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: Process for isolating dimethyl 4,4'-biphenyldicarboxylate from residues of DMT production, which includes first distilling the residues at a pressure of at most 7 mbar at a boiler temperature from 200.degree. to 350.degree. C., subsequently treating the distillate which distills over in the range from 230.degree. to 270.degree. C. at a pressure of, for example, 0.2 mbar for from 10 to 60 minutes with 0.7 to 10 times the amount of an organic solvent at a temperature from 70.degree. to 180.degree. C., if required, separating the clear solution from undissolved components, cooling the removed clear solution to a temperature from 45.degree. to 65.degree. C. and allowing it to crystallize at this temperature, resulting in a suspension of dimethyl 4,4'-biphenyldicarboxylate crystals from which the crystals are isolated by washing one or more times with the same or a different solvent and by drying.

Abstract: Phenol plant waste water containing small amounts of phenol and sodium sulfate is successfully distilled through the addition of recovered sodium sulfate to enhance the volatility of the phenol relative to water; at least a portion of the sodium sulfate is recycled, while a significant portion of the phenol can be returned to the phenol plant for recovery.

Abstract: A method of regenerating an etching waste fluid, includes the steps of dissolving HCl gas in an etching waste fluid at a temperature falling within a range of 20.degree. C. to 50.degree. C. and crystallizing NiCl.sub.2 and FeCl.sub.2 crystals, the etching waste fluid containing NiCl.sub.2, FeCl.sub.3, and FeCl.sub.2 and being obtained by etching Ni or an Ni alloy with an etching solution consisting of an aqueous solution containing FeCl.sub.3, distilling a mother liquor at the atmospheric pressure after crystallization and separation thereof to reduce the HCl concentration in the mother liquor, and distilling, at a reduced pressure, a concentrate obtained upon distillation at the atmospheric pressure to further reduce the HCl concentration, thereby obtaining an aqueous solution containing FeCl.sub.

Abstract: Organopolysiloxane powder is prepared from an organopolysiloxane solution by admitting the organopolysiloxane solution into a planetary-screw mixer and agitating the solution at a sufficient temperature to allow a low-boiling liquid component to evaporate from the solution, thereby separating the low-boiling liquid component from the solution.

Abstract: 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.

Abstract: 2-(4-Isobutylphenyl)-propionic acid is purified by subjecting it to a vacuum rectification, in which the temperature is below the decomposition temperature of the acid.

Abstract: A process for the production of tocopherols (T) and tocotrienols (T3) from palm fatty acid distillates (PFAD). The process includes converting free fatty acids and glycerides in PFAD into alkyl esters, then separating T and T3 from the alkyl esters and other impurities. The T and T3 are concentrated by ion-exchange and further concentrated by distilling the resulting product. Specific catalysts and optimum temperatures for the process are included. The resulting purified tocopherols and tocotrienols are useful substances, exhibiting antioxidant and physiological activities.

Abstract: A process for separating m- and p-dichlorobenzene by extractive rectification with an extractant and removal of this extractant. Using as extractant an alkylene carbonate of the formula ##STR1## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are identical to or different from one another and each is hydrogen, methyl or ethyl, with the proviso that together the radicals R.sup.1 to R.sup.4 do not contain more than 6 carbon atoms.The process of the invention makes it possible to separate off the m-isomer in high purity.

Abstract: In the process for the purification of diemthyl terephthalate (DMT) by recrystallization from methanolic solution, the mother liquor containing the impurities, substantially the isomers DMI, DMO and aldehydes, is separated off and passed to a workup tank. The moist crystals are dried by melting with the evaporation of methanol. The mother liquor is then separated off by filtration, and the moist crystals obtained from the separation are washed before melting. The washing liquid is recycled together with a portion of the separated mother liquor into the recrystallization tank.

Abstract: A method of separating and purifying a spent solvent generated in a nuclear fuel cycle and containing a phosphate and a higher hydrocarbon. This method comprises treating the spent solvent at a temperature not greater than the freezing point of the higher hydrocarbon but not less than the freezing point of the phosphate to selectively freeze the higher hydrocarbon, and separating a resulting frozen solid mainly composed of the higher hydrocarbon from a remaining solution containing the phosphate in a higher concentration. The remaining solution may further be subjected to low-temperature vacuum distillation to separate the solution into the phosphate and a deterioration product thereof.

