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Patented May 31, 1949 2471,525

UNITED STATEs.2,471,525 PATENT . . . OFFICE. REACTION OF AN WITE EF TO PRODUCE WNYL FLUORDE AND/OR DFLUoRoETHANE AND HOMOLOGUES. THEREOF John C. Hillyer and Joseph F. Wilson, Bartlesville, Okla., assignors to Philips Company, a corporation of Delaware No Drawing. Application December 19, 1947, Seria No. 92,832 11 Claims. (C. 260-653) 1 2 This invention relates to the reaction of an of a reacting mixture passes up through it, or acetylene with . In one aspect as a flowing stream of small, or even powdery, it relates to an improved process for the produc fluent particles, moving through a reaction Zone. tion of . In another aspect the in The reaction is exothermic, and some suitable, vention relates to an improved process for the conventional means should be used to maintain a production of 1,1-difluoroethane. In a broader desired reaction temperature and take up heat aspect the invention relates to an improved proc of reaction. The acetylene reactant may be acet :ess for producing difluorohydrocarbons. . ylene, itself, or some homologue of higher molec The direct noncatalytic interaction of acet ular weight, preferably one having not more than ylene with hydrogen halides to produce vinyl O ten atoms per . halides is well known. However, this method . The product obtained from the reaction of acet of procedure, particularly when applied to the ylene itself comprises vinyl fluoride and 1,1-di hydrofluorination of an acetylene, is too ineffi fluoroethane in substantially equal proportions. cient, both as regards rate of reaction and yield Each of these materials has important uses in (of product, to have commercial significance. Cat s the chemical industries, and each can be read alysts such as mercuric oxide or mercuric halide ily recovered from the reaction products. Vinyl have been employed to activate the interaction of fluoride, heretofore in short supply due to the acetylene with other hydrogen halides, particu lack of a suitable method for its preparation, larly . However, attempts to has valuable applications in the production of use these catalysts for the hydrofluorination of 20 synthetic resins; 1,1-difluoroethane has valuable acetylene have resulted in numerous difficulties, -properties as a refrigerant, a propellant for aero Such as long induction periods before the reac sol-type insecticide sprays, and the like. When tion begins, poor yields of product, rapid deterio an acetylene of a higher number of carbon atoms ration of the catalyst, and the like. per molecule is reacted, the proportion of di We have discovered a process for the hydro 25 fluoro product is higher, and tends to become fluorination of an acetylene wherein the catas the sole primary reaction product. In Such a case lyst employed comprises aluminum trifluoride, both atoms become attached to the same aluminum oxide, or mixtures of these materials. carbon atom, which is generally the more cen When operating according to our process, induc- . tral, in the molecule, of the two initially-avail tion periods are short, reaction rates are high, 30 able, carbon atoms. The reaction mixture may and catalyst is long. The degree of utiliza- - contain only the two reactants or, if desired, may tion of the acetylene is high and increases as the contain a diluent which is inert under the reac reaction proceeds, becoming substantially quan tion conditions, such as , , Carr titative after a few hours. bon tetrafluoride, etc. : An object of this invention is to provide an 35 The aluminum trifluoride catalyst of our in improved process for the interreaction of an acet vention is preferably prepared in the form of ylene and . pellets, by the use of small amounts of a binder Another object of this invention is to produce such as graphite, hydrogenated corn oil, and the vinyl fluoride. like. However, when desired, the aluminum tri . A further object of this invention is to produce 40 fluoride may be deposited on a carrier such as 1,1-difluoroethane. alumina, a bauxite high in alumina and with a ... Still a further object of this invention is to low silica content, etc., or may be combined with produce difluoro derivatives of paraffin hydro materials such as activated carbon to provide . highly effective results. Further objects and advantages of this inven The mechanism by