-containing catalyst at a pressure of from about 100 kPa to about 7,000 kPa. Preferred catalysts for the hydrogenolysis of the C-Cl bonds in CFC-217ca and CFC-217ba include those described for CCIF2CCIFCF3 and CHF2CCIFCF3 hydrogenation herein.

A hydrogenation feed component (ii) is also produced from the distillation process of (b). Components (ii) includes CCIF2CCIFCF3 (CFC-216ba) and CHF2CCIFCF3 (HCFC-226ba). Component (ii) also typically includes HF and one or more of CF3CHFCClF (HCFC-226ea) * CF3CF2CHClF (HCFC-226ca), and CF3CC12CF3 (CFC-216aa). It is normally preferable to adjust the chlorofluorination reaction temperatures such that the production of CF3CCIFCHF and CF3CCIFCCIF2 is maximized. As illustrated in Examples 1 and 2, reaction temperatures above 300°C can greatly increase the amount of CF3CCI-) CF3 and CF3CFCHF, that are formed at the expense of HCFC-226ba

and CFC-216ba. Accordingly, also of note are embodiments where the chlorofluorination of (a) produces CF3CC12CF3, and where the hydrogenation of (c) produces CF3CH2CF3.

A third major fraction produced from the distillation (b) is an underfluorinated component (iii) comprising halogenated propanes containing at least one chlorine substituent and from one to five fluorine substituents.

Examples of compounds in component (iii) include CF3CCl2CHF2 (HCFC-225aa), CF3CCIFCHCIF (HCFC-225ba), CF3CF2C (HCFC-225ca), CF3CHCICCIF2 (HCFC-225da), CF3CHCICH2C1 (HCFC-243db), CF3CC12CCIF2 (CFC-215aa), CClF2CClFCClF2 (CFC-215ba), CF3CCIFCC12F (CFC-215bb), CF3CCl2CCl2F (CFC-214ab), CF3CC12CHC1F (HCFC-224aa), CF3CClFCHCl2 (HCFC-224ba), CF3CHCICC12F (HCFC-224db), CF3CC1FCH2Cl (HCFC-234bb), CF3CCl2CH2Cl (HCFC-233ab), CF3CHC1CHC12 (HCFC-233da), CF3CCI2CHCI2 (HCFC-223aa), CF3CHC1CC13 (HCFC-223db) and CF3CCI=CC12 (CFC-1213xa).

In (c) of the process of the invention, the hydrogenation feed component (ii) removed from the distillation column in (b) is reacted with hydrogen (H-)) in a reaction zone. The hydrogenation feed component (ii) can comprise a mixture of HF, CF3CC1FCHF2 (HCFC-226ba), CF3CHFCC1F2 (HCFC-226ea), CF3CF2CHC1F (HCFC-226ca), CF3CC12CF3 (CFC-216aa), and CF3CC1FCC1F2 (CFC-216ba).

The reaction in (c) is carried out in the vapor phase. Suitable temperatures for the reaction in (c) are in the range of from about 100°C to about 400°C, preferably from about 150°C to about 350°C. Higher temperatures result in greater conversion of CF3CC1FCHF2 (HCFC-226ba), CF3CHFCClF2 (HCFC-226ea), CF3CF2CHClF (HCFC-226ca), CF3CCI2CF3 (CFC-216aa), and CF3CC1FCC1F2 (CFC-216ba).

The pressure used in (c) is not critical and may be in the range of from about 1 to 30 atmospheres. A pressure of about 20 atmospheres may be advantageously employed to facilitate separation of HCI from other reaction products.

The amount of hydrogen (H2) fed to (c) is based on the total amount of CF3CHFCClF2(HCFC-226ea),CF3CF2CHClFCF3CClFCHF2(HCFC-226ba), (HCFC-226ca), CF3CCl2CF3 (CFC-216aa), and CF3CC1FCC1F2 (CFC-216ba) fed to the reaction zone. The ratio of H2 to CF3CC1FCHF2 (HCFC-226ba), CF3CHFCC1F2 (HCFC-226ea), CF3CF2CHCIF (HCFC-226ca), CF3CC12CF3 (CFC-216aa) and CF3CCIFCCIF2 (CFC-216ba) is typically in the range of from about 1: 1 to about 20: 1, preferably from about 2: 1 to about 10: 1.

