Abstract: A complex mixture of polyols cannot be easily separated by atmospheric or reduced pressure distillation because of the closeness of their boiling points. A mixture of polyols can be readily separated by azeotropic distillation. Typical effective agents are: p-xylene for propylene glycol from 2,3-butanediol and 1,2-butanediol; diisobutyl ketone for ethylene glycol from 1,2-butanediol and 1,3-butanediol; dipentene for glycerine from triethylene glycol and 1,2,4-butanetriol; propylene glycol isobutyl ether for 2,3-butanediol from propylene glycol.

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: Vinyl acetate cannot be easily removed from ethyl acetate by distillation because of the closeness of their boiling points. Vinyl acetate can be readily separated from ethyl acetate by means of extractive distillation. Typical effective agents are formic acid, formamide and formic acid-formamide mixture.

Abstract: Formic acid cannot be easily removed from acetic acid by distillation because of the closeness of their vapor pressures. Formic acid can be readily removed from acetic acid by extractive distillation. Typical extractive distillation agents are acetyl salicylic acid and butyl benzoate; acetyl salicylic acid and ethylene carbonate.

Abstract: Diastereomers can be separated with good industrial success with the aid of extractive distillation. The separation process is characterized in that an auxiliary which changes the partial pressure of the various diastereomers to be separated to a different degree and thus allows easier separation of the diastereomers by distillation is added during the distillation. Using the present process diastereomic cis/trans-permetric acid methyl esters and mixtures of menthol and isomenthol can be separated with isolation of 99% pure product.

Abstract: Meta and para-diisopropylbenzenes cannot be easily separated from each other by distillation because of the closeness of their vapor pressures. m-Diisopropylbenzene can be readily removed from p-diisopropylbenzene by azeotropic distillation using certain nitrogenous compounds. Typical effective azeotropic distillation agents are ethanolamine and benzonitrile.

Abstract: Isopropyl acetate cannot be completely removed from isopropyl acetate--isopropanol--water mixtures by distillation because of the presence of the minimum ternary azeotrope. Isopropyl acetate can be readily removed from mixtures containing it, isopropanol and water by using extractive distillation in which the extractive agent is a mixture of a polyol and one or higher boiling oxygenated, nitrogenous and/or sulfur containing organic compounds. Typical examples of effective agents are 1,3-butanediol and dimethylsulfoxide; 1,2,6-hexanetriol, dimethylsulfoxide and dimethylformamide.

Abstract: m-Xylene is difficult to separate from o-xylene by conventional distillation or rectification because of the close proximity of their boiling points. m-Xylene can be readily separated from o-xylene by using extractive distillation in which the extractive agent is dimethylsulfoxide or a mixture of it with certain high boiling organic compounds. Typical examples of effective agents are: dimethylsulfoxide; dimethylsulfoxide and 1,4-butanediol; dimethylsulfoxide, nitrobenzene and diethylene glycol.

Abstract: Formic acid cannot be completely removed from formic acid and water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from formic acid - water mixtures by extractive distillation in which the extractive agent is ethylene carbonate or propylene carbonate, either alone or mixed with certain high boiling organic compounds. Examples of effective agents are ethylene carbonate and heptanoic acid; propylene carbonate, benzoic acid and isophorone; propylene carbonate, heptanoic acid and 2-hydroxyacetophenone.

Abstract: A process is disclosed for the separation of aromates from hydrocarbon mixtures of optional aromate content through extractive distillation using N-substituted morpholine displaying substituents having no more than 7 C-atoms as selective solvent. Part of the solvent is delivered to the uppermost plate of the extractive distillation column and the remainder of the solvent, preferably amounting to between 10 and 40% by weight, is introduced into the extractive distillation column in at least two partial streams onto plates above the inlet for the hydrocarbon mixture. The temperature of the respective solvent partial streams is adjusted to neither exceed the temperature of the corresponding delivery plates nor fall below this temperature by more than 10.degree. C.

Abstract: Method and improved apparatus for recovering a volatile organic material, such as caprolactam, from a liquid mixture of organic and inorganic materials are disclosed. The method features the step of mixing the liquid mixture with superheated steam for 0.005 to 1.0 second to vaporize a large portion of the volatile organic material without degrading the organic materials. The steam and vaporized organic materials are then separated from the liquid mixture remaining, followed by separation of the vaporized organic material from the steam. The vaporized organic material subsequently is condensed. The improved apparatus features means for introducing superheated steam into a vaporizer feed pipe, as well as means for mixing the superheated steam with the liquid mixture in the pipe for 0.005 to 1.0 second so that a large portion of the volatile organic material is vaporized and feeds with the steam and remaining liquid mixture into the vaporizer for separation.

