3,®75,8%Z7 United states Q@ Patented Jan. 29, 1963 1 2 atmosphere or by ?lling these spaces with inert gases‘. 3,075,827 7 The reaction vessel 2 preferably includes suitable heating PRGCESS FGR PR?DUCl-NG ANHYDRGUS means 4 and agitating means 6 for respectively heating LETHIUM PERCBEQRATE John W. Cretzrneyer, Minneapolis, Minn., assignor to and agitating the contents of the vessel. If the tempera Lithium Corporation of America, Inc, Minneapolis, ture to which the starting materials are heated to dissolve Minn, a corporation of Minnesota the salts and to effect the et?cient reaction thereof is Filed Sept. 8, 1959, Ser. No. 838,695 above the boiling point of the organic solvent, then an 8 Claims. (Cl. 23-85) excess of solvent is used and the evaporated solvent is fed to a condenser where it is condensed and returned This invention relates to a process and apparatus for 10 to the reaction vessel. To this end, an outlet conduit 8 producing anhydrous lithium perchlorate. The pro extends from the top of the reaction vessel 2 to a suit duction of anhydrous lithium perchlorate by processes able condenser ltl which condenses the evaporated or heretofore known involves the production of lithium per ganic solvent and returns the condensed solvent through chlorate containing water of hydration followed by a de a return conduit 12 to the reaction vessel. hydration procedure at elevated temperatures. The de 15 As previously indicated, the chemical reaction be— hydration procedure is slow and, therefore, costly. It is, tween the dissolved anhydrous starting materials pro~ accordingly, an object of the present invention to provide duces the desired lithium perchlorate dissolved in the a process and apparatus for producing anhydrous lithium organic solvent and a precipitate of the other reaction perchlorate which avoids the disadvantages of these proc product which would be sodium chloride if sodium per esses, particularly the costly dehydration of hydrated 20 chlorate and lithium chloride were the starting materials. lithium perchlorate at elevated temperatures. A discharge conduit 13 having an initially closed valve The process in its broader aspects involves reacting to 14 extends from the bottom portion of the reaction ves gether an anhydrous salt of perchloric acid other than sel 2 to a suitable ?lter 18. When the reaction between lithium perchlorate with an anhydrous lithium salt which the starting materials in the reaction vessel 2 is complete, reacts by double decomposition with said anhydrous salt 25 the valve 14 is opened to allow the contents of the re of perchloric acid, said reaction being carried out in an action vessel to pass through ?lter 18, which removes the organic non-aqueous solvent in which lithium per insoluble reaction product. The ?ltrate passes through a chlorate, said anhydrous salt of perchloric acid and said conduit 19 into a distillation kettle 22, and the ?ltered anhydrous lithium salt are soluble, but in which the salt precipitate is recovered from the ?lter. The distillation other than lithium perchlorate resulting from the reaction 30 kettle 2?. includes suitable agitating means 24 for agitat is insoluble. The thus produced anhydrous lithium per ing contents thereof and heating means 26 which effects chlorate is readily recovered from the organic solvent, the distillation of the organic solvent. The distillation for instance, by ?ltering out the insoluble salt and dis of the organic solvent may be aided, if desired, by ap tilling off the solvent from the ?ltrate. plication of vacuum to the kettle. The distilled solvent ‘ The process works most eifectively when the starting 35 passes through a conduit 28 ‘at the top of the distillation materials are anhydrous sodium perchlorate and anhy kettle to a suitable condenser 30 where the solvent is con drous lithium chloride, dissolved in a low' molecular densed and passed through a conduit 32 to a suitable re weight alcohol, such as methanol, ethanol, propanol or ceiver or storage tank 36. Anhydrous lithium per butanol, preferably a propyl alcohol such as n-propanol ihlorate crystals form in the bottom of the distillation or isopropyl alcohol. Although less preferred, instead of ettle. sodium perchlorate, ammonium, magnesium, strontium When the organic solvent is substantially completely