Abstract: Impure 2,6-diisopropylphenol (DIP) is purified by use of a distillation process in which a single distillation column is used. The process comprises: (a) subjecting the impure DIP to a first continuous distillation in the column in an inert environment to distill off lower boiling components and produce first column bottoms enriched in DIP; (b) collecting, cooling and storing the first column bottoms while continuously maintaining them in an inert environment; (c) discontinuing the first continuous distillation; (d) subjecting the first column bottoms to a second continuous distillation in an inert environment in the same column to produce a second overhead distillate composed of purified DIP. The process avoids the formation in the distilling mixtures of dose boiling impurities due to seepage of air through standard pipe flanges and fittings and consequent oxidation reactions which occur under the conditions needed for batch distillations conducted in typical industrial distillation facilities.

Abstract: A process for preparing essentially pure 3-chlorophthalic anhydride from a mixture in which 3-chlorophthalic anhydride is present in addition to 4,5-dichlorophthalic anhydride, which involves first distilling off a mixture of 3-chlorophthalic anhydride and 4,5-dichlorophthalic anhydride, so that the obtained bottoms is essentially free of 4,5-dichlorophthalic anhydride, and then by distillation of the obtained bottoms, recovering 3-chlorophthalic anhydride in a second distillation step. The starting mixture is preferably prepared without solvent in a melt by incomplete chlorination of phthalic anhydride using FeCl.sub.3 as a catalyst.

Abstract: An extractive distillation process using a high boiling polyol such as glycerol is employed for separating high purity catechol, 3-methylcatechol and 4-methylcatechol from a high boiling, pitch-like dihydric phenol fraction. Fractional distillation first separates an impure overhead mixture of the catechol and 3-methylcatechol and an impure 4-methylcatechol bottoms. The impure overhead is extractively distilled to remove impurities and then extractively distilled again to separate the catechol and 3-methylcatechol. This produces a pure overhead of 3-methylcatechol and a bottoms of catechol and polyol which is distilled to recover the catechol and recycle the polyol. The impure 4-methylcatechol is distilled to remove residual material and then extractively distilled to remove impurities. The resulting mixture of 4-methylcatechol and polyol is distilled to recover the pure 4-methylcatechol and to recycle the polyol.

Abstract: An apparatus and method for treating chemical production plant process condensate such that a contaminant-rich stream and a relatively pure aqueous stream is separately recoverable from the condensate, wherein the contaminants are substantially removed from the condensate by steam stripping and subsequent rectification in a relatively low pressure stripping/rectification tower. The tower overhead is then condensed, and any non-condensed gases are subjected to water scrubbing to further recover contaminates from the non-condensed gas. A portion of the condensed overhead and scrubbing water containing contaminates is returned to the top of the rectification section of the tower as reflux and the balance being withdrawn as a concentrated stream for reuse in the plant. The apparatus may be used in conjunction with existing low pressure equipment, avoiding costly major modifications, and is particularly adapted to use in conjunction with ammonia and methanol plants.

Abstract: Vinyl formate containing formic acid, acetaldehyde and water following synthesis is separated from formic acid and water in a first distillation stage and from acetaldehyde in a second stage to give pure vinyl formate.

Abstract: A method for separating boric acid from a liquid, especially liquid waste obtained from a nuclear power plant. In the method, the waste solution containing the boric acid is contacted with steam in a reactor so that the boric acid evaporates from the liquid and passes into the steam vapor phase. Consequently, the radioactive wastes which are not evaporated with the steam remain in the waste water while the boric acid is removed from the waste water when it passes into the vapor or steam phase. The boric acid can then be separated and recovered from the steam by means of a distillation and fractionating column or a wash column. By removing the boric acid from the liquid waste, it is possible to obtain concentrated radioactive waste having a reduced volume due to the absence of boric acid in the waste.