Abstract: Impure formic acid cannot be completely removed from formic acid-water-impurity mixtures by distillation because of the presence of the maximum azeotrope between formic acid and water. Formic acid can be readily removed from mixtures containing it, water and impurities of the ether, ester, ketone or diketone type by using extractive distillation in which the extractive agent is a higher boiling oxygenated, nitrogenous or sulfur containing organic compound or a mixture of these. Examples of effective agents are adiponitrile; sulfolane and salicyclic acid; dimethylformamide, N,N-dimethylacetamide and ethylene glycol ethyl ether acetate.

Abstract: Acetic acid cannot be easily removed from acetic acid--water mixtures by distillation because of the closeness of their boiling points and the deviation from ideal solution behavior. Acetic acid can be readily removed from mixtures containing it and water by using extractive distillation in which the extractive distillation agent is a mono carboxylic acid, either singly or admixed with high boiling organic compounds. Typical examples of effective agents are pelargonic acid; heptanoic acid and isophorone; neodecanoic acid, acetophenone and nitrobenzene.

Abstract: Isobutyl acetate cannot be completely removed from isobutyl acetate - isobutanol - water mixtures by distillation because of the presence of the minimum ternary axeotrope. Isobutyl acetate can be readily removed from mixtures containing it, isobutanol and water by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated, nitrogenous and/or sulfur containing organic compound or a mixture of these. Typical examples of effective agents are dimethylsulfoxide; dimethylsulfoxide and dimethylformamide; dimethylsulfoxide, dimethylformamide and N,N-dimethylacetamide.

Abstract: Isopropanol cannot be completely removed from isopropanol--isopropyl acetate--water mixtures by distillation because of the presence of the minimum ternary azeotrope. Isopropanol can be readily removed from mixtures containing it, isopropyl acetate and water by using extractive distillation in which the extractive agent is a higher boiling benzoate mixed with certain oxygenated or nitrogeneous organic compounds. Typical examples are butyl benzoate and ethylene carbonate; methyl benzoate, 2-nitropropane and n-decanol.

Abstract: Isopropanol cannot be completely removed from isopropanol-isopropyl acetate-water mixtures by distillation because of the presence of the minimum ternary azeotrope. Isopropanol can be readily removed from mixtures containing it, isopropyl acetate and water by using extractive distillation in which the extractive agent is a higher boiling ester of phthalic acid. Typical examples of effective agents are diisooctyl phthalate and methyl benzoate, dibutyl phthalate, methyl benzoate and nitromethane.

Abstract: Isopropyl acetate cannot be completely removed from isopropyl acetate - isopropanol - water mixtures by distillation because of the presence of the minimum ternary azeotrope. Isopropyl acetate can be readily removed for mixtures containing it, isopropanol and water by using extractive distillation in which the extractive agent is higher boiling oxygenated or nitrogenous organic compound or a mixture of these. Typical examples of effective agents are dimethylformamide; dimethylformamide and triethanolamine; N,N-dimethylacetamide and N-methyl pyrrolidone.

Abstract: Isopropyl acetate cannot be completely removed from isopropyl acetate - isopropanol - water mixtures by distillation because of the presence of the minimum ternary azeotrope. Isopropyl acetate can be readily removed from mixtures containing it, isopropanol and water by using extractive distillation in which the extractive agent is a higher boiling oxygenated or nitrogenous organic compound or a mixture of these. Typical examples of effective agents are diethanolamine; ethanolamine and N-methyl pyrrolidone; triethanolamine and N-methyl pyrrolidone.

Abstract: n-Propyl acetate cannot be completely removed from n-propyl acetate - n-propanol - water mixtures by distillation because of the presence of the minimum ternary azeotrope. n-Propyl acetate can be readily removed from mixtures containing it, n-propanol and water by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated or nitrogenous organic compound or a mixture of these. Typical examples of effective agents are N-methylpyrrolidone; triethanolamine; N-methylpyrrolidone and ethylene glycol.

Abstract: Isopropanol cannot be completely removed from isopropanol-isopropyl acetate-water mixtures by distillation because of the presence of the minimum ternary azeotrope. Isopropanol can be readily removed from mixtures containing it, isopropyl acetate and water by using extractive distillation in which the extractive agent is a higher boiling ester of phthalic acid. Typical examples of effective agents are diethyl phthalate, diisooctyl phthalate and methyl benzoate, dibutyl phthalate, methyl benzoate and nitromethane.