or barium perchlorate can be used; and, instead of lithium evaporated, the heat (and vacuum is used) are cut off and chloride, lithium bromide, lithium nitrate, lithium nitrite an on-otf valve 38 in a conduit 40 extending between or lithium ehromate can be used. Although low mo ,a toluene supply tank 42 and the distillation kettle is lecular weight alcohols are decidedly the preferred sol~ 45 opened to feed toluene to the distillation kettle. Sulli vents, other organic solvents satisfying the foregoing re cient toluene is added to just cover the lithium per quirements can be utilized, particularly acetone which pro~ chlorate crystals in the distillation kettle. Next, the dis duces very satisfactory results when barium or strontium tillation kettle is sealed by closure of the various valves perchlorate is used as a starting material. in the conduits leading thereto, and heat and vacuum are Another aspect of the present invention resides in the applied to distill the toluene. As the toluene distills, it apparatus for carrying out the basic process of the inven carr1es with it as an azeotrope any solvent or moisture tion briefly described above. Examples of this apparatus which may still be in the distillation kettle. The distilled are described in the speci?cation to follow and illustrated toluene passes through the conduit 28 into the condenser in the drawings wherein: 30, and the condensed toluene may then be carried to a FIG. 1 is a diagrammatic illustration of apparatus suit 55 suitable location through a discharge conduit 44 having able for carrying out the process of the present inven an on-otf control valve 46. After‘the toluene has been tion; and completely distilled, the contents of the distillation FIG. 2 is a diagrammatic illustration of other appa; kettle are preferably heated and agitated for several hours ratus for carrying out the process of the present inven or more to free the lithium perchlorate of any volatile tion. 60 materials. Referring to FIG. 1, the starting ingredients are initially Reference is now made to FIG. 2 which shows a pre charged into a reaction vessel 2. As above indicated, the ferred form of apparatus for producing lithium perchlo starting ingredients are (a) an anhydrous salt of per rate. That part of the system illustrated following the chloric acid other than lithium perchlorate, most desir reaction vessel 2, is identical with the corresponding por ably sodium perchlorate, (b) an anhydrous lithium salt, tion of the system shown in FIG. 1, and thus will not again such as lithium chloride, and (c) a substantially non be described, and all common elements used in the two aqueous or anhydrous organic solvent, preferably a low systems are similarly numbered. molecular weight alcohol, in which the above mentioned The apparatus illustrated in FIG. 2 di?’ers from that salts are dissolved. The spaces within reaction vessel 2 shown in FIG. 1 in the addition of an extractor 50 be— and the other conduits and vessels to be described are kept 70 tween the condenser 1d and the reaction vessel 2. In essentially free of moisture in any suitable way, such as the preferred process, only the lithium salt starting ma v by mechanically sealing the spaces from the surrounding terial, such as lithium chloride, and the organic solvent 3,076,827 4 are initially placed in the reaction, vessel 2. The per to 180° C. and maintained there, for example, for from chlorate salt starting material, such as sodium perchlo 2 to 4 hours while the contents of the kettle are continu rate, is placed in its crystalline form in the extractor 50. ously agitated. White crystals of anhydrous lithium per The extractor has a discharge opening 51 in the bottom chlorate form and these are removed from the distillation thereof which communicates with the top of the reaction kettle. vessel and this opening is covered by a porous disk 52 It is important that the anhydrous perchlorate used as made, for example, of sintered glass which prevents the one of the starting materials in the practice of the present passage of the perchlorate salt crystals to the extractor 5G. i invention be essentially free of chlorates. Thus, for in The perchlorate salt crystals in the extractor 50 stance, the readily available commercial solutions of sodi are thus gradually dissolved in