Abstract: The invention relates to novel composites for capture, e.g., absorption, of condensable gases and vapors from atmospheric sources, and gas or vapor streams, and the recovery of the condensed gases and vapors from the composites, as well as passive methods absent of external sources of energy for conducting the capturing and recovery processes. The composites include a hydrophilic matrix; hydrophilic solids embedded or immersed in the matrix, in close proximity to each other; and porogenic material embedded in the matrix, having a size larger than the hydrophilic solids; wherein selective removal of the porogenic material from the matrix forms a hierarchically porous matrix.

Abstract: Provided is a method for purifying a waste solvent by removing carbon dioxide contained in a waste solvent derived from supercritical waste liquid generated after supercritical drying by a decompression process, and removing ammonia by a multi-stage distillation process to obtain a solvent of high purity, which can be reused in producing silica aerogel or a silica aerogel blanket.

Abstract: It is intended to provide a method capable of suppressing distillation apparatus corrosion as a method for producing acetic acid, comprising the step of distilling a crude acetic acid solution containing acetic acid and an impurity having a higher boiling point than that of acetic acid to purify the acetic acid. The method for producing acetic acid of the present invention comprises the step described above, wherein the distillation of the crude acetic acid solution is performed under a condition involving a distillation column bottom temperature of not more than 165° C. An acetic acid concentration in the crude acetic acid solution to be subjected to the distillation is preferably not less than 90 mass %. Examples of the impurity having a higher boiling point than that of acetic acid include acetate salts, acetic anhydride, and propionic acid. A column bottom pressure of the distillation column is preferably less than 0.255 MPaG.

Abstract: A process for producing an acrylate product. The process comprises the step of providing a crude product stream comprising the acrylate product and an alkylenating agent. The process further comprises the step of separating at least a portion of the crude product stream to form an alkylenating agent stream and an intermediate product stream. The alkylenating agent stream comprises at least 1 wt % alkylenating agent and the intermediate product stream comprises acrylate product. The separating is performed in at least one column at an operating pressure ranging from 40 kPa to 80 kPa.

Abstract: A method for producing of ultra-clean and high-purity electronic acetic acid is disclosed. The method including following steps: Step 1, industrial acetic acid is fast distilled; Step 2, filtering the fraction by membrane of 0.05˜0.3 ?m aperture; Step 3, rectification; Step 4, membrane filtration again. Due to the adoption of the technical scheme above, the ultra-clean and high-purity electronic grade acetic acid which purity is 99.8% is produced. The content of single metal ion is lower than 1 ppb and the content of particulates which is ?0.5 ?m is lower than 5 pcs/ml. The method of the invention will help to reduce energy consumption, to simplify the operation, and to achieve the high security.

Abstract: A method for recovering acetic acid from an aqueous feed stream containing acetic acid and, in particular, a stream generated during terephthalic acid production includes feeding a water-rich feed stream to a liquid-liquid extraction column, which includes a guard bed near the top thereof for conversion of alcohol within the feed stream by reaction with acetic acid to the corresponding ester, and removing residual water from acetic acid in an azeotropic distillation column by feeding water-poor feed streams from the extraction column to the distillation column at a height at which the mixture has a similar water concentration. The liquid-liquid extraction column produces an extract of an extraction solvent and acetic acid which is sent to the azeotropic distillation column to separate residual water and acetic acid.

Abstract: An improved process for separation of liquid mixtures involves vapor stripping followed by mechanical compression of the vapor which is then exposed to a permeation membrane for separation of the compressed vapor. The apparatus for separating a liquid mixture of two or more solvents comprises components a stripping column, at least one over-head compressor and, thereafter, at least one selectively permeable membrane wherein the membrane separates the components of the vapor based on the different sorption and diffusion characteristics.

Abstract: The invention disclosed relates to an apparatus and method for recovering acetic acid from an aqueous feed stream containing acetic acid, in particular a stream generated during terephthalic acid production. The apparatus includes: a liquid-liquid extraction column to which water-rich feed streams are fed, having a guard bed situated near the top and within the extraction column for conversion by reaction with acetic acid of alcohol within the mixture to the corresponding ester; and an azeotropic distillation column to remove residual water from acetic acid, to which water-poor feed streams are fed directly at a height of the azeotropic distillation column at which the mixture therein has a similar water concentration. The liquid-liquid extraction column produces an extract comprising an extraction solvent and acetic acid which is sent to the azeotropic distillation column to separate residual water and acetic acid.

