GB1585938A

GB1585938A - Process for the production of 1,1,1-trifluoro-2-chlorethane

Info

Publication number: GB1585938A
Application number: GB16720/78A
Authority: GB
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1977-04-28
Filing date: 1978-04-27
Publication date: 1981-03-11
Also published as: ES469216A1; IT7849068A0; FR2388785A1; JPS53135909A

Description

(54) A PROCESS FOR THE PRODUCTION OF 1,1,1 TRIFLUORO-2-CHLORETHANE (71) We BAYER AKTIENGESELLSCHAFT, a body corporate organised under the Laws of Germany of 509 Leverkusen, Germany do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a process for the production of l,l,l-trifluoro-2chloroethane.

More particularly, the invention relates to a process for the production of 1,1,1 -trifluoro-2-chloroethane, optionally in admixture with 1,1,1-difluoro-1,2- dichloroethane, by reacting trichloroethylene with anhydrous hydrogen fluoride in the liquid phase optionally under pressure in the presence of small quantities of a fluorination catalyst in accordance with the following general empirical reaction formulae:

cat.

CHCl = CCI2 + 3 HF ç CF3-CH2Cl+2HCl cat.

CHCl = CCI2 + 2 HF < CF2Cl-CH2Cl+HCl By virtue of its properties (for example non-inflammability, low boiling point), I, I, I -trifluoro-2-chloroethane is an extremely versatile product. Thus, it has already been used as a constituent of aerosol packs (cf. for example US Patents Nos. 3,583,921 and 3,655,865; German Auslegeschrift No. 1,542,076), as an additive to gaseous pain killers (cf for example US Patent No. 3,325,352) even as a constituent of shampoos (cf for example French Patent No. 2,152,371).

In addition, I, I, I -trifluoro-2-chloroethane (R 133 a) is of particular interest as a possible replacement for perhalogenated fluorochloro alkanes because, unlike perhalogenated fluorochloro alkanes, it is degradable in the atmosphere (cf: for example "Spraydose verboten" Symposium, 17-18.2.77, Gottlieb Duttweiler institut, Ruschlikon Zurich 1977, page 209), and according to all previous investigations is toxicologically acceptable.

Although various processes have already been proposed for the production of I, I, l -trifluoro-2-chloroethane, they are still attended by considerable disadvantages. For example, it is formed alongside a number of other products in the chlorination of 1,1,1-trifluoroethane, in the reaction of antimony fluorides with CF2CICH2CI at 140 to 1500C/45 bars, in the reaction of 1,1,1,2-tetrachloroethane with HF and HgO at 85 to 950C (in addition to CF2Cl-CH2Cl), in the reaction of HF with CF2=CHCI in the presence of BF3 at 250C and, finally, in the reaction of trichlorethylene with HF in the presence of antimony catalysts at 170 to 1900C (cf Beilsteins Handbuch der Organ.Chemie, System No. 8, pages 139-140 E III 1).

Unfortunately, none of these processes is suitable for working on a commercial scale because either the processes are too complicated or the starting substances are not available in sufficient quantities.

It has also been proposed to react sym. tetrachloroethane with HF. According to W. B. Walley, J.Soc.Chem. ind. 66, 430 (1947), however, the liquid phase fluorination with HF in the presence of large quantities of SbCl5 at 120 to 1259C only leads to the corresponding monofluorinated and difluorinated compounds.

More highly fluorinated compounds are not observed.

The fluorination of trichloroethylene, a widely used commercial product, has always been of considerable interest. Two methods have been described for this purpose, namely fluorination in the gas phase and fluorination in the liquid phase.

Where fluorination is carried out in the gas phase, trichlorethylene and HF are passed together over catalysts, for example of chromium or aluminium or compounds of these metals. Although good yields can be obtained from gas phase fluorination reactions of this type, there are in general no suitable installations in which to carry them out. In addition, these processes are attended by the disadvantage that, because of the high temperatures involved, decomposition can occur both in the starting materials and also in the end products. At the same time, the catalysts are also deactivated by deposits.

