Did You Know...
...that the x-ray was discovered purely by accident? When German physicist Wilhelm Konrad von Roentgen was experimenting with cathode rays in 1895, he put an activated Crookes tube in a book and went out to lunch. When he returned, he discovered that a key that had also been placed in the book showed up as an image on the developed film!
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| Number | Title | Issue Date |
| 7435318 | Ionic liquids as selective additives for separation of close-boiling or azeotropic mixtures The invention relates to a process for separating close-boiling, homo- and heteroazeotropic mixtures by using ionic liquids. Due to the selectivity and unusual combination of properties of the ionic liquids the process is superior to conventional extractive rectific... | 10/14/2008 |
| 7410556 | Purification of aqueous solutions of organic acids The invention relates to a method and a device for the purification of an aqueous solution of an organic acid having a boiling point at atmospheric pressure of less than 450° C., which further has approximately 275 g carboxylate ions/1 or less, preferably 250 g car... | 08/12/2008 |
| 7332626 | Method for production of (meth) acrylic acid A method for producing acrylic acid by absorbing acrylic acid at a high ratio and obtaining an acrylic acid-containing solution of high concentration is provided. This method comprises a step of circulating part of a discharged gas from an absorption step of acrylic... | 02/19/2008 |
| 7241365 | Material for a facility for the production of anhydrous formic acid The invention relates to an apparatus and a process for the preparation of anhydrous or substantially anhydrous formic acid. This apparatus is constructed partly or entirely of substantially zirconium-free materials. The extractant employed is a liquid of the genera... | 07/10/2007 |
| 7166324 | Method, equipment, and material for creating a surface on a metal The invention relates to a method for surface treating the surface of a metal. The surface treatment is performed in a surfacing chamber, using a surfacing material, which is formed of one or more compounds and possible additives, and in which the surfa... | 01/23/2007 |
| 7128813 | Process for manufacturing high purity methacrylic acid A process for the high yield production of high purity glacial methacrylic acid (“HPMAA”) with minimization of decomposition of hydroxy isobutyric acid (HIBA). The HPMAA is substantially pure, specifically 99% pure or greater with a water content of 0.05% or les... | 10/31/2006 |
| 7048834 | Method for purification of acrylic acid The present invention provides an industrially easy and economical method for purification of acrylic acid which enables to efficiently eliminate impurities from a crude acrylic acid containing aldehydes as the impurities while the formation of acrylic acid polymer ... | 05/23/2006 |
| 7048835 | System and method for acetic acid recovery during terephthalic acid production A distillation system and method for recovering acetic acid from a feed stream containing acetic acid and water stream generated during terephthalic acid production. The invention includes a dehydration column utilizing azeotropic distillation to recover the acetic ... | 05/23/2006 |
| 6946060 | Purification of N,N-dimethylacetamide A method to purify N,N-dimethylacetamide (DMAc) from an aqueous solution containing acetic acid as a contaminant. Two fractional distillation columns are arranged in a series. The solution containing the contaminant is provided to the first column with a temperature... | 09/20/2005 |
| 6926810 | Process for obtaining an organic acid from an organic acid ammonium salt, an organic acid amide, or an alkylamine organic acid complex Disclosed herein are methods for the recovery of an organic acid, such as a heat stable lactic acid, from a feed stream which contains at least one of an organic acid amide, an organic acid ammonium salt, or an alkylamine-organic acid complex. The feed stream is mix... | 08/09/2005 |
| 6793777 | Method for separating and purifying an aqueous mixture that mainly consists of acetic acid and formic acid The invention relates to a method for separating and purifying an aqueous mixture that mainly consists of acetic acid, formic acid and high-boiling substances by extraction with a solvent in a cyclic process. The inventive method is characterized in that the flow of... | 09/21/2004 |
