WO1991005753A1

WO1991005753A1 - Process for chlorofluoropropanes

Info

Publication number: WO1991005753A1
Application number: PCT/US1990/005657
Authority: WO
Inventors: Carl George Krespan; Allen Capron Sievert; Frank Julian Weigert
Original assignee: E.I. Du Pont De Nemours And Company
Priority date: 1989-10-16
Filing date: 1990-10-11
Publication date: 1991-05-02
Also published as: HU906464D0; CN1051904A; HUT55336A; AU6735490A

Abstract

A process for the preparation of chlorofluoropropanes of the formula C3HCl2F5 by contacting monofluorodichloromethane with tetrafluoroethylene in the presence of a modified aluminum chloride catalyst at a temperature of 0 to 150 °C. The novel compound CF3CCl2CHF2 is also disclosed.

Description

TITLE PROCESS FOR CHLOROFLUOROPROPANES

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates to a process for the preparation of chlorofluorocarbons and to a novel composition 2,2-dichloro-l,1,1,3,3-pentafluoropropane. Background

For modern technological advances, particularly in the electric field, utmost cleanliness of the electronic components has become an important and necessary requirement. For example, in the manufacture of modern electronic circuit boards with increased circuitry and component densities, thorough and effective cleaning of the boards after soldering is of primary importance. Cleaning of electronic circuit boards is presently done for the most part by solvent washing utilizing various solvents and processes.

The solvent of choice at the present time is 1, l,2-trichloro-l,2,2-trifluoroethane (CFC-113) because this solvent provides the necessary characteristics required of an effective solvent such as convenient atmospheric boiling point, non-flammability, low toxicity, inertness to various materials of construction, high stability and high solvency. CFC-113 is often used with small amounts of co-solvent such as acetone or methanol to enhance certain solvency characteristics. CFC-113 and CFC-113-based solvents are also extensively used in cleaning of precision machine parts. In recent years, however, CFC-113 has been suspected of contributing to the depletion of the stratospheric ozone layer. Because of its unusually high stability, it is believed that CFC-113 remains intact in the earth's atmosphere until it reaches the stratosphere and there undergoes decomposition, the decomposition product bringing about the destruction of the ozone layer.

It is, therefore, obvious that there is an urgent need in the industry for a solvent to replace CFC-113 which will provide the beneficial solvent characteristics of CFC-113, but at the same time have little or no stratospheric ozone depletion potential.

It is an object of the present invention to provide an effective chlorofluorocarbon solvent system. It is a further object of the invention to provide an effective chlorofluorocarbon solvent system which has little or no effect upon the stratospheric ozone layer. It is still a further object of the present invention to provide an improved process for the manufacture of chlorofluoropropanes.

SUMMARY OF THE INVENTION This invention provides a process for the preparation of hydrogen-containing chlorofluoro- propanes represented by the formula C3HCI2F5, said process comprising contacting monofluorodichloro- ethane with tetrafluoroethylene in the presence of a modified aluminum chloride catalyst at a temperature of from about 0°C to about 150°C and recovering hydrogen-containing chlorofluoropropanes. Said modified aluminum chloride being prepared by contacting anhydrous aluminum chloride with chlorofluorocarbon of 1 to 2 carbon atoms and removing liquid products therefrom. This invention also provides a novel compound 2,2-dichloro- 1,1,1,3,3-pentafluoropropane. DETAILED DESCRIPTION OF THE INVENTION A solvent system which will be used as a replacement for CFC-113 should have characteristics very similar to those of CFC-113 such as relatively low atmospheric boiling point (CFC-113 boils at approximately 47°C) , non-flammability, low toxicity, inertness to various materials of construction, high solvency, a in-use stability. For the replacement solvent tc have little or no effect upon the ozone depletion process, the solvent must have stability characteristics somewhat different from that of CFC-113. The solvent should be sufficiently stable to be used effectively in various cleaning processes, but should be unstable enough to completely or almost completely decompose in the troposphere so that little or none will survive to reach the stratosphere. It is generally believed by those skilled in the art that such stability characteristics can be achieved for the most part by hydrogen-containing chlorofluorocarbons- (HCFC's). The rationale being that such hydrogen-containing chlorofluorocarbons now undergo dehydrohalogenation, such as dehydro- chlorination, in the atmosphere such that the compounds do not survive to reach the stratosphere.

