Abstract: In an embodiment a method of purifying acetone, comprises directing a feed stream comprising greater than or equal to 97 wt % of acetone and 100 to 1,000 ppm of methanol to a separation column, both based on a total weight of the feed stream; separating the feed stream in the separation column that is operating at a pressure greater than or equal to 1 bar into an overhead stream and a purified acetone stream comprising less than or equal to 50 ppm of methanol based on a total weight of the purified acetone stream; and directing at least 80 wt % of the overhead stream into the separation column as a reconstituted stream and purging 1 to 20 wt % of the overhead stream as a purge stream.

Abstract: Provided are a method and an apparatus for recovering (meth)acrylic acid. The recovering method is used to save the energy required for a process of recovering (meth)acrylic acid because a process of separating high-boiling point by-products can be omitted, and to minimize a possibility of (meth)acrylic acid polymerization during the process of recovering (meth)acrylic acid. Therefore, the recovering method is used to obtain (meth)acrylic acid with less energy in a high yield.

Abstract: The disclosure relates to a process for separating propylene oxide for a crude propylene oxide stream, for example an intermediate stream from a PO/TBA process. The crude propylene oxide stream can be passed through an extractive distillation column. The distillation column is operated at a pressure in a range of greater than 25 up to 50 psig, and/or at a temperature in a range of from 70 to 150 degrees Celsius using C8-C20 paraffin as extractive solvent with an overhead distillate water wash drum. The crude propylene oxide stream include from 0.001 to 0.1 wt % methanol, based on the total composition of the crude propylene oxide stream. The systems, methods, and apparatuses can produce a propylene oxide stream having less formaldehyde and acetaldehyde than the prior art.

Abstract: Solvent regeneration to recover a polar hydrocarbon (HC) selective solvent substantially free of hydrocarbons (HCs) and other impurities from a solvent-rich stream containing selective solvent, heavy HCs, and polymeric materials (PMs) generated from reactions among thermally decomposed or oxidized solvent, heavy HCs, and additives is provided. A combination of displacement agent and associated co-displacement agent squeezes out the heavy HCs and PMs from the extractive solvent within a solvent clean-up zone. Simultaneously, a filter equipped with a magnetic field is positioned in a lean solvent circulation line to remove paramagnetic contaminants. The presence of the co-displacement agent significantly enhances the capability of the displacement agent in removing the heavy HCs and PMs from the extractive solvent.

Abstract: Process for obtaining formic acid by thermal separation of a stream comprising formic acid and a tertiary amine (I), in which a liquid stream comprising formic acid, tertiary amine (I) and water is produced by combining tertiary amine (I) and a formic acid source in the presence of water, water and organic decomposition products of the tertiary amine (I) are removed and formic acid is removed by distillation from the resulting liquid stream in a distillation apparatus, wherein the stream comprising water and organic decomposition products of the tertiary amine (I) which have been separated off is separated into two liquid phases, the upper liquid phase is removed and the lower, water-comprising liquid phase is recirculated to the formic acid source.

Abstract: The present process separates acrylic acid from a composition containing acrylic acid and at least one accompanying product. The process first involves contacting the composition with an aqueous liquid stream to give a liquid solution of acrylic acid, accompanying product, and water. The water then forms an azeotrope with an entrainer, which is added to the solution. Distillation then separates the solution into an overhead product containing the azeotrope and a bottom product containing acrylic acid and accompanying product. The overhead product is separated into water and entrainer and the bottom product is separated in a distillation column into acrylic acid and accompanying product. The process provides a way to remove high- and low-boiling products with a small number of distillation columns.

Abstract: High purity 1,3 butadiene is recovered from a C4 fraction containing butadienes, butenes, butanes, and acetylenes that is generated from a steam cracker by extractive distillation operating with no reflux or greatly reduced reflux conditions. This no reflux (or minimum reflux) technique is generally applicable to any butadiene recovery process in which at least one extractive distillation column (EDC) is used to separate 1,3 butadiene from other C4 components in the mixture. For an ED process with two EDCs, significant reductions in total energy requirements in the both EDCs can be achieved by appropriate reductions in the reflux in each column. The performances of both EDCs are unaffected even when operating at no reflux.

