JP5270361B2 - Method for producing fluorinated organic compound - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION (1) Field of the Invention The present invention relates to a novel method for producing a fluorinated organic compound, and more particularly to a method for producing a fluorinated olefin.

(2) Description of Related Art Hydrofluorocarbons (HFC), particularly tetrafluoropropenes (2,3,3,3-tetrafluoro-1-propene (HFO-1234yf) and 1,3,3,3-tetrafluoro- Hydrofluoroalkenes such as 1-propene (including HFO-1234ze) are refrigerants, extinguishing agents, heat transfer media, propellants, foaming agents, foaming agents, gaseous dielectrics, sterilant carriers, polymerization media, particle removal It is disclosed to be effective as a working fluid, carrier fluid, buffing abrasive, displacement desiccant and power cycle working fluid. Unlike chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), which can destroy the Earth's ozone layer, HFC does not contain chlorine and therefore does not threaten the ozone layer.

  Several methods for producing hydrofluoroalkanes are known. For example, US Pat. No. 4,900,874 (according to Ihara et al.) Describes a process for producing fluorine-containing olefins by contacting hydrogen gas with fluorinated alcohols. While this method appears to be a relatively high yield process, it raises safety concerns for handling hydrogen gas at high temperatures for manufacturing on a commercial scale. Furthermore, the cost of producing hydrogen gas is often very high due to construction of a hydrogen plant on site.

  US Pat. No. 2,931,840 (by Marquis) describes a process for producing fluorine-containing olefins by pyrolysis of methyl chloride and tetrafluoroethylene or chlorodifluoromethane. This method is a relatively low yield process in which organic starting materials are converted to unwanted and / or unimportant by-products in a significant proportion, such as a fairly large amount of carbon black. This carbon black is not only unnecessary, but also tends to deactivate the catalyst used in this process.

  There is a description about preparing R-1234yf from trifluoroacetylacetone and sulfur tetrafluoride. Banks et al., Journal of Fluorine Chemistry, Vol. 82, Iss. 2, p. 171-174 (1997). US Pat. No. 5,162,594 (by Krespan) discloses a process for producing a polyfluoroolefin product by reacting tetrafluoroethylene with another fluorinated ethylene in the liquid phase.

SUMMARY OF THE INVENTION Applicants have discovered a method for producing fluorinated organic compounds such as hydrofluoropropene. In one broad aspect of the invention, the method includes converting a halogenated alkane, preferably a fluorinated alkane, to a fluorinated alkene having an unsaturated terminal carbon with a halogen substituent, preferably a fluorine substituent. . In certain preferred embodiments, the method comprises at least one formula (I):
CF ₃ [C (R ¹ _a R ² _b )] _n C (R ³ _c R ⁴ _d ) (I)
A compound of at least one formula (II):
CF ₃ [C (R ¹ _a R ² _b )] _n−1 CZ═CHZ (II)
Including conversion to:
Wherein R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom or a halogen selected from the group consisting of fluorine, chlorine, bromine and iodine, provided that R ¹ , R ² , At least one of R ³ and R ⁴ is halogen; a and b are independently equal to 0, 1 or 2 (where (a + b) = 2); b and c are independently 0, 1, 2, Or is equal to 3 and (c + d) = 3; n is 1, 2, 3 or 4; and Z is each independently H or halogen (preferably F), provided that Z at the terminal carbon is halogen Preferably, Z at the terminal carbon is F.

  In certain preferred embodiments, each Z is different, and in particularly preferred embodiments, each Z is different and Z at the terminal carbon is F, ie, this compound is the embodiment when n is 1 (HFO-1234ze) including.

In certain embodiments, it is also preferred that the compound of formula (I) comprises a compound wherein each of R ¹ and R ² is H and at least one of R ³ or R ⁴ is H. In certain embodiments where the compound of formula I is a compound of three carbon atoms, the formula (IA):
_{CF 3 CH 2 CH m X 3} -m (IA)
Wherein X is independently F, Cl, I or Br; Z in formula (II) is each independently H or halogen (preferably F); and m is 1 or 2 It is. Preferred compounds used according to formula (IA) include pentachloropropane (HCC-240); tetrachlorofluoropropane (HCFC-241); trichlorodifluoropropane (HCFC-242); dichlorotrifluoropropane (HCFC-243); chloro Trifluoropropane (HCFC-244); and pentafluoropropane (HFC-245), including all their respective isomers, preferably HCFC-244fa and HFC-245fa.

