HK1098981A - Chromium oxide compositions containing zinc, their preparation, and their use as catalysts and catalyst precursors - Google Patents

Description

Zinc-containing chromium oxide compositions, their preparation and their use as catalysts and catalyst precursors

Technical Field

The present invention relates to chromium-containing compositions, their preparation, and their use in hydrocarbon and/or halogenated hydrocarbon catalytic processes.

Background

U.S. Pat. No. 5,281,568 discloses a fluorination catalyst containing chromium and zinc. The amount of zinc can range from about 0.5% by weight to about 25% by weight.

Australian patent document No. AU-a-80340/94 discloses bulk or supported catalysts based on chromium omutexide (or chromium omutexide) and at least one other catalytically active metal (e.g. Mg, V, Mn, Fe, Co, Ni or Zn), wherein the majority of the omutexide is in crystalline form (and when the catalyst is a bulk catalyst its specific surface is at least 8m after activation with HF²In terms of/g). The disclosed crystalline phase comprises Cr₂O₃、CrO₂、NiCrO₃、NiCrO₄、NiCr₂O₄、MgCrO₄、ZnCr₂O₄And mixtures of these oxides.

U.S. Pat. No. 3,878,257 discloses the catalytic reaction of 1, 1, 2-trichlorotrifluoropropene with hydrogen fluoride in the presence of a catalyst combination that activates anhydrous chromium (III) oxide and a divalent zinc compound to produce 2-chloropentafluoropropene.

There is also a need for catalysts useful in processes such as the selective fluorination and chlorofluorination of saturated and unsaturated hydrocarbons, chlorinated hydrocarbons, fluorochlorohydrocarbons and chlorofluorocarbons (chlorofluorocarbons), fluorination of unsaturated fluorine-containing hydrocarbons (fluorohydrocarbons), isomerization and disproportionation of fluorinated organic compounds, dehydrofluorination of fluorinated hydrocarbons, and chlorodefluorination of fluorine-containing hydrocarbons (chlorodefluorination).

Summary of The Invention

The invention provides a composition comprising ZnCr₂O₄Chromium-containing catalyst composition of (zinc chromite) and crystalline alpha-chromium oxide, wherein ZnCr is present in the composition₂O₄Containing from about 10 to 67 at% chromium and containing at least about 70 at% zinc, and wherein at least about 90 at% of the chromium present as chromium oxide in the composition is ZnCr₂O₄Or crystalline alpha-chromium oxide.

The invention also provides a composition comprising ZnCr₂O₄And a process for preparing said composition of crystalline alpha-chromium oxide. The process comprises (a) coprecipitating a solid by adding ammonium hydroxide (ammonia) to an aqueous solution of a soluble zinc salt and a soluble trivalent chromium salt, wherein each mole of chromium (i.e., Cr) in said solution is³⁺) Containing at least 3 moles of nitrate (i.e. NO)^3-) And the concentration of zinc in said solution is from about 5 mole% to about 25 mole% of the total concentration of zinc and chromium, and wherein the concentration of zinc in said solution is about 5 mole% to about 25 mole% per mole of chromium (i.e., Cr)³⁺) At least 3 moles of ammonium (i.e., NH)₄ ⁺) Has been added to the solution, (b) the solid formed by coprecipitation in (a) is collected; (c) drying the collected solid; and (d) calcining the dried solid.

The invention also provides chromium-containing catalyst compositions prepared by treating ZnCr-containing catalysts with fluorinating agents (e.g., anhydrous hydrogen fluoride)₂O₄And crystalline alpha-chromium oxide.

The present invention also provides for altering the fluorine distribution in a halogenated hydrocarbon in the presence of a catalyst (i.e., altering the fluorine distribution in the halogenated hydrocarbonContent and/or arrangement) or introducing fluorine into a saturated or unsaturated hydrocarbon. The process is characterized in that at least one composition selected from (i) the ZnCr compositions of the invention is used as catalyst₂O₄And crystalline alpha-chromium oxide compositions and (ii) ZnCr of the present invention which has been treated with a fluorinating agent₂O₄And crystalline alpha-chromium oxide compositions.

Brief description of the drawings

FIG. 1 shows the energy dispersion spectrum (energy dispersiVe spectroscopy) of the zinc chromite phase present in a zinc/chromium oxide composition nominally containing 20 atomic% zinc.

FIG. 2 shows the presence of alpha-Cr in the same zinc/chromium oxide composition nominally containing 20 atomic% zinc₂O₃Energy dispersion spectrum of the phase.

Detailed Description

The composition of the invention is a composition comprising ZnCr₂O₄And zinc and chromium containing oxides of crystalline alpha-chromium oxide, wherein ZnCr is present in the composition₂O₄Containing from about 10 to 67 at% chromium and at least about 70 at% zinc. The disclosed composition includes a composition comprising ZnCr₂O₄And crystalline alpha-chromium oxide.

The compositions of the present invention may be prepared by the above-described method using co-precipitation followed by calcination. These methods include, but are not limited to, precipitation from aqueous solutions containing chromium and zinc salts in the desired molar ratio.

In a typical co-precipitation technique, an aqueous solution of zinc and chromium (III) salts is prepared. The relative concentrations of zinc and chromium (III) salts in the aqueous solution are determined by the bulk atomic percent of zinc to chromium (the bulk atom percent) in the final catalyst. In thatThe zinc concentration in the solution is from about 5 mole percent to about 25 mole percent of the total concentration of zinc and chromium. The chromium (III) concentration in the aqueous solution is typically in the range of 0.3-3 moles/liter, with 0.75-1.5 moles/liter being the preferred concentration. Although different chromium (III) salts may be used, for the preparation of the aqueous solution chromium (III) nitrate or hydrates thereof such as [ Cr (NO)₃)₃(H₂O)₉]The most preferred chromium (III) salts.

For the preparation of the aqueous solution, although different zinc salts may be used, for the catalyst preparation of the process of the present invention, preferred zinc salts include zinc (II) nitrate and hydrates thereof such as [ Zn (NO) ]₃)₂(H₂O)₆]。

The aqueous solution of chromium (III) and zinc salt may then be evaporated in vacuo or at elevated temperature to give a solid which is then calcined.

The aqueous solution of chromium (III) and zinc salts is preferably treated with a base such as ammonium hydroxide (ammonia) to precipitate the zinc and chromium as hydroxides. Alkali metal-containing bases such as sodium hydroxide or potassium hydroxide or their carbonates may be used, but they are not preferred. Typically, ammonium hydroxide is added gradually over a period of 1-12 hours to the aqueous solution of chromium (III) and zinc salt. The pH of the solution was monitored during the addition of the base. The final pH is typically in the range of 6.0 to 11.0, preferably in the range of about 7.5 to about 9.0, most preferably in the range of about 8.0 to 8.7. The precipitation of the zinc and chromium hydroxide mixture is typically carried out at a temperature of from about 15 ℃ to about 60 ℃, preferably from about 20 ℃ to about 40 ℃. After the ammonium hydroxide is added, the mixture is typically stirred for up to 24 hours. Precipitated hydroxides of chromium and zinc as ZnCr₂O₄And precursors of crystalline alpha-chromium oxide.

After the precipitation of the zinc and chromium hydroxide mixture was complete, the mixture was dried. Drying can be carried out by evaporation at a suitable temperature in an open pan on a hot plate or steam bath or in an oven or furnace. Suitable temperatures include temperatures of about 60 ℃ to about 130 ℃ (e.g., about 100 ℃ to about 120 ℃). Alternatively, the drying step may be performed in a vacuum, for example using a rotary evaporator.

Optionally, the precipitated zinc and chromium hydroxide mixture may be collected and, if desired, washed with deionized water prior to drying. Preferably, the precipitated hydroxide mixture of zinc and chromium is not washed prior to the drying step.

