Patents by Inventor Ravi B. Shankar

Ravi B. Shankar 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).

  • Publication number: 20020160907
    Abstract: A supported catalyst and methods for making and using the same, by employing organometallic Group 4-10 catalysts with specially selected dienes, which, when combined with a cocatalyst, result in a supported catalyst which has improved kinetic profiles in the gas polymerization process.
    Type: Application
    Filed: October 18, 2001
    Publication date: October 31, 2002
    Inventors: Edmund M. Carnahan, David R. Neithamer, Ravi B. Shankar
  • Publication number: 20020151662
    Abstract: Metal complexes comprising a polycyclic, fused ring ligand or inertly substituted derivative thereof comprising at least: (1) a cyclopentadienyl ring, (2) a 7 membered polyatomic ring, and (3) one or more aromatic ring systems, with the proviso that said 7 membered ring (2), is fused to both the cyclopentadienyl ring (1), and said one or more aromatic ring systems (3), and substituted in at least one ring position with a substituent group resulting in sp2 hybridization on the ring atom bonded thereto; polymerization catalysts; and olefin polymerization processes using the same are disclosed.
    Type: Application
    Filed: April 16, 2002
    Publication date: October 17, 2002
    Inventors: Richard E. Campbell, Jerzy Klosin, Ravi B. Shankar, Francis J. Timmers, Robert K. Rosen, Shaoguang Feng
  • Patent number: 6417405
    Abstract: Substituted or unsubstituted cyclopentadienyl are prepared by reducing 4-ketocyclopentene to an alcohol, replacing the hydroxyl functionality with a leaving group and deprotonating the resulting product under base induced elimination conditions.
    Type: Grant
    Filed: June 20, 2001
    Date of Patent: July 9, 2002
    Assignee: The Dow Chemical Company
    Inventor: Ravi B. Shankar
  • Publication number: 20020062011
    Abstract: Compounds and metal complexes comprising a polycyclic, fused ring ligand or inertly substituted derivative thereof having up to 60 atoms other than hydrogen, said ligand comprising at least: (1) a cyclopentadienyl ring, (2) a 6,7,or 8 membered ring other than a 6-carbon aromatic ring, and (3) an aromatic ring, with the proviso that said 6, 7, or 8 membered ring (2), is fused to both the cyclopentadienyl ring (1), and the aromatic ring (3), polymerization catalysts, a process to prepare the novel compounds and complexes, and olefin polymerization processes using the same are disclosed.
    Type: Application
    Filed: June 12, 2001
    Publication date: May 23, 2002
    Inventors: Richard E. Campbell,, Jerzy Klosin, Ravi B. Shankar, Francis J. Timmers, Robert K. Rosen
  • Publication number: 20020002308
    Abstract: A process for forming 4-ketocyclopentene and substituted 4-ketocyclopentene compounds starting from the corresponding 1-carbohydrocarbyloxy-2-keto-4-hydroxy-5-cyclopentene by reduction followed by decarboxylation using zinc dichloride or zinc dibromide. The ketone may thereafter be converted to a cyclopentadiene compound by reducing the ketone to form an alcohol, replacing the hydroxyl functionality of the alcohol under substitution conditions with a leaving group, and deprotonating the resulting product under base induced elimination conditions to form the cyclopentadiene compound. Alternatively functionalized cyclopentadienyl compounds can be produced without isolation of an unsubstituted cyclopentadienyl compound by combining the elimination and deprotonation steps with a replacement step in a single unit operation.
    Type: Application
    Filed: June 20, 2001
    Publication date: January 3, 2002
    Inventor: Ravi B. Shankar
  • Patent number: 6329486
    Abstract: Group 4 metal complexes comprising a cyclopentaphenanthreneyl ligand, catalytic derivatives thereof and their use as olefin polymerization catalysts, especially for the copolymerization of ethylene and a vinylaromatic monomer are disclosed. The resulting copolymers are uniform, pseudo-random copolymers of ethylene and a vinylaromatic monomer having a cluster index, CIES less than 1.0 and a polymerized vinylaromatic monomer content less than 50 mole percent.
    Type: Grant
    Filed: June 21, 2000
    Date of Patent: December 11, 2001
    Assignee: The Dow Chemical Company
    Inventors: Ravi B. Shankar, Francis J. Timmers, Daniel J. Arriola, Richard E. Campbell, Jr.
  • Patent number: 6323294
    Abstract: Group 4 metal complexes comprising a cyclopentaphenanthreneyl ligand, catalytic derivatives thereof and their use as olefin polymerization catalysts, especially for the copolymerization of ethylene and a vinylaromatic monomer are disclosed. The resulting copolymers are uniform, pseudo-random copolymers of ethylene and a vinylaromatic monomer having a cluster index, CIES less than 1.0 and a polymerized vinylaromatic monomer content less than 50 mole percent.
