United States Patent im [ii] 3,944,578 Wolf et al. [45] Mar. 16, 1976

[54] ORGANIC SUPERCONDUCTORS WITH 2,542,481 2/1951 Crandall et al 260/397.1 HIGH TRANSITION TEMPERATURES AND HIGH CRITICAL MAGNETIC FIELDS Primary Examiner—Elbert L. Roberts [75] Inventors: Alfred A. Wolf; Ernest H. Halpern, Attorney, Agent, or Firm—R. S. Sciascia; Q. E. Hodges; D. McGiehan both of Annapolis, Md. [73] Assignee: The United States of America as [57] ABSTRACT represented by the Secretary of the Organic compounds exhibit superconducting-like be- Navy, Washington, D.C. havior, as to magnetic and electrical properties, at ele- [22] Filed: Nov. 23, 1973 vated temperatures above 21°K, where 21°K is the transition temperature of most known metallic super- [21] Appl. No.: 418,337 conducting materials. The structure of the organic ma- terials according to this invention is a plurality of su- [52] U.S. CI 260/397.1; 252/108; 252/518; perconducting clusters, forming islands within a ma- 260/478 trix of insulating material. The ratio of the clusters to [51] Int. CI.2 C07J9/00 the matrix material is a minimum at 1:104. The or- [58] Field of Search 260/397.1 ganic compound comprises two distinct atomic groups termed an R group and COOM group combining as [56] References Cited R—COOM with the COOM group clustering to form UNITED STATES PATENTS superconducting islands, within the R material matrix. 2,429,899 10/1947 Sondern et al 260/397.1 15 Claims, 6 Drawing Figures U.5. fatent March 16, 1976 Sheet 1 of 3 3,^44,578 U.S. Patent March 16, 1976 Sheet 2 of 3 3,944,578 U.S. Patent March 16, 1976 Sheet 3 of 3 3,944,578

FIG. 5. 3,944, 1 2 a metal, an aliphatic organic radical, cyclic organic ORGANIC SUPERCONDUCTORS WITH HIGH radical, and aromatic organic radical and a heterocy- TRANSITION TEMPERATURES AND HIGH clic organic radical. M is a cation which may either be CRITICAL MAGNETIC FIELDS singly charged e.g. H+, Na+ etc) or multiply charged 5 and x is the valence of M. In this regard it should be BACKGROUND OF THE INVENTION noted that JC is preferably 1, M is preferably H or a Present superconductors have a transition tempera- metal cation, and most preferably an alkali metal cat- ture in the neighborhood of 21°K. While the advan- ion (particularly Na) and R is preferably a derivative of tages of the use of superconductors in some applica- cholic acid (a cyclic organic radical) or a metal such as tions are well known, there are many disadvantages in 10 Li or Cu. their use. The disadvantages include the requirement of maintaining this material at extremely low tempera- DESCRIPTION OF THE PREFERRED tures, which requires elaborate refrigeration machinery EMBODIMENT and which contributes towards inefficiency of the ap- 15 The superconducting materials of the present inven- plication of superconductors to some apparatus. For - X tion are of the formula (RCOO ) XM wherein R is example, the refrigeration power needed to compen- selected from the group consisting of a metal, a cyclic sate for the evaporation of liquid helium is between 500 organic radical, an aliphatic organic radical, an aro- to 1,000 watts for every watt of heat dissipation of the matic organic radical and a heterocyclic organic radi- liquid helium. cal; M is a cation which may be singly or multiply 20 charged and x is the valence of M. SUMMARY OF THE INVENTION Particularly good materials of the above formula are This invention relates to materials and methods of materials wherein R is a cyclic organic radical and making materials which have superconducting transi- particularly wherein R is a cholic acid derivative. tion temperatures above 21°K. The advantages of the X 25 The (COO) XM portion of the superconductors of use of such materials is that less refrigeration power is this invention are derived from the carboxyl group. needed to maintain the higher superconducting tem- Although it is preferred that M be singly charged it can perature of these materials, and therefore the effi- also be multiply charged. Among the preferred materi- ciency of use of these materials is thereby increased. als of M are hydrogen and metal cations, with H and The structure of these materials is substantially that 30 alkali metal cations being preferred, H and Na being of an insulator with superconducting-like clusters that the most preferred materials. When M is multiply form islands throughout the bulk of the material, in an 4 charged, it is preferably calcium or magnesium. approximate ratio of 1:10 . These materials can be The method of producing these cholanate supercon- considered fractional superconducters because the ducting compounds simply requires the reaction of a islands are merely superconducting clusters dispersed 35 material having at least a double covalent bond such as randomly in the bulk