Patents by Inventor John W. Varwig

John W. Varwig 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).

  • Method for inhibiting the polymerization of acrylic acid
    Patent number: 5034156
    Abstract: A new and improved polymerization inhibitor composition, its method of manufacture, and its use in stabilizing the distillation of acrylic acid is made possible by the pre-oxygen-activation of N-nitrosophenylhydroxylamine in combination with hydroquinone mono-methyl-ether (often referred to as p-methoxyphenol) whereupon a synergistic performance of these components is disclosed.
    Type: Grant
    Filed: January 8, 1990
    Date of Patent: July 23, 1991
    Assignee: Mallinckrodt Specialty Chemicals Company
    Inventor: John W. Varwig
  • Method of making the ethanolamine salt of N-nitrosophenylhydroxylamine
    Patent number: 4898976
    Abstract: The ethanolamine salt of N-nitrosophenylhydroxylamine ("NPHA") is effective as a polymerization inhibitor for ethylenically unsaturated monomers. The ethanolamine salt can be prepared by reacting ethanolamine with the ammonium salt of NPHA. Advantageously, the ethanolamine salt is soluble in high concentrations in water and a variety of polar organic solvents.
    Type: Grant
    Filed: April 17, 1989
    Date of Patent: February 6, 1990
    Assignee: Mallinckrodt, Inc.
    Inventor: John W. Varwig
  • Ethanolamine salt of N-Nitrosophenylhydroxylamine and inhibiting polymerization therewith
    Patent number: 4772740
    Abstract: The ethanolamine salt of N-nitrosophenylhydroxylamine ("NPHA") is effective as a polymerization inhibitor for ethylenically unsaturated monomers. The ethanolamine salt can be prepared by reacting ethanolamine with the ammonium salt of NPHA. Advantageously, the ethanolamine salt is soluble in high concentrations in water and a variety of polar organic solvents.
    Type: Grant
    Filed: March 5, 1985
    Date of Patent: September 20, 1988
    Assignee: Mallinckrodt, Inc.
    Inventor: John W. Varwig