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Dec. 10, 1946. G, A_ |BAcH ETAL ' 2,412,220 TREATMENT OF FLUORINE-CONTAINING HYDROCARBON MIXTURES Filed Jan. >3, 1944 - u HOLVNOLLOVt-id r X HBMOJ. BdOBlOEIZV INVENTORS G. A. iBACH 8- C.C. TATE stung”?ATTORNEYS M In...‘ Patented Dec. 10, 1946 2,412,220 ' UNITED’ STATES PATENT. OFFICE ~ 2,412,220 _ TREATMENT or FLUORINE-CONTAINING . HYDROCARBON mxTunEs - Gerald A. Ibach, Borger, Tex., and Carmen C. Tate, Okmuigee, 0kla., asslgnors to Phillips Petroleum Company, a corporation of Delaware Application January '3, 1944, Serial No. 516,868 5 Claims. (Cl. 196-41) The present invention relates to the treatment of hydrocarbon materials and more particularly to the removal from such materials of ?uorine oontaining compounds, both organic and inor game, which may be present therein as a result of treatment with hydrogen ?uoride, concen trated hydro?uoric acid or boron tri?uoride which ' range of approximately 70° to 550° F. Superat mospherio pressures, for example, such as are re quired to maintain the material being treated in the liquid phase, may be used, although the proc ess may be conducted in the vapor phase at nor mal pressures. Instead of bauxite, alumina gels, chromium oxide, zirconium oxide, magnesium ox ide and calcium oxide and oxides of metals of the were used to facilitate polymerization, allryla iron group, especially ?nely divided nickel de tion or other reactions. posited on an inert support,.may be used. The The use 01 hydrogen ?uoride, hydro?uoric acid 10 reactions which occur with said metal oxide are and boron tri?uoride and solutions of boron tri not clearly understood but some of the organic ?uoride in water as catalysts for the polymeriza ?uorine-containing compounds are probably de tion of unsaturated hydrocarbons‘ and for the . alkylation oi hydrocarbons with unsaturated hy composed to hydrogen ?uoride. Any hydrogen ?uoride present therein or formed in the treat-1 drocarbons has been widely adopted. Such proc» 15 ment reacts'with the bauxite'to form nonvolatile esses are described, for example, in Frey Patents compounds with the‘bauxite and some hydrogen No, 2,322,800 and 2,317,901 and also in the arti ?uoride may react‘ with any silica that may vbe cles by Frey‘ in Chemical and Metallurgical Engi present in‘ the bauxite to produce silicon tetrafiu neering, 1943, vol. 50, pages 126 to 128 (November, oride or hydro?uosilicic acid, which remains in 1943) and Philnews, December, 1943, pages '1 to 20 the hydrocarbon material. 10. After treatment of hydrocarbon-containing In conducting such a process as described in mixtures therewith these catalysts must be re said copending application of Frederick E. Frey moved. The removal of the greater portion of the bauxite. or other metal oxide may become these catalytic materials from the treated prod - vspent, either partially or completely, during the ucts is a relatively simple matter but many un 25 operation, in which event the organic ?uorides foreseen di?iculties arise in attempting to e?ect will not be completely or will be but incompletely the complete removal of these ?uorine-containing removed. It channeling occurs in the bed of catalysts and any ?uorine-containing compounds metal oxide, the removal may also be incomplete. which result from side reactions. Furthermore, if any hydro?uoric acid or com It is an object of the present invention to pro 30 pound which vis capable of liberating hydrogen vide a process for the substantially complete re ?uoride or hydro?uoric acid is present in the ma moval of small residual amounts of ?uorine-con ‘terial being treated, it may be unremoved or may taining compounds from hydrocarbons and hy- ' be but partially removed in this manner. drocarbon-containing mixtures that ‘have been If the bauxite which is being used for the treat treated with hydrogen ?uoride, hydro?uoric acid, 35 ment contains silica, as.most bauxite samples boron tri?uoride or compositions containing generally do, hydro?uoric acid or hydrogen ?uo-' them. ' ride, if present originally or if formed during the It is a further object of the invention to provide~ treatment, may react with such silica and form such a. process which is simple and economical. silicon tetra?uoride or hydro?uosilicic acid which 40 Other objects of the invention, some of which may be left in the hydrocarbon. Also, if the con are more speci?cally referred to hereinafter, will ditions of temperature, pressure and ?ow rate‘ be apparent to those skilled in the art to which are not adjusted properly, the treatment with the invention pertains. bauxite or other of the speci?ed metal oxides may In the copending application of Frederick E. be only partially effective and may be accom 45 Frey, Serial No. 398,361, ?ied June 16, 1941 (Pat panied by such reactions whereby organic fluo-_ ent No. 2,347,945 issued February 15, 1944) is dis rides together with hydrogen ?uoride, silicon tat-, closed a process of removing residual amounts of ra?uoride or other inorganic ?uorides appear ‘or organic ?uorine compounds from a mixture of are formed and appear in the product of the para?in hydrocarbons containing such organic treatment. The process