Patent Application
20240001356
The present invention relates to a process for treating a catalyst. In particular, the present invention relates to a process for treating a catalyst before it is unloaded.
The catalysts used in chemical reactions are essential materials for the production of many compounds, and have the main function of increasing the rate of the reactions. The catalysts are selected according to the reaction that is to be carried out.
In the field of the production of alkane or alkene compounds containing halogen atoms, the catalyst is generally used in gas phase. The catalyst may either be used in combination with a hydrogen halide, or give rise to a hydrogen halide during the implementation of a reaction. At the end of the implementation of the reaction, some of the hydrogen halide is present in the reactor and even absorbed or adsorbed by the catalyst itself. The presence of this hydrogen halide is particularly dangerous when there is a need to perform maintenance operations that necessitate the unloading of the catalyst.
It is therefore necessary to remove this hydrogen halide from the reactor and from the catalyst in order to guarantee the safety of intervening personnel during the unloading of the catalyst. The document EP 3 238 820 describes a process for unloading a catalyst implementing a step of high-temperature treatment. This high-temperature treatment step has a tendency to partially degrade the catalyst, and consumes a great deal of energy.
There is therefore a need for a catalyst unloading process that is safe, effective and inexpensive in terms of energy.
The present invention relates to a process for treating, in a reactor containing a catalytic bed, a solid catalyst, said process comprising the steps of:
The present process provides an economic and energetic saving since the inert gas flows through the catalytic bed at a temperature that is lower than the temperature of the catalytic reaction. In addition, by implementing step b) at a temperature T2 that is lower than the temperature T1 at which the catalytic reaction of step a) is implemented, the catalyst does not deteriorate, which enables subsequent use of the latter, optionally after regeneration, without a loss in activity. In the present process, the implementation of step b) is after, preferably subsequent to, the implementation of step a).
According to a preferred embodiment, the inert gas introduced into the reactor is at a temperature of between ambient temperature and the temperature T2. Preferably, the inert gas introduced into the reactor is at ambient temperature. The inert gas introduced will thus gradually cool the catalytic bed while removing the hydrogen halide residues present in the reactor and adsorbed or absorbed in the catalyst. The introduction of an inert gas having a temperature of ambient temperature or close to ambient temperature enables an additional energetic and economic saving.
According to a preferred embodiment, the hydrogen halide is hydrogen fluoride or hydrogen chloride.
According to a preferred embodiment, the temperature T2 decreases during the implementation of step b), preferably the temperature T2 decreases at a rate of less than 1° C./min during the implementation of step b).
According to a preferred embodiment, the inert gas flows at a flow rate of greater than 0.1 ml/min per ml of catalyst.
According to a preferred embodiment, the catalyst is based on carbon or based on a metal selected from the group consisting of Cr, Fe, Sb, Ni, Co, Zn, Al and Mn.
According to a preferred embodiment, step a) implements a gas-phase reaction between HF and a C1-C4 halohydrocarbon compound A or step a) implements a gas-phase dehydrohalogenation reaction of a saturated C1-C4 hydrocarbon compound B comprising at least one halogen atom to form an unsaturated C1-C4 hydrocarbon compound and a hydrogen halide.
According to a preferred embodiment, the compound A is selected from the group consisting of 1,1,2-trichloroethane, 2-chloro-1,1,1-trifluoroethane, 1-chloro-1,1,2-trifluoroethane, 1-chloro-1,2,2-trifluoroethane, 1,1,1,3,3,3-hexachlorodifluoropropane, 1,1,1,3,3,3-hexachloropropane, 1,1,1,3,3-pentachloropropane, 2,2,3-trichloro-1,1,1,3,3-pentafluoropropane, 1,1,1,3,3,3-hexachlorodifluoropropane, 1,1-dichloro-2,2,3,3,3-pentafluoropropane, 1,3-dichloro-1,2,2,3,3-pentafluoropropane, 1,1,1,2,3-pentachloropropane, 1,1,2,2,3-pentachloropropane, 1,1,1,3,3-pentachloropropane, 1,2-dichloroethylene, 1,1,2-trichloroethylene, 1,1,2,2-tetrachloroethylene, 1,1,2-trichloro-3,3,3-trifluoropropene, hexafluoropropene, 1,1,3,3,3-pentafluoropropene, 1,3,3,3-tetrafluoropropene, 2-chloro-3,3,3-trifluoropropene, 1,1,2,3-tetrachloropropene, 2,3,3,3-tetrachloropropene, 1-chloro-3,3,3-trifluoropropene, 1,1,3,3-tetrachloropropene, 1,3,3,3-tetrachloropropene, 2,3-dichloro-1,1,1-trifluoropropane, 2-chloro-1,1,1,2-tetrafluoropropane; or
According to a preferred embodiment, said process comprises a step c) of unloading the catalyst from said reactor.
