Method for producing fluorinated organic compounds

The vapor phase fluorination of the 2-chloro-3,3,3-trifluoropropene (1233xf)+HF→2-chloro-1,1,1,2-tetrafluoropropane (244bb) was carried out. The fluorination catalyst for the experiment was 50 wt % SbCl 5 impregnated on 50 wt % Calgon PCB activated carbon.

Several kilograms of 50 weight % SbCl 5 on activated carbon were produced in the lab. The catalyst was first passed through a 10-mesh sieve to remove fines. A total of 2272.6 grams (or about 2800 cc) was charged to two 2-inch vapor-phase pipe reactors in series and installed in a sand bath for controlled heating.

The catalyst was activated by adding a minimum of a 5:1 mole ratio of HF to SbCl 5 , followed by a Cl 2 addition of a minimum of a 3:1 mole ratio of Cl 2 to SbCl 5 . Finally, a large excess of HF was passed through the catalyst bed for 2 hours.

The reaction was run using 2-chloro-3,3,3-trifluoropropene crude raw material with various compositions as organic feed to produce 2-chloro-1,1,1,2-tetrafluoropropane. The reactor effluent was collected in a distillation column before removal of excess HF. During the experiment, a 93.5% conversion of 2-chloro-3,3,3-trifluoropropene was achieved. The maximum selectivity of 2-chloro-1,1,1,2-tetrafluoropropane achieved was 98.4% on a molar basis. The reaction ran continuously for 76.5 hrs without attempting catalyst regeneration with Cl 2 . The catalyst began showing signs of deactivation after about 65 hours on-stream time. The experimental data and reaction conditions are shown below in Tables 1A to 1D.

The liquid phase fluorination reaction of 2-chloro-3,3,3-trifluoropropene (1233xf)+HF→2-chloro-1,1,1,2-tetrafluoropropane (244bb) was carried out. The fluorination catalyst for the experiment was SbCl 5 .

About 6100 grams of SbCl 5 were contained in a Teflon™-lined liquid phase reactor (Teflon is a trademark of E.I. duPont de Nemours & Co) equipped with a 2-inch ID (inside diameter) packed column and a condenser. The reactor was 2.75-inch ID×36-inch L (length). Initially, a greater than 5:1 mole ratio of HF was added to the reactor to fluorinate the catalyst. A greater than 3:1 mole ratio of Cl 2 was then added to the reactor to ensure that the catalyst was brought back to a pentavalent state. The reactor was heated to about 85° C.-87° C. HF feed was started first. When an additional 1.3 lbs of HF had been added the 2-chloro-3,3,3-trifluoropropene feed was started. The purity of the 2-chloro-3,3,3-trifluoropropene feed stock was about 98 GC area % (gas chromatograph). The experiment ran continuously for 71 hours. For this run, chlorine was fed batchwise about every 4 hours throughout the run to keep the catalyst active. The HF and 2-chloro-3,3,3-trifluoropropene feeds were varied during the run. The feeds averaged 0.495 lbs/hr HF, and 0.408 lbs/hr 2-chloro-3,3,3-trifluoropropene (chlorine was 5.4% by weight of organic) for a 7.9/1 ratio of HF/2-chloro-3,3,3-trifluoropropene, and 135 seconds residence time at the beginning of the run. In the middle of the run, the feeds averaged 0.843 lbs/hr HF (pounds/hour) and 0.66 lbs/hr 2-chloro-3,3,3-trifluoropropene (chlorine was 3.3% by weight of organic) for a 8.33/1 ratio of HF/2-chloro-3,3,3-trifluoropropene, and 80 seconds residence time. For the end of the run, the rate was increased. The feeds for this period averaged 1.42 lbs/hr HF and 1.24 lbs/hr 2-chloro-3,3,3-trifluoropropene (chlorine was 2% by weight of organic) for a 7.5/1 ratio of HF/2-chloro-3,3,3-trifluoropropene, and 47 seconds residence time. The level of unreacted 2-chloro-3,3,3-trifluoropropene appeared to increase late in the run, which could have been the result of lower Cl 2 level or shorter residence time.

The reactor temperature range for the experiment was 78-91° C. and the pressure range was 85 psig-115 psig (pounds per square inch gauge).

The following Table 2 contains the 2-chloro-3,3,3-trifluoropropene conversion and product selectivity data:

About 5615 grams of SbCl 5 were contained in the same reactor as that of Example 2. The reactor was heated to about 85° C.-87° C. HF feed was started first. After about 1.5 lbs of HF had been added, the 2-chloro-3,3,3-trifluoropropene feed was started. The purity of the 2-chloro-3,3,3-trifluoropropene feed stock was about 97.3 GC area %. The experiment ran continuously for 71 hours. For this run, Cl 2 was fed batchwise about every 4 hours throughout the run to keep the catalyst active.

The Run # for this experiment was 36b. Conversion was immediately above 98%, and remained that way throughout the rest of the run (through Friday shut-down). The catalyst charge was left hot over the weekend, and operation resumed on Monday (now called Run #37), and similar high conversion was observed throughout the week. About 123 pounds of acid-free 2-chloro-1,1,1,2-tetrafluoropropane crude was collected between runs #36b and its continuation as Run #37 the following week.

