Patents Represented by Attorney Paula S. Ruhr

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  • Non-volatile 1,1,1-trichloroethane inhibitors
    Patent number: 4956017
    Abstract: A solvent, 1,1,1-trichloroethane, is stabilized against corrosion by the addition of a non-volatile polyether or complex polyether having an average molecular weight of from about 550 to about 8500. A painting formulation is prepared using the stabilized solvent.
    Type: Grant
    Filed: May 5, 1989
    Date of Patent: September 11, 1990
    Assignee: The Dow Chemical Company
    Inventors: Felipe A. Donate, George E. Hartwell, Bruce D. DeBolt, James G. Papajesk, Mark V. Buzzard
  • Gas flooding processing for the recovery of oil from subterranean formations
    Patent number: 4860828
    Abstract: In a gas flooding or miscible gas flooding operation, the sweep efficiency of the gas is improved using a mixture of an alkylated diphenyl sulfonate and an alpha-olefin sulfonate as the surfactants in a mobility control fluid or diverter.
    Type: Grant
    Filed: June 1, 1988
    Date of Patent: August 29, 1989
    Assignee: The Dow Chemical Company
    Inventors: Thomas Oswald, Ian A. Robson
  • Countercurrent multi-stage water crystallization of aromatic compounds
    Patent number: 4861919
    Abstract: A process for the purification of an aromatic compound, e.g. isopropylidenediphenol, comprising using a multi-stage countercurrent process wherein the crystals are melted by the addition of heat and water prior to each crystallization step and wherein one crystallization is accomplished at a pre-selected low temperature.
    Type: Grant
    Filed: February 29, 1988
    Date of Patent: August 29, 1989
    Assignee: The Dow Chemical Company
    Inventors: Lanny A. Robbins, Ben B. Gammill
  • Pyrite depressants useful in the separation of pyrite from coal
    Patent number: 4830740
    Abstract: The separation of coal from pyrite is enhanced by the use of an effective amount of a polymeric acid or salt thereof as a pyrite depressant in conventional flotation processes. The polymeric acid may be a carboxylic or sulfonic acid. An example of a salt of a polymeric acid useful in the process is sodium polyacrylate.
    Type: Grant
    Filed: April 19, 1988
    Date of Patent: May 16, 1989
    Assignee: The Dow Chemical Company
    Inventors: Richard R. Klimpel, Robert D. Hansen
  • Pyrite depressants useful in the separation of pyrite from coal
    Patent number: 4826588
    Abstract: The separation of coal from pyrite during a froth flotation process is enhanced by the use of an effective amount of a pyrite depressant. The depressant is a hydrophilic nitrogen-sulfur-containing compound.
    Type: Grant
    Filed: April 28, 1988
    Date of Patent: May 2, 1989
    Assignee: The Dow Chemical Company
    Inventors: Richard R. Klimpel, Robert D. Hansen, Michael J. Fazio
  • Flotation depressants
    Patent number: 4808301
    Abstract: The flotation of desired mineral ores is selectively depressed by the use of an effective amount of a polycarboxylic acid or salt thereof in a reverse flotation process. As an example, the flotation of iron-containing minerals, such as iron oxides or iron powder, is selectively depressed when compared to the flotation of silicate gangue thus facilitating the recovery of the desired mineral by the use of an effective amount of a polycarboxylic acid or salt thereof such as sodium polyacrylate.
    Type: Grant
    Filed: November 4, 1987
    Date of Patent: February 28, 1989
    Assignee: The Dow Chemical Company
    Inventors: Robert D. Hansen, Richard R. Klimpel