According to a preferred embodiment, step b) comprises a step b1) of cooling the catalytic bed from the temperature T1 to T2, and then a step b2) of causing said inert gas to flow through the catalytic bed.
The present invention also relates to a process for treating, in a reactor containing a catalytic bed, a solid catalyst, said process comprising the steps of:
The present invention relates to a process for treating a catalyst. In particular, the present invention relates to a process for treating a solid catalyst. Thus, the present invention relates to a process for treating, in a reactor containing a catalytic bed, a solid catalyst.
Preferably, the present process comprises the steps of:
The process according to the present invention is typically conducted in a reactor provided with a fixed catalytic bed. The reactor and its associated feed lines, effluent lines and associated devices have to be constructed from materials which are resistant to hydrogen halides such as hydrogen fluoride or hydrogen chloride. Typical construction materials, well known in the state of the art of fluorination, include stainless steels, in particular of austenitic type, well-known alloys having a high nickel content, such as Monel© nickel/copper alloys, Hastelloy© nickel-based alloys and Inconel© nickel/chromium alloys.
According to a preferred embodiment, in step a) the hydrogen halide is in anhydrous form. Preferably, the compound A and the compound B described above can also be in anhydrous form.
According to a preferred embodiment, in step b) the inert gas is in anhydrous form.
The term anhydrous refers to a content by mass of water of less than 1000 ppm, advantageously 500 ppm, preferably of less than 200 ppm, in particular of less than 100 ppm, more particularly of less than 50 ppm and favorably of less than 25 ppm, in the compound under consideration.
Catalyst
According to a preferred embodiment, the catalyst is based on carbon or on a metal selected from the group consisting of Cr, Ti, Al, Mn, Ni, Co, Fe, Cu, Zn, Sn, Au, Ag, Pt, Pd, Ru, Rh, Mo, Zr, Ge, Nb, Ta, Ir, Hf, V, Mg, Li, Na, K, Ca, Cs, Ru and Sb; preferably, the catalyst is based on a metal selected from the group consisting of Cr, Fe, Sb, Ni, Co, Zn, Al et Mn. The carbon-based catalyst may be activated carbon, charcoal or graphite. The metal-based catalyst may be in the oxide, halide, or oxyhalide form of said metal. In particular, the catalyst is based on Cr, Al, Fe or Sb. The catalyst may be an antimony, iron or aluminum halide, such as SbCl5, FeCl3, or AlCl3. The catalyst may be a chromium oxide, a chromium oxyfluoride or a chromium fluoride. When the catalyst is based on chromium, it may contain a cocatalyst selected from the group consisting of Co, Zn, Mn, Ni or a mixture thereof, in a content by mass of from 1% to 10% based on the total weight of said catalyst.
Said catalyst may be a bulk or supported catalyst. The support may be selected from the group consisting of activated carbon, alumina and aluminum fluoride. For example, catalysts such as Cr2O3, MgF2, SbCl5 or FeCl3 may be supported on activated carbon.
Said catalyst may be activated before implementing the step a) detailed below. The catalyst may be activated according to the methods known to those skilled in the art. For example, the catalyst may be activated in the presence of oxygen, of HF or of nitrogen, or a mixture thereof, at a temperature of between 100° C. and 500° C.
Step a)
Said step a) comprises implementing, in said reactor, a gas-phase catalytic reaction at a catalytic bed temperature T1. Said catalytic reaction may either be implemented in the presence of a hydrogen halide or give rise to the formation of a hydrogen halide.
The hydrogen halide may be selected from the group consisting of HF, HCl, HBr and HI. Preferably, the hydrogen halide is hydrogen fluoride (HF) or hydrogen chloride (HCl).