Compounds produced in the reaction zone in step (c) ordinarily include CF3CF=CF2 (HFP) and CF3CH2CF3 (HFC-236fa). In addition, small amounts of CF3CHFCHF2 (HFC-236ea), CF3CF2CH2F (HFC-236cb) and CF3CHClCF3 (HCFC-226da) will typically be formed.

Preferably the reaction in (c) takes place in the presence of a catalyst.

Suitable catalysts for (c) include iron, rhenium, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, and platinum. Said catalysts are preferably supported on carbon, a metal oxide such as alumina or chromia, fluorided alumina or a metal halide such as AlF3, CrF3 or MgF2. Preparation of carbon-supported palladium catalysts are described in U. S. Patent No. 5,523,501.

Especially preferred catalysts for (c) are those containing rhenium and/or ruthenium. The catalysts containing rhenium and/or ruthenium may or may not be supported. Preferred supports are carbon, alumina, aluminum fluoride and fluorided alumina. Preparation of supported rhenium catalysts are described in U. S. Patent No. Particular ruthenium-containing catalysts are disclosed in PCT International Publication No. WO 97/19751.

In (d) of the process of the invention, CF3CF=CF2 produced in step (c), is recovered. Optionally, CF3CH2CF3 (HFC-236fa), and CF3CHFCHF2 (HFC-236ea) may also be recovered. These compounds are typically recovered by distillation individually or as their HF azeotropes. HF may be removed from these compounds by conventional means such as scrubbing with base or by azeotropic distillation.

In (e) of the process of the invention, the underfluorinated component (iii) of (b) is returned to (a) for further chlorofluorination.

Figure 1 is illustrative of one method of practicing this invention.

Referring to Figure 1, a feed mixture comprising HF and CC13CH-) CCIZ,), where each Z is independently selected from the group H and Cl, and where the mole ratio of HF : CCI3CH2CCIZ2 is about 3: 1 or more, is passed through line (110) into reactor (100). The reaction temperature is at least 80°C but not more than 250°C.

The reactor effluent from fluorination reactor (100) comprising HF, HCI, CF3CH=CZ2, and CF3CH2CZ2F is passed through line (120) into line (420) where it is combined with the column bottoms from distillation column (400).

The column (400) bottoms comprise C3Z3+zF5 z where z is 0,1 or 2. Examples of compounds having the formula C3Z3+zF5-z include CF3CCl2CHF2 (HCFC-225aa), CF3CCIFCHCIF (HCFC-225ba), CF3CF2CHCl2 (HCFC-225ca), CF3CHCICC1F9 (HCFC-225da), CF3CHCICHCl (HCFC-243db), CF3CC12CC1F2 (CFC-215aa), CCIFCCIFCCIF2 (CFC-215ba), CF3CCIFCC12F (CFC-215bb), CF3CCl2CCl2F (HCFC-214ab), CF3CCI2CHCIF (HCFC-224aa), CF3CCIFCHC12 (HCFC-224ba), CF3CHCICC12F (HCFC-224db),

CF3CCl2CH2Cl(HCFC-233ab),CF3CClFCH2Cl(HCFC-234bb), CF3CHC1CHCI2 (HCFC-233da), CF3CCl2CHCl2 (HCFC-223aa) and CF3CHC1CC13 (HCFC-223db).

The combined reactor (100) effluent and distillation column (400) bottoms are sent to reactor (200) which is maintained at a temperature within the range of about 150°C to about 350°C. Reactor (200) is packed with a fluorination catalyst.

A preferred catalyst is Cr203 prepared by the pyrolysis of (NH4) 2Cr907 as described in U. S. Patent No. 5,036,036. Chlorine is fed into the reactor (200) through line (210). The amount of chlorine fed to reactor (200) is based on the amount of CCl3CH2CClX2 fed to reactor (100) and the amount of C3Z3+zF5-z recycled. The mole ratio of Cl2:CCl3CH2CClX2 is within the range of about 1: 1 to about 10: 1. Additional HF may be added, if required.

The chlorofluorination reactor (200) effluent comprising HF, HCI, CF3CCIFCHF2, CF3CHFCCIF2, CF3CClFCClF2, CF3CCI2CF3, and a mixture of C3ZF7 and C3Z3+zF5-z where z is 0,1. or 2. is sent through line (220) into distillation column (300). HCl, C3HF7, C3C1F7, C3F8 and any azeotropes of HC1 or HF with C3HF7, C3CIF7 or C3F8 are removed through line (320) from the reactor (200) effluent and the remaining components of the reactor (200) effluent is sent through line (310) into a second distillation column (400).