It has now been found that certain hydrogen-containing chlorofluorocarbon derivatives of propane represented by the formula C3HCI2F5 have the necessary characteristics discussed above. Thus in terms of atmospheric boiling points, the presently known isomeric C3HCI2F5 are reported to have boiling points fairly close to that of CFC-113, i.e., in the range of from about 50°C to about 56°C. Thus, CHCIFCCIFCF3 (I) boils at 56°C, CHF₂CC1FCC1F₂ (II) boils at 56.3°C, CHC1₂CF₂CF₃ (III) boils at 53.0°C, CHC1FCF₂CC1F₂ (IV) boils at 52.0°C, and CC1F₂CHC1CF₃ (V) boils at 50.4°C. Boiling points reasonably close to that of CFC-113 are desirable so that presently used solvent cleaning systems and processes can be used without too much modification.

While the above-disclosed hydrochlorofluoro¬ propanes are known and should be useful in solvent cleaning system, there is no satisfactory process for preparing them, particularly in large quantities required for industrial uses.

At present, a great majority of chlorofluoro¬ carbons and hydrochlorofluorocarbons, particularly those produced in large quantities, are manufactured by processes involving halogen exchange reactions, i.e., replacing one or more chlorine atoms of a halocarbon by a fluorine atoms(s) either by the reaction with a fluorinating agent such as antimony chlorofluorides and the like, or by the reaction of the halocarbon with hydrogen fluoride in the presence of a fluorination catalyst such as antimony halide, chromium oxide, aluminum fluoride and the like. Such processes involve at least the steps of preparing the required chlorocarbons and then carrying out the fluorine exchange reaction on the chlorocarbons. The preparation of chlorocarbons or hydrogen-containing chlorocarbons generally proceed reasonably well with one or two carbon compounds; however, with three carbon atom compounds, i.e., the propane series, both the preparation of the suitable chloropropanes and the subsequent halogen exchange reactions proceed with great difficulty and usually in unsatisfactory low yields.

In accordance with the present invention, it has now been found that certain isomeric hydrogen-containing chlorofluoropropanes of the formula C3HCI2F5 can be prepared readily in good yields by the reaction of mσnofluorodichloromethane with tetrafluoroethylene in the presence of a modified aluminum chloride catalyst. The reaction may be represented by equation (1).

catalyst CHC1₂F + CF₂=CF₂ > C₃HC1₂F₅ (1)

"C3HCI2F5" in equation (1) represents an isomeric mixture of hydrogen-containing chlorofluoropropanes. The reaction of CHCI2F with

to produce hydrogen-containing chlorofluoro- propanes has been disclosed by Joyce in U.S. Patent 2,462,402 and by Coffman, et. al. in The Journal of the American Chemical Society, Vol. 71, pages 979-980 (1949) wherein the catalyst used was ordinary aluminum chloride. The disadvantage of the process as disclosed above using ordinary aluminum chloride as the catalyst, is the extensive halogen exchange reaction which takes place. At least one aspect of such exchange is the production of a fairly large amount of chloroform (CHCI3) from CHC1₂F which means considerable loss of valuable reactant. The other disadvantage arising from extensive halogen exchange is that in this particular reaction the chloroform produced forms azeotropes with most of the C3HCI2F.3 isomers which makes recovery of C HC1 F5 by conventional industrial means, e.g., distillation, difficult and expensive.

It has now been found that the above-described reaction (1) can be carried out providing higher yields of desired hydrogen-containing chlorofluoro- propanes and surprisingly with little or no conversion of the monofluorodichloromethane to chloroform when said reaction is carried out using a modified aluminum chloride catalyst, to be described below, in place of the art-taught ordinary aluminum chloride.

Above-cited Joyce and Coffman, et. al. references describe the hydrogen-containing chlorofluoropropane product as 1,3-dichloro- 1,2,2,3,3-pentafluoropropane, i.e., CHC1FCF₂CC1F2; however, Paleta, et. al. in Coll. Czech. Chem. Comm. Vol. 35, page 1867-1875 (1971) reported that the chlorofluoropropane products actually obtained were an isomeric mixture consisting of about 41% 1,3-dichloro-l,2,2,3,3-pentafluoropropane, CHC1FCF₂CC1F₂, and about 59% 1,l-dichloro-2,2,3,3,3- pentafluoropropane, CHC1₂CF₂CF3.

