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: 6762333
    Abstract: The fluorine content of an acyclic saturated compound of the formula CnFaXbHc (wherein each X is independently selected from the group consisting of Cl and Br, and wherein n is 1 to 6, a is 1 to 13, b is 0 to 12, c is 1 to 9, and a+b+c 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 1:1.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: July 13, 2004
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Leo Ernest Manzer, V. N. Mallikarjuna Rao, Steven Henry Swearingen
  • Patent number: 6683226
    Abstract: A process for the manufacture of CF3CF═CF2 is disclosed. The process involves contacting 2,3-dichloro-1,1,1,2,3,3-hexafluoropropane with at least 0.1 mole of hydrogen in a reaction vessel of titanium, nickel or iron or their alloys, which is either empty or packed with particles or formed shapes of titanium, nickel or iron or their alloys, at a temperature within the range of from about 350° C. to about 600° C. and for a time sufficient to produce hexafluoropropene. Also disclosed are compositions which comprise hydrogen fluoride in combination with an effective amount of CClF2CClFCF3 to form an azeotrope or azeotrope-like composition with hydrogen fluoride. The compositions contain from about 8.7 to 33.6 mole percent CClF2CClFCF3.
    Type: Grant
    Filed: February 14, 2003
    Date of Patent: January 27, 2004
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Allen Capron Sievert, V. N. Mallikarjuna Rao
  • Patent number: 6677493
    Abstract: A process is disclosed for the separation of a mixture of HF and CF3CClFCF3. The process involves placing the mixture in a separation zone at a temperature of from about −30° C. to about 100° C. and at a pressure sufficient to maintain the mixture in the liquid phase, whereby an organic-enriched phase comprising less than 50 mole percent HF is formed as the bottom layer and an HF-enriched phase comprising more than 90 mole percent HF is formed as the top layer. The organic-enriched phase can be withdrawn from the bottom of the separation zone and subjected to distillation in a distillation column to recover essentially pure CF3CClFCF3. The distillate comprising HF and CF3CClFCF3 can be removed from the top of the distillation column while essentially pure CF3CClFCF3 can be recovered from the bottom of the distillation column. The HF-enriched phase can be withdrawn from the top of the separation zone and subjected to distillation in a distillation column.
    Type: Grant
    Filed: April 1, 1999
    Date of Patent: January 13, 2004
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Ralph Newton Miller, V. N. Mallikarjuna Rao, Steven H. Swearingen
  • Patent number: 6635187
    Abstract: A process is disclosed for producing compositions including (a) a compound selected from the group consisting of CHF2CF3, CHF2CHF2, CH2FCF3, CH3CF3, CH3CHF2, CH2FCF2CHF2 and CHF2CF2CF2CHF2 and (b) at least one saturated halogenated hydrocarbon and/or ether having the formula: CnH2n+2-a-bClaFbOc wherein n is an integer from 1 to 4, a is an integer from 0 to 2n+1, b is an integer from 1 to 2n+2-a, and c is 0 or 1, provided that when c is 1 then n is an integer from 2 to 4, and provided that component (b) does not include the selected component (a) compound, wherein the molar ratio of component (b) to component (a) is between about 1:99 and a molar ratio of HF to component (a) in an azeotrope or azeotrope-like composition of component (a) with HF.
    Type: Grant
    Filed: November 15, 2000
    Date of Patent: October 21, 2003
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Barry A. Mahler, V. N. Mallikarjuna Rao, Allen Capron Sievert
  • Publication number: 20030122103
    Abstract: A process for the manufacture of CF3CF═CF2 is disclosed. The process involves contacting 2,3-dichloro-1,1,1,2,3,3-hexafluoropropane with at least 0.1 mole of hydrogen in a reaction vessel of titanium, nickel or iron or their alloys, which is either empty or packed with particles or formed shapes of titanium, nickel or iron or their alloys, at a temperature within the range of from about 350° C. to about 600° C. and for a time sufficient to produce hexafluoropropene. Also disclosed are compositions which comprise hydrogen fluoride in combination with an effective amount of CClF2CClFCF3 to form an azeotrope or azeotrope-like composition with hydrogen fluoride. The compositions contain from about 8.7 to 33.6 mole percent CClF2CClFCF3.
