Патент USA US2407129код для вставки
2,407,129 Patented Sept. 3, 1946 UNITED STATES PATENT OFFICE 2,407,129 PROCESS OF HALOGENATION Anthony F. Benning, Woodstown, N. J., and Joseph D. Park, Wilmington, Del., assignors to Kinetic Chemicals, Inc., Wilmington, Del., a corporation of Delaware No Drawing. Application March 14, 1944, Serial No. 526,475 3 Claims. (01. 260—653) 1 A. This invention relates to the preparation of 2 ‘ ner of its practical application, particularly in the proportions of the reactants, the tempera ture, the pressure, and the exact method of pro cedure, the following examples, in which the parts are by weight, will serve to illustrate its halogenated aliphatic hydrocarbons and, in par ticular, to halogenated derivatives of methane. B. It is, an object of the invention to prepare halogenated derivatives of methane in which the halogensare ?uorine, chlorine, or both. An other object of the invention is to prepare such compounds, many of which are disclosed in the prior art, by a process having great advantages over the prior art processes of preparing these compounds. practical application. Example I About 100 parts of activated carbon were im 1,0 pregnated with 35 parts of CI‘Fs by slurrying CI‘Fs ‘ with ether and pouring carbon into the slurry. The solvent was then removed by heating at INS-300° C. for several hours in the vacuum. The ane simultaneously with chlorine and hydrogen material thus treated was placed in an inconcl ?uoride in the vapor phase in the presence of a 15 jacketed carbon tube and heated to 275-300° C. Through this tube was .then passed a mixture of catalyst. The preferred catalyst is CI‘Fs. D. According to the commercial process of CH4, HF and chlorine, in the following ratios: C. The objects of the invention are accom plished, generally speaking, by reacting meth preparing ?uorinated derivatives of saturated aliphatic hydrocarbons, one use of which is as refrigerants,“ the compounds are made from 20 chlorinated hydrocarbons using HF as a source of ?uorine and antimony halides as catalysts or ?u Parts by weight CH4 __________________________ "V. _______ __ Chlorine _____ ___ _____ 4 60 HF _____________________________________ __ 30 orine carriers. That operation is virtually an It is advisable to ?rst start the flow of CH4, fol lowed by HF and then by chlorine. The contact exchange reaction carried out in the liquid phase with the substitution of chlorine by ?uo 25 time was about two minutes. The reaction pro ceeded very smoothly and at the end of‘ 3% rine. The hydrocarbon which is ?uorinated must, according to the teaching of the prior art hours the reaction was discontinued. An inte grating wet-test meter indicated that 15.6 parts and according to the nature of the prior art of methane had passed through the reaction process, be chlorinated before it can be ?uo 30 tube. The eiiluent gas mixtures were led through rinated. ‘ a copper ?ask (serving as a trap) into a scrub E. According to our invention, a saturated hy bing and drying system. The dried gases were drocarbon is simultaneously chlorinated and flu passed through a series of receivers cooled re orinated in a single step process which has great spectively with carbon dioxide ice in acetone and advantage, over the processes known to the prior art. This process is carried out on methane with 35 with liquid nitrogen. The pressure in the reac tion zone was maintained at about 1 atm. abs. by means of a pressure regulator at the end of the HF and chlorine together in the presence of chromium ?uoride. In the prior art process it has been theoretically stated that the so-called system. In the liquid nitrogen trap, 12 parts, of methane were collected. The carbon ice-‘acetone In this case the chromium ?uoride 40 cooled trap contained‘ 20.8 parts of material catalyst is more a ?uorine carrier than a true catalyst. has no substantial action upon methane or even upon chlorinated methane: It is, therefore, ap parently a true catalyst. This process is carried which had the following composition, obtained by Podbielniak distillation: CHCIFz _________________________ "parts-.. 0.4 out in the vapor phase. CClzFz ___________________________ __do____ 6.4: F. The chromium ?uoride catalyst may be im 45 CChF ____________________________ __do__‘__ 2 pregnated in a carbon carrier. It is prepared by C'2C13F3 __________________________ .__d0__._._ 2 methods of impregnation which will be under C014 ___________________ _._'_ _______ __do____ 8 stood by persons skilled in the art. The products C2Cls ____________________________ _..d0__.