Applicants have now found that by using the modified aluminum chloride catalyst instead of ordinary aluminum chloride, not only are higher yields of hydrogen-containing chlorofluoropropanes obtained, and the formation of chloroform from monofluorodichloromethane either eliminated or greatly reduced, but a heretofore unknown isomeric hydrogen-containing chlorofluoropropane, i.e., 2,2-dichloro-l,1,3,3,3-pentafluoropropane,

CHF2CCI2CF3, is also obtained in appreciable quantities.

This new isomeric dichloropentafluoropropane, CHF2CCI2CF3, should be particularly desirable from structural considerations since the hydrogen atom is located on one of the terminal carbon atoms of the propane molecule and both chlorine atoms are located on the middle carbon atom. Such structure should insure greater ease of dehydrochlorination in the atmosphere so that none of the compound should survive to reach the stratosphere and participate in the ozone depletion process. This isomer may also be less toxic than the other isomers.

On the other hand it is important that cleaning compositions possess adequate stability under use conditions. Dehydrochlorination is known in the art to be typically more facile than dehydro- fluorination. Loss of hydrogen halides under use conditions is undesirable since it can result in corrosion of metal parts. The new CHF2CCI2CF isomer appears to have adequate stability under mild conditions as indicated by the reactivity of a mixture of three C₃HC1₂F₅ isomers - CHC1₂CF₂CF3,

CHC1FCF₂CC1F₂, and CHF₂CC1₂CF₃- with aqueous NaOH, see Example 10. The isomer distribution before and after the reaction with NaOH indicated that the CHCI2CF2CF3 isomer was the least stable of the three isomers under these conditions.

The claimed reaction process is carried out by contacting onofluorodichloromethane with tetra¬ fluoroethylene in the presence of a modified aluminum chloride catalyst in the temperature range of from about 0°C to about 150°C.

The modified aluminum chloride catalysts used in the process of the invention are prepared by treating anhydrous aluminum chloride with an excess of chlorofluorocarbons, hydrochlorofluorocarbons, or hydrofluorocarbons such as CH3F, CH₂F₂, CHF3,

CC1₂FCC1₃, CC1F₂CC1₃, CF3CCI3, CF₃CC1₂F, CF₃CC1F₂, CHC1₂CC1₂F, CHCIFCCI3, CHC1₂CC1F₂, CHC1FCC1₂F, CHF₂CC1₃, CHCI CF3, CHC1FCC1F₂, CHF₂CC1₂F, CHCIFCF3, CHF₂CC1F₂, C₂HF₅, CHC1FCHC1₂, CH₂C1CC1₂F, CH₂FCC1₃, CHC1FCHC1F, CHC1₂CHF₂, CH₂C1CC1F₂, CH₂FCC1₂F,

CHC1FCHF₂, CH₂C1CF₃, CH₂FCC1F₂, CHF₂CHF₂, CH₂FCF₃, CH₂C1CHC1F, CH₂FCHC1₂, CH₃CC1₂F, CH₂C1CHF₂, CH₂FCHC1F, CH₃CC1F₂, CH₂FCHF₂, CH3CF3, CH₂FCH₂C1, CH3CHCIF, CH₂FCH₂F, CH₃CHF₂, and C₂H₅F; preferably CC1₂F₂, CHC1₂F, CHC1F₂, CH₂C1F, CC1₂FCC1₂F, CC1₂FCC1F₂, CC1F₂CC1F₂; and most preferably CCI3F. Propane derivatives displaying the structural features shown above may also be used in the process of this invention. The reaction between aluminum chloride and the chlorofluorocarbons, hydrochlorofluorocarbons, or hydrofluorocarbons occurs, for the most part, spontaneously and is exothermic. In certain instances, such as with C2 chlorofluorocarbons, slight heating may be used advantageously. For compounds containing -CF3 groups such as CHF₃, CCI3CF3, CHC1₂CF₃, CH₂C1CF₃, and CH3CF3 more vigorous conditions are required to effect reaction with AICI3, and the reaction is best carried out under the pressure developed autogenously by the reactants. After the reaction has subsided, the liquid products are removed, generally under reduced pressures to provide a modified aluminum chloride catalyst which will usually contain from about 3 to about 68% fluorine. The liquid product from the reaction of chlorofluorocarbons with A1C1₃ includes products which are produced by halogen exchange reaction with the aluminum chloride as well as rearranged chlorofluorocarbons. Thus, when CCI3F is used to modify the aluminum chloride, the halogen exchange product will be CC1₄, and when CHC1₂F is used, the product is CHCI3. When CC1₂FCC1F2 is used to modify the aluminum chloride, the liquid products of the reaction include CCI3CF3, CCI3CCIF2, and C->Clg. The solid modified aluminum chloride product of the reaction of AICI3 with chlorofluorocarbons may be separated from the liquid products by filtration, by distillation or vacuum transfer of the liquid products from the modified aluminum chloride, or, alternatively, the modified aluminum chloride catalyst may be used as a suspension for subsequent reactions.

