Patents by Inventor John G. Hefner

John G. Hefner 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: 5565547
    Abstract: Novel catalyst compositions comprising a cationic transition metal complex of the formula(Pd(II)S.sub.4-x L.sub.x).sup.+2 (A).sup.-n ywherein:Pd(II) is palladium having a valence of +2;S is a synthesis solvent;L is a monodendate, bidendate or tridendate ligand or ligands having one or more bonding sites;x is an integer from 1 to 3 and is equal to the total number of ligand bonding sites;A is a weakly or non-coordinating anion capable or stabilizing the complex in its cationic form; andn is 1 or 2 and y is 2 or 1;provided that(i) when n is 1, y is 2 and when n is 2, y is 1; and(ii) when the anion A is tetrafluoroborate, the organometallic complex is not (tris(acetonitrile) palladium(II) triphenylphosphine), bis(acetonitrile) palladium(II) bis(triphenylphosphine)), ((acetonitrile) palladium (II) tris(triphenylphosphine)) or (bis(acetonitrile)palladium(II) 1,3-bis (diphenylphosphino)propane).
    Type: Grant
    Filed: May 15, 1995
    Date of Patent: October 15, 1996
    Assignee: The Dow Chemical Company
    Inventors: John G. Hefner, Brian W. S. Kolthammer
  • Patent number: 5554777
    Abstract: Novel catalyst compositions comprising a cationic transition metal complex containing palladium, a mono-, di-, or tridendate ligand, and an anion are disclosed. The novel catalyst compositions can be used in a process for polymerizing carbon monoxide and at least one ethylenically unsaturated hydrocarbon to produce linear alternating polymers. Processes for preparing the novel catalyst compositions are also disclosed.
    Type: Grant
    Filed: July 8, 1994
    Date of Patent: September 10, 1996
    Assignee: The Dow Chemical Compamy
    Inventors: John G. Hefner, Brian W. S. Kolthammer
  • Patent number: 5312938
    Abstract: Olefins are polymerized in the presence of a homogeneous catalyst represented by the formula LTi(NR.sub.2).sub.3 wherein L is a .sub.II -bonded ligand selected from the group consisting of indenyl, C.sub.1 -C.sub.4 alkyl substituted indenyl, --OSiR.sub.3 substituted indenyl, R is a C.sub.1 -C.sub.4 alkyl group wherein each R attached to the same nitrogen atom is the same, but the R groups attached to different nitrogen atoms can be the same or different from those attached to the other nitrogen atoms.
    Type: Grant
    Filed: April 2, 1993
    Date of Patent: May 17, 1994
    Assignee: The Dow Chemical Company
    Inventors: John G. Hefner, Brian W. S. Kolthammer
  • Patent number: 5196490
    Abstract: Syndiotactic polymers of vinyl aromatic monomers are prepared by conducting the polymerization in the presence of a catalytic amount of the reaction product of polymethylaluminoxane and a cyclopentadienyl/titanium complex.
    Type: Grant
    Filed: June 6, 1991
    Date of Patent: March 23, 1993
    Assignee: The Dow Chemical Company
    Inventors: Richard E. Campbell, Jr., John G. Hefner
  • Patent number: 5194532
    Abstract: Olefins are polymerized in the presence of a homogeneous catalyst represented by the formula LTi(NR.sub.2).sub.3 wherein L is a .pi.-bonded ligand selected from the group consisting of indenyl, C.sub.1 -C.sub.4 alkyl substituted indenyl, --OSiR.sub.3 substituted indenyl, R is a C.sub.1 -C.sub.4 alkyl group wherein each R attached to the same nitrogen atom is the same, but the R groups attached to different nitrogen atoms can be the same or different from those attached to the other nitrogen atoms.
    Type: Grant
    Filed: June 12, 1992
    Date of Patent: March 16, 1993
    Assignee: The Dow Chemical Company
    Inventors: John G. Hefner, Brian W. S. Kolthammer, Dennis R. Gifford
  • Patent number: 5045517
    Abstract: Syndiotactic polymers of vinyl aromatic monomers are prepared by conducting the polymerization in the presence of a catalytic amount of the reaction product of polymethylaluminoxane and a cyclopentadienyl/titanium complex.
    Type: Grant
    Filed: January 5, 1990
    Date of Patent: September 3, 1991
    Assignee: The Dow Chemical Company
    Inventors: Richard E. Campbell, Jr., John G. Hefner
  • Patent number: 4956323
    Abstract: Ziegler-Natta catalysts for polymerizing .alpha.-olefins are prepared by the addition of tetrakis(dialkylaminde or diarylamide) derivatives of titanium, and a metal-containing reducing agent such as ethyl aluminum dichloride to a suitable support material such as magnesium chloride. Olefins are polymerized in the presence of these supported catalysts and an aluminum containing cocatalyst or activator such as triethylaluminum.
    Type: Grant
    Filed: September 8, 1989
    Date of Patent: September 11, 1990
    Assignee: The Dow Chemical Company
    Inventor: John G. Hefner
  • Patent number: 4892914
    Abstract: Ziegler-Natta catalysts for polymerizing .alpha.-olefins are prepared by the addition of tetrakis(dialkylamide or diarylamide) derivatives of titanium, and a metal-containing reducing agent such as ethyl aluminum dichloride to a suitable support material such as magnesium chloride. Olefins are polymerized in the presence of these supported catalysts and an aluminum containing cocatalyst or activator such as triethylaluminum.
    Type: Grant
    Filed: January 11, 1989
    Date of Patent: January 9, 1990
    Assignee: The Dow Chemical Company
    Inventor: John G. Hefner