Gas phase fluorination processes are described for example in DT-OS No.

1,442,835 and in DT-OS No. 2,032,098.

Where fluorination is carried out in the liquid phase (cf. for example DT-AS No. 1,020,968; DT-AS No. 1,104,496 or DT-AS No. 1,246,703), it has hitherto only been possible to obtain satisfactory yields with very large quantities of catalyst (for example antimony halides). In addition, it is necessary according to DT-AS No. 1,020,968 to use what is basically an unusual autoclave material, namely aluminum in order to obtain good yields. In spite of this considerable outlay, however, long reaction times are still necessary. For these reasons, the processes in question appear never to have been adopted for working on a commercial scale.

Although, by virtue of its properties, 1,1,1-trifluoro-2-chloroethane (R 133 a) would be eminently suitable for example for replacing the perhalogenated fluorochloro alkanes, such as CCI3F, CCI2F2, CClF2-CClF2 as a propel ant for aerosols, its poor availability is an obstacle to this commercial application.

Accordingly, there is a considerable need to find an economic and commercially workable process for the production of 1,1,1-trifluoro-2-chloroethane.

The present invention provides a process for the production of 1,1,1 -trifluoro- 2-chloroethane, optionally in admixture with 1,1 -difluoro-l 2-dichloroethane, which comprises reacting trichloroethylene with substantially anhydrous hydrogen fluoride in the liquid phase in the presence of a fluorination catalyst, comprising a combination of one or more antimony and/or arsenic compounds and one or more transition metal compounds. Preferably the trichloroethylene used is free from stabilizers.

We have surprisingly found that both the product yield and also the volumetime yield of conventional processes can be significantly improved by the process according to the invention. The reaction is so surprising because, hitherto, there have only been a few compounds, particularly antimony halides, which catalyze the Cl-F-exchange in the liquid phase chlorination of aliphatic chlorinated hydrocarbons (cf. A. K. Barbour et al., in "Advances in Fluorine Chemistry", Vol.

3, 1963, Butterworths London, page 181 and M. Hudlicky, "Chemistry of Organic Fluorine Compounds", Ellis Harwood, 1976, page 95).

It is not known what is responsible for the intensification of the fluorinating effect of conventional catalysts for liquid-phase fluorination reactions.

It has now surprisingly been found that it is possible to fluorinate trichlorethylene with HF in the presence of optionally stabilizer-free trichlorethylene in high yields and in short reaction times, even in the presence of only very small quantities i.e. catalytic quantities of the fluorination catalysts. The particular advantage of this procedure is that it is not necessary to use large quantities of catalyst so that there is no danger of any undesirable secondary reactions such as otherwise occur with halogen derivatives of the C2 series (cf. for example Houben-Weyl, Methoden der organ. Chemie, 1964, Vol. 5/3, pages 107 and 135).

In addition to the catalysts known per se based on antimony or arsenic compounds, transition metal compounds from Secondary Groups lb to 7b or from the Eighth Main Group (cf. Periodic Table of the Elements, E. H. Sargent & Co., 1964, or Sanderson, Chemical Periodicity, Reinhold Publishing Corp, New York 1962) are in -combination with the antimony and/or arsenic compounds as the fluorination catalysts in the process according to the invention.

Transition metals may primarily be regarded as the elements belonging to the Secondary Groups of the Periodic System, namely copper to nickel, silver to palladium and gold to platinum. The following elements are mentioned as preferred examples: nickel, cobalt, rare earth metals, iron, copper, palladium, platinum, manganese, vanadium, molybdenum, zirconium, chromium, zinc, mercury, cadmium, silver. Chromium, nickel, cobalt and iron, and especially zinc, cadmium and mercury, are particularly suitable.

These elements are preferably used in the form of their chlorides or fluoride, although they may also be used in the form of the metals or in the form of other compounds, for example sulphates or complex compounds. Mixtures of the metal compounds are of course also suitable.

Fluorination catalyst known per se, such as are described in Houben-Weyl, loc. cit., pages 124 et seq, may be used as one catalyst component of the catalyst combination used.

