Patents by Inventor Velliyur N. M. Rao

Velliyur N. M. 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).

  • Method of removing olefinic impurities from hydrochlorofluorocarbons
    Patent number: 5569797
    Abstract: A process for preparing a hydrochlorofluorocarbon essentially free of olefinic impurities by selectively hydrogenating the olefinic impurities. The process may be controlled such that at least a portion of the hydrochlorofluorocarbon is converted into a fluorohydrocarbon.
    Type: Grant
    Filed: January 7, 1992
    Date of Patent: October 29, 1996
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Ta-Wei Fu, Velliyur N. M. Rao
  • Halocarbon hydrogenolysis
    Patent number: 5364992
    Abstract: Halocarbons such as CCl.sub.2 F, CF.sub.3 CFHCl.sub.2 or CF.sub.3 CFCl.sub.2 which contain chlorine and/or bromine 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pressures of 0 to 1000 psig to obtain a product wherein at least one chlorine or bromine in the starting material has been replaced by hydrogen.
    Type: Grant
    Filed: September 16, 1993
    Date of Patent: November 15, 1994
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: William H. Manogue, Velliyur N. M. Rao
  • Process for preparing butyrolactones and butanediols
    Patent number: 4782167
    Abstract: A process is disclosed for preparing butyrolactones, butanediols, and mixtures thereof comprising hydrogenating a hydrogenatable precursor in the presence of an aqueous reaction medium and a catalyst comprising palladium or combinations thereof with rhenium and at least one support selected from the oxides of titanium, zirconium, and hafnium.
    Type: Grant
    Filed: January 23, 1987
    Date of Patent: November 1, 1988
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Velliyur N. M. Rao
  • Hydrogenation of citric acid and substituted citric acids to 3-substituted tetrahydrofuran, 3- and 4-substituted butyrolactones and mixtures thereof
    Patent number: 4772729
    Abstract: A process is disclosed for preparing 3-substituted tetrahydrofuran, 3- and 4-substituted butyrolactones and mixtures thereof comprising hydrogenating a hydrogenatable precursor in the presence of an aqueous reaction medium and a catalyst comprising palladium and rhenium and at least one support selected from the group consisting of titanium oxide, zirconium oxide, and carbon.
    Type: Grant
    Filed: January 23, 1987
    Date of Patent: September 20, 1988
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Velliyur N. M. Rao
  • Beneficial use of water in catalytic conversion of formamides to isocyanates
    Patent number: 4683329
    Abstract: Water is fed together with formamide in vapor form in the production of isocyanates by silver-catalyzed oxidative dehydrogenation of formamides.
    Type: Grant
    Filed: April 16, 1986
    Date of Patent: July 28, 1987
    Assignee: E. I. DuPont de Nemours and Company
    Inventor: Velliyur N. M. Rao
  • Preparation of methyl isocyanate in a quartz reactor
    Patent number: 4620030
    Abstract: The process in which methyl isocyanate is prepared by the oxidative dehydrogenation of monomethyl formamide is improved by performing the reaction in a quartz reactor.
    Type: Grant
    Filed: October 23, 1984
    Date of Patent: October 28, 1986
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: George E. Heinsohn, Velliyur N. M. Rao
  • Multi-stage process with adiabatic reactors for the preparation of isocyanates
    Patent number: 4537726
    Abstract: The process in which organic isocyanates are prepared by the oxidative dehydrogenation of the corresponding formamides is improved by operating the process in at least two adiabatic reaction stages in series where no more than 0.7 equivalent of oxygen is fed to the first stage.
    Type: Grant
    Filed: November 9, 1984
    Date of Patent: August 27, 1985
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Velliyur N. M. Rao, George E. Heinsohn
  • Oxidation process and catalyst therefor
    Patent number: 4474997
    Abstract: An oxidation catalyst comprising boron phosphate impregnated with from 5 to 20 weight percent silver and its use to oxidize propylene, butene-1, butadiene-1,3 and methanol is disclosed. The oxidation takes place at from 200.degree. to 700.degree. C. Preferably water vapor is present.
    Type: Grant
    Filed: September 19, 1983
    Date of Patent: October 2, 1984
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Velliyur N. M. Rao
  • Catalytic conversion of formamides to isocyanates
    Patent number: 4469640
    Abstract: Monomethylformamide is converted to methyl isocyanate by reaction with oxygen in the presence of an inert diluent gas at 300.degree.-600.degree. C. using as catalyst sputtered silver or silver/gold on an inert, hard, nonporous support.
    Type: Grant
    Filed: March 14, 1983
    Date of Patent: September 4, 1984
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Peter F. Carcia, George E. Heinsohn, Velliyur N. M. Rao