the liquid organic solvent 10 um perchlorate, from which anhydrous sodium perchlo being returned from the condenser 10F to the reaction rate is obtained, contain about 0.5 to 0.67%, by weight, vessel 2. This process of feeding perchlorate salt to the of sodium chlorate. Unless this sodium chlorate is re reaction vessel is of particular utility where the perchlo moved, for instance, prior to the drying of the sodium per rate salt has only a limited solubility in the organic solvent chlorate solution, safety hazards would arise in the prac involved. For example, sodium perchlorate has only 15 tice of the process of the present invention because of limited solubility in organic solvents such as propanol, the unstable nature of sodium chlorate. It has been so that a rather large volume of solvent would otherwise found that the following procedure is very satisfactory be required in order to carry out the practice of the pres for reducing the chlorate content. Thus, hydrochloric ent invention of the perchloratecrystals were to be initial acid (or other acids or reducing agents), when added to ly placed in the reaction vessel as in the embodiment of 20 sodium perchlorate solutions containing sodium chlo the invention illustrated in FIG. 1. rate, serves to reduce chlorate to chloride and thence to ‘ The following examples are illustrative of the practice chlorine, without affecting the perchlorate. In a typical of the process of the present invention: practice of using this technique, hydrochloric acid is added to a sodium perchlorate solution in a ratio of about 5 Example 1 mols per mol of chlorate. The reaction is started by gentle warming after which it becomes somewhat exo _ 10 grams of anhydrous lithium chloride and 28.8 grams thermic and proceeds at about 80 degrees C. to comple of anhydrous sodium perchlorate were dissolved separate tion. The chlorine which is- formed in the reaction is ly in dry methanol. The twov solutions were then mixed boiled ed with the water of solution and the sodium per together whereupon sodium ‘chloride precipitated out. 30 chlorate monohydrate thus recovered can be safely dried The said precipitate was ?ltered off and the ?ltrate evapo at about 150 degrees C. or higher to form the anhydrous rated to dryness. The anhydrous lithium perchlorate sodium perchlorate. Any small amount of sodium chlo product recovered from the evaporation was dissolved in ride in the original solution of sodium perchlorate, or dry isopropanol and ?ltered to remove the last traces of formed in the reaction, will not interfere with the use of sodium chloride. The ?ltrate wasv again evaporated to said anhydrous sodium perchlorate because of the insolu dryness yielding 24.2 grams of anhydrous lithium per~ bility of sodium chloride in the organic solvent selected, chlorate (theor. 251 grams). A total of 13.9 grams of for instance, n-propanol. sodium chloride (theor. 13.8 grams) was precipitated. 'As further examples of the practice of the process of Example 2 the invention, the following can be used as starting ma 40 terials in an alcohol solvent, such as isopropyl alcohol, The following is a speci?c example, by way of illustra for making ‘anhydrous lithium perchlorate: tion, of one set of process ‘conditions which can be used (1) Sodium perchlorate and lithium nitrate or lithium for making anhydrous lithium perchlorate with the ap nitrite; paratus shown in FIG.‘ 2, using anhydrous lithium chlo~ (2) Magnesium perchlorate and lithium nitrate; and ride and anhydrous sodium perchlorate as starting mate 45 ‘(3) Barium perchlorate and lithium chloride, lithium ni rials. One part of anhydrous lithium chloride and 7 to trite, lithium nitrate or lithium chromate. 8 parts, by weight, of a low molecular weight alcohol, substantially free of water, preferably isopropyl alcohol, Additional examples of the practice of the process of are introduced into the reaction vessel 2. Anhydrous the invention include, as starting materials, ammonium sodium perchlorate .