Abstract: Processes for removing water from organic solvents, such as ethanol. The processes include distillation in two columns operated at sequentially higher pressure, followed by treatment of the overhead vapor by one or two membrane separation steps.

Abstract: Processes for removing water from organic solvents, such as ethanol. The processes include distillation in two columns operated at sequentially higher pressure, followed by treatment of the overhead vapor by one or two membrane separation steps.

Abstract: 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 acid in conjunction with a condenser system to recover the energy.

Abstract: The invention relates to a process for recovering and producing chemicals in a pulp production process where organic chemicals, such as formic acid and acetic acid, are used as cooking chemicals. The process of the invention is based on regeneration of cooking acids and formation of additional cooking acids and furfural by evaporating the cooking liquor and then separating acetic acid, formic acid, furfural and water. The separation is preferably carried out by distillation using the furfural formed in the process as a distilling aid in the distillation.

Abstract: 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 raffinate is fed to a solvent stripping column (11) with the major part of the water in order to remove the water from the cycle. The flow of extract is fed to a solvent recovery distillation column (8). In a first step, a mixture (A) that consists of water and solvent, is separated by overhead distillation. A mixture (B) that consists of acetic acid, formic acid and high-boiling substances is separated via a sump. Once the formic acid is removed in a column (29), mixture (B) is separated in an acetic acid distillation column to give pure acetic acid and high-boiling substances.

Abstract: 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 water from a solvent stripper column (11) for the removal of water. The extraction stream is introduced into a solvent distillation column (8), from which in a first step involving the use of a mixture (A) containing a larger proportion of the solvent is separated out via a header and a mixture (B) of formic acid, water and solvent is separated out via a side offtake and a mixture (C) of acetic acid and non-volatiles is also separated out. A mixture (B) is introduced into a formic acid distillation column (4) for further processing, and a mixture (C) is introduced into an acetic acid distillation column (5), and purified acetic acid is subsequently isolated in the acetic acid distillation column (5) from the header.

Abstract: Disclosed is 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 acid in conjunction with a condenser system to recover the energy. The dehydration column operates with a pressure of at least 1.2 kg/cm2 abs. or higher pressure at the top of the column. The condenser system is a steam generator that condenses the vapor into a concentrated acetic acid stream while generating a low pressure steam of 0.6-2.0 kg/cm abs.

Abstract: This invention relates to methods of replacing water and cyclohexanone with acetic acid in an aqueous solution of catalyst, preferably a cobalt compound. Such an aqueous solution is produced by extracting catalyst with water from a cyclohexanone/water solution of reaction products made by the direct oxidation of cyclohexane to adipic acid. The replacement of both water and cyclohexanone are conducted in a solvent exchange column, wherein acetic acid dissolves the catalyst, while water vapors force the cyclohexanone into a condenser, followed by a decanter wherein two liquid phases may be formed and separated; an upper liquid phase containing a majority of cyclohexanone and a lower liquid phase containing a majority of water. The cyclohexanone may be removed in a pretreatment zone, wherein also part of the water may be removed, before the concentrated catalyst extract enters the solvent exchange column.

Abstract: 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 entrainer selected from isobutyl acetate, n-propyl acetate or an entrainer with a boiling point between isobutyl acetate and n-propyl acetate.

Abstract: Reactor for containing high pressure, high temperature, corrosive reactions, especially supercritical water reactions. The reactor comprises an inner reactor vessel which houses the corrosive reaction, an outer containment vessel which contains a substantial level of the pressure, and insulating means to contain the high temperature of the inner reactor, which prevents the outer containment vessel from rising above a specified maximum temperature. Using this reactor, the lifetime and reliability of the materials of construction are increased because the outer pressure-containing vessel does not experience the high temperatures which tend to cause metals and alloys to lose ductility, and the inner reactor vessel does not experience a high pressure drop across its walls and, therefore, can be made of temperature and corrosive-resistant materials which are not required to sustain high stress without failure.

Abstract: A method for purifying acetic acid containing at least one component selected from the group consisting of unsaturated compounds and carbonyl compounds as an impurity involves the step of purifying the acetic acid with a distillation column having at least 30 plates by operating the distillation column at a pressure ranging from 40 to 760 mmHg and a reflux ratio of at least 4, and yields a high-quality acetic acid which rates high in the potassium permanganate test without needing of the addition of any chemical to the acetic acid to be purified and a large amount of energy, and is economical.