of the present invention 50 ?uorine compounds, which comprises subjecting is directed to the prevention or avoidance of any said mixture to the action of a solid porous metal of these di?lculties which may arise in the de oxide such as bauxite, which is catalytically active ?uorination'of hydrocarbon materials. for hydrogenation and dehydrogenation reac It has been observed during the course of con tions, under suitable conditions. Such condi tions include reaction temperatures within the 55 tinued operation of such a de?uorination process, aeiaaao 4 in which the material after treatment with baux ite is subjected to fractional distillation, that a coating, cake or deposit of solid'matter accumu lates in the fractional distillation apparatus and azeotrope tower 2. This hydrocarbon charge may _ be the hydrocarbon materials which are formed in a polymerization or an alkylation process, for example, it may be the alkylate resulting from that the pipes orv conduits ‘through which the 5 the treatment of isobutane ‘with a butene-con treated material circulates become clogged with such deposits. The apparatus, which is usually of iron or other metal also‘ becomes corroded. . taining C4 hydrocarbon fraction or a pure butene in the presence of liquid hydrogen ?uoride to pro duce isooctane, orany reactions comprising hy dro?uoricacid as catalyst. Besides the desired 10 ‘product, the hydrocarbon material will normally contain unalkylated low boiling hydrocarbons and dissolved or entrained liquid hydrogen ?uoride The source of this deposit, which contains an ap preciable quantity of silica, is evidently the sili con tetraiviuoride, silicic and/or ?uosllicic acids in the de?uorinator eiiluent, and which are probably formed from siliceous matter present in the baux or other catalytic material and organic ?uorine ite or other-naturally occurring metal oxides. Al compounds. _ though the amount of this deposit is negligible at 15 The hydrocarbon ‘charge is subjected to frac the start of operations, it becomes greater as the bauxite becomes spent and as the treatment pro grasses. - tional distillation in azeotrope tower 2. The over- 4 head fraction of the distillation is discharged at ' ’ 3 and normally consists of a mixture of the low Some of the aforesaid difficulties are partially boiling hydrocarbons and liquid hydrogen ?uoride obviated by using a series of bauxite chambers, 20 as an azeotropic mixture. This overhead frac and so operating that the material leaving the tion or distillate may be sent to an acid settler or treaters or chambers comes into contact in the similar device for separating the hydrocarbons from the hydrogen ?uoride, which generally sep arate when the distillate is'gcon'densed. These last chamber of the series with fresh bauxite. Such operation is costly, however, and uneconom ical of bauxite, and, furthermore, requires care 26 separated materials may be returned or recycled ful control and frequent observation. , to the reactor or alkylator and reused. The bot v In accordance with our invention, the foregoing tom fraction which is substantially devoid of free di?lculties‘are entirely obviated, or obviated to a or uncombined hydrogen ?uoride as a result of great degree, by subjecting the hydrocarbon material that has been treated with bauxite or other metal oxide to treatment with sodium hy droxide or other alkaline solution and then to ?l tration through an essentially. non-siliceous. granular ?ltering medium before being subjected to distillation. I ‘ . The ?ltering medium must, of course, be resist ant to the action of alkaline solutions and be non packing so that it is pervious to liquids and gases the distillation is charged through conduit 4 to bauxite treater 5. In the event that the hydro carbon material is substantially free of hydrogen ?uoride or concentrated hydro?uoric acid, the treatment or distillation in the azeotrope tower may be omitted and the hydrocarbon material 35 charged directly to‘the bauxite treater. The treatment with bauxite or other porous metal oxide which is catalytically active for hy drogenation and dehydrogenation reactions is conducted in bauxite treater Ii substantially as and may be readily wetted by aqueous liquids. Suitable ?ltering media are anthracite coal, pe 40 described in the copendingapplic'ation of Fred troleum coke, wood charcoal, and the like, which erick E. Frey, Serial No. 398,361 (Patent No. may contain small amounts of silica but which - 2,347,945 issued February 15, 1944), Thus the are essentially nonsiliceous. A metal ?lter, such temperature of the treatment may be within the as screenings or turnings of copper, silver, Monel range of approximately 70° to approximately 550° metal or other metals or metal alloys that are 46 F. and the pressure may be sufilcient ‘or greater not aifectedby hydro?uoric acid, may also be than that necessary to maintain the material in used. The function of the ?ltering medium is to liquid phase. Although one bauxite treater is remove any droplets of aqueous alkaline solution represented in the drawing, preferably two or which may be entrained or carried over or be more are used and they are generally of such. present in