Including Distillation Patents (Class 570/178)
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Patent number: 5382725Abstract: 1,3-dihalobenzene, particularly 1,3-dichlorobenzene, is produced in high efficiency from a mixture containing the subject compound and its corresponding 1,4-isomer by a special process in which the dihalobenzene mixture is treated with polyethylene glycols of varying molecular weight and the resulting slurry is filtered to remove a complex of 1,4-dihalobenzene and polyethylene glycol as a solid and the 1,3-dihalobenzene as the filtrate.The 1,4-dihalobenzene complexed with the polyethylene glycol can be recovered by a flash distillation under vacuum and the residue containing the polyethylene glycol can be recycled.The purity of the 1,3-dihalobenzene obtained by this process can further be improved by subjecting the product obtained after the polyethylene glycol treatment to a low temperature crystallization process where 1,3-dihalobenzene can be selectively crystallized to a purity of above 99%.Type: GrantFiled: February 18, 1994Date of Patent: January 17, 1995Assignee: Standard Chlorine of Delaware Inc.Inventors: Jacob George, Kantilal B. Desai, Francis M. Schoeffler
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Patent number: 5382724Abstract: A process for purifying 1,1,1,2-tetrafluoroethane which comprises allowing an HF-containing 1,1,1,2-tetrafluoroethane-concentrated fraction to contact at a low temperature with hydrofluoric acid which is an extraction solvent and has an HF concentration equal to or higher than an HF concentration at a water-HF azeotropic point, thereby effecting two-phase separation, and subsequently recovering 1,1,1,2-tetrafluoroethane from the separated lower phase, wherein hydrofluoric acid to be used as the extraction solvent has a concentration of from 38 to 70% by weight, and the extraction and two-phase separation steps are effected at a temperature of from -35.degree. to 35.degree. C. According to the purification process, HF can be recovered economically from a 1,1,1,2-tetrafluoroethane fraction containing a small amount of HF.Type: GrantFiled: March 23, 1994Date of Patent: January 17, 1995Assignee: Showa Denko Kabushiki KaishaInventors: Hiromoto Ohno, Tatsuharu Arai, Koichi Katamura, Sadayoshi Yuge, Haruyuki Kawai, Yasuaki Morito
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Patent number: 5346594Abstract: A process for purification of crude, 1,1-dichloro-1-fluoroethane includes the steps of treating a mixture of crude, 1,1-dichloro-1-fluoroethane and hydrogen fluoride with chlorine in the presence of a Lewis acid, and distilling to recover purified 1,1-dichloro-1-fluoroethane, wherein hydrogen fluoride is present during the treatment with chlorine at a ratio of at least 5% by weight with respect to the mixture of crude, 1,1-dichloro-1-fluoroethane and hydrogen fluoride.Type: GrantFiled: January 12, 1993Date of Patent: September 13, 1994Assignee: Solvay (Societe Anonyme)Inventors: Paul Lechaude, Gilles Darago, Philippe Krafft, Jean-Pierre Catinat
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Patent number: 5346595Abstract: The invention generally relates to a process for the purification of a component of a binary azeotrope in which the composition of the azeotrope changes by about 10 mole percent with pressure comprising:(a) subjecting a binary azeotrope to a distillation step in which most of one of the binary components is removed as distillate (distillate 1) with the bottoms (bottoms 1) enriched in the other component;(b) subjecting distillate 1 to at least one additional distillation step conducted at a different pressure in which most of the component recovered as bottoms 1 is removed as distillate 2 with the bottoms 2 enriched in the component enriched in distillate 1;(c) optionally repeating step (b) as many times as desired; and(d) recovering the desired purified component.The invention is particularly useful in the purification of pentafluoroethane in a pentafluoroethane/chloropentafluoroethane azeotrope.Type: GrantFiled: February 23, 1993Date of Patent: September 13, 1994Assignee: AlliedSignal Inc.Inventors: Paul G. Clemmer, Hsueh S. Tung, Addison M. Smith
