Abstract: A liquid containing a contaminant such as water or polymeric solids is purified. Purification of a liquid containing a contaminant is enhanced by the use of second fractionating column in conjunction with a first fractionating column to recover a portion of the liquid to be purified from the kettle product of the first column. Vapor from a second fractionating column is used to control the total energy input to a first fractionating column.

Abstract: A process is disclosed for separating low molecular weight alcohols, especially ethanol, from aqueous mixtures. The process involves subjecting alcohol-water mixtures to extraction and/or extractive distillation procedures. Extractive solvents useful for the process of this invention include phenols having at least six carbon atoms and a boiling point between about 180.degree. C. and about 350.degree. C.

Abstract: A method for improving the separation of a feed into a distillate and a bottoms product is disclosed. The subject invention includes a first distillation zone and a second distillation zone, each having rectification and stripping zones. Bottoms from the first stripping zone are passed into the second distillation zone. Distillate from the second rectification zone is removed utilizing a fluid evacuation means and returned to the first stripping zone.

Abstract: Process and apparatus for extracting an organic liquid from an organic liquid solute/solvent mixture. The mixture is contacted with a fluid extractant which is at a temperature and pressure to render the extractant a solvent for the solute but not for the solvent. The resulting fluid extract of the solute is then depressurized to give a still feed which is distilled to form still overhead vapors and liquid still bottoms. The enthalpy required to effect this distillation is provided by compressing the still overhead vapors to heat them and indirectly to heat the still feed. The process is particularly suitable for separating mixtures which form azeotropes, e.g., oxygenated hydrocarbon/water mixtures. The energy required in this process is much less than that required to separate such mixtures by conventional distillation techniques.

Abstract: A process permitting hazard free purification by distillation of compounds which are distillable per se but which present the risk of explosive decomposition under the effect of elevated temperatures. A desensitizing substance is added to the compounds to be distilled.Aliphatic alcohols for instance are suitable additives for alkinols.Examples are provided for the distillation of butinediol-1,4 together with the additive glycerin.

Abstract: Process and apparatus for extracting an organic liquid from an organic liquid solute/solvent mixture. The mixture is contacted with a fluid extractant which is at a temperature and pressure to render the extractant a solvent for the solute but not for the solvent. The resulting fluid extract of the solute is then depressurized to give a still feed which is distilled to form still overhead vapors and liquid still bottoms. The enthalpy required to effect this distillation is provided by compressing the still overhead vapors to heat them and indirectly to heat the still feed. The process is particularly suitable for separating mixtures which form azeotropes, e.g., oxygenated hydrocarbon/water mixtures. The energy required in this process is much less than that required to separate such mixtures by conventional distillation techniques.

Abstract: Process for working up aqueous nitric acid which is of a concentration above the azeotropic concentration and contains organic compounds in solution for suspension wherein said nitric acid of a concentration about the azeotropic concentration is distilled off in one or more rectification steps until the azeotropic nitric acid is obtained. In the process, certain specified ratios of nitric acid and water to organic constituents must be maintained.

Abstract: In a process for producing acrylic acid which comprises contacting with water an acrylic acid-containing reaction product gas which has been obtained by the catalytic vapor phase oxidation of an olefinic compound of a general formula, CH.sub.2 .dbd.CHX, wherein X represents at least one group selected from the group consisting of CH.sub.

Abstract: The invention relates to a process for the production of .epsilon.-caprolactone having a purity of 99.9% and increased color and storage stability which comprises feeding .epsilon.-caprolactone, which has been made by reacting cyclohexanone with a solution of a percarboxylic acid, into a first distillation unit, operating at 0.1 to 500 mbars and drawing off as the top product a mixture consisting of .epsilon.-caprolactone and lower-boiling impurities, feeding the bottom product of said first distillation unit into a second distillation unit, operating at 0.1 to 500 mbars and then drawing off the pure .epsilon.-caprolactone as the top product. The .epsilon.-caprolactone is useful as an intermediate for the production of known useful compounds such as polyesterols which are subsequently converted to polyurethanes.

