Patents Represented by Attorney Robert R. Stringham
  • Patent number: 4048007
    Abstract: It has been found that solvent residues can be removed from aqueous paper pulps by stripping with economic volumes of gases. This can be done in conventional contacting equipment without reducing pulp consistencies below the levels typical of commercial paper-making operations. The solvents stripped out are recoverable and do not constitute a source of pollution.
    Type: Grant
    Filed: July 9, 1976
    Date of Patent: September 13, 1977
    Assignee: The Dow Chemical Company
    Inventor: J. Frank Valle-Riestra
  • Patent number: 4031100
    Abstract: It has been found that practical reaction rates can be attained without resort to the high temperatures previously employed in the preparation of 2,6-difluoropyridine from the corresponding dichloropyridine and KF, if:A. dimethyl sulfoxide is employed as the reaction medium;B. the reaction mixture contains solid KF particles and dissolved tetramethyl ammonium or phosphonium chloride;C. there is present in the reaction mixture less than 0.1 grams of acids, bases or organic hydroxy compounds and less than 1.0 grams of water, per 100 grams of solvent, andD. the reaction mixture is intensely stirred.
    Type: Grant
    Filed: August 23, 1976
    Date of Patent: June 21, 1977
    Assignee: The Dow Chemical Company
    Inventor: Thomas J. Giacobbe
  • Patent number: 4029657
    Abstract: Dichloropyrazino-oxazines of the formula ##STR1## wherein R is H or a C.sub.1 to C.sub.8 alkyl, alkenyl, cycloalkyl or cycloalkenyl radical, are disclosed. The compound in which R is H has utility as an intermediate for the compounds in which R is other than H. The latter compounds exhibit microbicidal, herbicidal or insecticidal activity. The compounds of the invention are readily prepared from tetrachloropyrazine and 2-aminoethanols of the formula R--NH--CH.sub.2 CH.sub.2 --OH.
    Type: Grant
    Filed: June 14, 1976
    Date of Patent: June 14, 1977
    Assignee: The Dow Chemical Company
    Inventor: Thomas J. Dietsche
  • Patent number: 4020230
    Abstract: Normally hydrophobic, polyethylene hollow fibers having contiguous microporosity are prepared by extruding a heated solution of a polyethylene and an ester from a hollow fiber spinnerette, simultaneously cooling and drawing the forming fibers to a ratio of up to 40 to 1, drawing the gelled fibers to an overall ratio of from about 1.5/1 to 800/1 and then removing the ester. The maximum pore radius ranges up to about 50A, and the fibers have gas permeabilities approaching 10.sup.-.sup.2 cc (STP) per cm.sup.2 per second per cm. Hg. transmembrane pressure differential. A significant increase in permeability over polyethylene hollow fibers made according to the teachings of the prior art is achieved.
    Type: Grant
    Filed: October 3, 1975
    Date of Patent: April 26, 1977
    Assignee: The Dow Chemical Company
    Inventors: Robert D. Mahoney, Stephen E. Schneider
  • Patent number: 4017120
    Abstract: Hot brines containing dissolved gases are produced from liquid-dominated geothermal wells by utilizing lift gases of essentially the same composition as said dissolved gases. The lift gas is separated from the produced brine and recycled. Heat is abstracted from the separated brine, which may be returned to the aquifer, processed for its mineral content or discarded. The gas lift is carried out under temperature and pressure conditions such that precipitation of minerals from the brine does not occur in the well bore. The problems which would result from the use of oxygen-containing and/or brine-soluble inert gases for the lifting operation are avoided. The problems attendant upon production of hot brines by pumping are also avoided.
    Type: Grant
    Filed: November 28, 1975
    Date of Patent: April 12, 1977
    Assignee: The Dow Chemical Company
    Inventors: Elwood L. Carlson, Albert A. Gunkler, Conrad O. M. Miller, H. Hunter Paalman
  • Patent number: 4016078
    Abstract: An improved header block for tubular membrane permeator modules, which has particular advantage for ultrafiltration operations, is disclosed. The header block is very compact and is formable by casting or molding and machining. In cooperation with a collector plate and end-plate, it provides both feed (or concentrate) and permeate manifolds. The high pressure differentials and/or cumbersome "turn arounds" or manifolds heretofore used are obviated by said block. A plurality of modules comprising such blocks may be joined side-by-side, in cooperation with appropriate side-plate and gasket means, to provide a variety of flow distributions and/or modes. The header block is uniquely appropriate for handling high volume flow rates required to ensure turbulent, high velocity flow of feed liquid within each permeator tube. The end plates preferably are transparent, to permit facile inspection of the permeate stream from each tube in each module.
    Type: Grant
    Filed: March 6, 1975
    Date of Patent: April 5, 1977
    Assignee: The Dow Chemical Company
    Inventor: George B. Clark
  • Patent number: 4006090
    Abstract: Elongated, polycrystalline particles of alpha iron oxide, characterized by an open, porous structure and consisting of hematite microcrystallites containing from 2 to 4 percent of sulfate are prepared by the reaction of lithium hydroxide and ferric sulfate in weakly acidic to neutral aqueous solution under at least autogenous pressures at temperatures in the range of 150.degree.-350.degree. C. The particles are readily converted to gamma iron oxide of good magnetic properites and also have utility as pigments and catalysts.