After the zinc and chromium hydroxide mixture is dried, the nitrate is decomposed by heating the solid to about 250 ℃ to about 350 ℃. The resulting solid is then calcined at a temperature of from about 400 ℃ to about 1000 ℃, preferably from about 400 ℃ to about 900 ℃. Calcination may be carried out in a crucible or pot in an oven or furnace or in a tubular reactor. The calcination temperature can affect the activity of the catalyst as well as the product distribution. Lower calcination temperatures (i.e., calcination temperatures below about 500 ℃) may result in the presence of some residual nitrate impurities. The calcination is preferably carried out in the presence of oxygen, most preferably in the presence of air.

It is worth noting that ZnCr is contained₂O₄And crystalline alpha-chromium oxide, in which ZnCr is present₂O₄Formed in the calcination step.

Of note are the chromium-containing catalyst compositions of the invention comprising ZnCr₂O₄(zinc chromite) and crystalline alpha-chromium oxide, wherein ZnCr is in the composition₂O₄Contains from about 20 atomic% to about 50 atomic% chromium. Also of note are the chromium-containing catalyst compositions of the invention comprising ZnCr₂O₄(zinc chromite) and crystalline alpha-chromium oxide, wherein said ZnCr is in the composition₂O₄Contains at least about 90 atomic percent zinc. Also of note are chromium-containing catalyst compositions of the invention comprising zinc chromite and crystalline alpha-chromium oxide wherein greater than 95 atomic percent of the chromium not present as zinc chromite is present as crystalline alpha-chromium oxide. Also of note are the chromium-containing catalyst compositions of the invention consisting essentially of ZnCr₂O₄(Zinc chromite) and crystalline alpha-chromium oxideAnd (4) forming.

The compositions of the present invention can be characterized by well-established analytical techniques including Transmission Electron Microscopy (TEM), Energy Dispersive Spectroscopy (EDS) and X-ray diffraction. EDS in combination with scanning or analytical TEM is a powerful analytical tool.

The presence of zinc in various zinc and chromium oxide compositions of the invention is clearly indicated by elemental analysis using EDS. EDS analysis of various Cr/Zn oxide samples calcined at 900 c with Zn contents of 2, 5, 10 and 20 at% indicated the presence of two phases: a zinc chromite phase in which the content of Cr relative to Zn is 2 to 1, and a chromium oxide phase in which no zinc is found in the lattice (no Zn is detected in the EDS spectrum of this phase). For example, fig. 1 shows the EDS spectrum of a zinc chromite phase present in a zinc/chromium composition nominally containing 20 atomic% zinc. By way of comparison, FIG. 2 shows the α -Cr present in the same zinc/chromium composition nominally containing 20 atomic% zinc₂O₃EDS spectra of the phases. In each of these figures, the X-ray intensity I (expressed in kilocounts) is plotted against the energy level E (expressed in kilo electron volts (keV)). The peaks in each figure are related to the presence of certain elements. Calibration experiments have shown that in mixed zinc and chromium oxide compositions, the relative height of the metal K α peak reflects the molar ratio of zinc and chromium in the composition. Therefore, EDS spectroscopy is effective on a quantitative basis for those elements whose atomic masses are very similar. These results are also consistent with the wide angle X-ray diffraction analysis experiments for the various samples, which showed that each sample consisted of two phases: pure alpha-Cr₂O₃Phase and ZnCr₂O₄A spinel phase. Cr in this Cr/Zn sample compared to the zinc-free chromium oxide₂O₃The unit cell volume of the phase does not change significantly. This indicates that in Cr₂O₃No detectable substitution of Zn occurs in the crystal lattice. ZnCr₂O₄The weight percent of the phases increases with increasing zinc concentration.

The composition of the invention may further comprise one or more additives in the form of metal compounds which may modify the crystal contentBulk alpha-Cr₂O₃And ZnCr₂O₄Or fluorinated alpha-Cr₂O₃And ZnCr₂O₄Selectivity and/or activity of the catalyst composition. Suitable additives may be selected from the group consisting of fluorides, oxides or oxyfluorides of Mg, Ca, Zn, Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Mn, Re, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au and Ce.

In the compositions of the present invention, the total content of the additive can be from about 0.05 atomic% to about 15 atomic% based on the total metal content of the composition, with the proviso that when the additive is a compound of zinc, the additive contains less than 30 mole percent total zinc in the final composition. The additives may be incorporated into the compositions of the present invention by standard methods, such as impregnation of the additive solution followed by drying or co-precipitation.

The calcined zinc chromite/alpha-chromium oxide compositions of the invention may be compacted into various shapes, for example, into pellets for use in a packed reactor. It can also be used in powder form.

Typically, the calcined composition is pretreated with a fluorinating agent to alter the fluorine content of the halogenated hydrocarbon compound prior to use as a catalyst. Typically, this fluorinating agent is HF, although other materials such as sulfur tetrafluoride, carbonyl fluoride and fluorinated hydrocarbon compounds such as trichlorofluoromethane, dichlorodifluoromethane, chlorodifluoromethane, trifluoromethane or 1, 1, 2-trichlorotrifluoroethane may be used. This pretreatment is carried out, for example, by placing the catalyst in a suitable vessel, which may be the reactor used to carry out the process of the invention, after which the HF is passed through a dried, calcined catalyst to partially saturate the catalyst with HF. This may be conveniently carried out by passing HF over the catalyst at a temperature of, for example, from about 200 ℃ to about 450 ℃ for a period of time, for example, from about 0.1 to about 10 hours. However, such pretreatment is not necessary.

As mentioned above, the catalyst provided by the present invention can be used for changing the fluorine distribution and/or content in halogenated hydrocarbons. The catalysts of the present invention may also be usedFluorine is mixed into a saturated or unsaturated hydrocarbon. Methods for altering the distribution of fluorine in halogenated hydrocarbons include fluorination, chlorofluorination, isomerization, disproportionation, dehydrofluorination, and chlorodefluorination. Methods for incorporating fluorine into saturated or unsaturated hydrocarbons include chlorofluorination of saturated or unsaturated hydrocarbons and fluorination of unsaturated hydrocarbons. The method of the invention is characterized in that: using as catalyst at least one composition selected from the ZnCr compositions of the invention₂O₄Alpha-chromium oxide compositions and ZnCr of the invention which has been treated with a fluorinating agent₂O₄A/alpha-chromium oxide composition. Of note are processes in which the fluorine content of a halogenated hydrocarbon compound or an unsaturated hydrocarbon compound is increased by reacting the compound with hydrogen fluoride in the gas phase in the presence of the catalyst composition. Also of note are processes in which the fluorine content of a halogenated hydrocarbon compound or hydrocarbon compound is determined by reacting the compound with HF and Cl₂In the gas phase, in the presence of the catalyst composition. Also of note are processes in which the fluorine distribution in a halogenated hydrocarbon compound is altered by subjecting the halogenated hydrocarbon compound to isomerization in the presence of the catalyst composition. Also of note are processes in which the fluorine distribution in a halogenated hydrocarbon compound is altered by subjecting the halogenated hydrocarbon compound to disproportionation in the gas phase in the presence of the catalyst composition. Also of note are processes in which the fluorine content of a halogenated hydrocarbon compound is reduced by dehydrofluorinating the halogenated hydrocarbon compound in the presence of the catalyst composition. Also of note are processes in which the fluorine content of a halogenated hydrocarbon compound is reduced by reacting the halogenated hydrocarbon compound with hydrogen chloride in the gas phase in the presence of the catalyst composition.

Typical saturated halogenated hydrocarbons suitable for fluorination, chlorofluorination, isomerization, disproportionation, dehydrofluorination and chlorodefluorination processes are those having the formula C_nH_aBr_bCl_cF_dWherein n is an integer of 1 to 6, a is an integer of 0 to 12, b is an integer of 0 to 4, and c is an integer of 0 to 13An integer, d is an integer from 0 to 13, the sum of b, c and d is at least 1 and the sum of a, b, c and d is equal to 2n +2, with the proviso that n is at least 2 for isomerization, disproportionation and dehydrofluorination processes, a is at least 1 for dehydrofluorination processes, b is 0 for chlorine dehydrofluorination processes, b + c is at least 1 for fluorination processes, b + c is 0 for dehydrofluorination processes, a + b + c is at least 1 for fluorination, chlorofluorination, isomerization, disproportionation and dehydrofluorination processes, and d is at least 1 for isomerization, disproportionation, dehydrofluorination and chlorine dehydrofluorination processes. A typical saturated hydrocarbon compound suitable for chlorofluorination is a compound having the formula C_qH_rWherein q is an integer of 1 to 6 and r is 2q + 2. Typical unsaturated halogenated hydrocarbons suitable for fluorination, chlorofluorination, isomerization, disproportionation and chlorodefluorination processes are those having the formula C_pH_eBr_fCl_gF_hWherein p is an integer from 2 to 6, e is an integer from 0 to 10, f is an integer from 0 to 2, g is an integer from 0 to 12, h is an integer from 0 to 11, the sum of f, g and h is at least 1 and the sum of e, f, g and h is equal to 2p, with the proviso that f is 0 for the chlorine defluorination process, e + f + g is at least 1 for the isomerization and disproportionation process and h is at least 1 for the isomerization, disproportionation and chlorine defluorination process. Typical saturated hydrocarbons suitable for chlorofluorination are those having the formula C_qH_rWherein q is an integer of 1 to 6 and r is 2q + 2. Typical unsaturated hydrocarbons suitable for fluorination and chlorofluorination are those having the formula C_iH_jWherein i is an integer from 2 to 6 and j is 2 i.

Fluorination and chlorofluorination processes are typically carried out in the gas phase, in a tubular reactor, and at temperatures of about 150 ℃ to 500 ℃. For saturated compounds, fluorination is preferably carried out at a temperature of from about 175 ℃ to 400 ℃, more preferably from about 200 ℃ to about 350 ℃. For unsaturated compounds, fluorination is preferably carried out at a temperature of from about 150 ℃ to 350 ℃, more preferably from about 175 ℃ to about 300 ℃. The reaction is typically carried out at atmospheric and superatmospheric pressures. For convenience in downstream separation processes (e.g., distillation), pressures up to about 30 atmospheres can be used. The contact time in the reactor is typically from about 1 to about 120 seconds, preferably from about 5 to about 60 seconds.

The amount of HF reacted with the unsaturated hydrocarbon or halogenated hydrocarbon compound should be at least a stoichiometric amount. The stoichiometry is based on the number of Br and/or Cl substituents replaced by F, except for 1 mole of HF for saturated carbon-carbon double bonds (if present). Typically, HF is reacted with said formula C_nH_aBr_bCl_cF_d、C_pH_eBr_fCl_gF_hAnd C_iH_jThe molar ratio of the compounds may range from about 0.5: 1 to about 100: 1, preferably from about 2: 1 to about 50: 1, more preferably from about 3: 1 to about 20: 1. Generally, the higher the temperature and the longer the contact time, the greater the conversion to fluorinated products for a given catalyst composition. The above variables can be balanced one-to-one to maximize the formation of higher fluorine substituted products.

Formula C which can be reacted with HF in the presence of the catalyst according to the invention_nH_aBr_bCl_cF_dExamples of saturated compounds include CH₂Cl₂、CH₂Br₂、CHCl₃、CCl₄、C₂Cl₆、C₂BrCl₅、C₂Cl₅F、C₂Cl₄F₂、C₂Cl₃F₃、C₂Cl₂F₄、C₂ClF₅、C₂HCl₅、C₂HCl₄F、C₂HCl₃F₂、C₂HCl₂F₃、C₂HClF₄、C₂HBrF₄、C₂H₂Cl₄、C₂H₂Cl₃F、C₂H₂Cl₂F₂、C₂H₂ClF₃、C₂H₃Cl₃、C₂H₃Cl₂F、C₂H₃ClF₂、C₂H₄Cl₂、C₂H₄ClF、C₃Cl₆F₂、C₃Cl₅F₃、C₃Cl₄F₄、C₃Cl₃F₅、C₃HCl₇、C₃HCl₆F、C₃HCl₅F₂、C₃HCl₄F₃、C₃HCl₃F₄、C₃HCl₂F₅、C₃H₂Cl₆、C₃H₂BrCl₅、C₃H₂Cl₅F、C₃H₂Cl₄F₂、C₃H₂Cl₃F₃、C₃H₂Cl₂F₄、C₃H₂ClF₅、C₃H₃Cl₅、C₃H₃Cl₄F、C₃H₃Cl₃F₂、C₃H₃Cl₂F₃、C₃H₃ClF₄、C₃H₄Cl₄、C₄Cl₄Cl₄、C₄Cl₄Cl₆、C₄H₅Cl₅、C₄H₅Cl₄F and C₅H₄Cl₈。

Specific examples of fluorination reactions of saturated halogenated hydrocarbon compounds, which can be carried out under the above-mentioned conditions using the catalyst of the present invention, include CH₂Cl₂Conversion to CH₂F₂，CHCl₃Conversion to CHCl₂F、CHClF₂And CHF₃Mixture of (2), CH₃CHCl₂Conversion to CH₃CHClF and CH₃CHF₂Mixture of (2), CH₂ClCH₂Conversion of Cl to CH₃CHClF and CH₃CHF₂Mixture of (2), CH₃CCl₃Conversion to CH₃CCl₂F、CH₃CClF₂And CH₃CF₃Mixture of (2), CH₂ClCF₃Conversion to CH₂FCF₃，CHCl₂CF₃Conversion to CHClFCF₃And CHF₂CF₃Mixture of，CHClFCF₃Conversion to CHF₂CF₃，CHBrFCF₃Conversion to CHF₂CF₃，CCl₃CF₂CCl₃Conversion to CCl₂FCF₂CClF₂And CClF₂CF₂CClF₂Mixture of (C1), CCl₃CH₂CCl₃Conversion to CF₃CH₂CF₃Or conversion to CF₃CH₂CClF₂And CF₃CH₂CF₃Mixture of (C1), CCl₃CH₂CHCl₂Conversion to CF₃CH₂CHF₂、CF₃CH ═ CHCl and CF₃CH-CHF mixture, CF₃CCl₂CClF₂Conversion to CF₃CCl₂CF₃And CF₃CClFCF₃Mixture of (2), CF₃CCl₂CF₃Conversion to CF₃CClFCF₃And contains CF₃CF₂CHCl₂And CClF₂CF₂Conversion of mixtures of CHClF to CF₃CF₂CHClF and CF₃CF₂CHF₂A mixture of (a).