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

Abstract: In a process for the preparation of fiber-grade terephthalic acid from intermediate stage crude dimethyl terephthalate, the crude dimethyl terephthalate, which has a limited content of intermediate oxidation products including a content of terephthalaldehydic acid methyl ester of up to 0.1% by weight based on the weight of the crude dimethyl terephthalate, is hydrolyzed with water at a weight ratio of the crude dimethyl terephthalate to water of between 3:1 and 0.1:1 and at a temperature between 140.degree. C. and 350.degree. C. and under a pressure required to maintain a liquid phase (e.g., from 6 to 200 bars) to produce a reaction mixture containing crystalline fiber-grade terephtalic acid and thereafter the terephthalic acid is recovered from the reaction mixture.

Abstract: A mechanical energy conversion method and system for the restoration of dissipated heat energy, contained in natural or artificial water bodies at or near ambient temperatures, to industrial process heat, mainly in the form of steam up to 200.degree.-400.degree. C. The sensible heat contained in a water body is concentrated as latent heat in low pressure water vapor which is thermo-compressed by steam ejection to an intermediate pressure level, wherefrom mechanical compression takes over, generating highly superheated output steam. The ejecting steam is not generated in a boiler, but is continuously regenerated by the compressor and routed back for repeated ejection. The compressor is driven by a heat engine whose reject heat is collected and upgraded as well. The output of heat energy is essentially equal to the sum of the heating value of the fuel consumed and the intake of latent heat and amounts thus to substantially more than the heating value of the fuel alone.

Abstract: In recovering the multi-solvent portion of the oil solvent mixture in a solvent dewaxing process, decomposition of a thermally unstable, lower boiling solvent component is substantially avoided by recovering the solvent in a series of controlled evaporations whereby the major portion of the lower boiling solvent component is removed from the mixture prior to the removal of the remaining portion of the solvent. The solvent removal may be conducted in a high pressure evaporator having an upper section and a lower section separated by an annular tray.

Abstract: Ethyl acetate and an excess of ethylene glycol monoethyl ether are subjected to ester-interchange reaction at a temperature not exceeding 100.degree. C. in the presence of a strongly acidic cation exchange resin as a catalyst. The resulting reaction mixture is distilled to recover the ethylene glycol monoethyl ether acetate formed. The unchanged reactants are recycled to the reaction zone for re-use, and the by-product ethanol is recovered in a highly pure form. This method can be continuously performed easily and effectively without the need to separate the catalyst or to employ complex distilling steps and without involving other difficulties.

Abstract: Water containing dissolved compounds is preheated, and is then pressurized in stages of water pressure, while receiving a quantum of steam. Scale-forming compounds in the water are thermally precipitated, and clarified post-thermal water is formed. This is flash vaporized in stages corresponding to the stages of water pressure, and the flashed vapors are compressed to form each said quantum of steam. Alternately, the flashed vapors themselves comprise each said quantum of steam, by being induced into the water as it flows through an eductor means. Flash-cooled, post-thermal water, substantially devoid of scale-forming compounds, is employed as such, or more generally is evaporated to form fresh water and an end concentrate of dissolved compounds.

Abstract: Aqueous saline solutions are converted in part to potable water by passing a compressed aqueous saline solution through one or more beds of contained pellets of higher temperature to heat the aqueous solution to a flash vaporization temperature, then passing the solution to one or more flash vaporization zones. Vaporized potable water from each vaporization zone is separately passed to contained bed of pellets where water is condensed and pellets heated. Simultaneously, a bed of pelletized solids is heated to supplant the highest temperature bed in the system used for heating. By selective switching of beds, the system is kept in continuous operation with a heated bed of pellets replacing the highest temperature bed previously used to heat the aqueous saline solution. The bed used for water condensation is transferred to the heating cycle for subsequent introduction to the system.

Abstract: Purified methanol is produced by distilling a water methanol mixture in (a) a first column from which is taken a product methanol stream at an upper level, weakly aqueous methanol as a side stream and water as bottoms and (b) a second column in which that weakly aqueous methanol is separated into an overhead product stream and aqueous methanol bottoms. The first column may be preceded by a preliminary volatiles-removal column. The process is economical in heat consumption, especially when methanol vapor from the second column is heat-exchanged with the feed or bottoms of the first column.