Abstract: An apparatus and method for treating chemical production plant process condensate such that a contaminant-rich stream and a relatively pure aqueous stream is separately recoverable from the condensate, wherein the contaminants are substantially removed from the condensate by steam stripping and subsequent rectification in a relatively low pressure stripping/rectification tower. The tower overhead is then condensed with a portion of the condensed overhead being returned to the top of the rectification section of the tower as reflux and the balance being withdrawn as a concentrated stream for reuse in the plant. In a second embodiment, separate stripping and rectification towers operate in series whereby the overhead of the stripping tower is delivered to the lower section of the rectification tower and the rectification bottoms are returned to the top of the stripping tower.

Abstract: The present invention provides a method for separating boric acid from a liquid, especially liquid waste obtained from a nuclear power plant. In the process, the waste solution containing the boric acid is contacted with steam in a reactor so that the boric acid evaporates from the liquid and passes into the steam vapor phase. Consequently, the radioactive wastes which are not evaporated with the steam remain in the waste water while the boric acid is removed from the waste water when it passes into the vapor or steam phase. The boric acid can then be separated and recovered from the steam by means of a distillation and fractionating column or a wash column. By removing the boric acid from the liquid waste, it is possible to obtain concentrated radioactive waste having a reduced volume due to the absence of boric acid in the waste.

Abstract: An apparatus and method for treating chemical production plant process condensate such that a contaminant-rich stream and a relatively pure aqueous stream is separately recoverable from the condensate, wherein the contaminants are substantially removed from the condensate by steam stripping and subsequent rectification in a relatively low pressure stripping/rectification tower. The tower overhead is then condensed with a portion of the condensed overhead being returned to the top of the rectification section of the tower as reflux and the balance being withdrawn as a concentrated stream for reuse in the plant. In a second embodiment, separate stripping and rectification towers operate in series whereby the overhead of the stripping tower is delivered to the lower section of the rectification tower and the rectification bottoms are returned to the top of the stripping tower.

Abstract: For separating ETBE and ethanol the following principal stages are employed:(1) Extraction of ethanol by water, the raffinate being ETBE saturated in water and the extract an ethanol/water mixture containing a small proportion of ETBE;(2) Concentration of the above mixture, the distillate being a mixture close to the ethanol/water azeotrope in composition and containing a very small proportion of ETBE;(3) Heteroazeotropic distillation of this distillate in two coupled columns with an overhead decanter, this distillation using ETBE as azeotroping agent; the residue of the first column being ethanol which is ca. 99% by mole and the residue of the second column being practically pure water, this water and the water recovered during the concentration stage being used as extraction solvent in stage (1).Stage (3) may be an ethanol dehydration unit using ETBE as dehydrating agent.

Abstract: The invention generally relates to a process for the purification of a component of a binary azeotrope in which the composition of the azeotrope changes by about 10 mole percent with pressure comprising:(a) subjecting a binary azeotrope to a distillation step in which most of one of the binary components is removed as distillate (distillate 1) with the bottoms (bottoms 1) enriched in the other component;(b) subjecting distillate 1 to at least one additional distillation step conducted at a different pressure in which most of the component recovered as bottoms 1 is removed as distillate 2 with the bottoms 2 enriched in the component enriched in distillate 1;(c) optionally repeating step (b) as many times as desired; and(d) recovering the desired purified component.The invention is particularly useful in the purification of pentafluoroethane in a pentafluoroethane/chloropentafluoroethane azeotrope.

Abstract: Impure propylene oxide is purified by a distillation process wherein it is (a) extractively distilled in a first column using a C.sub.2 to C.sub.6 alkylene glycol extractive distillation agent to form a first overhead fraction comprising propylene oxide, C.sub.5 -C.sub.7 hydrocarbons methanol, water and oxygen-containing impurities, (b) wherein the first overhead fraction is separated in a second column into a second overhead fraction comprising most of the pentanes, pentenes and oxygen-containing impurities and a partially purified propylene oxide bottoms fraction comprising propylene oxide, hexenes, hexanes, and only residual quantities of pentenes and pentanes, (c) wherein the partially purified bottoms fraction is extracting distilled in a third column using a C.sub.7 -C.sub.