__ 2 of the reaction contain a number of compounds Organic loss ______________ __percent mole__ 6 together with unconverted reactants. The com 50 Conversion to fluorine compounds____do____ 9.6 ponents in the reaction product may be separat Yield of ?uorinated compounds ____ __do____ 42 ed in the manner herein set forth, or by any It will be observed not only that there were four other satisfactory process of separation. compounds containingboth chlorine and ?uorine G. While this invention is susceptible of con siderable variation and modi?cation in the man 55 in the product of reaction, but that the method 2,407,129 3 4 produced some carbon tetrachloride and some L. The reaction products including the un changed starting materials may be treated to isolate the ?uoro derivatives either by absorption perchlorethane. Example II of the inorganic materials in water or by con A steel-jacketed carbon tube (with the jacket 5 densation and fractional distillation of the re electrically insulated from the carbon tube) ?lled action mixture. The unchanged CH4, C12, and with activated carbon impregnated with CI'Fs HF may be recycled. (10% CrFa on carbon) was used. This tube was. electrically heated, the ends of the carbon tube , M. A particular advantage of the invention is that methane can be directly ?uorinated. An serving as electrodes. At a, tube temperature of 1O other advantage of the invention is in the direct 340° C. the ?ow of CH4, HF and C12 was started production from methane of CC12F2, a very val in the order named, at the same ratio as that uable compound. Another advantage of the in used in Example I. A contact time of about vention lies in this that methane is a much three minutes was approximated. 42 parts of cheaper starting material than the chlorinated material were collected in a carbon ice trap and 15 materials which were necessary to ?uorination by none in the liquid nitrogen trap. Substantially the processes of the prior art. A surprising fea all of this material was found to be CClzFz upon ture of the invention is that the antimony cat distillation with the Podbielniak apparatus. No alysts which are useful in the processes of the CChF was found. prior art are ineffective in this process. Another H. Super-atmospheric or sub-atmospheric 20 advantage of the invention is that in the prep pressures may be used in carrying out this inven aration of C‘ClzFz yields of the order of 35% were tion although atmospheric pressure, in general, obtained. Other catalysts which are useful in is preferred. The ratio of the various reactants the older processes of preparing such compounds may be varied within wide. limits depending upon _ have been tried and found ine?ective. Another the ?uorinated derivative of methane desired. advantage of the invention is the provision of a We have found the conditions used in Example II new process for preparing the valuable compound to be preferred for the production of CClzFz. By CHC1F2 which has heretofore been prepared only proper selection of the ratios of the various re by the ?uorination of chloroform with ?uorinat aotantsand the conditions of reaction, it is pos- I, ing catalysts such as Sb halides and mercury sible to selectively produce a. predominant quan '30 ?uorides. tity of any compound which forms a constituent N. As many apparently widely different em of the reaction product. bodiments of this invention may be made with I. The reaction temperature may also be varied out departing from the spirit and scope thereof, over a wide range although temperatures above it is to be understood that we do not limit our 550° C. are not suitable. The temperature range ' selves to the speci?c embodiments thereof except from 275° to 400° C. is to be preferred. For the manufacture of CClzFz temperatures above 300° C. are preferred. J. The reaction time necessary may also be varied depending upon the temperature of the catalyst and on the particular derivative wanted. However, in general, for the production of CC12F2 a catalyst temperature between 325°-450° C. and contact times greater than 30 seconds will fur- _ nish the most satisfactory yields. K. A suitable catalyst may be prepared from an aqueous solution of chromic chloride by im pregnation on carbon and then drying in vacuo or in a stream of nitrogen heated to above 200° C. The proportion of the catalyst to carbon . (chromium salt) may also be varied. In this in vention 5-15% of C1‘F3, based on the weight of carbon, has been satisfactorily used. The car bon may be directly impregnated with CrFa by pasting the material with ether or some other inert solvent and then drying the mixture in a current of inert gas, e. g., nitrogen, at tempera tures of 350~400° C. Other catalyst supports may . be used. as de?ned in the appended claims. We claim: 1. A process for the preparation of halogen ated saturated aliphatic hydrocarbons which comprises reacting hydrogen ?uoride and chlo rine simultaneously with methane at a tempera ture of 325° to 450° C. in the presence of chr0 mium ?uoride and separating the products by distillation. ’ 2. A process for the preparation of di?uoro dichloro-methane which comprises reacting hy drogen ?uoride and chlorine simultaneously with methane in the presence of chromium ?uoride at a temperature of about 340° C. and separating the products by distillation. 3. A process for the preparation of halogen ated derivatives of hydrocarbons which comprises reacting hydrogen ?uoride and chlorine simulta neously with methane in the presence of chro rnium ?uoride at a temperature between about 275° and 550° C. and separating the products by distillation. ANTHONY F. BENNING. JOSEPH D. PARK.