Since the instant process involves the addition of one mole of monofluorodichloromethane to one mole of tetrafluoroethylene as indicated by equation (1), the appropriate molar ratio of the reactants should be 1:1 although a slight excess of either reactant may be used if desired. A large excess of monofluorodichloromethane could result in chloroform formation despite the use of modified aluminum chloride catalyst and should be avoided. A large excess of tetrafluoroethylene, while not harmful, serves no useful purpose. Both reactants, CHC1₂F and CF₂=CF₂, are articles of commerce and are readily available. The tetra luoroethylene used in the process of the invention may be optionally inhibited with d-limonene to reduce the possibility of initiating a hazardous polymerization.

The present invention process can be carried out either batch-wise or in a continuous fashion. In the continuous process, a mixture of monofluoro¬ dichloromethane and tetrafluoroethylene is passed through or over a bed of modified aluminum chloride at suitable temperature and pressure and the desired products recovered from the effluent by conventional means such as fractional distillation.

In the batch process all of the reactants may be combined together in the reactor. Alternatively, the reactor may be initially charged with catalyst and tetrafluoroethylene, and the dichlorofluoro- methane metered into the reactor at the desired rate. If the reactor is charged with catalyst and CHC1₂F, it is important that the reaction be kept cold to minimize the disproportionation of CHC1₂F to chloroform which can occur even with the modified aluminum chloride catalyst under favorable circumstances.

The process of the invention may be run with or without a solvent. If a solvent is used it must be one which will not react with the modified aluminum chloride catalyst and have a boiling point appropriate for eventual separation of the C3HCI2F5 isomeric mixture. Solvents that can be used for the process of the invention include unreactive chlorocarbons, such as CH₂Cl2 or unreactive chlorofluorocarbons, such as CF3CCI2CF3. A preferred solvent is CHCI2CF3; the most preferred solvent is the product, the C₃HCl2F₅ isomeric mixture or any of the individual isomers.

The reaction temperature may be varied widely in the range of from about 0°C to about 150°C. The preferred temperature range is from about 10°C to about 100°C. The most preferred range is from about 25°C to 70°C.

Pressure likewise may be varied widely from sub-atmospheric to superatmospheric, but preferably the reaction is carried out at somewhat elevated pressures, particularly at pressures generated autogenously in conformity with the reaction temperature employed. The pressure of the reaction may be controlled by adjusting the amount of unreacted CHC1₂F and CF =CF₂ present in the reactor.

The reaction time, or time necessary for sufficient completion of the reaction, is somewhat dependent on the temperature chosen for the reaction, but the completion of the reaction is easily determined by the change in the pressure in the reaction vessel. Thus, if the reaction were being carried out at a given temperature under autogenous pressure, the pressure will continue to drop as the reaction proceeds and the time at which the pressure stops decreasing is taken as the end of the reaction period. Generally, the reaction time is in the range of from about 0.25 hours to about 3 hours at the preferred temperature range. The amount of modified aluminum chloride to be used, i.e., the catalytic amount, will be from about 1 to about 20 percent based on the reactant weight, preferably from about 3 to about 12 percent.

The products of the present process may be recovered by any conventional means such as by filtration or by distillation either before or after decompostion of the modified aluminum chloride by water.

In some embodiments it may be desirable to enrich the CF3CCI2CHF2 content of the reaction mixture prior to recovery. This can be accomplished by isσmerization using an alumina catalyst. In this process the reaction product is passed over a halide modified alumina catalyst at temperatures of 200 to 400°C as further described in Example 4.