Abstract: A stream of raw phenol, coming from the acidic cracking of cumene hydroperoxide, is purified by a process of extractive distillation carried out in the presence of acetophenone.

Abstract: The separation of ethyl tertiobutyl ether from mixtures with ethanol is based on heteroazeotropic distillation with water as the entrainer using two distillation columns, coupled with an overhead decanter. Purified ethanol is collected from the bottom of the first column and purified ETBE from the bottom of the second column. The separation method may be incorporated into an ETBE production unit in which isobutene (contained in a C.sub.4 -cut from steam cracking, catalytic cracking, or dehydrogenation of isobutane) is etherified by ethanol. Ethanol separated from the ETBE is then recycled to the etherification zone.

Abstract: Purification of crude sulfolane to remove color imparting and turbidity imparting impurities therefrom is achieved by a two-pass distillation process wherein purified sulfolane is withdrawn from the bottom of a column in the second distillation pass.

Abstract: The present invention provides a continuous method of purifying eicosapentaenoic acid and esters of eicosapentanoic acid, comprising (a) fractionally distilling a starting mixture containing eicosapentaenoic acid or esters of eicosapentaenoic acid using a system of at least three distillation columns connected in flow arrangement to separate a fraction containing eicosapentaenoic acid or esters of eicosapentaenoic acid and other C.sub.20 fatty acids from a fraction containing lower-number carbon fatty acids and from a fraction containing higher-number carbon fatty acids, and (b) continuously collecting the fraction containing eicosapentaenoic acid or esters of eicosapentaenoic acid, wherein the pressure in the distillation columns is maintained at 10 Torr or below and wherein the bottom temperature of the distillation columns is maintained at 210.degree. C. or below.

Abstract: A distillation process for the preparation of purified concentrated BDO.High boiling impurities, including color formers, precursors of color formers and tar formers are removed from the BDO early in the process and under mild conditions.

Abstract: Disclosed is a process for the recovery of purified hydroxypivalyl hydroxypivalate (HPHP) from a crude, HPHP containing material containing inorganic catalyst residues and low-boiling and high-boiling (with respect to the boiling point of HPHP) impurities. The purification process employs two distillation zones, a first distillation zone wherein inorganic and high-boiling impurities are removed and a second distillation zone wherein low- and high-boiling impurities are removed.

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: The present invention provides a method for the recover of a solvent used in the production of a polyarylene sulfide according to which the deterioration of the solvent is low and the recovery rate is high, wherein a mixed liquid, mainly composed of the solvent used in the production of the polyarylene sulfide, and generated from the process of producing the polyarylene sulfide, is subjected to a flash evaporating operation to separate the mixed liquid into a flashed vapor (A) and a flashed residue (B), and then the flashed vapor is rectified (A).

Abstract: A distillation tower (1) has a plurality of liquid sidestream lines (5, 6, 7) and a multi-stage sidestream stripper (13) which includes a respective stripping section (14, 15, 16) for each sidestream line housed in a common, upright, cylindrical shell (28) which allows vapor to pass freely from each stage to the one above. Partial vaporization of each sidestream is achieved by applying a vacuum to the top of the stripper shell (point 21) and/or introducing strip gas at the bottom (point 20). Because the vapor passes serially through the stripping sections from the bottom of the stripper (13) to the top, the need to supply strip gas separately to the stripping sections and/or apply vacuum individually is avoided. The separation between the sidestream products is improved by including, in each stage, a rectification zone (22, 23, 24) positioned above the stripping section.

Abstract: For the separation of tert. butyl ethyl ether from mixtures with ethanol, there are provided two distillation stages, the first being carried out at a pressure p.sub.1 equal to or higher than 1 bar, the second at a pressure p.sub.2 below p.sub.1 by a value .DELTA.p or 0.5 to 12 bars, p.sub.2 then being 0.5 to 10 bars. The second column distillate is partly supplied as reflux to the head of the second column and is in part recycled to the head of the first column. The purified TBEE is collected at the bottom of the first column and the purified ethanol at the bottom of the second column.This separation process can be integrated into a TBEE production unit comprising etherification by ethanol of the isobutylene contained in a C.sub.4 fraction from a catalytic cracking or steam cracking stage. The ethanol separated from the TBEE is then recycled to the etherification zone.

