Abstract: A dehydration method of a water-containing substance using a liquefied matter, including a step (1) of contacting a liquefied matter of a substance which is in a gas phase under a condition at ambient temperature and atmospheric pressure with the water-containing substance, to dissolve contained water in the water-containing substance into the liquefied matter, for obtaining the liquefied matter containing a large amount of water; and a step (2) of vaporizing the substance out of the liquefied matter containing a large amount of water, to thereby separate the substance as the gas from water.

Abstract: The present invention relates to a process for improving the color stability by postpurifying piperazine, the steps comprising preparing an aqueous piperazine solution by introducing solid or liquid piperazine having a degree of purity of at least 90% by weight in water; removing the water by distillation; isolating the piperazine with a predefined maximum residual content of water. The invention further provides a rapid test of aging for checking the improvement in the color stability.

Abstract: The invention relates to a process for preparing 1-butenic fractions having less than 2000 ppm of isobutene in relation to 1-butene from technical mixtures of C4 hydrocarbons I which contain at least 1-butene and 2000 ppmw to 8% by mass of isobutene based on the 1-butene, with or without n-butane, isobutane and/or 2-butenes.

Abstract: A process for removing trioxane from a use stream I of formaldehyde, trioxane and water, by a) providing a use stream I of formaldehyde as the main component and trioxane and water as the secondary components, b) mixing the use stream I with a recycle stream VII to obtain a feed stream Ia, c) distilling the use stream Ia in a first distillation stage to obtain a stream II of formaldehyde as the main component and water as the secondary component, and a stream III of trioxane as the main component and water and formaldehyde as the secondary components, d) distilling the stream III in a second distillation stage having a pressure higher than in the first distillation stage, to obtain a stream IV of trioxane and a stream V of trioxane as the main component and water and formaldehyde as the secondary components, e) distilling the stream V in a third distillation stage to obtain a stream VI of water and the recycle stream VII of trioxane as the main component and water and formaldehyde as the secondary components

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: Pure halogen salts of alkaline and/or alkaline earth metals or a mixture thereof are prepared by (I) hydrolytically heating a suspension of 1 part by weight of a halogenic, organic waste material in a comminuted state in 1-10 parts by weight of an aqueous medium in the presence of a base to a temperature ranging from 200-300° C. at a pressure sufficient to maintain the water in a liquid state for a period of time sufficient to convert substantially all the organically bound halogen present to inorganic halides, and (II) separating the hydrolysate obtained in step (I) into a solid hydrolysate fraction and a liquid hydrolysate fraction, (III) neutralizing the liquid hydrolysate with hydrohalogenic acid, (IV) adding a flocculent to the neutralized hydrolysate; (V) separating the material from step (IV) into a solid containing fraction and an aqueous solution; and (VI) nanofiltering the aqueous solution to obtain a retentate and a permeate, wherein the permeate is further treated to obtain the pure salts.

Abstract: Systems and methods for recycling waste and reclaiming beneficial and useful compositions such as organic solvents comprises a shredder, operating in an inerted or anaerobic atmosphere, which shreds the waste into smaller pieces that are fed into and indirectly heated in an anaerobic desorption unit so as to vaporize at least one organic compound associated with the waste. A vacuum means is used to transfer the organic compound vapors from the desorption unit to a water quench condensing unit that operates to produce a mixed organic compound liquid stream. The liquid organic compound and water stream is then processed in an oil and water separator. The water is separated and can be reused in the system for quenching gas vapors or inerting the desorption unit. The water-free mixed organic compound liquid stream is then fed into a multi-stage packed distillation column separating organic compound according to boiling points to produce products such as organic solvents.

Abstract: A continuous process is provided for recovering caprolactam from aqueous caprolactam product which includes (i) caprolactam, (ii) impurities, and (iii) water by (a) adding alkali hydroxide to the aqueous caprolactam product, in an amount of not more than 100 mmol alkali hydroxide per kg of caprolactam; (b) reacting at least part of the added alkali hydroxide to form alkali amino caproate, to obtain a caproate-enriched caprolactam product; and (c) distilling the caproate-enriched caprolactam product at reduced pressure.

