April 6, 1948, R. S. HOVEY ETAL 2,439,299 PRODUCTION OF HALOGENATED HYDROCARBONS CONTAINING FLUORINE Filed July 26, 1946

wr vir - INVENTORS - ult R. S. HOVEY U d t P. H. CARNELL U W1 BY

M ATTORNEYs / Patented Apr. 6, 1948 2439,299

UNITED STATES PATENT OFFICE

PRODUCTION OF BALOGENATED BY ORO CARBONS CON ANNG FUORNE Roger S. Hovey, Charleston, W. War, and Paul H. Carneli, Bartlesville, Okla, assignors to Philips Petroleum Company, a corporation of Delaware Application July 26, 1946, Seria No. 686,374 12 Claims. (CI. 260-653) 2 This invention relates to the production of Or kanes that are valuable as refrigerants and dis ganic fluorine compounds, more particularly persants. In addition to having properties that fluorinated hydrocarbons. In a more specific aS make them suitable as refrigerants and dispers pect it relates to the production of halogenated ants, these compounds have faint, nonobjection hydrocarbons containing fluorine and another able odors and are nontoxic and noninflammable. halogen from halogenated hydrocarbons contain Several fluorochloroalkanes used as "refrigerants ing a plurality of atoms of halogen other than are listed in the following table: fluorine. In one aspect it relates to the produc tion of mixed fiuoro-chloro-methane and -ethane fron corresponding chlorinated hydrocarbons, for 0. Formula Trade example the production of dichlorodifioroneth Name ane and/or trichloromonofluoromethane from -29.8 Freon, carbon tetrachloride, dichloromonofluoronethane 23.7 F-11 from chloroform and dichlorotetraiuoroethane CICEF 8.9 F-21. from hexachloroethane. 5 CsClaF---- 3. F-14, The principal object of the present invention is to fuorinate hydrocarbon derivatives. Another Our investion is a process of producing halo object is to replace organically bound chlorine, genated hydrocargo as, particularly the alkanes bromine and/or iodine atoms with fluorine atoirs. and especially the lower alkanes such as methane Another object is to produce fluorinated hydro 20 and ethane, containing fluorine and another hal carbon derivatives. Another object is to produce ogen, which comprises contacting a halogenated organic fiuorine compounds useful as refriger hydrocarbon containing a plurality of atoms of ants and dispersants. Another object is to pro halogen other than fluorine With a fluorinating wide a novel fuorinating agent. Another object agent comprising 8, major proportion of substan is to provide an improved method of manufac 25 tially anhydrous hydrofluoric acid and a minor turing dichlorodifiuoromethane. Another object proportion of titanium tetrafluoride under con is to provide an improved method of producing ditions such that at least one, but usually less . trichloromonofluoromethane. Still another ob than all, of said atoms of halogen other than ject is to provide an improved method of pro fluorine is replaced with fluorine. ducing dichloromonofluoromethane. Another 30 For example in accordance with one embodi object is to provide an improved method of mak ment of our invention, dichlorodifluoromethane, ing dichlorotetrafluoroethane. Many other ob CCl2F2, and/or trichloromonofluoromethane, jects will more fully appear from the following de CCl3F, are prepared by treating carbon tetrachlo Scription. ride with a fluorinating agent comprising sub The accompanying drawing portrays diagram stantially anhydrous hydrofluoric acid containing matically one specific embodiment of the present 35 a minor proportion of titanium tetrafluoride. invention. The drawing is a simplified flow di Similarly, dichloromonofluoromethane may be agram. Of One arrangement of apparatus for pro produced from chloroform, and dichlorotetra ducing dichlorodifiuoromethane from carbon fluoroethane may be produced from hexa tetrachloride. 40 chloroethane in accordance with our invention. Broadly the present invention comprises treat These examples are illustrative only and are by ing organic chlorine, bromine and/or iodine com no means exclusive, since our invention may be pounds with a novel fluorinating agent to replace employed to effect replacement of any number of halogen atoms of these compounds with fluorine. atoms of halogen other than fluorine in a halo The novel fluorinating agent of this invention 45 genated hydrocarbon with fuorine. Our inven comprises substantially anhydrous hydrofluoric tion is chiefly applicable to replacement of chlo acid containing a minor proportion of titanium rine with fiuorine. However, it may be employed tetrafluoride. The titanium tetrafluoride acts as to replace bronine and/or iodine with fluorine. a promoter for the hydrogen fluoride, the mixture The fluorinating agent of the present invention functioning as a new and improved catalyst in an 50 comprises a major proportion of substantially an old reaction, it being old to use other promoters, hydrous hydrofluoric acid and a minor proportion particularly antimony halides, in conjunction of titanium tetrafluoride. Usually the catalyst with hydrofluoric acid in this type of reaction. consists essentially of, i. e. the only active ele Among the products obtainable by the process ments of the catalyst are, hydrogen fluoride and . of this invention are low-boiling fluoro-chloroal 5. titanium tetrafluoride. 