Abstract: This invention relates to a vaporizer for generating developer gas, containing ammonia, from aqueous ammonia for developing diazo copying material comprising a first vaporizer unit including a rectifying column and a column head, a gas outlet for taking off the developer gas and an inlet opening into the column head for feeding in aqueous ammonia, and a heatable, steam-generating sump vessel having a base and a residual water outlet, a second unit including a volatilizer with means for heating a base zone thereof, a residual water inlet opening in said base zone, a residual water line connecting said residual water inlet opening to said residual water outlet of said rectifying column, said residual water outlet of said rectifying column projecting upwardly in said sump vessel and having an orifice above the base thereof, said two units being arranged side by side with parallel axes in a single casing, a first connecting branch as said gas outlet for taking off the developer gas and a second connecting branch

Abstract: A process for purifying crude acrylic acid characterized in that high-purity purified acrylic acid containing little or no low boiling aldehydes is obtained by rectifying a crude acrylic acid consisting essentially of acrylic acid and containing low boiling substances such as acetaldehyde, acrolein, water and acetic acid and/or high boiling substances such as maleic acid, phenol, benzaldehyde and acrylic acid dimer, thereby removing said low boiling substances and then high boiling ones, and then stripping trace amounts of remaining low boiling aldehydes with an inert gas such as nitrogen or air at a liquid to gas molar ratio of 2 to 20.

Abstract: Water-containing glycol is heated first at atmospheric or superatmospheric pressure to partially remove water and concentrate the glycol and is then heated at subatmospheric pressure to further concentrate the glycol.

Abstract: The recovery of dimethylacylamides from solutions which are formed during the production of fibres is particularly economical if the solution is concentrated in a separating column to produce a sump product having a DMA content of 30 to 90% at pressures of more than 300 Torr, using the evaporation heat of the head product for heating the column, with the aid of a compressor and then separating the sump product which is concentrated in DMA by distillation.

Abstract: An improved process for recovering isobutylene contained in a mixture of hydrocarbons having four carbon atoms by selective extraction with an aqueous solution of sulfuric acid of a concentration of about 50 wt. % followed by separating the isobutylene-rich sulfuric acid extract by a first flash distillation of the extract and by a second physical separation of the isobutylene-enriched extract from said flashing step (which the latter physical separation is preferaby a second flash distillation at a temperature which is higher than the first and is at 75.degree. C. or less, and wherein said first flash distillation is between 10.degree. and 60.degree. C. and both distillations are preferably at a pressure between 0.5 and 1.5 bars absolute to give an isobutylene purity greater than 99.5%).

Abstract: A process for concentrating at least one of (a) individual halogenoanthraquinones (b) binary mixtures of di-halogenoanthraquinones and (c) binary mixtures of trihalogenoanthraquinones, from a mixture containing at least two halogenoanthraquinones, comprising subjecting said mixture containing at least two halogenoanthraquinones to fractional vacuum distillation in a heated rectification column having an efficiency corresponding to about 20 to 50 theoretical stages with an absolute pressure at the top of about 0.5 to 50 mm Hg and a reflux to take-off ratio of about 5/1 to 50/1.

Abstract: Process for isolating propylene glycol diacarboxylates in the preparation of propylene oxide by reaction of propylene with a solution of percarboxylic acid in an organic solvent, the boiling point of which is lower than that of the carboxylic acid which corresponds to the percarboxylic acid used as the epoxidizing agent, and higher than that of propylene oxide, separation, by distillation, of the reaction mixture which essentially contains propylene oxide, the carboxylic acid corresponding to the percarboxylic acid used as the epoxidizing agent and one or more of the by-products propyleneglycol, propylene glycol monocarboxylate and propylene glycol dicarboxylate as well as propylene and the organic solvent, into a fraction containing propylene oxide and propylene and a fraction containing the carboxylic acid, the by-products mentioned and the organic solvent and further separation of the fractions into the individual components by distillation.

Abstract: A method for the recovery of sulphur compounds, volatile alcohols such as methanol, as well as by-products such as turpentine and the like, which are formed in connection with pulping, from the blow-expansion condensates from the evaporating series of a digestery, from turpentine mother liquors, or from other liquids in a separate treatment unit. The liquids are treated in a vacuum stripping unit by means of a proportion of secondary steam which is obtained from the last step of a multi-stage evaporating plant. The excess of secondary steam is condensed by means of indirect condensation in a first surface condenser, whose exhaust vapors, together with the vapors leaving the stripping unit and with gases that are to be removed from the evaporating steps, are condensed by means of indirect condensation in a second surface condenser.