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: A purified desired isomer which is either 3,4- or 3,5-dimethylphenol is separated with a high yield from a dimethylphenol-containing fraction which contains both 3,4- and 3,5-dimethylphenols. The fraction is distilled so as to give a distillate which is enriched with the desired dimethylphenol isomer to be separated and which contains at least 35% by weight of the desired isomer. The desired DMP isomer is crystallized from a melt of the enriched distillate in two stages with at least part of the filtrate separated from the precipitated crystals in the second crystallization stage being circulated to the first crystallization stage. The enriched distillate is introduced into the first crystallization stage when it contains the desired isomer in a concentration of from 35% to less than 70% by weight, or it is introduced into the second crystallization stage when it contains the desired isomer in a concentration of 70% by weight or higher.

Abstract: A process for producing, from a dilute aqueous solution of a lower (C.sub.1 -C.sub.5) alcohol, a concentrated liquid solution of the alcohol in an aromatic organic solvent is disclosed. Most of the water is removed from the dilute aqueous solution of alcohol by chilling sufficiently to form ice crystals. Simultaneously, the remaining liquid is extracted at substantially the same low temperature with a liquid organic solvent that is substantially immiscible in aqueous liquids and has an affinity for the alcohol at that temperature, causing the alcohol to transfer to the organic phase. After separating the organic liquid from the ice crystals, the organic liquid can be distilled to enrich the concentration of alcohol therein. Ethanol so separated from water and concentrated in an organic solvent such as toluene is useful as an anti-knock additive for gasoline.

Abstract: An apparatus including an evaporator, a pre-crystallizer, a spray dryer and a fluid bed for drying whey and a rotating disc having a cone-shaped upper surface is provided for receiving partially dried whey from the spray dryer and delivering the whey to the fluid bed while permitting crystallization of the whey as it rests on the surface of the disc.

Abstract: A process for the separation of ortho-, meta- and para-tolunitrile from ternary mixtures of isomers entails removing ortho-tolunitrile from these mixtures by distillation under pressures of from 10.sup.2 and 10.sup.5 Pa and with a reflux ratio of from 1:1 to 200:1, and distilling the remaining binary mixture of meta- and para-tolunitrile to concentrate to more than 75 mol-% para-tolunitrile, and freezing out the paratolunitrile at below 26.degree. C., and a process for the preparation of suitable ternary mixtures of isomers entails isomerization of pure ortho-, meta- or para-tolunitrile or mixtures thereof at from 380.degree. to 580.degree. C. on zeolite catalysts.

Abstract: A process for obtaining available elements from seawater is described, which process includes two separation steps. The first separation step involved adjusting the pH of seawater to a low pH by adding a strong acid having sulphate ion, adding a strongly alkaline agent thereto in amount sufficient to provide a high pH and separating the precipitate formed thereby from the filtrate. The second separation step involves concentrating the filtrate, cooling the concentrated filtrate and separating a precipitate thereby formed. Each precipitate and each filtrate obtained in these steps has characteristic components and can be utilized for many purposes, for example, for food additives, as a solvent for paint, as combustion aids, or as alkaline agents for neutralization etc.

Abstract: Water-insoluble crystallizable epoxy alcohols such as phenyl glycidol are recovered from epoxidation reaction mixtures by washing the mixture with water, concentrating the mixture by distillation under vacuum to remove unreacted hydroperoxide and alcohol co-product, and crystallizing the epoxy alcohol from solution. Minimal decomposition of the epoxy alcohol is observed.

Abstract: This invention relates to a process for producing an olefin product having an enhanced alpha olefin content from an olefin feedstock containing internal olefins or a mixture of internal and alpha olefins which includes:(a) contacting the feedstock with an anthracene and a double-bond isomerization catalyst at a temperature ranging from about 150.degree. to about 275.degree. C. to form an olefin adduct with anthracene,(b) separating the adduct from the product of step (a),(c) heating the separated adduct at a temperature ranging from about 250.degree. to about 400.degree. C. to produce anthracene and an olefin product enhanced in alpha olefin content over the alpha olefin content of the feedstock, and(d) separating anthracene from the product of step (c) to produce the product enhanced in alpha olefin.Linear olefins are a preferred feedstock.

Abstract: At the production of alkali metal chlorate by electrolysis of alkali metal chloride in an electrolyser a part of the liquid phase from the electrolyser is brought to a crystallizer for precipitation of alkali metal chlorate crystals. The hydrogen gas formed in the electrolyser is purified from contamination of chlorine gas by contacting it with the outgoing mother liquor from the crystallizer, which has a pH in the interval 7.5 to 14. The mother liquor is then brought back to the electrolysis system.