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Patent number: 5336377Abstract: 2-Chloro-1,1-difluoroethylene (R-1122) is removed from 1,1,1,2-tetrafluoroethane (R-134a) by contacting the R-134a in the vapor phase with chlorine in the presence of ultraviolet light providing an exposure of at least about 2 watts-hour/kg.Type: GrantFiled: December 18, 1991Date of Patent: August 9, 1994Assignee: Allied-Signal Inc.Inventors: Stephen F. Yates, Daniel F. Harnish, Addison M. Smith
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Patent number: 5324873Abstract: Hydrogen fluoride and 1,1,1-trifluoro-2-chloroethane forms an azeotropic mixture. A mixture comprising hydrogen fluoride and 1,1,1-trifluoro-2-chloroethane is phase separated when it is cooled to a temperature below 7.degree. C. 1,1,1-Trifluoro-2-chloroethane is purified effectively from the mixture by cooling the mixture to form an upper liquid phase and a lower liquid phase and distilling the lower liquid phase so that the hydrogen fluoride is removed as an azeotropic distillate and 1,1,1-trifluoro-2-chloroethane substantially free from hydrogen fluoride is obtained as a bottom product.Type: GrantFiled: February 12, 1993Date of Patent: June 28, 1994Assignee: Daikin Industries LimitedInventors: Takehide Tsuda, Nobuyoshi Iwashita, Satoshi Komatsu, Satoshi Koyama
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Patent number: 5324393Abstract: A method for preventing fouling of ethylene dichloride distillation units which comprises treating the feed to such unit with a fouling preventing amount of a composition comprising (a) 2-15 weight % of an oil soluble polyacrylate ester or methacrylate ester with alcohol radical of the ester group containing from C.sub.4 -C.sub.22 carbon atoms which contains between 0.1-25 mole % of amino alcohol ester groups; (b) 20-40 weight % a phenylene diamine compound having the formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are the same or different and are hydrogen, C.sub.1 -C.sub.20 alkyl, C.sub.1 -C.sub.20 aryl, C.sub.1 -C.sub.20 alkaryl or C.sub.1 -C.sub.20 aralkyl, with the proviso that at least one of R.sub.1, R.sub.2, R.sub.3 or R.sub.4 is hydrogen; and (c) the balance is a heavy aromatic solvent.Type: GrantFiled: April 15, 1993Date of Patent: June 28, 1994Assignee: Nalco Chemical CompanyInventor: Michael K. Poindexter
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Patent number: 5318673Abstract: Process for the purification of crude 1,1-dichloro -1-fluoroethane by treatment with chlorine in the presence of an organic free radical initiator and then distillation.Type: GrantFiled: April 6, 1993Date of Patent: June 7, 1994Assignee: Solvay (Societe Anonyme)Inventors: Rene Walraevens, Francine Janssens, Jean-Pierre Catinat
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Patent number: 5306850Abstract: Process for purifying a hydrofluoroalkane with respect to impurities which are less volatile than the hydrofluorocarbon, by distillation in the presence of an acid-scavenger, for example a C.sub.3 -C.sub.8 olefin.Type: GrantFiled: March 31, 1993Date of Patent: April 26, 1994Assignee: Solvay (Societe Anonyme)Inventor: Gilles Darago
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Patent number: 5276225Abstract: A halocarbon product made from the reaction of excess hydrogen fluoride with a halocarbon, containing excess hydrogen fluoride as an azeotrope is purified by fluorination in the presence of additional halocarbon or halo-olefin.Type: GrantFiled: March 31, 1993Date of Patent: January 4, 1994Assignee: Elf Atochem S.A.Inventor: Bernard Berthe