    Type: Grant
    Filed: June 21, 2000
    Date of Patent: November 27, 2001
    Assignee: The Dow Chemical Company
    Inventors: Richard E. Campbell, Jr., Ravi B. Shankar, Francis J. Timmers, Daniel J. Arriola
  • Patent number: 6310256
    Abstract: A process for forming 4-ketocyclopentene and substituted 4-ketocyclopentene compounds starting from the corresponding 1-carbohydrocarbyloxy-2-keto-4-hydroxy-5-cyclopentene by reduction followed by decarboxylation.
    Type: Grant
    Filed: November 19, 1999
    Date of Patent: October 30, 2001
    Assignee: The Dow Chemical Company
    Inventors: Ravi B. Shankar, Francis J. Timmers
  • Patent number: 6150297
    Abstract: Group 4 metal complexes comprising a cyclopentaphenanthreneyl ligand, catalytic derivatives thereof and their use as olefin polymerization catalysts, especially for the copolymerization of ethylene and a vinylaromatic monomer are disclosed. The resulting copolymers are uniform, pseudo-random copolymers of ethylene and a vinylaromatic monomer having a cluster index, CI.sub.ES less than 1.0 and a polymerized vinylaromatic monomer content less than 50 mole percent.
    Type: Grant
    Filed: July 27, 1998
    Date of Patent: November 21, 2000
    Assignee: The Dow Chemical Company
    Inventors: Richard E. Campbell, Jr., Francis J. Timmers, Ravi B. Shankar, Daniel J. Arriola
  • Patent number: 6034022
    Abstract: Group 4 metal constrained geometry complexes comprising a fused ring indenyl derivative ligand, catalytic derivatives thereof, processes for preparing the same and their use as components of olefin polymerization catalysts are disclosed.
    Type: Grant
    Filed: June 3, 1999
    Date of Patent: March 7, 2000
    Assignee: The Dow Chemical Company
    Inventors: Mark H. McAdon, Jasson T. Patton, Peter N. Nickias, Ravi B. Shankar, Francis J. Timmers, Brian W. S. Kolthammer, Daniel D. VanderLende, Steven M. Ueligger
  • Patent number: 5965756
    Abstract: Group 4 metal constrained geometry complexes comprising a fused ring indenyl derivative ligand, catalytic derivatives thereof, processes for preparing the same and their use as components of olefin polymerization catalysts are disclosed.
    Type: Grant
    Filed: October 14, 1997
    Date of Patent: October 12, 1999
    Assignee: The Dow Chemical Company
    Inventors: Mark H. McAdon, Jasson T. Patton, Peter N. Nickias, Ravi B. Shankar, Francis J. Timmers, Brian W. Kolthammer, Daniel D. VanderLende, Steven M. Ueligger
  • Patent number: 5885991
    Abstract: Disclosed are thiocyanomethyloxy(or thiocyanomethylthio)-1,2,3-benzatriazin-4(3H)-one compounds corresponding to one of the formulae: ##STR1## wherein Z represents oxygen or sulfur; X represents --C1, --F, --I, C.sub.1 -C.sub.7 straight or branched chain alkyl, C.sub.1 -C.sub.7 straight or branched chain alkoxy, --CF.sub.3, --OCF.sub.3, --CN, --COOR wherein R is C.sub.1 -C.sub.7 straight or branched chain alkyl and n is an integer of from 0-4.These compounds have been found to exhibit antimicrobial and marine antifouling activity in industrial and commercial applications and compositions containing these compounds are so employed.
    Type: Grant
    Filed: June 26, 1997
    Date of Patent: March 23, 1999
    Assignee: The Dow Chemical Company
    Inventors: Ravi B. Shankar, R. Garth Pews, Duane R. Romer
  • Patent number: 5723486
    Abstract: Disclosed are 1,3-dithiolo(4,5-d)-1,3-dithiino-2-thione compounds corresponding to one of the formulae: ##STR1## wherein R.sup.1 represents --Br, --Cl, --F, --CN or --CH(CH.sub.2).sub.n CH.sub.3 and n is an integer of from 0 to 10.These compounds as well as the unsubstituted compound have been found to exhibit antimicrobial and marine antifouling activity in industrial and commercial applications and compositions containing these compounds are so employed.
    Type: Grant
    Filed: July 10, 1996
    Date of Patent: March 3, 1998
    Assignee: The Dow Chemical Company
    Inventors: Weishi W. Wu, Duane R. Romer, Ravi B. Shankar, R. Garth Pews
  • Patent number: 5703114
    Abstract: Disclosed is the use of compositions employing a 4,5-dicyano-1,3-dithiole-2-one (or thione) compound corresponding to the formula: ##STR1## wherein Z is oxygen or sulfur as the active antimicrobial and marine antifouling agent.