The reactor temperature range for the experiment was 78° C.-86° C. and the pressure range was 70 psig-105 psig. The organic crude material collected from the run was run on a gas chromatograph and exhibited the following GC analysis.

The following Tables 3A and 3B set forth the 2-chloro-3,3,3-trifluoropropene (1233xf) conversion and product selectivity data.

Liquid-phase Catalytic Fluorination of CF 3 CCl═CH 2 (1233xf) with HF to CF 3 CFClCH 3 (244bb)

About 327 grams of HF, about 50 grams 1233xf, and about 75 grams SbCl 5 were charged into a 1-L autoclave. The reaction mixture was stirred at a temperature of about 80° C. for about 3 hours under about 620 psig of pressure. After the reaction, the reactor was cooled to about 0° C. and about 300 ml water was then added slowly into the autoclave over a period of about 45 min. After complete addition of water under stifling, the reactor was cooled to room temperature and then the overhead gases were transferred to another collecting cylinder. The yield of CF 3 CFClCH 3 was about 90% at a 1233xf conversion level of about 98%. The other major by-products were CF 3 CF 2 CH 3 (2%), and an unidentified isomer of a C4 compound of the general formula, C 4 H 3 Cl 3 F 4 (8%).

Liquid-phase Catalytic Fluorination of CF 3 CCl═CH 2 (1233xf) with HF to CF 3 CFClCH 3 (244bb)

About 327 grams HF, about 50 grams 1233xf, and about 75 grams SbCl 5 were charged into a 1-L autoclave. The reaction mixture was stirred at 80° C. for about 3 hours under about 625 psig of pressure. After the reaction, the reactor was cooled to about 45° C. and then the overhead gas mixture was passed through a well dried KF, NaF, or Al 2 O 3 (350 g) packed column kept at about 80° C. to strip off HF from the gas stream. The gases coming out of the column are collected in a cylinder kept in dry ice (−70° C.) bath. The yield of CF 3 CFClCH 3 was 87% at a 1233xf conversion level of 93%. The other major by-products were CF 3 CF 2 CH 3 (1%), and an unidentified isomer of a C4 compound of the general formula, C 4 H 3 Cl 3 F 4 (7%). The product, CF 3 CFClCH 3 was isolated by distillation with 98% purity.

Gas-phase Catalytic Fluorination of CF 3 CCl═CH 2 (1233xf) with HF to CF 3 CFClCH 3 (244bb)

A 22-inch (½-inch diameter) Monel tube gas phase reactor was charged with about 120 cc of a catalyst. The reactor was mounted inside a heater with three zones (top, middle and bottom). The reactor temperature was read by a custom made 5-point thermocouple kept at the middle inside of the reactor. The inlet of the reactor was connected to a pre-heater, which was kept at about 300° C. by electrical heating. Organic (1233xf) was fed from a cylinder kept at 70° C. through a regulator, needle valve, and a gas mass-flow-meter. The organic line to the pre-heater was heat traced and kept at a constant temperature of about 73° C. by electrical heating to avoid condensation. N 2 was used as a diluent in some cases and fed from a cylinder through a regulator and a mass flow controller into the pre-heater. All feed cylinders were mounted on scales to monitor their weight by difference. The reactions were run at a constant reactor pressure of from about 0 to about 100 psig by controlling the flow of reactor exit gases by another research control valve. The gas mixtures exiting reactor was analyzed by on-line GC and GC/MS connected through a hotbox valve arrangements to prevent condensation. The conversion of 1233xf was from about 50% to about 65% and the selectivity to 244 isomer (CF 3 CFClCH 3 ) was from about 90% to about 93% depending on the reaction conditions using 120 cc of 50 wt % SbCl 5 /C as the catalyst at about 65° C. to about −85° C. with a HF flow of about 50 g/h and organic flow of about 15 g/h. No CF 3 CF 2 CH 3 was observed under the reaction conditions. The catalyst is pretreated at first with 50 g/h HF at about 65° C. for about 2 hours and then with about 50 g/h HF and about 200 sccm of Cl 2 at about 65° C. for about 4 hours. After pre-treatment, about 50 sccm of N 2 is flows over a period of about 40 minutes through the catalyst bed to sweep free chlorine from the catalyst surface prior to interacting with the organic feed (1233xf). Pretreatment is considered important to many embodiments of the invention. The products were collected by flowing the reactor exit gases through a 20-60 wt % aqueous KOH scrubber solution and then trapping the exit gases from the scrubber into a cylinder kept in dry ice or liquid N 2 . The products were then isolated by distillation. About 50 wt % SbCl 5 /C, about 3 to about 6 wt % FeCl 3 /C, 20 wt % SnCl 4 /C, and about 23 wt % TiCl 4 /C, using 4 different kind of activated carbon such as Shiro saga, Calgon, Norit, and Aldrich were used as the catalyst at from about 60 to about 150° C. Among all the catalysts used for this reaction, Cl 2 and HF pre-treated SbCl 5 /C was found to be generally preferred in terms of activity. The results using SbCl 5 as the catalyst are shown in Table 2.

It should be understood that the foregoing description is only illustrative of the present invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims.