Patents by Inventor V. N. Mallikarjuna Rao

V. N. Mallikarjuna Rao has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5395999
    Abstract: A chlorofluorination process is disclosed which employs a catalyst comprising chromium oxide for producing halohydrocarbons of the formula CHXFCF.sub.3 (where X is selected from Cl and F). The process is characterized by feeding a combination of components comprising (i) at least one halohydrocarbon starting compound selected from CHCl.dbd.CCl.sub.2 and CH.sub.2 ClCF.sub.3, (ii) hydrogen fluoride and (iii) chlorine, to a reaction zone; contacting said combination of compounds in said reaction zone with a catalyst comprising chromium oxide at an elevated temperature to produce reaction zone products containing halohydrocarbons of the formula CHXFCF.sub.3 together with halohydrocarbon reaction products of the formula CHYClCF.sub.3 (wherein Y is selected from Cl and H); and recovering at least a portion of the reaction zone products from the reaction zone including at least one halohydrocarbon of the formula CHXFCF.sub.3.
    Type: Grant
    Filed: October 20, 1993
    Date of Patent: March 7, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Mario J. Nappa, V. N. Mallikarjuna Rao
  • Patent number: 5382704
    Abstract: A process is disclosed for producing a fluorinated ether of the formula R.sub.2 CHOCF.sub.2 A, where A is Cl or F, and each R is H, (CF.sub.2).sub.n Cl, (CF.sub.2).sub.n F or (CF.sub.2).sub.n H (n is an integer from 1 to 10) by reacting a first reactant of the formula R.sub.2 CHOY where Y is H, COF, COCl or COOCHR.sub.2 (R is as defined above), a second reactant selected of the formula CZ.sub.2 Cl.sub.2 or COZ.sub.2 where each Z is independently Cl or F (provided that when A is Cl, the second reactant is CZ.sub.2 Cl.sub.2), and HF; and recovering the fluorinated ether from the reaction products. Also disclosed are bis-ethers of the formula (CF.sub.3 (CF.sub.2).sub.m).sub.2 CHOCF.sub.2 OCH(CF.sub.2).sub.m CF.sub.3).sub.2, where m is an integer of 0 to 3, which can also be produced by the process.
    Type: Grant
    Filed: June 30, 1993
    Date of Patent: January 17, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Carl G. Krespan, V. N. Mallikarjuna Rao
  • Patent number: 5345017
    Abstract: The fluorine content of an acyclic saturated compound of the formula C.sub.n F.sub.a X.sub.b having at least one carbon with at least two fluorine substituents (wherein each X is independently selected from Cl and Br, and wherein n is 1 to 4, a is 2 to 10, b is 0 to 8, and a+b equals 2n+2) is reduced by reacting the acyclic saturated compound with HCl in the vapor phase at an elevated temperature in the presence of a catalyst, the mole ratio of HCl to the acyclic saturated compound being at least about 2:1.
    Type: Grant
    Filed: November 5, 1993
    Date of Patent: September 6, 1994
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: V. N. Mallikarjuna Rao, Steven H. Swearingen
  • Patent number: 5321170
    Abstract: A process is disclosed for producing HFC-134a which includes reacting certain tetrahaloethane starting materials (e.g., 2-chloro-1,1,1-trifluoroethane) with HF in the gaseous phase at an elevated temperature in the presence of certain supported metal catalysts containing effective amounts of zinc. A catalyst of metal fluoride on a fluorinated alumina support having an atomic ratio of F to Al of at least 2.7:1 and containing .beta.-aluminum fluoride, is employed.
    Type: Grant
    Filed: March 20, 1991
    Date of Patent: June 14, 1994
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: David R. Corbin, V. N. Mallikarjuna Rao
  • Patent number: 5302765
    Abstract: A catalyic process is disclosed for producing CF.sub.3 CHClF from CF.sub.3 CH.sub.2 F by chlorination at elevated temperature. Suitable catalysts for the process include carbon catalysts and catalysts wherein halides of certain metals (La, Zn, Cu, Cr, Ru, Rh, and/or Pt) are supported on carbon.
    Type: Grant
    Filed: May 29, 1992
    Date of Patent: April 12, 1994
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Leo E. Manzer, V. N. Mallikarjuna Rao, Frank J. Weigert
  • Patent number: 5300711
    Abstract: A process is disclosed for producing HCFC-123, HCFC-124 and/or HFC-125 which includes reacting certain tetrahaloethylene starting materials (e.g., tetrachloroethylene) with HF in the gaseous phase at an elevated temperature in the presence of certain supported metal catalysts containing effective amounts of zinc. A catalyst of metal fluoride on a fluorinated alumina support having an atomic ratio of F to Al of at least 2.7:1 and containing .beta.-aluminum fluoride, is employed.
    Type: Grant
    Filed: March 20, 1991
    Date of Patent: April 5, 1994
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: David R. Corbin, V. N. Mallikarjuna Rao
  • Patent number: 5300710
    Abstract: A process is disclosed for producing HCFC-124 and HFC-125 which includes reacting certain pentahaloethane starting materials (e.g., CF.sub.3 CHCl.sub.2) in the gaseous phase at an elevated temperature in the presence of certain supported metal catalysts containing effective amounts of zinc. A catalyst of metal fluoride on a fluorinated alumina support having an atomic ratio of F to Al of at least 2.7:1 and containing .beta.-aluminmum fluoride, is employed.
    Type: Grant
    Filed: March 20, 1991
    Date of Patent: April 5, 1994
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: David R. Corbin, V. N. Mallikarjuna Rao
  • Patent number: 5268122
    Abstract: A catalyic process is disclosed for producing fluorine-substituted hydrocarbon products of the formulae RCH.sub.2 CF.sub.2 R and RFC.dbd.CHR at an elevated temperature, from compounds of the formula RCHFCHFR, where each R is independently selected from the group consisting of --CF.sub.3, --CF.sub.2 CF.sub.3 and --CF.sub.2 CF.sub.2 CF.sub.3 or where both R groups of a formula together are --(CF.sub.2).sub.2 --, --(CF.sub.2).sub.3 -- or --(CF.sub.2).sub.4 --. Suitable catalysts include carbon catalysts and catalysts containing at least one compound of a selected metal (e.g., Na, K, Rb, Cs, Y, La, Ce, Pr, Nd, Sm, Cr, Fe, Co, Rh, Ni, Cu, and/or Zn) supported on carbon.The saturated gem-dihydro- products may also be produced by hydrofluorinating the corresponding olefinic product over such catalysts at an elevated temperature, and can be combined with various other miscible solvents to form compositions useful for cleaning. Compounds such as CF.sub.3 CF.sub.2 CH.sub.2 CF.sub.2 CF.sub.3, CF.sub.3 CF.sub.2 CH.sub.
    Type: Grant
    Filed: August 28, 1991
    Date of Patent: December 7, 1993
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: V. N. Mallikarjuna Rao, Frank J. Weigert, Carl G. Krespan
  • Patent number: 5258561
    Abstract: A chlorofluorination process is disclosed which employs a catalyst comprising chromium oxide for producing halohydrocarbons of the formula CHXFCF.sub.3 (where X is selected from Cl and F). The process is characterized by feeding a combination of components comprising, (i) at least one halohydrocarbon starting compound of the formula CY.sub.3 CH.sub.2 R.sup.1 (where R.sup.1 is selected from the group of H and F and each Y is independently selected from the group of Cl and F), (ii) hydrogen fluoride and (iii) chlorine to a reaction zone; contacting said combination of compounds in said reaction zone with a catalyst comprising chromium oxide at an elevated temperature to produce reaction zone products containing halohydrocarbon reaction products of the formula CHXFCF.sub.3 together with halohydrocarbons of the formula CZ.sub.3 CHR.sup.2 R.sup.3 (wherein R.sup.2 is selected from the group of H and Cl, R.sup.
    Type: Grant
    Filed: November 6, 1992
    Date of Patent: November 2, 1993
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Mario J. Nappa, V. N. Mallikarjuna Rao
  • Patent number: 5208397
    Abstract: Mixtures of halocarbons which contain fluorine and chlorine and/or bromine (e.g. a mixture of CCl.sub.2 FCF.sub.3 with CClF.sub.2 CF.sub.3, CCl.sub.2 F.sub.2, CClF.sub.2 CClF.sub.2 or CHClF.sub.2) are contacted with hydrogen in the presence of silicon carbide and/or a metal selected from aluminum, molybdenum, titanium, nickel, iron or cobalt (or their alloys) at temperatures of 350.degree. to 700.degree. C. and pressures of 0 to 1000 psig to obtain a product mixture which substantially corresponds in terms of the distribution of fluorine substituents on carbon atoms with the mixture of halocarbon starting materials.
    Type: Grant
    Filed: April 9, 1991
    Date of Patent: May 4, 1993
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: William H. Manogue, V. N. Mallikarjuna Rao
  • Patent number: 5196615
    Abstract: Process for the preparation of fluorinated alkanes by contacting halogenated alkanes with HF in the presence of TaCl.sub.5 or TaBr.sub.5.
    Type: Grant
    Filed: August 22, 1990
    Date of Patent: March 23, 1993
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: V. N. Mallikarjuna Rao
  • Patent number: 5177273
    Abstract: A vapor phase process is disclosed for producing HCFC-225s, HCFC-235s, HCFC-226s, HFC-236s, and HFC-227s by reacting certain three-carbon reactants containing at least one less fluorine than, and at least as many hydrogen substituents as the desired product (e.g. propane propylene, allene or methylacetylene) with Cl.sub.2 and HF in the presence of a catalyst consisting essentially of chromium oxide or of chromium oxide which is combined with a refractory oxide, fluorinated and/or modified with manganese, iron, cobalt, nickel, copper and/or zinc. The temperature and contact time for the reaction are chosen to provide a product having the desired fluorine and hydrogen content.
    Type: Grant
    Filed: February 1, 1991
    Date of Patent: January 5, 1993
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Douglas W. Bruhnke, Jan J. Lerou, V. N. Mallikarjuna Rao, William C. Seidel, Frank J. Weigert
  • Patent number: 5171902
    Abstract: The compounds CF.sub.3 CHFCHFCF.sub.2 CF.sub.3, CF.sub.3 CH.sub.2 CHFCF.sub.2 CF.sub.3, CF.sub.3 CHFCH.sub.2 CF.sub.2 CF.sub.3, CF.sub.3 CHFCHFCF.sub.2 CF.sub.2 CF.sub.3, CF.sub.3 CH.sub.2 CHFCF.sub.2 CF.sub.2 CF.sub.3, CF.sub.3 CHFCH.sub.2 CF.sub.2 CF.sub.2 CF.sub.3, CF.sub.3 CF.sub.2 CH.sub.2 CHFCF.sub.2 CF.sub.3, CF.sub.3 CF.sub.2 CHFCHFCF.sub.2 CF.sub.2 CF.sub.3, CF.sub.3 CHFCHFCF.sub.2 CF.sub.2 CF.sub.2 CF.sub.3, CF.sub.3 CHFCH.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.3, CF.sub.3 CH.sub.2 CHFCF.sub.2 CF.sub.2 CF.sub.2 CF.sub.3, CF.sub.3 CF.sub.2 CHFCH.sub.2 CF.sub.2 CF.sub.2 CF.sub.3, and CF.sub.3 CF.sub.2 CH.sub.2 CHFCF.sub.2 CF.sub.2 CF.sub.3 ; and compositions thereof.
    Type: Grant
    Filed: October 11, 1990
    Date of Patent: December 15, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Carl G. Krespan, V. N. Mallikarjuna Rao
  • Patent number: 5146018
    Abstract: A process for the hydrogenolysis and/or dehydrohalogenation of fluorohalocarbons and/or fluorohalohydrocarbons by reacting the fluorohalocarbons and/or fluorohalohydrocarbons with a source of hydrogen in the presence of a catalyst, the improvement comprising utilizing a rhenium-containing catalyst, which may, optionally, contain at least one Group VIII metal and may, optionally, be supported.
    Type: Grant
    Filed: June 26, 1991
    Date of Patent: September 8, 1992
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Carl S. Kellner, V. N. Mallikarjuna Rao, Frank J. Weigert
  • Patent number: 5120883
    Abstract: A catalyic process is disclosed for producing CCl.sub.3 CF.sub.3 from CHCl.sub.2 CF.sub.3, CH.sub.2 ClCF.sub.3 and/or CH.sub.3 CF.sub.3 by chlorination at elevated temperature. Suitable catalysts for the process include carbon catalysts and catalysts wherein halides of certain metals (Zn, Cu, Cr, Ru, Rh, and/or Pt) are supported on carbon.