Abstract: Isopropanol cannot be completely removed from isopropanol - isopropyl acetate - water mixtures by distillation because of the presence of the minimum ternary azeoptrope. Isopropanol can be readily removed from mixtures containing it, isopropyl acetate and water by using extractive distillation in which the extractive agent is a higher boiling benzoate or nitro paraffin. Typical examples are methyl benzoate; methyl benzoate and nitromethane; butyl benzoate, nitromethane and nitroethane.

Abstract: Methyl t-butyl ether cannot be separated from close boiling hydrocarbons by distillation because of the proximity of their boiling points. Methyl t-butyl ether can be readily separated from close boiling hydrocarbons by using extractive distillation in which the extractive agent is higher boiling oxygenated, nitrogenous and/or sulfur containing organic compound or a mixture of two or more of these. Typical examples of effective agents are dimethylsulfoxide; dimethylsulfoxide and 2-octanone; dimethylsulfoxide, dimethylformamide and N-methyl pyrrolidone.

Abstract: Water cannot be completely removed from ethanol by distillation because of the presence of the minimum azeotrope. Ethanol can be readily dehydrated by using extractive distillation in which the water is removed as overhead product and the ethanol and extractive agent as bottoms and subsequently separated by conventional rectification. Typical examples of suitable extractive agents are hexahydrophthalic anhydride; methyl tetrahydrophthalic anhydride and pentanol-1; trimellitic anhydride, ethyl salicylate and resorcinol.

Abstract: Formic acid cannot be completely removed from formic acid - water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from mixtures containing it and water by using extractive distillation in which the extractive distillation agent is a sulfone. Typical examples of effective agents are thiophan sulfone; dimethyl sulfone and adiponitrile; phenyl sulfone, adiponitrile and acetophenone.

Abstract: A process for recovering 3-methyl-1-butene from a hydrocarbon stream by treating the stream with a dimethylformamide/sulfolane solvent mixture to remove compounds which form azeotropes with 3-methyl-1-butene and separating the remaining stream.

Abstract: N-propanol and allyl alcohol cannot be separated from each other by distillation because of the proximity of their boiling points. N-propanol can be readily separated from allyl alcohol by using extractive distillation in which the extractive agent is a higher boiling oxygenated, nitrogenous and/or sulfur containing organic compound or a mixture of two or more of these compound. Examples of effective agents are: dimethylsulfoxide; acetamide and ethylene glycol phenylether; adiponitrile; N,N-dimethylacetamide; dimethylformamide; and sulfolane.

Abstract: Methyl acetate cannot be completely removed from methyl acetate - methanol mixtures by distillation because of the presence of the minimum binary azeotrope. Methyl acetate can be readily removed from mixtures containing it and methanol by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated, nitrogenous and/or sulfur containing organic compound or a mixture of these. Typical examples of effective agents are dimethylformamide; dimethylsulfoxide plus tetraethylene glycol, dimethylsulfoxide plus 1,5-pentanediol plus 1,6-hexanediol.

Abstract: An extractive distillation process for selectively separating an ethylenically unsaturated hydrocarbon from a mixture containing hydrocarbon liquids having similar boiling points wherein an amine acts as a selective solvent and polymerization inhibitor. For example, styrene can be separated from a mixture of styrene and o-xylene using aminoethyl piperazine as the solvent for the distillation.

Abstract: A method for separating carboxylic acids from mixtures with non-acids by an extractive distillation method using a lactam with a 5- or 6-membered ring, preferably N-methyl-2-pyrrolidone, as an extractant to extract the acids from the mixture with non-acids, followed by separating the extracted acids from the extractant by rectification.

Abstract: 2,4-Dihydroxybenzophenone is prepared substantially quantitatively and in a highly purified form by reacting resorcinol with a benzotrihalide in the presence of an aqueous solution of N-methylpyrrolidone and subsequently subjecting the crude reaction product mixture to vacuum distillation.

Abstract: Isopropyl ether cannot be completely removed from isopropyl ether-isopropanol-water mixtures by distillation because of the presence of the minimum ternary azeotrope. Isopropyl ether can be readily removed from mixtures containing it, isopropanol and water by using extractive distillation in which the extractive distillation agent is dimethylsulfoxide with or without a mixture of higher boiling oxygenated and/or nitrogenous organic compounds. Typical examples are dimethylsulfoxide; dimethylsulfoxide and ethylene glycol; dimethylsulfoxide, dimethylformamide and 1,4-butanediol.