According to a preferred embodiment, step a) may implement a gas-phase reaction between HF and a C1-C4 halohydrocarbon compound A. Preferably, step a) implements a reaction between hydrogen fluoride and a compound A to form a halohydrocarbon compound comprising at least one fluorine atom. Said compound A may be a saturated compound of the formula 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, C3Cl2F6, C3H2Cl6, C3H2BrCl5, C3H2Cl5F, C3Cl4F2, C3H2Cl3F3, C3H2Cl2F4, C3H2ClF5, C3H3Cl5, C3H3Cl4F, C3H3Cl3F2, C3H3Cl2F3, C3H3ClF4, C3H4Cl4, C4H4Cl4, C4H4Cl6, C4H6Cl6, C4H5Cl4F1 or C6H4Cl8, or an unsaturated compound of the formula C2Cl4, C2BrCl3, C2Cl3F, C2Cl2F2, C2ClF3, C2F4, C2HCl3, C2HBrCl2, C2HCl2F, C2HClF2, C2HF3, C2H2Cl2, C2H2ClF, C2H2F2, C2H3Cl, C2H3F, C2H4, C3H6, C3H5Cl, C3H4C2, C3H3Cl3, C3H2Cl4, C3HCl5, C3H2ClF3, C3F3HCl2, C3F2H2Cl2, C3F4H, ClC3Cl6, C3Cl5F, C3Cl4F2, C3Cl3F3, C3Cl2F4, C3ClF5, C3HF5, C3H2F4, C3F6, C4Cl8, C4Cl2F6, C4ClF7, C4H2F6, or C4HClF6.
Preferably, said compound A may be selected from the group consisting of 1,1,2-trichloroethane, 2-chloro-1,1,1-trifluoroethane, 1-chloro-1,1,2-trifluoroethane, 1-chloro-1,2,2-trifluoroethane, 1,1,1,3,3,3-hexachlorodifluoropropane, 1,1,1,3,3,3-hexachloropropane, 1,1,1,3,3-pentachloropropane, 2,2,3-trichloro-1,1,1,3,3-pentafluoropropane, 1,1,1,3,3,3-hexachlorodifluoropropane, 1,1-dichloro-2,2,3,3,3-pentafluoropropane, 1,3-dichloro-1,2,2,3,3-pentafluoropropane, 1,1,1,2,3-pentachloropropane, 1,1,2,2,3-pentachloropropane, 1,1,1,3,3-pentachloropropane, 1,2-dichloroethylene, 1,1,2-trichloroethylene, 1,1,2,2-tetrachloroethylene, 1,1,2-trichloro-3,3,3-trifluoropropene, hexafluoropropene, 1,1,3,3,3-pentafluoropropene, 1,3,3,3-tetrafluoropropene, 2-chloro-3,3,3-trifluoropropene, 1,1,2,3-tetrachloropropene, 2,3,3,3-tetrachloropropene, 1-chloro-3,3,3-trifluoropropene, 1,1,3,3-tetrachloropropene, 1,3,3,3-tetrachloropropene, 2,3-dichloro-1,1,1-trifluoropropane, 2-chloro-1,1,1,2-tetrafluoropropane.
More preferentially, said compound A may be selected from the group consisting of 1,1,2-trichloroethane, 2-chloro-1,1,1-trifluoroethane, 1-chloro-1,1,2-trifluoroethane, 1-chloro-1,2,2-trifluoroethane, 2-chloro-3,3,3-trifluoropropene, 1,1,1,2,3-pentachloropropane, 1,1,2,2,3-pentachloropropane, 1,1,2,3-tetrachloropropene, 2,3,3,3-tetrachloropropene, 1-chloro-3,3,3-trifluoropropene, 1,1,1,3,3-pentachloropropane, 1,1,3,3-tetrachloropropene, 1,3,3,3-tetrachloropropene, 2,3-dichloro-1,1,1-trifluoropropane, 2-chloro-1,1,1,2-tetrafluoropropane, or mixtures thereof.
