Patents by Inventor George W. Roberts
George W. Roberts 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).
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Patent number: 7410620Abstract: A method for carrying out the continuous polymerization of a monomer in a carbon dioxide reaction medium comprises the steps of: (a) providing an apparatus including a continuous reaction vessel and a separator; (b) carrying out a polymerization reaction in the reaction vessel by combining a monomer and a carbon dioxide reaction medium therein (and preferably by also combining an initiator therein), wherein the reaction medium is a liquid or supercritical fluid, and wherein the reaction produces a solid polymer product in the reaction vessel; then (c) withdrawing a continuous effluent stream from the reaction vessel during the polymerization reaction, wherein the effluent stream is maintained as a liquid or supercritical fluid; then (d) passing the continuous effluent stream through the separator and separating the solid polymer therefrom while maintaining at least a portion of the effluent stream as a liquid or supercritical fluid; and then (e) returning at least a portion of the continuous effluent stream tType: GrantFiled: April 22, 2005Date of Patent: August 12, 2008Assignee: North Carolina State UniversityInventors: Paul A. Charpentier, Joseph M. DeSimone, George W. Roberts
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Patent number: 7408009Abstract: A method of hydrogenating a polymer comprises: (a) providing a dense phase, the dense phase comprising a polymer in a solvent; (b) providing a catalyst system, the catalyst system comprising as least one metal hydrogenation catalyst (preferably including nickel or ruthenium); and (c) providing a light phase, the light phase comprising, consisting of or consisting essentially of hydrogen and carbon dioxide; and (d) contacting the dense phase, the light phase and the catalyst system under conditions in which the hydrogen reacts with the polymer and hydrogenates the polymer.Type: GrantFiled: November 3, 2003Date of Patent: August 5, 2008Assignee: North Carolina State UniversityInventors: George W. Roberts, Dawei Xu, Douglas J. Kiserow, Ruben G. Carbonell
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Patent number: 7063839Abstract: A method for continuously separating polymer from a high pressure fluid stream comprises subjecting the high pressure fluid stream comprising polymer particles to a filter, wherein the filter segregates the high pressure fluid stream from the polymer particles; subjecting the polymer particles to a rotating device which transports the polymer particles away from the filter, wherein the polymer particles are exposed to thermal conditions sufficient to melt the polymer particles and form a seal surrounding at least a portion of the rotating device; and separating the molten polymer from the rotating device. The method is carried out such that the separation of polymer from the high pressure fluid stream occurs under steady-state.Type: GrantFiled: October 18, 2004Date of Patent: June 20, 2006Assignee: North Carolina State UniversityInventors: Joseph R. Royer, George W. Roberts
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Patent number: 6919383Abstract: A method of depolymerizing a polymer comprises contacting a polymer with a fluid comprising carbon dioxide and at least one component, wherein the fluid plasticizes the polymer and facilitates penetration of the component into the polymer to depolymerize the polymer and form oligomeric units, monomeric units, or combinations thereof.Type: GrantFiled: April 10, 2002Date of Patent: July 19, 2005Assignee: North Carolina State UniversityInventors: Saad A. Khan, George W. Roberts, Joseph R. Royer
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Patent number: 6914105Abstract: A method for carrying out the continuous polymerization of a monomer in a carbon dioxide reaction medium comprises the steps of: (a) providing an apparatus including a continuous reaction vessel and a separator; (b) carrying out a polymerization reaction in the reaction vessel by combining a monomer and a carbon dioxide reaction medium therein (and preferably by also combining an initiator therein), wherein the reaction medium is a liquid or supercritical fluid, and wherein the reaction produces a solid polymer product in the reaction vessel; then (c) withdrawing a continuous effluent stream from the reaction vessel during the polymerization reaction, wherein the effluent stream is maintained as a liquid or supercritical fluid; then (d) passing the continuous effluent stream through the separator and separating the solid polymer therefrom while maintaining at least a portion of the effluent stream as a liquid or supercritical fluid; and then (e) returning at least a portion of the continuous effluent stream tType: GrantFiled: November 9, 2000Date of Patent: July 5, 2005Assignees: North Carolina State University, The University of North Carolina at Chapel HillInventors: Paul A. Charpentier, Joseph M. DeSimone, George W. Roberts
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Patent number: 6900267Abstract: Methods of carrying out a reactive extrusion processes are described that include combining at least one polymer, oligomer, or combination thereof, a carbon dioxide containing fluid, and at least one reactant in an extruder to form a mixture such that the carbon dioxide containing fluid comes into intimate contact with the at least one polymer, oligomer, or combination thereof and assists in a reaction between the at least one polymer, oligomer, or combination thereof and the at least one reactant, and wherein the at least one polymer, oligomer, or combination thereof is modified upon reaction with the at least one reactant.Type: GrantFiled: December 12, 2002Date of Patent: May 31, 2005Assignees: North Carolina State University, The University of North Carolina at Chapel HillInventors: Joseph Royer, Joseph M. DeSimone, George W. Roberts, Saad A. Khan
