Abstract: A method of recovering acrylic acid from a mixture comprising acrylic acid, water and acetic acid is disclosed, which includes: (a) extracting acrylic acid from the mixture with a solvent mixture comprising ethyl acrylate as the preponderant component thereof and an organic co-solvent selected from the group consisting of toluene, heptane, 1-heptene, methylcyclohexane, cycloheptane, cycloheptadiene, cycloheptatriene, 2,4-dimethyl-1,3 pentadiene, methylcyclohexene and methylenecyclohexene to form an extracted composition; and (b) azeotropically distilling the extracted composition to recover acrylic acid.

Abstract: A process for the separation and purification of acrylic acid is disclosed, wherein ethyl propionate is employed as an extraction solvent.

Abstract: A material contaminated with a solvent is treated with a hydrofluorocarbon to remove the contaminant. The hydrofluorocarbon can be tetrafluoroethane.

Abstract: A process for separating water from methanol in an aqueous methanol initial mixture, including subjecting said mixture to azeotropic distillation in the presence of sufficient added methyl acrylate to form an azeotrope with most of the methanol in said initial mixture such that a substantial proportion of methanol in the initial mixture is removed as an azeotrope of methanol and methyl acrylate in the overhead vapors resulting from said distillation and a major proportion of water in said initial mixture is removed in the liquid residue of said distillation.

Abstract: A process for removing impurities from 3-(2′-acetoxyethyl)dihydro-2(3H)furanone (I), where the 3-(2′-acetoxyethyl)dihydro-2(3H)furanone containing the undesirable impurities is initially prepared in a manner known per se by acetylation of 3-(2′-hydroxyethyl)dihydro-2(3H)furanone and the resulting product is subsequently subjected to a distillation or rectification, includes carrying out the distillation or rectification in a plurality of steps, where high-boiling impurities are removed in a first step, the product which is drawn off via the top is subsequently subjected to at least one further step in which low-boilers and intermediate boilers are drawn off via the top and the desired pure I is obtained as bottom product.

Abstract: A process for pretreating a oily/water stream for closed loop dilution steam production within an ethylene plant using countercurrent multi-stage extraction to remove both free and dissolved organic solutes from in-situ (net) quench water with an organic solvent to yield an aqueous raffinate containing only residual amounts of organic solute. The raffinate is steam stripped to remove the residual organic solutes, yielding a pretreated quench water stream substantially free of organic material. The pretreated quench water is suitable for reuse to generate dilution steam (without fouling). The (solvent) extract from extraction is regenerated in a solvent regenerator having an overhead stream for purging light ends, a bottom stream for purging heavy ends, and a heart-cut side stream for recycling solvent to the extractor.

Abstract: A process for the recovery and purification of cyclobutanone from a crude product mixture obtained from an oxidation product mixture resulting from the oxidation of cyclobutanol to cyclobutanone in the presence of water. The process provides for the recovery of cyclobutanone in a purity of at least 90 weight percent by a combination of distillation steps.

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 apparatus for the purification of crude N,N′-diphenyl-p-phenylenediamine (DPPD) in which there is an extraction unit containing a liquid permeable container and an adsorption layer downstream of the container, a solvent evaporator downstream of the adsorption layer, a filter unit, a line for returning the filtrate to the solvent evaporator, and a condenser for returning solvent to the extraction unit.

Abstract: An improved process for the recovery of aromatic compounds from a mixture containing aromatic and non-aromatic compounds and method for retrofitting existing equipment for the same is provided. The improved process comprises the steps of recovering aromatic compounds via parallel operation of a hybrid extractive distillation/liquid-liquid extractor operation and variations thereof. Methods of quickly and economically retrofitting existing recovery process equipment for use with the improved aromatics recovery process are also disclosed.

