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Home , Fluorine, Fluorine compounds

Patented June 5, 1945 2,377.546 UNITED STATE s PATENT of FICE 237,546 PROCESS FOR TREATING Y DROCARBON CONTANNG ORGANICA Y COMBINED FLUOR NE Frederick E. Frey, Bartlesville, okia, assignor to Phillips Petroleum Company, a corporation of Delaware No Drawing. Application August 30, 1943, Serial No. 500,553 5 Claims. (C. 196-44) The present invention relates to a method of alysts are used. Another object is to provide a removing Organic from ma method for the liberation of terials and more particularly from hydrocarbon from hydrocarbon materials containing organic materials which contain organic fluorine as a re fluorine and fixation of so sult of having been prepared by processes involv liberated. Numerous other objects will herein ing use of fluorine-containing catalysts, such as after appear. trifluoride but more especially hydrogen In accordance with the present invention, the fluoride. removal of organic fluorine from hydrocarbon This application is a continuation-in-part of materials containing the same is accomplished my prior and copending application Serial No. 0 by treating the hydrocarbon material with alu 398,361 filed June 16, 1941, now Patent No. 2,347,- nina impregnated with an alkali compound 945 issued May 2, 1944. capable of combining with hydrogen fluoride, Hydrogen fluoride is finding use to an increas effecting decomposition of the organic fluorine ing extent as a catalyst in hydrocarbon conver compounds present in the hydrocarbon with con sons, especially alkylation of paraffins with ole 5 sequent liberation of hydrogen fluoride and con fins to make motor and aviation fuel compo bination of the hydrogen fluoride so liberated nents of high anti-knock rating. It is also be with the compound carried by the ing used as a treating and refining agent for alumina, The decomposition of the organic notor and aviation fuels and lubricating oil, The is effected by the employ crude hydrocarbon products obtained by such 20 ment of elevated temperatures in the treatment, processes contain substantial amounts of organ other conditions being such as to favor this de ically combined fluorine which must be removed composition and combination of the hydrogen in order to meet specifications. Products made fluoride set free with the alkali metal compound. with other fluorine-containing catalysts, chief Preferably the temperature lies between 150 and among which is , likewise con 26 550 F. tain combined organic fluorine. The alumina may be in any form which is Hydrocarbon materials that have been pre sufficiently adsorbent to allow impregnation pared by processes of the foregoing type in which with the alkali metal compound. Usually and fluorine-containing catalysts are used contain preferably the alumina is in the form of either small proportions of organic fluorine in the form 30 bauxite or activated alumina. This alumina is of organic compounds which are believed to be impregnated with from approximately 2 to ap predominantly alkyl and/or aryl . Here proximately 10% by weight of the alkali metal tofore this organic fluorine has been removed by compound, and any moisture is removed, where passing the hydrocarbon material through a upon the resulting material is then ready for porous contact material of the type of activated 85 use in carrying out the invention. alumina or bauxite. Unfortunately, however, As the alkali metal compound I may employ contact materials of this type may contain up to any alkali metal compound which is capable of so much as 20 per cent by weight of silica, which combining with hydrogen fluoride. The pre apparently reacts with formed ferred alkali metal compound is the alkali hy by decomposition of the organic fluorine com 40 droxide. Instead of the I may en pounds to form tetrafluoride. This sili ploy any alkali metal salt or compound which con tetrafluoride is highly objectionable because is capable of combining with hydrogen fluoride. contact of it with moisture liberates hydrofluoric It is preferred to use an alkali metal compound acid which is exceedingly corrosive, and at the which combines with the hydrogen fluoride to same time deposits gelatinous silicic acid which 45 give the alkali acid fluoride. For example, one accumulates until the equipment is plugged, mol of the alkali metal hydroxide reacts with Moreover the resultant loss of fluorine in the two mols of HF to give the alkali metal acid fluo ride and one mol of water. One mol of alkali form of is economically un metal fluoride reacts with One mol of FH to desirable.The principal object of the present invention is- 30 give the alkali acid fluoride directly. ACCOrd to provide for the removal of organic fluorine ingly, the alkali metal compound which is pref from hydrocarbon materials containing the same. erably and almost invariably employed will be Another object is to remove organic fluorine from . either the alkali metal hydroxide or the alkali hydrocarbon materials that have been prepared metal fluoride. In some circumstances it may be by processes in which fluorine-containing cat- 65 found possible or desirable to use the alkali metal

s 2 2,877,546 . Use of alkali metal carbonate or bicar step. The resulting regenerated contact mass bonate is ordinarily not desirable because of the which comprises bauxite and fluoride liberation of CO2 which contaminates the hy is then reused for removing additional organic drocarbon stream. As the alkali metal. I prefer fluorine. to employ the more common and potas While specific details of the preferred mode Of sium although the use of lithium is not precluded. operation have been given in the foregoing for Potassium is preferred. The other alkali , purposes of illustration, it is to be understood that cesium and rubidium, although operative, are the invention is not limited thereby, but is to be prohibitively expensive and are not used. The taken as limited solely by the language of the term “alkali metal' as used herein, therefore, O appended claims. comprehends the true, alkali metals found in 1. A process for treating hydrocarbon contain I of the periodic system, and does not in ing organically combined fluorine to remove said clude ammonium. fluorine therefrom which comprises subjecting By the treatment of the present invention, said hydrocarbon containing a minor quantity of the organic fluorides contained in the hydrocar organically combined fluorine to the action of de bon are decomposed, forming in part hydrofluoric hydrated adsorbent silica-containing