Abstract: The invention relates to an energy efficient process for the distillative working-up of aqueous amine solutions that occur in the catalytic hydrogenation of nitroaromatic compounds. In this process, the amine is freed from water and also the water is obtained free from amine and low-boiling compounds and the concentrated low-boiling compounds are obtained.

Abstract: A process is described for the recovery of substantially pure ethyl acetate from a feedstock including ethyl acetate, ethanol and water. The process includes supplying the feedstock to a first distillation zone maintained under first distillation conditions effective for distilling from the feedstock a first distillate including ethyl acetate, ethanol, and less than about 10 mol % water. The first distillate is recovered from the first distillation zone and is supplied to a second distillation zone maintained under second distillation conditions, which include use of a higher pressure than that of the first distillation zone. The second distillation conditions are effective for distilling from the first distillate a second distillate including ethanol, water, and a minor proportion of ethyl acetate and yielding a substantially pure ethyl acetate bottom product, which is recovered. The second distillate is returned to the first distillation zone.

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.

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: The invention relates to a process for separating close-boiling, homo- and heteroazeotropic mixtures by using ionic liquids. Due to the selectivity and unusual combination of properties of the ionic liquids the process is superior to conventional extractive rectification from the point of view of costs and energy.

Abstract: An improved distillation of water. involves distilling significant quantities of water at temperatures well below the boiling point. During distillation, a compound is taken from a liquid-phase to a gas-phase and then condensed to the liquid-phase again to get a pure liquid. The present invention uses water sprayed (105) and absorbed onto a solid surface such as micro-powder (104) made from wood as a starting material. Absorbing water onto such a surface results in rapid evaporation with a relatively low temperature gradient when the water and particles are agitated. The present invention could be characterized as solid-phase distillation.

Abstract: The present invention provides a method and a system for stripping volatile compounds such as ammonia from liquids. Part of the ammonia is stripped from the liquid in a system having a shunt through which liquid such as e.g. fermented biomass can be diverted in the form of a side stream in liquid contact with a main fermentor(s). The stripper system is connected to an evaporator. In the evaporator aqueous liquid is heated at a pressure below atmospheric pressure whereby vapor is developed at a temperature below 100° C. The vapor from the evaporator is directed to the liquid medium containing ammonia and this results in ammonia being stripped from the liquid and transferred to the vapor phase. The vapor phase is condensed in a first condenser at a low pressure, and the liquid thus obtained is further treated in a stripper unit at a higher pressure.

Abstract: The invention relates to a method and a device for the purification of an aqueous solution of an organic acid having a boiling point at atmospheric pressure of less than 450° C., which further has approximately 275 g carboxylate ions/1 or less, preferably 250 g carboxylate ions/1 or less, and preferably less than 1% by weight ionic impurities, calculated on the basis of the total solution. In particular, the invention relates to a method and a device for the continuous purification and concentration, on an industrial scale, of an aqueous solution of an organic acid having a boiling point at atmospheric pressure of less than 450° C. According to the method, this solution is subjected to two or more distillation steps, the first distillation step being carried out at a temperature of from 80° to 150° C. and a pressure of from 50 to 250 mbar, and the second distillation step being carried out at a temperature of from 80° to 200° C. and a pressure of from 0.01 to 50 mbar.

Abstract: Aromatic amines are produced by catalytic hydrogenation of aromatic nitro compounds. The reaction mixture generated by this hydrogenation is then worked up by distillation in a manner which makes it possible to substantially free the amine of water with increased energy efficiency. Water free of amine and low boilers and the low boiling materials are also obtained.

Abstract: A method for the preparation of pulp by means of alkaline cooking, in which method spent liquor is transferred to pressurized tanks, and at least one liquor is expanded corresponding to a temperature difference of 1 to 5° C. The generated steam is led to turpentine recovery. Thus, the removal of turpentine and gases dissolved in said liquor is effective, the amount of recovered turpentine increases, and pulp of better washability and higher quality is obtained.