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Patent number: 6806332Abstract: A method for continuously separating polymer from a high pressure fluid stream comprises subjecting the high pressure fluid stream comprising polymer particles to a filter, wherein the filter segregates the high pressure fluid stream from the polymer particles; subjecting the polymer particles to a rotating device which transports the polymer particles away from the filter, wherein the polymer particles are exposed to thermal conditions sufficient to melt the polymer particles and form a seal surrounding at least a portion of the rotating device; and separating the molten polymer from the rotating device. The method is carried out such that the separation of polymer from the high pressure fluid stream occurs under steady-state.Type: GrantFiled: February 25, 2002Date of Patent: October 19, 2004Assignee: North Carolina State UniversityInventors: Joseph R. Royer, George W. Roberts
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Publication number: 20040162404Abstract: A method for forming a fluoropolymer comprises providing a reaction mixture comprising carbon dioxide, at least one fluoromonomer, and an initiator; and reacting the at least one fluoromonomer in the reaction mixture to form a fluoropolymer. The fluoropolymer has a multimodal molecular weight distribution.Type: ApplicationFiled: February 13, 2004Publication date: August 19, 2004Applicants: University of North Carolina at Chapel Hill, North Carolina State UniversityInventors: Joseph M. DeSimone, George W. Roberts, Paul A. Charpentier
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Patent number: 6716945Abstract: A method for forming a fluoropolymer comprises providing a reaction mixture comprising carbon dioxide, at least one fluoromonomer, and an initiator; and reacting the at least one fluoromonomer in the reaction mixture to form a fluoropolymer. The fluoropolymer has a multimodal molecular weight distribution.Type: GrantFiled: May 18, 2001Date of Patent: April 6, 2004Assignees: North Carolina State University, University of North Carolina at Chapel HillInventors: Joseph M. DeSimone, George W. Roberts, Paul A. Charpentier
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Publication number: 20030171495Abstract: Methods of carrying out a reactive extrusion processes are described that include combining at least one polymer, oligomer, or combination thereof, a carbon dioxide containing fluid, and at least one reactant in an extruder to form a mixture such that the carbon dioxide containing fluid comes into intimate contact with the at least one polymer, oligomer, or combination thereof and assists in a reaction between the at least one polymer, oligomer, or combination thereof and the at least one reactant, and wherein the at least one polymer, oligomer, or combination thereof is modified upon reaction with the at least one reactant.Type: ApplicationFiled: December 12, 2002Publication date: September 11, 2003Inventors: Joseph Royer, Joseph M. DeSimone, George W. Roberts, Saad A. Khan
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Publication number: 20030072690Abstract: A method for continuously separating polymer from a high pressure fluid stream comprises subjecting the high pressure fluid stream comprising polymer particles to a filter, wherein the filter segregates the high pressure fluid stream from the polymer particles; subjecting the polymer particles to a rotating device which transports the polymer particles away from the filter, wherein the polymer particles are exposed to thermal conditions sufficient to melt the polymer particles and form a seal surrounding at least a portion of the rotating device; and separating the molten polymer from the rotating device. The method is carried out such that the separation of polymer from the high pressure fluid stream occurs under steady-state.Type: ApplicationFiled: February 25, 2002Publication date: April 17, 2003Inventors: Joseph R. Royer, George W. Roberts
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Publication number: 20020169223Abstract: A method of depolymerizing a polymer comprises contacting a polymer with a fluid comprising carbon dioxide and at least one component, wherein the fluid plasticizes the polymer and facilitates penetration of the component into the polymer to depolymerize the polymer and form oligomeric units, monomeric units, or combinations thereof.Type: ApplicationFiled: April 10, 2002Publication date: November 14, 2002Inventors: Saad A. Khan, George W. Roberts, Joseph R. Royer
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Publication number: 20020040118Abstract: A method for forming a fluoropolymer comprises providing a reaction mixture comprising carbon dioxide, at least one fluoromonomer, and an initiator; and reacting the at least one fluoromonomer in the reaction mixture to form a fluoropolymer. The fluoropolymer has a multimodal molecular weight distribution.Type: ApplicationFiled: May 18, 2001Publication date: April 4, 2002Inventors: Joseph M. DeSimone, George W. Roberts, Paul A. Charpentier