(free of ‘any chlorate) ‘in an amount 50 perchlorate and lithium chloride in ethyl'alcohol; barium equimolar with the lithium chloride is placed in the extrac perchlorate and lithium bromide in acetone; and strontium tor 50. When the lithium chloride is dissolved, which perchlorate and lithium bromide or lithium nitrate in maybe "aided by heat and agitation, the contents of the acetone. However, as previously stated, sodium perchlo reaction vessel 2 are heated to boiling. The alcohol rate and lithium chloride are the distinctly preferred start ‘vapors are condensed in condenser 10 and returned 55 ing materials and their use represents a particularly im through the extractor 50 to dissolve the anhydrous sodium portant, though limited, embodiment of the invention. perchlorate therein. When the sodium perchlorate'in the The process of the present invention operates with ‘extractor 50 is completely dissolved bypthe ‘condensed al nearly 100% yield and is substantially less expensive than cohol passing therethrough, and the reaction in reaction the "dehydration methods of obtaining anhydrous lithium vessel ‘2 is completed, the heating and agitation of the 60 perchlorate heretofore used. contents of the reaction vessel are stopped. The reac 'It should be understood that’ numerous variations may tion mixture is then allowed to cool to room temperature, be made in the speci?c apparatuses disclosed, the in after which it is passed throughrthe ?lter 18 and into the gredients and the proportions thereof and the operating distillation kettle '22. The mixture in the distillation conditions‘ described above without deviating from the kettle is agitated and heated under vacuum conditions to 65 broader aspects of the present invention. ‘distill off the alcohol without permitting the temperature What I claim as new and desire to protect [by Letters to rise above 120 degrees‘C. When the alcohol ceases to Patent of the United States is: ' condense, the heat and vacuum are cut and then toluene 1. In a process for the production of substantially an ' is added to just cover the crystals and the contents of the hydrous lithium perchlorate, the steps which comprise distillation kettle are againv agitated and heated under 70 reacting an anhydrous salt ‘(71) of perchloric acid other vacuo, maintaining the temperature below 120 degrees C. than ‘said lithium perchlorate with an anhydrous lithium As'the toluene distils, it carries with it as an azeotrope vsalt (2) in an anhydrous organic solvent in which lithium “any alcohol and/or moisture which may‘ remain in the perchlorate, ‘said salt {1-) of perchloric acid and said an— product.’ When toluene ceases, to distill, the temperature hydrous'lithidm salt (2) are soluble but in which the salt l'ofithe contents 'of the distillation kettleeis gradually raised 75 .(3) other than lithium perchlorate resulting from the 8,075,827 5 6 reaction is insoluble, whereby to produce lithium per the lithium perchlorate, and condensing the evaporated chlorate in solution in said organic solvent and to precipi solvent and returning the condensed solvent to the reac tate out said salt (3), and recovering said lithium per tion zone. chlorate from said solution. 7. In a process for the production of substantially 2. In a process for the production of substantially anhydrous lithium perchlorate, the steps which comprise anhydrous lithium perchlorate, the steps which comprise dissolving in a ?rst vessel an anhydrous lithium salt (1) reacting anhydrous sodium perchlorate with an anhydrous in an anhydrous organic solvent in which lithium per lithium salt (a) selected from the group consisting of chlorate and an anhydrous salt (2) of perchloric acid chloride, bromide, nitrate, nitrite and chromate, in a other than said lithium perchlorate are also soluble, but solution of an anhydrous low molecular weight alcohol in which the salt (3) comprising the cation portion of in which lithium perchlorate, sodium perchlorate and said salt (2) of perchloric acid and the anion portion said lithium salts (a) are soluble but in which the of said lithium salt (1) is insoluble, circulating part of sodium salt resulting from the reaction is insoluble, the solvent in said ?rst vessel through a second vessel whereby to produce lithium perchlorate in solution in containing said salt of perchloric acid in its anhydrous said alcohol and to precipitate out said sodium salt, and form to dissolve the latter salt which is carried in solu recovering said lithium perchlorate from said solution. tion to said ?rst vessel, ?ltering out the insoluble salt 3. In a process for the production