The composition of C3HCI2F5 mixture may also be enriched in the CHF2CCI2CF3 component by isomerization in the liquid phase using the modified aluminum chloride catalyst prepared as described above. In this case the isomerization can be carried out by heating the mixture of the C3HCI2F5 isomers and the aluminum chloride catalyst at temperatures of 50 to 200°C under the pressure developed autogenously by the sample. The preferred catalyst is the CCl₃F-modified aluminum chloride. This procedure is further described in Example 5. The halide modified alumina catalysts suitable for isomerization of mixtures of dichloropentafluoro- propanes to enrich the 1,1,1,3,3-pentafluoro-2,2- dichloropropane content of such mixtures may be prepared in the following manner.

A quantity of alumina having a surface area greater than 100 m²/g is dried until essentially all moisture is removed, e.g., for about 18 hours at

100°C. The dried catalyst is then transferred to the reactor to be used.

The alumina catalysts can be fluorided prior to the isomerization by treatment with a vaporizable fluorine-containing fluorinating compound, such as

HF, CC1₃F, CC1₂CF₂, CHF₃, or CC1₂FCC1F₂, at elevated temperatures until the desired degree of fluorination is obtained, e.g., at about 200°C to about 450°C. By vaporizable fluorine-containing compound is meant a compound which will convert the alumina component of the catalyst to the desired degree of fluorination using pretreatment conditions which are well known to the art. The treatment with HF or other vaporizable fluorine-containing compound can conveniently be done in the reactor which is to be used for the isomerization reactions.

EXAMPLES

Example 1

Preparation of CCI3F Modified Aluminum Chloride A 500 L three neck round bottom flask was charged with 50 g (0.375 mole) of AICI3. The flask was passed out of the dry box and fitted with an addition funnel and a dry ice condenser topped with a nitrogen bubbler. The addition funnel was charged with 175 mL of CCI3F (CFC-11) and the condenser was filled with a methanol/dry ice mixture. The CFC-11 was gradually added to the flask and the mixture began to reflux vigorously. The reaction continued to reflux for an hour after all of the CFC-11 had been added. The reaction was not heated. GC analysis of the supernatant liquid indicated it was virtually pure CCl^. The volatiles were removed in vacuum and the resulting solid dried in vacuum to afford 31 g of tan powder. Analysis: Al, 28.1% (by weight) .

Example 2 Preferred Mode of the Invention CFC-11 modified aluminum chloride (13.3 g; prepared as in Example 1) was placed in a 400 mL "Hastelloy" C nickel alloy bomb. The bomb was sealed, cooled to -78°C, and purged with nitrogen three times. The bomb was evacuated once again and CHC1₂F (51.5 g, 0.50 mole) was condensed into it. The bomb was then placed in a barricade and agitated by shaking. Uninhibited tetrafluoroethylene (50 g, 0.50 mole) from a pressurized cylinder resting on a balance was added to the bomb via a remote valve. The temperature of the bomb was raised to 40°C and held at that temperature for 8 h. During this time the pressure in the bomb rose to 63 psig and gradually decreased to 35 psig. The bomb was then cooled, vented, purged and the contents poured into a jar. The crude product, weighing 111 g, consisted of a yellow supernatant over a brown gelatinous solid. The product was quenched in water and the organic layer dried over anhydrous sodium sulfate affording 65.65 g of product. Analysis of the organic layer by H NMR indicated that the following compounds were present (mole percent): 58% CHC1₂CF₂CF₃, 23% CHF₂CC1₂CF₃, 5% CHC1FCF₂CC1F₂, and 7% CHC1₂CF₂CC1F₂; no chloroform was detected. Example 3 This example shows that the reaction can be run at higher temperature without substantially affecting the results. Following a procedure similar to that of Example 2, CFC-11 modified aluminum chloride (6.7 g) and CHC1₂F (51.5 g, 0.50 mole) were reacted with tetrafluoroethylene (50. g, 0.50 mole). The reaction was held at 68-72°C for 3 hours. During this time, the pressure in the bomb rose to 83 psig, and then gradually dropped to 68 psig. Analysis of the product by H NMR indicated that the following compounds were present (mole percent): 63%

CHC1₂CF₂CF3, 24% CHF₂CC1₂CF₃, 5% CHC1FCF₂CC1F₂, 6% CHC1₂CF₂CC1F₂, and 2% CHC1₂CC1₂CF3; no chloroform was detected.

Comparative Example 1 The literature does not report CHF₂CCl2CF₃ (HCFC 225aa) as a product from CHC1₂F and tetrafluoroethylene. The following example confirms that HCFC 225aa is not formed under literature conditions. The reaction was carried out with a substantial excess of dichlorofluoromethane in the manner described by Paleta ό.; Posta, A.; Tesarik, K., Coll. Czech. Chem. Comm.. 1971, 36 (5). 1967.

