Patents Represented by Attorney P. S. Kalyanaraman
  • Patent number: 5994560
    Abstract: Described herein is a novel process to resolve a racemic compound into its optically active isomers without need for chemical transformation such as salt formation. The process advantageously utilizes polymers containing chiral moieties in their repeat units as well as exhibiting critical solution temperature behavior in a suitable solvent. An embodiment describes the resolution of tryptophan.
    Type: Grant
    Filed: August 29, 1996
    Date of Patent: November 30, 1999
    Assignee: Hoechst Celanese Corp.
    Inventors: Hyun Nam Yoon, Mengshi Lu, Naoya Ogata
  • Patent number: 5843609
    Abstract: This invention provides a free-flowing polyester dye microspheric powder which has superior stability and transparency for application in electrophotographic imaging systems. In another embodiment this invention provides a non-aqueous dispersion polymerization process for producing the invention polyester dye microspheric powder. A present invention toner composition comprises polyester dye microspheric powder, and one or more optional ingredients such as a charge control agent or a surfactant.
    Type: Grant
    Filed: September 3, 1997
    Date of Patent: December 1, 1998
    Assignee: Hoechst Celanese Corp.
    Inventors: Marie Borzo, Kophu Chiang, Eui-Won Choe, Rao D. Mikkilineni, Hyun-Nam Yoon
  • Patent number: 5814711
    Abstract: This invention discloses a novel process to prepare multi-block copolymers with high molecular weights from two immiscible polymer segments. In one embodiment, the two polymer segments are reacted in a solvent mixture which comprises N-methyl-2-pyrrolidinone and diglyme. Such polymers are useful for alignment layer applications in display devices.
    Type: Grant
    Filed: December 5, 1996
    Date of Patent: September 29, 1998
    Assignee: Hoechst Celanese Corp.
    Inventors: Eui Won Choe, Masayuki Arai, Marie Borzo
  • Patent number: 5772949
    Abstract: A thermally expandable wax composition and its use in polymer-based actuators is disclosed and claimed. The compositions are wax-based and include conductive filler as well as a viscosity modifier to stabilize the composition against segregation. Optionally included are thermoxidative stabilizers.
    Type: Grant
    Filed: August 7, 1997
    Date of Patent: June 30, 1998
    Assignee: Hoechst Celanese Corp.
    Inventors: M. Ishaq Haider, James E. Kuder, Barbara J. Long, Joseph D. Menczel, James B. Stamatoff, Michael Bayer
  • Patent number: 5744204
    Abstract: This invention discloses laminates comprising a liquid crystal polymer film inside and non-adherent, non-liquid crystalline polymer film on the outside, prepared by a process of coextrusion. Delamination of the outside layers yields a liquid crystal polymer film of superior surface quality. The invention is particularly suitable for preparing liquid crystal polymer-based polarizers with improved surface quality.
    Type: Grant
    Filed: December 5, 1996
    Date of Patent: April 28, 1998
    Assignee: Hoechst Celanese Corp.
    Inventor: Randy Douglas Jester
  • Patent number: 5738803
    Abstract: This invention provides novel liquid crystalline polymers which, when mixed with a suitable dye and extruded, yields polarizer films with superior polarizing efficiency, transmittance, dichroic ratio, and thermal and humidity stability. The invention further provides a process to prepare such polymers and polarizer films therefrom.
    Type: Grant
    Filed: December 14, 1995
    Date of Patent: April 14, 1998
    Assignee: Hoechst Celanese Corp
    Inventors: James P. Shepherd, Sunny S. Shen, Brian B. Marr, Larry F. Charbonneau
  • Patent number: 5525699
    Abstract: A copolymer consisting essentially of a repeating sequence represented by the formula ##STR1## where Ar.sub.1, Ar.sub.2, and Ar.sub.3, are each independently chosen from the group consisting of ##STR2## which are either unsubstituted or are substituted with one or more substituents chosen from the group consisting of alkyl groups having 1-6 carbon atoms, halogen (F, Cl or Br), and phenyl; Z, Y.sub.1 and Y.sub.2 are each independently O, NH, or S; n and m are positive integers; and X is a covalent bond, O, S, SO.sub.2, CO, C(C.sub.6 H.sub.5).sub.2, C(C.sub.6 H.sub.5)H, C(C.sub.6 H.sub.5)(CH.sub.3), C(CH.sub.3).sub.2, C(CH.sub.3)H, CH.sub.2, C(CF.sub.3).sub.2, or 3,3,5-trimethyl cyclohexyl. The polymers of this invention are derived from a minimum of three different monomers.
