US 2631170 A
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Description (OCR text may contain errors)
March 10, 1953 R. o. FOWLER 2,631,170
PROCESS FOR THE PREPARATION OF FLUOROCARBONS Filed Feb. 15, 1945 2 2 r 2 00 F F F (EXCESS) gii lonal L n a C0 F3 i HEAT E 00 F C H G7 H 32Gb F3 3200 F2 AGITATE 1 IG l6 HF HF 0 r HF INVENTOR. Robert D. Fowler Maw Patented Mar. 10, 1953 i itocsss ma irHE PREPARATION or FLUOROCARBONS Robert Dudley Fowler, Baltimore, Ma; assignor to the United States of America as represented by the United States Atomic Energy Commission Application February 13, 1943', Serial No; 475,852
. 3 Claims.
This invention relates to the preparation of fiuorocarbons and more particularly to a method of preparing fiuorocarbons by the reaction between hydrocarbons and metal fluorides.
One object of this invention resides in the provision of an improved process of producing fiuorocarbons in a relatively simple, economical and commercially feasible manner.
A further object resides in the provision of such a method characterized by the fact that fiuorination of hydrocarbon compounds will take place in the absence of a catalytic agent.
A still further object resides in the production of new and hitherto unknown fiuorocarbons.
Other objects will in part be obvious and in part be pointed out hereinafter. s
. In general, the invention contemplates the passage of a hydrocarbon vapor over, through, 01 in intimate association with a metal fiuorideof higher than normal fluorine constituency; as for example, cobalt trifiuoride (Jo-F3; silver difiuoride AgFz, or manganese trifiuoride MnFs.
The term hydrocarbon as used hereinafter shall be construed to include all hydrocarbons, i. e., olefinic, paraffinic, aroma-tic, naphthenic, etc.
Any desired hydrocarbon in vaporized form may be used, for example, heptane C'1H1s, hexane CsHm, cyclohexane Cal-I12, toluene CvHa, xylene CaH1o, mesitylene C9H12, octane, or any iso-octane CsHis.
Any suitable apparatus may be utilized for the carrying out of the process of this invention, a specific example of which will now be described in conjunction with the accompanying drawing wherein:
The single figure comprises a schematic flow sheet.
The specific embodiment now described contemplates the use of cobalt trifluoride, a product not at present commercially available :but which may be prepared as follows:
Cobalt chloride hexahydrate CC12-6H2O is dehydrated in any suitable manner to the anhydrous form (C0012) and subjected to the action of anhydrous hydrogen fluoride, HF, forming the known cobalt difiuoride COFz according to the reaction:
cobalt difiuoride may be converted to the trifiuoride by direct fiuorination, at any suitable elevated temperature above approximately 150 C. according to the reaction:
the anhydrous Com is now placed in a suitable receptacle. 7 V
Such a receptacle may take the form of a syum der having a series of electrical or other heating elements positioned thereabout. It has been discovered that it the temperature of such a recep'ta'cle is graduated progressively from the in let end to the outletthrough a range of approx: imately C. to 400 'C. a relatively higher yield of the desired fluorocarbon as will be discussed hereinafter, will result. t has also been found that the provision of suitable means for slowly rotating the cylinder axially win obviate channeling 'of the core upon the introduction of the organic compound. 7 I The cylinder may be partially or substantially entirely filled with Col and heated to the grade:- ated temperatures above. mentioned. it hydro carbon, CiHic is now passe into the chamber and reacts according to the following equation C'IHis-I32COF3 C7Fl6+ 16HF+ 32COFz A small culinary or an inert sweeping as such as nitrogen maybe introduced with the hydro carbon for the purpose or clearing the reaction chamber if desired.
Upon the completion of the reaction above mentioned C7F1e and HF may be drawn from the reaction chamber together and subsequently separated in any desired manner as by fractional distillation, or condensing in a coo-ling chamber, following separation of the two liquid phases. Yields of fluorocarbons by the above method have exceeded seventy percent in quantity of the initial hydrocarbon input.
Having reference now to the accompanying flow sheet the process will be readily understood. The left hand vertical column indicates the ingredients, chemical and physical (i. e. agitation) embodied in the process. The center vertical column designated the reactions and the third vertical column the incidental resultants.
It should here be pointed out that the COFz initially used suffers virtually no quantitative loss in the process and may be reutilized as frequently as feasible.
Additionally, if desired the fiuorination of the lower metal fluoride and exposure of the higher fluoride to the hydrocarbon may be carried out in the same chamber in order to avoid shifting the fluoride, if a step by step process rather than the continuous chain process above described, is desired. In such case however, care must be taken thoroughly to cleanse the reaction vessel with an inert gas between operations.
From the above it will be apparent that virtually any desired fluorocarbon may be produced by proper solution of ingredients to give a high yield of a resultant fluorocarbon. For example, exposure of COFa to an octane C8H18 or dodecahydrobiphenyl C12H22, will react according to the following equations:
As previously pointed out it will be understood that the use of other higher metal fluorides and other hydrocarbons will produce other fluorocarbons as may be desired.
Now from the foregoing, it will be seen that there is herein described a simple, economical and commercially practicable method for the production of fluorocarbons.
As many embodiments may be made of this inventive concept and as modifications may be made in the embodiments herein shown and described, it is to be understood that allmatter hereinbefore is to be interpreted merely as illus trative and not in a limiting sense.
1. In the preparation of perfiuororganic compounds, the step of reacting a trifluoride selected from the group consisting of manganese trifiuoride and cobalt trifiuoride with a hydrocarbon vapor at a temperature between 150 C. and 400 C. until all of the hydrogen of said hydrocarbon has been replaced by fluorine.
2. In the preparation of perfluoro organic compounds, the step of reacting manganese trifiuoride with a hydrocarbon vapor at a temperature between 150 C. and 400 C. until all the hydrogen of said hydrocarbon has been replaced by fluorine.
3. In the preparation of perfiuoro organic compounds, the step of reacting cobalt trifiuoride with a hydrocarbon vapor at a temperature between 150 C. and 400 C. until all the hydrogen of said hydrocarbon has been replaced by fluroine.
ROBERT DUDLEY FOWLER.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number 7 Name Date 1,978,840 Henne Oct. 30, 1934 2,004,931 Daudt et al June 18, 1935 2,013,030 Calcott et al Sept. 3, 1935 2,090,772 Wiezevich Aug. 24, 1937 2,129,289 8011 Sept. 6, 1938 2,186,916 Wiezevich Jan. 9, 1940 2,307,773 Egloff Jan. 12, 1943 FOREIGN PATENTS Number Country Date 214,293 Great Britain Apr. 14, 1924 730,874 France Aug. 25, 1932 OTHER REFERENCES Mellor, Comprehensive Treatise on Inorganic and Theoretical Chemistry, vol. 14, pages 608-9.
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