HF, CF3CCIFCHF2, CF3CHFCC1F2, CF3CCIFCC1F2, and CF3CC12CF3 are removed from the top of column (400) through line (410) and sent to reactor (500) along with hydrogen, which is fed through line (510). The reactor (500) product is removed through line (520) and comprises, HCl, HF, hexafluoropropylene (i. e., CF3CF=CF2 or HFP), 1,1,1, 3, 3, 3-hexafluoropropane (CF3CH, CF3 or HFC-236fa) and 1 ! 1, 2, 3, 33-hexafluoropropane (HFC-236ea) HFP, HFC-236fa and HFC-236ea can be isolated by conventional means. The bottom fraction from column (400) which comprises C3Z3+zFs z where z is as defined above is sent through line (420) into reactor (200).

Those skilled in the art will recognize that since the drawings are representational, it will be necessary to include further items of equipment in an actual commercial plant, such as pressure and temperature sensors, pressure relief and control valves, compressors, pumps, storage tanks and the like. The provision of such ancillary items of equipment would be in accordance with conventional chemical engineering practice.

The reactors used for this process and their associated feed lines, effluent lines, and other associated units should be constructed of materials resistant to hydrogen fluoride and hydrogen chloride. Typical materials of construction, well- known to the fluorination art, include stainless steels, in particular of the austenitic type. the well-known high nickel alloys, such as MonelT nickel-copper alloys,

alloysand,InconelTMnickel-chromiumalloys,andHastelloyTMnicke l-based copper-clad steel.

Without further elaboration, it is believed that one skilled in the art can, using the description herein, utilize the present invention to its fullest extent. The following embodiments are. therefore, to be construed as merely illustrative, and do not constrain the remainder of the disclosure in any way whatsoever.

EXAMPLES LEGEND 114a is CCl2FCF3 115 is CCIF2CF3 214ab is isCClF2CCl2CF3215aa 215ba is CClF2CClFCClF2 215bb is CC12FCCIFCF3 216aa is isCClF2CClFCF3216ba 216ca is CClF2CF2CClF2 216cb is CF3CF2CC12F 217ba is CF3CC1FCF3 217ca is CCIF2CF2CF3 218 is isCF3CCl2CHCl2223aa 224aa is CF3CCI2CHCIF 224ba is CF3CC1FCHCI2 225aa is CHF2Cl2CF3 225ba is CHCIFCCIFCF3 225ca is CHCl2CF2CF3 226ba is CF3CCIFCHF2 226ca is CF3CF2CHCIF 226da is CF3CHCICF3 226ea is CCIF2CHFCF3 227ca is CF3CF2CHF2 227ea is CF3CHFCF3 232 is C3H2C14F2 233ab is CF3CCl2CH2Cl 233da is CF3CHC1CHCI2 234 is C3H2C12F4 234bb is CF3CC1FCH2C1 234da is CF3CHClCHClF 235cb is CF3CF2CH2CI 235da is CF3CHClCHF2 236fa is CF3CH2CF3 242 is C3H3C13F2 243db is CF3CHClCH2Cl 244 is C3H3C1F4 245fa is CF3CH2CHF2 252 is C3H4Cl2F2 1213xa is CC12=CCICF3 C3Cl2F41215isC3ClF51214is 1222 is C3HC13F2 1223 is C3HC12F 1224 is C3HC1F4 1231 is C3H2Cl3F 1232 is isCH2=CClCF31233xf 1233zd is CHC1=CHCF3 1234 is C3H2F4 1234ye is CHF=CFCHF2 1234ze is CHF=CHCF3 1243 is C3H3F3 1243zf is CH2=CHCF3 CT is contact time General Procedure for Product Analysis The following general procedure is illustrative of the method used. Part of the total reactor effluent was sampled on-line for organic product analysis using a

Hewlett Packard HP 5890 gas chromatograph equipped with a 20 ft. (6.1 m) long x 1/8 in. (0.32 cm) diameter tubing containing KrytoxO perfluorinated polyether on an inert carbon support. The helium flow was 30 mL/min. Gas chromatographic conditions were 60°C for an initial hold period of three minutes followed by temperature programming to 200°C at a rate of 6°C/minute.