In particular, specific examples of reaction between HF and the compound A include the conversion of 1,1,2-trichloroethane (CHCl2CH2Cl or HCC-140) into 1-chloro-2,2-difluoroethane (CH2ClCF2H or HCFC-142), the conversion of 1,1,1,3,3,3-hexachlorodifluoropropane (CCl3CF2CCl3 or CFC-212ca) into a mixture of 1,1,3-trichloro-1,2,2,3,3-pentafluoropropane (CCl2FCF2CClF2 or CFC-215ca) and 1,3-dichloro-1,1,2,2,3,3-hexafluoropropane (CClF2CF2CClF2 or CFC-216ca), the conversion of 1,1,1,3,3,3-hexachloropropane (CCl3CH2CCl3 or HCC-230fa) into 1-chloro-1,1,3,3,3-pentafluoropropane (CF3CH2CClF2 or HCFC-235fa) and 1,1,1,3,3,3-hexafluoropropane (CF3CH2CF3 or HFC-236fa), the conversion of 1,1,1,3,3-pentachloropropane (CCl3CH2CHCl2 or HCC-240fa) into a mixture of 1,1,1,3,3-pentafluoropropane (CHF2CH2CF3 or HFC-245fa), 1-chloro-3,3,3-trifluoro-1-propene (CHCl═CHCF3 or HCFO-1233zd) and 1,3,3,3-tetrafluoropropene (CHF═CHCF3 or HFO-1234ze), the conversion of 2,2,3-trichloro-1,1,1,3,3-pentafluoropropane (CF3CCl2CClF2 or CFC-215aa) into a mixture of 1,1,1,3,3,3-hexachlorodifluoropropane (CF3CCl2CF3 or CFC-212ca) and 2-chloro-1,1,1,2,3,3,3-heptafluoropropane (CF3CClFCF3 or CFC-217ba), the conversion of 1,1,1,3,3,3-hexachlorodifluoropropane (CF3CCl2CF3 or CFC-212ca) into 2-chloro-1,1,1,2,3,3,3-heptafluoropropane (CF3ClFCF3 or CFC-217ba), the conversion of a mixture containing 1,1-dichloro-2,2,3,3,3-pentafluoropropane (CF3CF2CHCl2 or HCFC-225ca) and 1,3-dichloro-1,2,2,3,3-pentafluoropropane (CClF2CF2CHClF or HCFC-225cb) into a mixture of 1-chloro-1,2,2,3,3,3-hexafluoropropane (CF3CF2CHClF or HCFC-226ca) and 1,1,1,2,2,3,3-heptafluoropropane (CF3CF2CHF2 or HFC-227ca), the conversion of 1,1,1,2,3-pentachloropropane (CCl3CHClCH2Cl or HCC-240db) into 2-chloro-3,3,3-trifluoro-1-propene (CF3CCl═CH2 or HCFO-1233xf), the conversion of 1,1,2,2,3-pentachloropropane (CHCl2CCl2CH2Cl or HCC-240aa) into 2-chloro-3,3,3-trifluoro-1-propene (CF3CCl═CH2 or HCFO-1233xf), the conversion of 1,1,1,2,3-pentachloropropane (CCl3CHClCH2Cl or HCC-240db) into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of 1,1,2,2,3-pentachloropropane (CHCl2CCl2CH2Cl or HCC-240aa) into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of 1,1,1,3,3-pentachloropropane (CCl3CH2CHCl2 or HCC-240fa) into 1,3,3,3-tetrafluoropropene (CF3CH═CHF or HFO-1234ze), the conversion of 1,2-dichloroethylene (CHCl═CClH or HCO-1130) into 1-chloro-2,2-difluoroethane (CH2ClCF2H or HCFC-142)2, the conversion of 1,1,2-trichloro-3,3,3-trifluoro-1-propene (CCl2═CClCF3 or CFC-1213xa) into a mixture of 2,3-dichloro-1,1,1,3,3-pentafluoropropane (CF3CHClCClF2 or HCFC-225da), of 2-chloro-1,1,1,3,3,3-hexafluoropropane (CF3CHClCF3 or HCFC-226da) and/or of 2-chloro-1,1,3,3,3-pentafluoro-1-propene (CF3CCl═CF2 or