Patents by Inventor Dilip Kashelikar

Dilip Kashelikar 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).

  • Process for preparing 4-aminodiphenylamine
    Patent number: 9708243
    Abstract: A process for preparing 4-aminodiphenylamine (4-ADPA) comprising steps of coupling of aniline with nitrobenzene in presence of a suitable base, e.g. tetramethylammonium hydroxide (TMAH), hydrogenation of the coupling mass, phase separation, hydrogenation of azobenzene in the separated organic mass and fractional distillation for 4-ADPA recovery. An improvement in 4-ADPA recovery and a lowering of tar formation are obtained due to azobenzene reduction prior to 4-ADPA isolation. Also a gain in volume productivity of 4-ADPA is obtained by suitably altering the batch cycle time of the coupling reaction.
    Type: Grant
    Filed: March 7, 2012
    Date of Patent: July 18, 2017
    Assignee: NOCIL LIMITED
    Inventors: Chinmoy Nandi, Narendra Gangal, Pramod Purohit, Vinay Ketkar, Dilip Kashelikar
  • PROCESS FOR PREPARING 4-AMINODIPHENYLAMINE
    Publication number: 20150045584
    Abstract: A process for preparing 4-aminodiphenylamine (4-ADPA) comprising steps of coupling of aniline with nitrobenzene in presence of a suitable base, e.g. tetramethylammonium hydroxide (TMAH), hydrogenation of the coupling mass, phase separation, hydrogenation of azobenzene in the separated organic mass and fractional distillation for 4-ADPA recovery. An improvement in 4-ADPA recovery and a lowering of tar formation are obtained due to azobenzene reduction prior to 4-ADPA isolation. Also a gain in volume productivity of 4-ADPA is obtained by suitably altering the batch cycle time of the coupling reaction.
    Type: Application
    Filed: March 7, 2012
    Publication date: February 12, 2015
    Applicant: NOCIL LIMITED
    Inventors: Chinmoy Nandi, Narendra Gangal, Pramod Purohit, Vinay Ketkar, Dilip Kashelikar