of substantially (3) resulting from the reaction of said lithium salt (1) anhydrous lithium perchlorate, the steps which comprise and said salt (2) of perchloric acid in said ?rst vessel, reacting an anhydrous perchlorate (a) selected from the and recovering lithium perchlorate from said solvent. group consisting of sodium, ammonium, magnesium, 20 8. In a process for the production of substantially an strontium and barium, with an anhydrous lithium salt hydrous lithium perchlorate, the steps which comprise (b) in a solution of an anhydrous low molecular weight dissolving in a ?rst vessel anhydrous lithium chloride in alcohol in which lithium perchlorate, salt (a) and said an anhydrous low molecular weight alcohol in which lithium salt (17) are soluble but in which the salt (c) lithium perchlorate and sodium perchlorate are also solu other than lithium perchlorate resulting from the reac~ 25 ble but in which sodium chloride is insoluble, circulating tion is insoluble, whereby to produce lithium perchlorate part of the alcohol in said ?rst vessel through a second in solution in said alcohol and to precipitate out said salt vessel containing anhydrous sodium perchlorate by heat (c), and recovering said lithium perchlorate from said ing the contents of said ?rst vessel to a temperature in solution. excess of the boiling point of the alcohol, condensing the 4. In a process for the production of substantially 30 evaporated alcohol and passing the condensed alcohol anhydrous lithium perchlorate, the steps which comprise into said second vessel to dissolve said sodium perchlo reacting anhydrous sodium perchlorate with anhydrous rate which is then carried in solution to said ?rst vessel, lithium chloride in an anhydrous propyl alcohol whereby ?ltering out the insoluble sodium chloride resulting from to produce lithium perchlorate in solution in said alcohol the reaction of the lithium chloride and the sodium per and to precipitate out sodium chloride resulting from the 35 chlorate in said ?rst vessel, and recovering lithium per reaction, and recovering said lithium perchlorate from chlorate from the alcohol. said solution. 5. In a process for the production of substantially References Cited in the ?le of this patent anhydrous lithium perchlorate, the steps which comprise UNITED STATES PATENTS reacting anhydrous sodium perchlorate with an anhydrous 40 lithium halide in a solution of an anhydrous low molec 1,191,916 Brooks et a1 ______.. July 18, 1916 ular weight alcohol in which lithium perchlorate, sodium 1,273,208 Weil ______July 23, 1918 perchlorate and said lithium halide are soluble but in 1,303,167 Collett ______May 6, 1919 which the corresponding sodium halide is insoluble, 1,824,101 Smith ______Sept. 22, 1931 whereby to produce lithium perchlorate in solution in 45 2,091,898 Weber ______Aug. 31, 1937 said alcohol and to precipitate out said sodium halide, 2,373,646 Binnington ______.... Apr. 17, 1945 and recovering said lithium perchlorate from said solu 2,374,870 Litton ______May 1, 1945 tion. 2,816,814 Plucknett ______Dec. 17, 1957 6. In a process for the production of substantially 2,929,680 Stern ______.._. Mar. 22, 1960 anhydrous lithium perchlorate, the steps which comprise OTHER REFERENCES reacting an anhydrous salt (1) of perchloric acid other Mellor: Comprehensive Treatise on Inorganic and than said lithium perchlorate with an anhydrous lithium Theoretical Chemistry, vol. 2, pages 395~398 (1922), salt (2) in an anhydrous organic solvent in which lithium Longmans, Green & Co., New York. perchlorate, said salt (1) of perchloric acid and said Fischer Scientific Co., Catalog, “Modern Laboratory anhydrous lithium salt (2) are soluble but in which the 55 Appliances for Chemical Biological, Metallurgical Labora salt (3) other than lithium perchlorate resulting from tories,” pages 496-497 (1934), Pittsburgh, Pa. the reaction is insoluble, whereby to produce lithium per Mellor: Comprehensive Treatise on Inorganic and chlorate in solution in said organic solvent and to precipi Theoretical Chemistry, supplement II, part 1, pages 606 tate out said salt (3), and, during the reaction, re?uxing said organic solvent by successively heating the solvent 60 609 (1956), Longmans, Green & Co., New York. in the reaction zone to evaporate the solvent, recovering