  A preferred conversion step of the present invention catalyzes a compound of formula (I), preferably a compound of formula (IA), to one or more compounds of formula (II) in the gas phase or liquid phase (or combinations thereof). Including conversion. In a preferred embodiment, the catalytic conversion step comprises introducing the compound of formula (I) into the reaction system under conditions that effectively convert (the conversion of the compound of formula (I) is preferably At least about 50%, more preferably at least about 70%, even more preferably at least about 90%). In the conversion step, the selectivity to the compound of formula (II), preferably tetrafluoropropene, more preferably HFO-1234ze, is at least about 60%, more preferably at least about 80%, even more preferably at least about 95. It is also generally preferred to produce reaction products that are%.

Detailed Description of the Preferred Embodiment One beneficial aspect of the present invention is that the desired fluoroolefin, preferably C3 fluoroolefin, can be produced using a relatively high conversion and high selectivity reaction. Furthermore, the process in certain preferred embodiments can produce the desired fluoroolefin from relatively attractive starting materials. For example, in certain embodiments, compounds of formula (I) that may be advantageous starting materials include pentafluoropropene (particularly 1,1,3,3,3-pentafluoropropane (HFC-245fa)), or chlorotetra Fluoropropane (especially 1-chloro-1,3,3,3-tetrafluoropropane (HCFC-244fa)). For example, these products are relatively easy to handle, generally readily available in commercial quantities, or could be easily manufactured from other readily available ingredients. .

  The compound of formula (I) is preferably exposed to reaction conditions that effectively produce a reaction product containing one or more desired fluoroolefins, preferably one or more compounds of formula (II). . In one preferred aspect of the invention, the conversion step includes, for convenience, a reaction sometimes referred to herein as a dehydrohalogenation reaction, or in certain embodiments, particularly a dehydrofluorination reaction, which is not necessarily It is not intended to be limiting. Certain preferred embodiments of the present invention are described below, together with headings used for convenience, which are not necessarily intended to be limiting.

I. Formation of Compounds of Formula II In certain preferred embodiments, the conversion step is carried out under conditions that effectively convert at least about 40%, preferably at least about 55%, more preferably at least about 70% of Formula (I). Done. In certain preferred embodiments, the conversion is at least about 90%, more preferably about 100%. In some further preferred embodiments, the conversion of the compound of formula (I) to produce the compound of formula (II) is at least about 85%, preferably at least about 90%, more preferably at least about 95%, even more preferably. Is carried out under conditions that effectively obtain formula (II) with a selectivity of about 100%.

  Preferred reaction steps include gas phase reactions (or in some cases a combination of gas phase and liquid phase reactions) and it is believed that this reaction can be carried out batchwise, continuously, or a combination thereof.

A. Gas Phase Dehydrohalogenation Reaction One very preferred reaction step according to the present invention comprises one of the compounds of formula (IB) when m is 1, ie formula (IB):
CF ₃ CH ₂ CHX ₂ (IB)
This can be explained by the reaction when the compound is contained.

  For example, one preferred compound of formula (IB) is chlorotetrafluoropropane, especially 1-chloro-1,3,3,3-tetrafluoropropane (244fa). In certain preferred embodiments, the stream comprising a compound of formula (I), preferably a compound of (IA) and / or (IB), is preheated to a temperature of about 150 ° C. to about 300 ° C., preferably about 250 ° C. Later, it is introduced into a reaction vessel maintained at the desired temperature, preferably from about 400 ° C to about 700 ° C, more preferably from about 450 ° C to about 600 ° C.

  The container is preferably made of a corrosion-resistant material such as Hastelloy, Inconel, Monel and / or fluororesin lining. This vessel preferably contains a fixed or fluidized catalyst bed packed with a catalyst, for example a suitable dehydrohalogenated catalyst, and is equipped with suitable means for heating the reaction mixture to the desired reaction temperature.