    Type: Grant
    Filed: August 26, 1991
    Date of Patent: June 9, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: V. N. Mallikarjuna Rao, Frank J. Weigert, Leo E. Manzer
  • Patent number: 5094988
    Abstract: This invention provides a process for the regeneration and/or activation of a noble catalyst comprising contacting said catalyst with an atmosphere comprising a fluorohalocarbon and/or a fluorohydrocarbon of the formula, C.sub.n H.sub.m F.sub.p X.sub.q, wherein X is chlorine and/or bromine; n is an integer from 1 to 6; m is an integer from 0 to 6, provided that m can be no more than the total n in the compound; p and q are integers from 1-13 when the compound is acyclic and integers from 1-11 when the compound is cyclic, provided that the fluorohalocarbon and/or fluorohalohydrocarbon always contains at least one chlorine or bromine atom and provided that m+p+q=2n+2 when the compound is acyclic and that m+p+q=2n when the compound is cyclic, at a temperature in excess of 200.degree. C.
    Type: Grant
    Filed: September 20, 1990
    Date of Patent: March 10, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Carl S. Kellner, Jan J. Lerou, V. N. Mallikarjuna Rao, Klaus G. Wuttke
  • Patent number: 5094773
    Abstract: Azeotropes of HF and 2,2-dichloro-1,1,1-trifluoroethane and of HF and 2-chloro-1,1,1,2-tetrafluoroethane. Process for the separation of hydrogen fluoride (HF), 2,2-dichloro-1,1,1-trifluoroethane (FC-123), and/or 2-chloro-1,1,1,2-tetrafluoroethane (FC-124) from mixtures containing them by controlling the molar ratio of HF/FC-123 in the mixture prior to subjecting the mixture to azeotropic distillation.
    Type: Grant
    Filed: April 9, 1990
    Date of Patent: March 10, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Leo E. Manzer, V. N. Mallikarjuna Rao, Richard T. Rockwell, Michael A. Sisk, Edwin J. Warwas, Roy Winteringham
  • Patent number: 5068473
    Abstract: A process for the hydrogenolysis and/or dehydrohalogenation of fluorohalocarbons and/or fluorohalohydrocarbons by reacting the fluorohalocarbons and/or fluorohalohydrocarbons with a source of hydrogen in the presence of a catalyst, the improvement comprising utilizing a rhenium-containing catalyst, which may, optionally, contain at least one Group VIII metal and may, optionally, be supported.
    Type: Grant
    Filed: October 17, 1990
    Date of Patent: November 26, 1991
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Carl S. Kellner, V. N. Mallikarjuna Rao, Frank J. Weigert
  • Patent number: 5030372
    Abstract: Gas phase and liquid phase processes are disclosed which use interconversion of CF.sub.3 CHFCl and CF.sub.2 HCF.sub.2 Cl in contact with catalyst consisting essentially of halided aluminum oxide and/or aluminum halide at elevated temperatures to increase the mole ratio of one of said compounds in a composition relative to the other. Also disclosed in use of said interconversion along with hydrogenolysis in processes for producing mixtures of CF.sub.3 CH.sub.2 F and CF.sub.2 HCF.sub.2 H from certain compositions comprising CF.sub.2 HCF.sub.2 Cl such that the mole ratio of CF.sub.3 CH.sub.2 F to CF.sub.2 HCF.sub.2 H in the product mixtures produced from said compositions may be increased or decreased.
    Type: Grant
    Filed: July 31, 1990
    Date of Patent: July 9, 1991
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: William H. Manogue, V. N. Mallikarjuna Rao, Frank J. Weigert
  • Patent number: 5026930
    Abstract: An improved gas-phase process for the manufacture of 1,1-difluoro-1,2-dichloroethane and/or 1-fluoro-1,1,2-trichloroethane by contacting a suitable trihaloethylene and/or a tetrahaloethane with hydrogen fluoride in the presence of a metal in combination with a high fluorine content aluminum-containing compound, the reaction being preferably conducted under controlled conditions whereby the production of 1,1,1-trifluorochloroethane is minimized.
    Type: Grant
    Filed: January 16, 1990
    Date of Patent: June 25, 1991
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Leo E. Manzer, V. N. Mallikarjuna Rao