The bulk of the reactor effluent containing organic products and also inorganic acids such as HC1 and HF was treated with aqueous caustic prior to disposal.

EXAMPLE 1 Chlorofluorination of CCl3CH9CH9Cl Chromium oxide (40.0 g, 30 mL,-12 to +20 mesh, (1.68 to 0.84 mm)), obtained from the pyrolysis of ammonium dichromate prepared according to the procedure described in U. S. Patent No. 5,036,036, was placed in a 5/8" (1.58 cm) diameter Inconel nickel alloy reactor tube heated in a fluidized sand bath. The catalyst was heated from 60°C to 175°C in a flow of nitrogen (50 cc/min) over the course of about one hour. HF was then admitted to the reactor at a flow rate of 50 cc/min. After 35 minutes, the nitrogen flow was decreased to 20 cc/min and the HF flow increased to 80 cc/min. The reactor temperature was gradually increased to 400°C during a three hour period and maintained at 400°C for an additional 55 minutes. At the end of this period, the HF flow was stopped and the reactor cooled to 250°C under 20 sccm (3. 3 x 10-7 m3/s) nitrogen flow.

The results of the chlorofluorination of CCl3CH2CH2Cl are shown in Table 1 ; analytical data is given in units of GC area%. Total gas flow in the <BR> reactor was 120 sccm (2.0 x 10-6 m3/s) for a 15 second contact time except for the data at 400°C which was conducted with a 30 second contact time.

TABLE 1 T Molar Ratio C. T. % % % % % % % °C HF: 250fb : Clg Sec. 1243zf 242 243db 244** 234bb 224aa 224ba 170 20: 1: 0 nc 97.5 0 0 0.1 0 0 0 200 30: 1: 6 nc 35.4 4.2 34.9 2.6 0 0 0 200 30: 1: 6 15 0. 1 0 55.3 7.1 6.7* 4.2 0 225 30: 1: 6 15 0 0 10.6 3. 1 19.0 20.0 0 250 30: 1: 6 15 0 0 0 0 0.8 31.7 25.3 275 30: 1: 6 15 0 0 0 0 0 3.1 4.6 300 30: 1: 6 15 0 0 0 0 0 0.5 0.7 325 30: 1: 6 15 0 0 0 0 0 0.3 0. 3 350 30: 1: 6 15 0 0 0 0 0 0 0 375 30: 1: 6 15 0 0 0 0 0 0 0 400 30: 1: 6 30 0 0 0 0 0 0 0 nc = no catalyst; reactants mixed in tube packed with Monel gauze (not exposed to the fluorination catalyst) *Includes 1.7% of unidentified isomer **Sum of three isomers TABLE 1. contd.

T % % % % % % % % % °C 1233zd 1233xf 233ab 223aa 1213xa 1214* 215aa** 225aa 225ba 170 0 0 0 0 0 0 0 0 0 200 4.6 4.0 3.2 2.5 0 0 0 0 0 200 5.8 1.5 10.7 0.5 2.4 0 0 0.1 0 225 1.3 0.4 32.0 2.1 6.8 0 0 0.4 0.5 250 0.1 0.1 0.3 0 6.5 4.3 2.8 7.1 18.8 275 0 0 0 0 0.5 0.2 7.0 37.3 18.7 300 0 0 0 0 0.1 0 7.4 26.3). 3 325 0 0 0 0 0.1 0 8.9 5.2 1.2 350 0 0 0 0 0 0 0.8 1. 1 0.2 375 0 0 0 0 0 0 0.9 0.6 0.2 400 0 0 0 0 0 0 0. 2 0.2 0 *sum of two isomers **includes <1% of an unidentified isomer

TABLE 1. contd.

T % % % % % % % % % oc 225ca 226ba 226ca 216ba 216aa 217ba 217ca 227ca 218 000000001700 200 0 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 0 0 225 0 0 0 0 0 0 0 0 0 <BR> <BR> <BR> <BR> 250 0 0.6 0 0. 1 0.2 0 0 0 0<BR> <BR> <BR> <BR> <BR> <BR> 275 4.2 14.7 4.4 1.7 1.2 0.1 0 0.4 0 300 3.4 31.2 7.7 2.4 4. 4 0.5 1.1 9.0 0 325 3.3 24.3 5.3 3.8 16.1 1. 1 3.8 24.5 0 350 0.9 10.7 3.4 3. 2 25.2 6.1 7.4 39. 4 0. 4 375 1.6 2.1 3.3 2.9 45.5 7.6 12.9 19.9 1.2 400 0.4 0.9 1.3 0. 8 59.4 15.0 6. 4 9.7 4.7 Other compounds observed at low levels include: 216cb, 226da. 232,235cb. 245fa, 252.1222,1223, 1232,1234ye, 1234ze.