SbCl5 mixtures of SbCI3 and chlorine, mixtures of SbCl3 and SbCl5 or reaction Droducts or the above-mentioned compounds with HF which correspond to the general formula SbXnYs-n (X = Cl, Y = F), are particularly suitable for the process according to the invention. It is preferred to use SbCl5. According to a particular embodiment of the present invention, the catalyst is a combination of SbCl5 and a zinc, cadmium and/or mercury compound. The catalyst is used in a quantity of from about 0.005 to 0.2 mole per mole of trichlorethylene and preferably in a quantity of about 0.008 to 0.1 mole. The Sb-compounds may be replaced by the corresponding arsenic compounds.

The additional catalysts are used in similar quantities (molar quantities) to the antimony and/or arsenic components of the fluorination catalyst according to the invention. In general, quantities of as small as about 0.001 mole (based on trichloroethylene) are sufficient. It is not necessary to use more than about 0.4 mole. In general, it is preferred to use quantities of about 0.008 to 0.1 mole.

The Sb or As component is best present in excess in the catalyst mixture, although the other component may also be present in excess. It is possible for example to use from about 10 to 400 mole % of the transition metal catalyst, based on the quantity of the Sb or As compound.

Compounds possibly existing within these composition ranges (such as for example the complex compunds Ni(SbFs)2 aq known in the aquo system or the corresponding Cu or Mn compounds) are equally suitable.

The small quantities of fluorination catalyst used in accordance with the invention are sufficient, above all when the trichlorethylene used does not contain any of the usual stabilizers. It is known that stabilizers such as, for example, amines, epoxides or other organic substances can be added to trichloroethylene (cf. for example Ullmann, Enzyklopadie der Techn. Chemie, 1975, Vol. 9, page 458). These stabilizers can obviously inhibit the catalysts and, for this reason, should be removed. If stabilized trichlorethylene is used with antimony halides, the reaction mixture turns black in color and after a while tar-like products are deposited.

Although it is not completely clear whether these tar-like products adversely affect the process according to the invention, deposits of the type in question must impair the process to a considerable extent, particularly where it is carried out continuously. According to the invention, therefore, it is preferred to use nonstabilized trichlorethylene. The non-stabilized trichlorethylene is obtained for example in known manner (cf. Ullmann, I.c. Vol. 9, page 455) by the dehydrohalogenation of sym. tetrachloroethane and is directly reacted in accordance with the invention. It is also possible to use trichlorethylene containing inactivated stabilizer. This may be done for example by contacting the trichlorethylene with HF or other suitable substances before the actual reaction and in the absence of the catalyst.

The hydrogen fluoride is used in standard commercial, substantially anhydrous form. Its water content does not exceed about 01% by weight.

In one general embodiment, the process according to the invention is carried out by thoroughly mixing the reaction components, catalysts, HF and trichlorethylene in a pressure vessel. Thereafter the pressure vessel is brought to an initial pressure of from about 5 to 20 bars, preferably from about 10 to 15 bars, optionally by the introduction of an inert gas such as N2 or HCI.

With further heating to around 10e-145"C, preferably 1 1O--1350C, the pressure continues to rise (to around 3040 bars, depending on the setting of the pressure stabilizing valve) and is then kept constant. After about 0.5 to 3 hours, the pressure vessel is cooled and the gaseous products escaping are condensed after the usual purifying and drying operations. It is of course also possible to apply higher pressures, although this should be avoided for economic reasons.

It is particularly important that the readily volatile hydrogen fluoride remains in intimate contact with the substance to be fluorinated, even during the heating phase.

The reaction may be carried out both in batches and also continuously, providing the reaction apparatus is set up accordingly.

The process according to the invention, in which it is preferred to use a fairly large excess of HF (2 to 10 times and preferably 4 to 8 times the molar amount of the trichlorethylene), may be carried out in conventional pressure vessels of, for example, steel, nickel, monel. The nature and constituent material of the apparatus used do not have to meet any particular requirements. The process according to the invention is carried out in apparatus known per se, of the type described for example in Houben-Weyl, loc. cit., page 97.