which Our aluminum oxide tion will become apparent, to one skilled in the catalysts operate is not entirely clear. It may art, from the accompanying disclosure and dis be possible that small amounts of an aluminum CuSSion. - fluoride, such as aluminum-oxyfluoride, in a high : In accordance with our invention, an acetylene 1y active state is formed on the catalyst surface. is mixed with hydrogen fluoride and contacted SO However, if such a change in the initial aluminum with the catalyst. The catalyst is preferably in oxide occurs, the quantity of such an aluminum -a granular or pulverulent form, and may be em fluoride is exceedingly small. A granular mates ployed either as a fixed bed of coarse catalyst rial which is aluminum oxide initially is a good granules, as a single bed of Small, even powdery, catalyst for the reaction herein discussed, how fluent particles in ebullient motion as a stream sever, whatever the source of the catalytic ac 2,471,525 3 4. tivity, and the above suggestion is offered merely reaction was halted. During the reaction 167.2 for general interest. liters of acetylene was charged, 5.2 liters of which Before contacting with the reactants the cat- was recovered unreacted. alyst is preferably dried by heating, in the cat- Fractionation of the product provided 180 cc. of alyst case, in a stream of inert gas. In the prac- 5 vinyl fluoride (B. P-72.2°C.) and 160 cc. of 1,1- tice of our process the acetylene and hydrogen difluoroethane (B. P.-24 C.), the remainder fluoride are mixed, preferably with a molar excess being dissolved acetylene. of hydrogen fluoride, in a ratio of up to about Eacample II fifteen mols of hydrogen fluoride (HF) to one mol ple of acetylene , and passed over the 10 Tne procedure of Example I was repeated catalyst at a temperature between 350 and 750 F., using similar feed stock and reaction conditions. preferably between 450 and 650 F. The flow rate After 32 hours Operation the temperature in the of the reaction mixture should be between 150 catalyst zone was reduced to 500 F. to observe and 400, preferably between 200 and 300 vol- whether catalyst activity would continue when so umes (standard conditions) per volume catalyst 5 operating. The yield per hour continued to in per hour. Pressures will, in general, be substan- crease for a period of eight hours at which time tially atmospheric, although values somewhat the run Was discontinued. above or below this level, such as up to about 50 Eacomple III pounds per square inch gage, may be employed, p when desired. At the beginning of each run a 20 A steel tube, was charged with 200 cc. of pel short induction period is usually observed with leted aluminum oxide. The tube was then heated aluminum trifluoride, generally from about ten to at a temperature of 600°F. for six hours to dry about 30 minutes in length, although there is the catalyst, moisture being swept from the tube substantially no induction period with aluminum by a stream of dry nitrogen. Acetylene and hy oxide. 25 drogen fluoride were commingled, in a mo) ratio Efluent from the catalyst Zone is treated to re- of 1:1.54, and passed over the catalyst at a rate of cover various constituents. In such a separa- 142.5 volumes per volume of catalyst per hour. tion, the effluent may be treated to separate hy- Effluent gases were passed through a steel tube drogen fluoride, as by being passed over sodium containing , to remove unreacted fluoride, after which it is condensed and frac- 30 hydrogen fluoride, after which they were con tionated to separate an olefinic , densed in a Dry Ice-cooled trap. and/or a difluorohydrocarbon. Unreacted acet- At the end of eight hours the proportions uf ylene reactant may be recycled and, if only a acetylene and hydrogen fluoride were changed to difluoro hydrocarbon is desired, the olefinic provide a mol ratio of 1:1.62 and the run con monofluoride produced may be returned for 35 tinued for 6.5 hours. Ratios of feed materials and further reaction. flow rates were altered from time to time and the In the following examples, the data are pre- volume of . product determined as the reaction sented as being typical of the invention, and such proceeded until the catalyst had been used for a data should not be construed to limit the inven- total of 38.5 hours. Data on the entire operation tion unduly. 40 are shown in the accompanying table.