Abstract: Isomer mixtures of 1,3- and 1,4-bis-(2-hydroxyhexafluoroprop-2-yl)-benzene are separated by a steam distillation in the presence of CS.sub.2. On cooling of the steam distillate, a solid precipitates which is composed mainly of the 1,4-isomer. After the solid has been separated off, an aqueous-organic liquid-phase mixture remains, the organic phase of which mainly contains the 1,3-isomer. The pure isomers are obtained by recrystallization or distillation respectively. These are mainly intermediates in the polymer field.

Abstract: This invention is a method of purifying crude caprolactam. The improved method comprises taking a portion of a process stream of crude caprolactam having low boiling impurities and distilling the stream in the presence of water by fractional distillation into an overhead containing water and low boiling impurities and bottoms of caprolactam having improved purity and low water content.The improvement also comprises taking a low water content stream of crude caprolactam having low boiling impurities and adding water to the stream and distilling the stream by fractional distillation as described above.

Abstract: A process for distillation-crystallization of a zinc carbonate which is characterized in that a distillation column having a plurality of plates or trays is used for crystallizing basic zinc carbonate (2ZnCO.sub.3.3Zn(OH).sub.2 or ZnCO.sub.3.3Zn(OH).sub.2 H.sub.2 O) from a solution of basic zinc ammonium carbonate (Zn(NH.sub.3).sub.4 CO.sub.3); said solution is fed to an upper portion of the distillation column, while heating a bottom portion of the distillation column, to effect a distillation operation.

Abstract: A continuous process and apparatus for drying aqueous solids by evaporation using a fluidizing oil and a surfactant wherein the fluidizing oil and surfactant are recovered and recycled separately or together. The aqueous solids may, or may not, have a heavy, natural oil associated with them.

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: A continuous process and apparatus for drying aqueous solids by evaporation using a fluidizing oil and a surfactant wherein the fluidizing oil and surfactant are recovered and recycled separately or together. The aqueous solids may, or may not, have a heavy, natural oil associated with them.

Abstract: Separation and recovery of dibenzofuran of high purity is accomplished by distilling a coal tar fraction having boiling point range of 220.degree. to 300.degree. C. thereby producing a dibenzofuran fraction having a dibenzofuran content of not less than 30% by weight, a dibenzofuran/acenaphthene molar ratio of not less than 1.3, and a fluorene/dibenzofuran molar ratio of not more than 0.05, then introducing the dibenzofuran fraction obtained as described above into a continuous crystallization purification unit provided with a cooling zone for crystallization of the feed, a heating zone for melting the purified crystals, and a refining zone for enabling crystals being transferred from said cooling zone to said heating zone to come into counter current contact with a mass of molten crystals midway along the path between said two zones, and subjecting the dibenzofuran fraction to continuous crystallization purification therein.

Abstract: A process for the production of a crude dimethyl terephthalate suitable for hydrolyzing into a fiber grade terephthalic acid involves separating a crude ester obtained from the production of dimethyl terephthalate by the Witten process by vacuum distillation at elevated pressure in a three-column series arranged distillation system. In the first distillation column of the system the crude is separated into a methyl p-toluate-rich fraction as head product; in a second column of the series, into a fraction rich in methyl ester of terephthalaldehydic acid as head product; and in a third distillation column, a crude dimethyl terephthalate fraction. The crude dimethyl terephthalate fraction has a methyl ester of terephthalaldehydic acid content of 0.01-0.1% by weight as a head product.

Abstract: An improved process for recovering high purity resorcinol produced by the rearrangement of m-diisopropylbenzene dihydroperoxide in which the rearranged product mixture is neutralized, the neutralized mixture being filtered, the filtrate being admixed with toluene, the acetone being removed by distillation and the acetone-free rearranged product/toluene mixture being steam distilled to provide an aqueous resorcinol containing phase from which the resorcinol is recovered.

Abstract: A process for the separation of a dissolved solid from an aqueous solution containing it, comprising the steps of (a) adding thereto an organic liquid which is a poor solvent for the dissolved solid and which forms an azeotrope with water, (b) subjecting the mixture to azeotropic distillation to separate at least a major portion of the water, (c) cooling the mixture thereby causing substantially complete separation of the dissolved solids, and (d) separating same from the mother liquor.