Abstract: The invention relates to method for separating tocopherol from a first tocopherol admixture by heating the first tocopherol admixture composed of at least one tocopherol, a fatty acid, and an esterifying compound to esterify the fatty acid to produce a second tocopherol admixture composed of the tocopherol, the esterified fatty acid, and the unesterified fatty acid; distilling the second tocopherol admixture with the esterified fatty acid to remove the unesterified fatty acid from the second tocopherol admixture to produce a third tocopherol admixture composed of the tocopherol, with substantially removed unesterified fatty acid; distilling the third tocopherol admixture for a sufficient time and temperature to substantially remove the tocopherol from the third tocopherol admixture to produce a fourth tocopherol admixture composed of the removed tocopherol and a non-tocol component; and extracting the tocopherol from the fourth tocopherol admixture with an extraction solvent composed of a polar, organic solve

Abstract: Process for the separation of hydrogen fluoride from its mixtures with a hydrofluoroalkane containing from 3 to 6 carbon atoms, by extraction using an organic solvent.

Abstract: Process for the separation of hydrogen fluoride from its mixtures with a hydrofluoroalkane containing from 3 to 6 carbon atoms, by extraction using an organic solvent.

Abstract: The invention relates to method for separating tocotrienol from a first tocol admixture by heating the first tocol admixture composed of a tocotrienol, at least one tocopherol, a fatty acid, and an esterifying compound to esterify the fatty acid to produce a second tocol admixture composed of the tocotrienol, the tocopherol, the esterified fatty acid, and the unesterified fatty acid; distilling the second tocol admixture with the esterified fatty acid to remove the unesterified fatty acid from the second tocol admixture to produce a third tocol admixture composed of the tocotrienol and the tocopherol, with substantially removed unesterified fatty acid; distilling the third tocol admixture for a sufficient time and temperature to substantially remove the tocotrienol and tocopherol from the third tocol admixture to produce a fourth tocol admixture composed of the removed tocotrienol, tocopherol, and a non-tocol component; and extracting the tocotrienol from the fourth tocol admixture with an extraction solvent

Abstract: The invention relates to method for separating tocol from a tocol-containing admixture by heating the tocol-containing admixture composed a tocol, a fatty acid, and an esterifying compound to esterify the fatty acid to produce a second tocol admixture composed of the tocol, the esterified fatty acid, and the unesterified fatty acid; distilling the tocol-containing admixture with the esterified fatty acid to remove the unesterified fatty acid from the tocol admixture to produce a tocol admixture composed of the tocol with substantially removed unesterified fatty acid; distilling the tocol admixture for a sufficient time and temperature to substantially remove the tocol from the tocol admixture to produce a tocol admixture composed of the removed tocol and a non-tocol component; and extracting the tocol from the tocol admixture with an extraction solvent composed of a polar, organic solvent that is miscible with water to produce a two phase system composed of a first phase containing the majority of the extract

Abstract: The invention relates to a 3-step process for removing water-soluble organics from waste streams. The first step involves contacting a waste stream with base, the second step involves contacting the organics-containing water with free oil and finally the free oil phase is separated from the aqueous phase to produce substantially organic-free water.

Abstract: A process for the separation of propylene from an input stream of C3 hydrocarbons containing propylene and methyl acetylene and/or propadiene and, optionally, C4 and/or higher hydrocarbons is described. The process includes subjecting the input stream to fractional distillation to separate propylene as an overhead stream leaving a bottoms stream containing the methyl acetylene and/or propadiene and the C4 and/or higher hydrocarbons, when present. A propane-containing stream is added to said input stream whereby propane is separated as part of the bottoms stream. The propylene content of the bottoms streams is maintained at less than 10% weight. The amount of propane added to the input stream is such that the weight of propane, propylene, and C4 and/or higher hydrocarbons, when present, in the bottoms stream is greater that the total weight of methyl acetylene and propadiene in the bottoms stream.

Abstract: A solvent extraction apparatus which includes a heating plate, a vessel for containing a solvent, an extraction thimble to obtain a sample to be extracted from said vessel and a cooler for condensing evaporated solvent vapors. The cooler is connected to the vessel for containing the solvent, preferably by an adaptor. A lifting rod is provided which passes through the cooler which, at its lower portion, is provided with a drip rim on which the extraction thimble is detachably fixed. The thimble can be moved vertically by the lifting rod and the flow of solvent into and out of the cooler can be regulated by the lifting rod.

