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'itti tires 3,048,629 Patented Aug. 7, 1962 l 2 3 048,629 tained through carbonization of the raw material followed by an activation step which involves the controlled oxida PREPARATION 61F FLllJQRQSULFUR COMPOUNDS Kenneth Vincent Martin, Wilmington, Del., assig‘nor to tion of the carbonized material. The preparation of active carbon is well-known in industry and a number of active E. I. du Pont de Nemours and Company, Wilmington, Del‘, a corporation of Deiaware o No Drawing. Filed Apr‘ 29, 1959, Sen No_ 809,598 5 Clainm carbons are commercially available. . A large variety of ?uorooletins may be employed in the (CL 269M544) process of the present invention to prepare thiocarbonyl compounds. Depending on the number of carbon atoms The process of the present invention relates to the in the ?uoroole?n and the location of the unsaturated preparation of sulfur-containing, ?uorinated compounds, 10 bond, the products are either thioacetyl ?uorides or thio and, more particularly, to the preparation of ?uorinated ketones. In terminally unsaturated ?uoroole?ns, the thiocarbonyl compounds from ?uorinated ole?ns. ketones are formed in preference to the acetyl ?uorides. Fluorothioacetyl halides and ?uorothioketones are a The ?uoroole?ns employed may be branched, cyclic, or novel class of chemical compounds which show outstandinternally unsaturated. As indicated by the general ing technical promise as monomers for the preparation 15 formula hereina-bove, it is not essential that all of the of thermally stable and corrosion-resistant elasto-mers. substituents on the double bond the ?uorine or ?uoro Low molecular weight liquid polymers of these comcarbon radicals. Representative examples of the ?uoro pounds have properties which make them suitable for use ole?ns are tetra?uoroethylene, hexa?uoropropylene, per as dielectric media, hydraulic ?uids and inert solvents. ?uorobutene-l, per?uorobutene~2-, per?uoroisobutylene, It is, therefore, the principal object of the present in- 20 per?uoropentene-l, per?uoropentene-Z, omega-hydroper vention to provide a method for the preparation of ?uoro?uoropentene-l, per?uorooctene-l, per?uorododecene-l, thiocarbonyl compounds. omega - hydroper?uoroheptene - 1, per?uorocyclobutene, The object of the present invention is accomplished by per?uorocyclohexene, tri?uoroethylene, chlorotri?uoro a process which comprises contacting a mixture of a ethylene and the like. The preferred starting materials ?uoroole?n having the general formula 25 employed in the process of the present invention are those R2 having the general formula CF2=CF—CI,F2,,X, where n A} is from 0 to 10 and X is selected from the class consisting R‘TC: "R3 of ?uorine and hydrogen. The ratio of the sulfur to the ?uoroole?n is not critical; wherein R1 and R3 are the same or different radicals 30 howe‘fefi it is Preferred to emPlQY at least equal molar selected from the class consisting of ?uorine, per?uoroquanti?es Ofsulfur and the ?uoTPole?n- _ _ carbon radicals and divalent ?uorocarbon radicals formed The Process of lbs Present Invention 15 further mus‘ from the combination of R1 and R3, and R2 is a radical t1" ated by the ‘followmg examples selected from the class consisting of hydrogen, halogen EXAMPLES I TO VI and per?uorocarbon radicals, and vaporized sulfur at a 35 The attached table demonstrates the preparation of temperature of 250° C- tO 750° C-r but pl'?fel‘ably at thiocarbonyl compounds in accordance with the present a temperature 05 350° C- to 450° C» With activated invention and shows the conditions and results employed carbon, and recovering a ?uorothiocarbonyl compound. in each example_ vaporized Sulfur, obtained by heating In accordance the present invention, the ?uorothioSulfur in a Stainless ‘steel vessel and passing nitrogen Carbonyl ‘Compounds are Obtained