Abstract: A method of purifying the oxidate product formed by the liquid phase oxidation of C.sub.4 -C.sub.8 paraffinic hydrocarbons comprises adding a strong acid catalyst to the oxidate product to catalyze the break down of Michael addition products of unsaturated carbonyls and carboxylic acids so that the carbonyls can be distilled off during the initial stages of purification.

Abstract: Volatile acids containing metal salt impurities, such as metal pickling solutions-are regenerated by a process in which the acid is subjected to sulfuric acid distillation. Resulting volatile acid vapor is condensed and recycled to the pickle tank, while the residual acid mixture is treated in an acid sorption unit, preferably of the acid retardation type. Acid sorbed in the acid sorption unit is periodically eluted with water and recycled, while metal impurities are rejected in a deacidified by-product solution.

Abstract: 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 permeate substantially free of acid and a retentate having an acid concentration above about ten percent (10%) by weight. The retentate is contacted with a liquid extractant for acids to produce an acid-rich extractate and an acid-free raffinate. The acid is then recovered from the acid-rich extractate.

Abstract: Disclosed is a method and apparatus for recovering acetic acid from an acetic acid/water waste stream which includes a dehydration column into which the stream is fed and a liquid-liquid extraction system for recovering acetic acid from the condensate of the overhead stream of the dehydration column. Optionally, low pressure and/or high pressure absorber systems are provided to process vapor and/or liquid streams associated with the recovery system and/or the plant in which the acetic acid is used to further the recovery of acetic acid and reduce atmospheric pollution.

Abstract: Disclosed is a method and apparatus for recovering acetic acid from an acetic acid/water waste stream which includes a dehydration column into which the stream is fed and a liquid-liquid extraction system for recovering acetic acid from the condensate of the overhead stream of the dehydration column. Optionally, low pressure and/or high pressure absorber systems are provided to process vapor and/or liquid streams associated with the recovery system and/or the plant in which the acetic acid is used to further the recovery of acetic acid and reduce atmospheric pollution.

Abstract: 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 consisting essentially of mixed trialkylphosphine oxides in counter-current liquid-liquid extraction flow in a contacting step to thereby transfer the acids from the aqueous solution to the solvent, thus producing a raffinate relatively low in acid content and a rich solvent. The rich solvent is preferably dehydrated to separate water therefrom and yield a dehydrated rich solvent. The dehydrated rich solvent then has the acids stripped from it and the resulting lean solvent is then returned to the liquid-liquid extraction step, while the separated acids are split into their constituent components in a distillation operation.

Abstract: Acetic acid cannot be easily removed from acetic acid - water mixtures by distillaton because of the closeness of their boiling points and the deviation from ideal solution behavior. Acetic acid can be readily removed from the mixtures containing it and water by using extractive distillation. Typical effective agents are sulfolane and adiponitrile.

Abstract: Acetic acid is difficult to separate from water by conventional distillation or rectification because of the close proximity of their boiling points. Acetic acid can be readily separated from water by using azeotropic distillation. Typical examples of effective agents are ethyl n-valerate and 4-methyl-2-pentanone.

Abstract: An apparatus for making fresh water from salt water comprising an air accelerator for generating a controlled wind-powered vortex of air in a tower located over a supply of salt water. The vortex of air creates a region of negative pressure over the salt water which causes fresh water to migrate up the tower to a condenser whereby the fresh water is condensed and collected in a collection through to then be used as a source of drinking water.

Abstract: In this process a percolation of supercritical gas through the starting material is conducted, the carbon dioxide loading with extractable compounds, then, when the percolation pressure reaches a predetermined value, the percolation medium is let down, feeding the latter into a separation zone in which the volatile compounds are trapped in the solid carbon dioxide formed, these compounds being recovered in aqueous solution after sublimation of CO.sub.2. According to the invention, the extraction is conducted, in the separation zone, in the presence of a trapping medium suitable for retaining the volatile compounds, advantageously a medium which has very low solubility in liquid or supercritical CO.sub.2 and is capable of dissolving the volatile compounds (glycerol or edible oil) or of complexing these (cyclodextrins). The starting material chosen has a lipid content which is not excessively high (especially fruits and derived products).

Abstract: 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 water and an organic compound by using the membrane is also disclosed.

Abstract: 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 selectively removed from the gaseous mixture by permeation through an aromatic polyimide gas separation membrane while the gaseous mixture being kept in contact with a surface on one side of the gas separation membrane at a temperature of 70.degree. C. or higher to obtain a gaseous mixture comprising the organic compound vapor and a reduced amount of a water vapor.