2,489,299 3 4 The proportions of hydrogen fluoride and ti substantially anhydrous or completely anhydrous tanium tetrafluoride employed may vary within conditions. By "substantially anhydrous" we wide limits. The preferred concentration of ti mean the presence of not more than about 1.0 tanium tetrafluoride in the fluorinating agent is Weight per cent of water in the reaction zone. from 1 to 10 weight per cent based on the weight Numerous types of apparatus are suitable for of titanium tetrafluoride and hydrogen fluoride. carrying out our invention. Mechanically-agi Concentrations of titanium tetrafluoride outside tated or jet agitated contactors may be used, or these limits may, however, be used if desired. It the halogenated hydrocarbon may be dispersed is ordinarily not desirable to use less than 1 per and allowed to rise through the body of the cat cent of titanium tetrafluoride because the pro 0 alyst. Intimate contacting of the catalyst and moting action at such concentrations is not suffi the reactant is desirable. In many cases the cient. More than 10 per cent of titanium tetra reaction mixture will comprise two phases. fluoride may be used if desired. For example con namely, a hydrofluoric acid phase and a halo centrations ranging from 10 per cent up to 50 per genated hydrocarbon phase, and it will be nec cent of titanium tetrafluoride, based on the 5 essary to provide means for intimately contact weight of titanium tetrafluoride plus hydrogen ing these two phases. fluoride, may be used. Ordinarily, however, the While our invention may be carried out in a promoting action is not sufficiently enhanced by batchWise manner, we prefer continuous oper the use of concentrations of titanium tetrafluo ation. Continuous operation may be practiced ride above 10 per cent to make use of such con 20 by continuously charging to a suitable pressure centrations economically feasible. In fact the resisting vessel the original halogenated hydro promoting activity appears to be as great within carbon and the fluorinating agent of our inven the 1 to 10 per cent range as it is at Concentrations tion, maintaining these materials under reac above 10 per cent. tion conditions for a suitable length of time, The reaction temperature employed may vary continuously withdrawing from the reaction over wide limits. We use temperatures above at zone the resulting reaction mixture, continu mospheric and We prefer to use temperatures Ously recovering the fluorinated hydrocarbon within the range of from 50 to 200° C. Likewise product and recycling unreacted and partially the pressure used may vary widely but is prefer reacted material as well as catalyst to the reac ably sufficiently high to maintain the reaction 30 tion Zone. Any conventional apparatus for Con mixture in the liquid phase, Ordinarily the pres ducting reactions involving anhydrous or Sub sure is such that substantially all of the react stantially anhydrous hydrofluoric acid, such as ants and reaction products are maintained in the equipment commonly used for alkylating the liquid phase. The pressure required to isoparaffins with olefins with this acid, may be accomplish this will depend upon the temper 35 used. Suitable recycle arrangements for the ature and the proportions of the various ingre fluorinating agent, for unreacted materials, and dients charged to the reaction zone. The reac for other components of the reaction effluent may tion is ordinarily carried out in a closed pres be provided as desired. sure-resisting vessel of such size that the ma In one embodiment of our invention which is jor proportion and usually substantially all of 40 especially desirable in continuous operation, the the materials are in the liquid phase. The rela fluorinating agent of Our invention is prepared tive amounts of materials in the liquid phase by adding titanium tetrachloride to liquid an and in the gas space thereabove will depend upon hydrous hydrofluoric acid which converts the the relative volumes of the reaction vessel and titanium tetrachloride to the tetrafluoride in the liquid charge. In view of the much greater 45 situ. Since titanium tetrachloride is normally concentration of material in the liquid phase a liquid, whereas titanium tetrafluoride is nor than in the gaseous phase, nearly all may be in mally a solid, difficulties occasioned by the ad the liquid phase even though the reaction ves dition of a solid to a liquid under pressure are sel has a volume several times larger than the thus obviated. When this mode of operation is volume of the liquid charge. 