by Passing a miXtUI‘e 40 through the molten sulfur, is admixed with the ?uoroole 0f vapofiz'id Sulfur and the ?u?mole?n through an 805?n indicated, and passed into a 1 in. nickel tube placed vated carbon bed maintained at the temperatures indiin an upright position in a tube furnace, The ?ow of c?tefl- The P1"0C6§S may be Can'ied 011i With an inel-“l gas sulfur was regulated by the temperature of the sulfur pot Camel”, 311611 35 nltfog?n 01' any of the rare gases- The _ and the ?ow in the nitrogen. The tube contained a 7 contact time of the gas mixture with the carbon should ‘in in. packed bed of activated carbon, “Cheney CH-Z,” be long enough to alloW the gas to Come ‘to the term commercially available from the Barnaby Cheney Corp., pcratllre 0f the active Carbon bed- Th6 ?IlOIO‘thiOCB-Fheated by the tube furnace to the temperature indicated. bonyl compounds obtained are caught in a cold trap and The effluent gas was passed into a cold trap maintained at are then puri?ed by distillation. F —78° C. which condensed the thiocarbonyl products Any type of active carbon can vbe employed as the ‘)0 formed. The thiocarbonyl products were isolated and catalyst in the present invention. In ‘general, however, puri?ed by distillation from the cold trap‘. Table I Example Fluoroole?n Flow Rate, nil/mm. Temp. of Flow Sulfur Rate of Vessel, ° C. Carbon Bed Reaction Nitrogen Temp., ml./min. Product Time ° C. tetratluoro- 150 422 150 422 120 min_ 8 ml. of tri?uorothloacetyl ._-_.do _____ _. ehlorotri?uoroethylene. 150 150 420 440 150 150 500 480 240 min. 30?ml._ ‘(11f tri?uorothioacetyl 180 min. 64 lgmofe.ehlorodi?uorothio acetyl ?uoride. per?uoro~ 150 420 100 470 240 min. 9.8 g. of per?uorothiophane tri?uoro‘ ethylene. 150 420 150 400 120 min. ditluorothioaeetyl ?uoride. hexa?uoro- 150 440 160 370-450 ethylene. glfécbu» propylene. active carbon prepared from wood, sawdust, peat, lignite and pulp-mill waste is preferred. Active carbon is ob ?uoride. a-thione. 4hrs.___ 130 g. hexa?uorothioaeetone, HgIéIlIGXS?UOI‘OthiOZLCGtOHB The examples set forth are illustrations of the invention described and are not to be construed as limiting the 3,048,629 3 4 of 350° C. to 450° C., a mixture of vaporized sulfur and a ?uoroole?n having the general formula invention. Various modi?cations of the process equip ment will be apparent to those skilled in the art and are included in the scope of the present invention. The proc ess described provides an economic and ready manufac where in is an integer from 0 to 10 and X is from the ture of ?uorothiocarbonyl compounds from ?uoroole?ns class consisting of hydrogen and ?uorine, with active and sulfur. I claim: carbon. 3. The process as set forth in claim ‘1 wherein the ole 1. A process for the preparation of ?uorothiocarbonyl compounds which comprises contacting at a temperature ?n is chlorotri?uoroethylene. 4. The ‘process as set forth in claim 1 wherein the of 250° C. to 750° C., a mixture of vaporized sulfur and 10 a non-aromatic ?uoroole?n having the general formula ?uoroole?n is tetra?uoroethylene. 5. The process as set forth in claim 1 wherein the ?uoroole?n is hexa?uoropropylene. 15 wherein R1 and R3 are radicals selected from the class consisting of fluorine, ?uorocarbon radicals and divalent ?uorocarbon radicals formed from the combination of R1 and R3, and R2 is a radical selected from the class consisting of hydrogen, ?uorine, chlorine, and ?uorocar bon radicals, with active carbon. 2. A process for the preparation of ?uorothiocarbonyl compounds which comprises contacting at a temperature References Cited in the ?le of this patent UNITED STATES PATENTS 2,922,816 2,962,529 Bruce ______________ __ Jan. 26, 1960 Marquis ____________ __ Nov. 29, 1960 OTHER REFERENCES Brandt et 211.: J. Chem. Soc. (London), vol. of 1952, page 2201. Lovelace: “Aliphatic Fluorine Compounds,” page 222 (1958).