Patents by Inventor Richard T. Stringfield

Richard T. Stringfield 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).

  • Patent number: 5683800
    Abstract: Disclosed is a surface-modified polymeric adsorbent material comprising a porous post-crosslinked polymer as a substrate and at least one surface-modifying polymer. The porous post-crosslinked polymer comprises a polymer of at least one monoethylenically unsaturated monomer, wherein the polymer has been post-crosslinked in a swollen state in the presence of a Friedel-Crafts catalyst. A process for preparing the surface-modified polymeric adsorbent materials, and the use of these materials in the separation of organic compounds, enantioselective synthesis and resolution of racemic mixtures are also disclosed.
    Type: Grant
    Filed: January 24, 1996
    Date of Patent: November 4, 1997
    Assignee: The Dow Chemical Company
    Inventors: Richard T. Stringfield, Mladen Ladika
  • Patent number: 5519064
    Abstract: Disclosed is a surface-modified polymeric adsorbent material comprising a porous post-crosslinked polymer as a substrate and at least one surface-modifying polymer. The porous post-crosslinked polymer comprises a polymer of at least one monoethylenically unsaturated monomer, wherein the polymer has been post-crosslinked in a swollen state in the presence of a Friedel-Crafts catalyst. A process for preparing the surface-modified polymeric adsorbent materials, and the use of these materials in the separation of organic compounds, enantioselective synthesis and resolution of racemic mixtures are also disclosed.
    Type: Grant
    Filed: October 28, 1994
    Date of Patent: May 21, 1996
    Assignee: The Dow Chemical Company
    Inventors: Richard T. Stringfield, Mladen Ladika
  • Patent number: 5460725
    Abstract: Polymeric adsorbent resins having both the high capacity associated with microporosity and the favorable kinetics associated with mesoporosity and macroporosity are useful for the chromatographic separation of organic compounds. These resins are prepared by alkylene bridging haloalkylated, porogen modified, cross-linked copolymers.
    Type: Grant
    Filed: March 3, 1995
    Date of Patent: October 24, 1995
    Assignee: The Dow Chemical Company
    Inventor: Richard T. Stringfield
  • Patent number: 5416124
    Abstract: Polymeric adsorbent resins having both the high capacity associated with microporosity and the favorable kinetics associated with mesoporosity and macroporosity are useful for the chromatographic separation of organic compounds. These resins are prepared by alkylene bridging haloalkylated, porogen modified, crosslinked copolymers.
    Type: Grant
    Filed: June 21, 1994
    Date of Patent: May 16, 1995
    Assignee: The Dow Chemical Company
    Inventor: Richard T. Stringfield
  • Patent number: 5021253
    Abstract: An improved method of decaffeinating and recovering such from caffeine containing materials without the use of organic solvents, except for regeneration of the resin, carbon or expensive extraction equipment, wherein the method comprises contacting an effective amount of an adsorbent resin with a liquid solution containing caffeine so as to adsorb caffeine from the liquid solution onto the adsorbent resin, where the adsorbent resin is made from a gel copolymer of a monovinyl aromatic monomer and a crosslinking monomer, where the gel copolymer has been post-crosslinked in the swollen state in the presence of a Friedel-Crafts catalyst and can be functionalized with hydrophilic groups if so desired.
    Type: Grant
    Filed: December 13, 1989
    Date of Patent: June 4, 1991
    Assignee: The Dow Chemical Company
    Inventors: Kari R. Dawson-Ekeland, Richard T. Stringfield
  • Patent number: 4965083
    Abstract: Bitter components, such as limonin, may be effectively removed from citrus juices, particularly navel orange juices, by contacting the juices with an adsorbent resin. The adsorbent resin is derived from a copolymer of a monoethylenically unsaturated monomer and a crosslinking monomer, where the copolymer has been post-crosslinked in the swollen state in the presence of a Friedel-Crafts catalyst and functionalized with hydrophilic groups. Preferably, the copolymers are styrene and divinylbenzene.
    Type: Grant
    Filed: March 20, 1989
    Date of Patent: October 23, 1990
    Assignee: The Dow Chemical Company
    Inventors: Seth I. Norman, Richard T. Stringfield, Christopher C. Gopsill
  • Patent number: 4950332
    Abstract: A process for decolorizing an aqueous sugar solution by contacting the solution with an absorbent resin, wherein the adsorbent resin is a macroporous copolymer being post-crosslinked in a swollen state in the presence of a Friedel-Crafts catalyst and functionalized with hydrophilic groups prior to contact with the aqueous sugar solution.
    Type: Grant
    Filed: February 27, 1989
    Date of Patent: August 21, 1990
    Assignee: The Dow Chemical Company
    Inventors: Richard T. Stringfield, H. Robert Goltz, Seth I. Norman, Upen J. Bharwada, Robert L. LaBrie