| 6695952 | Method for the separation of and purification of an aqueous mixture consisting of the main components acetic acid and formic acid A method for the separation and purification of an aqueous mixture of main components, namely acetic acid and formic acid and non-volatiles by extraction, uses a solvent in a circulatory system. A raffinate stream is mixed with the larger proportion of wa... | 02/24/2004 |
| 6179966 | Method for producing acrylic acid The present invention concerns a method for producing acrylic acid which involves subjecting an acrylic acid-containing aqueous solution obtained by catalytic vapor phase oxidation of propylene and/or acrolein to evaporation whereby an acrylic acid-contai... | 01/30/2001 |
| 5980696 | Dehydration of acetic acid by azeotropic distillation in the production of an aromatic acid An improved process for preparing an aromatic dicarboxylic acid wherein the improvement resides in dehydrating and recovering solvent from a feed stream having from 20% to 40% by weight water via azeotropic distillation with organic phase reflux using an ... | 11/09/1999 |
| 5976324 | Removal of water from reaction mixtures A process as been found for the removal of water from reaction mixtures of acids or acid anhydrides or of aqueous alkali metal hydroxide solutions with alcohols using vapor permeation/pervaporation at the boiling point of the reaction mixture, which inclu... | 11/02/1999 |
| 5873981 | Recovery of anhydrous acids A is a process for removing water from an alkanesulfonic acid such as methanesulfonic acid or ethanesulfonic acid by mixing an azeotropic excess of a phenolic compound with water and the alkanesulfonic acid, then boiling off substantially all of the water... | 02/23/1999 |
| 5624566 | Method and apparatus for recovering carboxylic acids from dilute solutions A method for recovering carboxylic acids from a dilute aqueous solution thereof having a concentration below about ten percent (10%) by weight, which includes passing the dilute acid solution through a reverse osmosis separator, thereby producing a permea... | 04/29/1997 |
| 5603813 | Purifying distillation of vinyl formate Vinyl formate containing formic acid, acetaldehyde and water following synthesis is separated from formic acid and water in a first distillation stage and from acetaldehyde in a second stage to give pure vinyl formate.... | 02/18/1997 |
| 5492625 | Method of recovering carboxylic acids from dilute solutions A method for recovering carboxylic acids from a dilute aqueous solution thereof having a concentration below about ten percent (10%) by weight, which includes passing the dilute acid solution through a reverse osmosis separator, thereby producing a permea... | 02/20/1996 |
| 5399751 | Method for recovering carboxylic acids from aqueous solutions Disclosed is a method for recovering carboxylic acids having from one to ten carbon atoms, and particularly formic acid, acetic acid and mixtures of formic and acetic acids, from aqueous solutions, in which the aqueous solution is contacted with solvent c... | 03/21/1995 |
| 5384413 | Process for the preparation of tetrafluorophthalic acid and/or tetrafluorophthalic anhydride The present invention relates to a process for the preparation of tetrafluorophthalic acid and/or tetrafluorophthalic anhydride by reacting a compound of the formula ##STR1## in which X is a radical ##STR2## which is optionally mono- or pol... | 01/24/1995 |
| 5312935 | Purification of fluorinated carboxylic acids Fluorinated carboxylic acids which do not have the required purity for use as emulsifier in the polymerization of fluorinated monomers can, if necessary after prior de-watering, be treated with oxidants, whereupon the isolation of the pure product is carr... | 05/17/1994 |
| 5296639 | Adipic acid purification A process for purification of adipic acid during crystallization by modifying the crystal morphology to decrease incorporation of impurities through the introduction of an effective amount of an additive to the crystallizing solution.... | 03/22/1994 |
| 5206433 | Preparation of formic acid Anhydrous or substantially anhydrous formic acid is prepared by hydrolyzing methyl formate in the presence of a formamide and then obtaining the formic acid from the hydrolysis mixture by distillation, by a method in which the hydrolysis is carried out in... | 04/27/1993 |
| 5173156 | Dehydration of formic acid by extractive distillation Formic acid cannot be completely removed from formic acid--water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from mixtures containing it and water by using extractive distillation in which ... | 12/22/1992 |