50 employed, the titanium tetrachloride and the While liquid phase operation is preferred, op hydrofluoric acid are preferably separately in eration with the reactants and/or reaction prod troduced to the reaction zone. The proportions ucts and catalyst in the gas phase is within the of the hydrofluoric acid and the titanium tetra scope of our invention in its broader aspects. chloride should be such that after reaction of The reaction time during which the reactants 55 all of the titanium tetrachloride with the hydro are contacted with the fluorination agent will fluoric acid to form titanium tetrafluoride there depend upon a number of factors including the is present a major proportion of hydrofluoric particular raw material and the specific product acid and a minor proportion of titanium tetra desired. In general a contact time of from 5 fluoride. The titanium tetrafluoride goes into to 25 minutes is satisfactory. the liquid phase under the conditions employed. Although the ratio of fluorinating agent to 60 This may be due to the use of a temperature halogenated hydrocarbon in which fluorine sub above the melting point of titanium tetrafluo stitution is to be effected, may vary within a ride in the reaction zone, but it is probably due wide range, it is preferably greater than 1:1 by mainly to the fact that the titanium tetrafluoride weight. It may range from such a ratio up dissolves in the hydrofluoric acid as rapidly as wardly to as high as i0:1 or even higher. How 65 it is formed. However both factors may be in ever economic considerations may prevent or Wolved. make undesirable use of a range greater than While formation of titanium tetrafluoride "in say 7:1 or 8:1. situ' in the manner just described is often pre While the present description gives directions. ferred, preparation of fluorinating agent of our which will enable any person skilled in the art O invention by direct mixing of titanium tetra to practice our invention, optimum reaction fluoride, and hydrofluoric acid is within the in conditions for obtaining a given product from a tended Scope of Our invention. given reactant can readily be determined by trial. Referring to the accompanying drawing, car Ordinarily our invention is carried out under 75 bon tetrachloride and anyhydrous hydrofluoric 2489,299 5 acid containing a minor proportion of titanium had the characteristic faint odor of dichlorodi tetrafluoride are passed to a reactor via lines fluoromethane, 2 and 3, respectively. In reactor f these con Many advantages are obtained by means of ponents are intimately contacted under the re the present invention. The invention provides action conditions previously described. The a simple, economical and effective way of produc conditions are preferably so controlled that prod ing fluorinated hydrocarbons, particularly the ucts more highly fluorinated than dichlorodi mixed fluoro-chloro-alkanes typified by di fluoromethane are not obtained in substantial chlorodifluoromethane, dichloromonofluorometh amounts. The reactor effluent is passed via line ane, and dichlorotetrafluoroethane. The use of 4 to a fractionator or series of fractionators des O titanium tetrafluoride as a promoter is advanta ignated by reference numeral 5, from which are geous as compared with the antimony halides withdrawn a low-boiling fraction comprising hy which have been used heretofore, Titanium drogen chloride leaving via line 6, an interme tetrafluoride is cheap since it can be made from diate fraction comprising dichlorodifluorometh titanium tetrachloride. Yields are better and the ane, the chief product of the process, leaving via 5 process is more clean Cut when titanium tetra line 7, and a kettle residue comprising hydro fluoride is used than when the antimony halides fluoric acid, titanium tetrafluoride, and unreact of the prior art are employed to promote the hy ed or incompletely reacted material. This kettle drofluoric acid. Many other advantages of my residue is withdrawn via line 8 and may be with invention will be obvious to those skilled in the art drawn from the system via line 9 but preferably from a consideration of the foregoing description. is recycled, at least in part via line O to the We claim: reactor . 