Abstract: A process is disclosed for separating low molecular weight components from complex aqueous organic mixtures. The process includes preparing a separation solution of supercritical carbon dioxide with an effective amount of an entrainer to modify the solvation power of the supercritical carbon dioxide and extract preselected low molecular weight components. The separation solution is maintained at a temperature of at least about 70.degree. C. and a pressure of at least about 1,500 psi. The separation solution is then contacted with the organic mixtures while maintaining the temperature and pressure as above until the mixtures and solution reach equilibrium to extract the preselected low molecular weight components from the organic mixtures. Finally, the entrainer/extracted components portion of the equilibrium mixture is isolated from the separation solution.

Abstract: 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 comprises an elongated distillation column having therein a plurality of zones or stages wherein the volatile acid in the aqueous feed stream is vaporized by steam and then the vaporized acid is carried by the steam into a salt formation zone or stage to react with a reactable cation to form a salt of the acid.

Abstract: In a process for the recovery of acetic acid by extracting acetic acid from an aqueous acetic acid solution containing a metallic salt of sulfuric acid with an organic extractant comprising a tertiary amine and an organic diluent and recovering acetic acid from the liquid extract, a mixture of a tertiary amine containing sulfuric acid and an organic diluent is used as an organic extractant so as to suppress energy consumption and to increase extraction efficiency.

Abstract: Disclosed are a fluid extractant, and a process and apparatus for using the extractant to separate an organic liquid from an aqueous mixture. The extractant comprises a first fluid solvent which is a gas in its near-critical or supercritical state and a cosolvent. A preferred first fluid solvent is near-critical liquid carbon dioxide. Preferred cosolvents are 2-ethyl hexanol for ethanol extraction, and hexanoic acid for acetic acid extraction. Organic compounds such as monohydric alcohols, monoacids, ketones, ethers, aldehydes and esters can be recovered from dilute aqueous solutions more economically than possible by prior art processes of distillation.

Abstract: Acetic acid cannot be easily removed from acetic acid--water mixtures by distillation because of the closeness of their boiling points and the deviation from ideal solution behavior. Acetic acid can be readily removed from mixtures containing it and water by using extractive distillation in which the extractive distillation agent is a mono carboxylic acid, either singly or admixed with high boiling organic compounds. Typical examples of effective agents are pelargonic acid; heptanoic acid and isophorone; neodecanoic acid, acetophenone and nitrobenzene.

Abstract: Improvement in an azeotropic distillation process, the improvement being the use of an entrainer characterized in that it is an organic compound in which one or more hydrogen atoms are replaced by halogen atoms, including at least one fluorine atom; it is miscible, under process conditions, with the organic compound being dehydrated; its volatility is sufficiently close to the volatility of the organic compound being dehydrated such that, under the process conditions, it forms an azeotrope with the organic compound; it is less miscible, under process conditions, with water than is the corresponding organic compound in which the halogen atoms are replaced with hydrogen atoms; and it is chemically stable under the process conditions.

Abstract: A method for separating carboxylic acids from mixtures with non-acids by an extractive distillation method using a lactam with a 5- or 6-membered ring, preferably N-methyl-2-pyrrolidone, as an extractant to extract the acids from the mixture with non-acids, followed by separating the extracted acids from the extractant by rectification.

Abstract: A process is provided for the recovery of acetic acid from dilute aqueous solutions. The acid in the form of its calcium salt is treated with a tertiary amine carbonate and the resulting trialkylammonium acetate is isolated and heated to give the acetic acid plus a tertiary amine.

Abstract: A method of recovering or extracting chemicals, such as furfural, formic acid, acetic acid and other organic compounds from acidic hydrolysates of plants or vegetable matter, especially spent sulfite liquors after conversion of the pentosans into pentoses and then into furfural by heating the hydrolysate in an acidic environment. The conversion of the pentosans pentoses into furfural, preferably with acidulation, is accomplished in a counterflow or countercurrent flow heat exchanger and a reactor, preferably a tubular reactor. The hydrolysate which has additionally been heated and converted in the reactor is used as a heating medium or heat carrier for heating up the hydrolysate which is converted in the counterflow heat exchanger, whereupon there is recovered as the distillate furfural in conjunction with the formic acid, acetic acid and the like.

Abstract: This invention provides an improved process for the separation and recovery of byproducts associated with the isolation of C.sub.4 -C.sub.6 dicarboxylic acids contained in a waste byproduct stream derived from an adipic acid manufacturing operation involving nitric acid oxidation of a cyclohexanone/cyclohexanol feedstream.The main byproducts which are recovered are high purity dimethyl succinate, dimethyl glutarate and dimethyl adipate.

