Patents by Inventor Christine Mendoza-Frohn
Christine Mendoza-Frohn 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: 7071283Abstract: The invention relates to a method for producing polycarbonate according to the method for the transesterification of molten mass whereby bis-(hydroxyaryl) compounds (bisphenols) and diaryl carbonates are reacted by means of reactive rectification.Type: GrantFiled: August 10, 2001Date of Patent: July 4, 2006Assignee: Bayer MaterialScience AGInventors: Gerald John, Edmund Dikow, Christine Mendoza-Frohn, Georg Ronge, Rolf Bachmann, Lutz Gottschalk, Michael Prein
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Publication number: 20040039151Abstract: The invention relates to a method for producing polycarbonate according to the method for the transesterification of molten mass whereby bis-(hydroxyaryl) compounds (bisphenols) and diaryl carbonates are reacted by means of reactive rectification.Type: ApplicationFiled: June 30, 2003Publication date: February 26, 2004Inventors: Gerald John, Edmund Dikow, Christine Mendoza-Frohn, Georg Ronge, Rolf Bachmann, Lutz Gottschalk, Michael Prein
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Patent number: 6649798Abstract: The present invention concerns a process for the production of methylenedianiline (MDA) having a high monomer content.Type: GrantFiled: August 7, 2002Date of Patent: November 18, 2003Assignee: Bayer AktiengesellschaftInventors: Stephan Klein, Dirk Grotjohann, Christine Mendoza-Frohn, Daniel Koch, Heinz-Herbert Müller, Hans-Georg Pirkl, Rudolf Uchdorf, Gerhard Wegener
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Publication number: 20030023116Abstract: The present invention concerns a process for the production of methylenedianiline (MDA) having a high monomer content.Type: ApplicationFiled: August 7, 2002Publication date: January 30, 2003Inventors: Stephan Klein, Dirk Grotjohann, Christine Mendoza-Frohn, Daniel Koch, Heinz-Herbert Mller, Hans-Georg Pirkl, Rudolf Uchdorf
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Patent number: 6458972Abstract: Macrocyclic ester compounds can be prepared from oligoesters by thermal cleavage in the presence of a thermostable benzene derivative.Type: GrantFiled: August 21, 2001Date of Patent: October 1, 2002Assignee: Haarmann & Reimer GmbHInventors: Horst Surburg, Dirk Müller, Stephan Klein, Christine Mendoza-Frohn, Georg Ronge, Kai Verkerk
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Publication number: 20020099163Abstract: A process for producing polycarbonate is disclosed. Accordingly a pre-reaction mixture containing a bis(hydroxyaryl) compound and a diaryl carbonate is formed and introduced through the top of a reactive rectification column under condition calculated to bring about a reaction. The resulting hydroxyaryl is eliminated and diaryl carbonate in vapor form is introduced at the bottom of the reactive rectification column.Type: ApplicationFiled: August 21, 2001Publication date: July 25, 2002Inventors: Gerald John, Edmund Dikow, Christine Mendoza-Frohn, Georg Ronge, Rolf Bachmann, Lutz Gottschalk, Michael Prein
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Publication number: 20020095045Abstract: Macrocyclic ester compounds can be prepared from oligoesters by thermal cleavage in the presence of a thermostable benzene derivative.Type: ApplicationFiled: August 21, 2001Publication date: July 18, 2002Inventors: Horst Surburg, Dirk Muller, Stephan Klein, Christine Mendoza-Frohn, Georg Ronge, Kai Verkerk
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Patent number: 6288284Abstract: The present invention relates to a process for the production of bis(4-hydroxyaryl)alkanes by an acid-catalyzed reaction between aromatic hydroxy compounds and ketones, in which the temperature, ketone content and water content of a liquid reaction mixture are adjusted by means of a suitably composed gas phase.Type: GrantFiled: July 3, 2000Date of Patent: September 11, 2001Assignee: Bayer AktiengesellschaftInventors: Rob Eek, Kaspar Hallenberger, Christine Mendoza-Frohn, Georg Ronge, Gerhard Fennhoff, Domien Sluyts, Werner Verhoeven
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Patent number: 5763717Abstract: A description is given of the preparation of hydroxybiphenyl by dehydrogenation of completely or partially hydrogenated precursors using a supported Rh catalyst which additionally contains chromium, manganese and alkali metal and can contain a sulphur compound. The Rh catalyst which can be used according to the invention is prepared from halide-free starting materials. The Rh catalyst is distinguished by a low dependence of the initial selectivity, with the selectivity in the run-in state and the running-in time on the conditions of the reductive pretreatment and requires only short running-in times to reach the optimum state.Type: GrantFiled: September 7, 1995Date of Patent: June 9, 1998Assignee: Bayer AktiengesellschaftInventors: Hans-Josef Buysch, Christine Mendoza-Frohn, Jurgen Scharschmidt, Ulrich Notheis, Rudolf Jurgen Klee, Gerhard Darsow