A 240-mL "Hastelloy" C nickel alloy tube was charged with 5.0 g of aluminum chloride, 90 g (0.87 mol) of dichlorofluoromethane, and 30 g (0.30 mol) of tetrafluoroethylene, then agitated at about 25°C for 3 hrs. Volatile liquids, 86.4 g were transferred under vacuum from the crude reaction mixture. GC analysis showed 44.7% of the mixture, or 38.6 g (63% yield), to be the expected products, 1,l-dichloro-2,2,3,3,3-pentafluoropropane and 1,3-dichloro-l,1,2,2,3-pentafluoropropane in 75:25 ratio.

Considerable chloroform (22%) was also formed, so the mixture was fractionated in an attempt to isolate the pure propane isomers. Fractions having a boiling point range of 41-60°C were collected, and selected cuts representing the range of compositions were analyzed by NMR. The H and ¹⁹F NMR spectra confirmed the identities of the two products and also showed that 2,2-dichloro-l,1, 1,3,3-pentafluoropropane was not present. Example 4

Preparation of a C3HCI2F5 Mixture Enriched in CHF₂CC1₂CF bv Isomerization A liquid mixture of HCFC-225 isomers containing 66 mol% CHC1₂CF₂CF₃ (HCFC-225ca) , 29 mol% CHC1FCF₂CC1F₂ (HCFC-225cb) , 5 mol% CHF₂CC1₂CF₃

(HCFC-225aa) and <1 mol% CHCIFCCIFCF3 (HCFC-225ba) was passed over an alumina catalyst (Harshaw Al-3945, 4 g) in a glass tube at the rate of 1 mL/h along with nitrogen carrier gas (5 seem) . The liquid product was condensed at -78°C and analyzed by gas chromatography and ^F NMR. At 380°C the composition of the product was 70, mol% HCFC-225ca, <1 mol% HCFC-225cb, 25 mol% HCFC-225aa and 4 mol% HCFC-225ba. It is seen that the concentration of HCFC-225aa has been increased five-fold.

Example 5 Preparation of an C3HCI2F5 Isomer Mixture Enriched

A 400 L Hastelloy® nickel alloy shaker tube was charged with 33 g of a mixture of C3HCI2F5 isomers (composition of the sample below) and 6.7 g of CFC-11-modified aluminum chloride. The tube was cooled to -78°C, evacuated, and purged with nitrogen. The evacuated tube was placed in the barricade and heated to 150-161°C for 8 h; pressure was 130 psig.

The tube was then cooled, vented, purged with nitrogen and the product poured into a jar. The product consisted of a yellow supernatant over a brown solid. The supernatant was analyzed by GC and NMR. The composition of the sample was as indicated below. The analyses indicate that a substantial amount of the CHCIFCF2CCIF2 isomer was converted to the CHF₂CC1₂CF3 isomer under these conditions. In addition there was some conversion of the C3HCI2F5 isomers to C3HCI3F4 and C₃HC1₄F3 isomers.

Example 6

This example shows that the amount of catalyst can be increased without substantially changing the outcome of the reaction Following a procedure similar to that of

Example 2, CFC-11 modified aluminum chloride (13.3 g) and CHC1₂F (51.5 g, 0.50 mole) were reacted with tetrafluoroethylene (50 g, 0.50 mole). The reaction was held at 40°C for 3 hours. Analysis of the product by ^H NMR indicated that the following compounds were present: 63% CHC1₂CF₂CF3, 24% CHF₂CC1₂CF₃, 4% CHC1FCF₂CC1F₂, 7% CHC1₂CF₂CC1F₂, 2% CHC1₂CC1₂CF3; no chloroform was detected. Example 7

Preparation of CHC1₂F Modified Aluminum Chloride Reagent grade aluminum chloride (50 g, 0.37 mole) suspended in 100 mL of chloroform was stirred while 203 g (2.0 mole) of dichlorofluoro- methane was distilled in over a two hour period. Moderate cooling was used to keep the temperature below 32°C. Removal of volatiles under vacuum left 33.8 g of tan solid which was stored in a dry box. Analysis: 64.5% F (by weight). Example 8

This example demonstrates the use of CHC1₂F modified A1C1₃ as a catalyst for. the reaction of tetrafluoroethylene with CHC1₂F A 240 mL "Hastelloy" C nickel alloy bomb was charged with CHC1 F modified aluminum chloride