  Thus, in view of all the teachings contained herein, it is believed that this dehydrohalogenation reaction step can be performed using a wide variety of process parameters and process conditions. However, in certain embodiments, it is preferred that this reaction step comprises a gas phase reaction, preferably in the presence of a catalyst.

Although it is believed that a wide variety of catalysts and catalyst types can be used in accordance with the present invention, Applicants have discovered that excellent results are obtained when the catalyst comprises a charge neutral metal catalyst. As used herein, the term “charge neutral metal catalyst” means a catalyst containing a metal atom having a substantially neutral charge. For convenience, we refer to these charge neutral metal catalysts herein as “M ⁰ ” or “M ⁰ catalyst”. Similar designations are used for catalysts containing specific metals. For example, a catalyst containing substantially neutral nickel atoms is referred to as “Ni ⁰ catalyst”. In certain preferred embodiments, the present conversion method, carbon-based catalyst and / or metal-based catalyst, preferably includes providing a M ⁰ catalyst (supported or non-supported system). When used, the M ⁰ catalyst preferably includes a Ni ⁰ catalyst, or a Pd ⁰ catalyst, an Fe ⁰ catalyst, and combinations thereof. In certain preferred embodiments, the catalyst consists essentially of ^{M 0} catalyst, preferably Ni ⁰ catalyst, Pd ⁰ catalyst, Fe ⁰ catalyst, and ^{M 0} catalyst selected from the group consisting of two or more of these . When these catalysts are supported Catellus, in certain embodiments it is preferred that the support is carbon and / or activated carbon. Of course, it is contemplated that other catalysts and catalyst supports such as palladium on carbon, palladium-based catalysts (such as palladium on aluminum oxide) can be used, and many other catalysts are considered in view of the teachings contained herein. It is anticipated that it can be used on demand for certain aspects. In addition to any two or more of the catalysts listed here, other catalysts not listed in this specification can also be used in combination.

Ni-based supported catalyst, preferably a Ni ^0- based catalyst (compound of formula (I) comprises one or more compounds of formula (IA) and / or compounds of formula (IB), or consists essentially of one or more compounds For the compounds of formula (IA) and / or preferred in many embodiments, including many embodiments consisting of compounds of formula (IB), first the Ni (II) acetylacetonate precursor and tetrabutylammonium bromide together In general, it is generally preferred to first form the catalyst and then subject it to reducing conditions (eg, to hydrogen) to convert Ni (II) to Ni (0). Further, it is generally preferred that the catalyst is dried before use and subjected to a fluorination treatment. One suitable method of forming a preferred catalyst of this type is disclosed in the examples herein.

  Activated carbon catalyst (compound of formula (I) comprises one or more compounds of formula (IA) and / or (IB) or consists essentially of one or more compounds of formula (IA) and / or ( For many embodiments, including many embodiments comprising compounds of IB), it is generally preferred to subject the activated carbon to drying and fluorination treatment prior to use. One suitable method of forming a preferred catalyst of this type is disclosed in the examples herein.

  In general, the catalyst, especially the activated carbon catalyst, is preferably fluorinated, preferably for several hours (eg, 6 hours). In a preferred embodiment, the fluorination of the catalyst is performed by exposing the catalyst to a stream of HF at about the reaction temperature and a slight pressure (eg, about 35 psia).

  The gas phase dehydrohalogenation reaction can be carried out, for example, by introducing a gaseous compound of formula (I), preferably (IA), into a suitable reaction vessel or reactor. The container is preferably made of a corrosion-resistant material such as Hastelloy, Inconel, Monel and / or fluororesin lining. This vessel comprises a fixed or fluidized catalyst bed packed with a catalyst, preferably as described herein, for example a suitable dehydrohalogenated catalyst, for heating the reaction mixture to the desired reaction temperature. Those equipped with suitable means are preferred.

  It will be appreciated that a wide variety of reaction temperatures may be used, depending on relevant factors such as the catalyst used and the most desired reaction product, but particularly includes compounds of formula (I) (preferably essentially of formula ( The reaction temperature of the dehydrohalogenation step (comprising the compound of IA) and / or the compound of formula (IB) is generally about 400 ° C. to about 800 ° C., preferably about 400 ° C. to about 700 ° C. Is preferred.