Abstract: Methods for removing methanol from acetone recycle streams during bisphenol-A production, thereby avoiding the deactivation of catalyst, by distilling an acetone-methanol-water comprising mixture such that acetone is taken overhead in form of a relatively pure distillate, and substantial portions of the methanol and the water are leaving with the bottom product.

Abstract: A method for purifying water and generating ammonia liquor is disclosed. Hydrogen, oxygen, organic matter contaminated water vapor, and ambient air, containing nitrogen, are provided to a combustion chamber. The hydrogen is combusted in the oxygen in the combustion chamber with the contaminated water vapor and nitrogen. The nitrogen is fixated. Water vapor is produced. The contaminated water vapor is heated to decontaminate the contaminated water vapor. The produced water vapor, fixated nitrogen, and organic matter decontaminated water vapor are exhausted from the combustion chamber. The generated water vapor, fixated nitrogen, and decontaminated water vapor are condensed to obtain ammonia liquor. Water is evaporated from the ammonia liquor to form purified water vapor and concentrate the ammonia liquor.

Abstract: Product propylene oxide in a reaction mixture resulting from the reaction of propylene, oxygen and hydrogen or from the reaction of propylene and hydrogen peroxide is separated from propylene and/or propane by extractive distillation using methanol and/or water extractive distillation solvent.

Abstract: In the water purification process, apparatus, and method, contaminated water vapor is exposed to liquid solvent, which causes a transfer of contaminants from the contaminated water vapor to the liquid solvent. In an advantageous embodiment, this latter step is followed by a second purification step where the decontaminated water in liquid phase is exposed to water vapor which causes a transfer of solvent remaining in the decontaminated water to the water vapor. The energy freed during the condensation of the vapor can advantageously be used for evaporation of the liquids, optionally by compressing the vapors prior to condensation thereof within heat exchangers.

Abstract: A novel method for connecting multiple existing columns which are retrofitted into vapor-liquid contacting devices with trays or packings suitable for the operation of a three-phase (vapor-liquid-liquid) extractive distillation column for aromatics recovery. The retrofitted columns are connected by a vapor transfer line to transfer the vapor phase from the top of the lower column to the bottom of the upper column, and by a liquid transfer line to transfer the liquid phase from the bottom of the upper column to the top of the lower column of the three-phase extractive distillation column.

Abstract: The present invention relates to methods and systems for processing an exhaust stream containing a recyclable component mixed with other components and impurities to produce a high purity product that contains all of the recyclable component. One or more waste streams containing none of the recyclable component are also produced. The present invention particularly relates to the recovery of valuable recyclable components used in the manufacture of semiconductor devices.

Abstract: A method of separating propylene oxide from a mixture (M) comprising 5 to 50 percent by weight propylene oxide and 50 to 85 percent by weight methanol, said method comprising (i) introducing said mixture (M) into an extractive distillation column; (ii) additionally introducing a polar solvent into said extractive distillation column; (iii) distilling propylene oxide overhead from said extractive distillation column at a bottoms temperature of from 40 to 70° C. and at a pressure of from 300 to 750 mbar.

Abstract: This invention provides azeotrope-like compositions of 1,1,1,2-tetrafluoroethane, 1,1,1,3,3-pentafluoropropane-245fa 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 process for the removal of sulfur compounds from a hydrocarbon stream is disclosed. In a preferred embodiment, the process includes extractive distillation of a gasoline stream from a fluid catalytic cracker to reject olefins to a raffinate stream and simultaneously extract sulfur compounds to an extract stream.

Abstract: A process for working up crude, liquid vinyl acetate feed containing acetic acid, water and ethyl acetate and optionally smaller amounts of other impurities by distillation, wherein there is introduced into the distillation column, above the feed point of the crude, liquid vinyl acetate, 0.1 to 5% by weight of water, based on the crude, liquid vinyl acetate feed, and 0.1 to 60% by weight of acetic acid, based on the crude, liquid vinyl acetate feed.

Abstract: An extractive distillation process for separating at least one substituted unsaturated aromatic from a pyrolysis gasoline mixture, containing said aromatic and at least one close-boiling aromatic or non-aromatic hydrocarbon, employing a two part extractive solvent, the first part selected from propylene carbonate, sulfolane (tetramethylene sulfone), methyl carbitol, 1-methyl-2-pyrrolidinone, 2-pyrrolidinone and mixtures thereof, and the second portion consisting of water.