Abstract: A process for separating a multi-component mixture containing solid or liquid organic components by treating the mixture with a gaseous entraining agent comprising a superheated carrier fluid containing a lower monohydric alcohol or a lower monohydric alcohol and water to cause constituents of the multi-component mixture to become entrained in the gaseous entraining agent, and separating the gaseous entraining agent containing constituents of the multi-component mixture from the multi-component mixture.

Abstract: Highly purified HCl for use in semiconductor manufacturing is prepared on-site by drawing HCl vapor from a liquid HCl reservoir, and scrubbing the filtered vapor in a low-pH aqueous scrubber.

Abstract: The disclosure relates to separating 1,1,1-trifluoroethane (HFC-143a from fluorocarbon impurities by using extractive distillation with an extractive agent comprising an alcohol. Examples of suitable extractive agents comprise at least one member from the group of methanol, butanol, ethanol, propanol, their isomers and cyclic compounds thereof, among others.

Abstract: A method for continuously extracting a solute from a carrier medium. A volatile solvent is placed in a lower distillation chamber of a vessel, the vessel including a convergent baffle disposed to separate the vessel into a lower distillation chamber and an upper extraction chamber. The convergent baffle is contoured to converge to define a conduit riser projecting upwardly into the extraction chamber and terminating in a vaporized solvent port placing the distillation chamber in fluid flow communication with the extraction chamber. A carrier medium containing a solute to be extracted is placed in the extraction chamber. The volatile solvent in the distillation chamber is then vaporized. The vaporized solvent flows upwardly and is converged through the convergent baffle and conduit riser. The converged vapor stream passes through the vaporized solvent port into the carrier medium, flowing through the carrier medium and inducing a linear-torroidal flow in the carrier medium.

Abstract: In a method for the extraction treatment of a sample (19) with a solvent which is liquid at normal ambient temperature and normal pressure, in which the solvent is introduced into a preferably heatable sample chamber (12a) and there brought into contact with the sample (19), in which the solvent vapour arising in the sample chamber (12a,26) is drawn off out of the sample chamber in such a manner that an under-pressure arises in the sample chamber and a further part of the liquid solvent passes into the vapour phase, and in which the drawn off solvent vapour is cooled outside the sample chamber (12a,26) and thereby, for the purpose of recovery of pure solvent, is at least partially passed back into the liquid phase, the drawn-off solvent vapour is additionally subjected to over-pressure.

Abstract: The invention relates to a process for the preparation of acesulfam salts by reaction of salts of amidosulfonic acid with diketene to give a salt of acetoacetamidosulfonic acid (I), ring closure by the action of at least about an equivalent amount of SO.sub.3, at least this ring closure reaction being carried out in the presence of a halogenated, aliphatic hydrocarbon as an inert solvent, treatment of the cyclization product with water and conversion of the resulting acesulfam-H (II) into the form of a non-toxic salt, which comprises, in the work-up by distillation of the resulting crude solvent, after removal of water and low-boilers and recovery of solvent sufficiently pure for reuse in the preparation of compounds (I) and/or (II), directly returning :he remaining, solvent-containing distillation residue, without further purification, into the system downstream of the reaction vessel for carrying out the ring closure reaction.

Abstract: A method of processing a test sample to concentrate an analyte in the sample from a solvent in the sample includes: a) boiling the test sample containing the analyte and solvent in a boiling chamber to a temperature greater than or equal to the solvent boiling temperature and less than the analyte boiling temperature to form a rising sample vapor mixture; b) passing the sample vapor mixture from the boiling chamber to an elongated primary separation tube, the separation tube having internal sidewalls and a longitudinal axis, the longitudinal axis being angled between vertical and horizontal and thus having an upper region and a lower region; c) collecting the physically transported liquid analyte on the internal sidewalls of the separation tube; and d) flowing the collected analyte along the angled internal sidewalls of the separation tube to and pass the separation tube lower region.