| 5154800 | Dehydration of acrylic acid by extractive distillation Acrylic acid cannot be completely separated from water by conventional distillation or rectification because of the minimum boiling azeotrope. Acrylic acid can be readily separated from water by extractive distillation. Effective agents are dimethylsulfox... | 10/13/1992 |
| 5104492 | Recovery of carboxylic acids from water by precipitation from organic solutions Carboxylic acids are recovered from wet organic solutions by reducing the solutions' water content thus causing the acids to precipitate as recoverable crystals.... | 04/14/1992 |
| 5059327 | Cross-linked separation membrane and process for pervaporation A preparation membrane for pervaporation which comprises a crosslinked reaction mixture of a polyvinyl alcohol or polyvinyl alcohol copolymer and a polystyrene sulfonic acid or polystyrene sulfonic acid copolymer. A method for separating a mixture of wate... | 10/22/1991 |
| 5006205 | Dehydration of formic acid by extractive distillation Formic acid cannot be completely removed from formic acid and water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from formic acid - water mixtures by extractive distillation in which the ext... | 04/09/1991 |
| 4978430 | Method for dehydration and concentration of aqueous solution containing organic compound An improved method for dehydration and concentration of an aqueous solution containing an organic compound is disclosed. The solution is evaporated to produce a gaseous mixture comprising an organic compound vapor and a water vapor. The water vapor is sel... | 12/18/1990 |
| 4938846 | Preparation of anhydrous alkanesulfonic acid A process for the removal of water from a lower alkanesulfonic acid-water mixture by causing the mixture to run down the internal walls of two vertical evaporator columns operated in series, is disclosed herein.... | 07/03/1990 |
| 4935100 | Dehydration of formic acid by extractive distillation Formic acid cannot be completely removed from formic acid and water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from formic acid - water mixtures by extractive distillation in which the ext... | 06/19/1990 |
| 4898644 | Removal of volatile acids from aqueous solutions A process for removing volatile acids from aqueous solutions which involves steam stripping a volatile acid from an aqueous solution and contacting the vaporized acid with a reactable cation to form a salt of the acid. A preferred embodiment of apparatus ... | 02/06/1990 |
| 4877490 | Dehydration of formic acid by extractive distillation with dicarboxylic acids Formic acid cannot be completely removed from formic acid and water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from formic acid--water mixtures by extractive distillation in which extracti... | 10/31/1989 |
| 4838998 | Process for separating sulfuric acid and carboxylic acids The amount of water required to effect efficient separation of a mixture of sulfuric acid and carboxylic acids by distillation, is reduced, by diluting the mixture while in the distillation column in a prescribed manner with sufficient water to provide a ... | 06/13/1989 |
| 4786370 | Dehydration of formic acid by extractive distillation Formic acid cannot be completely removed from formic acid and water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from formic acid - water mixtures by extractive distillation in which the ext... | 11/22/1988 |
| 4736062 | Process for preparing methacrylic acid A process is disclosed for producing an alpha-, beta-ethylenically unsaturated monocarboxylic acid compound which comprises the aldol-type condensation of a saturated aliphatic monocarboxylic acid compound under vapor phase conditions in the presence of a... | 04/05/1988 |
| 4735690 | Dehydration of impure formic acid by extractive distillation Impure formic acid cannot be completely removed from formic acid-water-impurity mixtures by distillation because of the presence of the maximum azeotrope between formic acid and water. Formic acid can be readily removed from mixtures containing it, water ... | 04/05/1988 |
| 4692219 | Separation of formic acid from acetic acid by extractive distillation Formic acid cannot be easily removed from acetic acid by distillation because of the closeness of their vapor pressures. Formic acid can be readily removed from acetic acid by extraction distillation. Typical extractive distillation agents are carboxylic ... | 09/08/1987 |
| 4670105 | Dehydration of propanoic acid by extractive distillation Propanoic acid cannot be completely removed from propanoic-water mixtures by distillation because of the presence of the minimum azeotrope. Propanoic acid can be readily removed from mixtures containing it and water by using extractive distillation in whi... | 06/02/1987 |