Abstract: Benzene and other aromatics are separated from a stream of mixed hydrocarbons containing both aromatics and non-aromatics by extractive distillation with a solvent system containing dimethyl sulfoxide and optionally a co-solvent, preferably water, followed by distillation stripping of the aromatics from the enriched solvent system, and recycle of the lean solvent system to the extractive distillation step.

Abstract: A process for removing acetone from an acetone/methyl acetate/methyl iodide mixture utilizing extractive distillation with water being introduced to the distillation zone above the point of introduction of the mixture and acetic acid being introduced at or above the point of introduction of the mixture. In a preferred embodiment the mixture is subjected to an initial extraction with an aqueous extractant to remove most of the methyl iodide.The process is particularly applicable to removing acetone by-product in carbonylation processes for the production of acetic anhydride.

Abstract: An extractive distillation process for separating at least one C.sub.2 -C.sub.4 alkene (preferably propylene) from at least one close-boiling alkane (preferably propane) employs propylene carbonate as solvent, optionally in admixture with a minor amount of water.

Abstract: Provided by this invention is a process for producing a purified hydrazine hydrate having a low total organic carbon concentration and which involves:a first step which includes distilling an aqueous solution of hydrazine hydrate in the presence of at least one salt selected from the group consisting of chloride, sulfate, phosphate and carbonate of (a) the metals of Group Ia and IIa of the Periodic Table of the Elements, (b) ammonium or (c) hydrazinium to concentrate the aqueous solution of hydrazine hydrate by distilling water and the majority of the total organic carbon constituents off and separating the resultant concentrate as a bottom product, anda second step which includes distilling the resultant concentrate to recover a purified aqueous solution of hydrazine hydrate as a top product and separating an aqueous solution of the above salt as a bottom product.

Abstract: A method of distillation employing a heat pump (which may be driven by a compressor) using a vapor stream from within the distillation system as a heat source and a liquid stream from within the distillation system as a heat sink. The selection of heat-source vapors and heat-sink liquid is such that at least one is withdrawn from the phase-contacting region of the distillation system. The return of streams withdrawn from the phase-contacting region of the distillation system to the distillation system is such that at least one of the streams is returned at a temperature different from that of the point from which it was withdrawn, and all withdrawn streams are returned in manner such that a stream removed as vapor is returned at a point with a temperature at most that at the point it was withdrawn, and a stream removed as liquid is returned at a point with a temperature at least that at which it was withdrawn.

Abstract: An extractive distillation process for separating at least one cycloalkane or aromatic hydrocarbon from at least one close-boiling alkane employs as solvent at least one N-mercaptoalkyl-2-pyrrolidone, preferably N-(.beta.-mercaptoethyl)-2-pyrrolidone, either alone or in admixture with about 0.1-10 weight-% water.A liquid-liquid extraction process for separating at least one cycloalkane or aromatic hydrocarbon from at least one alkane employs as solvent at least one N-mercaptoalkyl-2-pyrrolidone, preferably N-(.beta.-mercaptoethyl)-2-pyrrolidone, either alone or in admixture with about 0.1-10 weight-% water.

Abstract: A mixture of (a) at least one N-alkyl-2-pyrrolidone (preferably N-methyl-2-pyrrolidone) and (b) at least one sulfolane (preferably unsubstituted sulfolane) is used as solvent in the extractive distillation of feed mixture of cycloalkane(s) (in particular cyclohexane) and close-boiling alkane(s).

Abstract: A process for purifying diethoxymethane from a mixture containing ethanol and, optionally, water. The process involves the addition of an amount of water, DEM, or an appropriate mixture of any two or three of water, DEM and ethanol that is effective in moving the mixture into the two liquid phase region on an equilibrium tie-line which crosses the critical distillation boundary without the need for additional azeotrope-forming agents such as cyclohexane.