(5.0 g) . The bomb was evacuated and CHC1₂F (52 g, 0.50 mole), and tetrafluoroethylene (50 g, 0.50 mole) were condensed into the bomb. The bomb was agitated at 25°C for 8 hours. The crude reaction product was filtered into a cooled receiver to afford 59.6 g of product. This material was shown by GC analysis to contain 19% CHC1₂CF₂CC1F₂ and 77% of C₃HC1₂F₅ isomers; no chloroform was detected. Fractionation of the sample afforded 43.4 g of C3HC1₂F5 isomers which were analyzed by ^H and ^F NMR and shown to consist of 67% CHC1₂CF₂CF₃, 22% CHF₂CC1₂CF₃, and 11% CHC1FCF₂CC1F₂• Example 9 Preparation of CC1₂FCC1F₂ (CFC-113) Modified Aluminum Chloride

A 500 mL three neck round bottom flask fitted with a mechanical stirrer, a dropping funnel, and a 12°C reflux condenser topped with a nitrogen bubbler was charged with 44.4 g (0.333 mole) of reagent grade AICI3. CFC-113 (250 mL) was added to the addition funnel and also (50 mL) to the stirred A1C1₃; the remainder of the CFC-113 was then added rapidly. The reaction was refluxed for 1.25 h. The reaction supernatant was found to contain CF3CCI3 (CFC-113a), CCI3CCIF2 (CFC-112a), and hexachloroethane by GC and GC-MS analysis. The volatile products were removed in vacuum to afford 57.3 g of yellow powder. This material contained 13.6% Al by weight and was obviously contaminated with organic products probably CC1₃CC1₂F (CFC-111) and hexachloroethane.

Example 10

This example demonstrates the use of

CFC-113 modified aluminum chloride as the catalyst for the reaction of tetrafluoroethylene with CHC1₂F

Following a procedure similar to that of Example 2, CFC-113 modified aluminum chloride (13.3 g; prepared as in Example 8), CHC1₂F (51.5 g, 0.50 mole), and tetrafluoroethylene (50 g, 0.50 mole) were reacted at 40°C for 3 hours. During this time, the pressure in the bomb rose to 192 psig, and then gradually dropped to 158 psig. Analysis of the product by ^H NMR indicated that the following compounds were present: 47% CHC1₂CF₂CF₃, 7% CHF₂CC1₂CF₃, 22% CHC1FCF₂CC1F₂, 18% CHC1₂CF₂CC1F₂, 4% CHC1₂CC1₂CF₃, 1% 1,1,2,2,3,3,3-heptachloroρroρane, and 0.3% chloroform. Example 11 Reaction of C₃HC1₂F₅ Isomers with NaOH A mixture of C3HCI2F5 isomers (5 mL) was treated with 10 mL of 10% aqueous NaOH and the resulting two-phase mixture refluxed for 45 hours. The initial and final composition of the C3HCI2F mixture is indicated in the Table below. An additional compound was observed in the final solution; this was identified by ¹⁹F NMR as CC1₂=CFCF₃ arising from dehydrofluorination of CHC1₂CF CF₃.

Example 12 Reaction of CHC1₂F with Tetrafluoroethylene in HCFC-123

CFC-11-modified aluminum chloride (13.3 g) and HCFC-123 (60 g, 0.40 mole) was placed in a 400 mL "Hastelloy" C shaker tube. The tube was sealed and cooled to -78°C in a dry ice-acetone bath, and then alternately evacuated and purged with nitrogen three times. The tube was evacuated once again and CHC1₂F (103 g, 1.0 mole) was condensed into it. The tube bomb was then placed in the barricade and agitation begun. Uninhibited tetrafluoroethylene (19 g, 0.19 mole) was added to the bomb via a remote valve attached to a pressurized working cylinder resting on a balance. The temperature of the bomb was raised to 30°C and the pressure increased to about 120 psig^' over the course of about 1 hour. After about 1.5 hours of 5. reaction time (temperature, 34°C; pressure, 125 psig), an additional 10 g of TFE were added to the bomb. A heat kick of approximately 8°C was observed and the pressure in the bomb dropped from 134 psig to 117 psig within 15 minutes. Additional TFE was added to the 0 bomb in 4-11 g portions over the course of the next . 1.8 hours. A total of 100 g TFE had been added at this point and the pressure in the bomb decreased to 93 psig (temperature, 45°C). The temperature was held at 41-45°C for 3 hours. 5 The bomb was then cooled, vented, purged, and the contents poured into a jar. The product consisted of a clear supernatant over a viscous, brown lower layer. The crude reaction product weighed 251 g; this corresponded to a weight increase of about 177 g. 0 ¹H NMR analysis of the supernatant indicated the following composition (mole %) : CHCI2CF3, 26%; CHC1₂CF₂CF₃, 42%; CHF₂CC1₂CF₃, 8%; CHC1FCF₂CC1F₂, 16%; CHC1₂CF₂CC1F₂, 6%; CHC1₂CC1₂CF₃, 2%. No chloroform was detected by GC or ¹H NMR. 5