insulating matrix. carboxylic acid or carboxylic salt with an organic acid. As such, these materials have application in electron- In the case of the specific compounds in FIGS. 2 to 5, ics such as in very high Q circuits, in extremely wide sodium hydroxide is reacted with an acid, having the band wave guides, in electrical machinery, in magnets appropriate cholanate group to form one of the respec- hydrodynamic systems, and in fusion systems. They tive compounds shown. also can be used to make superconducting compo- 40 Another preferred series of compounds of the for- nents, such as ultra-wide band data transmission sys- mula (RCOO-) MX are those wherein R is a metal and tems, superconducting switches, superconducting en- X particularly where R is either Li or Cu. Thus the com- ergy storage devices, and for other uses in the areas of pound sodium formate having the structure radio, radar microwave elements, and navigational systems. 45 Cu-jj-O" Na+ DISCLOSURE OF THE INVENTION O A schematic construction of the organic supercon- ducting compound R-COOM according to this inven- and lithium sodium formate having the structure tion is shown as 50 Li—jj— O" Na+ O

are particularly preferred. These compounds may be formed by the following reaction sequences. The selection of the R group of atoms controls the transition temperature of the compound, whereas the Copper Sodium Formate COOM group of atoms control the intensity of super- 60 - + + conductivity or superconducting quality. Superconduc- HCOO Na + Cl2 C1COO- Na + HC1 (1) tivity is achieved when the molecules are so oriented + A + that the COOM group atoms are arranged in a cluster CuH + C1COO- Na CuCOO" Na + HC1 (2) achieving a minimum critical mass, and the R group atoms surrounding their respective COOM atoms form- Lithium Sodium Formate ing the bulk matrix, as shown in FIG. la or FIG. lb. 65 Within the meaning of this invention the supercon- + A + HCOO" Na + Cl2 ^ C1COO" Na + HC1 (1) ducting materials have the general formula (RCOO") X XM wherein R is selected from the group consisting of 3,944 ,578 A + 3 + 4 LiH + CICOO" Na LiCOO" Na + HCI (2) water. In water solution, this hydrophobic-hydrophilic combination causes the orientation of clusters as de- These compounds are prepared as follows: scribed above. It is then necessary to remove the water EXAMPLE I by dessication or evaporation to solidify the R—COOM molecule in the proper orientation to give the com- COPPER SODIUM FORMATE: 1.2 moles of sodium pound its superconductive property. Thus the addi- formate is first chlorinated by passing chlorine gas tional limitation imposed upon these superconducting through a sodium formate suspension using antimony R—COOM molecules is that one part, either the R or chloride as a catalyst. 0.1% of the sodium formate, COOM part be hydrophobic and the other respective under the application of heat, in the reaction zone io part be hydrophilic. Under this condition, the water forms chlorosodium formate which is precipitated out solution will force the COOM parts of each molecule to and filtered. This chlorosodium formate is then reacted cluster and form the superconducting islands and the R on a mole-to-mole basis with copper hydride in a glass parts to disperse and form the surrounding matrix. distillation set-up with the application of heat using a Of course when other solvents are utilized, a similar heating mantel. The resulting is 15 condition must exist in order to form the necessary vented through a glass column in the reaction vessel. grouping of the molecules. The residual copper sodium formate and copper hy- What is claimed is: dride is alcohol and water washed, thus separating the 1. A method of preparing a superconductive material copper sodium formate. The solvent is evaporated of the formula (RCOO-)j.Mx, wherein R is selected slowly under vacuum to achieve proper orientation of 20 from the group consisting of a metal, a cyclic organic the molecules. radical, an aliphatic organic radical, an aromatic or- ganic radical, and a heterocyclic organic radical; M is a EXAMPLE II cation; and x is the valence of M, comprising the steps LITHIUM SODIUM FORMATE: 1.2 moles of so- of: dium formate is first chlorinated by passing chlorine 25 preparing a water solution of the material at room gas through a sodium formate suspension using anti- temperature; mony chloride as a catalyst. 