Patents Represented by Attorney Charles E. Krukiel

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  • High yield recycle process for lactide
    Patent number: 5136057
    Abstract: Processes are described for recovering lactic acid from impure lactide and the residue produced in the depolymerization of polylactic acid to lactide. Lactic acid is recovered from the impure lactide by a dual solvent extraction process and, from the polylactic acid residue by hydrolysis. The lactic acid recovered from the impure lactide and the depolymerization residue is recycled to provide for a high yield lactide process.
    Type: Grant
    Filed: October 22, 1991
    Date of Patent: August 4, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Kamlesh K. Bhatia
  • Degradable foam materials
    Patent number: 5134171
    Abstract: Closed cell rigid polyhydroxy acid resin compositions foamed with environmentally benign, which compositions are degradable and cause minimal environmental impact when discarded.
    Type: Grant
    Filed: January 27, 1992
    Date of Patent: July 28, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Howard S. Hammel, Robert O. York
  • Method for reducing the pore size of sintered metal filters by application of an alcoholic solution of a metal alkoxide which is converted to an insoluble hydrous metal oxide
    Patent number: 5130166
    Abstract: The invention is a process for modifying pore size near the surface of porous materials. The surface is contacted with an alcohol solution of a metal alkoxide which forms a hydrous oxide insoluble in water, an amount of water insufficient to hydrolyze fully the metal alkoxide, and a mineral acid for a time sufficient for the solution to penetrate the surface region but not the bulk. This is followed by exposing to sufficient moisture to complete hydrolysis and then curing to stabilize the metal oxide in the pores near the surface.
    Type: Grant
    Filed: December 14, 1990
    Date of Patent: July 14, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Harold G. Spencer
  • Multi-stage process with adiabatic reactors for preparing alkyl glyoxylates
    Patent number: 5126478
    Abstract: The process in which alkyl glyoxylates are prepared by the catalytic oxidative dehydrogenation of the corresponding alkyl glycolates is improved by carrying out the process in at least two adiabatic reaction stages in series, in which no more than about 60 percent of the stoichiometric amount of oxygen is used in the first stage.
    Type: Grant
    Filed: October 4, 1989
    Date of Patent: June 30, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: George E. Heinsohn
  • Solvent scrubbing recovery of lactide and other dimeric cyclic esters
    Patent number: 5117008
    Abstract: An improved process for the recovery of lactide or other dimeric cyclic ester from a gas stream containing the cyclic ester and such hydroxylic impurities as water and open-chain hydroxycarboxylic acids by scrubbing the gas stream with a nonpolar water-immiscible solvent at a temperature at which the cyclic ester is removed from the solvent and any water present in the gas stream is vaporized from the solvent. The cyclic ester is recovered from the solvent in a high state of optical purity.
    Type: Grant
    Filed: October 23, 1990
    Date of Patent: May 26, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Kamlesh K. Bhatia, Neville E. Drysdale, John R. Kosak
  • Management of waste solution containing photoresist materials
    Patent number: 5112491
    Abstract: The present invention relates to management of photoresist-resin-containing waste solution by feeding non-aged waste to a membrane device having a Desal-5 piperazine-based membrane modified to increase MWCO for uncharged organic molecules sufficiently so that, on a weight basis, alkalizing agent passage is greater than 90%, photoresist material rejection is essentially complete, color rejection is greater than 95% and COD rejection is greater than 80% to produce a clean permeate solution that can be recycled and a concentrate to be removed.
    Type: Grant
    Filed: March 1, 1991
    Date of Patent: May 12, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: John W. Strantz, Jr.
  • Biodegradable compositions for controlled release of chemical agents
    Patent number: 5110868
    Abstract: Solid compositions comprising water degradable oligomers of hydroxyacetic acid and lactic acid having molecular weights of 800-4000 and containing 40-60 mole percent hydroxyacetic acid. The compositions are useful as controlled release agents for chemicals, especially as a toilet bowl cleaning component. Optional ingredients include dyes, fragrances, filler materials, surfactants, algicides, pest control agents, quaternary ammonium salts, and mixtures thereof.
