Aug. 17, 1948. C. M. FONTANA 2,447,323 OXYGEN ABSORBENT MEDA IWWEWTOR 4770'RAVEY Aug. 17, 1948. C. M. FONANA 2,447,323 OXGEN ABSORBENT MEDIA Filed Aug. 7, 1944 3. Sheets-Sheet 3 ??? 3. ? 20 20 % of CoAA2 SAZT 4.S. CUPRIC CALOALDE A /ELT 77Z/ 32 MOZ. 272 ACZ AF TVG. 3 Celeste 4. Föntaga AY ???ht??????????? 47 ????????? Patented Aug. 17, 1948 2,447,323 UNITED STATES PATENT OFFICE ?2.44?.32? OxG3NASSORSENT SEA Celeste ME, Fontging, Dallas, Tex, assignor, by mesme assignments, to socony-Vacuum 0i: Company, incorporated, New York, N.YY., a cor poration of New York Appleation August 8, 1944, Seria No. 543,349 Claim. (C. 2 This invention relates to a method of extract The most widely used method for producing ing oxygen from the air by the use of molten salts chlorine is the electrolytic method. Other methr comprising the chlorides of copper in admixture ods involve.the recovery of chlorine from hydro . with alkali metal halides, especially alkali metal gen chloride. The prior art &mployed in general, chlorides such as postassium chloride. More par two methods for converting hydrogen chloride ticularly the invention is concerned with the preparation of melt mixtures of copper chlorides catalyticto chlorine. oxidation The offirst hydrogen method chloride involves to directchlo and potassium chloride in concentrations so ad rine. Common among the catalysts employed justed that the melting points of such mixtures have been copper halides supported on porous are sufficiently low that oxygen may be absorbed 10 materials such as pumice. Promoted copper Catar from the air by the liquid melts as hereinafter lysts having some other substance added to in described and as described in greater detail in prove their catalytic activity have also been pro U. S. Patent 2,418,402. The invention is also con posed. Addition agents suggested as effective are cerned with the preparation of such melts for oxygen compounds of vanadium, beryllium, mag utilization in the process of making chlorine and 15 nesium, bismuth, antimony, uraniuxin and rare chlorinated hydrocarbons as described and earth metal compounds. These catalytic proc claimed in U. S. Patents 2,407,828, 2,418,930 and esses all suffer from the same disadvantage, viz., 2,418,93. the products from the catalytic converters re The present invention concerns the optimum quire difficult and expensive treatment in order concentrations of the chlorides of copper and of 20 that quantitative yields of pure chlorine be ob potassium chloride in said melts to obtain high, tained. rates of oxygen absorption from the air, and also The second method proposed in the prior art to produce melts which are liquid at tempera for the production of chlorine is a cyclic tWor tures of operation of the various steps of the stage process, involving in the first stage, abr processes, thereby making possible continuous 25 sorption of the hydrogen chloride in a metal cyclic operation. oxide, whereby the metal oxide is converted to Numerous methods have been proposed in the the chloride, and, in the second stage, the recon prior art for the preparation of oxygen from air. version of the metal chloride to the oxide and chlo These methods may be classified as those involv rine by means of oxygen at a higher temperature. ing physical methods of separation such as lique 30 The “Mond” process is a typical example of such faction followed by fractionation of the liquid air a process in producing only a dilut? chlorine con and those involving chemical methods such as taining gas and having the additional disadvan absorption and desorption of oxygen by chemical tage of the necessity of alternately cooling and oxidation and reduction of solids such as oxides heating a stationary mass in the converter over a of polyvalent metals, the higher oxides of which 3 5 considerable temperature range while changing are reducible by heating at moderately high Over from One stage of the operation to the other, temperatures. One of the earliest commercial resulting in heat losses and inefficient use of the methods of the latter class involved the absorp Converter during the heating and cooling opera tion of oxygen by the lower oxides of barium or tions. As in the case of a more efficient method manganese to form the higher oxides of these 40 for producing oxygen, the present invention sup metals which were then desorbed of oxygen either plies a medium for oxygen absorption and heat at elevated temperature or reduced pressure. transfer thus making possible a continuous cyclic These methods proved cumbersome in practice process for producing chlorine. and in the case of barium oxide (Brin's process) A third process to which my invention is an im required relatively pure air with respect to car 45 portant contribution is that of recovering hydro bon dioxide content. Hence liquefaction methods gen chloride in the form of alkyl halides such as were later adopted. However, liquefaction meth methyl chloride described in detail in the here ods are intrinsically expensive involving costly inabovementioned U. S. Patent 2,407,828. Hydro high pressure refrigeration equipment. The pres gen halides, such as hydrogen chloride, are lib ent invention relates to a chemical method adapt 50 erated in the production of alkyl halide inter able for continuous production of oxygen from mediates by halogenation of hydrocarbons and in ordinary air by employing melts of copper chlo the conversion of such halides to the final prod rides with alkali metal chlorides in such propor lucts; hence the commercial feasibility of these tions as to give liquid media for maximum rate processes usually depends upon the economical of oxygen absorption. 