  In general, it will be appreciated that a wide variety of reaction pressures may be used, depending on related factors such as the particular catalyst used and the most desired reaction product. Examples of the reaction pressure include atmospheric pressure or higher, atmospheric pressure, or reduced pressure, and in a specific preferable embodiment, the reaction pressure is about 1 to about 120 psia.

  In certain embodiments, an inert diluent gas such as nitrogen can be used with other reactor feed materials. When using such a diluent, it is generally preferred that the compound of formula (I) be greater than about 50% to over 99%, based on the combined weight of the diluent and the compound of formula (I).

  The amount of catalyst used will vary depending on the specific parameters present in each embodiment. In certain preferred embodiments, the contact time is from about 0.1 seconds to about 1000 seconds, preferably from about 3 seconds to about 50 seconds.

The compound of formula (I) comprises a compound of formula (1B) and / or a compound of formula I (B) or consists essentially of a compound of formula (1B) and / or a compound of formula I (B); and, in particular embodiments the product of the desired formula (II) is HFO-1234ze, Applicants have as a catalyst, M ⁰ catalyst, preferably substantially, such as palladium on carbon catalyst and carbon supported nickel catalyst In particular, it has been found preferable to use a catalyst containing neutral palladium, nickel, iron and / or carbon.

  In such dehydrofluorination embodiments described in this section, the conversion of the compound of formula (I) should be at least about 50%, preferably at least about 65%, more preferably at least about 90%. preferable. In these embodiments, the selectivity to HFO-1234ze is preferably at least about 70%, preferably at least about 80%, more preferably at least about 95%.

B. Liquid Phase Reduction One possible reaction step includes the compound of formula (I) (eg 1-chloro-1,3,3,3-tetrafluoropropane (HCFC-244fa)) with potassium hydroxide (KOH). And the like to form a compound of formula (II) upon contact with a dehydrohalogenating agent such as This reaction is illustrated by the following reaction equation, which is for purposes of illustration and not limitation.

CF ₃ CH ₂ CHFCl + KOH → CF ₃ CH═CHF + KCl + H ₂ O
In a preferred aspect of such embodiments, a phase transfer agent such as crown-18-ether is included in the reaction mixture, and preferably KOH is from about 10% to about 50%, preferably from about 20% to about 30%. Add as a wt% aqueous KOH solution.

  In certain preferred embodiments, the KOH solution is introduced into the reaction vessel at a relatively low temperature, preferably about -10 ° C to about 10 ° C, more preferably about 0 ° C. Thereafter, an appropriate amount of the compound of formula (I), preferably about 0.1 to about 100 mol, more preferably 0.9 to about 10 mol, per 1 mol of KOH is added to the reaction vessel. The reaction mixture is gradually heated to about 40 ° C. to about 80 ° C., preferably about 50 ° C. to about 60 ° C., preferably with the addition of kinetic energy (stirring). Since the preferred reaction is an exothermic reaction, the temperature of the reaction mixture may be raised to a temperature of about 60 ° C to about 95 ° C, preferably about 65 ° C to about 75 ° C. The reaction pressure in these embodiments varies depending on the particular process parameters applied to each, but in certain embodiments varies from about 0 to about 200 psig during the reaction. In certain embodiments, the reaction exotherm is removed from the reaction mixture (such as by cooling) so as to maintain the reaction temperature within the range indicated above. In certain preferred embodiments, the total reaction time is about 1 to about 40 hours, preferably about 1 to about 10 hours, more preferably about 2 to about 6 hours.

  After the specified reaction time, it is preferred that the reaction mixture be cooled to, for example, about 20 ° C. to less than about 40 ° C. to facilitate recovery of the reaction product. Conversion to HFO-1234ze and selectivity are preferably at least about 70%, about 100%, preferably at least about 90%, about 100%, respectively, with a yield of about 35% to about 95%. preferable.