    Type: Grant
    Filed: January 14, 1991
    Date of Patent: May 5, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Harold E. Bellis, Virginia M. Osterman
  • Dehydrogenation of diols
    Patent number: 5110954
    Abstract: A process is provided for the production of lactones by the catalytic dehydrogenation of aliphatic diols containing from 3-7 carbon atoms and optionally one or more ether linkages in the diol chain. The reaction is conducted in the liquid phase with a copper chromite catalyst at a temperature of from about 150.degree.-250.degree. C. in the absence of added hydrogen, and preferably at reaction conditions where yields are about 99%.
    Type: Grant
    Filed: July 11, 1990
    Date of Patent: May 5, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Harold E. Bellis
  • Catalyst pack for ammonia conversion to HCN
    Patent number: 5096687
    Abstract: The manufacture of hydrogen cyanide by the catalytic reaction of air, ammonia and a hydrocarbon gas employing a catalyst pack which consists of a top layer of platinum-rhodium alloy catalyst gauze or granular catalyst and a bottom layer of platinum-rhodium alloy metal catalyst gauze or granular catalyst, wherein the top layer is a finer mesh than the bottom layer.
    Type: Grant
    Filed: October 9, 1990
    Date of Patent: March 17, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Jitendra P. Agrawal
  • Base-catalyzed dehydration of substituted cis-1,2-dihydroxycyclohexa-3,5-dienes
    Patent number: 5093514
    Abstract: A process for dehydrating compounds of the formula ##STR1## where --R is --CH.dbd.CH.sub.2, --C.tbd.CH --C.tbd.N or ##STR2## in an aqueous solution thereof is disclosed. In the case where R is --CH.dbd.CH.sub.2 or --C.dbd.CH, the temperature is preferably at least 50.degree. C. and preferably 75.degree. to 100.degree. C. The base is at least 0.1N and preferably 1.0 to 8N. Preferred bases are NaOH, KOH and C.sub.5 OH. In the case where --R is C.tbd.N, the temperature preferably is 20.degree. to 50.degree. C.
    Type: Grant
    Filed: December 7, 1990
    Date of Patent: March 3, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Alan D. Grund, Ronald J. Huss, Michael H. Reimer
  • Process for rapid conversion of oligomers to cyclic esters
    Patent number: 5091544
    Abstract: A gas-assisted process for the rapid conversion of oligomers of alpha-hydroxycarboxylic acids, esters or nitrogen salts thereof to cyclic esters in high yields and high states of purity. An inert gas is intimately contacted with the oligomer so as to create a large interfacial area. The large interfacial area permits removal of the cyclic ester substantially as fast as the cyclic ester is formed.
    Type: Grant
    Filed: September 21, 1990
    Date of Patent: February 25, 1992
    Assignee: E. I. du Pont de Nemours and Company
    Inventor: Kamlesh K. Bhatia
  • Electronics protective packaging film
    Patent number: 5091229
    Abstract: Packages prepared from a flexible static charge-dissipating structure comprising a substrate film, a coating layer of heat sealable thermoplastic matrix containing micron sized particles of a silica containing material surface coated with antimony-containing tin oxide crystallites, and optionally a thin layer of metal, provide excellent static charge protection to sensitive electronic components.
    Type: Grant
    Filed: August 14, 1990
    Date of Patent: February 25, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Ralph C. Golike, Hua-Feng Huang, Herminio C. Llevat
  • Process for preparing cyclic esters using a fluorocarbon
    Patent number: 5089632
    Abstract: Process for preparing high purity solvent-free cyclic esters from alpha hydroxycarboxylic acids via an intermediate oligomer wherein a fluorocarbon or a mixture of fluorocarbons is employed to strip the ester from the oligomer as well as a refrigerant to quench lactide from a gaseous reaction stream comprising, besides cyclic ester, unconverted alpha-hydroxycarboxylic acid and water.