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: An apparatus (10) for continuously extracting a solute from a carrier medium (102) is provided. The apparatus is formed from a vessel (12) including a convergent baffle (22) separating the vessel into a lower distillation chamber (24) and an upper extraction chamber (26). The convergent baffle is configured as an inverted funnel such that it defines a conduit riser (28) projecting upwardly into the extraction chamber and terminating in a vaporized solvent port (30) placing the distillation chamber in fluid-flow direct communication with the extraction chamber. A vapor rotating spheres-condenser (34) is mounted on the upper end of the vessel and opens into the extraction chamber. Solvent is placed in the distillation chamber while the carrier medium containing the solute is placed in the extraction chamber. Solvent is vaporized in the distillation chamber, rises upwardly through the conduit riser, and passes through the carrier medium, thereby extracting solute in a continuous linear-toroidal motion.

Abstract: The method of cleaning soil contaminated with contaminants includes comminuting contaminated soil to form a comminuted contaminated soil; filling the comminuted contaminated soil into a countercurrent extractor from above under an inert gas atmosphere so that the comminuted contaminated soil moves as a travelling bed downward through the countercurrent extractor; feeding a solvent, advantageously acetone, into a lower portion of the countercurrent extractor so that the solvent flows upward through the travelling bed to form a decontaminated soil at the bottom of the extractor and a contaminant-charged solvent portion taken from a middle portion; supplying a conveying liquid to the lower portion of the countercurrent extractor so as to transfer the decontaminated soil from the countercurrent extractor to a filter device having a belt filter; and separating the decontaminated soil in the filter device into a cleaned soil and a reusable conveying liquid.

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: A method of continuously distilling off the components of a mixture containing phenols, water and methanol using a single distillation column, wherein methanol is recovered from the top of the column, water containing phenols is dragged as a side stream from a recovery section of the column, and phenols are recovered as a bottom product. The method permits efficient separation by the single distillation column of the three components with high purity and low utility energy.

Abstract: This invention provides a process for producing crystalline hydroxyacetaldehyde precipitated from a complex mixture of products provided by the pyrolysis of a carbohydrate-containing feedstock. The method includes distilling a first condensate under reduced pressure to give a second condensate which is enriched in hydroxyacetaldehyde; combining the second condensate with a solvent to give a homogeneous solution; precipitating hydroxyacetaldehyde from the solution; and separating the precipitated hydroxyacetaldehyde from the solution.Aqueous solutions of hydroxyacetaldehyde are useful for browning foodstuffs and for producing flavors by contacting the hydroxyacetaldehyde with ammonia or amines.In addition, hydroxyacetaldehyde may be used to make an artificial tanning product containing a suitable topical vehicle and an amount of hydroxyacetaldehyde suitable to impart a brown color to skin.

Abstract: A process is provided for separating high purity alkyl glycolate from a gaseous reaction mixture resulting from the catalyzed gas phase oxidation of alkyl glycolate. A hot solvent which is immiscible with water but selectively dissolves alkyl glycolate and alkyl glyoxylate is brought in contact with the gaseous reaction mixture, and water and alcohol vapors are removed from the hot solvent. The alkyl glyoxylate is removed from the solution by a first distillation and the alkyl glycolate and solvent are then separated in a second distillation.

Abstract: The present invention provides an apparatus for preparing and treating a heavy oil extraction solvent. A solvent fraction is separated from a crude oil and combined with a slip stream of rerun solvent taken from an extraction process solvent recycle system. The solvent fraction and rerun solvent are fractionated to provide a purified extraction solvent. The purified extraction solvent is then utilized in the heavy oil extraction process.

Abstract: A method for recovering a liquid diluent having a low salt content from an organic/aqueous mixture which contains significant quantities of the diluent, an alkali metal salt, and water comprises an integrated process which joins extraction and ion exchange steps and a reaction for the conversion of an alkali metal hydroxide. In the initial step the diluent is extracted from the original mixture employing a suitable extractant material. The extract from the initial step containing diluent, extractant material, along with reduced quantities of water and salt, is passed to an ion exchange column for conversion of the alkali metal salt to its hydroxide. In a following fractional distillation dewatering column the diluent begins to react with the alkali metal hydroxide to form an alkali-metal salt of aminocarboxylic acid which can pass harmlessly through the dewatering column for removal in further following fractional distillation step.