    Type: Application
    Filed: February 14, 2003
    Publication date: July 3, 2003
    Inventors: Allen Capron Sievert, V.N. Mallikarjuna Rao
  • Patent number: 6548720
    Abstract: A process is disclosed for producing the pentfluropropenes of the formula CF3CX═CF2, where X is H or Cl. The process involves hydrodehalogenating CF3CCl2CF3 with hydrogen at an elevated temperature in the vapor phase over a catalyst comprising an elemental metal, metal oxide, metal halide and/or metal oxyhalide (the metal being copper, nickel, chromium and the halogen of said halides and said oxyhalides being fluorine and/or chlorine. Processes for producing the hydrofluorocarbons CF3CH2CHF2, CF3CHFCF3 and CF3CH2CF3 are also disclosed which involve (a) hydrodehalogenating CF3CCl2CF3 with the hydrogen as indicated above to produce a product comprising CF3CCl═CF2, CF3CH═CF2, HCl and HF; and (b) either reacting the CF3CCl═CF2 and/or CF3CH═CF2 produced in (a) in the vapor phase with hydrogen to produce CF3CH2CHF2, reacting CF3CCl═CF2 produced in (a) with HF to produce CF3CHFCF3, or reacting the CF3CH═CF2produced in (a) with HF to produce CF3CH2CF3.
    Type: Grant
    Filed: January 30, 2002
    Date of Patent: April 15, 2003
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: William H. Manogue, V. N. Mallikarjuna Rao, Allen Capron Sievert, Steven H. Swearingen
  • Patent number: 6540933
    Abstract: A process for the manufacture of CF3CF═CF2 is disclosed. The process involves contacting 2,3-dichloro-1,1,1,2,3,3-hexafluoropropane with at least 0.1 mole of hydrogen in a reaction vessel of titanium, nickel or iron or their alloys, which is either empty or packed with particles or formed shapes of titanium, nickel or iron or their alloys, at a temperature within the range of from about 350° C. to about 600° C. and for a time sufficient to produce hexafluoropropene. Also disclosed are compositions which comprise hydrogen fluoride in combination with an effective amount of CClF2CClFCF3 to form an azeotrope or azeotrope-like composition with hydrogen fluoride. The compositions contain from about 8.7 to 33.6 mole percent CClF2CClFCF3.
    Type: Grant
    Filed: November 27, 2000
    Date of Patent: April 1, 2003
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Allen Capron Sievert, V. N. Mallikarjuna Rao
  • Publication number: 20020115895
    Abstract: A process is disclosed for producing the pentfluropropenes of the formula CF3CX=CF2, where X is H or Cl. The process involves hydrodehalogenating CF3CCl2CF3 with hydrogen at an elevated temperature in the vapor phase over a catalyst comprising an elemental metal, metal oxide, metal halide and/or metal oxyhalide (the metal being copper, nickel, chromium and the halogen of said halides and said oxyhalides being fluorine and/or chlorine. Processes for producing the hydrofluorocarbons CF3CH2CHF2, CF3CHFCF3 and CF3CH2CF3 are also disclosed which involve (a) hydrodehalogenating CF3CCl2CF3 with the hydrogen as indicated above to produce a product comprising CF3CCl=CF2, CF3CH=CF2, HCl and HF; and (b) either reacting the CF3CCl=CF2 and/or CF3CH=CF2 produced in (a) in the vapor phase with hydrogen to produce CF3CH2CHF2, reacting CF3CCl=CF2 produced in (a) with HF to produce CF3CHFCF3, or reacting the CF3CH=CF2produced in (a) with HF to produce CF3CH2CF3.
    Type: Application
    Filed: January 30, 2002
    Publication date: August 22, 2002
    Inventors: William H. Manogue, V.N. Mallikarjuna Rao, Allen Capron Sievert, Steven H. Swearingen
  • Patent number: 6376727
    Abstract: Disclosed are azeotropic compositions comprising CF3CHFCF3 and HF. Also disclosed are compositions and a process for producing compositions comprising (c1) CF3CHFCF3, CF3CH2CF3, or CHF2CH2CF3, and (c2) at least one saturated halogenated hydrocarbon and or ether having the formula: CnH2n+2−a−bClaFbOc wherein n is an integer from 1-4, a is an integer from 0-2n+1, b is an integer from 1-2n+2a, and c is 0 or 1, provided that when c is 1 then n is an integer from 2-4, and provided that component (c2) does not include the selected component (c1) compound, wherein the molar ratio of component (c2) to component (c1) is between about 1:99 and a molar ratio of HF to component (c1) in an azeotrope or azeotrope-like composition of component (c1) with HF.