    Type: Grant
    Filed: May 15, 1992
    Date of Patent: June 11, 1996
    Assignee: Hoechst Celanese Corp.
    Inventors: Eui W. Choe, Marie Borzo
  • Patent number: 5443783
    Abstract: Disclosed is a process for blow molding articles from liquid crystal polymers containing ionic moieties in the backbone. The ionic moieties increase the melt viscosity of the polymers sufficiently high to blow mold articles therefrom. An illustrative liquid crystal polymer is made from 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and sodium 5-sulfoisophthalate.
    Type: Grant
    Filed: March 23, 1993
    Date of Patent: August 22, 1995
    Assignee: Hoechst Celanese Corp.
    Inventors: James P. Shepherd, Linda C. Sawyer, Gerald Farrow
  • Patent number: 5344980
    Abstract: Novel 4-substituted acetophenone anils and methods for preparing 1,3,5-tris(4'-hydroxyphenyl)benzenes from 4-substituted acetophenones such as 4-hydroxyacetophenones or, from substituted 4-hydroxyacetophenone-anils such as 4-hydroxyacetophenone-anil by reacting the 4-substituted acetophenone or corresponding anil with an aniline derivative.
    Type: Grant
    Filed: November 23, 1993
    Date of Patent: September 6, 1994
    Assignee: Hoechst Celanese Corp.
    Inventors: Mohammad Aslam, William Basinger
  • Patent number: 5326661
    Abstract: This invention provides novel polymers which contain discrete photoconductive and electrooptic moieties. The moieties may exist as part of the main chain of the polymer or as pendant side chains. The polymers have utility as transparent photorefractive media in photorefractive devices.
    Type: Grant
    Filed: November 13, 1991
    Date of Patent: July 5, 1994
    Assignee: Hoechst Celanese Corp.
    Inventors: Michael Sansone, Harris A. Goldberg, James L. McGinnis, Karsten Blatter, Ching F. Shu, Anthony East
  • Patent number: 5302737
    Abstract: This invention provides a process to regioselectively silylcarbonylate 1-alkynes and in predominantly the Z-isomer with substantial absence of hydrosilylation by-products. The process involves reacting a 1-alkyne with an organosilane and carbon monoxide in a solvent in the presence of a catalyst. The catalyst is a carboxylate salt of a metal such as rhodium, iridium or rhenium.
    Type: Grant
    Filed: December 23, 1992
    Date of Patent: April 12, 1994
    Assignee: Trinity University
    Inventors: Michael P. Doyle, Michael S. Shanklin
  • Patent number: 5300698
    Abstract: Novel 4-substituted acetophenone anils and methods for preparing 1,3,5-tris(4'-hydroxyphenyl)benzenes from 4-substituted acetophenones such as 4-hydroxyacetophenones or, from substituted 4-hydroxyacetophenone-anils such as 4-hydroxyacetophenone-anil by reacting the 4-substituted acetophenone or corresponding anil with an aniline derivative.
    Type: Grant
    Filed: May 27, 1993
    Date of Patent: April 5, 1994
    Assignee: Hoechst Celanese Corporation
    Inventors: Mohammad Aslam, William Basinger
  • Patent number: 5247042
    Abstract: This invention provides novel side chain polymers which exhibit nonlinear optical response, and which have utility as a transparent optical component in all-optical and electrooptical light switch and light modulator devices.
    Type: Grant
    Filed: September 11, 1989
    Date of Patent: September 21, 1993
    Assignee: Hoechst Celanese Corp.