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Patent number: 5268120Abstract: To replace the cleaning compositions based on 1,1,2-trichloro-1,2,2-trifluoroethane (F113), the invention proposes a composition comprising, on a weight basis, 60 to 90% of 1,1-dichloro-1-fluoroethane (F141b), 9 to 33% of 1,1,1,3,3-pentafluorobutane (F365 mfc) and 1 to 7% of methanol. These three compounds form a positive azeotrope (b.p.=29.1.degree. C. at normal pressure).The composition, optionally stabilized, can be employed for the cleaning and/or drying of solid surfaces, in particular for the defluxing of printed circuits and for the degreasing of mechanical components.Type: GrantFiled: April 30, 1992Date of Patent: December 7, 1993Assignee: Elf Atochem, S.A.Inventor: Pascal Michaud
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Patent number: 5225048Abstract: The invention relates to a distillation method and an apparatus for the concentration and purification of water-containing liquid chemicals. The distillation is performed using constant, predetermined distillation parameters.Type: GrantFiled: January 29, 1991Date of Patent: July 6, 1993Assignee: Athens Corp.Inventor: Wallace I. Yuan
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Patent number: 5211817Abstract: A product stream containing, inter alia, HCl, HF and fluorocarbons which form close boiling point azeotropes with HF is subjected to distillation using sidestream rectification in order to effect energy efficient separation of selected fluorocarbon/HF azeotropes from one another.Type: GrantFiled: March 11, 1992Date of Patent: May 18, 1993Assignee: Imperial Chemical Industries PLCInventors: Stephen J. Adams, Andrew M. Taylor
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Patent number: 5200431Abstract: Method for separating 1,1,1,2-tetrafluoroethane from a mixture thereof with chlorine-containing halogenated hydrocarbons such as HCFC's 1122, 124, 114, 114a and 133a which comprises adding an extraction agent to the mixture and extractively distilling the mixture in an extractive distillation zone from which HFA 134a containing less than 10 ppm of chlorinated contaminants is recovered. Suitable extraction agents include trichloroethylene, perchloroethylene, alpha-pinene and cyclohexane.Type: GrantFiled: August 21, 1991Date of Patent: April 6, 1993Assignee: Imperial Chemical Industries PLCInventors: Pravin K. Dattani, John D. Scott, Barry W. Farrant, Charles J. Shields
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Patent number: 5196616Abstract: A process for separating and recovering an organic phase (e.g., fluorocarbons such as chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons and perfluorocarbons) from a feed stream of a mixture of fluorocarbons and hydrogen fluoride, wherein the mixture is characterized as forming at least one azeotrope or azeotrope-like composition involving at least one fluorocarbon and hydrogen fluoride, by passing the fluorocarbon/HF mixture feed stream through the feed side of a semipermeable membrane unit and then further separating a fluorocarbon-depleted hydrogen fluoride permeate stream and a fluorocarbon enriched residual stream exiting the membrane unit by conventional distillation. An essentially pure fluorocarbon phase and hydrogen fluoride phase are recovered from the distillation with the azeotrope or azeotrope-like distillate being recycled to the inlet of the semipermeable membrane unit.Type: GrantFiled: October 18, 1991Date of Patent: March 23, 1993Assignee: E. I. Du Pont de Nemours and CompanyInventors: Kung H. Lee, Domenic J. Barsotti, Edward K. Sakata
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Patent number: 5175380Abstract: Mixtures of perfluorinated alkyl bromides or alkylene dibromides containing perfluorinated iodine compounds are irradiated with electromagnetic radiation in the wavelength range from 230 to 500 nm and brought into contact, either during the irradiation or directly thereafter, with at least one of the following agents: active charcoal, certain finely divided metals, lower aliphatic alcohols, chlorine, bromine, oxygen, hydrogen peroxide, aqueous or alcoholic solutions of alkali metal compounds with certain inorganic anions or lower aliphatic alcohols. After removal of the agent and if appropriate distillation, products which contain less than 0.0005% by weight of iodine compounds and can be employed, for example, in the medical sector can be obtained.Type: GrantFiled: May 14, 1992Date of Patent: December 29, 1992Assignee: Hoechst AktiengesellschaftInventor: Klaus Raab