    Type: Grant
    Filed: August 19, 1999
    Date of Patent: April 23, 2002
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: V. N. Mallikarjuna Rao, Allen Capron Sievert
  • Patent number: 6369284
    Abstract: A process is disclosed for the manufacture of a pentafluoropropene of the formula: CFX═CYCF3 where X is selected from H and F and where Y is F when X is H and Y is H when X is F. The process involves contacting a hexafluoropropane of the formula: CF2XCHYCF3 at a temperature of from about 200° C. to 500° C. with a catalyst, optionally in the presence of an inert gas. Suitable catalysts include (1) catalysts of (a) at least one compound selected from the oxides, fluorides and oxyfluorides of magnesium, zinc and mixtures of magnesium and zinc, and optionally (b) at least one compound selected from the oxides, fluorides and oxyfluorides of aluminum; provided that the atomic ratio of aluminum to the total of magnesium and zinc in said catalyst is about 1:4, or less (e.g., 1:9), (2) lanthanum fluoride, (3) fluorided lanthanum oxide, (4) activated carbon, and (5) three-dimensional matrix carbonaceous materials.
    Type: Grant
    Filed: July 26, 1999
    Date of Patent: April 9, 2002
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Mario Joseph Nappa, V.N.Mallikarjuna Rao
  • Publication number: 20020035300
    Abstract: A process is disclosed for producing the pentafluoropropenes of the formula CF 3 CX═CF 2 , where X is H or Cl. The process involves hydrodehalogenating CF 3 CCl 2 CF 3 with hydrogen at an elevated temperature in the vapor phase over a catalyst comprising an elemental metal, metal oxide, metal halide and/or metal oxyhalide (the metal being copper, nickel, chromium and the halogen of said halides and said oxyhalides being fluorine and/or chlorine).
    Type: Application
    Filed: August 19, 1999
    Publication date: March 21, 2002
    Inventors: V.N. MALLIKARJUNA RAO, ALLEN CAPRON SIEVERT
  • Patent number: 6329559
    Abstract: A process is disclosed for the manufacture of CF3CF═CF2, and optionally a least one compound selected from CF3CH2CF3 and CF3CHFCHF2. The process involves contacting a reactor feed including a precursor stream of at least one halogenated propane of the formula CX3CH2CHyX(3−y) and/or halogenated propene of the formula CX3CH═CHyX(2−y), where each X is Cl or F and y is 0, 1 or 2 (provided that the average fluorine content of the precursor stream is no more than 5 fluorine substituents per molecule) with HF and Cl2 in a chlorofluorination reaction zone containing a fluorination catalyst and operating at a temperature between about 150° C. and 400° C.
    Type: Grant
    Filed: November 27, 2000
    Date of Patent: December 11, 2001
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Allen Capron Sievert, V. N. Mallikarjuna Rao, Francis J. Walczak
  • Patent number: 6291729
    Abstract: A highly selective process is disclosed for the hydrogenolysis of 2,2-dichlorohexafluoropropane (i.e., CFC-216aa or CF3CCl2CF3) to 2,2-dihydrohexafluoropropane (i.e., HFC-236fa or CF3CH2CF3) and 2-chloro-2-hydrohexafluoropropane (i.e., 226da or CF3CHClCF3). The process involves reacting the starting material with hydrogen at an elevated temperature of about 300° C. or less in the presence of a catalyst containing a catalytically effective amount of palladium supported on a support of fluorinated alumina and/or aluminum fluoride.
    Type: Grant
    Filed: December 8, 1994
    Date of Patent: September 18, 2001
    Assignee: E. I. du Pont de Nemours and Company
    Inventor: V. N. Mallikarjuna Rao
  • Patent number: 6281396
    Abstract: A halocarbon product made from the reaction of excess hydrogen fluoride with a halocarbon, containing excess hydrogen fluoride as an azeotrope is purified by fluorination in the presence of additional halocarbon or halo-olefin.
    Type: Grant
    Filed: August 11, 1995
    Date of Patent: August 28, 2001
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Leo Ernest Manzer, V. N. Mallikarjuna Rao
  • Patent number: 6281395
    Abstract: A process is disclosed for the manufacture of CF3CHFCF3 containing less than 0.01 ppm (CF3)2C═CF2. The process involves (a) contacting hexafluoropropene in the vapor phase at a temperature of less than about 260° C. with hydrogen fluoride in the presence of a selected fluorination catalyst or produce a product containing less than 10 parts (CF3)2C═CF2 per million parts of CF3CHFCF3; and (b) treating the product of (a) as necessary to remove excess (CF3)2C═CF2. Suitable catalysts include: (i) an activated carbon treated to contain from about 0.1 to about 10 weight % added alkali or alkaline earth metals, (ii) three dimensional matrix porous carbonaceous materials, (iii) supported metal catalysts comprising trivalent chromium, and (iv) unsupported chrome oxide prepared by the pyrolysis of (NH4)2Cr2O7.