Abstract: A method of separating acids or bases from vapors which are conveyed along with distillation vapors during concentration of a solution, comprising, passing said distillation vapors containing an acid or base, while being maintained at their existing pressure and temperature, through a salt solution which boils at said temperature and pressure, wherein, if an acid is to be removed from the distillation vapors, the salt solution contains a salt having an anion corresponding to that of the acid while being supplied with a base in an amount required to neutralize the acid, the cation of the base proportion corresponding to that of the salt, while, if a base is to be removed from the distillation vapors, the salt solution contains a salt having a cation corresponding to that of the base while being supplied with an acid in an amount required to neutralize the base in the distillation vapors, the anion of the acid corresponding to that of the salt so that salts are formed during neutralization which correspond to t

Abstract: Highly decolorized, purified hydroquinone and resorcinol can be separated from each other from a mixture containing hydroquinone and resorcinol and recovered by continuously rectifying the mixture, thereby obtaining rectification bottoms containing resorcinol and hydroquinone in a ratio by weight of resorcinol to hydroquinone of 0.1-1:1 while obtaining resorcinol as a distillate, redistilling the rectification bottoms, contacting hydroquinone vapor with water vapor, condensing the hydroquinone vapor in the presence of the water vapor, thereby recovering hydroquinone as an aqueous hydroquinone solution, and then recrystallizing the aqueous hydroquinone solution, if necessary, in the presence of an organic solvent, thereby separating hydroquinone from the aqueous solution.

Abstract: A process for separating ortho-, meta-, and/or para-dichlorobenzene from an isomeric mixture thereof which comprises:A. in a first step, distilling said isomeric mixture to distill over meta- and/or para-dichlorobenzene to leave behind ortho-dichlorobenzene which is separated off as bottoms product;B. in a second step, cooling the distillate from step A to a temperature of 10.degree. to 40.degree. C. whereby para-dichlorobenzene as a solid phase is obtained and separating said solid phase from liquid phase with which it is in admixture;C. in a third step, further cooling said liquid phase from step B to a temperature of -40.degree. to -5.degree. C. whereby to precipitate a second solid phase and separating said second solid phase from the liquid phase with which it is in admixture;D. in a fourth step, distilling the liquid phase from step C whereby to obtain an isomeric mixture as bottoms and an isomeric mixture as distillate; andE. removing m-dichlorobenzene from the distillate of step D.

Abstract: Wheat germ oil is treated by degumming with phosphoric acid and water, bleaching with activated clay and distilled in a centrifugal molecular still at 140.degree.-200.degree. C. at pressures below 50 milli-torr. The free fatty acids which are removed by the distillation step may be recovered as valuable by-products. The phospholipids removed in the degumming step may be recovered as valuable by-products. A vitamin E concentrate may be prepared by further distilling the purified wheat germ oil at 220.degree.-300.degree. C. at pressures below 25 milli-torr.

Abstract: 2,2-Dichloro-5-methyl-1,1,1-trifluorohex-4-ene, an intermediate in the synthesis of pyrethroid insecticides, is obtained by continuous distillation, preferably under sub-atmospheric pressure, of a mixture of 5-methyl-2,2,4-trichloro-1,1,1-trifluorohexane, dimethylformamide and lithium bromide, precipitating the chlorofluorocarbons from the distillate with water and separating the desired product from starting material by a further distillation.

Abstract: Excessive energy consumption of a combination of multi-fractionations and multi-distillations of concentrating aqueous acetic acid product of liquid phase oxidations, especially oxidation of liquid n-butane with oxygen gas while the butane is dissolved in liquid acetic acid containing a catalyst system comprising Co-Br or Co-Mn-Br, is avoided and an otherwise hard to remove bromo-ketone is readily removed by a combination of sequential steps of decompressing the oxidation reaction mixture to remove unreacted butane as well as gaseous products, heat treating the decompressed liquid at a temperature of from 150.degree. C. up to 200.degree. C. for from 15 up to 150 minutes, subjecting the heat treated liquid to fractionation while recycling to the rectification zone thereof an aqueous portion of low boiling impurities as a means for concentrating the acetic acid and thereafter further concentrating the acetic acid produced by continuous fractional crystallization.

Abstract: Minerals are recovered from warm geothermal brines by installing a brine eductor device such as a venturi at the end of a thermally insulated drill casing. The geothermal brine is recovered by flowing a warm, low saline carrier solution at high flow rate through the device to pick up a selected flow of brine. On entering the device the geothermal brine is diluted in an amount sufficient to preclude precipitation and scaling as the mixture flows to the surface. The flow velocity is adequate to entrain any non-dissolved solids without settlement. Thermal losses to the surrounding strata are minimized by the thermal insulation surrounding the casing. The mineral values are recovered from the mixture by flashing, evaporation, and filtration. Clarified solution, filter liquor and make-up water as necessary are combined to form the low salinity carrier solution which is heated in heat exchangers before recycling to the eductor device.

Abstract: Alkane dicarboxylic acids of at least 4 carbon atoms particularly the mixture of succinic, glutaric and adipic acids obtained as byproduct in the manufacture of adipic acid are purified by co-distillation with an alkylbenzene having an atmospheric pressure boiling point of 300.degree. to 350.degree. C. especially dodecylbenzene.