1. The process of producing halogenated hy If it is desired to form titanium tetrafluoride drocarbons containing fluorine and another "in situ' in the manner described above, titanium halogen which comprises contacting a halogen tetrachloride and anhydrous hydrofluoric acid are 92.5 ated hydrocarbon containing a plurality of atoms separately introduced to the reactor via lines of halogen other than fluorine with a fluorinat 3 and f, respectively. ing agent comprising a major proportion of sub If the proportions of the materials fed to re stantially anhydrous hydrofluoric acid and a actor are such that two phases exist in the ef minor proportion of titanium tetrafluoride under fluent, it may be passed via line 2 to a settling SO conditions such that at least one of said atoms zone 3 where it is settled into a hydrofluoric acid of halogen other than fluorine is replaced with phase which may be recycled to reactor via line fluorine. 4 and a halogenated hydrocarbon phase which 2. The process of producing halogenated hy may be passed via line 5 to the fractionation sys drocarbons containing fluorine and another hal tem 5. 35 Ogen which comprises contacting a halogenated In an alternative arrangement the reactor ef hydrocarbon containing a plurality of atoms of fluent may be passed to a flash chamber (not halogen other than fluorine with a fluorinating shown) in which a mixture of hydrogen chloride agent comprising a major proportion of substan and dichlorodifluoromethane are flashed from tially anhydrous hydrofluoric acid and from 1 to the reactor effluent. The dichlorodifiuorometh 4) 10 weight per cent, based on the weight of tita ane is subsequently freed of hydrogen chloride nium tetrafluoride and hydrofluoric acid, of tita by fractionation and/or washing with alkali, or nium tetrafluoride under conditions such that at in any other suitable manner. least one, but less than all, of said atoms of hal In still another alternative arrangement, hy ogen other than fluorine is replaced with fluorine. drogen chloride and dichlorodifluoromethane are 45 3. The process of producing halogenated hy separately removed from the reactor effluent by a drocarbons containing fluorine and another hal two-stage flashing Operation. ogen which comprises contacting a halogenated It may often be desirable to pass a portion or hydrocarbon containing a plurality of atoms of all of the separated catalyst to purification or re halogen other than fluorine with a fluorinating generation step wherein the catalyst is recovered agent consisting essentially of a major proportion in pure form for recycle to the reactor. In this of substantially anhydrous hydrofluoric acid and way the gradual loss of activity of the catalyst from 1 to 10 weight per cent, based on the weight which normally occurs may be counteracted. of titanium tetrafluoride and hydrofluoric acid, The regeneration may be conducted in any suit of titanium tetra, fluoride under conditions such able way, as for example by distilling of HF and SS that at least one, but less than all, of said atoms other products and recovering the HF in any suit of halogen other than fluorine is replaced with able way, and recovering TiE4 from the residue by fluorine. extraction, volatilization or the like. 4. The process of producing halogenated hy drocarbons containing fluorine and another hal Eacample ogen which comprises contacting a halogenated A 1.5-liter Monel bomb was charged with 525 hydrocarbon containing a plurality of atoms of grams of anhydrous hydrofluoric acid, 30 grams halogen other than fluorine with a fluorinating of titanium tetrafluoride, and 160 grams of car agent consisting essentially of substantially an bon tetrachloride. The bomb was then closed hydrous hydrofluoric acid and from 1 to 10 weight and heated to 127° C. by means of an external 85 per cent, based on the weight of titanium tetra electric heater, and the contents were agitated fluoride and hydrofluoric acid, of titanium tetra for 15 minutes by the use of a platform rocker. fluoride at a temperature of from 50 to 200° C. Throughout the treatment the bomb remained and under other conditions such that at least one, but less than all, of said atoms of halogen other closed and the pressure was allowed to build up. 70 than fluorine is replaced with fluorine. Most of the material remained in the liquid phase. 5. The process of producing halogenated hy At the end of the reaction period, part of the drocarbons containing fluorine and another hal organic material was removed from the bomb Ogen which comprises contacting a halogenated and distilled. About 60 volume per cent boiled hydrocarbon containing a plurality of atoms of in the range of -30 to '--25° C. This fraction 75 halogen other than fluorine with a fluorinating 2,439,299 7 8 agent consisting essentially of substantially an prises contacting hexachloroethane with a fluo hydrous hydrofluoric acid and from 1 to 10 weight rinating agent consisting essentially of substan per cent, based on the weight of titanium tetra tially anhydrous hydrofluoric acid and from 1 to fuoride and hydrofluoric acid, of