Abstract: Disclosed is a method of recovering acetic acid by extracting from an acetic acid-containing aqueous solution with an organic extracting agent and subjecting the extract to distillation, said method comprising the first step of performing extraction by using a tertiary amine having a boiling point higher than that of acetic acid and being capable of forming a non-aqueus phase as the organic extracting agent in combination with an oxygen-containing, high-boiling-point organic solvent selected from the group consisting of di-isobutylcarbinol, isophorene, methyl benzoate, tributyl phosphate, 3,3,5-trimethylcyclohexanone and 2-ethoxyethyl acetate, the second step of performing dehydration by subjecting the extract to distillation, and the third step of subjecting the dehydrated mixture to distillation in a reduced pressure distillation column at a column bottom temperature of 120.degree. to 170.degree. C. to distill acetic acid and separate it from the organic extracting agent.

Abstract: Process and apparatus for extracting an organic liquid from an organic liquid solute/solvent mixture. The mixture is contacted with a fluid extractant which is at a temperature and pressure to render the extractant a solvent for the solute but not for the solvent. The resulting fluid extract of the solute is then depressurized to give a still feed which is distilled to form still overhead vapors and liquid still bottoms. The enthalpy required to effect this distillation is provided by compressing the still overhead vapors to heat them and indirectly to heat the still feed. The process is particularly suitable for separating mixtures which form azeotropes, e.g., oxygenated hydrocarbon/water mixtures. The energy required in this process is much less than that required to separate such mixtures by conventional distillation techniques.

Abstract: C.sub.2 -C.sub.6 monocarboxylic and dicarboxylic acids are scrubbed from gas phase mixtures of such acids and water by gas absorption techniques utilizing a liquid solvent comprising a polyoxyalkylene glycol or a monoalkyl or dialkyl ether thereof. The solvent enriched with the acid is subjected to distillation to recover a substantially anhydrous acid product.

Abstract: Water is separated by distillation from organic multiple component mixtures containing at least one component partly miscible with water. The component miscible with water is distilled azeotropically with the water contained in the mixture, the distillate is separated into water and a zeotrope forming agent and the latter is recycled to the distilling column. In the recycling process, one part of the azeotrope forming agent is conducted to the top of the column and the other part is fed into the column at the feed mixture inlet or at a location thereunder.

Abstract: The separation of acrylic acid from a mixture of acrylic acid and acetic acid found in the reaction product stream obtained in the process of producing acrylic acid by the oxidation of propylene or acrolein is improved by removing a vapor sidestream from the solvent recovery column found in the process. Acetic acid is then separated from this stream without the addition of external heat.

Abstract: A lower carboxylic acid such as acetic acid is separated and recovered from an aqueous medium by the steps which include contacting, in an extraction zone, the aqueous medium with an extracting agent such as trioctyl phosphine oxide dissolved in an organic solvent such as a mixture of paraffins having a boiling range of about 160.degree. C. to 175.degree. C.

Abstract: A process is provided for purification and drying of acetic acid containing water and methyl iodide and hydrogen iodide as contaminants. The process comprises distillation in a two-zone system wherein the major part of the methyl iodide and hydrogen iodide and some water are removed as overhead and bottoms, respectively, from the first zone; a stream from the middle section of the first zone is introduced into a second zone into which there is also introduced a stream of methanol; and a stream of dry purified acid is recovered from the bottom of said second zone. The process provides both for the recovery of the iodine components and the methanol added for re-use in production of additional acetic acid by the reaction of methanol and/or methyl acetate with carbon monoxide in contact with a catalyst system formed on mixing of a rhodium or iridium component and an iodine component in the presence of carbon monoxide.

Abstract: A method is provided for removal of excess water which tends to build up in recycle streams and reduces the rate of pure acid production during operation of a distillation system for purification of crude acetic acid containing water and methyl iodide. The crude acid is introduced into the upper half of a distillation zone. The methyl iodide, a major proportion of water and an equivalent amount of acid are removed overhead from the zone. A minor proportion of the water containing a small amount of acetic acid is removed as a liquid sidedraw at a point near the top of the distillation zone. A product acid stream essentially dry and substantially free of methyl iodide is removed from the bottom of the distillation zone. The overhead stream can be stored, disposed of or preferably recycled to the acid-producing step. The liquid water sidedraw may either be discarded or subjected to rectification for recovery of acid values.

Abstract: Process for preparing technically pure acetic acid from water - acetic acid mixtures by extractive distillation with N-methyl acetamide.