II. Formation of Compounds of Formula I A wide variety of raw materials are known and believed to be available for preparing compounds of formula (I) according to the present invention. For example, in certain embodiments, it may be preferable to prepare pentachloropropane (HCC-240) and expose the compound to one or more reactions to produce one or more compounds according to Formula (I). . Various other methods for preparing compounds according to formula (I) are described in US Pat. Nos. 5,710,352, 5,969,198, and 6,023,004, Are each incorporated herein by reference. Another method described in US Pat. No. 5,728,904 is said to be economical and suitable for large-scale use, and this method uses readily available raw materials. The process of this patent uses the following three steps: 1) formation of CCl ₃ CH ₂ CCl ₃ by reaction of vinylidene chloride and CCl ₄ ; 2) fluorine selected from TiCl ₄ , SnCl ₄ or mixtures thereof Conversion of CCl ₃ CH ₂ CCl ₃ to CF ₃ CH ₂ CF ₂ Cl by reaction with HF in the presence of an oxidization catalyst; and 3) CF ₃ CH ₂ CF ₂ Cl to CF ₃ CH ₂ CF ₂ H Reduction. Further, commercial quantities of HFC-245fa are available from Honeywell International Inc. Morristown, N .; J. et al. Is available from This HFC-245fa is used as a starting material for the present process for direct conversion to a fluoroolefin (eg, CF ₃ CH═CFH) by dehydrofluorination according to the process disclosed herein.

EXAMPLES Further features of the present invention are shown in the following examples, which should not be construed as limiting the claims in any way.

Reference Examples 1-21
In these reference examples, a vapor phase dehydrohalogenation reaction from CF ₃ CH ₂ CHF ₂ (HFC-245fa) to CF ₃ CH═CHF (HFC-1234ze) will be described. As shown in Table 1 below, a 50 inch catalyst was charged to a 22 inch (1/2 inch diameter) Monel tubular reactor. The reactor is installed in a heater having three zones (upper, middle and lower). The reactor inlet is connected to a preheater maintained at about 250 ° C. by electrical heating. Organic matter (HFC-245fa) is fed from a cylinder maintained at 65 ° C. The flow rate of inert N ₂ gas (20 sccm) is maintained throughout. The reactor temperature is set to the temperature shown in the table. HFC-245fa is fed through a gas flow regulator to a preheater maintained at a temperature of about 250 ° C. The gas stream exiting the preheater is passed through the catalyst bed at the desired temperature for a predetermined time at a pressure of about 2.5 to 5.3 psig. Samples taken at regular time intervals at the reactor outlet line are analyzed using on-line GC and GCMS. Finally, the effluent gas from the reactor is passed through a 20-60% KOH cleaning solution, and then the effluent gas from the cleaning solution is condensed to recover the product. The desired product CF ₃ CH═CFH (HFC-1234ze) is then separated from the mixture by distillation. Depending on the reaction conditions, the conversion of HFC-245fa is about 50% to about 100%, and the selectivity to HFC-1234ze is about 60% to about 100%. The trace amounts of by-products obtained were CHF ₃ and CH ₂ = CHF.

  The results are shown in Table 1 below.

Examples 22-24
In these examples, a gas phase dehydrohalogenation reaction from CF ₃ CH ₂ CHFC1 (HCFC-244fa) to CF ₃ CH═CHF (HFO-1234ze) is described. The procedures of Reference Examples 1 to 21 were repeated except that HCFC-244fa was used instead of HFC-245fa. The minor by-products identified by GC / MS (less than 0.5% as a mixture) were CF ₃ Cl and CF ₃ CH ₂ Cl.

  The results are shown in Table 2 below.

Reference Example 25
In this reference example, a liquid phase dehydrochlorination reaction from CF ₃ CH ₂ CHFC1 (HCFC-244fa) to CF ₃ CH═CHF (HFO-1234ze) will be described. Approximately 150 g of 20% KOH solution, 1 g of 18-crown ether, and 10 g of CF ₃ CHClCH ₂ F are charged into a 300 ml autoclave with a Teflon lining. The mixture is stirred at 50 ° C. for 6 hours. The progress of the reaction is monitored by taking samples every 30 minutes and analyzing them by GC and MS. After the specified reaction time, the gas mixture from the top of the column was transferred to a -70 ° C. recovery cylinder. Analysis and overall mass balance confirmed that the yield was 55%.