Abstract: In pickling metal, such as iron, steel, special alloys, or the like, aqueous blends containing hydrofluoric acid and nitric acid are used as pickling solutions; resulting spent pickling solutions are evaporated under controlled conditions, such that the concentrate is supersaturated and contains a predetermined amount of iron; the concentrate is then partially cooled and transferred to a crystallization zone where, under controlled conditions, a crystalline precepitate is formed by cooling the concentrate in two phases; the resulting precipitate is then separated from its mother liquor, and the latter is recycled for use in pickling metals of the aforedescribed type.

Abstract: The purification of high-melting organic products, such an anthraquinone and substituted anthraquinones, which is substantially free from lower-boiling impurities, by melting the product to be purified by heating, while mechanically conveying the same along a path with a screw conveyer, as for example, in a melting screw; degassing the melt at a reduced pressure in a column, as for example, at a pressure of 50 to 400 mm Hg; passing the degassed melt through a thin film evaporator at a reduced pressure of, for example, 5 to 250 mm Hg to evaporate the high-melting organic product and discharging the remaining high-boiling impurities and such impurities which are not capable of being distilled from the evaporator through a conically tapering sump, while mechanically scraping residue from the sump wall, preferably with the use of a rotating helical screw in the sump; the discharge from the sump being effected into and through an enclosed path at a rate sufficient to prevent liquid accumulating in the sump, while

Abstract: A process for the purification of a mixture of silane and impurities comprising passing the mixture through a succession of zones connected in series, in a closed system, according to the following steps:(a) passing the mixture, in gaseous form, through a zone containing porous, granular charcoal as an adsorbent at a temperature in the range of about minus 40.degree. C to about minus 80.degree. C to provide a mixture of silane and remaining impurities in gaseous form;(b) passing the gaseous mixture from step (a) through a zone containing porous, granular magnesium silicate as a adsorbent at a temperature in the range of about minus 40.degree. C to about minus 80.degree. C to provide a mixture of silane and remaining impurities in gaseous form;(c) passing the gaseous mixture from step (b) into a distillation zone in such a manner that the impurities are removed overhead in gaseous form and at least about 95 per cent by weight of the silane is converted to liquid bottoms; and(d) recovering the bottoms.

Abstract: Process for the separation or purification of heat-sensitive compounds by carrier-vapor distillation, wherein the superheated solvent vapor which is loaded with the compound to be distilled is cooled by treatment with condensed solvent in counter-current and the amount of condensed solvent is measured in such a manner that a saturated solution of the compound which is almost at boiling point is formed from the superheated, loaded vapor. The process being especially apted for separating or purifying 4-hydroxybenzaldehydes optionally substituted by one or more C.sub.1 -C.sub.4 -alkoxy groups.

Abstract: A gas dehydrator system for removing salty water from natural gas, and thereafter subsequently removing the salt and water from the dehydrating agent. The salty water is removed from the gas in a scrubber. The water is then distilled from the dehydrating agent, leaving a salty dehydrating agent from which the salt is crystallized before the agent is recirculated to the scrubber. This expedient prevents undesired crystallization of salt from occurring within the various components of the system.

Abstract: Vinyl halide polymers are removed from the internal surfaces of reaction equipment with a solvent and the solvent recovered by: (1) contacting the polymer-containing solvent with steam forming a slurry; (2) cooling the slurry to form a crumbly precipitate; (3) separating the resulting slurry into an aqueous solvent and a precipitate; (4) adding water to the precipitate to form a second slurry; and (5) separating the second slurry into a second aqueous solvent solution and vinyl halide polymers. The aqueous solvent solutions are dehydrated before being reused in solvent cleaning.

Abstract: Process for the recovery of phthalic anhydride in which gases as obtained in the catalytic atmospheric oxidation of o-xylene or naphthalene are treated with a hydrocarbon containing C.sub.26.sub.- paraffins, cooling, if necessary, the hydrocarbon laden with phthalic anhydride, separating the solid phthalic anhydride followed by melting and distillation thereof.

Abstract: An improved closed-loop process is described for treating waste water resulting from chemical extraction of uranium from ore. The water is evaporated to form a concentrated solution and is then subjected to crystallization of the least soluble salt component thereof via further evaporation, or cooling or simultaneous cooling and a partial vacuum. The crystallized component is then separated from the mother liquor, whereupon the latter is fed back after removal of residual uranium therefrom to the the extraction installation to replace the acids used therein. Additionally, the pure condensate produced during evaporation of the waste waters is employed as a replacement for the fresh water employed in processing of the ore.