CFC-1215xc), the conversion of hexafluoropropene (CF3CF═CF2 or CFC-1216yc) into 1,1,1,2,3,3,3-heptafluoropropane (CF3CHFCF3 or HFC-227ea), the conversion of 1,1,3,3,3-pentafluoropropene (CF3CH═CF2 or HFO-1225zc) into 1,1,1,3,3,3-hexafluoropropane (CF3CH2CF3 or HFC-236fa), the conversion of 1,3,3,3-tetrafluoropropene (CF3CH═CHF or HFO-1234ze) into 1,1,1,3,3-pentafluoropropane (CF3CH2CHF2 or HFC-245fa), the conversion of 2-chloro-3,3,3-trifluoro-1-propene (CF3CCl═CH2 or HCFO-1233xf) into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of 1,1,2,3-tetrachloro-1-propene (CCl2═CClCH2Cl or HCO-1230xa) into 2-chloro-3,3,3-trifluoro-1-propene (CF3CCl═CH2 or HCFO-1233xf) or 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of 2,3,3,3-tetrachloro-1-propene (CCl3CCl═CH2 or HCO-1230xf) into 2-chloro-3,3,3-trifluoro-1-propene (CF3CCl═CH2 or HCFO-1233xf) or into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of 1-chloro-3,3,3-trifluoro-1-propene (CF3CH═CHCl or HCFO-1233zd) or of 1,1,3,3-tetrachloro-1-propene (CCl2═CHCHCl2 or HCO-1230za) or of 1,3,3,3-tetrachloroprop-1-ene (CCl3CH═CHCl or HCO-1230zd) into 1,3,3,3-tetrafluoropropene (CF3CH═CHF or HFO-1234ze), the conversion of 2,3-dichloro-1,1,1-trifluoropropane (CF3CHClCH2Cl or HCFC-243db) into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of 2-chloro-1,1,1,2-tetrafluoropropane (CF3CFClCH3 or HCFC-244bb) into 1,1,1,2,2-pentafluoropropane (CF3CF2CH3 or HFC-245cb), the conversion of 1,1,2,2-tetrachloroethylene (Cl2C═CCl2 or PER) into 1,1,1,2,2-pentafluoroethane (CF3CF2H or HFC-125), the conversion of 2-chloro-1,1,1-trifluoroethane (CF3CH2Cl or R-133a) into 1,1,1,2-tetrafluoroethane (CF3CCH2F or R-134a), the conversion of 1,1,2,2-tetrachloroethylene (Cl2C═CCl2 or PER) into 1,1,1,2-tetrafluoroethane (CF3CCH2F or R-134a), the conversion of 1,1,2-trichloroethylene (ClHC═CCl2) into 1,1,1,2-tetrafluoroethane (CF3CCH2F or R-134a) and/or 1,1,1,2,2-pentafluoroethane (CF3CF2H or HFC-125).
More particularly, specific examples of fluorination reactions of compounds A include the conversion of 1,1,1,2,3-pentachloropropane (CCl3CHClCH2Cl or HCC-240db) into 2-chloro-3,3,3-trifluoro-1-propene (CF3CCl═CH2 or HCFO-1233xf), the conversion of 1,1,2,2,3-pentachloropropane (CHCl2CCl2CH2Cl or HCC-240aa) into 2-chloro-3,3,3-trifluoro-1-propene (CF3CCl═CH2 or HCFO-1233xf), the conversion of 1,1,1,2,3-pentachloropropane (CCl3CHClCH2Cl or HCC-240db) into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of 1,1,2,2,3-pentachloropropane (CHCl2CCl2CH2Cl or HCC-240aa) into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of 1,1,1,3,3-pentachloropropane (CCl3CH2CHCl2 or HCC-240fa) into 1,3,3,3-tetrafluoropropene (CF3CH═CHF or HFO-1234ze), the conversion of 1,1,2-trichloroethane (CHCl2CH2Cl or HCC-140) into 