Abstract: In the diisopropyl ether production process, the distallation step for the separation of aqueous IPA recovered from the DIPE extraction operations is modified to avoid carrying out the distillation under conditions that yield IPA-water azeotrope providing lower overall process cost. The determination has been made that the overhead and bottom streams form an aqueous IPA fractionation process operated under off-azeotrope conditions in DIPE production can be recycled, respectively, to the DIPE reactor and extractor operations. Recycling the water and IPA overhead mixture eliminates the requirement for adding fresh water to the DIPE reactor. Returning the water and IPA bottom stream to the extractor reduces the requirement for distilled water addition to the extraction step. As a consequence, a less complex and costly aqueous IPA separation process is implemented.

Abstract: A process for removing dimethyl ether (DME) and methanol impurities from C.sub.4 hydrocarbon stream without substantial loss of C.sub.4 hydrocarbons by fractionating a C.sub.4 hydrocarbon stream containing DME and methanol at low levels, e.g., less than 5 wt. % to produce an overhead of about 20 to 40 volume % of the C.sub.4 stream, condensing the overhead, contacting the condensed overhead with about 1 to 5 volumes of water, thereby removing a portion of the DME and methanol from the C.sub.4 stream, returning substantially all of the C.sub.4 stream, except the small amount solubilized in the water, to the fractionation and flashing the solubilized DME and hydrocarbons from the water. The fractionation and extraction are preferably carried out at elevated pressures, e.g., 200 to 300 psig to avoid refrigeration of the overhead condensation. The flashing of the DME and hydrocarbons is carried out by reducing the pressure on the water, e.g. atmospheric pressure at a temperature in the range of 20.degree. C.

Abstract: Carboxylic acids are recovered from wet organic solutions by reducing the solutions' water content thus causing the acids to precipitate as recoverable crystals.

Abstract: Apparatus for the manufacture and recovery of alkali-metal tetraorganylborates. A mixed solvent and liquid/liquid contactor configuration is used in the system which aids in the recovery of the product.

Abstract: High purity isopropyl acetate and ethanol are recovered from a process stream containing isopropyl acetate, ethanol and water by a multiple step process including extracting substantially all of the ethanol from the stream using water as a solvent, stripping the extract stream to remove substantially all of the remaining isopropyl acetate as an overhead recycle stream, which is combined with the fresh feed stream prior to the extraction step, fractionating the ethanol-rich stripping column bottoms stream to produce a ethanol-water azeotropic overhead stream and using a portion of the fractionating column bottoms stream as the solvent for the extraction step.

Abstract: The purpose of the process of the present invention is to remove excess sulfuric acid from a mixture of paraffin-sulfonic acids free or substantially free, from paraffins.In order to remove said sulfuric acid, according to the process of the present invention, the paraffin-sulfonic acid mixture is mixed with one or more halogenated solvent(s), possibly in mixture with sulfuric acid to form a two phase mixture consisting of an organic phase containing paraffin-sulfonic acids dissolved therein and an aqueous phase substantially containing sulfuric acid. The organic phase is then treated with sulfuric acid and the organic phase and aqueous phase are then separated and the organic phase is submitted to evaporation, for the removal of the halogenated solvent(s), and with the concentrated paraffin-sulfonic acids being obtained.

Abstract: The invention relates to a gentle process for the separation of enol ethers from mixtures containing water-soluble alcohols by extraction, wherein an aqueous solution of a base is used as the extraction agent in a phase ratio of the amounts of the aqueous phase: enol ether/alcohol mixture of at least 0.5:1 and the extraction is carried out in several stages or continuously with a theoretical number of stages of at least two. The process is particularly suitable for separating off enol ethers which readily decompose during distillation.