Abstract: A method and a plant are disclosed for purifying lactams, particularly lactams obtained by cyclizing hydrolysis of aminonitrile. The purification of ?-caprolactam obtained by cyclizing hydrolysis of aminocapronitrile is described which includes eliminating the ammonia from the reaction medium of the hydrolysis, then recovering the lactam from said medium in purified form. The recovery is carried out by performing at least a distillation of the lactam in the presence of a base producing optionally a fronts fraction comprising compounds more volatile than the lactam, a fraction comprising the lactam to be recovered to the degree of desired purity and a distillation tails comprising the lactam and compounds less volatile than the lactam. The distillation tails are treated by various processes such as evaporation in thin layers to recover the major part of the caprolactam and recycling the latter in the purification process.

Abstract: Provided are liquid perfluoro-n-alkanes that are highly transparent to UV wavelengths ranging from about 150 nm to 165 nm, and to the method by which high transparency may be obtained. The liquid, perfluoro-n-alkanes are useful in optical couplants, optical cements, optical elements, optical inspection media for semiconductor wafers and devices, and immersion photolithography at 157 nm exposure wavelength.

Abstract: Crude water-containing tetrahydrofuran is purified by passing the crude tetrahydrofuran through three distillation columns, withdrawing water from the bottom of the first column, recycling water-containing tetrahydrofuran from the top of the second column into the first column, passing a sidestream of the first column into the second column, recycling the bottom product of the third column into the first column, and withdrawing a distillate at the top of the first column. Additionally, a sidestream of the second column is passed into the third column and the purified tetrahydrofuran is recovered as the top product of the third column.

Abstract: A method for dehydrating an aqueous composition comprising lithium bis(pentafluoroethanesulfonyl)imide and at least one organic solvent, wherein a part of solvent is distilled off by distillation.

Abstract: A compact, energy efficient, continuous-flow point of use distillation system utilizes stacked, vertically-arranged components to provide a compact and energy efficient distillation process and a device which is quick and easy to service and maintain. A housing contains a double-walled boiler vessel to which water is supplied from an external source through suitable filters. A heating source is provided to boil water in the vessel, producing steam which is supplied through a condenser to a storage container located below the boiler. A noninvasive liquid level sensor maintains the water level in the boiler and the controller is provided to activate the boiler when water is required for the storage reservoir.

Abstract: This invention provides azeotrope-like compositions of 1,1,1,3,3-pentafluoropropane and water that are environmentally desirable for use as refrigerants, aerosol propellants, metered dose inhalers, blowing agents for polymer foam, heat transfer media, and gaseous dielectrics.

Abstract: A system for recovering methylene chloride from an aqueous waste stream is disclosed. The system includes a distillation unit, at least one heat transfer unit, receptacles for methylene chloride and waste product, a temperature probe and a controller configured to selectively divert product flow from the distillation unit to either of the receptacles or to a recycle line back to the distillation unit depending upon the temperature measured by the probe. Also disclosed is a related process of recovering methylene chloride with such a system.

Abstract: A process for reducing the level(s) of water and/or other impurities from cyclosiloxanes by either azeotropic distillation, or by contacting the cyclosiloxane compositions with an adsorbent bed material. The purified cyclosiloxane material is useful for forming low-dielectric constant thin films having dielectric constants of less than 3.0, more preferably 2.8 to 2.0.

Abstract: A process for preparing a salt-free aqueous hydroxylamine solution by reacting an aqueous solution of a hydroxylammonium salt with a base to give a mixture and separating from said mixture by distillation a salt-free aqueous hydroxylamine solution, involving using as a base an aqueous solution of a mixture of NaOH and KOH in a molar ratio Na+:K+ in the range from 70:30 to 95:5 and with a total concentration of Na+ and K+ in the range from 0.1 to 10 m/m % based on the total amount of the mixture.