    Type: Grant
    Filed: April 1, 1999
    Date of Patent: August 28, 2001
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Mario Joseph Nappa, V. N. Mallikarjuna Rao, Allen Capron Sievert
  • Patent number: 6274780
    Abstract: A process is disclosed for changing the fluorine content of halogenated hydrocarbons containing from 1 to 6 carbon atoms, in the presence of a multiphase catalyst. The process involves producing the catalyst by heating a single phase solid catalyst precursor having the formula (NH3)6Cr2−xMxF6 (where x is in the range of 0.1 to 1 and M is at least one metal selected from the group consisting of Al, Sc, V, Fe, Ga and In) to about 400° or less to produce a multiphase composition wherein a phase containing crystalline M fluoride is homogeneously dispersed with a phase containing chromium fluoride. Also disclosed are multiphase catalyst compositions consisting essentially of chromium fluoride and a crystalline fluoride of at least one metal selected from the above group (provided the atom percent of Cr is at least equal to the atom percent of the crystalline fluoride metals). Phases of the crystalline fluorides are homogeneously dispersed with phases of the chromium fluoride.
    Type: Grant
    Filed: July 9, 1996
    Date of Patent: August 14, 2001
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: V. N. Mallikarjuna Rao, Munirpallam A. Subramanian
  • Patent number: 6274781
    Abstract: A process for producing difluoromethane is disclosed which includes the step of contacting a gaseous mixture containing CH2Cl2 and hydrogen fluoride with a catalyst containing a catalytically effective amount of trivalent chromium supported on a carbon having an ash content of less than 0.5 percent by weight, at a temperature of from about 180 ° C. to about 375° C. The catalyst and temperature conditions of this process allow the concurrent reaction CCl3CF3 with HF to form CCl2FCF3. CH2ClF and unreacted CH2Cl2, each of which may be recovered as an azeotrope with HF, may be recycled.
    Type: Grant
    Filed: November 1, 1993
    Date of Patent: August 14, 2001
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Paul S. Furmanek, David A. Glasscock, Michael Keane, Jr., Barry A. Mahler, V. N. Mallikarjuna Rao
  • Patent number: 6262321
    Abstract: This invention relates to a process for the production of vinyl fluoride by dehydrofluorination of 1,1-difluoroethane in the presence of a catalyst containing magnesium and/or zinc.
    Type: Grant
    Filed: May 18, 1999
    Date of Patent: July 17, 2001
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Mario Joseph Nappa, V. N. Mallikarjuna Rao
  • Patent number: 6224781
    Abstract: A process is disclosed for producing compositions including (a) a compound selected from the group consisting of CHF2CF3, CHF2CHF2, CH2FCF3, CH3CF3, CH3CHF2, CH2FCF2CHF2 and CHF2CF2CF2CHF2 and (b) at least one saturated halogenated hydrocarbon and/or ether having the formula: CnH2n+2−a−bClaFbOc wherein n is an integer from 1 to 4, a is an integer from 0 to 2n+1, b is an integer from 1 to 2n+2−a, and c is 0 or 1, provided that when c is 1 then n is an integer from 2 to 4, and provided that component (b) does not include the selected component (a) compound, wherein the molar ratio of component (b) to component (a) is between about 1:99 and a molar ratio of HF to component (a) in an azeotrope or azeotrope-like composition of component (a) with HF.
    Type: Grant
    Filed: August 20, 1998
    Date of Patent: May 1, 2001
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Barry A. Mahler, V. N. Mallikarjuna Rao, Allen Capron Sievert, Munirpallam A. Subramanian, Edwin James Warwas
  • Patent number: 6218587
    Abstract: Catalytic hydrogenolysis of fluorohalocarbons (e.g., CFCs) and fluorohalohydrocarbons (e.g., HCFCs), using low-phosphorous, low-sulfur catalysts of Re, Co, Ni, Ru, Rh, Pd, Os, Ir, and/or Pt on carbon. Preferred catalysts are acid-washed and also have a low content of potassium, sodium and iron.
    Type: Grant
    Filed: September 27, 1994
    Date of Patent: April 17, 2001
    Assignee: E. I. du Pont de Nemours and Company
    Inventor: V. N. Mallikarjuna Rao