Abstract: The separation of homozeotropic mixtures of a paraffin or paraffins of 6-14 carbon atoms and an alcohol or alcohols of 4-8 carbon atoms is conducted in two rectification steps. In a first step, rectification is carried out in the presence of water as the azeotropic agent, and the resultant distillate, after condensation, is separated into two liquid phases. The thus-obtained organic phase is rectified in a further step without the addition of water, and the head product consisting of an alcohol/paraffin mixture is recycled into the first step. The paraffin or paraffins and the alcohol or alcohols are obtained in the lower section of the individual rectifying step or steps. The water which may be present in the starting mixture is removed from the cycle. Low-boiling paraffins and/or low-boiling alcohols are suitable as additional azeotropic agents.

Abstract: Phenol containing MBF impurity is distilled in the presence of water and an extraction solvent for MBF (preferably AMS and/or cumene) to recover a phenol bottoms having reduced impurities. The use of solvent permits a reduction in the amount of water used, which reduces the amount of phenol in the overhead, thereby lowering costs.

Abstract: A process for preparing esters which comprises reacting a polycarboxylic acid with an excess of alcohol and in the presence of an organotitanate catalyst, treating the crude mixture with a suitable chelate compound, removing the unreacted alcohol and hydrolyzing the treated titanium catalyst residues with steam, and recovering the purified ester by filtration.

Abstract: In a process for producing butadiene or isoprene having a high purity comprising a step of treating a C.sub.4 or C.sub.

Abstract: A vapor-liquid extractive distillation process utilizing a dialkyl sulfone containing 4 to 8 carbon atoms per molecule and at least one percent water as the solvent. The process according to this invention is of particular applicability in separating aromatics from nonaromatics in a BTX stream. The solvent system operates particularly well with relatively large amounts of water.

Abstract: The present invention relates to a continuous process for producing substantially anhydrous alcohols from aqueous solutions thereof by distilling a mixture of aqueous alcohol and an entrainer to a drying column withdrawing an azeotrope as a distillate and continuously recovering anhydrous alcohol with less than 0.1% by weight of water from the base of the drying column. The improvement resides in feeding the distillate to a condenser and introducing (a) the condensate therefrom in a substantially non-turbulent state into a decanter at a point close to the interface between the aqueous and organic phases present therein and (b) a specified amount of water, which is less than 0.25 volumes per volume of the anhydrous alcohol recovered, into the drying column at a point adjacent to that at which the organic hydrocarbon phase is returned as reflux.

Abstract: A process for isolating a conjugated diolefin from a C.sub.4 - or C.sub.5 -hydrocarbon mixture containing the diolefin, by single-stage or multi-stage extractive distillation using a selective solvent, wherein the selective solvent is a solvent mixture which comprises(a) from 50 to 99 percent by weight of a selective solvent boiling at from 140.degree. C. to 260.degree. C. and(b) from 1 to 50 percent by weight of an organic solvent boiling at from 45.degree. C. to 125.degree. C.

Abstract: A process for the purification of olefine oxides by subjecting a mixture containing the olefine oxides to distillation in a distillation column in the presence of a small amount of water in order to obtain olefine oxide as the distillate. A fraction of the down-flow liquid is withdrawn from the column and the withdrawn fraction is subjected to decantation, so as to separate off an aqueous phase which is discarded, and an organic phase. The organic phase is returned to the column at a point located below the withdrawal point.

Abstract: Disclosed is an improved method of forming polyol (allyl carbonate) monomers. In the disclosed method, the organic by-products as diallyl carbonate and unreacted reagents as allyl alcohol are separated from the brine and wash water derived aqueous phase and returned to the allyl carbonate synthesis reaction. The aqueous phase is further separated to recover allyl alcohol therefrom, which is returned to the allyl carbonate synthesis reactor as an azeotrope.

Abstract: A process for isolating a conjugated diolefin from a C.sub.4 - or C.sub.5 -hydrocarbon mixture containing the diolefin, by single-stage or multi-stage extractive distillation using a selective solvent, wherein the selective solvent is a solvent mixture which comprises(a) from 1 to 99 percent by weight of an N-alkyl-substituted lower aliphatic acid amide or of an N-alkyl-substituted alicyclic acid amide having 5 ring members and(b) from 1 to 99 percent by weight of an aliphatic or alicyclic ether boiling at from 30.degree. C. to 200.degree. C.