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Patent number: 5132474Abstract: The present invention provides a method of effectively recovering a hydrocarbon halide and the use of a specific aprotic polar compound for said method. Thus, the present invention provides a method of recovering a hydrocarbon halide comprising absorbing the hydrocarbon halide into an aprotic polar compound which has a 5 or 6 membered ring and a nitrogen atom at an alpha-position of a carbonyl group. In the present method, the absorbed hydrocarbon halide can be easily recovered by usual methods.Type: GrantFiled: December 20, 1991Date of Patent: July 21, 1992Assignee: Nippon Paint Co., Ltd.Inventor: Fujio Mashio
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Patent number: 5129997Abstract: A process for the preparation of mixtures of chlorotetrafluoroethane and octafluorocyclobutane from the gas stream from the pyrolysis of chlorodifluoromethane at temperatures above 600.degree. C. is described in which the principal constituents tetrafluoroethylene and hexafluoropropylene as well as hydrogen chloride are removed in advance. The mixtures are obtained by withdrawal as a side fraction during the rectifying distillation of the residue remaining, a clean separation of the perfluorocyclobutenes advantageously taking place. The mixtures are used for obtaining hexafluoropropylene by pyrolysis.Type: GrantFiled: April 10, 1991Date of Patent: July 14, 1992Assignee: Hoechst AktiengesellschaftInventors: Thomas Schottle, Herbert Weber, Werner Dostler, Karl Rettenbeck
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Patent number: 5105035Abstract: Vinylidene chloride and other unsaturated impurities are removed from HCFC-141b by reaction with hydrogen over a catalyst such as palladium on alumina.Type: GrantFiled: May 29, 1991Date of Patent: April 14, 1992Assignee: Allied-Signal Inc.Inventors: Li Wang, Stephen F. Yates, Russell W. Johnson
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Patent number: 5094773Abstract: Azeotropes of HF and 2,2-dichloro-1,1,1-trifluoroethane and of HF and 2-chloro-1,1,1,2-tetrafluoroethane. Process for the separation of hydrogen fluoride (HF), 2,2-dichloro-1,1,1-trifluoroethane (FC-123), and/or 2-chloro-1,1,1,2-tetrafluoroethane (FC-124) from mixtures containing them by controlling the molar ratio of HF/FC-123 in the mixture prior to subjecting the mixture to azeotropic distillation.Type: GrantFiled: April 9, 1990Date of Patent: March 10, 1992Assignee: E. I. Du Pont de Nemours and CompanyInventors: Leo E. Manzer, V. N. Mallikarjuna Rao, Richard T. Rockwell, Michael A. Sisk, Edwin J. Warwas, Roy Winteringham
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Patent number: 5087329Abstract: Separating pentafluoroethane from a mixture of pentafluoroethane and chloropentafluoroethane by adding a fluorocarbon extractive agent having 1-4 carbon atoms, and optionally containing hydrogen and/or chlorine, in an extractive distillation zone to recover pentafluoroethane substantially free of chloropentafluoroethane in the overhead product stream.Type: GrantFiled: May 16, 1991Date of Patent: February 11, 1992Assignee: E. I. Du Pont de Nemours and CompanyInventor: Vinci M. Felix
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Patent number: 5049241Abstract: Process of separating hydrogen chloride and tetrafluoroethylene by extractively distilling a mixture thereof in the presence of an extractant that substantially alters the relative volatilities of the hydrogen chloride and the tetrafluoroethylene, for example, a perhalogenated organic extractant, such as perfluorocyclobutane, hexafluoropropylene or 1,1,2-trifluoro-1,2,2-trichloroethane.Type: GrantFiled: March 27, 1990Date of Patent: September 17, 1991Assignee: E. I. du Pont de Nemours and CompanyInventors: Glenn F. Leverett, Jan Wit