Abstract: An alcohol such as methanol is reacted with carbon monoxide in a liquid reaction medium containing a rhodium catalyst stabilized with an iodide salt, especially lithium iodide, along with alkyl iodide such as methyl iodide and alkyl acetate such as methyl acetate in specified proportions. With a finite concentration of water in the reaction medium the product is the carboxylic acid instead of, for example, the anhydride. The present reaction system not only provides an acid product of unusually low water content at unexpectedly favorable reaction rates but also, whether the water content is low or, as in the case of prior-art acetic acid technology, relatively high, is characterized by unexpectedly high catalyst stability; i.e., it is resistant to catalyst precipitation out of the reaction medium.

Abstract: The process for rectification of phenol prepared from crude phenol being the product of decomposition of cumene hydroperoxide and having previously been distilled to remove large portions of acetone, cumene and alpha methylstyrene which includes:feeding the column overhead vapors to a condenser, thereby condensing a major portion of the overhead vapors;withdrawing a small portion of the overhead vapors from the condenser while still in a vapor state, the small portion being relatively enriched in lights and laden with light acids;returning the condensate from the condenser to the phenol distillation column as reflux; andwithdrawing product phenol from at least one-theoretical stage below the top of the phenol distillation column, the product phenol having improved clarity when dispersed in water, clarity being at least 93 percent light transmission as measured by an electrophotometer in a water light test.

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: A process for the recovery of methoxyisopropylamine from the reaction of methoxyisopropanol and ammonia under amination conditions. Water is produced as a byproduct and in the distillation separation an azeotrope is formed which includes about 14% water and 86% methoxyisopropylamine. The improvement for enhancing separation of the azeotrope includes initially distilling the mixture of methoxyisopropylamine, methoxyisopropanol and water under sufficient elevated pressure wherein an azeotrope of water and methoxyisopropylamine overhead and an essentially water free bottoms of methoxyisopropylamine and methoxyisopropanol are formed. The overhead from this initial distillation column is charged to a second distillation column operated at reduced pressure wherein an organic free bottoms containing primarily water is obtained.

Abstract: A process for the purification of crude benzoic acid obtained by the catalytic oxidation of toluene in the liquid phase, which is contaminated with impurities including phthalic acid and benzylbenzoate, the process involves distilling the crude benzoic acid in a first distillation in the presence of an aliphatic amine or a mixture of aliphatic amines of the formulaHNR.sup.1 R.sup.2whereinR.sup.1 represents hydrogen or a straight-chain or branched hydroxyalkyl or aminoalkyl radical with 1 to 6 carbon atoms andR.sup.2 represents a straight-chain or branched hydroxyalkyl or aminoalkyl radical with 1 to 6 carbon atoms,and/or the salts of these amines, recovering from this distillation (a) a purified benzoic acid and (b) a benzylbenzoate containing residue, working up the residue by a second distillation and chlorinating the distillate resulting from this second distillation to give a benzoylchloride virtually free of benzonitrile.

Abstract: A thermally-integrated extractive distillation process for recovering anhydrous ethanol from fermentation or synthetic feedstocks has a distillation train of four columns. Two columns are preconcentrators operated in parallel. The remaining columns are an extractive distillation dehydrating tower, and an entrainer-recovery column. The two preconcentrators and the dehydrating tower are operated at three successively increasing pressures so that the condensing vapors of the overhead product of the dehydrating tower supply the necessary heat to the reboiler of the intermediate-pressure preconcentrator. The overhead vapors of this preconcentrator are, in turn, used to supply the required heat to the reboiler of the lowest-pressure preconcentrator. The bottom product from each preconcentrator is used to preheat the dilute feed. Additional energy savings are accomplished by the appropriate heat exchange between the various feeds, overheads, and bottoms.