    Type: Grant
    Filed: July 10, 1996
    Date of Patent: December 30, 1997
    Assignee: The Dow Chemical Company
    Inventors: Ravi B. Shankar, Duane R. Romer, R. Garth Pews
  • Patent number: 5703102
    Abstract: Disclosed are compositions containing 1,2,5-thiadiazolo-1,3-dithiole-2-one or thione corresponding to the formula: ##STR1## wherein Z is oxygen or sulfur and the use thereof as antimicrobial and marine antifouling agents.
    Type: Grant
    Filed: July 10, 1996
    Date of Patent: December 30, 1997
    Assignee: The Dow Chemical Company
    Inventors: Ravi B. Shankar, Duane R. Romer, R. Garth Pews
  • Patent number: 5661176
    Abstract: Disclosed are (2-one (or thione)-1,3-dithiole-4,5-diyl)bis(thiomethylthiocyanate) compounds corresponding to the formula: ##STR1## wherein Z is oxygen or sulfur, compositions containing said compounds and their use as antimicrobial and marine antifouling agents.
    Type: Grant
    Filed: July 10, 1996
    Date of Patent: August 26, 1997
    Assignee: The Dow Chemical Company
    Inventors: Duane R. Romer, Weishi W. Wu, Ravi B. Shankar, R. Garth Pews
  • Patent number: 5661165
    Abstract: Disclosed are ((4-phenyl-1,2,5--thiadiazol-3-yl)oxy)methyl ester thiocyanic acid compounds corresponding to the formula: ##STR1## wherein X represents --Br, --Cl, --F, --CF.sub.3, --OCF.sub.3, --CN, C.sub.1 -C.sub.7 straight or branched chain alkyl, C.sub.1 -C.sub.7 straight or branched chain alkoxy or --COOR wherein R is --H or C.sub.1 -C.sub.7 straight or branched chain alkyl and n is an integer of from 0-5.These compounds have been found to exhibit antimicrobial and marine antifouling activity in industrial and commercial applications and compositions containing these compounds are so employed.
    Type: Grant
    Filed: July 10, 1996
    Date of Patent: August 26, 1997
    Assignee: The Dow Chemical Company
    Inventors: Ravi B. Shankar, R. Garth Pews, Duane R. Romer
  • Patent number: 5633219
    Abstract: Various 5H-pyrrolo(3',4':5,6)(1,4) dithiino-(2,3-C)(1,2,5)thiadiazole-5,7(6H)-diones corresponding to the formula ##STR1## wherein R represents --H, benzyl, phenethyl, a C.sub.1 -C.sub.10 straight or branched chain alkyl radical, a C.sub.3 -C.sub.10 cycloalkyl radical, a C.sub.1 -C.sub.10 straight or branched chain alkoxy radical, a C.sub.3 -C.sub.10 -cycloalkoxy, an ester of the formula --CH.sub.2 CH.sub.2 O--C(O)--R.sup.1, wherein R.sup.1 represents a C.sub.1 -C.sub.6 straight or branched chain alkyl radical or a C.sub.3 -C.sub.6 cycloalkyl radical or R represents phenyl substituted with from 0-5 halo, C.sub.1 -C.sub.6 straight or branched chain alkyl, cyano, nitro groups, or an ester of the formula --OC(O)--R.sup.1, wherein R.sup.1 represents a C.sub.1 -C.sub.6 straight or branched chain alkyl radical or a C.sub.3 -C.sub.6 cycloalkyl radical or an amide of the formula --C(O)--N(R.sup.2).sub.x, wherein each R.sup.2 independently represents a C.sub.1 -C.sub.6 straight or branched chain alkyl radical or a C.
    Type: Grant
    Filed: July 10, 1996
    Date of Patent: May 27, 1997
    Assignee: The Dow Chemical Company
    Inventors: Ravi B. Shankar, R. Garth Pews, Duane R. Romer
  • Patent number: 5631277
    Abstract: Disclosed is (2-thione-1,3-dithiole 4,5-diyl) bis(thiocyanate), its preparation and its use as an antimicrobial and marine antifouling agent.
    Type: Grant
    Filed: July 10, 1996
    Date of Patent: May 20, 1997
    Assignee: The Dow Chemical Company
    Inventors: Duane R. Romer, Weishi W. Wu, Ravi B. Shankar, R. Garth Pews
  • Patent number: 5631207
    Abstract: Disclosed is the use of compositions employing 5-alkyl-1,3,4-oxadiazol(or thiadiazol)-2-thiomethylthiocyanates as the active marine antifouling agent.
    Type: Grant
    Filed: July 10, 1996
    Date of Patent: May 20, 1997
    Assignee: The Dow Chemical Company
    Inventors: Duane R. Romer, Ravi B. Shankar, R. Garth Pews