Abstract: Disclosed is a process for removing DME from a stream containing C4 olefins. The process includes providing a first stream comprising C4 olefins, C5+ hydrocarbons, DME, and methanol. The first stream is separated into a second stream comprising the C4 olefins and the DME and a third stream comprising the C5+ hydrocarbons and the methanol. The second stream is directed to a DME absorption unit, wherein the second stream contacts water under conditions effective to separate the C4 olefins from the DME. Also disclosed is a process including contacting the first stream with water in a methanol removal unit under conditions effective to separate remove the methanol therefrom; distilling the methanol-depleted stream to remove C5+ hydrocarbon components, and contacting the stream with water in a DME removal unit under conditions effective to form an overhead stream comprising the C4 olefins and a bottoms stream comprising the DME.

Abstract: An amine-containing mixture containing one or more amines, water, low-boilers and optionally high-boilers is fractionated by a process having the steps (iii) and (iv) and optionally the steps (i), (ii) and (v): (i) a (first) low-boiler fraction is separated off from the amine-containing mixture by distillation, (ii) a (first) high-boiler fraction is separated off from the amine-containing mixture by distillation, (iii) the amine-containing mixture is extracted with sodium hydroxide solution, producing an aqueous, sodium-hydroxide-containing first phase and an aqueous-organic, amine-, (further) low-boiler- and possibly (further) high-boiler-containing second phase, (iv) the aqueous-organic second phase, is distilled, producing essentially anhydrous amine as bottom-phase take off or sidestream takeoff in the stripping part of the distillation column, an amine/water azeotrop as sidestream takeoff in the enrichment part of the column and a (further) low-boiler fraction as overhead takeoff, and recycling the amin

Abstract: Cyclic esters of hydroxy organic acids can be produced and recovered via azeotropic distillation. In certain embodiments cyclic esters, such as glycolide and lactide, can be produced from a fermentation broth or other feed stream that contains a hydroxy organic acid, an ammonium salt of a hydroxy organic acid, an amide of a hydroxy organic acid, or an ester of a hydroxy organic acid using azeotropic distillation. The hydroxy organic acid of the feed stream or the hydroxy organic acid derived from the feed stream by decomposition is reacted to produce the cyclic ester. In other embodiments a crude composition of a cyclic ester of an organic ester can be purified using azeotropic distillation.

Abstract: The subject invention provides polyurethane foam and a method of purifying polyether polyols of non-volatile impurities for use in forming the polyurethane foam. The method includes the step of providing a crude polyether polyol having a non-volatile impurity present therein. The crude polyether polyol is contacted with an adsorbent selected from at least one of activated carbon, diatomaceous earth, charcoal, attapulgite, and clay to remove the impurity and filtered to form a purified polyether polyol. The filtering of the crude polyether polyol is carried out through a filter media that is used both in a pre-filtering step prior to adding the adsorbent and the filtering step to remove the adsorbent to reduce losses of the purified polyether polyol because of its high viscosity. The purified polyether polyol is then used to form a polyurethane foam having improved stability.

Abstract: A process for preparing a salt-free aqueous hydroxylamine solution by distilling an aqueous solution of a hydroxylammonium salt and a base in a tray column having at least two mechanical trays, wherein random or structured packings are located above at least one tray of the tray column over the cross section of the column.

Abstract: A mixture containing one or more amines, water, low-boilers and high-boilers, is fractioned in a process wherein (i) low-boilers are separated from the mixture by distillation, (ii) high-boilers are separated from the mixture by distillation, (iii) the mixture is extracted with a sodium hydroxide solution to form an aqueous, sodium-hydroxide-containing first phase and an aqueous-organic, amine-containing second phase, and (iv) the aqueous-organic second phase is distilled to form an amine/water azeotrop and an essentially anhydrous amine, and the amine/water azeotrop is recycled to the extraction step (iii).