In addition to 1,1,1 -trifluoro-2-chloroethane, 1,1 -difluoro- 1 ,2-dichloroethane may also be formed during the fluorination reaction, particularly in cases where fairly small quantities of hydrogen fluoride are used. This product is also extremely valuable because it can also be reacted by further fluorination to form 1,1,1trifluoro-2-chloroethane. However, l,l-difluoro-l,2-dichloroethane may also be used in its own right, for example as a solvent, cleaning agent or as an intermediate product for numerous other reactions (for example to form CF2 = CHCI). If it is desired to obtain a larger proportion of I, I -difluoro- 1,2-dichloroethane, it is merely necessary to use a smaller excess of HF.

The products obtained in accordance with the invention are extremely simple to work up. Following the removal of HCI and excess HF, the reaction product is distilled. since the boiling points of the two compounds are far apart from one another and since no tetrafluorinated- compound is formed, l,l,l-trifluoro-2- chloroethane immediately accumulates in highly pure form (purity 99.9% and more), which is of considerable importance in one field of application, namely aerosols, while l,1-difluoro-2-chloroethane initially remains in the distillation sump and may then be separately distilled.

The process according to the invention is illustrated in the following Examples: Example 1.

6.25 g (0.0234 mole of anhydrous mercury-ll-chloride, 13.98 g (0.0467 mole) of antimony pentachloride and 400 g (20 moles) of anhydrous hydrogen fluoride were thoroughly mixed in a 2-liter autoclave equipped with a pressure condenser and stirrer. Following the addition -of 328.5 g (2.5 moles) of trichlorethylene, which had been extracted by shaking with hydrogen fluoride to remove the stabilizers present, the apparatus was placed under a pressure of about 15 bars with dry nitrogen. On heating to around 1300C, the pressure increased rapidly, being maintained at 36 bars by means of a pressure stabilizing valve. After about 1.5 hours, the autoclave was cooled to 3040 C and vented. After passing through a water-filled washing vessel followed by a calcium chloride drying tube, the volatile products escaping were condensed in traps cooled to around -50"C, giving 282 g of condensate wich, after distillation, produced 272 g (92% of the theoretical) of 1,1,1- trifluoro-2-chloroethane (b.p. 6.90C) and 10 g of 1,l-difluoro-1,2-dichloroethane (b.p. 47"C).

l,1-Difluoro-l,2-dichloroethane may be re-reacted to form l,l,l-trifluoro- 2-chloroethane.

Products of relatively low fluorine content remaining behind in the autoclave and products dissolved in the washing liquid were not taken into consideration.

Example 2.

In the evacuated and nitrogen-fil'ed apparatus of Example 1, 400 g (20 moles) of hydrogen fluoride and 328.5 g (2.5 moles) of trichlorethylene were again reacted, re-using the catalyst of Example I for 1.25 hours at 135"C/36--40 bars to form 263 g (89 of the theoretical) of I, I, I -trifluoro-2-chloroethane and 11 g of l,l-difluoro-2- chloroethane.

Example 3.

In the apparatus of Example 1, 1.6 g (0.0155 mole) of anhydrous zinc fluoride, 9.32 g (0.031 mole) of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles) of trichlorethylene over a period of 1.5 hours at 1250C/30 bars to form 225 g (76% of the theoretical) of 1,1,1 -trifluoro-2-chloroethane and 32 g of l,l-difluoro-1,2- dichloroethane.

Example 4.

In the apparatus of Example 1, 3.14 g (0.0234 mole) of anhydrous copper-ll- chloride, 13.98 g (0.0467 mole) of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles) of trichlorethylene over a period of 1.75 hours at 1320C/36 bars to form 231 g (81.5% of the theoretical) of l,l,1-trifluoro-2-chloroethane and 18 g of l,l-difluoro-1,2- dichloroethane.

Example 5.