EXAMPLE 2 Chlorofluorination of CClCHCHCb A fresh charge of chromium oxide (40.0 g, 30 mL,-12 to +20 mesh, (1.68 to 0.84 mm)) was loaded in the reactor and activated with HF following the procedure described in Example 1.

The results of the chlorofluorination of CCl3CH2CHCl2 are shown in Table 2 ; analytical data is given in units of GC area %. Total gas flow in the reactor was 120 sccm (2.0 x 10-6 m3/s) for a 15 second contact time except for the data at 400°C which was conducted with a 30 second contact time.

TABLE 2 T Molar Ratio C. T. % % % °/0 % % % °C HF: 240fa: CIn Sec. 1234* 1243 242 244 234da* 224aa 224ba 200 20: 1: 0 nc 2.7 0.1 0.2 0.3 0 0 0 200 30: 1: 6 nc 4.5 0 4.2 2.6 1.4 0 0 225 30: 1: 6 15 0 0 0 0 0 47.4 22.0 250 30: 1: 6 15 0 0 0 0 0 21. 1 23.8 275 30: 1: 6 15 0 0 0 0 0 1.6 2.6 300 30: 1: 6 15 0 0 0 0 0 0.4 0.6 325 30: 1: 6 15 0 0 0 0 0 0.2 0.3 350 30: 1: 6 15 0 0 0 0 0 0.06 0.09 375 30: 1: 6 15 0 0 0 0 0 0 0 400 30: 1: 6 30 0 0 0 0 0 0 0 nc = no catalyst; reactants mixed in tube packed with Monel gauze (not exposed to the fluorination catalyst) *sum of two isomers TABLE 2. contd.

T % % % % % % % % °C 1223* 1233zd* 233da 223aa 1224* 235da 1213xa 1214 200 0 96.6 0 0 0 0 0 0 200 6.6 77.0 8.0 0 0 0 0 0 225 1.8 0 0 4.5 0.95 13.0 0.3 0 250 0 0 0 0.7 1.0 2.0 0 1. 3 275 0 0 0 0 0.1 0 0 0 300 0 0 0 0 0.2 0 0 0 325 0 0 0 0 0 0 0 0 350 0 0 0 0 0 0 0 0 375 0 0 0 0 0 0 0 0 400 0 0 0 0 0 0 0 0 *sum of two isomers TABLE 2, contd.

T % % % % % % % % °C 214ab 215ba/bb 215aa 225aa 225ba* 225ca 216ca/cb 226da 200 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 0 225 0.3 0.3 0.9 4.6 2.6 0 0 0 250 0 1.0 2.8 14.8 28.7 0 0 0 275 0 0.2 6.0 42.3 13.8 3.8 0.5 0. 3 300 0 0 6.8 24.4 3.2 2.4 0.6 0.6 325 0 0 8.4 5.1 1. 1 2.2 0.5 0.5 350 0 0 2.0 1.4 0.4 1.7 0.4 0.1 375 0 0 0.02 0.08 0 0 0.1 0.03 400 0 0 0.2 0 0 0.06 0. 2 0 *sum of two isomers TABLE 2, contd.

T % % % % % % % % °C 226ba 226ca 216ba 216aa 217ba 217ca 227ca 218 200 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 0 225 0 0 0 0 0 0 0 0 250 1.4 0.09 0.4 0.3 0 0 0 0 275 17.9 5.9 2.2 1.5 0.1 0.08 0.7 0 300 33.8 6.7 2.7 5.1 0.4 1.2 10. 3 0 325 26. 1 4.8 4. 1 16.6 0.97 3.9 24.7 0.04 350 7.8 4.3 4.4 32.5 3.5 8.5 32.1 0.3 375 5.4 0.5 2.2 35.1 11.6 9.6 32.6 1.8 400 0.2 0. 2 0.8 6.2 Other compounds observed at low levels include: 114a, 115,236fa, 1215, 1231