Abstract: A process is described for the recovery of acrylonitrile from an ammoxidation reactor effluent stream containing acrylonitrile, water, and organic impurities. The process includes the steps of (a) quenching an ammoxidation reactor effluent stream that includes acrylonitrile, water, and organic impurities with an aqueous quench stream, thereby producing a cooled reactor effluent stream; (b) passing the cooled reactor effluent stream through an absorption column, thereby generating an absorber bottoms stream that includes water, acrylonitrile, and organic impurities; and (c) passing the absorber bottoms stream through a single recovery/stripper column, generating an acrylonitrile-rich overhead stream, a lean water side stream, and a recovery/stripper bottoms stream that includes organic impurities. The acrylonitrile-rich overhead stream can be passed through a decanter to separate water from acrylonitrile. The lean water side stream can be recycled for use in the absorption column.

Abstract: A process for the preparation of propylene oxide in the presence of methanol, in which propylene oxide is separated from a mixture propylene oxide and methanol, and the resultant methanol containing mixture is worked up, including seperating methanol from a mixture comprising methanol and methyl formate during the work-up.

Abstract: The present invention relates to a process for preparing anhydrous hydrazine. The process can include distilling an unconcentrated aqueous hydrazine solution into a starting binary solution, distilling the starting binary solution at a pressure where a concentration of hydrazine in the binary solution is greater than a concentration of an azeotrope at the distillation pressure, and recovering the anhydrous hydrazine.

Abstract: A water-soluble organic material condensation apparatus equipped with a distillation column for distilling an aqueous solution of a water-soluble organic material, wherein a vapor generated at the top of the distillation column or a condensed liquid from the vapor is introduced to a device other than the distillation column which has the function to separate water from the water-soluble organic material to thereby condense the water-soluble organic material through separating water and then the condensed water-soluble organic material is recycled to the distillation column. The device other than the distillation column is desirably a separative film such as a zeolite film. The apparatus is improved in the operation of the upper portion of the condensation section of the distillation column and allows energy savings during distillation.

Abstract: In a process for purification of ethylene oxide by distillation an aqueous mixture comprising ethylene oxide, formaldehyde and at least 5% by weight of water is introduced via a feed into a distillation apparatus comprising at least one distillation column, the mixture being introduced at a height above the bottom of at least 8 theoretical stages, the ethylene oxide is taken off at the top and in the bottom phase a mixture is obtained which contains less than 5% by weight of ethylene oxide.

Abstract: A method and apparatus for cleaning condensate, produced during the production of cellulose pulp, including evaporation of spent liquor, utilizing a cleaning plant having several condensers, coupled in series. Process steam from the last evaporation stage and unclean condensate are introduced into a combined stripper/condenser, the process steam and the condensate being brought to flow in opposite directions so that direct heat exchange occurs, resulting in volatile compounds of the condensate being separated and taken up by the steam with simultaneous indirect cooling, resulting in condensation of the main part of the process steam, and the remaining process steam gradually flowing further on, the process steam being successively cooled first resulting in water and turpentine being condensed and collected and subsequently methanol being condensed.

Abstract: A mixture containing mixture one or more amines, water, low-boilers and high-boilers, is fractioned in a process wherein (i) low-boilers are separated from the mixture by distillation, (ii) high-boilers are separated from the mixture by distillation, (iii) the mixture is extracted with a sodium hydroxide solution to form an aqueous, sodium-hydroxide-containing first phase and an aqueous-organic, amine-containing second phase, and (iv) the aqueous-organic second phase is distilled to form an amine/water azeotrope and an essentially anhydrous amine, and the amine/water azeotrope is recycled to the extraction step (iii).

Abstract: This invention relates to a process for the purification of phenols in a feedstock containing phenols and neutral oils and/or tar bases. The process includes liquid-liquid extraction of feedstock using a solvent and a counter-solvent, and separating the resulting solvent and counter-solvent layers. Phenols are then recovered from the separated solvent layer, and counter-solvent is recovered form the counter-solvent layer. The process also includes at least one of the following additions steps i) subjecting the separated solvent layer to distillation at atmospheric pressure; ii) subjecting the separated solvent layer to distillation, recovering an organic phase from the overheads product of the distillation step and recycling it to the liquid-liquid extraction step; and iii) recovering solvent from the counter-solvent layer.

