Patents by Inventor Ranjit K. Roy

Ranjit K. Roy 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).

  • Publication number: 20030105350
    Abstract: A process for thermal benzylic bromination of a wide variety of benzylic compounds is described. Bromine is used as the bromination agent. Moderate temperatures are employed and the process can be used to produce in relatively pure form either mono- or dibrominated benzylic bromination products.
    Type: Application
    Filed: December 5, 2001
    Publication date: June 5, 2003
    Inventors: Max K. Mortensen, Hassan Y. Elnagar, Ranjit K. Roy, Robert C. Herndon,, Robert H. Allen, David A. Caillet
  • Patent number: 6096920
    Abstract: Palladium-catalyzed arylation of an olefin (e.g., ethylene) with an aromatic halide (e.g., 2-bromo-6-methoxynaphthalene, m-bromobenzophenone, or 4-isobutyl-1-bromobenzene) is conducted in specified media. After a special acid or base phase separation procedure, palladium-catalyzed carbonylation of the olefinically-substituted aromatic intermediate is conducted in specified media using CO and water or an alcohol to form arylalkylcarboxylic acid or ester or substituted arylalkylcarboxylic acid or ester (e.g., racemic 2-(6-methoxy-2-naphthyl)propionic acid, 2-(3-benzoylphenyl)propionic acid, or 2-(4-isobutylphenyl)propionic acid). Catalyst recovery procedures enabling recycle of catalyst residues and efficient recovery of amine hydrogen halide scavenger and solvent used in the arylation reaction are described, as well as novel, highly efficient methods of conducting the carbonylation reaction.
    Type: Grant
    Filed: July 8, 1998
    Date of Patent: August 1, 2000
    Assignee: Albemarle Corporation
    Inventors: Robert H. Allen, R. Carl Herndon, Jr., Kannappan C. Chockalingam, W. Dirk Klobucar, Gary D. Focht, Tse-Chong Wu, Gary D. Heidebrecht, Joseph D. McLean, Yaping Zhong, Thorsten W. Brockmann, Ronny W. Lin, William J. Layman, Jr., Ranjit K. Roy
  • Patent number: 5290945
    Abstract: This invention relates to a process for preparing a white bisimide product which principally contains N,N'-alkylene-bis(tetrabromophthalimide) or N,N'-bis(tetrabromophthalimide). The process features: providing, in a reaction vessel, a solution containing tetrabromophthalic anhydride and a solvent which contains at least about 15 weight percent of a mono-, di- or tri- carboxylic acid having a dissociation constant not higher than 1.0.times.10.sup.-3 at 25.degree. C.; forming a reaction mass by adding to the solution a diamine or a diamine salt formed by the partial or total diamine neutralization of a mono-, di- or tri- carboxylic acid having a dissociation constant not higher than 1.0.times.10.sup.-3 at 25.degree. C.
    Type: Grant
    Filed: August 11, 1992
    Date of Patent: March 1, 1994
    Assignee: Ethyl Corporation
    Inventors: Ranjit K. Roy, Ali M. Dadgar, Donald O. Hutchinson, Keith G. Anderson