Abstract: A process for isolating a conjugated diolefin from a C.sub.4 - or C.sub.5 -hydrocarbon mixture containing the diolefin, by single-stage or multi-stage extractive distillation using a selective solvent, wherein the selective solvent is a solvent mixture which comprises(a) from 1 to 99 percent by weight of an N-alkyl-substituted lower aliphatic acid amide or of an N-alkyl-substituted alicyclic acid amide having 5 ring members and(b) from 1 to 99 percent by weight of an lower aliphatic carboxylic acid ester or carbonic acid ester boiling at from 30.degree. C. to 200.degree. C.

Abstract: The separation of butadiene-1,3 from other C-4 hydrocarbons of lesser degree of unsaturation by extractive distillation with alkoxynitrile or aqueous alkoxynitrile as selective solvent is carried out with improved selectivity, without appreciable formation of butadiene-1,3 polymer and with consequent savings in energy by adding to the alkoxynitrile or aqueous alkoxynitrile an organic cosolvent which is dimethyl sulfoxide, sulfolane, butyrolactone, N-methyl pyrrolidone, morpholine, or trimethyl phosphate and/or an inhibitor which is 2,4-dinitrophenol or 2,4-dinitro-ortho-cresol. The organic cosolvent is present in the selective solvent composition in an amount of 5 to 30 percent by weight and the inhibitor in an amount of 0.05 to 0.6 percent by weight.

Abstract: Formation of butadiene-1,3 polymer during the extractive distillation of a C-4 hydrocarbon mixture to separate and purify butadiene-1,3 using a solvent composition in which an alkoxynitrile is present in a proportion of 50-99 percent by weight, is decreased through inclusion in the solvent of a synergistic combination of 2,4-dinitrophenol and phosphoric acid, each in a proportion of 0.05 to 0.5 percent by weight.

Abstract: Process for separating benzene and/or toluene from mixtures thereof with saturated hydrocarbons, by extractive distillation using an aliphatic N-alkylamide as extraction solvent, comprising introducing in the distillation column, above the level of introduction of the extraction solvent, liquid water in an amount and under such conditions that said water is completely vaporized without substantially diluting the solvent, condensing the vapors discharged from the top of the column and dividing the resulting condensate into a phase of liquid saturated hydrocarbons, and a phase of water.

Abstract: Acetylenic hydrocarbons are removed from a C.sub.4 - or C.sub.5 - hydrocarbon mixture containing a C.sub.4 - or C.sub.5 - diolefin respectively. The feedstock (e.g. a C.sub.4 - or C.sub.5 - cut from an ethylene plant) is extractively distilled to remove paraffins and mono-olefins in the raffinate, using acetonitrile (ACN), dimethyl formamide (DMF), furfural, acetone, dimethylacetamide or N-methyl-2-pyrrolidone mixed with 0-12 weight percent water as the extraction solvent. The bottoms from this first extractive distillation is subjected to a second extractive distillation in which virtually acetylenes-free solvent is used. Isoprene is withdrawn as the distillate with substantially reduced acetylenes content. The bottoms of the second extractive distillation is split three ways. Two streams are handled conventionally (recycle and heavies removal). The third is stripped free of acetylenes so that it may be used as solvent in the second extractive distillation.

Abstract: Butadiene is recovered from a hydrocarbon fraction containing it together with butenes and acetylene hydrocarbons by introducing said fraction into a first extractive distillation column, feeding aqueous acetonitrile into said column above the introduction point of said fraction and extracting a vapor stream containing butadiene below said introduction point; feeding said vapor stream into a second extractive distillation column, feeding aqueous acetonitrile above the introduction point of said vapor stream and recovering a vapor stream consisting essentially of butadiene at the top of said second column; and rectifying this last vapor stream to recover pure butadiene.

Abstract: In the extractive distillation of C.sub.5 hydrocarbons with different degrees of unsaturated using acetonitrile, an increase in the selectivity of acetonitrile is obtained when also using with acetonitrile small amounts of at least one compound selected from the group consisting of dimethylformamide, dimethylsulfoxide, morpholine, furfural, N-methylpyrrolidone, 3-methoxypropionitrile, gamma-butyrolactone, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and diethylene glycol monoethyl ether.