Abstract: An alcohol such as methanol is reacted with carbon monoxide in a liquid reaction medium containing a rhodium catalyst stabilized with an iodide salt, especially lithium iodide, along with alkyl iodide such as methyl iodide and alkyl acetate such as methyl acetate in specified proportions. With a finite concentration of water in the reaction medium the product is the carboxylic acid instead of, for example, the anhydride. The present reaction system not only provides an acid product of unusually low water content at unexpectedly favorable reaction rates but also, whether the water content is low or, as in the case of prior-art acetic acid technology, relatively high, is characterized by unexpectedly high catalyst stability; i.e., it is resistant to catalyst precipitation out of the reaction medium.

Abstract: Small amounts of a medium-boiling fraction are removed from a liquid mixture by distillation using a distillation column (main column) having a rectifying part and a stripping part, the liquid mixture containing relatively large amounts of lower-boiling and higher-boiling components, and the rectifying part being connected to the upper end of a second distillation column (side column) and the stripping part to the lower end of the said column, and the medium-boiling fraction being removed in vapor or liquid form from its middle section, by a process in which the concentration of the medium-boiling fraction in the liquid mixture is less than 2%, preferably less than 0.1%, and the amount of vapor passed into the lower end of the side column from the main column is 1-20%, preferably 3-10%, based on the amount of vapor in the main column at the relevant point.

Abstract: The carbonylation of an alcohol to produce a carboxylic acid, especially methanol to produce acetic acid, in a low water reaction medium containing a rhodium catalyst stabilized with an iodide salt, especially lithium iodide, along with alkyl iodide such as methyl iodide and alkyl acetate such as methyl acetate in specified proportions is improved by the addition of hydrogen in the feed gas to the low water reaction medium to obtain a reactor hydrogen partial pressure of at least about 4 psi. The presence of hydrogen in the reaction medium increases significantly the carbonylation reaction rate and reduces formation of byproduct carbon dioxide. The present reaction system not only provides an acid product of unusually low water content at unexpectedly favorable reaction rates but also, whether the water content is low or, as in the case of prior-art acetic acid technology, relatively high, is characterized by unexpectedly high catalyst stability; i.e.

Abstract: An apparatus and method for reprocessing waste piranha containing contaminated H.sub.2 SO.sub.4 from, for example, a semiconductor processing operation is described. The apparatus and method include a first distillation flask which are maintained under a substantial vacuum. The first distillation flask includes a first column with a column packing means and a reflux means to retard loss of H.sub.2 SO.sub.4 in the first distillation. The second distillation flask boils off substantially pure H.sub.2 SO.sub.4 through a column which is coupled to a condenser which condenses substantially pure H.sub.2 SO.sub.4.

Abstract: An improved process for separating ethylene-oxide from formaldehyde and acetaldehyde in contaminated ethylene oxide, the process involves introducing the contaminated ethylene oxide into a reflux column and distilling the contaminated ethylene oxide under conditions such that the fluid stream leaving the bottom of the reflux column contains the water present in the contaminated ethylene oxide and the ethylene oxide in amounts corresponding, on a weight basis, to 0.15 to 3 times the weight of the water, and the ethylene oxide resulting from the separation of the formaldehyde and acetaldehyde leaves the column at its top.

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: The process for production of an aromate concentrate for use as a blending component for gasification fuel includes subjecting another feed hydrocarbon mixture to an extractive distillation using N-substituted morpholines as selective solvent in a extractive distillation column. Low-boiling non-aromates with a boiling range up to about 105.degree. C. practically completely and higher-boiling non-aromates with a boiling range between about 105.degree. and 160.degree. C. to a substantial extent are discharged as a raffinate from the top of the extractive distillation column. The extract bottoms from the extractive distillation are fed to a solvent stripping column where the solvent is at least partially recovered from other hydrocarbons. To eliminate condensation and polymerization products due to components with a boiling point over 170.degree. C.