Average Time. Mol Ratio Flow Rate Contact. Avg. Yield 1 Unreacted Tenp.OF. Hrs. p CH:HF w/v.IHrs. TimeSec. catalystcc.fcc. PerCH, Cent

600 8.0 11.54 i42.5 ii. 4 0.098 28.2 600 6.5 : 62 79.0 9.5 O. 119 29.8 600 8.0 1:1. 57 198.5 8.5 0.136 28.8 600 8.0 1:2.43 317.5 5.2 0.89 25.6 600 8.0 1:11 85. 0 8.9 0.17 22.3 Yield based on total liquid product. Fractionation showed this product to comprise 44.7 per cent (average value) vinyl fluoride and 40.6 percent 1.1-difluoro . The remainder, 14.7 per cent was found to be dissolved acetylene. No 1,2-difluoroethane was isolated. Eacample I Eacample IV A steel tube was charged with 200 cc. of a pel- 55 Hydrogen fluoride and 1- were mixed, in leted catalyst comprising 93.6 per cent of alu- a mol ratio of hydrocarbon to hydrogen fluoride minum trifluoride and 6.4 per cent of flake 1:12.5, and passed over a pilled catalyst compris graphite used as a binder. The catalyst was ing aluminum trifluoride together with a small heated for two hours at a temperature of 600 F. amount (6.5 per cent) of a graphite binder. The in a current of nitrogen to remove moisture. space velocity was about 500 volumes per volume Acetylene and hydrogen fluoride were then mixed, catalyst per hour and the temperature was 450°F. in a mol ratio of 1 to 2.24, and passed over the Upon fractionation of the product it was found catalyst at a rate of 332.5 volumes per volume of that a Conversion of 1-hexyne to 2,2-difluorohex catalyst per hour, the temperature being held at s ane of about 85 per cent had been obtained. 600 F. Efluent gases were passed through a steel tube containing sodium fluoride to remove unre- Eacample V acted hydrogen fluoride, after which they were The procedure of the run of Example IV was condensed in a dry ice Cooled trap. repeated, using 1- as reactant. The mol After an induction period of 15 minutes liquid ratio of the acetylene to HF was 1:1.49, the space condensate began to collect in the trap, the rate 70 velocity of the reactants was 383 volumes per vol gradually increasing over the entire period. After ume of catalyst per hour, and the reaction tem eight hours the average condensation amounted to perature was 450° F. Conversion of the acetylene 47.6 cc, per hour. The catalyst activity showed to 2,2-difluoropentane was 42.1 volume per cent no apparent diminution after the eight hour pe- in a single pass, with an ultimate yield of 84 per riod, the degree of conversion increasing until the cent based on recycle Operation. 2,471,525 5 6 As will be evident to those skilled in the art, effluents of said reaction zone an addition product various modifications of this invention can be of said acetylene and hydrogen fluoride. made, or followed, in the light of the foregoing 6. An improved method of reacting an acetylene disclosure and discussion, without departing from having not more than ten carbon atoms per mole the spirit or scope of the disclosure or from the Cule and hydrogen fluoride to produce an addition Scope of the claims. product, which comprises admixing hydrogen We claim: fluoride and such an acetylene in a mol ratio be 1. An improved method of reacting acetylene tween 1:1 and 15:1, passing said admixture into and hydrogen fluoride to produce an addition a reaction zone containing a solid aluminum Oxide product, which comprises admixing hydrogen O Catalyst, maintaining in said reaction Zone a re fluoride and acetylene in a mol ratio between action temperature, between 350 and 750 F., 1:1 and 15:1, passing said admixture into a re maintaining a flow rate of said reactants into action Zone containing a solid catalyst of the Said reaction Zone between 150 and 400 volumes per Volume of catalyst per hour, and recovering group consisting of aluminum fluoride and alu minum oxide, maintaining in said reaction zone a 5 from effluents of said reaction zone an addition reaction temperature between 350 and 750 F., product of said acetylene and hydrogen fluoride. maintaining a flow rate of said reactants into said 7. An improved method for reacting an reaction zone between 150 and 400 volumes per acetylene and hydrogen fluoride, which comprises volume of catalyst per hour, and recovering from contact’ng a mixture comprising an acetylene and effluents of said reaction zone an addition product a molar excess of hydrogen fluoride with a solid of acetylene and hydrogen fluoride. 