Formula C which can be reacted with HF in the presence of the catalyst according to the invention_pH_eBr_fCl_gF_hAnd C_iH_jExamples of the unsaturated compounds of (1) include C₂Cl₄、C₂BrCl₃、C₂Cl₃F、C₂Cl₂F₂、C₂ClF₃、C₂F₄、C₂HCl₃、C₂HBrCl₂、C₂HCl₂F、C₂HClF₂、C₂HF₃、C₂H₂Cl₂、C₂H₂ClF、C₂H₂F₂、C₂H₃Cl、C₂H₃F、C₂H₄、C₃H₆、C₃H₅Cl、C₃H₄Cl₂、C₃H₃Cl₃、C₃H₂Cl₄、C₃HCl₅、C₃Cl₆、C₃Cl₅F、C₃Cl₄F₂、C₃Cl₃F₃、C₃Cl₂F₄、C₃ClF₅、C₃HF₅、C₃H₂F₄、C₃F₆、C₄Cl₈、C₄Cl₂F₆、C₄ClF₇、C₄H₂F₆And C₄HClF₆。

Specific examples of fluorination reactions of unsaturated halogenated hydrocarbon compounds, which may be carried out using the catalysts of the present invention, include CHCl ═ CCl₂Conversion to CH₂ClCF₃And CH₂FCF₃Mixture of (C1), CCl₂＝CCl₂Conversion to CHCl₂CF₃、CHClFCF₃And CHF₂CF₃Mixture of (C1), CCl₂＝CH₂Conversion to CH₃CCl₂F、CH₃CClF₂And CH₃CF₃Mixture of (2), CH₂Conversion to CH₃CHClF and CH₃CHF₂Mixture of (2), CF₂＝CH₂Conversion to CH₃CF₃，CCl₂＝CClCF₃Conversion to CF₃CCl＝CF₂And CF₃CHClCF₃Mixture of (2), CF₃CF＝CF₂Conversion to CF₃CHFCF₃，CF₃CH＝CF₂Conversion to CF₃CH₂CF₃And CF₃Conversion of CH ═ CHF to CF₃CH₂CHF₂。

Also of note is the fluorination of one or more halopropene compounds CX₃Preparation of 2-chloro-1, 1,3, 3, 3-pentafluoropropene (i.e., CF ═ CCIX)₃CCl＝CF₂Or CFC-1215xc) and 2-chloro-1, 1, 1,3, 3, 3-hexafluoropropane (i.e., CF)₃CHClCF₃Or HCFC-226da) mixturesWherein each X is independently selected from F and Cl. Preferred formula CX₃CCl ═ CClX halopropenes include 1,2, 2-trichloro-3, 3, 3-trifluoro-1-propene (i.e., CCl)₂＝CClCF₃Or CFC-1213xa) and hexachloropropene (i.e., CCl₂＝CClCCl₃). The CFC-1215xc/HCFC-226da mixture is prepared by reacting the above unsaturated compound with HF in the vapor phase in the presence of the catalyst of the present invention at a temperature of from about 240 ℃ to about 400 ℃, preferably from about 250 ℃ to about 350 ℃.

At CX₃The amount of HF fed to the reactor should be at least stoichiometric based on the number of Cl substituents in the CCl ═ CClX starting material. In the case of fluorinated CFC-1213xa, the stoichiometric ratio of HF to CFC-1213xa for the synthesis of HCFC-226da is 3: 1. HF and CX₃The preferred ratio of CCl ═ CClX starting materials is typically in the range of about two times the stoichiometric ratio to about 30: 1. The preferred contact time is 1-60 seconds. In contrast to chromium oxide-containing catalyst compositions without zinc, the catalyst compositions of the present invention provide a mixture of CFC-1215xc and HCFC-226 da.

Details of the fluorination of CFC-1213xa to a mixture of CFC-1215xc and HCFC-226da are provided in U.S. patent application 60/511,354[ CL2372 USPRV ], filed 10/14/2003, which is incorporated herein by reference in its entirety (see also corresponding International application No. PCT/US 2004/_____).

Mixtures of saturated halogenated hydrocarbon compounds or mixtures of unsaturated hydrocarbons and/or halogenated hydrocarbon compounds as well as mixtures containing both unsaturated hydrocarbons and halogenated hydrocarbon compounds may also be used in the gas phase fluorination reaction. Specific examples of mixtures of saturated halogenated hydrocarbon compounds and mixtures of unsaturated hydrocarbons and unsaturated halogenated hydrocarbon compounds that can be gas phase fluorinated using the catalyst of the present invention include CH₂Cl₂And CCl₂＝CCl₂Mixture of (C1), CCl₂FCClF₂And CCl₃CF₃Mixture of (C1), CCl₂＝CCl₂And CCl₂＝CClCCl₃Mixture of (2), CH₂＝CHCH₃And CH₂＝CClCH₃Mixture of (2), CH₂Cl₂And CH₃CCl₃Mixture of (1), CHF₂CClF₂And CHClFCF₃Mixture of (1), CHCl₂CCl₂CH₂Cl and CCl₃CHClCH₂Mixture of Cl, CHCl₂CH₂CCl₃And CCl₃CHClCH₂Mixture of Cl, CHCl₂CHClCCl₃、CCl₃CH₂CCl₃And CCl₃CCl₂CH₂Mixture of Cl, CHCl₂CH₂CCl₃And CCl₃CH₂CCl₃Mixture of (2), CF₃CH₂CCl₂F and CF₃CH＝CCl₂And CF, and₃CH ═ CHCl and CF₃CH＝CCl₂A mixture of (a).

If chlorine (Cl) is present in the chlorofluorination reaction₂) The amount of chlorine fed to the reactor is then based on whether the halogenated hydrocarbon compound fed to the reactor is unsaturated, and is in C_nH_aBr_bCl_cF_d、C_qH_r、C_pH_eBr_fCl_gF_hAnd C_iH_jThe number of hydrogens to be replaced by chlorine and fluorine. To saturate the carbon-carbon double bond, 1 mole of Cl is required₂1 mol of Cl is required for each hydrogen replaced by chlorine or fluorine₂. For practical reasons, a slight excess of chlorine over the stoichiometric amount may be required, but a large excess of chlorine will result in complete chlorofluorination of the product. Cl₂The ratio to halogenated hydrocarbon compound is typically from about 1: 1 to about 10: 1.

General formula C which can be carried out using the catalysts of the invention_nH_aBr_bCl_cF_dAnd a saturated halogenated hydrocarbon compound of the formula C_qH_rSpecific examples of the gas phase chlorofluorination reaction of saturated hydrocarbon compounds of (a) include: c₂H₆Conversion to CH-containing₂ClCF₃Mixture of (2), CH₂ClCF₃Conversion to CHClFCF₃And CHF₂CF₃Mixture of (C1), CCl₃CH₂CH₂Conversion of Cl to CF₃CCl₂CClF₂、CF₃CCl₂CF₃、CF₃CClFCClF₂And CF₃CClFCF₃Mixture of (C1), CCl₃CH₂CHCl₂Conversion to CF₃CCl₂CClF₂、CF₃CCl₂CF₃、CF₃CClFCClF₂And CF₃CClFCF₃Mixture of (C1), CCl₃CHClCH₂Conversion of Cl to CF₃CCl₂CClF₂、CF₃CCl₂CF₃、CF₃CClFCClF₂And CF₃CClFCF₃Mixture of (1), CHCl₂CCl₂CH₂Conversion of Cl to CF₃CCl₂CClF₂、CF₃CCl₂CF₃、CF₃CClFCClF₂And CF₃CClFCF₃Mixture of (C1), CCl₃CH₂CH₂Conversion of Cl to CF₃CCl₂CHF₂、CF₃CClFCHF₂、CF₃CClFCClF₂And CF₃CCl₂CF₃And CCl, and₃CH₂CHCl₂conversion to CF₃CCl₂CHF₂、CF₃CClFCHF₂、CF₃CClFCClF₂And CF₃CCl₂CF₃A mixture of (a).

General formula C which can be carried out using the catalysts of the invention_pH_eBr_fCl_gF_hAnd an unsaturated halogenated hydrocarbon compound of the formula C_iH_jSpecific examples of the gas phase chlorofluorination reaction of unsaturated hydrocarbon compounds of (a) include: c₂H₄Conversion to CCl₃CClF₂、CCl₂FCCl₂F、CClF₂CClF、CCl₃CF₃、CF₃CCl₂F and CClF₂CClF₂Mixture of (A) and (B), C₂Cl₄Conversion to CCl₃CClF₂、CCl₂FCCl₂F、CClF₂CCl₂F、CCl₃CF₃、CF₃CCl₂F and CClF₂CClF₂A mixture of (A) and (B), and₃H₆or CF₃CCl＝CCl₂Conversion to CF₃CCl₂CClF₂、CF₃CCl₂CF₃、CF₃CClFCClF₂And CF₃CClFCF₃A mixture of (a).