In the apparatus of Example 1, 1.03 g (0.0234 mole) of anydrous nickel chloride, 13.98 g (0.0467 mole) of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles) ot trichlorethylene over a period of 1.5 hours at 1320C/34 bars to form 248 g (83% of the theoretical) of 1,1,1 -trifluoro-2-chloroethane and 24 g of 1,1 -difluoro- 1,2- dichloroethane.

Example 6.

In the apparatus of Example 1, 4 g (0.031 mole of anhydrous cobalt chloride, 18.64 g (0.062 mole) of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles) of trichlorethylene over a period of 1.25 hours at 1300C/32 bars to form 251 g (85% of the theoretical) of l,1,l-trifluoro-2-chloroethane and 12 g of 1,1-difluoro-1,2- dichloroethane.

Example 7.

In the apparatus of Example 1, 2.53 g (0.0156 mole) of anhydrous iron(III)chloride, 13.98 g (0.0467 mole) of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles) of trichlorethylene over a period of 1.5 hours at 1 320C/36 bars to form 216 g (73% of the theoretical) of 1,1,1-trifluoro-2-chloroethane and 35 g ot I,l-dlfluoro 1 ,2-dichloroethane.

Example 8.

In the apparatus of Example 1, 2.55 g (0.0234 mole) of anhydrous chromium(lll)fluoride, 13.98 g (0.0467 mole) of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles) of trichlorethylene over a period of 2 hours at 1300C/34 bars to form 247 g (84% of the theoretical) of 1,1,1-trifluoro-2-chloroethane and 26 g of l,l-difluoro- 1,2-dichloroethane.

Example 9.

In the apparatus of Example 1, 1.3 g (0.0073 mole) of anhydrous palladium chloride, 13.27 g (0.0441 mole) of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles of trichloroethylene over a period of 1.75 hours at 1280C/30 bars to form 177 g (60% of the theoretical) of 1,1,1-trifluoro-2-chloroethane and 83 g of I,l-difluoro-1,2-dichloroethane.

Example 10.

In the apparatus of Example 1, 8 g (0.0235 mole) of anhydrous platinum(lV)chloride, 13.98 g (0.047 mole of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 a (2.5 moles of trichlorethylene over a period of 1.25 hours at 128"C/30 bars to form 173 g (58% of the theoretical) of 1,1,1 -trifluoro-2-chloroethane and 70 g of I,l-difluoro- 1 ,2-dichloroethane.

Example 11.

In the apparatus of Example 1, 4 g (0.01 mole) of anhydrous tungsten(Vl)chloride, 9.09 g (0.03 mole) of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles) of trichlorethylene over a period of 1.25 hours at 1 280C/30 bars to form 167 g (56.5% oT the theoretical) of 1,1,1-trifluoro-2-chloroethane and 109 g of 1,1 difluoro- 1 ,2-dichloroethane.

Example 12.

In the apparatus of Example 1, 5.1 g (0.021 mole) of anhydrous lanthanum chloride, 18.64 g (0.062 mole) of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles) of trichlorethylene over a period of 1.25 hours at 1280C/30 bars to form 234 g (79% of the theoretical) of 1,1,1 -trifluoro-2-chloroethane and 26 g of 1,1 -difluoro- 1,2- dichloroethane.

Example 13.

In the apparatus of Example 1, 2.6 g (0.0155 mole) of anhydrous zirconium fluoride, 18.64 g (0.062 mole of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles) of trichlorethylene over a period of 1.25 hours at 1280C/30 bars to form 237 g (80% of the theoretical) of 1,1,1 -trifluoro-2-chloroethane and 26 g of 1,1 -difluoro- 1,2- dichloroethane.

Example 14.

In the evacuated and nitrogen-filled apparatus of Example 13, 220 g (11 moles) of hydrogen fluoride and 657 g (5 moles of trichlorethylene were similarly reacted, re-using the catalyst of Example 13, over a period of 1.5 hours at 1300C/30 bars to form 581 g (88% of the theoretical) of 1,l-difluoro-1,2-dichloroethane and 5 g of 1,1,1 -trifluoro-2-chloroethane.

Example 15.