the hydrocarbon being treated. when 60 capacity that su?lcient de?uorination is eil'ected. siliceous ?ltering media are used, they may be These treaters are also arranged so that the come clogged by the action of the alkaline solu material passes through that containing the most ' tion on the silica. When the sodium hydroxide solution becomes spent or its circulation to the - active or least spent treating agent last and pro vision is preferably made for recharging the‘ ' washing unit is stopped, deposits of solids may 65 treaters sOythat operations will not tinued while one is being recharged. be disconf contact of the hydrocarbon material containing The treated hydrocarbon material then passes fluorine compounds with a siliceous ?ltering ma ‘through conduit 8 to tower 1 which is a washing terial whereby silicon compounds are formed and and'?lterin'g tower provided with baffles 8 and in ‘form in the fractionating unit as a result. of the , are carried over with the hydrocarbon. Aqueous solutions of sodium hydroxide are the preferred treating solutions. Howevensolutions of potassium-hydroxide, sodium carbonate, so-v dium bicarbonate, potassium carbonate, borax or similar alkaline substances or mixtures thereof, in water or other solvents, may be used, although their effectiveness for the purpose may be'some what less than that of an aqueous solution of which‘?ltering material 8 is disposed“ The wash ing medium, which may be sodium hydroxide or caustic soda solution or one of the other mate rials hereinbefore referred to, is charged to tank III through inlet II. After tank It) and the wash ing system are ?lled, su?‘lclent material is added at inlet I I to compensate for that withdrawn from tank III through outlet valve I2. ‘The wash liquid is pumped from tank III by means of pump I 3 through conduit I4 and into tower ‘I through a The accompanying drawing is .a ?ow diagram or spray IE or other suitable distributing of a process that is a preferred embodiment of 70 nozzle device. Thede?uorinated hydrocarbon material our invention. In this preferred process, the hy - that has been treated with bauxite or other de sodium hydroxide. . drocarbon layer remaining after the separation of liquid hydrogen ?uoride or concentrated hy ?uorinating agent in treater I passes up through 'the tower ‘I where it is washed with the sodium ‘ dro?uoric acid is charged through inlet I to an 75 hydroxide solution and is then ?ltered through ' 9,412,220 which are capable of engendering silicon tetra ?uoride or hydro?uosilicic acid in contact with materials used in earlier stages of the process. Thus, the process of the invention is also applica ble to- the'treatment of hydrocarbon materials containing boron ?uoride,. which may be present the bed of ?ltering material 9. It is then charged through conduit 16 to fractionator IT. The ?lter ing material is preferably granular > anthracite coal or coke or other essentially nonsiliceous granular filtering medium as hereinbefore de scribed. The bed should be of a thickness suffi as a result of the use of boron ?uoride or hydro cient to remove substantially all entrained wash ?uoric acid containing boron ?uoride as catalysts, ing solution. ‘ or the treatment of hydrocarbon materials con In the event that the hydrocarbon material is taining alkyl ?uorides or other organic ?uorides “ not contacted with the washing solution, any sili 10 that may be unstable to heat or to materials used con tetra?uoride or hydro?uosilicle acid may be in the de?uorination process. > , condensed on the ?ltering material and thus will The process of the invention has been described not pass through to the fractionator. Further particularly in connection with a hydrocarbon more, if hydrogen ?uoride is left in the hydro 15 alkylation process, that is, a process in which one carbon material after the washing treatment, no silicon tetra?uoride which might be carried over into the fractionator will be formed in the ?lter. The presence of hydrogen ?uoride in the frac tionator is less detrimental than the presence of silicon tetra?uoride. hydrocarbon is alkylated with another hydro carbon and more speci?cally in which an all phatic para?in hydrocarbon is alkylated with an ‘ ole?n hydrocarbon. .However, it is to be under- ' 20 stood that it is applicable generally to ei?uents of the treatment of any alkylatable hydrocarbon, The concentration of the washing solution may saturated or unsaturated, aliphatic, aromatic or ' be varied over a wide range, dependent upon the amount of puri?cation required, and the capacity cycloaliphatic, with an alkylating reagent, name ' . ly, unsaturated hydrocarbons, halides or alcohols, of the washing tower ‘I, the degree of circulation and that the term allnvlation includes polymeri ‘of the solution and the intimacyof the contact 25 zation. It can also be used to treat eiiluents of between the hydrocarbon material and the solu isomerization processes in which hydro?uoric tion. Ordinarily an aqueous solution containing from 1 to approximately 20% by weight or more acid is used as a catalyst. Generally the hydrocarbon material which will of sodium hydroxide is used. The temperature be subjected to