Of note is a compound of formula CX via chlorofluorination₃Halogenated propenes of CCl ═ CClX to produce 1,2, 2-trichloro-1, 1,3, 3, 3-pentafluoropropane (i.e., CClF)₂CCl₂CF₃Or CFC-215aa) and 1, 1, 2-trichloro-1, 2, 3, 3, 3-pentafluoropropane (i.e., CF)₃CClFCCl₂F or CFC-215bb), wherein each X is independently selected from F and Cl. Preferred formula CX₃Halopropenes of CCl ═ CClX include 1,2, 2-trichloro-3, 3, 3-trifluoro-1-propene (i.e., CCl)₂＝CClCF₃Or CFC-1213xa) and hexachloropropene (i.e., CCl₂＝CClCCl₃). Mixtures of CFC-215aa and CFC-215bb may be prepared by reacting the unsaturated compounds mentioned above with Cl₂And HF are prepared by reaction in the gas phase in the presence of the catalyst of the present invention at a temperature of from about 200 ℃ to about 400 ℃, preferably from about 250 ℃ to about 350 ℃.

Details of chlorofluorination of CFC-1213xa to prepare CFC-215aa and CFC-215bb are provided in U.S. patent application 60/511,284[ CL2320 US PRV ] filed on 14.10.2003, which is incorporated herein by reference in its entirety (see also corresponding International application No. PCT/US 2004/_____).

Also of note is a compound of formula CX via chlorofluorination₃CCl＝CX₂To produce 2, 2-dichloro-1, 1, 1,3, 3, 3-hexafluoropropane (i.e., CF)₃CCl₂CF₃Or CFC-216aa) and 1, 2-dichloro-1, 1,2, 3, 3, 3-hexafluoropropane (i.e., CF)₃CClFCClF₂Or CFC-216ba), wherein each X is independently selected fromF and Cl. Preferred formula CX₃Halopropenes of CCl ═ CClX include 1,2, 2-trichloro-3, 3, 3-trifluoro-1-propene (i.e., CCl)₂＝CClCF₃Or CFC-1213xa) and hexachloropropene (i.e., CCl₂＝CClCCl₃). Mixtures of CFC-216aa and CFC-216ba may be prepared by reacting the above unsaturated compounds with Cl₂And HF are prepared by reaction in the gas phase in the presence of the catalyst of the present invention at a temperature of from about 230 ℃ to about 425 ℃, preferably from about 250 ℃ to about 400 ℃.

Details of chlorofluorination of CFC-1213xa to prepare CFC-216aa and CFC-216ba are provided in U.S. patent application 60/511,355[ CL2246 US PRV ], filed on 14.10.2003, which is incorporated herein by reference in its entirety (see also corresponding International application No. PCT/US 2004/_____).

Mixtures of saturated hydrocarbon compounds and saturated halogenated hydrocarbon compounds, mixtures of unsaturated hydrocarbon compounds and unsaturated halogenated hydrocarbon compounds, and mixtures comprising both saturated and unsaturated compounds can be chlorofluorinated using the catalyst of the present invention. Specific examples of saturated and unsaturated hydrocarbons and halogenated hydrocarbon mixtures that may be used include: CCl₂＝CCl₂And CCl₂＝CClCCl₃Mixture of (1), CHCl₂CCl₂CH₂Cl and CCl₃CHClCH₂Mixture of Cl, CHCl₂CH₂CCl₃And CCl₃CHClCH₂Mixture of Cl, CHCl₂CHClCCl₃、CCl₃CH₂CCl₃And CCl₃CCl₂CH₂Mixtures of Cl, CHF₂CH₂CF₃And CHCl ═ CHCF₃And CH₂＝CH₂And CH₂＝CHCH₃A mixture of (a).

The invention also includes embodiments wherein the fluorine distribution of the halogenated hydrocarbon compound is altered by rearranging the H, Br, Cl and F substituents in the molecule (typically to become thermodynamically preferred arrangements) while maintaining the same number of H, Br, Cl and F substituents, respectively. This process is referred to herein as isomerization.

In another embodiment of the invention, the fluorine distribution of the halogenated hydrocarbon compound is altered by exchanging at least one F substituent of one molecule of the halogenated hydrocarbon starting material for at least one H, Br and/or Cl substituent of another molecule of the halogenated hydrocarbon starting material to produce one or more halogenated hydrocarbon compounds having a reduced fluorine content (as compared to the halogenated hydrocarbon starting material) and one or more halogenated hydrocarbon compounds having an increased fluorine content (as compared to the halogenated hydrocarbon starting material). This process is referred to herein as disproportionation.

In another embodiment of the invention, both isomerization and disproportionation reactions may be present simultaneously.

Whether isomerization, disproportionation, or both isomerization and disproportionation are carried out in the presence of the catalyst composition of the present invention, formula C_nH_aBr_bCl_cF_dAnd/or a saturated compound of the formula C_pH_eBr_fCl_gF_hThe fluorine distribution in the unsaturated compound(s) of (a) may vary.

The isomerization and disproportionation reactions are typically carried out at temperatures of about 150 ℃ to 500 ℃, preferably about 200 ℃ to about 400 ℃. The contact time in the reactor is typically from about 1 to about 120 seconds, preferably from about 5 to about 60 seconds. The isomerization and disproportionation may be carried out in the presence of an inert gas such as helium, argon or nitrogen. The isomerization and disproportionation reactions may be carried out in the presence of HF and HCl.

Specific examples of vapor phase isomerization reactions that can be carried out using the catalyst of the present invention include: CClF₂CCl₂Conversion of F into CCl₃CF₃，CClF₂CClF₂Conversion to CF₃CCl₂F，CHF₂CClF₂Conversion to CF₃CHClF，CHF₂CHF₂Conversion to CF₃CH₂F，CF₃CClFCClF₂Conversion to CF₃CCl₂CF₃And CF₃CHFCHF₂Conversion to CF₃CH₂CF₃。

Specific examples of the gas phase disproportionation reaction which can be carried out using the catalyst of the present invention include: CClF₂CClF₂Conversion to CClF₂CCl₂F、CCl₃CF₃And CF₃CClF₂And CHClFCF, and₃conversion to CHCl₂CF₃And CHF₂CF₃A mixture of (a).

Of note for the following process is that the process employs 2-chloro-1, 1,2, 2-tetrafluoroethane (i.e., CHF)₂CClF₂Or HCFC-124a) and 2-chloro-1, 1, 1, 2-tetrafluoroethane (i.e., CF)₃CHClF or HCFC-124) to 2, 2-dichloro-1, 1, 1-trifluoroethane (i.e., CHCl)₂CF₃Or HCFC-123) and 1, 1, 1,2, 2-pentafluoroethane (i.e., CF)₃CHF₂Or HFC-125), the product mixture also containing unconverted starting material. Mixtures containing HFC-125 and HCFC-123 may be obtained by contacting in the gaseous phase a mixture of HCFC-124a and HCFC-124 with the catalyst of the invention, optionally in the presence of a diluent selected from HF, HCl, nitrogen, helium, argon and carbon dioxide. The disproportionation reaction is preferably carried out at a temperature of about 150 ℃ to about 400 ℃, more preferably about 250 ℃ to about 350 ℃. If used, the diluent gas may be present in a molar ratio of diluent to haloethane in the range of from about 1: 1 to about 5: 1. Preferred contact times are from about 10 seconds to about 60 seconds.

The present invention includes a process for reducing the fluorine content of a halogenated hydrocarbon compound by dehydrofluorinating said halogenated hydrocarbon compound in the presence of a catalyst of the present invention. Halogenated hydrocarbon compounds suitable as starting materials for the dehydrofluorination process of the invention include those of the general formula C_nH_aF_dWherein n is an integer from 2 to 6, a is an integer from 1 to 12, d is an integer from 1 to 13, and the sum of a and d is equal to 2n + 2.

