Patents by Inventor Lawrence C. Mitchell

Lawrence C. Mitchell 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).

  • Process for preparing polycarbonates using substituted pyridine catalysts
    Patent number: 4286085
    Abstract: An interfacial polymerization process for preparing a high molecular weight aromatic carbonate polymer by reacting a dihydric phenol with a carbonate precursor in the presence of a catalytic amount of a substituted pyridine or a salt of a substituted pyridine.
    Type: Grant
    Filed: December 28, 1979
    Date of Patent: August 25, 1981
    Assignee: General Electric Company
    Inventors: Donald B. G. Jaquiss, Victor Mark, Lawrence C. Mitchell
  • Process for producing bisphenols
    Patent number: 4201878
    Abstract: Bisphenols substantially free of by-products, are produced rapidly by reacting a phenol and a compound of the formulae: ##STR1## wherein R and R' are hydrogen, lower alkyl or aryl; X is lower alkoxy or the same as X'; Y is chlorine or the same as X; X' is aryloxy; Z is a 1,2- or 1,3-propylenedioxy (that may optionally carry hydroxy, lower alkyl or lower hydroxyalkyl substituents), or arylenedioxy radical; n is integer from three to nine; m is (n-1).
    Type: Grant
    Filed: February 10, 1978
    Date of Patent: May 6, 1980
    Assignee: General Electric Company
    Inventors: Victor Mark, Lawrence C. Mitchell, Charles V. Hedges
  • Process for preparing 2,2-bis(4-hydroxy-phenyl) propane from distillation by-products thereof
    Patent number: 4192954
    Abstract: A process is disclosed for the production of 2,2-bis(4-hydroxyphenyl) propane, herein referred to as bisphenol-A, from by-products remaining after purification distillation of bisphenol-A produced from a condensation reaction of phenol and acetone. The process comprises mixing the by-products with phenol and adding anhydrous hydrogen chloride under superatmospheric pressure to the resulting mixture to isomerize those by-products isomerizable to bisphenol-A for subsequent recovery.
    Type: Grant
    Filed: December 23, 1977
    Date of Patent: March 11, 1980
    Assignee: General Electric Company
    Inventors: Henry P. Barker, Lawrence C. Mitchell
  • Process for preparing 2,2-bis(4-hydroxy-phenyl) propane from distillation by-products thereof
    Patent number: 4188496
    Abstract: A process is disclosed for the production of 2,2-bis(4-hydroxyphenyl) propane, herein referred to as bisphenol-A, from by-products remaining after purification distillation of bisphenol-A produced from a condensation reaction of phenol and acetone. The process comprises mixing the by-products with phenol and treating the resulting mixture with anhydrous hydrogen bromide to isomerize those by-products isomerizable to bisphenol-A for subsequent recovery.
    Type: Grant
    Filed: December 23, 1977
    Date of Patent: February 12, 1980
    Assignee: General Electric Company
    Inventors: Donald B. G. Jaquiss, Lawrence C. Mitchell
  • Process for recovering 2,2-bis(4-hydroxyphenyl)propane from distillation residues from the preparation thereof
    Patent number: 4180683
    Abstract: A process is disclosed for the recovery of 2,2-bis(4-hydroxyphenyl)propane, herein referred to as bisphenol-A, from residues remaining after purification distillation of bisphenol-A produced from a condensation reaction of phenol and acetone. The process comprises mixing the residues with phenol in the absence of acidic reagents to precipitate a bisphenol-A-phenol crystalline adduct and recovering bisphenol-A from the separated adduct.
    Type: Grant
    Filed: December 23, 1977
    Date of Patent: December 25, 1979
    Assignee: General Electric Company
    Inventor: Lawrence C. Mitchell
  • .alpha.,.alpha.'-Bis(2-hydroxyethoxy)-2,3,5,6-tetrabromo-p-xylene
    Patent number: 4171456
    Abstract: The title compound can be made by reacting ethylene glycol with hexabromo-p-xylene in the presence of anhydrous potassium carbonate. The compound is useful as a fire retardant for plastics, and can be used to form a polyester of the linear type. Fibers made from such polyesters are useful for making fire retardant textiles, carpets, drapes, and garments.
    Type: Grant
    Filed: October 3, 1977
    Date of Patent: October 16, 1979
    Assignee: Ethyl Corporation
    Inventors: David R. Brackenridge, Lawrence C. Mitchell
  • Polycarbonate compositions
    Patent number: 4146524
    Abstract: Novel thermoplastic molding compositions are disclosed which comprise a polycarbonate and a halocarbon oil, wax or grease.
    Type: Grant
    Filed: December 2, 1977
    Date of Patent: March 27, 1979
    Assignee: General Electric Company
    Inventors: Lawrence C. Mitchell, Steven W. Scott