In the apparatus of Example 1, 5.7 g (0.0312 mole) of anhydrous cadmium chloride, 18.64 g (0.062 mole) of antimony pentachloride and 200 g (10 moles) of hydrogen fluoride were stirred together and reacted with 336 g (2.5 moles) of 1,1 difluoro-l,2-dichloroethane over a period of 2 hours at 1320C/38 bars to form 278 g (94% of - the theoretical) of 1,1,1 -trifluoro-2-chloroethane.

Example 16.

In the apparatus of Example 1, 2.14 g (0.023 mole) of manganese (lI)fluoride, 13.98 g (0.047 mole) of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles) of trichlorethylene to form 171 g (58% of the theoretical) of l,l,l-trifluoro-2- chloroethane and 93 g of l,1-difluoro-I,2-dichloroethane.

Example 17.

In the apparatus of Example 1, 1.31 g (0.0156 mole of anhydrous aluminum fluoride, 13.98 g (0.047 mole) of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles) of trichlorethylene over a period of 1.75 hours at 1280C/30 bars to form 233 g (79% of the theoretical) of l,l,1-trifluoro-2-chloroethane and 34 g of l,l-difluoro-1,2- dichloroethane.

Example 18.

In the apparatus of Example 1, 2.32 g (0.0244 mole) of anhydrous magnesium chloride, 13.98 g (0.047 mole) of antimony pentachloride and 400 g (20 moles) of hydrogen fluoride were stirred together and reacted with 328.5 g (2.5 moles) of trichlorethylene over a period of 1 hour at 1340C/38 bars to form 151 g (51% of the theoretical) of 1,1,1 -trifluoro-2-chloroethane and 83 g of 1,1 -difluoro- 1,2- dichloroethane.

Example 19.

In the apparatus of Example 1, 3.5 g (0.0235 mole) of anhydrous manganese(ll)sulphate, 13.98 g (0.047 mole) of antimony pentachloride and 400g (20 moles) of hydrogen chloride were stirred together and reacted with 328.5 g (2.5 moles) of trichlorethylene over a period of 1.5 hours at 1 200C/30 bars to form 181 g (61% of the theoretical) of 1,1,1-trifluoro-2-chloroethane and 86 g of l,l-difluoro- 1 2-dichloroethane.

Example 20.

In the apparatus of Example 1, 15 g of nickel powder which had been treated with moist hydrogen fluoride were stirred with 28 g (0.0935 mole) of antimony pentachloride and 640 g (32 moles) of hydrogen fluoride and reacted with 526 g (4 moles) of trichlorethylene over a period of 2 hours at 1200C/20 bars to form 386 g (81% of the theoretical) of 1,1,1-trifluoro-2-chloroethane and 61 -g of l,l-difluoro- 1 ,2-dichloroethane.

WHAT WE CLAIM IS: 1. A process for the production of l,1,1-trifluoro-2-chloroethane, optionally adniixture with l,1-difluoro-1,2-dichloroethane, which comprises reacting trichloroethylene with substantially anhydrous hydrogen fluoride in the liquid phase in the presence of a fluorination catalyst comprising a combination of one or more antimony and/or arsenic compounds and one or more transition metal compounds.

2. A process as claimed in claim 1, wherein the trichloroethylene is free from stabilisers.

3. A process for the production of 1,1,1-trifluoro-2-chloroethane, optionally in admixture with 1,1 -difluoro- I ,2-dichloroethane, which comprises reacting trichloroethylene which is substantially free from stabilisers with substantially anhydrous hydrogen fluoride in the liquid phase in the presence of a fluorination catalyst, comprising a combination of one or more antimony or arsenic compounds and one or more transition metal compounds.

4. A process for the production of l,1,1-trifluoro-2-chloroethane, optionally in admixture with 1,1 -difluoro- 1 2-dichloroethane, which comprises reacting trichloroethylene which is substantially free from stabilisers with substantially anhydrous hydrogen fluoride in the liquid phase and in the presence of a catalytic quantity of a fluorination catalyst comprising a combination of arsenic or antimony compounds and one or more transition metal compounds.