Abstract: A process for producing anhydrous ethanol from an ethanol-water mixture feedstock comprising subjecting the feedstock to distillation in a first distillation zone to produce an overhead vapor of from about 80 to about 90 weight percent ethanol, subjecting the thus produced overhead vapor to extractive distillation in an extractive distillation zone to produce anhydrous ethanol vapor overhead of about 99.5 weight percent ethanol and a solvent-rich bottom stream, and stripping the solvent-rich bottom stream and recycling the thus produced lean solvent bottom stream to the extractive distillation zone and recycling the thus produced overhead vapor stream to the first distillation zone. Also disclosed is a system for performing the process.

Abstract: Methanol cannot be completely removed from methanol-methyl acetate mixtures by distillation because of the presence of the minimum binary azeotrope. Methanol can be readily removed from mixtures containing it and methyl acetate by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated or nitrogenous organic compound or a mixture of these. Typical examples of effective agents are: ethylene glycol phenyl ether, ethylene carbonate, nitromethane, 2-nitrotoluene, 1-nitropropane plus propylene carbonate.

Abstract: Isopropyl ether cannot be completely removed from isopropyl ether - methyl ethyl ketone mixtures by distillation because of the presence of the minimum binary azeotrope. Isopropyl ether can be readily removed from mixtures containing it and methyl ethyl ketone by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated and/or nitrogenous organic compound or a mixture of these. Typical examples of effective agents are adiponitrile; ehtylene carbonate plus dimethylformamide; adiponitrile plus dimethylformamide plus glycerine.

Abstract: n-Butyl acetate cannot be completely removed from n-butyl acetate - n-butanol - water mixtures by distillation because of the presence of the minimum ternary azeotrope. n-Butyl acetate can be readily removed from mixtures containing it, n-butanol and water by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated, nitrogenous and/or sulfur containing organic compound or a mixture of these. Typical examples of effective agents are dimethylsulfoxide; dimethylsulfoxide and 1,4-butanediol; dimethylsulfoxide, dimethylformamide and 1,6-hexanediol.

Abstract: Benzene is virtually impossible to separate from similar close boiling non-aromatic hydrocarbons by conventional rectification or distillation. Benzene can be readily separated from similar boiling non-aromatic hydrocarbons by using extractive distillation in which the extractive agent is a mixture of benzoic acid, maleic anhydride and/or phthalic anhydride plus a suitable solvent. A typical mixture comprises phthalic anhydride, maleic anhydride and adiponitrile.

Abstract: Isopropenylstyrene, present in t-butylstyrene in small quantities as an impurity, is removed by extractive distillation using sulfolane as solvent.

Abstract: Isopropyl ether cannot be completely removed from isopropyl ether-isopropanol-water mixtures by distillation because of the presence of the minimum ternary azeotrope. Isopropyl ether can be readily removed from mixtures containing it, isopropanol and water by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated, nitrogenous and/or sulfur containing organic compound or a mixture of these. Typical examples of effective agents are ethylene glycol; dimethylsulfoxide plus propylene glycol; dimethylsulfoxide plus dimethylformamide plus diethylene glycol diethyl ether.

Abstract: n-Butyl acetate cannot be completely removed from n-butyl acetate-n-butanol--water mixtures by distillation because of the presence of the minimum ternary azeotrope. n-Butyl acetate can be readily removed from mixtures containing it, n-butanol and water by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated, nitrogenous and/or sulfur containing organic compound or a mixture of these. Typical examples of effective agents are N,N-dimethylacetamide, dimethylsulfoxide and acetamide, ethylene glycol propylene glycol, dimethylsulfoxide and acetamide.

Abstract: A process and apparatus are provided controlling the heat input of an extractive distillation column. The bottom of the column is heated with a major stream of thermal energy which is either slowly varying in time or controlled by the amount of starting material mixture and with a minor stream of thermal energy which is controlled by sensing the thermodynamic state in the upper half of the column during the process. The major stream can provide about 90 percent and the minor stream about 10 percent of the heat fed to the column. The minor stream can be controlled by the temperature at one point in the upper half of the column, by the temperature difference at two points in the upper half of the column or by gas chromatographic analysis of the extract material concentration near the top of the column. The process allows one to keep a low concentration of the extract material in the raffinate.

Abstract: m-Xylene is difficult to separate from o-xylene by conventional rectification or distillation because of the close proximity of their boiling points. m-Xylene can be readily separated from o-xylene by using extractive distillation in which the extractive agent is ethyl-2-hydroxybenzoate; propoxypropanol puls 1,4-butanediol; sulfolane plus dimethylsulfoxide plus ethyl benzoate.