Abstract: Tetrahydrofuran is recovered by a two stage distillation procedure from a crude hydrogenation product resulting from vapor phase hydrogenation of diethyl maleate and containing water, ethanol and a minor amount of n-butanol, and possibly also dissolved hydrogen, in addition to butane-1,4-diol, gamma-butyrolactone and "heavies" such as diethyl ethoxysuccinate. In the first distillation stage, conveniently operated substantially at atmospheric pressure, ethanol, water, and tetrahydrofuran are recovered as overhead product, are condensed to separate the condensible components from a hydrogen stream which can be vented, and then redistilled in the presence of a molar excess of a hydroxylic solvent containing at least two hydroxyl groups, such as butane-1,4-diol, in a second distillation zone.

Abstract: The process and the device according to the invention relate to the introduction, at a stable, known flow rate, of sublimable tetrachloride into a column for continuous extractive distillation under pressure of the chlorides. The sublimable tetrachloride is dissolved in a hot dissolver in a liquid solvent such as KAlCl.sub.4, and is then recirculated by pump at a stable, known flow rate into an evaporator connected to the column. The solution is then heated in an evaporator in order to sublime the majority of the product which it contains, the sublimed vapors thus passing into the column at a stable, known flow rate. The process according to the invention is adapted, in particular, to a plant for the production of ArCl.sub.4 of nulear purity and of HfCl.sub.4.

Abstract: Disclosed is a method for separating and concentrating an organic component having a lower boiling point than water from an aqueous solution containing the organic component which comprises the steps of (1) bringing an aqueous solution containing an organic component having a lower boiling point than water into contact with one surface of a hydrophobic porous membrane, continuously or intermittently evacuating the side of the porous membrane opposite to the aqueous solution to obtain a concentrated vapor of the organic component, and liquefying the vapor; and (2) bringing the resulting concentrated aqueous solution into contact with one surface of a hydrophobic nonporous membrane, evacuating the side of the non-porous membrane opposite to the concentrated aqueous solution to obtain a further concentrated vapor of the organic component, and liquefying the vapor.

Abstract: 1,3-Butadiene is isolated from a C.sub.4 -hydrocarbon mixture containing 1,3-butadiene and small amount of propyne and C.sub.5 -hydrocarbons by extractive distillation with a selective solvent and subsequent distillative purification of the crude 1,3-butadiene obtained in the extractive distillation.

Abstract: A fractional distillation system is provided for fractionating unequal liquid mixtures with lower heat throughput and lower energy consumption. For mixtures in which the heavy fraction is predominant (FIG. 1), a stripper (2) pre-fractionates part of the mixture at lower pressure and at no extra energy cost by being reboiled by an intermediate condenser (3). The pre-fractionator temperature range is preferably nested within (overlapped by) the distillation column (6) temperature range.

Abstract: In the purification of ethylene oxide from an ethylene oxide-containing reaction formation gas produced by catalytic gas-phase oxidation of ethylene with a molecular oxygen containing gas, external thermal energy required for heating an ethylene oxide refiner is economized by a method which utilizes the diffusate obtained from the top of an ethylene oxide stripper as a heat source for the refiner. Further, the bottom liquid of the stripper can be used as a heat source for ethylene oxide refiner and/or a light ends stripper.

Abstract: A continuous process is described for the production of a substantially acid free dialkyl maleate, for example diethyl maleate, from a feed stream containing a major amount of dialkyl maleate and a minor amount of the corresponding monoalkyl maleate. This comprises continuously distilling the feed stream in a primary distillation zone, which can comprise a single distillation column or a series of distillation columns connected in series, so as to give (i) a bottom fraction containing monoalkyl maleate and dialkyl maleate in admixture, (ii) a vaporous fraction comprising alkanol, and (iii) an intermediate fraction that is substantially free from alkanol and comprises a major proportion of diethyl maleate and a minor proportion of maleic anhydride. The intermediate fraction (iii) is redistilled in a secondary distillation zone to yield (i) an overhead fraction containing maleic anhydride and (ii) a bottom fraction containing substantially acid free dialkyl maleate.

Abstract: A method of producing substantially pure dialkyl maleate by separating monoalkyl maleate from dialkyl maleate in a short residence time distillation zone while minimizing reversion of the monoalkyl maleate to alkanol and maleic anhydride and without having to neutralize the monoalkyl maleate.