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Patent number: 5625097Abstract: The preparation of optionally substituted diphenylamine by reaction of optionally substituted aniline with optionally substituted cyclohexanone using a supported Rh catalyst containing rhodium or a combination of rhodium with another platinum metal from the group of palladium, platinum, ruthenium or iridium and which can additionally contain chromium, manganese, alkali metal and a sulphur compound is described. The catalyst of the invention is prepared from halide-free starting materials. The Rh catalyst is distinguished by a low dependence of the initial selectivity, the selectivity in the run-in state and the running-in time on the conditions of the reductive pretreatment and requires only short running-in times to the optimum state.Type: GrantFiled: September 7, 1995Date of Patent: April 29, 1997Assignee: Bayer AktiengesellschaftInventors: Hans-Josef Buysch, Christine Mendoza-Frohn, J urgen Scharschmidt, Ulrich Notheis, Rudolf J. Klee, Gerhard Darsow
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Patent number: 5583251Abstract: Isocyanates or isocyanate mixtures which contain no appreciable amounts of color causing materials are produced by phosgenating the amine corresponding to the desired isocyanate and treating the isocyanate-containing phosgenation mixture with hydrogen in the presence of a supported catalyst. The supported catalyst is in a form such that its shortest dimension is from about 0.3 to about 3.0 mm. This catalyst has a BET surface of from about 0.5 to about 150 m.sup.2 /g. No alkali material can be present in the catalyst. These isocyanates are particularly useful for the production of light-colored foams.Type: GrantFiled: March 31, 1995Date of Patent: December 10, 1996Assignee: Bayer AktiengesellschaftInventors: Hans-Josef Buysch, Manfred Gallus, Herbert Gebauer, Otto Immel, Christine Mendoza-Frohn, Reinhard Langer
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Patent number: 5510499Abstract: Ethylene glycol carbonate (EGC) can be isolated in purified form from contaminated material which contains impurities from the group comprising starting materials, by-products and/or catalysts of the preparation process in that the contaminated EGC is subjected to a fractional melt crystallization and the crystals of the purified EGC formed in this case are mechanically separated off from the remaining impurities dissolved in the residual melt.Type: GrantFiled: July 18, 1994Date of Patent: April 23, 1996Assignee: Bayer AktiengesellschaftInventors: Christine Mendoza-Frohn, Paul Wagner, Hans-Peter Wirges
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Patent number: 5508442Abstract: A bubble column reactor is described which is characterized by a slenderness ratio at a ratio of height to diameter of 2 to 50, a feed, at the bottom end of the bubble column, for the ethylene glycol carbonate (EGG) or propylene glycol carbonate (PGC) already present serving as reaction medium, one or more metering sites for the starting materials CO.sub.2 and ethylene oxide (EOX) or propylene oxide (POX) above the feed for the reaction medium, an outlet for the reaction mixture at the top end of the bubble column, a dividing apparatus connected thereto for the reaction mixture flowing off for dividing it into reaction mixture to be taken off and worked up on the one hand and reaction mixture to be recycled on the other hand and additionally a return line to the feed for the reaction mixture to be recycled. This bubble column reactor can be advantageously used in a process for the continuous preparation of EGG or PGC which is carried out in the temperature range from 100.degree. to 200.degree. C.Type: GrantFiled: May 31, 1994Date of Patent: April 16, 1996Assignee: Bayer AktiengesellschaftInventors: Paul Wagner, Christine Mendoza-Frohn, Hans-Josef Buysch
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Patent number: 5495038Abstract: This invention provides a process for the purification of diphenyl carbonate (DPC) from crude products of diphenyl carbonate production. In this process, crude products are used that have a distillable fraction consisting of over 70 wt. % diphenyl carbonate and are fractionally crystallised from the melt (fractionating melt crystallisation).Type: GrantFiled: June 5, 1995Date of Patent: February 27, 1996Assignee: Bayer AktiengesellschaftInventors: Hans-Josef Buysch, Christine Mendoza-Frohn, Johann Rechner, Norbert Schon