The dehydrofluorination reaction is typically carried out at a temperature of from about 200 ℃ to about 500 ℃, preferably from about 300 ℃ to about 450 ℃. The contact time in the reactor is typically from about 1 to about 360 seconds, preferably from about 5 to about 120 seconds. The dehydrofluorination reaction may also be carried out in the presence of an inert gas such as helium, argon or nitrogen to increase the degree of dehydrofluorination of the halogenated hydrocarbon compound.

The product of the dehydrofluorination reaction consists of HF and the unsaturated fluorocarbon compound produced by the loss of HF from the starting material. Specific examples of vapor phase dehydrofluorination reactions which can be carried out using the catalyst of the present invention include CH₃CHF₂Conversion to CH₂＝CHF，CH₃CF₃Conversion to CH₂＝CF₂，CF₃CH₂Conversion of F to CF₂＝CHF，CHF₂CH₂CF₃Conversion to CHF ═ CHCF₃And CF₃CH₂CF₃Conversion to CF₃CH＝CF₂。

Of note is a process through 1, 1-difluoroethane (i.e., CHF)₂CH₃Or HFC-152a) dehydrofluorination to produce fluoroethylene (i.e., CH)₂CHF or vinyl fluoride). The mixture comprising fluoroethylene and unconverted HFC-152a can be obtained in the gas phase by contacting HFC-152a with the catalyst of the present invention, optionally in the presence of a diluent selected from the group consisting of HF, nitrogen, helium, hydrogen and carbon dioxide. The dehydrofluorination reaction is preferably carried out at a temperature of from about 150 ℃ to about 400 ℃, more preferably from about 250 ℃ to about 350 ℃. If used, the diluent gas may be present in a molar ratio of diluent to haloethane in the range of from about 1: 1 to about 5: 1. Preferred contact times are from about 10 seconds to about 60 seconds.

Also of note is a reaction through 1, 1, 1,3, 3, 3-hexafluoropropane (i.e., CF)₃CH₂CF₃Or HFC-236fa) dehydrofluorination to 1, 1,3, 3, 3-pentafluoropropene (i.e., CF)₂＝CHCF₃Or HFC-1225 zc). A mixture comprising HFC-1225zc and unconverted HFC-236fa can be obtained in the vapour phase by contacting HFC-236fa with the catalyst of the present invention, optionally in the presence of a diluent selected from the group consisting of HF, nitrogen, helium, argon and carbon dioxide. The dehydrofluorination reaction is preferably at aboutFrom 250 ℃ to about 450 ℃, more preferably from about 300 ℃ to about 400 ℃. If used, the diluent gas may be present in a molar ratio of diluent to haloethane in the range of from about 1: 1 to about 5: 1. Preferred contact times are from about 10 seconds to about 60 seconds.

The present invention includes a process for reducing the fluorine content of a halogenated hydrocarbon compound by reacting the halogenated hydrocarbon compound with hydrogen chloride (HCl) in the gas phase in the presence of the catalyst composition of the present invention. Such a process is referred to herein as chlorofluorination. Chlorine defluorination is disclosed in U.S. patent No. 5,345,017 and U.S. patent No. 5,763,698, both of which are incorporated herein by reference.

For the chlorine defluorination process of the present invention, the halogenated hydrocarbon compounds suitable as starting materials may be saturated or unsaturated. Saturated halogenated hydrocarbon compounds suitable for the chlorine defluorination process of the present invention include those of formula C_nH_aCl_cF_dWherein n is an integer from 1 to 6, a is an integer from 0 to 12, c is an integer from 0 to 13, d is an integer from 1 to 13, and the sum of a, c and d is equal to 2n + 2. Unsaturated halogenated hydrocarbon compounds suitable for use in the chlorine defluorination process of the present invention include those of formula C_pH_eCl_gF_hWherein p is an integer from 2 to 6, e is an integer from 0 to 10, g is an integer from 0 to 12, h is an integer from 1 to 11, and the sum of e, g and h is equal to 2 p. Formula C_nH_aCl_cF_dAnd/or a saturated compound of the formula C_pH_eCl_gF_hThe fluorine content of the unsaturated compound(s) of (a) can be reduced by reacting said compound(s) with HCl in the gas phase in the presence of the catalyst composition of the invention.

The product of the chlorine defluorination reaction typically comprises unreacted HCl, HF, unconverted starting material, saturated halogenated hydrocarbon compounds having a lower fluorine content than the starting material, and unsaturated halogenated compounds. Specific examples of gas phase chlorine defluorination reactions that may be carried out using the catalyst of the present invention include: CHF₃Conversion to CHCl₃、CHCl₂F and CHClF₂Mixture of (C) CClF₂CClF₂Conversion to CCl₃CCl₃、CCl₃CCl₂F、CCl₃CClF₂、CCl₂FCCl₂F、CClF₂CCl₂F and CCl₃CF₃Mixture of (2), CF₃CClF₂Conversion to CCl₃CCl₃、CCl₃CCl₂F、CCl₃CClF₂、CCl₂FCCl₂F、CClF₂CCl₂F、CCl₃CF₃、CClF₂CClF₂And CF₃CCl₂Mixture of F, CF₃CCl₂CF₃Conversion to CF₃CCl₂CClF₂、CF₃CCl₂CCl₂F、CF₃CCl₂CCl₃And CClF₂CCl₂CCl₃And CF, and₃CH₂CF₃conversion to CCl₂＝CHCF₃And CCl₂＝CClCF₃A mixture of (a).

The reaction product obtained by the process of the present invention may be isolated by conventional techniques, such as by a combination including, but not limited to, washing, decanting or distillation. Some products of various embodiments of the invention may form one or more azeotropes with each other or with HF.

The reactor, distillation column and associated feed, discharge and associated units used in the process of the invention should be constructed of materials resistant to hydrogen fluoride and hydrogen chloride. Typical materials of construction known in the fluorination art include stainless steels, particularly austenitic steels, known high nickel alloys, such as Monel^TMCopper-nickel alloys, Hastelloy^TMNickel-based alloy and Inconel^TMNichrome alloys, and copper plated steel.

The method of the present invention can be easily carried out using well-known chemical engineering practices.

Practicality of use

Part of the reaction product obtained by using the catalyst disclosed herein has a structure for straighteningTo meet the desired properties for commercial use. For example, find CH₂F₂(HFC-32)、CHF₂CF₃(HFC-125)、CHF₂CF₃(HFC-125)、CH₂FCHF₂(HFC-134)、CF₃CH₂CF₃(HFC-236fa) and CF₃CH₂CHF₂(HFC-245fa) as a refrigerant, found CH₂FCF₃(HFC-134a) and CF₃CHFCF₃(HFC-227ea) as a propellant, found CH₂FCHF₂(HFC-134) and CF₃CH₂CHF₂(HFC-245fa) as a blowing agent, and the discovery of CHF₂CF₃(HFC-125)、CF₃CH₂CF₃(HFC-236fa) and CF₃CHFCF₃(HFC-227ea) as a fire extinguishing agent.