    Inventors: Diane E. Allen, Ronald N. DeMartino, Hyun-Nam Yoon
  • Patent number: 5232757
    Abstract: This invention provides a superior process for optical information storage by providing a mixture of azaannulene compounds in the recording layer. The recording layer exhibits large positive contrast in the recorded areas upon recording with laser radiation. The positive contrast is surprisingly larger than the positive contrasts exhibited by recording layers made from the individual azaannulenes included in the mixture, and because of this large positive contrast the sensitivity of the medium is high and consequently low laser powers are sufficient to effect the recording.
    Type: Grant
    Filed: December 6, 1991
    Date of Patent: August 3, 1993
    Assignee: Hoechst Celanese Corp.
    Inventors: Palaiyur S. Kalyanaraman, Harris A. Goldberg, Rachel S. Kohn
  • Patent number: 5223640
    Abstract: This invention provides a process to prepare optically active .alpha.-aryl propionic acids without the need for resolving a racemic mixture. In one embodiment of the process, an acetophenone is sequentially converted to a 1-alkyne, then to an .alpha.-aryl .beta.-silylated acrolein, and then to an acrylic acid, which is then asymmetrically hydrogenated to an optically active .alpha.-aryl propionic acid.
    Type: Grant
    Filed: December 23, 1992
    Date of Patent: June 29, 1993
    Assignee: Hoechst Celanese Corporation
    Inventors: Ahmed M. Tafesh, Sambasivarao Kotha, Kenneth G. Davenport
  • Patent number: 5220067
    Abstract: This invention provides a process for directly preparing hydrohalide salts of arylethylamines from (.alpha.-chloro-.alpha.-oximino)acetophenones. The process involves hydrogenation in presence of a transition metal catalyst in an organic acid in substantial absence of moisture. The process is illustrated by conversion of 4-hydroxy (.alpha.-chloro-.alpha.
    Type: Grant
    Filed: March 30, 1992
    Date of Patent: June 15, 1993
    Assignee: Hoechst Celanese Corporation
    Inventors: Ahmed Tafesh, B. Frank Wood, Joseph A. McDonough, Graham N. Mott
  • Patent number: 5212250
    Abstract: In one embodiment this invention provides poly(maleic anhydride) side chain copolymers which exhibit nonlinear optical susceptibility and which can be formed into crack-free thin film waveguiding media. An invention copolymer is illustrated by the recurring structure: ##STR1## The side chain chromophores can be oriented by an external field to form a noncentrosymmetric thin film which exhibits second order nonlinear optical susceptibility.
    Type: Grant
    Filed: September 17, 1991
    Date of Patent: May 18, 1993
    Assignee: Hoechst Celanese Corp.
    Inventors: Iain McCulloch, Thomas M. Leslie
  • Patent number: 5210165
    Abstract: This invention provides novel polymers containing alkyl vinylidene cyanide moieties that exhibit nonlinear optical and piezoelectric properties. The polymers have utility as media in optical devices.
    Type: Grant
    Filed: June 21, 1991
    Date of Patent: May 11, 1993
    Assignee: Hoechst Celanese Corp.
    Inventors: Henry K. Hall, Jr., Tun F. Way
  • Patent number: 5192621
    Abstract: This invention provides novel polymers that contain, in their side chains, 4-benzoyloxyphenyl moieties. These polymers have utility as coating to protect polyester materials from damage due to ultraviolet radiation.
    Type: Grant
    Filed: April 9, 1992
    Date of Patent: March 9, 1993
    Assignee: Hoechst Celanese Corp.
    Inventors: Gunilla E. Gillberg-Laforce, Josefina L. Pruksarnukul
  • Patent number: 5187234
    Abstract: This invention provides novel vinyl polymers with pendant side chains which exhibit nonlinear optical response. The polymers have utility as a transparent optical media in optical devices.
    Type: Grant
    Filed: September 6, 1991
    Date of Patent: February 16, 1993
    Assignee: Hoechst Celanese Corp.
    Inventors: Thomas M. Leslie, Ching F. Shu, Karsten Blatter, Ronald DeMartino, Frank Battito