alumina acid which reacts with the alkali metal hydroxide impregnated with an alkali metal fluoride at a re or fluoride, preferably potassium hydroxide or action temperature of from 150 to 550°F, and for fluoride, to form the alkali metal acid fluoride, a of time such that said alumina catalyzes preferably potassium acid fluoride, before it re decomposition of the organic fluorine compounds acts with the silica in the alumina. When the present in the hydrocarbon with consequent liber alumina impregnated with the alkali metal Com ation of the fluorine as hydrogen fluoride and pound has become spent, passage of hydrocarbon combination of hydrogen fluoride so liberated with materials is interrupted, and the contact maSS said alkali metal fluoride to give the correspond is replaced. The spent contact mass is then ing alkali metal acid fluoride, said period of time preferably heated to a relatively high tempera being such that the hydrocarbon effluent from said ture to decompose the alkali metal acid fluoride treatment is substantially free of organically com to yield HF which is recovered and to regen bined fluorine. erate the contact mass which is then reused, in 2. A process for treating hydrocarbon contain a repetition of the process. The temperature 30 ing organically combined fluorine to remove said to which the mass is heated in order to effect this fluorine therefrom which comprises subjecting regeneration is preferably above 650 F. This said hydrocarbon containing a minor quantity of regeneration is preferably carried out in a stream organically combined fluorine to the action of or current of an inert carrier which serves dehydrated silica-containing bauxite impregnated to carry off the hydrogen fluoride as liberated, With an alkali metal fluoride at a reaction tem the resulting mixture of carrier gas and hydro perature of from 150 to 550°F. and for a period of gen fluoride being conveyed away to a suitable time such that said bauxite catalyzes decomposi recovery point where the hydrogen fluoride is tion of the organic fluorine compounds present recovered by cooling and condensation, the car in the hydrocarbon with consequent liberation of rier gas being non-condensible. 40 the fluorine as hydrogen fluoride and combination For use in accordance with the present inven of hydrogen fluoride so liberated with said alkali tion, the alumina in the form of either bauxite metal fluoride to give the corresponding alkali. or activated alumina may be impregnated with metal acid fluoride, said period of time being an aqueous solution of the alkali hydroxide or Such that the hydrocarbon effluent from said fluoride, dried, and placed in a closed treating 45 treatment is substantially free of organically com chamber. The hydrocarbon material is then bined fluorine. . passed in either the liquid or the vapor , 3. A process for treating hydrocarbon contain preferably the former, through the contact mass ing organically combined fluorine to remove said at a space velocity of 1 to 10 volumes of liquid fluorine therefrom which comprises subjecting per volume of contact mass per hour. The tem 50 said hydrocarbon containing a minor quantity of perature maintained at the contact chamber is Organically combined fluorine to the action of preferably between about 150 and 550°F, and the dehydrated silica-containing adsorbent alumina pressure, although not critical, is preferably be impregnated with from 2 to 10 per cent by weight tween 15 and 500 p.s. i. of alkali metal fluoride at a reaction temperature Following is a specific example of the practice of of from 150 to 550 F. and for a period of time the present invention: Such that said alumina catalyzes decomposition Eacample of the organic fluorine compounds present in the hydrocarbon with consequent liberation of the A debutanizer overhead effluent from the alkyla fluorine as hydrogen fluoride and combination of tion of a C4 hydrocarbon fraction with an olefin 60 hydrogen fluoride so liberated with said alkali in the presence of HF as a catalyst is passed metal fluoride to give the corresponding alkali through a bed of calcined bauxite impregnated metal acid fluoride, said period of time being such with 6% by weight of potassium hydroxide. The that the hydrocarbon effluent from said treatment rate of flow of the hydrocarbon is 5 liquid volumes is substantially free of organically combined of hydrocarbon per volume of catalyst per volume fluorine. of contact mass per hour. The temperature is 4. A process for treating hydrocarbon contain maintained at about 180° F. The pressure is suff ing organically combined fluorine to remove said cient to maintain the hydrocarbon in the liquid fluorine therefrom which comprises subjecting phase. Substantially complete removal of the or said hydrocarbon containing a minor quantity of ganic fluorine takes place, and the effluent hydro organically combined fluorine to the action of de material is free from silicon tetrafluoride. hydrated silica-containing adsorbent alumina im When spent, the contact mass is heated in a pregnated with at a reaction stream of a butane at approximately 700 to 800° temperature of from 150 to 550 F. and for a F. to drive off HF which is recovered by cooling period of time such that said alumina catalyzes and condensation and returned to the alkylation 75 decomposition of the organic fluorine compounds 2,877,546 3 present in the hydrocarbon with consequent liber with from 2 to 10 per cent by weight of potassium ation of the fluorine as hydrogen fluoride and fluoride at a reaction temperature of from 150 to combination of hydrogen fluoride soliberated with 550 E. and for a period of time such that said said potassium fluoride to give potassium acid bauxite catalyzes decomposition of the organic fluoride, said period of time being such that the fluorine compounds present in the hydrocarbon hydrocarbon effuent from said treatment is sub with consequent liberation of the fluorine as hy stantially free of organically combined fluorine. drogen fluoride and combination of hydrogen flu 5. A process for treating hydrocarbon contain Oride so liberated with said potassium floride to ing organically combined fluorine to remove said give potassium acid fluoride, said period of time fluorine therefrom which comprises subjecting 10 being such that the hydrocarbon effluent from said hydrocarbon containing a minor quantity of Said treatment is substantially free of organically organically combined fluorine to the action of de Combined fluorine, hydrated silica-containing bauxite impregnated RhoerCK E, FRY,