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Patent number: 6217830Abstract: A method of separating a Fischer-Tropsch catalyst from the output slurry of a Fischer-Tropsch bubble column reactor, where the slurry comprises Fischer-Tropsch catalyst particles and liquid hydrocarbon product is disclosed. The method comprises contacting a compressed hydrocarbon solvent (e.g., a supercritical hydrocarbon solvent, or liquid hydrocarbon solvent which may be at near supercritical conditions) with the output slurry at a temperature and pressure where the liquid hydrocarbon product is soluble in the solvent to form a concentrated slurry phase containing the catalyst particles, and an enriched solvent phase containing liquid hydrocarbon product. This contacting step is then followed by the step of separating the concentrated slurry from the enriched solvent. Apparatus for carrying out the method of the invention is also disclosed.Type: GrantFiled: February 16, 2000Date of Patent: April 17, 2001Assignee: North Carolina State UniversityInventors: George W. Roberts, Peter K. Kilpatrick
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Patent number: 6114399Abstract: A method of separating a Fischer-Tropsch catalyst from the output slurry of a Fischer-Tropsch bubble column reactor, where the slurry comprises Fischer-Tropsch catalyst particles and liquid hydrocarbon product is disclosed. The method comprises contacting a compressed hydrocarbon solvent (e.g., a supercritical hydrocarbon solvent, or liquid hydrocarbon solvent which may be at near supercritical conditions) with the output slurry at a temperature and pressure where the liquid hydrocarbon product is soluble in the solvent to form a concentrated slurry phase containing the catalyst particles, and an enriched solvent phase containing liquid hydrocarbon product. This contacting step is then followed by the step of separating the concentrated slurry from the enriched solvent. Apparatus for carrying out the method of the invention is also disclosed.Type: GrantFiled: February 6, 1997Date of Patent: September 5, 2000Assignee: North Carolina State UniversityInventors: George W. Roberts, Peter K. Kilpatrick
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Patent number: 4859435Abstract: The present invention is directed to a process for removing minor amounts of oxygen from inert gas streams to result in very low levels of oxygen contamination in such inert gas streams, wherein the oxygen is removed by the action of stoichiometric quantities of methanol, which react with the oxygen over a catalyst at ambient feed temperature conditions without a requirement for external heating of the reaction.Type: GrantFiled: June 10, 1988Date of Patent: August 22, 1989Assignee: Air Products and Chemicals, Inc.Inventors: George W. Roberts, Shivaji Sircar, Paul Stepanoff
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Patent number: 4859434Abstract: The present invention is directed to a process for producing endothermic gases from methanol and inert gas streams containing minor amounts of oxygen, wherein the oxygen is reacted with stoichiometric excess quantities of methanol over a catalyst as ambient feed temperature conditions without a requirement for external heating of the reaction to produce an endothermic gas containing very low levels of oxygen and methanol and significant quantities of hydrogen, carbon monoxide, water and carbon dioxide.Type: GrantFiled: June 10, 1988Date of Patent: August 22, 1989Assignee: Air Products and Chemicals, Inc.Inventors: George W. Roberts, Shivaji Sircar, Paul Stepanoff
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Patent number: 4801574Abstract: The present invention relates to a method of activation of a CuO/ZnO/Al.sub.2 O.sub.3 catalyst slurried in a chemically inert liquid. Successful activation of the catalyst requires the use of a process in which the temperature of the system at any time is not allowed to exceed a certain critical value, which is a function of the specific hydrogen uptake of the catalyst at that same time. This process is especially critical for activating highly concentrated catalyst slurries, typically 25 to 50 wt %. Activation of slurries of CuO/ZnO/Al.sub.2 O.sub.3 catalyst is useful in carrying out the liquid phase methanol or the liquid phase shift reactions.Type: GrantFiled: December 2, 1987Date of Patent: January 31, 1989Assignee: Air Products and Chemicals, Inc.Inventors: Dennis M. Brown, Thomas H. Hsiung, Pradip Rao, George W. Roberts
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Patent number: 4766154Abstract: The present invention is a process for the production of methanol from a syngas feed containing carbon monoxide, carbon dioxide and hydrogen. Basically, the process is the combination of two liquid phase methanol reactors into a staging process, such that each reactor is operated to favor a particular reaction mechanism. In the first reactor, the operation is controlled to favor the hydrogenation of carbon monoxide, and in the second reactor, the operation is controlled so as to favor the hydrogenation of carbon dioxide. This staging process results in substantial increases in methanol yield.Type: GrantFiled: February 6, 1987Date of Patent: August 23, 1988Assignee: Air Products and Chemicals, Inc.Inventors: Leo W. Bonnell, Alan T. Perka, George W. Roberts
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Patent number: 4690215Abstract: Enhanced oil recovery from a crude oil reservoir is promoted following primary oil production, by subjecting the reservoir to water flooding, discontinuing the water flooding, preferably when the remaining oil is at an OIP level above 0.10, and then subjecting the reservoir to fireflooding with gas having an O.sub.2 content of at least 50%, preferably above 85%.Type: GrantFiled: May 16, 1986Date of Patent: September 1, 1987Assignee: Air Products and Chemicals, Inc.Inventors: George W. Roberts, James G. Hansel, Goutam H. Shahani