1-chloro-2,2-difluoroethane (CH2ClCF2H or HCFC-142), the conversion of 2-chloro-3,3,3-trifluoro-1-propene (CF3CCl═CH2 or HCFO-1233xf) into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of 1,1,2,3-tetrachloro-1-propene (CCl2═CClCH2Cl or HCO-1230xa) into 2-chloro-3,3,3-trifluoro-1-propene (CF3CCl═CH2 or HCFO-1233xf) or into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of 2,3,3,3-tetrachloro-1-propene (CCl3Cl═CH2 or HCO-1230xf) into 2-chloro-3,3,3-trifluoro-1-propene (CF3CCl═CH2 or HCFO-1233xf) or into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of 1-chloro-3,3,3-trifluoro-1-propene (CF3CH═CHCl or HCFO-1233zd) or of 1,1,3,3-tetrachloro-1-propene (CCl2═CHCHCl2 or HCO-1230za) or of 1,3,3,3-tetrachloroprop-1-ene (CCl3CH═CHCl or HCO-1230zd) into 1,3,3,3-tetrafluoropropene (CF3CH═CHF or HFO-1234ze), the conversion of 1,2-dichloroethylene (CHCl═CClH or HCO-1130) into 1-chloro-2,2-difluoroethane (CH2ClCF2H or HCFC-142), the conversion of 2,3-dichloro-1,1,1-trifluoropropane (CF3CHClCH2Cl or HCFC-243db) into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of 2-chloro-1,1,1,2-tetrafluoropropane (CF3CFClCH3 or HCFC-244bb) into 1,1,1,2,2-pentafluoropropane (CF3CF2CH3 or HFC-245cb), the conversion of 1,1,2,2-tetrachloroethylene (Cl2C═CCl2 or PER) into 1,1,1,2,2-pentafluoroethane (CF3CF2H or HFC-125), the conversion of 2-chloro-1,1,1-trifluoroethane (CF3CH2Cl or R-133a) into 1,1,1,2-tetrafluoroethane (CF3CCH2F or R-134a), the conversion of 1,1,2,2-tetrachloroethylene (Cl2C═CCl2 or PER) into 1,1,1,2-tetrafluoroethane (CF3CCH2F or R-134a), the conversion of 1,1,2-trichloroethylene (ClHC═CCl2) into 1,1,1,2-tetrafluoroethane (CF3CCH2F or R-134a) and/or 1,1,1,2,2-pentafluoroethane (CF3CF2H or HFC-125).
According to another preferred embodiment, step a) may implement a gas-phase dehydrohalogenation reaction of a saturated C1-C4 hydrocarbon compound B comprising at least one halogen atom to form an unsaturated C1-C4 hydrocarbon compound and a hydrogen halide. Preferably, the compound B is selected from the group consisting of 1,1-difluoroethane, 1,1,1-trifluoroethane, 2-chloro-1,1,1-trifluoroethane, 1,1,1,2-tetrafluoroethane, 1,1,2,2-tetrafluoroethane, 1,1,1,2,2-pentafluoroethane, 1,1,1,2-tetrafluoropropane, 1,1,1,3,3-pentafluoropropane, 1,1,1,2,3,3-hexafluoropropane, 1,1,1,3,3,3-hexafluoropropane, 1,1,1,2,2,3-hexafluoropropane, 1,1,1,2,2-pentafluoropropane, 1,1,1,2,3-pentafluoropropane, 2,3-dichloro-1,1,1-trifluoropropane and 2-chloro-1,1,1,2-tetrafluoropropane. In particular, the compound B is selected from the group consisting of 1,1,1,2,2-pentafluoropropane, 1,1,1,3,3-pentafluoropropane, 2,3-dichloro-1,1,1-trifluoropropane and 2-chloro-1,1,1,2-tetrafluoropropane. Preferably, the hydrogen halide is HF or HCl.