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Patent number: 5001287Abstract: A process for treating an impure mixture consisting essentially of at least one olefinic impurity and at least one saturated halocarbon selected from fluorocarbons and fluorohydrocarbons by contacting the mixture with a source of hydrogen in the presence of a hydrogenation catalyst, whereby the olefinic impurity is converted to a hydrogenated form thereof, to produce a treated mixture consisting essentially of the hydrogenated form of the olefinic impurity or impurities and the saturated halocarbon or halocarbons from the impure mixture.Type: GrantFiled: February 2, 1989Date of Patent: March 19, 1991Assignee: E. I. Du Pont de Nemours and CompanyInventors: Richard E. Fernandez, V. N. Mallikarjuna Rao
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Patent number: 4975156Abstract: 1,1-Dichloro-1-fluoroethane, 1-chloro-1,1-difluoroethane and hydrogen fluoride are separated from their liquid mixtures, such as liquid mixtures resulting from the hydrofluorination, of 1,1,1-trichloroethane or vinylidene chloride. 1,1-Dichloro-1-fluoroethane and 1-chloro-1,1-difluoroethane are first separated by distillation into their respective mixtures with hydrogen fluoride, which are thereafter subjected to parallel phase separations resulting in two hydrogen fluoride-enriched liquid phases, a 1-chloro-1,1-difluoroethane-enriched liquid phase and a 1,1-dichloro-1-fluoroethane-enriched liquid phase. 1-Chloro-1,1-difluoroethane and 1,1-dichloro-1-fluoroethane are purified from the respective halohydrocarbon-enriched liquid phases by distillation. The hydrogen fluoride-enriched stream generated from the phase separation of the hydrogen fluoride/1,1-dichloro-1-fluoroethane mixture is recycled to the hydrofluorination reaction mixture.Type: GrantFiled: May 4, 1989Date of Patent: December 4, 1990Assignee: Atochem North America, Inc.Inventor: John A. Wismer
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Patent number: 4973774Abstract: Chlorofluorohydrocarbons contaminated with unwanted isomers during the process for their manufacture are purified by reacting the mixture with alcohol solutions of alkali metal and then separating the ether derivatives of the isomers from the mixture.Type: GrantFiled: November 2, 1989Date of Patent: November 27, 1990Assignee: E. I. Du Pont de Nemours and CompanyInventors: Shlomo M. Rozen, Bruce E. Smart
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Patent number: 4950364Abstract: 1,1-Dichloro-1-fluroethane and 1,1,1,3,3-pentafluorobutane are separated from their liquid mixtures, such as liquid mixtures resulting from the hydrofluorination of 1,1,1-trichloroethane or vinylidene chloride. 1,1-Dichloro-1-fluoroethane and 1,1,1,3,3-pentafluorobutane are completely separated by distillation, by adding to the mixture thereof a liquid containing at least about 3 moles of hydrogen fluoride per mole of 1,1-dichloro-1-fluoroethane in the mixture subject to separation.Type: GrantFiled: May 4, 1989Date of Patent: August 21, 1990Assignee: Pennwalt CorporationInventor: John A. Wismer
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Patent number: 4944846Abstract: Process for the separation of hydrogen fluoride (HF), 2,2-dichloro-1,1,1-trifluoroethane (FC-123), and/or 2-chloro-1,1,1,2-tetrafluoroethane (FC-124) from mixtures containing them by controlling the molar ratio of HF/FC-123 in the mixture prior to subjecting the mixture to azeotropic distillation.Type: GrantFiled: August 1, 1988Date of Patent: July 31, 1990Assignee: E. I. DuPont de Nemours and CompanyInventors: Leo E. Manzer, V. N. Mallikarjuna Rao, Richard T. Rockwell, Michael A. Sisk, Edwin J. Warwas, Roy Winteringham