5. A process as claimed in claim 4, characterised in that the trichloroethylene is produced from sym.tetrachloroethane and directly reacted.

6. A process as claimed in claim 4, characterised in that the trichloroethylene is brought into contact with HF before addition of the catalyst.

7. A process as claimed in any of claims 1 to 6, wherein the transition metal compound comprises one or more of zinc, cadmium, mercury, nickel, cobalt and iron.

8. A process as claimed in any of claims 1 to 7, wherein the catalyst is a combination of SbCI5 and a zinc, cadmium and/or mercury compound.

9. A process as claimed in any of claims I to 8, wherein the antimony a

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

Example 20.

In the apparatus of Example 1, 15 g of nickel powder which had been treated with moist hydrogen fluoride were stirred with 28 g (0.0935 mole) of antimony pentachloride and 640 g (32 moles) of hydrogen fluoride and reacted with 526 g (4 moles) of trichlorethylene over a period of 2 hours at 1200C/20 bars to form 386 g (81% of the theoretical) of 1,1,1-trifluoro-2-chloroethane and 61 -g of l,l-difluoro- 1 ,2-dichloroethane.

WHAT WE CLAIM IS: 1. A process for the production of l,1,1-trifluoro-2-chloroethane, optionally adniixture with l,1-difluoro-1,2-dichloroethane, which comprises reacting trichloroethylene with substantially anhydrous hydrogen fluoride in the liquid phase in the presence of a fluorination catalyst comprising a combination of one or more antimony and/or arsenic compounds and one or more transition metal compounds.
2. A process as claimed in claim 1, wherein the trichloroethylene is free from stabilisers.
3. A process for the production of 1,1,1-trifluoro-2-chloroethane, optionally in admixture with 1,1 -difluoro- I ,2-dichloroethane, which comprises reacting trichloroethylene which is substantially free from stabilisers with substantially anhydrous hydrogen fluoride in the liquid phase in the presence of a fluorination catalyst, comprising a combination of one or more antimony or arsenic compounds and one or more transition metal compounds.
4. A process for the production of l,1,1-trifluoro-2-chloroethane, optionally in admixture with 1,1 -difluoro- 1 2-dichloroethane, which comprises reacting trichloroethylene which is substantially free from stabilisers with substantially anhydrous hydrogen fluoride in the liquid phase and in the presence of a catalytic quantity of a fluorination catalyst comprising a combination of arsenic or antimony compounds and one or more transition metal compounds.
5. A process as claimed in claim 4, characterised in that the trichloroethylene is produced from sym.tetrachloroethane and directly reacted.
6. A process as claimed in claim 4, characterised in that the trichloroethylene is brought into contact with HF before addition of the catalyst.
7. A process as claimed in any of claims 1 to 6, wherein the transition metal compound comprises one or more of zinc, cadmium, mercury, nickel, cobalt and iron.
8. A process as claimed in any of claims 1 to 7, wherein the catalyst is a combination of SbCI5 and a zinc, cadmium and/or mercury compound.
9. A process as claimed in any of claims I to 8, wherein the antimony and/or arsenic compound is used in a quantity of from 0.008 to 0.1 mole per mole of trichloroethylene.
10. A process as claimed in any of claims 1 to 9, wherein the transition metal compound is used in a quantity of from 0.008 to 0.1 mole per mole of trichloroethylene.
11. A process as claimed in any of claims 1 to 10, wherein the catalyst comprises from 10 to 400 mole % of the transition metal compound based on the antimony or arsenic compound.
12. A process as claimed in any of claims 1 to 11, wherein the reaction is carried out under pressure.
13. A process for the production of 1,1,1-trifluoro-2-chloroethane optionally in admixture with 1,1 -difluoro- I ,2-dichloroethane substantially as herein described with reference to any of the specific Examples.
14. 1,1,1 -trifluoro-2-chloroethane optionally in admixture with 1,1 -difluoro- 1,2-dichloroethane when produced by a process as claimed in any of claims 1 to 13.