Abstract: Formic acid is removed from acetic acid substantially free of halide impurities but containing small amounts of formic acid by contacting the acid with a compound of hexavalent chromium and recovering the purified acid from the resulting mixture by distillation, ion-exchange, or the like. In a preferred embodiment, the acid to be purified is distilled in the presence of a solution of the hexavalent chromium compound, the purified acid being obtained as the overhead product while the bottoms stream contains the reduced chromium compound. With the preferred chromium trioxide as treating agent, this compound can be recovered for re-use by adding a strong mineral acid to the bottoms stream from the distillation, electrolytically oxidizing the chromium compound contained therein, and separating chromium trioxide from the strong mineral acid solution.

Abstract: Ethylene glycol or 1,2-propylene glycol contained in mixtures with lower carboxylate esters of the glycol are separated from such mixtures by fractional distillation of the mixtures with the addition to the lower portion of the distillation zone of aqueous formic acid and/or acetic acid.

Abstract: A multi-stage process for the solvent extraction of butadiene from a mixed feed stock containing butadiene, C-4 saturated and olefinic hydrocarbons and acetylenic compounds is disclosed wherein the feed stock is contacted with N-formyl morpholine and C-4 saturated and olefinic hydrocarbons are separated therefrom in a first stage and, in a second stage, the solvent and acetylenic compounds present in the feed stock are respectively separated from one another.

Abstract: Fluorosilicic acid solutions, which normally undergo decomposition when distilled, thereby creating unwanted forms of SiO.sub.2, are rendered stable during distillation by providing in the fluorosilicic acid solution an amount of HF which is at least about 10 parts of HF per 36 parts of H.sub.2 SiF.sub.6 and an amount of H.sub.2 O which is at least about 54 parts of H.sub.2 O per 36 parts of H.sub.2 SiF.sub.6. The mixture is distilled to remove any excess H.sub.2 O and excess HF that is present, without encountering formation of SiO.sub.2, until an azeotropic solution containing about 36% H.sub.2 SiF.sub.6, about 10% HF and about 54% H.sub.2 O is reached. The ternary azeotrope, being of constant quality and concentration, is more suitable for use in various processes, such as processes for making fumed SiO.sub.2, than H.sub.2 SiF.sub.6 solutions which are not of constant quality or concentration.

Abstract: A process for separating lower-boiling chlorohydrocarbons and water from neutralized crude chlorohydrocarbons having at least two carbon atoms, which comprises fractionally distilling the crude chlorohydrocarbons in a fractionating column, thereby obtaining a fraction A containing the desired product which is withdrawn at the bottom of the column practically free of impurities, and a fraction B, comprising water, impurities having a lower boiling point, and entrained amounts of the desired chlorohydrocarbon, withdrawing said fraction B from the top of the column and, while still in gaseous state, neutralizing fraction B with an aqueous solution of a mixture of basic compounds, thereby avoiding corrosion of the apparatus, and thereafter subjecting the gaseous fraction to stepwise condensation with recovery of the entrained portions of said chlorohydrocarbon by returning them to the fractionating column, while separately removing water and undesirable impurities.

Abstract: An improvement in the process for removing vinyl chloride from a water-polyvinyl chloride slurry, which contains unreacted vinyl chloride, by steam distillation is disclosed. In many instances, steam distillation of the slurry results in an increase in the number of gels or fish eyes. The improvement comprises conducting the steam distillation in the presence of a minor, but effective, amount of an alkali metal sulfite or carbonate. The improved process results in a polyvinyl chloride having no substantial increase in, or a reduced amount of, gels or fish eyes, while still having good heat stability and porosity properties.

Abstract: In a process for reacting an aromatic or hydroaromatic alicyclic or heterocyclic dicarboxylic acid or its anhydride with an aliphatic or aromatic alicyclic or heterocyclic mono- or di-amine to produce an N-substituted dicarboxylic acid imide with a splitting off of water, the improvement of carrying out the reaction in a liquid solvent mixture consisting essentially of a non-polar organic solvent and a strongly polar organic solvent which together form a ternary azeotrope with water at reaction temperatures between about 40.degree.C. and 160.degree.C. The imide products are generally known for use as intermediates and final products in a number of industries.