    Type: Grant
    Filed: July 21, 1975
    Date of Patent: February 1, 1977
    Assignee: The Dow Chemical Company
    Inventor: Henry Nelson Beck
  • Patent number: 4003982
    Abstract: Nitrogen trichloride normally explodes when heated to 95.degree. C. However, when a dilute solution of NCl.sub.3 in an inert solvent is heated to a temperature in the range of 105.degree.-140.degree., controlled decomposition to nitrogen and chlorine results. Nitrogen is innocuous and can be vented to the atmosphere. The chlorine is recovered. This method of NCl.sub.3 disposal is uncomplicated and non-polluting and constitutes a distinct improvement over prior art methods. The process of the invention finds utility primarily in destroying nitrogen trichloride formed as a by-product in the manufacture of trichloro isocyanuric acid.
    Type: Grant
    Filed: April 30, 1975
    Date of Patent: January 18, 1977
    Assignee: The Dow Chemical Company
    Inventors: Howard W. Hill, Ronald E. Hassall
  • Patent number: 4001215
    Abstract: The title compound is readily prepared in good yield by the reaction of acetylacetone with ammonia in methanol. It has fungicidal and insecticidal properties and, by reason of the number and variety of functional groups it contains, should be useful as an intermediate.
    Type: Grant
    Filed: March 12, 1976
    Date of Patent: January 4, 1977
    Assignee: The Dow Chemical Company
    Inventor: Thomas J. Dietsche
  • Patent number: 3987044
    Abstract: Insoluble association products are formed when solid 2,3-diamino-5,6-dihalopyrazines are contacted with liquid ketones of the structure R.sup.1 --CH.sub.2 --CO--CH.sub.2 --R.sup.2, wherein R.sup.1 and R.sup.2 are both H or together constitute a polymethylene chain of from 2 to 4 carbons. The isomeric 2,6-diamino-dihalopyrazines dissolve in the ketones. Thus, mixtures of the solid 2,3-diamino-dihalopyrazines with their isomers and/or other ketone-soluble materials can be resolved by contacting the mixtures with ketones of the preceding structure and separating the resultant solid and liquid phases. The association products constitute a novel composition of matter.
    Type: Grant
    Filed: August 18, 1975
    Date of Patent: October 19, 1976
    Assignee: The Dow Chemical Company
    Inventor: Yulan C. Tong
  • Patent number: 3968192
    Abstract: There is disclosed a method of repairing leaky permeability separatory devices, said devices comprising a membrane in the form of a multiplicity of hollow fibers having end portions potted in one or more resinous tubesheet bodies and terminating in an accessible surface of said tubesheet. According to the present invention, each surface opening communicating with a given leak in a tubesheet or fiber is selectively plugged by applying heat and pressure to the tubesheet and fiber material in the immediate vicinity of each such opening. The openings are first located by sealing the tubesheet/fiber assembly in an appropriately adapted jacket and applying pressure to a fluid in the portion of the jacket volume exterior to the fibers.
    Type: Grant
    Filed: April 19, 1974
    Date of Patent: July 6, 1976
    Assignee: The Dow Chemical Company
    Inventors: Sargent Glenn Hoffman, III, Frank Watkins Mather, III
  • Patent number: 3962260
    Abstract: Novel compounds having the formula ##SPC1##Wherein R is an alkyl group of 1 to 5 carbons, X is Br or Cl and Y is Cl or is Br except when X is Cl, are prepared by the reaction of a hydrazine source material with a corresponding compound of the formula ##SPC2##The product compounds are fungicidal in their own right and are readily oxidized to highly active trihalo-4-alkylsulfonyl pyridine fungicides.
    Type: Grant
    Filed: July 31, 1975
    Date of Patent: June 8, 1976
    Assignee: The Dow Chemical Company
    Inventors: Sven H. Ruetman, Richard N. Watson
  • Patent number: 3957781
    Abstract: The invention comprises a process for producing ring-perchlorinated aromatic carbocyclic and N-heterocyclic isocyanates by the vapor phase chlorination of the corresponding acetamido-substituted carbocycle or N-heterocycle. The resulting isocyanate may be further reacted with an active hydrogen-containing compound to form the corresponding carbamate, thiocarbamate, urea, or the like. The invention further comprises certain novel compounds made by such process, said compounds being useful as intermediates for plastic materials or as fine retardant additives in plastics.
    Type: Grant
    Filed: February 6, 1974
    Date of Patent: May 18, 1976
    Assignee: The Dow Chemical Company
    Inventor: Sven H. Ruetman
  • Patent number: 3956338
    Abstract: The invention is a genus of compounds of the formula ##SPC1##Wherein Y is H, M or RCO--; R is a primary or secondary C.sub.1 -C.sub.12 alkyl group, a C.sub.5 -C.sub.7 cycloalkyl group, phenyl or a C.sub.7 -C.sub.12 phenalkyl or alkylphenyl group and M is a metal or ammonium cation. The compounds have utility as intermediates and as herbicides.
    Type: Grant
    Filed: January 17, 1975
    Date of Patent: May 11, 1976
    Assignee: The Dow Chemical Company
    Inventors: Alin H. Gulbenk, Sven H. Ruetman