    Type: Grant
    Filed: January 30, 1991
    Date of Patent: February 18, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Donald C. Paul
  • Low flammability cap-sensitive flexible explosive composition
    Patent number: 5080735
    Abstract: A cap-sensitive flexible explosive composition of reduced flammability is provided by incorporating a finely divided, cap-sensitive explosive in a flame resistant polymeric binder system which contains a compatible flame retardant material.
    Type: Grant
    Filed: March 23, 1990
    Date of Patent: January 14, 1992
    Assignee: E. I. du Pont de Nemours and Company
    Inventor: Martin G. Wagner
  • Polyhydroxy acid films
    Patent number: 5076983
    Abstract: The present invention relates to a process for producing degradable, shrinkable films of polyhydroxy acid and plasticizers including melt processing the materials to obtain uniform composition, forming the composition into a film, and biaxially orienting the film. Also, non-shrinkable films are produced by heat-setting the biaxially oriented films at temperature above the composition glass transition temperature and below its melt temperature while maintaining the film under restraint. Films thus produced are useful for disposable, environmentally benign packaging and other conventional film uses.
    Type: Grant
    Filed: July 16, 1990
    Date of Patent: December 31, 1991
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Gary L. Loomis, George J. Ostapchenko
  • Electroconductive particles and method for adjusting the isoelectric point thereof
    Patent number: 5071676
    Abstract: An electroconductive powder composition of antimony-containing tin oxide with an outer layer of hydrous metal oxide having an isoelectric point in the range from about 5 to 9.
    Type: Grant
    Filed: June 28, 1990
    Date of Patent: December 10, 1991
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Howard W. Jacobson
  • Process for preparing benzenesulfonate salts
    Patent number: 5069828
    Abstract: An improved process for preparing benzenesulfonate salts, such as 4-nonanoyloxybenzenesulfonic acid, sodium salt, from an appropriately substituted acid chloride or chloroformate and a hydroxybenzenesulfonic acid in which the reaction is conducted in the presence of a phase transfer catalyst selected from quaternary ammonium and quaternary phosphonium salts.
    Type: Grant
    Filed: June 6, 1989
    Date of Patent: December 3, 1991
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Donald J. Dumas, Vinayakam Subramanyam
  • Filtration device having hardened gum formed-in-place membranes
    Patent number: 5043069
    Abstract: Stable formed-in-place saccharinic gum membranes on a porous support, the membranes being modified by contact with at least an equivalent of multivalent cations to anionic groups in the gum.
    Type: Grant
    Filed: October 18, 1989
    Date of Patent: August 27, 1991
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Steven C. Brandon, Harold G. Spencer
  • One-step continuous process for preparing cyclic esters
    Patent number: 5043458
    Abstract: A continuous, gas-assisted atmospheric process for preparing cyclic esters of alpha-hydroxycarboxylic acids, such as lactide, which comprises feeding the reactants into a reactor having means for introducing an inert gas at the operating temperature, forming a reaction mass having cyclic esters in the reactor, passing a flow of said inert gas through said reactor whereby cyclic esters are swept from the reaction mass into a gaseous product stream, and recovering the cyclic esters therefrom.
    Type: Grant
    Filed: May 3, 1990
    Date of Patent: August 27, 1991
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Kamlesh K. Bhatia
  • Silica particulate composition
    Patent number: 5024826
    Abstract: A silica powder composition in which the individual powder particles comprise shaped hollow shells of amorphous hydroxylated silica having a shell thickness of from 10 to 50 nanometers.
    Type: Grant
    Filed: March 5, 1990
    Date of Patent: June 18, 1991
    Assignee: E. I. du Pont de Nemours and Company
    Inventor: Howard R. Linton