Thus, while several specific aspects of the invention have been described, various changes, modifications and improvements will readily occur to those skilled in the art. As revealed by this disclosure, such changes, modifications, and improvements are not expressly set forth herein, but are intended to be part of this description and the present invention. Is intended to be within the spirit and scope of Accordingly, the foregoing description is by way of example only and is not intended as limiting. The present invention is limited only as defined in the following claims and equivalents thereto.
The present invention relates to:
1. At least one of the following first formula:
_{CF 3 CH 2 CH m X 3} -m
A compound of at least one of the following second formulas:
CF ₃ CZ = CHF
A process for producing a fluorinated organic compound comprising a step of converting to a compound of the formula: wherein X is independently Cl, I or Br; Z is independently H or F; m is 1, 2 or 3]
2. The method of claim 1, wherein the conversion step is performed under conditions that effectively convert at least about 40% of at least one compound according to the first formula;
3. The method of claim 1, wherein the conversion step is performed under conditions that effectively convert at least about 80% of the at least one compound according to the first formula;
4). The method of claim 1, wherein the conversion step is performed under conditions that effectively convert at least about 90% of at least one compound according to the first formula;
5. The method of claim 1, wherein the conversion step is performed under conditions that effectively obtain at least one compound according to the second formula at a selectivity of at least about 95%.
6). The method of claim 1, wherein the conversion step is performed under conditions that effectively obtain at least one compound according to the second formula at a selectivity of at least about 90%;
7). At least one formula (I):
CF ₃ [C (R ¹ _a R ² _b )] _n C (R ³ _c R ⁴ _d ) (I)
A compound of at least one formula (II):
CF ₃ [C (R ¹ _a R ² _b )] _n−1 CZ═CHZ (II)
A process for producing a fluorinated organic compound comprising converting to a compound of the formula: wherein R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom or a group consisting of fluorine, chlorine, bromine and iodine Selected halogen, provided that at least one of R ¹ , R ² , R ³ and R ⁴ is halogen; a and b are independently equal to 0, 1 or 2 where (a + b) = 2 B and c are independently equal to 0, 1, 2 or 3 and (c + d) = 3; n is 1, 2, 3 or 4; and Z is independently H or halogen. Where Z at the terminal carbon is a halogen]
8). The method of claim 7, wherein the conversion step is performed under conditions that effectively convert at least about 40% of at least one compound according to formula (I),
9. The method of claim 7, wherein the conversion step is performed under conditions that effectively convert at least about 90% of the at least one compound according to formula (I),
10. The method of claim 7, wherein the conversion step is performed under conditions that effectively obtain at least one compound according to formula (II) with a selectivity of at least about 90%;
11. The method according to 7 above, wherein Z at the terminal carbon is fluorine,
12 14. The method according to 13 above, wherein n is 1.
13. 15. The method of 14, wherein the compound of formula (II) comprises HFO-1234ze,
14 The compound of the formula (I) is pentachloropropane (HCC-240), tetrachlorofluoropropane (HCFC-241), trichlorodifluoropropane (HCFC-242), dichlorotrifluoropropane (HCFC-243), chlorotrifluoropropane. (HCFC-244), pentafluoropropane (HFC-245), and all isomers thereof and combinations thereof, the method according to 7 above,
15. The method of claim 7, wherein the compound of formula (I) comprises HCFC-244fa,
16. The method of claim 7, wherein the compound of formula (I) comprises HCFC-245fa,
17. 8. The method of claim 7, wherein the converting step comprises catalytically converting the compound of formula (I) to one or more compounds of formula (II).
18. 18. The method according to 17 above, wherein the step of catalytically converting the compound of formula (I) comprises exposing the compound of formula (I) to a charge neutral metal catalyst.
19. The step of converting said compound of formula (I) by catalysis, comprising the step of exposing the compound of formula (I) to Ni ⁰ catalyst, the method described in the 17.

Claims (1)

The following first formula:
CF ₃ CH ₂ CHFCl
A compound of the following second formula:
CF ₃ CH = CHF
A process for producing a fluorinated organic compound comprising the step of converting to
The step of converting comprises gas phase contact of at least one charge neutral metal catalyst with the compound of the first formula;
The charge neutral metal catalyst is selected from the group consisting of Ni ⁰ catalyst, Pd ⁰ catalyst, Fe ⁰ catalyst, and combinations of two or more thereof;
Method.