Abstract: A method for producing mechanical energy from geothermal brine in which a heat transfer fluid (HTF) is heated by direct contact with the hot geothermal brine in cocurrent flow through a series of flash stages which are maintained at successively lower pressures so that the HTF is vaporized in each stage. A working fluid is countercurrently flowed through the series of flash stages in indirect heat exchange with the vapor produced in each stage so that the vapor is condensed in each stage and the working fluid is progressively heated as it passes through the series of flash stages. The heated working fluid is utilized in a heat engine for the production of mechanical energy.

Abstract: Fluid mixture of acetone and at least one hydrocarbon containing four-carbon atoms is separated by fractional distillation at a pressure low enough to eliminate formation of an azeotrope and a corresponding temperature.

Abstract: Waste water resulting from the production of acrylonitrile by gas phase oxidation of propylene and ammonia with oxygen as washing water in the recovery section is purified by treating the waste water with 0.4 to 1 ton of steam per ton of waste water in a detoxification column attached to or following the separation column (for the separation of acetonitrile and acrylonitrile from the waste water in the acrylonitrile process) at a temperature from 100.degree. to 125.degree. C, at a pressure of 0 to 2 (gauge) atmospheres; separating the non-volatile resinous organic compounds from the thus treated waste water in an evaporator and using the vapors from the top of said evaporator to heat the said separation column and detoxification column; and optionally adding an organic amine to said distillation column or to said evaporator.

Abstract: A two-stage evaporative method for recovering polymerizable 2-pyrrolidone from alkaline aqueous solutions such as those obtained by washing the catalyst from an incompletely reacted polypyrrolidone polymerizate, includes the steps of neutralizing the base with mineral acid, removing most of the water in an initial reduced pressure evaporation and recovering the pyrrolidone from a salt/pyrrolidone slurry by vaporization under reduced pressure.

Abstract: A method of partially or totally separating chlorinated aliphatic C.sub.1 to C.sub.3 hydrocarbons from mixtures of at least two of the chlorinated hydrocarbons by extractive distillation.The mixture of the chlorinated hydrocarbons is distilled in the presence of one or more third organic compounds having a boiling point higher than that of the substances to be separated, selected from the group comprising methyl, ethyl, normal propyl and isopropyl mono and di-chloroacetates; benzyl alcohol; salicylaldehyde, benzaldehyde, n-heptanal, methylisobutylketone, tetramethylurea, .gamma.-butyrolactone; normal propyl, isopropyl, normal, secondary and tertiary butyl acetylacetates; diethyl oxalate, dimethyl succinate and preferably methyl and ethyl acetylacetates; acetic anhydride, N-formyl-morpholine, 2-chloro ethanol, hexamethylphosphotriamide, dimethyl sulphate and normal tributyl and triisobutyl phosphates.

Abstract: A system for optimal pressure control in a multistage evaporation unit comprising two or more series connected evaporation stages with at least one of the stages preceded by a heat source, where the fresh or feed solution is passed through heat exchangers in which it is heated by means of the vapors from the subsequent evaporation stages, and where a heat exchanger adapted to permit free flow of the vapor condensate through the heat exchanger inner portion or tube portion is arranged in the line through which the vapor leaves the higher-pressure evaporation stage.

Abstract: A process is provided for the removal of water from a mixture of ethylene diamine and water and for the preparation of ethylene diamine having a water content below the azeotropic equilibrium water content between ethylene diamine and water, by distilling the mixture in the presence of a distillation adjuvant comprising one or more compounds selected from the group consisting of piperazine, diethylene, triamine, hydroxethyl ethylene diamine, and aminoethyl piperazine. The adjuvant can be removed later if desired.

Abstract: Hydrocarbons having different degrees of saturation are separated by extractive distillation using selective solvent comprising a mixture of dimethylsulfone, methylethylketone and sulfolane.

