Patents by Inventor Charles J. Shields

Charles J. Shields 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).

  • Purification of 1,1,1,2-tetrafluoroethane
    Patent number: 5288930
    Abstract: A process for the removal of 1-chloro-2,2-difluoroethylene from 1,1,1,2-tetrafluoroethane by contacting the mixture with a zeolite having a mean pore size in the range of 3.5 .ANG. and 4.8 .ANG. and having potassium as counter cation.The zeolite having potassium as counter-cation may be produced by cation-exchange with a commercially available zeolite, for example AW-500.
    Type: Grant
    Filed: July 12, 1993
    Date of Patent: February 22, 1994
    Assignee: Imperial Chemical Industries PLC
    Inventors: Charles J. Shields, Adrian S. Swindells
  • Process for the separation of halogenated hydrocarbons by extractive distillation
    Patent number: 5200431
    Abstract: Method for separating 1,1,1,2-tetrafluoroethane from a mixture thereof with chlorine-containing halogenated hydrocarbons such as HCFC's 1122, 124, 114, 114a and 133a which comprises adding an extraction agent to the mixture and extractively distilling the mixture in an extractive distillation zone from which HFA 134a containing less than 10 ppm of chlorinated contaminants is recovered. Suitable extraction agents include trichloroethylene, perchloroethylene, alpha-pinene and cyclohexane.
    Type: Grant
    Filed: August 21, 1991
    Date of Patent: April 6, 1993
    Assignee: Imperial Chemical Industries PLC
    Inventors: Pravin K. Dattani, John D. Scott, Barry W. Farrant, Charles J. Shields