Abstract: An aqueous effluent is supplied to a stripping column (total stripping column) from which a mixture that is rich in NH.sub.3, CO.sub.2 and H.sub.2 S is withdrawn as a head product. In at least one additional stripping column the mixture is separated into a mixture which is rich in NH.sub.3 and a mixture which is rich in the sour gaes CO.sub.2 and H.sub.2 S. The mixture which is rich in NH.sub.3 is scrubbed with liquid ammonia. The overhead product from the total stripping column is cooled in a condenser under a pressure of 1 to 7 bars and is thus transformed into a liquid phase to such an extent that the liquid phase contains 70 to 100% of the NH.sub.3 which has been supplied to the condenser. The liquid phase is supplied at a temperature of 30.degree. to 90.degree. C. to a second stripping column (NH.sub.3 stripping column), which is operated under a pressure of 1 to 4 bars and from which a gas mixture that is rich in NH.sub.3 is withdrawn as a head product.

Abstract: A process for removing by product acetone from reaction mixtures obtained by reacting methyl acetate and/or dimethylether with carbon monoxide at elevated temperatures to obtain acetic anhydride in the presence of a catalyst system consisting essentially of carbonyl complexes of noble metals belonging to group VIII of the Periodic System of the elements, acetic acid, an organophosphorus or organonitrogen compound, and methyl iodide whereby the acetone obtained as a by-product during the reaction is subjected to condensation at temperatures of 50.degree. to 250.degree. C., under pressures of 0.01 to 150 bars and at a molar ratio as above defined for the catalyst system constituent of 1:(25-500):(10-100):(15-150) so as to obtain predominantly higher-boiling secondary products to be distillatively separated in a successive distillation zone together with volatile constituents of the catalyst system.

Abstract: A process for extracting pure components from a multi-component system, said system comprising a mixture of at least two solids or liquids in a supercritical fluid at constant pressure, which involves making use of the cross-over pressure points of the components which comprise the system.

Abstract: Preparation and recovery of 1-t-butoxy-2-propanol in a high state of purity from a crude etherification reaction product obtained by reaction of isobutylene with propylene glycol in the presence of a solid resin etherification catalyst is disclosed. The crude reaction product is distilled to obtain a 1-t-butoxy-2-propanol-containing distillate, thereby leaving propylene glycol as bottoms; the condensed distillate is then further distilled to separate 1-t-butoxy-2-propanol as an overhead product from higher boiling materials.

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: In the distillation of fresh water from sea water, the sea water is passed ownwardly in a falling film evaporator through a multiplicity of vertical tube evaporator (VTE) stages and multiple stage flash (MSF) evaporators. After the sea water passes through the first VTE stage where it forms a liquid component and a steam component, the liquid component is distributed evenly into the next VTE stage while the steam component enters an adjoining MSF stage. Condensed fresh water flows downwardly from one MSF stage to the next and experiences flash evaporation. The sea water or brine component and the fresh water distillate flow downwardly through the VTE and MSF stages so that the brine component can be removed from the final VTE stage and the fresh water distillate from the final MSF stage.

Abstract: A method of processing fermented liquid comprising(a) feeding said fermented liquid into a vacuum vaporizer, (b) heating the feed in said vaporizer to separate it into a vapor and a concentrated liquid fraction, (c) recycling said vapor to said vaporizer by compression so as to achieve heat-exchange with said feed therein thereby generating a new vapor and a condensate fraction; said condensate being discharged as a distillate, (d) supplying the remaining compressed vapor to a multistage distilling column, (e) separating said compressed vapor into two fractions, one with a higher boiling point than the other, within said distilling column, (f) condensing said distillate with the lower boiling point to yield an alcohol-rich distillate, and (g) discharging said fraction with the higher boiling point as a bottom residue, and a processor therefor, thereby discharging to the outside the low COD-liquid alone and recovering useful substances such as drinkable alcohol, livestocks feed and antibiotic substances.