treatment with alkaline solutions of the washing treatment may also be varied‘over 30 according to the process of the invention will be a wide range, being normally between approxi in liquid phase but it is obvious that the process mately 30° to approximately 200° F. and prefer is capable of being used for the treatment of hy ably between 60° and 100° F. drocarbon materials in gaseous or vapor phase ' Fractionator I1 and subsequent’fractionators not shown separate the total hydrocarbonsinto in known manner. Inasmuch as the foregoing speci?cation is merely illustrative and comprises preferred em . required recycle and e?luent products of the proc ess. The overhead product leaves the fractiona ‘ bodiments of the‘ invention it is to be understood ‘tor ll through outlet l8 and the kettle product - that the invention is not limited thereto and that , through outlet l9, and :these may be either ?nal modi?cations maybe made therein and alterna yield or recycle streams or intermediate streams 40 tives substituted for certain of the described pro requiring further separation, as is evident to one cedures without departing substantially from the invention as de?ned in the appended claims. ‘ skilled in the art. It is to be understood that the foregoing de scription is merely illustrative, that the drawing is merely a diagrammatic representation of the We claim: 45 ' ‘ -1. In a process for treating hydrocarbon ma terials containing minor amounts of ?uorine now of materials in the process, and that the ac compounds as impurities by contact with a baux-' tual apparatus which will be required may in ite containing siliceous material under conditions clude heaters, pumps, valves (some of which are such that ?uorine is retained by said bauxite and represented), pressure gauges,‘ ?ow meters, heat tetra?uoride-is formed from such siliceous exchangers, re?ux accumulators, surge tanks, 60 silicon material, the improvement which comprises, and other conventional equipment whichwill be passing a hydrocarbon material eilluent from understood by those skilled in the art to whichv such a treatment with such a bauxite, and con the invention pertains. taining said silicon tetra?uoride, into the bottom ‘ It is further contemplated that the apparatus will be constructed of metals and other materials 55 of a puri?cation zone comprising a lower contact ing zone and an upper ?ltration zone, passing an which are inert or resistant to hydro?uoric acid aqueous solution of sodium hydroxide to the top and/or other substances which are used in con of said contacting zone and contacting same tact with the apparatus. Such materials of con therein with said hydrocarbon material to dis struction are described in the article by Charles solve said silicon tetra?uoride therein, and pass 60 M. Fehr, “Materials of construction for anhy ing said hydrocarbon material upwardlythrough drous hydrofluoric acid" in Chem. Met. Eng, said. contact zone and subsequently upwardly , 1943, vol. 50, page 129 (November, 1943) and in through said ?ltration zone to remove entrained the articles of Frey referred to hereinbefore. sodium hydroxide solution. Although the foregoing process has been de-= 2. In a process for treating hydrocarbon mate scribed particularly in connection with de?uori 65 rials containing minor amounts of ?uorine com nation of hydrocarbon materials that have been produced or treated with liquid hydrogen ?uoride pounds as impurities by contact with a bauxite or concentrated hydro?uoric acid catalysts, it is containing siliceous material under conditions applicable generally to the treatment of all hy such that ?uorine is retained by said bauxite and drocarbon materials which contain ?uorine-con 70 silicon tetra?uoride is formed from such siliceous taining compounds capable of engendering hy drogen ?uoride or hydrofluoric acid by hydrolysis or by thermal decomposition or decomposition in the presence of bauxite or other materials with material, the improvement which comprises, passing a hydrocarbon material eiliuent from such a treatment with such a bauxite, and con which the hydrocarbon material is contacted or 76 taining said silicon tetra?uoride, into contact 2,412,920, with an aqueous solution of sodium hydroidde to ‘remove said silicon tetra?uoride by . solution therein. ' > > ' - 3. In a process for treating hydrocarbon ma teriais containing minor amounts of ?uorine taining said silicon‘ tetra?uoride, into contact with‘ an aqueous alkaline solution. to remove said silicon tetra?uoride by solution therein. ‘ _ 4. The process of claim 1 in which said ?ltra tion zone contains a granular carbonaceous ma compounds as impurities by contact with a baux terial selected from the group consisting 01’ an ite containing siliceous material under conditions thracite coal, petroleum coke and wood charcoal. 5. The process ofv claim 1 in which said ?ltra such that ?uorine is retained by said bauxite and silicon tetra?uoride is formed from such siliceous ‘material, the improvement which comprises, passing a hydrocarbon material é?iuent from such a treatment- with such a bauxite, and con ' 10. tion zone contains granular anthracite coal. GERALD ‘A. mom .7 CARMEN c.v 'rn'ra.