titanium tetra 10 Weight per cent, based on the weight of ti fluoride at a temperature of from 50 to 200 C. tanium tetrafluoride and hydrofluoric acid, of and an elevated pressure sufficient to maintain titanium tetrafluoride at a temperature of from liquid phase for a period of time such that at 50 to 200° C. and a pressure sufficient to main least one, but less than all, of Said atoms of tain liquid phase for a period of time such that halogen other than fluorine is replaced with four of the atoms of chlorine in said hexachloro O ethane are replaced with fluorine to form di fluorine.6. The process of producing halogenatedw hy chlorotetrafluoroethane, drocarbons containing fluorine and another hal 11. The process of producing dichlorodifluoro ogen which comprises contacting a halogenated methane which comprises subjecting a mixture hydrocarbon containing a plurality of atoms of consisting of 525 parts by weight of anhydrous halogen other than fluorine with a fluorinating 5 hydrofluoric acid, 30 parts by weight of titanium agent consisting essentially of substantially an tetrafluoride, and 160 parts by weight of carbon hydrous hydrofluoric acid and from 1 to 10 weight tetrachloride to agitation at a temperature of per cent, based on the weight of titanium tetra 127 C. in a closed pressure-resisting reaction fluoride and hydrofluoric acid, of titanium tetra vessel at a pressure such that substantially all of fluoride at a temperature of from 50 to 200°C. 20 the material is maintained in the liquid phase, and at an elevated pressure sufficient to main for a period of time of 15 minutes, and recover tain liquid phase for a period of time of from ing dichlorodifluoromethane from the resulting 5 to 25 minutes such that at least one, but less reaction mixture. than all, of said atoms of halogen other than 12. In a process of producing halogenated hy fluorine is replaced with fluorine. 25 drocarbons containing fluorine and another hal 7. The process of claim 6 wherein the ratio of ogen which comprises contacting a halogenated said fluorinating agent to said halogenated hy hydrocarbon containing a plurality of atoms of drocarbon containing a plurality of atoms of halogen other than fluorine with a fluorinating halogen other than fluorine is greater than 1:1 agent consisting essentially of a major proportion by Weight. 30 of Substantially anhydrous hydrofluoric acid and 8. The process of producing dichlorodifluoro a minor proportion of titanium tetrafluoride in methane which comprises contacting carbon a reaction Zone" under conditions such that at tetrachloride with a fluorinating agent consisting least one of said atoms of halogen other than essentially of substantially anhydrous hydro fluorine is replaced with fluorine, the improved fluoric acid and from 1 to 10 weight per cent, 35 method of introducing said titanium tetrafluoride based on the weight of titanium tetrafluoride and into the reaction zone which comprises forming hydrofluoric acid, of titanium tetrafluoride at a it in situ by separately introducing liquid sub temperature of from 50 to 200° C. and a pressure stantially anhydrous hydrofluoric acid and liquid sufficient to maintain liquid phase for a period titanium tetrachloride into the reaction zone, the of time of from 5 to 25 minutes, the ratio of said 40 proportions of said hydrofluoric acid and said fluorinating agent to said carbon tetrachloride. titanium tetrachloride being such that upon re being greater than 1:1 by Weight, and thereby action of all of said titanium tetrachloride with effecting replacement of two atoms of chlorine in hydrofluoric acid to form titanium tetrafluoride said carbon tetrachloride with two atoms of fluo there is present a major proportion of hydro rine to form dichlorodifluoromethane. 45 fluoric acid and a minor proportion of titanium 9. The process of producing dichloromono tetrafluoride. , fluoromethane which comprises contacting chlo Y ROGER. S. HOWEY. roform with a fluorinating agent consisting essen PAUL. H. CARNELL. tially of substantially anhydrous hydrofluoric acid and from 1 to 10 Weight per cent, based 50 REFERENCEs CITED on the weight of titanium tetrafluoride and hy . The following references are of record in the drofluoric acid, of titanium tetrafluoride at a file of this patent: temperature of from 50 to 200° C. and a pressure sufficient to maintain liquid phase for a period UNITED STATES PATENTs of time such that one of the atoms of chlorine 55 Number - Name Date in said chloroform is replaced with fluorine to 1930,129 Midgley et al. ------Oct. 10, 1933 form dichloromonofluoromethane. . 2007,208 Midgley et al. ------July 9, 1935 10. The process of producing dichlorotetra 2,062,743 Daudt et al.------Dec. 1, 1936 fluoroethane from hexachloroethane which com ---