55 recovery of the halogen acids and their recon 244,828 3 version to the corresponding halide. Prior art 4 m methods have attempted the recovery and recon as methyl chloride, this may be accomplished in version of halogen acids by processes wherein the à sepàtrate Žone by contacting the neutralized oxidation of the acid and the chlorination of oxychloridepressed by the molten equation: mass with methane as ex methane are carried out simultaneously. For ex ample, it has been suggested that methyl chloride be produced by passing a mixture of methane, hydrogen chloride and air, or oxygen, over a sup As described in detail hereinbelow, I have illus ported copperhalide catalyst. In the use of meth trated my process diagrammatically in Figure ods involving simultaneous oxidation of hydro O wherein is shown the application of the copper chloric acid and chlorination of hydrocarbons, chloride-potassium chloride melts in a process for particularly methane, the yields of chloroneth. converting hydrogen chloride to alkyl chlorides mes are low and considerable hydrogen chloride using copper chloride-potassium chloride melts passes through the converter unchanged and the in Optimum concentration of potassium chloride, chloromethanes are highly diluted with Water cuprous chloride and capric chloride. The process vapor and air, thus requiring additional and ex 5 incorporates three successive steps wherein the pensive processing to obtain the chloromethanes principal reactions occurring in the steps are ill in purified förii?i. lustrated by Equation 1, Equation 3 and Equation 5 respectively. The first reaction zone is desig A primary object of the present invention is to nated as the preoxidation zone, the next zone is provide melts of copper chloride with alkali metal 20 designated the oxidation-neutralization zone and halides, preferably with potassium chloride, for the final Zone, the chlorination zone, utilization as absorbent media for oxygen in im Since it is desirable to maintain the melt in a proved continuous cyclic processes for the produc liquid state in the operation of a continuous cyclic tion of oxygen, and for the production of chlorine process, the choice of composition of the melt to or chlorinated hydrocarbons from hydrogen chlo 925 be used is determined (i) by the freezing point ride involving an oxidation step. of the melt as affected by change of composition A further object of the invention is to provide relative to proportions of cuprous chloride and melts of the chlorides of copper with potassium cupric chloride in successive steps of the process chloride in such proportions that maximum rates and by the mole percent of potassium chloride in of absorption of oxygen from the air can be ob 30 the melt, (2) by the desired rate of oxidation of taimed at operating temperatures adaptable to the melt, and (3) by the desired rate of chlorina improved methods of producing oxygen, chlorine tion by the melt. or chlorinated hydrocarbons. It has been found that potassium chloride as a An additional object of this invention is to third component in admixture with cupric and produce a carrier supported mixture of chlorides 35 cuprous chlorides produces melts of relatively low of copper and potassium chloride in such pro freezing points and other suitable properties, and portions of potassium chloride to copper chlorides hence is a desirable component in such a mixture that the heated mixture of chlorides will show for reducing to continuous cyclic operation proc high rates of oxygen absorption. esses involving the use of these components such Still another object of the invention is to pro 40 as for the production of oxygen, for the oxidation duce oxygen absorption melts of copper chlorides of organic materials, for the production of chlo with potassium chloride in proportions such that rine and for the chlorination of hydrocarbons. said melts may be readily maintained in the liq I have found that in addition to producing rela uld phase in all of the steps and transfer opera tively low freezing pointmelts of copper chlorides, tions in the methods referred to above for pro 45 potassium chloride at optimum concentrations ducing oxygen, chlorine, or chlorinated hydrocar greatly increases the rate of Oxidation of cuprous bonS.