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Patent number: 5489696Abstract: Ethylene glycol carbonate (EGC) can be obtained in purified form from contaminated material which contains impurities from the production or work-up process, by subjecting it to treatment with activated carbon. The treatment is carried out at 40.degree.-250.degree. C. and at 1-200 bar. The activated carbon has a BET surface area of 200-3,000 m.sup.2 /g.Type: GrantFiled: April 13, 1995Date of Patent: February 6, 1996Assignee: Bayer AktiengesellschaftInventors: Christine Mendoza-Frohn, Paul Wagner, Hans-Josef Buysch
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Patent number: 5449791Abstract: A process is described for the catalytic preparation of propylene glycol carbonate (PGC) by reacting propylene oxide (POX) and CO.sub.2 in PGC as reaction medium at elevated temperature and elevated pressure and separating off from the catalyst the PGC formed. The process is carried out continuously under adiabatic temperature conditions. Per unit of time, PGC as reaction medium flows into the reactor at 7 to 350 times the amount of the PGC formed per unit of time. At all points of the reactor a CO.sub.2 excess is maintained over the other reaction partner POX. Of the effluent reaction mixture, 80 to 98% by weight are returned to the entrance of the reactor, while the remainder is worked up to give PGC. The sensible heat of the reaction product resulting from the adiabatic temperature conditions can be used for the work-up.Type: GrantFiled: May 31, 1994Date of Patent: September 12, 1995Assignee: Bayer AktiengesellschaftInventors: Paul Wagner, Christine Mendoza-Frohn, Hans-Josef Buysch
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Patent number: 5395976Abstract: In the hydrogenation of phenol with H.sub.2 over Pd supported catalysts, the ratio of the products formed, cyclohexanone and cyclohexanol, can be predetermined by specific treatment of the catalysts during the initial activation and regeneration by O.sub.2 pretreatment and H.sub.2 treatment, the following time/temperature conditions being used:a) Cyclohexanone:cyclohexanol=85:15 to 98:2a1) for initial activation, no O.sub.2 pretreatment and H.sub.2 treatment for 50-10 hours at 300.degree.-500.degree. C.;a2) for regeneration, O.sub.2 pretreatment for 30-0.5 hours at 220.degree.-380.degree. C. and H.sub.2 treatment for 2-6 hours at 150.degree.-250.degree. C.;b) Cyclohexanone:cyclohexanol=30:70 to below 85:15b1) for initial activation, O.sub.2 pretreatment for 40-3 hours at 250.degree.-500.degree. C. and H.sub.2 treatment for 2-6 hours at 150.degree.-250.degree. C.;b2) for regeneration, O.sub.2 pretreatment for 30-0.5 hours at 380.degree.-600.degree. C. and H.sub.2 treatment for 2-6 hours at 150.degree.-250.Type: GrantFiled: December 10, 1993Date of Patent: March 7, 1995Assignee: Bayer AktiengesellschaftInventors: Jurgen Scharschmidt, Christine Mendoza-Frohn, Hans-Josef Buysch, Rainer Klotzbucher
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Patent number: 5391767Abstract: Alkylene carbonates can be prepared by catalytic reaction of alkylene oxides with carbon dioxide, catalysts which can be regenerated of the formulaa[MX]/b[ZnY.sub.2 ] (III)whereinM denotes an alkali metal,X and Y independently of one another denote chlorine, bromine or iodine anda and b denote fractions or integers in a range from 0.001 to 2being employed.The catalysts (III) can be regenerated by treating with a halogen compound. The halogen compounds which can be used for this purpose belong to the group comprising hydrogen halides, inorganic and organic acid halides, interhalogen compounds and organic halides with mobile halogen.Type: GrantFiled: November 16, 1992Date of Patent: February 21, 1995Assignee: Bayer AktiengesellschaftInventors: Franz-Josef Mais, Hans-Josef Buysch, Christine Mendoza-Frohn, Alexander Klausener
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Patent number: 5350862Abstract: A process is described for the catalytic preparation of ethylene glycol carbonate by reaction of ethylene oxide and CO.sub.2 in ethylene glycol carbonate as the reaction medium at elevated temperature and at elevated pressure with work-up by distillation to separate the resulting ethylene glycol carbonate from the catalyst. The process is carried out continuously under adiabatic temperature conditions. Per unit of time, ethylene glycol carbonate as reaction medium runs into the reactor in a amount 10 to 120 times that of ethylene glycol carbonate formed per unit of time. A CO.sub.2 excess over the other reaction partner ethylene oxide is maintained at all sites of the reactor. 80 to 98% by weight of the reaction mixture flowing out is returned to the inlet of the reactor, while the remainder is worked up by distillation to give ethylene glycol carbonate. The sensible heat produced in the reaction product as a result of the adiabatic temperature conditions, is used for the work-up.Type: GrantFiled: December 3, 1992Date of Patent: September 27, 1994Assignee: Bayer AktiengesellschaftInventors: Paul Wagner, Hans-Josef Buysch, Alexander Klausener, Franz-Josef Mais, Christine Mendoza-Frohn