Abstract: A method for separating ethyl acetate from methyl ethyl ketone is described including distilling in an anhydrous condition a mixture of ethyl acetate-methyl ethyl ketone in a plate column in the presence of an effective amount of an organic extractive solvent which has the following properties: (1) is soluble in a boiling ethyl acetate-methyl ethyl ketone mixture; (2) does not form an azeotrope with ethyl acetate or methyl ethyl ketone; (3) boils higher than ethyl acetate and methyl ethyl ketone and (4) in combination with the ethyl acetate-methyl ethyl ketone mixture, results in a relative volatility of ethyl acetate to methyl ethyl ketone greater than 1.20.

Abstract: Isopropyl ether cannot be completely removed from isopropyl ether-acetone mixtures by distillation because of the presence of the minimum binary azeotrope. Isopropyl ether can be readily removed from mixtures containing it and acetone by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated or nitrogenous organic compound or a mixture of these. Typical examples of effective agents are: dimethylsulfoxide; sulfolane and propylene glycol; glycerine, ethylene glycol and adiponitrile.

Abstract: Isopropyl ether cannot be completely removed from isopropyl ether - methyl ethyl ketone mixtures by distillation because of the presence of the minimum binary azeotrope. Isopropyl ether can be readily removed from mixtures containing it and methyl ethyl ketone by using extractive distillation in which the extractive distillation agent is a higher boiling oxygenated, nitrogenous and/or sulfur containing organic compound or a mixture of these. Typical examples of effective agents are sulfolane; ethylene carbonate plus dimethylsulfoxide; adiponitrile plus dimethylformamide plus glycerine.

Abstract: A process of extractive distillation for separating components easily soluble in a polar solvent from at least two hydrocarbon mixtures having different contents of the easily soluble components by extractive distillation using said polar solvent, which comprises feeding a hydrocarbon mixture containing a larger amount of the easily soluble components, as a gas, into the middle or lower portion of an extractive distillation column, feeding a hydrocarbon mixture containing a smaller amount of the easily soluble components, as a liquid, to the upper portion of the extractive distillation column, and subjecting them to extractive distillation.

Abstract: A method for separating close-boiling chlorosilanes by the procedures of extractive distillation using sulfolane as the extractive solvent is described. An example of close-boiling chlorosilanes which can be separated by this method include dimethyldichlorosilane and methyltrichlorosilane containing mixtures. The invention comprises heating a mixture of the close-boiling chlorosilanes with sulfolane to distill the lower-boiling chlorosilane from the mixture and thereafter separating the sulfolane and the high-boiling chlorosilane.

Abstract: Production of 2-chloropyridines of the formula I ##STR1## wherein R independently of one another is C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -halogenalkyl, halogen or carboxyl andn is zero or a number from one to four, with the proviso that at most two substituents R can be alkyl, halogenoalkyl or carboxyl at the same time, and that if R is chlorine and n is two, one of them must not occupy the 3- or 5-position of the pyridine ring, by reacting a 2-pyridone of the formula (II) ##STR2## wherein R and n have the meanings given above at 30.degree.-150.degree. C. with phosgene in the presence of an N,N-disubstituted formamide of the formula III ##STR3## in which R.sub.1 and R.sub.2 can be identical or different and are each an alkyl group having 1 to 4 carbon atoms, or R.sub.1 and R.sub.2 together with the nitrogen atom form the pyrrolidino, piperidino or morpholino ring, and in the presence of an inert solvent.2-chloropyridines are valuable intermediates for producing herbicidally active .alpha.

Abstract: An improved method for the separation of close-boiling chlorosilanes is described. The method consists of the extractive distillation of the close-boiling chlorosilanes using sulfolane as the extractive solvent and thereafter separating the higher-boiling chlorosilane and sulfolane by distilling the higher-boiling chlorosilane from the higher-boiling chlorosilane and sulfolane mixture to which is added a hydrocarbon solvent. Preferred hydrocarbon solvents include normal-heptane, normal-nonane, and 2,2,4-trimethylpentane. The sulfolane obtained from the higher-boiling chlorosilane and sulfolane mixture is suitable for recycling to the extractive distillation process as the sulfolane contains only limited amounts of dissolved chlorosilane.

Abstract: A level-controlled water tank in an extractive distillation system is used to maintain the water concentration in the solvent mixture constant.

Abstract: Vinyltoluene is separated from close-boiling, olefinically unsaturated alkylaromatic compounds by extractive distillation. For example, vinyltoluene is separated from cis-.beta.-methylstyrene, and from .alpha.-methylstyrene by extractive distillation using .gamma.-butyrolactone as the extracting agent.