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 process for preparing a salt-free aqueous hydroxylamine solution by reacting an aqueous solution of a hydroxylammonium salt with a base to give a mixture and separating from said mixture by distillation a salt-free aqueous hydroxylamine solution, comprises using as a base an aqueous solution of a mixture of NaOH and KOH in a molar ratio Na+:K+ in the range from 70:30 to 95:5 and with a total concentration of Na+ and K+ in the range from 0.1 to 10 m/m % based on the total amount of the mixture.

Abstract: A process for producing high purity isopropyl alcohol. In one embodiment, the process includes the steps of: (a) feeding a feed stream comprising at least about 99.9 wt. % isopropyl alcohol into a separation column; (b) separating the isopropyl alcohol into an overhead stream taken overhead from the separation column and a bottoms stream taken as bottoms from the separation column; and (c) removing the high purity isopropyl alcohol at a point: (i) below where the feed stream enters the separation column but above the bottoms stream, or (ii) above where the feed stream enters the separation column but below the overhead stream. The high purity isopropyl alcohol has a metals content of less than about 1 ppb and a water content of less than about 100 ppm.

Abstract: A process is disclosed for the purification, by distillation, of trimethylolpropane originating from the hydrogenation of 2,2-dimethylolbutanal, said process including the following steps: (a) reaction of n-butyraldehyde with formaldehyde in the presence of catalytic amounts of a tertiary amine, and hydrogenation of the resulting mixture to give a mixture containing trimethylolpropane; (b) separation of water, methanol, trialkylamine and/or trialkylammonium formate by distillation; (c) heating of the residue obtained in (b) under reduced pressure to a temperature at which TMP is volatile and compounds boiling above TMP are cleaved, in order to separate off, by distillation, TMP and compounds more volatile than TMP; (d) distillation of the distillate obtained in (c) in order to separate off the more volatile compounds and recover pure TMP; and (e) optional distillation of the TMP obtained in (d) in order to recover TMP with a low APHA color index.

Abstract: A method and an apparatus for reclaiming deicer from produced water of an oil or gas well includes a fractionation tower having a top condenser section, a bottom heat exchanger section and an intermediate packing section. A deicer outlet is positioned in the condenser section, for removal of condensed deicer. An inlet is provided to receive produced water contaminated by deicer. The inlet is coupled to the condenser section such that produced water must pass through the condenser to enter the inlet. A water outlet is provided in the heat exchanger section. Operation of the water outlet is controlled to maintain a predetermined level of accumulated water in the heat exchanger section. The heat exchanger is adapted to be coupled with a source of hot fluids produced by an external heat source. The circulation of hot fluids through the heat exchanger heats accumulated water in the heat exchanger section.

Abstract: The present invention relates to a process for separating the water from an aqueous lactam solution. It applies more particularly to a mixture resulting from the reaction between an aminonitrile and water (this reaction also being called cyclizing hydrolysis). The subject of the invention is a process for separating the water from an aqueous lactam solution, which process is economical both from the standpoint of the investment necessary for its implementation and from the standpoint of the operating cost.

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: A process for the preparation of propylene oxide in the presence of methanol, in which propylene oxide is separated from a mixture comprising propylene oxide and methanol, and the resultant mixture comprising methanol is worked up, which comprises separating methanol from a mixture comprising methanol and methyl formate during the work-up.

Abstract: This invention relates to a process for the purification of phenols in a feedstock containing phenols and neutral oils and/or tar bases. The process includes liquid-liquid extraction of feedstock using a solvent and a counter-solvent, and separating the resulting solvent and counter-solvent layers. Phenols are then recovered from the separated solvent layer, and counter-solvent is recovered form the counter-solvent layer. The process also includes at least one of the following additions steps i) subjecting the separated solvent layer to distillation at atmospheric pressure; ii) subjecting the separated solvent layer to distillation, recovering an organic phase from the overheads product of the distillation step and recycling it to the liquid-liquid extraction step; and iii) recovering solvent from the counter-solvent layer.