Specific examples of gas-phase dehydrohalogenation of the compound B include the conversion of 1,1-difluoroethane (CHF2CH3 or HFC-152a) into vinyl chloride (CHF═CH2 or HFO-1141), the conversion of 1,1,1-trifluoroethane (CF3CH3 or HFC-143a) into vinylidene fluoride (CF2═CH2 or HFO-1132a), the conversion of 2-chloro-1,1,1-trifluoroethane (CF3CH2Cl or HCFC-133a) into 2-chloro-1,1-difluoroethylene (CF2═CHCl or HCFO-1122), the conversion of 1,1,1,2-tetrafluoroethane (CF3CH2F or HFC-134a) into trifluoroethylene (CF2═CHF or HFO-1123), the conversion of 1,1,2,2-tetrafluoroethane (CHF2CHF2 or HFC-134) into trifluoroethylene (CF2═CHF or HFO-1123), the conversion of 1,1,1,2-tetrafluoropropane (CH3CHFCF3 or HFC-254eb) into 1,1,1-trifluoropropene (CH2═CHCF3 or HFO-1243zf), the conversion of 1,1,1,3,3-pentafluoropropane (CHF2CH2CF3 or HFC-245fa) into 1,3,3,3-tetrafluoropropene (CHF═CHCF3 or HFO-1234ze), the conversion of 1,1,1,2,3,3-hexafluoropropane (CHF2CHFCF3 or HFC-236ea) into 1,2,3,3,3-pentafluoropropene (CHF═CFCF3 or HFO-1225ye), the conversion of 1,1,1,3,3,3-hexafluoropropane (CF3CH2CF3 or HFC-236fa) into 1,1,3,3,3-pentafluoropropene (CF3CH═CF2 or HFO-1225zc), the conversion of 1,1,1,2,2,3-hexafluoropropane (CF3CF2CFH2 or HFC-236cb) into 1,2,3,3,3-pentafluoropropene (CHF═CFCF3 or HFO-1225ye), the conversion of 1,1,1,2,2-pentafluoropropane (CF3CF2CH3 or HFC-245cb) into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf) and the conversion of 1,1,1,2,3-pentafluoropropane (CF3CHFCH2F or HFC-245eb) into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf), the conversion of (CF3CHClCH2Cl or HCFC-243db) into 2-chloro-3,3,3-trifluoro-1-propene (CF3CCl═CH2 or HCFO-1233xf), the conversion of 2-chloro-1,1,1,2-tetrafluoropropane (CF3CFClCH3 or HCFC-244bb) into 2,3,3,3-tetrafluoropropene (CF3CF═CH2 or HFO-1234yf).
The catalytic bed temperature T1 may be between 100° C. and 500° C., advantageously between 150° C. and 450° C., preferably between 200° C. and 400° C., more preferentially between 250° C. and 380° C.
Step a) may also be implemented according to the following operating conditions:
Those skilled in the art will adapt the operating conditions above according to the reaction to be carried out in step a).
Step a) may be implemented over a duration of between 2000 and 25 000 h, preferably between 2500 and 24 000 h, more preferentially between 3000 and 20 000 h.
An oxidant, such as oxygen or chlorine, may be added during step a). The molar ratio of the oxidant to the compound A or B may be between 0.005 and 2, preferably between 0.01 and 1.5. The oxidant may be pure oxygen, air or a mixture of oxygen and nitrogen.
Step a) may optionally comprise a step of regeneration of the catalyst in alternation with said catalytic reaction. The regeneration step is generally implemented in the presence of a stream comprising oxygen at a temperature of between 100° C. and 500° C.
At the end of the implementation of step a), the catalyst is subjected to step b) according to the process of the present invention.
Step b)
According to the present process, step b) comprises causing an inert gas to flow through the catalytic bed. Preferably, step b) is implemented at a catalytic bed temperature T2 that is lower than T1. Thus, it is not necessary to heat the catalytic bed to remove the hydrogen halide present in the reactor or the catalyst. In order to maximize the removal of the hydrogen halide, the catalytic bed temperature T2 is greater than 30° C. Thus, at the start of implementation of step b), the temperature T2 is greater than 30° C.
After the implementation of step a), the stream of reactants is stopped, the temperature of the catalytic bed decreases from the temperature T1 to the temperature T2, which is lower than T1, and the inert gas is introduced into the reactor.
Preferably, the catalytic bed temperature T2 is greater than 40° C., advantageously greater than 50° C., preferably greater than 60° C., more preferentially greater than 70° C., in particular greater than 80° C., more particularly greater than 90° C., favorably greater than 100° C.
Preferably, the catalytic bed temperature T2 is lower than 380° C., advantageously lower than 360° C., preferably lower than 340° C., more preferentially lower than 320° C., in particular lower than 300° C., favorably lower than 250° C.
According to a preferred embodiment, the inert gas is introduced into the reactor at a temperature of between ambient temperature and T2, advantageously of between ambient temperature and 50° C., and in particular the inert gas is introduced into the reactor at ambient temperature.
The passage of the inert gas through the catalytic bed leads to a decrease in the catalytic bed temperature T2 during the implementation of step b). Preferably, the temperature T2 decreases at a rate of less than 5° C./min during the implementation of step b), in particular of less than 1° C./min, during the implementation of step b).
