Patents by Inventor Ishwar S. Bhardwaj

Ishwar S. Bhardwaj 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).

  • Preparation of polycarbonates with bioxyanion catalyst
    Patent number: 5288838
    Abstract: The invention discloses an improved process for the preparation of aryl polycarbonates. The process involves reacting aryl carbonate and dihydric phenol in the melt phase with a catalyst belonging to the class of quaternary ammonium bioxyanions having the general formula: ##STR1## Wherein `X` represents a carboxylate or a phenolate group or a mixture thereof and `R` represents alkyl or aryl.
    Type: Grant
    Filed: April 9, 1992
    Date of Patent: February 22, 1994
    Assignee: Council of Scientific & Industrial Research
    Inventors: Swaminathan Sivaram, Jagdish C. Sehra, Venkat S. Iyer, Ishwar S. Bhardwaj, Sheo Satish