Abstract: A process for obtaining isobutylene in a purity greater than 99.5% from an initial feed of relatively pure isobutylene which further has minor quantities of tertiary butyl alcohol, water, polymers of isobutylene, and cis and trans-2-butenes in an economic manner while retaining good yields of the isobutylene by distilling the initial feed to separate a significant portion of the isobutylene with a purity equal to or greater than 99.

Abstract: Aqueous solutions and suspensions of solid particles, even those containing less than one percent of organic materials, may be combusted with air, oxygen, or their mixtures in a process which provides for preheating in countercurrent batches of the raw original liquid by either open (direct contact) or closed (heat transfer surface) condensation of steam generated by multiple flash evaporations which cool earlier batches of hot liquid after the wet combustion. Excess heat may often be withdrawn from the process for power generation or other use as high pressure steam, with or without combustion gases and other non-condensibles. No pumps are necessary, liquid batches are pressurized by steam generated in the flash evaporations for which only one pressure vessel is required instead of the many in the continuous processes.

Abstract: Process for purification of crude pyromellitic acid dianhydride produced by vapor phase oxidation of 1,2,4,5-tetraalkylbenzene with an oxygen-containing gas, having a purity of more than about 95% pyromellitic acid dianhydride. In a first distillation stage, said crude pyromellitic acid dianhydride is distilled at pressure of less than about 310 Torr, and temperature of less than about 350.degree. C to distill overhead an impurities containing fraction amounting to less than about 20% of the crude introduced into the first stage, and provide a residue enriched in pyromellitic acid dianhydride. In a second distillation stage, the residue of the first stage is distilled at lower pressure and at temperature of less than about 325.degree. C to distill overhead the purified pyromellitic acid dianhydride, and provide an impurities containing residue of less than about 12% of the crude introduced into the first step.

Abstract: Glycide is prepared by reacting allyl alcohol with hydrogen peroxide in the presence of a tungsten compound as a catalysts the excess allyl alcohol and the greatest part of the water distilled off, the sump mixture obtained in the distillation is split at 110.degree.-220.degree. C. and 5 to 60 torr in a thin layer evaporator into a volatile portion which is predominantly glycide, high boiling by products and the residual part of the water and a sump portion of glycerine, polyglycerine and catalysts. The volatile liquid portion is broken into glycide, water and high boiling byproducts at 5 to 60 torr in a distillation apparatus directly connected to the thin layer evaporator.

Abstract: A process for recovering and separating substantially pure ethylphenol and substantially pure diethylbenzene from a mixture resulting from the decomposition of diethylbenzene monohydroperoxide and consisting essentially of diethylbenzene, ethylphenol and oxygenated by-products thereof, said process comprising distilling said mixture in a first distillation step operated under reduced pressure to separate a distillate comprising essentially diethylbenzene from a first residue comprising ethylphenol and the oxygenated by-products of said mixture, withdrawing said residue and distilling said first residue in a second distillation step operated under reduced pressure to separate a distillate consisting essentially of ethylphenol from a second residue containing from 30 to 40 mole % of ethylphenol in admixture with said oxygenated by-products, withdrawing said second residue and mixing it with the distillate from the first distillation step, treating the resulting mixture with an aqueous alkaline solution to form

Abstract: A low boiling, water immiscible medium is directly contacted in liquid state with relatively hot or warm water (e.g. with hot recycled fresh water in a desalination system or with warm surface sea water in an energy production system) and in vapor state with relatively cold or cool water (e.g. surface sea water in a desalination system or deep sea water in an energy production system) whereby thermal energy is efficiently transferred between the phases that are so contacted; the energy transfer is for the purpose of evaporating the immiscible liquid in an energy production system and is for the purpose of evaporating saline water in a desalination system; and the effluent from the process which is returned to its natural environment (e.g. to the sea) is treated to remove all significant amounts of entrained and dissolved immiscible medium.

Abstract: A process for regenerating working solutions used in cyclic processes for the manufacture of hydrogen peroxide using anthraquinones, the process consisting of a first distillation stage in which the solvent is separated under a pressure not greater than atmospheric pressure, and a second distillation stage in which the quinones and "light degraded products" are separated under a lower pressure. All the distillation products are used as a new working solution, the vapors of the second distillation stage being condensed on a liquid film of constantly renewed cold solvent originating from condensable vapors of the first distillation stage.