According to a preferred embodiment, the inert gas flows at a flow rate of greater than 0.1 ml/min per ml of catalyst, advantageously of greater than 0.2 ml/min per ml of catalyst, preferably of greater than 0.3 ml/min per ml of catalyst, more preferentially of greater than 0.4 ml/min per ml of catalyst, in particular of greater than 0.5 ml/min per ml of catalyst, favorably of greater than 0.6 ml/min per ml of catalyst, advantageously favorably of greater than 0.7 ml/min per ml of catalyst, preferentially favorably of greater than 0.8 ml/min per ml of catalyst, particularly favorably of greater than 0.9 ml/min per ml of catalyst.
According to a preferred embodiment, step b) comprises a step b1) of cooling the catalytic bed from the temperature T1 to T2, and then a step b2) of causing said inert gas to flow through the catalytic bed.
Preferably, the inert gas is nitrogen or argon. In particular nitrogen.
Preferably, at the outlet of the reactor, the inert gas contains a content by mass of CO and CO2 of less than 100 ppm.
The apparatus used comprises a tubular reactor made from INCONEL© 600 (internal diameter of 28 mm−length=600 mm), placed vertically in an electric tube furnace. The reactor is equipped with indicators for pressure and temperature (movable thermocouple in an Inconel sleeve placed coaxially at the center of the tube). The fixed catalytic bed consists of a lower layer of corundum followed by a 180 ml layer of catalyst and an upper layer of corundum. The catalyst used is an Ni—Cr/AlF3 catalyst. Before use, it is dried and then activated in the presence of a mixture of hydrofluoric acid and nitrogen, at a temperature of between T=320° C. and T=350° C.
The characteristics of the catalyst after activation are as follows:
The reactants are introduced continuously at the upper end of the reactor and preheated to the furnace temperature through the upper layer of corundum, the gaseous products of the reaction exit at the lower end of the reactor through a pressure-regulating valve; the gas stream exiting from the valve is analyzed by gas chromatography.
Test 1 (Invention)
The reaction is conducted at atmospheric pressure and at a temperature of T=350° C. by continuously supplying anhydrous HF (137.6 g·h−1) and perchloroethylene (28.3 g·h−1). The GHSV (gas hourly space velocity) is 2000 h−1. The HF:organic molar ratio is 40.3.
After 19 h of reaction, the composition of the organic stream exiting the reactor is given in table 1 below.
After 98 h of reaction, the introduction of the reactants and the heating of the electric furnace are stopped. Nitrogen is introduced into the reactor at a flow rate of 10 l·h−1 (0.9 ml·min−1 per ml of catalyst).
After flushing for 17 h, the temperature in the reactor is T=140° C. (i.e. a decrease at an average rate of 12° C. per hour).
Test 2 (Comparative)
A test identical to test 1 (same batch of activated catalyst) is carried out until the stopping of the reactants. After 98 h of reaction, the introduction of the reactants is stopped and the heating of the electric furnace is increased until a temperature of 360° C. is reached. Nitrogen is introduced into the reactor at a flow rate of 10 l·h−1 (0.9 ml·min−1 per ml of catalyst). The temperature of the furnace is maintained at a temperature of T=360° C. for 8 hours.
The catalyst of test 1 and the catalyst of test 2 are regenerated in identical fashion at atmospheric pressure, by treatment in air (1.5 l·h−1) at a temperature of T=350° C. for 72 hours.
After regeneration, the catalysts are analyzed (table 2).
The catalysts of test 1 and of test 2 thus regenerated are tested in the fluorination reaction of perchloroethylene. The reaction is conducted at atmospheric pressure and at a temperature of T=350° C. by continuously supplying anhydrous HF (137.6 g·h−1) and perchloroethylene (28.3 g·h−1). The GHSV (gas hourly space velocity) is 2000 h−1. The HF:organic molar ratio is 40.3. The analysis of the composition of the organic stream exiting the reactor is also conducted after 19 h and 43 h of reaction. The comparative results are presented in table 3 below.
These results clearly show that the treatment conducted on the catalyst of test 2 is harmful to it (lower BET surface area and catalytic activity). In contrast, the nitrogen treatment conducted on the catalyst of the test 1 makes it possible to obtain a better catalytic activity thereof after regeneration. Step b) according to the present invention makes it possible to avoid the premature degradation of the catalyst and to thus obtain a catalyst that is more effective later on when it is reused, for example after regeneration.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012271 | Nov 2020 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2021/052079 | 11/24/2021 | WO |