Abstract: In the method for the production of an aromate concentrate suitable for use as blending component for gasifier fuel, feed hydrocarbon mixtures having boiling ranges substantially between 40.degree. and 170.degree. C., are subjected, without any previous separation into individual fractions, to an extractive distillation employing N-substituted morpholine, substituents of which display no more than seven C-atoms, as selective solvent. Herewith, the lower boiling non-aromates with a boiling range up to about 105.degree. C., practically completely, and most of the higher boiling non-aromates with a boiling range between about 105.degree. and 160.degree. C., are recovered as raffinate, whereas the aromates, which are to be employed in whole or in part as blending component, come down in the extract of the extractive distillation.

Abstract: Primary and secondary hydroperoxide contaminants in a tertiary hydroperoxide composition obtained by oxidation of a branched hydrocarbon are removed by contacting the tertiary hydroperoxide with a carboxylic acid derivative such as an anhydride and a basic compound such as sodium hydroxide. A tertiary hydroperoxide such as tertiary butyl hydroperoxide is purified with minimal loss of the desired tertiary hydroperoxide.

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: A method of producing a potable spirit comprises removing water from a fermented wash containing ethanol, water and congeners to produce a substantially water-free mixture of ethanol and congeners, and then fractionally distilling this water-free mixture of ethanol and congeners in the absence of water to produce a fraction containing substantially pure water-free potable ethanol. Preferably the fractional distillation is carried out in separate topping and tailing columns. This method provides an energy efficient separation of the ethanol and congeners.

Abstract: This invention relates to a method for separating organic compounds, particularly lower aliphatic alcohols from fermentation fluids. This is accomplished by the use of a two-step extraction process whereby said lower aliphatic alcohols are selectively extracted from said fermentation fluids by a first solvent. The fermentation fluids from which the lower aliphatic alcohols have been extracted contain some of this first solvent. Therefore, a second solvent, which substantially differs from the first solvent in polarity is employed to extract the residual amounts of first solvent from said fermentation fluids. Then, the fermentation fluids, thus purified, can be returned to the fermentation process without the danger of toxic influences on the fermentation by the presence of said first solvent.

Abstract: A process for extracting poly-beta-hydroxybutyrates from an aqueous suspension of microorganisms, in which an azeotropic distillation, and an extraction of the polymer by means of the solvent used, are carried out simultaneously.The poly-beta-hydroxybutyrates obtained can be used in medicine.

Abstract: A method and apparatus for producing a product which stimulates skin respiration and product produced thereby are provided wherein the method comprises the steps of mixing bakers yeast and alcohol in an extractor to produce a slurry of solids and liquid, heating the slurry to a predetermined temperature to produce a heated slurry, holding the heated slurry at the predetermined temperature for a predetermined time, passing the heated slurry through a filter to remove the solids and produce a filtered liquid, placing the filtered liquid in a sterile vacuum still and boiling the filtered liquid in said vacuum still to drive off a substantial percentage of the liquid therein and produce the product, and then further filtering the product in a closed pressure filtering system followed by filtering of the further filtered product through a sterile filter.

Abstract: The invention relates to a process for separating dimethyl isophthalate (DMI) and dimethyl orthophthalate (DMO) and other by-products from their mixture with dimethyl terephthalate (DMT), formed in the oxidation of p-xylene followed by esterification with methanol, by crystallization from the melt.Initially, the esterification product is here distilled once or several times. The DMT-rich fraction obtained is then subjected wholly or partially to one or several crystallizations from the melt, and the DMI-DMO fraction thus obtained is at least partially removed from the system. As an alternative, the DMT-rich fraction is first recrystallized from methanol, the methanol is then evaporated from the mother liquor and the remaining residue is subjected to one or several crystallizations from the melt. The DMI-DMO fraction thus obtained is again at least partially removed from the system.

Abstract: High purity isopropyl acetate and ethanol are recovered from a process stream containing isopropyl acetate, ethanol and water by a multiple step process including extracting substantially all of the ethanol from the stream using water as a solvent, stripping the extract stream to remove substantially all of the remaining isopropyl acetate as an overhead recycle stream, which is combined with the fresh feed stream prior to the extraction step, fractionating the ethanol-rich stripping column bottoms stream to produce a ethanol-water azeotropic overhead stream and using a portion of the fractionating column bottoms stream as the solvent for the extraction step.