0

5

Claims

WE CLAIM: 1. The compound CF3CCI2CHF2•

2. A process for the preparation of hydrogen containing chlorofluoropropanes of the nominal formula C3HCI2F5 comprising contacting monofluorodichloro- methane with tetrafluoroethylene in the presence of a catalytic amount of a modified aluminum chloride catalyst containing from 3 to 68% by weight fluorine at a temperature of from 0°C to 150°C to produce a reaction product, and recovering the hydrogen containing chlorofluoropropane from the reaction product.

3. The process of Claim 2 wherein the reaction product is essentially free from chloroform.

4. The process of Claim 2 wherein the modified aluminum chloride catalyst is prepared by treating anhydrous aluminum chloride with an excess of CH3F, CH₂F₂, CHF3, CC1₂FCC1₃, CC1F₂CC1₃, CF3CCI3, CF₃CC1₂F, CF₃CC1F₂, CHC1₂CC1₂F, CHCIFCCI3, CHC1₂CC1F₂, CHC1FCC1₂F, CHF₂CC1₃, CHC1₂CF₃, CHC1FCC1F₂, CHF₂CC1₂F, CHCIFCF3, CHF₂CC1F₂, C₂HF₅, CHC1FCHC1₂, CH₂C1CC1₂F, CH₂FCC1₃, CHC1FCHC1F, CHC1₂CHF₂, CH₂C1CC1F₂, CH₂FCC1₂F, CHC1FCHF₂, CH₂C1CF₃, CH₂FCC1F₂, CHF₂CHF₂, CH₂FCF₃, CH₂C1CHC1F, CH₂FCHC1₂, CH₃CC1₂F, CH₂C1CHF₂, CH₂FCHC1F, CH₃CC1F₂, CH₂FCHF₂, CH3CF3, CH₂FCH₂C1, CH3CHCIF, CH₂FCH₂F, CH₃CHF₂, C₂H₅F, CC1₂F₂, CHC1₂F, CHC1F₂, CH₂C1F, CC1₂FCC1₂F, CC1₂FCC1F₂, CC1F₂CC1F₂, or

5. The process of Claim 4 wherein chlorofluorocarbon is selected from CC1₃F, CC1₂F₂, CHC1₂F, CHC1F₂, CH₂C1F, CC1₂FCC1₂F, CC1₂FCC1F₂ and CC1F₂CC1F₂.

6. The process of Claim 4 wherein the chlorofluorocarbon is CCI3F.

7. The process of Claim 4 wherein the chlorofluorocarbon is CHC1₂F.

8. The process of Claim 2 conducted in the presence of an inert solvent.

9. The process of Claim 7 wherein the solvent is C₃HC1₂F₅ or CF₃CHC1₂.

10. The process of Claims 2, 3, 4, 5, 6, 7, 8 or 9 wherein the hydrogen containing chlorofluoro¬ propane is CF3CCI2CHF2.

11. The process of Claim 2 wherein prior to recovery the reaction product is contacted with an alumina isomerization catalyst to enrich the CF3CCI2CHF2 content.

12. A process for enriching the CF₃CC1₂CHF2 content of a mixture of chlorofluoropropanes of the nominal formula C3HC1₂F5 comprising contacting the mixture with a halide modified alumina isomerization catalyst at temperatures between 200 to 400°C.

13. A process for enriching the CF₃CC1₂CHF₂ content of a mixture of chlorofluoropropanes of the nominal formula C3HC1₂F5 comprising contacting the mixture with a modified aluminum chloride catalyst containing from 3 to 68% by weight fluorine at a temperature of 50 to 200°C under autogenous pressure,