20 catalyst comprising a catalytic material of the 2. An improved method of reacting acetylene group consisting of aluminum fuoride and and hydrogen fluoride to produce an addition aluminum oxide at an elevated reaction tempera product, which comprises admixing hydrogen ture, whereby hydrogen fluoride adds to said fluoride and acetylene in a mol ratio between 1:1 25 acetylene, and recovering a resulting fluoro and 15:1, passing said admixture into a reaction hydrocarbon. Zone containing a solid aluminum fluoride cata 8. An improved process for the production of lyst, maintaining in said reaction zone a reaction vinyl fluoride, which comprises admixing acetyl temperature between 350 and 750° F maintain ene and a molar excess of hydrogen fluoride, pass ing a flow rate of said reactants into said reaction 30 ing a resulting mixture into contact with an Zone between 150 and 400 volumes per volume of aluminum fluoride catalyst at a temperature catalyst per hour, and recovering from effluents between 450 and 650 F. and a space velocity of of Said reaction zone an addition product of 200 to 300 volumes per volume of catalyst per acetylene and hydrogen fluoride. . hour, and recovering from effluents of said reac 3. An improved method of reacting acetylene tion vinyl fluoride so produced. and hydrogen fluoride to produce an addition 9. An improved process for the production of product, which comprises admixing hydrogen vinyl fluoride, which comprises admixing and acetylene in a mol ratio between 1:1 ene and a molar excess of hydrogen fluoride, pass and 15:1. passing said admixture into a reaction. ing a resulting mixture into contact with an Zone containing a solid aluminum oxide catalyst, aluminum oxide catalyst at a temperature be maintaining in said reaction zone a reaction tem tween 450 and 650 F. and a space velocity of 200 perature between 350 and 750 F. maintaining a to 300 volumes per volume of catalyst per hour, flow rate of said reactants into said reaction zone and recovering from effluents of said reaction between 150 and 400 volumes per volume of cata vinyl fluoride so produced. lyst per hour, and recovering from effluents of 45 10. An improved process for the production of Said reaction zone an addition product of acet 2,2-difluoroethane, which comprises admixing ylene and hydrogen fluoride. acetylene and a molar excess of hydrogen fluoride, 4. An improved method of reacting an acetylene passing a resulting mixture into contact with an having not more than ten carbon atoms per mole aluminum fluoride catalyst at a temperature be cule and hydrogen fluoride to produce an addition. tween 450 and 650 F. and a space velocity of product, which comprises admixing hydrogen 200 to 300 volumes per volume of catalyst per fluoride and such an acetylene in a mol ratio be hour, and recovering from effluents of said re tween 1:1 and 15:1, passing said admixture into a action 2,2-difluoroethane so produced. reaction Zone containing a solid catalyst of the 11. An improved process for the production of group consisting of aluminum fluoride and alumi 55 2,2-difluoroethane, which comprises admixing num oxide, maintaining in said reaction zone a acetylene and a molar excess of hydrogen fluoride, reaction temperature between 350 and 750° F, passing a resulting mixture into contact with an - maintaining a flow rate of said reactants into said aluminum. Oxide catalyst at a temperature be reaction zone between 150 and 400 volumes per tween 450 and 650 F. and a space velocity of volume of catalyst per hour, and recovering from 60 200 to 300 volumes per volume of catalyst per hour, effluents of said reaction zone an addition product and recovering from effluents of said reaction of said acetylene and hydrogen fluoride. 2,2-difluoroethane so produced, 5. An improved method of reacting an acetylene - JOHN C. B.Y.E.R. having not more than ten carbon atoms per mole JOSEPH. F. WSON. cule and hydrogen fluoride to produce an addition 65 product, which comprises admixing hydrogen REFERENCEs CITED ... fluoride and such an acetylene in a mol ratio be The following references are of record in the tween 1:1 and 15:1, passing said admixture into a file of this patent: . reaction zone containing a solid aluminum fluo ride Catalyst, maintaining in said reaction zone a 70 UNITED STATES PA reaction temperature between 350 and 750 F., Number Name Date maintaining a flow rate of said reactants into said 2,118,901 Soll ------May 31, 1988 reaction zone between 150 and 400 volumes per 2,401,850 Whitman ------June 11, 1946 volume of catalyst per hour, and recovering from 2,437,148 Barney ------Mar. 2, 1948