Other reaction products obtained by using the present invention are used as chemical intermediates to prepare useful products. For example, CCl₃CF₃(CFC-113a) can be used to prepare CFC-114a, which can be converted to CH by hydrodechlorination₂FCF₃(HFC-134 a). Similarly, CF₃CCl₂CF₃(CFC-216aa) and CF₃CHClCF₃(HCFC-226da) can be used to prepare CF by hydrodechlorination₃CH₂CF₃(HFC-236 fa). Further, CF₃CCl＝CF₂(CFC-1215xc) and CF₃CCl₂CClF₂(CFC-215aa) can be used for the preparation of CF by hydrogenation₃CH₂CHF₂(HFC-245fa), and CF₃CClFCClF₂(CFC-216ba) can be used to prepare CF₃CF＝CF₂(HFP)。

The following specific embodiments are to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

Examples

(Code)

CFC-113 is CClF₂CCl₂F CFC-114 is CClF₂CClF₂

CFC-114a is CF₃CCl₂F HCFC-124 is CF₃CHClF

HCFC-124a is CClF₂CHF₂HFC-125 is CF₃CHF₂

CFC-133a is CF₃CH₂Cl 226da is CF₃CHClCF₃

227ea is CF₃CHFCF₃236fa is CF₃CH₂CF₃

HCC-1110 is CCl₂＝CCl₂CFC-1111 is CClF ═ CCl₂

HCC-1120 is CHCl ═ CCl₂HCFC-1121 is CHCl ═ CClF

1215xc is CF₃CCl＝CF₂1225zc is CF₃CH＝CF₂

Catalyst characterization

Energy Dispersive Spectroscopy (EDS) and Transmission Electron Microscopy (TEM)

In these studies, the microcrystals were analyzed using a Philips CM-20 high resolution transmission electron microscope, operating at an accelerating voltage of 200kV and equipped with an Oxford windowless EDS system with a Si (Li) element detector. In EDS analysis, an electronically transparent sheet of the sample minimizes sample thickness effects such as fluorescence. Furthermore, since their atomic masses are similar, the X-ray absorption cross-sections of Cr and Zn are assumed to be the same (see Zaluzec discussion on page 121-. The presence of copper in EDS is due to the TEM grid and background in the microscope.

X-ray powder diffraction (XRD)

X-ray diffraction measurements were performed using a Philips XPERT automated powder diffractometer model 3040, collected using CuK (α) radiation (λ ═ 1.5406 ). These measurements included scans at 2-90 deg. 2-theta with steps of 0.03 deg., and a count time of 2 seconds. Volume size and weight percent were determined using GSAS software and Rietveld method. The volume average crystallite size was estimated using Materials Data Jade software.

Catalyst preparation

Preparation of example 1

Preparation of 95% chromium/5% Zinc catalyst (450 ℃ C.)

Preparation of 380.14g Cr (NO) in 1000ml deionized water₃)₃[9(H₂O)](0.950 mol) and 14.87g Zn (NO)₃)₂[6(H₂O)](0.050 moles). The solution was treated with 450ml of 7.4M ammonia in the course of 1 hour; the pH increased from 1.7 to 8.4. The slurry was stirred at room temperature overnight and then dried in an oven in the presence of air at 120 ℃. Then, the dried solid was calcined in air at 450 ℃ for 20 hours; 76.72g of solid were obtained.

Preparation of example 2

Preparation of 90% chromium/10% Zinc catalyst (900 ℃ C.)

Preparation of 360.13g Cr (NO) in 1000ml deionized water₃)₃[9(H₂O)](0.900 mol) and 29.75g Zn (NO)₃)₂[6(H₂O)](0.100 mol) of a solution. The solution was treated with 450ml of 7.4M ammonia in the course of 1.4 hours; the pH increased from 1.9 to 8.4. The slurry was stirred at room temperature overnight and then dried at 120 ℃ in the presence of air. Then, the dried solid was calcined in air at 900 ℃ for 20 hours; 75.42g of a solid were obtained.

X-ray powder analysis of the sample indicated the presence of three phases: internal standard of silicon, Cr₂O₃(Green chromium ore) and ZnCr₂O₄(zinc chromite). ZnCr₂O₄The wt% of (c) was determined to be 23.9%. With Cr calcined at 900 DEG C₂O₃Sample (which had precipitated in the absence of zinc) (0.2895 nm)³) In contrast, the unit cell volume of the Cr/Zn sample did not change significantly (0.2896 nm)³). This indicates that zinc is not substituted for Cr₂O₃In the crystal lattice. Cr (chromium) component₂O₃And ZnCr₂O₄The estimated coherence domain (coherent domain) size of the phase is 814 and 712 angstroms, respectively.

The samples were analyzed by TEM and EDS and showed the presence of a zinc-containing chromium oxide phase and a zinc-free chromium oxide phase with a Cr/Zn ratio of 2.

Preparation of example 3

Preparation of 95% chromium/5% Zinc catalyst (900 ℃ C.)

Preparation of 380.14g Cr (NO) in 1000ml deionized water₃)₃[9(H₂O)](0.950 mol) and 14.87g Zn (NO)₃)₂[6(H₂O)](0.050 moles). The solution was treated with 450ml of 7.4M ammonia in the course of one hour; the pH increased from 1.7 to 8.4. The slurry was stirred at room temperature overnight and then dried in an oven in the presence of air at 120 ℃. Then, the dried solid was calcined in air at 900 ℃ for 20 hours; 70.06g of solid were obtained.

X-ray powder analysis of the sample indicated the presence of three phases: internal standard of silicon, Cr₂O₃(Green chromium ore) and ZnCr₂O₄(zinc chromite). ZnCr₂O₄The wt% of (D) was determined to be 12.1%. With Cr calcined at 900 DEG C₂O₃Sample (which had precipitated in the absence of zinc) (0.2895 nm)³) In contrast, the unit cell volume of the Cr/Zn sample did not change significantly (0.2894 nm)³). This indicates that zinc is not substituted for Cr₂O₃In the crystal lattice. Cr (chromium) component₂O₃And ZnCr₂O₄The estimated coherent domain sizes of the phases are 962 angstroms and 913 angstroms, respectively.

The samples were analyzed by TEM and EDS and showed the presence of a zinc-containing chromium oxide phase and a zinc-free chromium oxide phase with a Cr/Zn ratio of 2.

Preparation of example 4

Preparation of 80% chromium/20% Zinc catalyst (900 ℃ C.)

Preparation of 320.12g Cr (NO) in 1000ml deionized water₃)₃[9(H₂O)](0.800 moles) and 59.49g Zn (NO)₃)₂[6(H₂O)](0.200 mol) of a solution. The solution was treated with 450ml of 7.4m ammonia in the course of one hour; the pH increased from about 1.7 to about 8.4. The slurry was stirred at room temperature overnight and then dried in an oven in the presence of air at 120 ℃. Then, the dried solid was calcined in air at 900 ℃ for 22 hours; 75.80g of solid were obtained.

X-ray powder analysis of the sample indicated the presence of three phases: internal standard of silicon, Cr₂O₃(Green chromium ore) and ZnCr₂O₄(zinc chromite). ZnCr₂O₄The wt% of (D) was determined to be 60.9%. With Cr calcined at 900 DEG C₂O₃Sample (which had precipitated in the absence of zinc) (0.2895 nm)³) In contrast, the unit cell volume of the Cr/Zn sample did not change significantly (0.2896 nm)³). This indicates that zinc is not substituted for Cr₂O₃In the crystal lattice. Cr (chromium) component₂O₃And ZnCr₂O₄The estimated coherent domain sizes of the phases are 779 angstroms and 679 angstroms, respectively.

The samples were analyzed by TEM and EDS and showed the presence of a zinc-containing chromium oxide phase and a zinc-free chromium oxide phase with a Cr/Zn ratio of 2.

Preparation of example 5

Preparation of 98.1% chromium/1.9% Zinc catalyst (550 ℃ C.)

516.46gCr (NO) was prepared in 500ml of distilled water in a 1L beaker placed on a hot plate₃)₃[9(H₂O)](1.29 mol) and 7.31g Zn (NO)₃)₂[6(H₂O)](0.0246 mol). The mixture was then transferred to Pyrex^TMIn a container and placing the container in an oven. The vessel was heated from room temperature to 125 ℃ at a rate of 10 ℃/min and then held at 125 ℃ for 6 hours. The vessel was heated from 125 ℃ to 350 ℃ at a rate of 1 ℃/min and then held at 350 ℃ for 6 hours. The vessel was heated from 350 ℃ to 550 ℃ at a rate of 1 ℃/min and then held at 550 ℃ for 24 hours.