0.1% of the sodium for- establishing a vacuum over said solution; and mate, under the application of heat in the reaction zone evaporating slowly the solvent to cause the constitu- forms chlorosodium formate which is precipitated out ent molecules to orient with the COOM group in and filtered. This chlorosodium formate is then reacted 30 clusters surrounded by a matrix of the R group. on a mole-to-mole basis with in a glass 2. A superconducting material produced by the steps distillation set-up with the application of heat using a of: heating mantel. The resulting hydrogen chloride is passing chlorine gas through a sodium formate sus- vented through a glass column in the reaction vessel. pension; The residual lithium sodium formate and copper hy- 35 using antimony chloride as a catalyst; dride is alcohol and water washed, thus removing the applying heat in the reaction zone to form chlo- lithium sodium formate. The solvent is then evaporated rosodium formate; slowly under vacuum to achieve proper orientation of precipitating said chlorosodium formate; the molecules. filtering said chlorosodium formate from the other It should be noted that better results have been 40 constituents; achieved when R is a metal rather than when R is some reacting said precipitated and filtered chlorosodium type of organic radical. formate on a mole-to-mole with copper hydride The method of forming the COOM clusters and the with the application of heat; surrounding matrix of the R part of each respective distilling the resulting copper sodium formate having molecule such as the cholanates shown in FIGS. 2-5 45 the general formula R—COOM, wherein R is the and the metallic compounds shown above and de- copper and COOM is the sodium formate, and the scribed by the , is well know in the remaining copper hydride to remove hydrogen art. However, these compounds will not be supercon- chloride; ducting when originally formed. To make them super- washing with water and alcohol the residual copper conducting, it is necessary to arrange or orient the 50 sodium formate and copper hydride to dissolve and COOM parts of each compound in a cluster, and to separate out the copper sodium formate; and make the R part of each respective part, surround the evaporating slowly the solvent containing said copper cluster to thus form the matrix as shown in FIGS, la sodium formate to achieve orientation of the mole- and lb. This is accomplished by first forming the com- cules to achieve clustering of the superconducting pound, in solution or in a liquid state. In solution, the 55 COOM portion of the molecule with a surrounding COOM parts will form clusters, but they will be an matrix of the R portion. unstable structure not capable of superconductivity. It 3. The superconducting material produced by claim is thus necessary to convert the solution to a solid state 2 wherein: while retaining the orientation or arrangement of the lithium hydride replaces said copper hydride in the COOM clusters as shown in FIG. lb. This is accom- 60 reacting step to produce lithium sodium formate. plished by desiccating the compound formed in solu- 4. The method of making a superconducting material tion or evaporating the solvent in a vacuum. produced by claim 2 wherein: The orientation of COOM clusters is possible in said superconducting COOM portion is hyrophillic: water when the atomic structure of the COOM part is and said R portion is hydrophobic. hydrophilic while the atomic structure of the R part is 65 5. The superconducting material produced by claim hydrophobic. Separating and clustering of the R and 3 wherein: COOM parts is due to the affinity of the COOM part said superconducting COOM portion is hydrophillic: for water, and the self exclusion of the R part from and said R portion is hydrophobic. 5 6 6. The method of preparing the superconductive 12. The method of preparing the superconductive material of claim 1 wherein x is equal to 1. material of claim 11 wherein M is selected from the 7. The method of preparing the superconductive group consisting of hydrogen (H) and Sodium (Na). material of claim 6 wherein M is selected from the 13. The method of preparing the superconductive group consisting of hydrogen (H) and an alkali metal. 5 material of claim 1 wherein R is a cyclic organic radi- 8. The method of preparing the superconductive cal. material of claim 7 wherein M is selected from the 14. The method of preparing the superconductive group consisting of hydrogen (H) and sodium (Na). material of claim 13 wherein said cyclic organic radical 9. The method of preparing the superconductive of is a cholic acid derivitive. claim 1 wherein R is a metal. 15. The method of preparing the superconductive 10. The method of preparing the superconductive material of claim 14 wherein said cholic acid derivitive material of claim 9 wherein x is 1. is selected from the group consisting of a cholate salt, a 11. The method of preparing the superconductive desoxycholate salt, a lithocholate salt, and a cholanate material of claim 9 wherein M is selected from the ]e salt. group consisting of hydrogen (H) and an alkali metal.

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