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Patent number: 4911792Abstract: Process for the separation of HF, 2,2-dichloro-1,1,1-trifluoroethane (FC-123) and/or 2-chloro-1,1,1,2-tetrafluoroethane (FC-124) mixture by subjecting the mixture to a temperature from about -80.degree. C. to about 40.degree. C. and a pressure from about 0.10 MPa to about 3.55 MPa in a separation zone, whereby an organic phase having less than 15 mole percent of HF is formed as the bottom layer in the separation zone and an acid phase having at least 93 mole percent of HF is formed at the top in the separation zone.Type: GrantFiled: August 1, 1988Date of Patent: March 27, 1990Assignee: E. I. Du Pont de Nemours and CompanyInventors: Leo E. Manzer, V. N. Mallikarjuna Rao, Richard T. Rockwell, Michael A. Sisk, Edwin J. Warwas, Roy Winteringham
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Patent number: 4898645Abstract: A process is described for the production of pure tetrafluoroethylene from a gas formed in the pyrolysis of a fluorocarbon compound having 1 to 4 carbon atoms, which can contain a hydrogen atom and a chlorine atom. The pyrolysis gas, after hydrogen chloride or hydrogen fluoride and also if necessary steam have been separated off, is condensed under pressure and distilled in a plurality of columns, in the first column the low boilers being distilled off, preferably with a reflux ratio of 6 to 15 kg per kg of tetrafluoroethylene produced, and in the second column tetrafluoroethylene, preferably with a reflux ratio of 3 to 5 kg per kg of tetrafluoroethylene produced. Per kg of tetrafluoroethylene produced, from 0.6 to 2 kg of difluoromonochloromethane are fed into the second column as a distillation aid. The novel process makes it possible to produce pure tetrafluoroethylene at comparatively reduced energy and apparatus costs.Type: GrantFiled: August 30, 1988Date of Patent: February 6, 1990Assignee: Hoechst AktiengesellschaftInventors: Hartmut Voigt, Reinhold Freudenreich
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Patent number: 4801763Abstract: A process is disclosed for purifying and stabilizing a mixture of regular chlorotrifluoroethyelne telomers of formula RCXCl(CF.sub.2 CFCl).sub.n Br from bromine-containing irregular telomer impurities of similar molecular weight. The telomer mixture is produced by reacting chlorotrifluoroethylene with a telogen of formula RCXClBr, where R is CF.sub.2 Br, or Cl, and X is Cl or F. The telomer mixture is then chlorinated using either elevated temperature alone (100.degree. C.-350.degree. C.), or a combination of elevated temperatures (100.degree. C.-200.degree. C.) and light energy primarily of the wavelength region greater than about 3000.degree.A. Under these conditions, CFClBr telomer end group of the regular or normal telomer is chlorinated to form --CFCl.sub.2 end groups, while the bromine-containing irregular telomer impurities (whose bromine-containing end groups are substantially only --CF.sub.2 Br) are substantially not chlorinated.Type: GrantFiled: July 27, 1987Date of Patent: January 31, 1989Assignee: Occidental Chemical CorporationInventors: James J. Maul, Bobby F. Dannels, David Y. Tang
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Patent number: 4766261Abstract: Fluorocarbons are purified and toxicity substantially reduced by contact with a substantially dry, strongly basic and strongly nucleophilic alkali or alkaline earth metal compound, and separating the decomposition products which form.Type: GrantFiled: December 10, 1985Date of Patent: August 23, 1988Assignee: Adamantech, Inc.Inventor: Thomas W. Bierl
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Patent number: 4548701Abstract: A method for recovery of extraction solvent from a dissolved solute wherein halogen gas evolution and halogen compound retention in the solute are minimized comprises heating a solution of a halogenated organic solvent and the extracted solute in the presence of an ammonium, Group I metal or Group II metal salt of an acid of carbon number 1 to 6, such as ammonium bicarbonate, ammonium carbonate, ammonium formate, sodium carbonate, sodium formate, or calcium formate, to recover the solvent and the solute.Type: GrantFiled: December 19, 1983Date of Patent: October 22, 1985Assignee: Amoco CorporationInventor: William F. Wolff