Example 1

CF₃CH₂CF₃Dehydrofluorination

A sample of the catalyst prepared in preparation example 5 was pelletized (-12 to +20 mesh, (1.68 to 0.84 mm)); 29.86g (20mL) and sieved, then placed in 5/8' (1.58cm) diameter Inconel heated in a fluidized sand bath^TMIn a nickel alloy reactor tube. Before use, the catalyst was purged with nitrogen at about 250 ℃. Furthermore, the catalyst, which has previously been used in chlorofluorination reactions, was first treated with a 1: 1 ratio of HF to nitrogen (50cc/min (8.3 (10))^-7m³Sec) each) was fluorinated at 175 ℃. Then, as the reactor temperature was gradually increased from 175 ℃ to 400 ℃ over several hours, the catalyst was treated with HF and nitrogen in a ratio of 4: 1 (nitrogen flow rate: 20cc/min (3.3 (10))^-7m³Sec); HF flow rate: 80cc/min (1.3(10)^-6m³Sec). HFC-236fa and nitrogen were fed into the reactor at a 1: 4 molar ratio and contacted with the catalyst at a nominal pressure of one atmosphere for a period of 15 seconds. The results of GC-MS analysis of the reactor effluent at 300 ℃ and 400 ℃ are shown below.

Mol% of

Components	300℃	400℃
			HFC-236faHFC-1225zcHFC-227ea	92.36.80.6	59.736.23.1

The minor product comprises CH₃CF₃、C₃F₈、C₄HF₇、CF₃CHClCF₃And C₃HClF₄。

Example 2

CF₃CHClCF₃/CF₃CH₂CF₃Dehydrofluorination of mixtures

A sample of the catalyst prepared in preparation example 2 was pelletized (-12 to +20 mesh, (1.68 to 0.84 mm)); 26.64g (15mL) and sieved, followed by 5/8' (1.58cm) diameter Inconel heated in a fluidized sand bath^TMIn a nickel alloy reactor tube. Before use, the catalyst was purged with nitrogen at about 250 ℃. Furthermore, the catalyst, which had previously been used in chlorofluorination reactions, was first fluorinated in a manner similar to that in example 1. Nitrogen is fed to the reactor together with a mixture containing HCFC-226da (73.9%), HFC-236fa (25.5%), HFC-1225zc (0.2%) and CFC-216aa (0.1%) and is contacted with the catalyst at a nominal pressure of one atmosphere for a period of 30 seconds. Moles of Nitrogen on fluoropropane mixtureThe ratio is 4: 1. The results of GC-MS analysis of the reactor effluent at 300 ℃ and 400 ℃ are shown below.

GC area%

Components	300℃	400℃
			HCFC-226daHFC-236faHFC-1225zcCFC-1215xc	73.224.71.50.2	51.415.311.317.0

The minor product comprises CH₃CF₃、C₃H₃F₃、C₃H₂F₄、CF₃CF＝CHF、CF₃CHClCF₃、C₃HClF₄、C₃Cl₂F₆And C₃Cl₂F₄。

Example 3

CF₃CHClF/CClF₂CHF₂Disproportionation of the mixture

Nitrogen was fed together with a mixture containing HCFC-124a (97.1 mol%), HCFC-124(2.4 mol%) and CFC-114(0.4 mol%) to the reactor containing the catalyst used in example 2. The molar ratio of nitrogen to the 124/124a mixture was 2: 1 and the contact time was 30 seconds. The results of GC-MS analysis of the reactor effluent at 300 ℃ and 400 ℃ are shown below.

Mol% of

Components	300℃	400℃
			HFC-125HCFC-124	1.52.1	21.43.7

HCFC-124aCFC-133aC2HCl2F3Isomer HCC-1110HCC-1120CFC-1111C2Cl2F2Isomer HCFC-1121CFC-114aCFC-114CFC-113

94.9-0.7--0.030.060.02-0.4-

61.92.13.30.51.42.21.70.72.10.40.3

The secondary product comprises CF₃CH₂CF₃、CF₃CH₂Cl、C₃HF₅、CF₃CHClCF₃、C₂HCl₃F₂、C₂Cl₂F₄、C₂ClF₅And C₂Cl₂F₂。

Claims (16)

1. A chromium-containing catalyst composition comprising:

ZnCr₂O₄(ii) a And

crystalline alpha-chromium oxide;

wherein ZnCr is present in the composition₂O₄Containing from about 10 to 67 at% chromium and at least about 70 at% zinc, and wherein at least about 90 at% of the chromium present in the composition as chromium oxide is ZnCr₂O₄Or crystalline alpha-chromium oxide.

2. The chromium-containing catalyst composition of claim 1 wherein the ZnCr is in the composition₂O₄Contains from about 20 atomic% to about 50 atomic% chromium.

3. The chromium-containing catalyst composition of claim 1 wherein the ZnCr is in the composition₂O₄Contains at least about 90 atomic percent zinc.

4. The chromium-containing catalyst composition of claim 1 wherein greater than 95% of the chromium not present as zinc chromite is present as crystalline α -chromium oxide.

5. The chromium-containing catalyst composition of claim 1 consisting essentially of ZnCr₂O₄And crystalline alpha-chromium oxide.

6. A chromium-containing catalyst composition prepared by treating the composition of claim 1 with a fluorinating agent.

7. The chromium-containing catalyst composition of claim 6 wherein said fluorinating agent is anhydrous hydrogen fluoride.

8. A process for changing the distribution of fluorine in a halogenated hydrocarbon or introducing fluorine into a saturated or unsaturated hydrocarbon in the presence of a catalyst, characterized in that: using as a catalyst at least one composition selected from the group consisting of (i) the chromium-containing catalyst composition of claim 1 and (ii) a chromium-containing catalyst composition prepared by treating the composition of claim 1 with a fluorinating agent.

9. The process of claim 8, wherein the fluorine content of the halogenated hydrocarbon compound or unsaturated hydrocarbon compound is increased by reacting said compound with hydrogen fluoride in the gas phase in the presence of said catalyst composition.

10. The process of claim 8 wherein the halogenated hydrocarbon compoundOr the fluorine content of hydrocarbon compounds by reacting said compounds with HF and Cl₂In the gas phase, in the presence of the catalyst composition.

11. The process of claim 8 wherein the fluorine distribution in a halogenated hydrocarbon compound is altered by isomerizing the halogenated hydrocarbon compound in the presence of the catalyst composition.

12. The process of claim 8 wherein the fluorine distribution in the halogenated hydrocarbon compound is altered by disproportionation of said halogenated hydrocarbon compound in the vapor phase in the presence of said catalyst composition.

13. The process of claim 8, wherein the fluorine content in a halogenated hydrocarbon compound is reduced by dehydrofluorinating said halogenated hydrocarbon compound in the presence of said catalyst composition.

14. The process of claim 8 wherein the fluorine content of the halogenated hydrocarbon compound is reduced by reacting said halogenated hydrocarbon compound with hydrogen chloride in the gas phase in the presence of said catalyst composition.

15. A method of making the chromium-containing catalyst composition of claim 1 comprising:

(a) coprecipitating solids by adding ammonium hydroxide to an aqueous solution of a soluble zinc salt and a soluble trivalent chromium salt, wherein said aqueous solution contains at least 3 moles of nitrate per mole of chromium and wherein the concentration of zinc in said solution is from about 5 mole% to about 25 mole% of the total concentration of zinc and chromium, and wherein at least three moles of ammonium per mole of chromium in said solution have been added to the solution;

(b) collecting the co-precipitated solid produced in (a);

(c) drying the collected solid; and

(d) calcining the dried solid.

16. The method of claim 15, wherein the ZnCr is₂O₄Generated during (d).